Peptidic blocks for nucleic acid delivery

Abstract

A polypeptide conjugate for use in a method for binding and/or internalization of the polypeptide conjugate to a mammalian cell having a transferrin receptor (TFRC) and/or receptor for advanced glycation end products (RAGE). The polypeptide conjugate may be used in a method for targeting of a drug delivery system or diagnostic delivery system.

Claims

1. A therapeutic composition, comprising: a peptide segment which is SEQ ID NO. 2 and pharmaceutically acceptable salts or esters thereof; and a cysteine residue at the N-terminus or C-terminus of the peptide segment.

2. The therapeutic composition of claim 1, wherein the cysteine residue is at the C-terminus of the peptide segment.

3. The therapeutic composition of claim 1, wherein the cysteine residue is at the N-terminus of the peptide segment.

4. The therapeutic composition of claim 1, further comprising a nucleic acid.

5. The therapeutic composition of claim 2, further comprising a nucleic acid.

6. The therapeutic composition of claim 3, further comprising a nucleic acid.

7. The therapeutic composition of claim 4, wherein the nucleic acid is in the form of one of: mRNA, circular RNA, catalytic RNA, RNA decoys, linear DNA, plasmid DNA, a sequence of nucleic acid encoding a desired gene, nucleic acid attached to an enzyme, therapeutic nucleic acid and an expression conjugate that comprises a nucleic acid that encodes a therapeutic protein, an enzyme attached to a clustered regularly interspaced short palindromic repeats, shRNA, miRNA, siRNA, circular siRNA, an anti-sense molecule, locked nucleic acids, aptamer, peptide nucleic acids, splice modulating oligonucleotide, LNA/DNA, and LNA/RNA mix-mer oligonucleotides.

8. The therapeutic composition of claim 7, wherein the nucleic acid is deoxyribonucleic acid.

9. The therapeutic composition of claim 5, wherein the nucleic acid is deoxyribonucleic acid.

10. The therapeutic composition of claim 6, wherein the nucleic acid is deoxyribonucleic acid.

11. The therapeutic composition of claim 5, wherein the nucleic acid is ribonucleic acid.

12. The therapeutic composition of claim 6, wherein the nucleic acid is ribonucleic acid.

13. The therapeutic composition of claim 7, wherein the nucleic acid is ribonucleic acid.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic illustration of the polypeptide conjugate.

(2) FIG. 2 is schematic illustration of a self-aggregation model of FAM-CGY nanoparticles using ChemBioOffice software where the polypeptide is linked to FAM. It is further illustrated how the peptide conjugate self-assemble into a nanoparticle or a fiber form through the formation of disulphide bridges, hydrogen bonding, possible salt-bridges and hydrophobic interaction including π-π interactions.

(3) FIG. 3A represents nanoparticle size analysis by Nanosight Particle Tracking (NTA) of different concentrations of FAM-CGY peptide in MQ water. Corresponding representative NTA video frame is also shown (B). This is in accord with the critical aggregation concentration of FAM-CGY, which is 2.5 micromolar and shown in FIG. 6A. FIG. 3B shows representative NTA video frames of nanoparticle scattering from particle size analysis in FIG. 3A. The arabic numeral on the down-left corner of the video frame represent the count number of scattered particles within the analysed frame.

(4) FIG. 4 is a graph showing the relation between the peptide concentration, particle concentration and size. The CGY-peptide is with and without FAM at the N-terminal.

(5) FIG. 5 is a graph showing the effect of pH on size and concentration of the FAM-CGY-peptide-aggregates. A 5 μM FAM-CGY peptide working solutions was prepared in 10 mM HEPES buffer, pH values were adjusted with 1M HCL or 1M NaOH.

(6) FIG. 6. Characterization of FAM-CGY peptidic nanoparticles FIG. 6A. critical aggregation concentration measurement, FIG. 6B. atomic force microscopy (AFM) representation of aggregated FAM-CGY peptides showing a network of globular and fibre structures, FIG. 6C. graph of particle size distribution measured by NTA, and FIG. 6D. far-UV CD spectra of FAM-CGY peptide at various pH.

(7) Live-cell fluorescence microscopy of hCMEC/DE3 cells uptake of different variations of FAM-labeled CGY-peptides. FIG. 7A. 10 μM 5′-FAM (negative control), FIG. 7B. 5 μM 5′ labeled CGY-peptide (FAM-CGY), FIG. 7C. 5 μM 3′ labeled CGY-peptide (CGY-FAM), FIG. 7D. 5 μM FAM-d-CGY, FIG. 7E. 5 μM FAM-CGY scrambled 1, FIG. 7F. 5 μM FAM-CGY scrambled 2. The hCMEC/DE3 cells were incubated with different variations of FAM-labeled CGY-peptides for 24 h, and washed 3 times with PBS. The nucleus was stained with Hoechst 33342 (5 μg/mL), insert bars=50 μm.

(8) FIG. 8 Single- and live-cell fluorescence microscopy showing hCMEC/DE3 cells uptake of different variations of FAM-labeled CGY-peptides. The cells were stained with CellLight® Actin-RFP and Hoechst 33342. Insert bars=20 μm.

(9) FIG. 9 Quantification of FAM labeled CGY-peptide uptake in different cell lines by fluorescence-activated cell sorting (FACS). The cells were incubated with 5 μM of different variations of FAM-labeled CGY-peptides at 37° C. for 24 h.

(10) Dose and time-depended vesicular uptake of FAM-CGY peptide in hCMC/DE3 cells. Cells were treated with various concentrations of FAM-CGY peptide ranging from 0-20 μM and stained with Hoechst 33342. FIG. 10A. Fluorescence microscopy after 24 h. FIG. 10B. hCMC/D3 cells were subjected to 5 μM FAM-CGY nanoparticles and studied with fluorescence microscopy at different time-intervals from 0-48 hours. and FIG. 10C. Quantification of peptide uptake from (a) by FACS, and FIG. 10D. quantification of uptake from (c) by FACS. The cells were stained with CellLight® Actin-RFP and Hoechst 33342, Insert bars=20 μm.

(11) Influence of various endocytic inhibitors on the hCMEC/D3 cells uptake of FAM-CGY peptidic nanoparticles. FIG. 11A. FACS analysis of hCMEC/D3 cells incubated with FAM-CGY peptidic nanoparticles or transferrin in the presence different inhibitors. The graph displays mean fluorescence intensities of one of three independent experiments performed in duplicate. The FAM-d-CGY and transferrin were also chosen as controls to perform the inhibition experiments. FIG. 11B. Shows the influence of morphology on the hCMEC/D3 cell uptake of FAM-CGY peptidic nanoparticles in presence of various inhibitors by fluorescence microscopy. Energy dependent inhibitor: 1 mM 2-deoxy-D-glucose (DOG) and 1 mM NaN3. Macropinocytosis inhibitor: 10 μM worthmanin (WOR). Fluid phase endocytosis inhibitor: 20 μM nocodazole (NOC). Clathrin-dependent inhibitor: 30 μM chlorpromazine (CPZ). Caveolae-medicated inhibitor: 5 μM N-ethylmaleimide (NEM). Caveolae-dependent endocytosis: 200 μM indomethacin (IMC). Cell nucleus were stained with Hoechest 33342, insert bars=25 μm.

(12) FIGS. 12A, 12B, and 12C are graphs illustrating a complement activation experiment. The complement activation products FIG. 12A. SC5d-9, FIG. 12B. C5a, and FIG. 12C. C3a were quantified in healthy human serum after incubation of CGY, FAM-CGY and FAM-d-CGY peptide at low and high concentration. Background noise and positive control (Zymosan) are presented for each product. Complement activation and fixation is a fundamental process contributing to macrophage clearance of intravenously injected nanoparticles. Accordingly, complement activation studies in human serum were performed with low and high concentrations of FAM-CGY peptide and other peptides (CGY, FAM-d-CGY) for comparison. The FAM-CGY nanoparticles had no significant effect on the level of complement activation products SC5d-9, C5a, and C3a. The responses were relatively low, and close to the background activation. Only a slight level of complement activation was observed compared to the positive control (Zymosan). There were no systematic differences between the activation below and above CMC. Conclusion: The FAM-CGY nanoparticles are unlikely to induce complement-mediated immune reactions following intravenous injection.

(13) FIG. 13 is a Western blot and chart showing the quantification of the TFRC expression in different cell lines: human brain endothelial cell line (hCMEC/D3), human mammary Epithelial Cell Line (MCF-10A), human breast cancer cell line (MCF-7), human epithelial carcinoma cell line (HeLa), human umbilical vein endothelial cells (HUVEC) and human lung carcinoma cells (H1229).

(14) FIG. 14 is chart showing the uptake of FAM-CGY quantified by FACS. MCF-7 and MCF-10A cells were incubated with different concentration of FAM-CGY as indicated for 24 h and studied by fluorescence microscopy (not shown).

(15) FIG. 15 is a chart showing the level of competition for TFRC binding of FAM-CGY nanoparticles and different concentrations of transferrin (62.5, 250 nM or 500 nM) analyzed by fluorescence microscopy (not shown) and quantified by FACS.

(16) FIGS. 16A and 16B show blockage of FAM-CGY nanoparticle uptake after knocking down the TFRC expression. FIG. 16A shows a downregulated TFRC expression after using a commercial transfection reagent siPORT Amine/TFRC siRNA complex for 72 h in hCMEC/D3 cells and a unspecific siRNA (siControl) as a positive control. FIG. 16B shows blockage of FAM-CGY nanoparticle uptake in TFRC knocked down hCMEC/D3 cells. The cells with low TFRC expression and siControl transfection cells were incubated with 5 μM FAM-CGY nanoparticles and 62.5 nM transferrin (positive control) for 16 h, respectively, the FAM-CGY nanoparticles and transferrin uptake were detected by fluorescence microscopy (not shown) and b. quantified by FACS. Cell nucleus stained with Hoechest 33342, Insert bars=50 μm.

(17) FIGS. 17A through 17G show FAM-CGY nanoparticles competed with different concentrations of RAGE receptor substrate or amyloid-β peptide. FIGS. 17A through 17G were analyzed by fluorescence microscopy. FIG. 17H is quantified by FACS.

(18) FIG. 18A shows downregulated RAGE expression using a commercial transfection reagent siPORT Amine/RAGE siRNA complex for 72 h in hCMEC/D3 cells and the unspecific siRNA (siControl) as control. FIG. 18B shows blockage of the FAM-CGY nanoparticle uptake in RAGE knocked down hCMEC/D3 cells. The RAGE low expression cells and siControl transfection cells were incubated with 5 μM FAM-CGY nanoparticles and 250 nM amyloid-β peptide (positive control) for 16 h respectively, the FAM-CGY nanoparticles and amyloid-β peptide uptake was detected by fluorescence microscopy (not shown).

(19) FIGS. 19A through 19C show FAM-CGY nanoparticles co-competed with transferrin, RAGE peptide or amyloid-β peptide. FIG. 19A was analyzed by fluorescence microscopy and FIGS. 19B and 19C were quantified by FACS.

(20) FIG. 20 Real-time trafficking FAM-CGY nanoparticles endocytosis. hCMEC/D3 cells were stained with wheat germ agglutinin (WGA)-Texas Red®-X and Hoechest 33342. Insert white frames are image amplifications. The arrows indicate the peptidic nanoparticles binding to the membrane of the cell surface or having just crossed the cell membrane. Insert bars=10 μm.

(21) FIG. 21 Schematic illustration of the internalization mechanism of the FAM-CGY nanoparticles in hCMEC/D3 cell based on fluorescence microscopy experiments using CellLight® Early endosomes-RFP, Lysosomes-RFP, Golgi-RFP, and Endoplasmic reticulum (ER)-RFP to stain the cell organelles (not shown). Peptidic nanoparticle binds 1 to the cell surface with high affinity. After being internalized by transferrin receptor-mediated endocytosis 2 in early endosomes, the peptidic nanoparticles were transported from the early endosomes to the lysosomes and then released 4 into the cytosol. Experiments were unclear if peptidic nanoparticles were transported within the ER and Golgi apparatus.

(22) FIGS. 22A and 22B are characterizations of siRNA/FAM-CGY complexes. FIG. 22A NTA of siRNA/FAM-CGY complexes. FIG. 22B. Size distribution of siRNA/FAM-CGY complexes measured of NTA.

(23) FIG. 23 Transmission electron microscopy image of FAM-CGY/Cy3-siRNA fiber complexes with an average length of 297±87 nm and width of 50±11 nm.

(24) FIG. 24 Transmission electron microscopy image FAM-CGY/ciRNA (circular RNA) nanoparticles complexes with an average diameter of 180±29.

(25) Transfection efficiency studies of siRNA/FAM-CGY complexes. FIG. 25A. Suppression of transferrin receptor expression by different amounts of TFRC siRNA with or without complex formation with FAM-CGY. Transferrin receptor expression was measured 72 h after transfection. FIG. 25B. Time dependent downregulation of the transferrin receptor by TFRC siRNA/FAM-CGY complexes.

(26) Cell viability assessment following treatment of cells with the fluorescent peptide FIG. 26A or siRNA/FAM-CGY complex FIG. 26B for 24 h, determined by LDH assay (n=6). Background: untreated cells. To examine the cytotoxicity of the peptide and the siRNA/FAM-CGY complex, the hCMEC/D3 cells were incubated with concentrations 1, 2, 5, 10, 20 μM of the peptide and different relations of siRNA/FAM-CGY complexes (8:5, 16:5 or 24:5) for 24 h, the viability of cells without treatment was used as a control. The cytotoxicity was measured by a LDH assay. The LDH assay measures the membrane integrity as a function of the amount of cytoplasmic LDH leaked into the medium.

(27) Investigation of oxygen consumption rate (OCR) in hCMEC/D3 cells following incubation with FAM-CGY peptide or siRNA/FAM-CGY complex. The hCMEC/D3 cells were incubated with concentrations 2, 5, 10 or 20 μM of the FAM-CGY peptide for FIG. 27A 8 hours, or FIG. 27B 24 hours, or FIG. 27C different formulation of siRNA/FAM-CGY complex for 24 hours. OCR was monitored in real-time using XF Analyzer (Seahorse Bioscience) and data was thereafter corrected for cell numbers. Untreated cells and cells incubated with different dilutions (100-fold or 300-fold) of Amine or siRNA/Amine group were used as controls. FIG. 27D Standard curve showing the linear relationship between absorbance values from crystal violet staining and hCMEC/D3 cell numbers.

(28) Blockage of amyloid-β peptide uptake by FAM-CGY nanoparticles analyzed by fluorescence microscopy (not shown) and quantified by FACS. FIG. 28A shows a diagram of the number of green cell counts of cells having FAM-CGY bound. FIG. 28B shows a diagram of the number of red cell counts of cells having amyloid-β bound.

(29) FIG. 29A represents schematic illustration of an in vitro set up for photo-activation of FAM-CGY. The light with designated wavelength is shone from the above using a halogen light source. The dish contain cells with internalised FAM-CGY nanoparticles. These particles are internalised within endo-lysosomal compartments. On photo activation, FAM-CGY destabilises endosomes and FAM-CGY conjugates are released into the cytoplasm. FIG. 29B represents a schematic illustration of an in vitro method light-triggered release of FAM-CGY nanoparticles from compartment vesicles to the cytoplasm using a specific wavelength of light. b. Fluorescence microscopy image of hCMEC/D3 cells exposed to 488 nm light at time points 0, 2, 2.30, 4 or 6 minutes. The cells were incubated with FAM-CGY nanoparticles for 24 h at 37° C.

(30) FIG. 30 Light-triggered release of FAM-CGY nanoparticles from compartment vesicles to cytoplasm. hCMEC/D3 cells exposed to the 488 nm light at 0, 4, 8, 10, 11, 13 or 14 minutes. The cells were incubated with FAM-CGY nanoparticles for 24 h at 37° C. prior light exposure.

(31) FIG. 31 Fluorescence microscopy image of energy dependent controlled release of FAM-CGY nanoparticles from compartment vesicles to cytoplasm. hCMEC/D3 cells were exposed to differential interference contrast microscopy (DIC), and wavelengths of 488 (green), 405 (blue) or 635 (red) nm at different times; 0, 4, 5 or 6 min for the green light, 0 or 30 for DIC, 0, 4, 12 or 20 min for blue light and 0 or 30 for red light. Due to lack of light-triggered release after DIC and red light, those cells were following exposed to green light for 4 and 6 minutes to release the FAM-CGY nanoparticles. All cells were incubated with FAM-CGY nanoparticles for 24 h at 37° C. prior light exposure.

(32) FIGS. 32A, 32B, and 32C are fluorescence microscopy images of in vitro light-triggered release of siRNA by FAM-CGY nanoparticles into the cytoplasm. The fluorescence intensity of the FAM-CGY peptide, Cy3-siRNA and Hoechest 33342 (nucleus stain) in the cytoplasm is measured along the white line in the image. The hCMEC/D3 cells were incubated with Cy3-siRNA/FAM-CGY photosensitive nanoparticle complex at 37° C. for 24 h and exposed to the 488 nm light at 0, 4, and 6 minutes.

(33) FIG. 33A Sequence of FAM-CGY and FAM-GYR-GYR peptide sequence of a. FAM-CGY peptide and FIG. 33B FAM-GYR-GYR, and corresponding molecular energy-minimization models using ChemBioOffice software.

(34) FIGS. 34A and 34B are fluorescence microscopy images of the dose-depended vesicular uptake of FAM-CGY and FAM-GYR-GYR peptide in hCMEC/D3 cells. The cells were treated with concentrations of 1, 2, 5 or 10 μM of FAM-CGY and FAM-GYR-GYR and stained with Hoechest 33342 prior fluorescence microscopy after 24 h (a) (Insert bars=25 μm).

(35) FIG. 35 Comparison of the uptake of FAM-CGY and FAM-GYR-GYR peptide by hCMEC/D3 cells. Cells were treated with concentrations of 1, 2, 5 or 10 μM of FAM-CGY and FAM-GYR-GYR and the peptide uptake were quantified by FACS.

(36) FIG. 36 Influence of various endocytosis inhibitors on the hCMEC/D3 cells uptake of FAM-GYR-GYR peptide. FACS analysis of hCMEC/D3 cells incubated with FAM-GYR-GYR peptide in the presence inhibitors: Energy dependent inhibitor: 1 mM 2-deoxy-D-glucose (DOG) and 1 mM NaN3. Macropinocytosis inhibitor: 10 μM worthmanin (WOR). Fluid phase endocytosis inhibitor: 20 μM nocodazole (NOC). Clathrin-dependent inhibitor: 30 μM chlorpromazine (CPZ). Caveolae-medicated inhibitor: 5 μM N-ethylmaleimide (NEM). Caveolae-dependent endocytosis: 200 μM indomethacin (IMC). The graph displays mean fluorescence intensities of one of three independent experiments performed in duplicate.

(37) FIGS. 37A, 37B, 37C, and 37D are fluorescence microscopy images showing intracellular trafficking of FMA-GYR-GYR peptide in different organelles after 4 h incubation. The hCMEC/D3 cell organelles were labelled with CellLight® Early endosomes-RFP, Lysosomes-RFP, Golgi-RFP, and Endoplasmic reticulum (ER)-RFP, respectively, and the nuclei was stained with Hoechest 33342.

(38) FIG. 38 Fluorescence microscopy image of Cy3-siRNA/FAM-GYR-GYR complex transfection of hCMEC/D3 cells. The cells were incubated with Cy3-siRNA/FAM-GYR-GYR complex as indicated at 37° C. for 1 h or 4 h. The cell nucleus were stained with Hoechest 33342.

(39) Bar chart showing binding of F-liposome alone, F-Liposome-CGY, F-Liposome-FAM-CGY, F-Liposome-CGY-FAM or F-Liposome-FAM-CGY-scrabled2 conjugates to hCMEC/D3 cells. The cells were analysed by FACS. The liposomes in FIG. 39A were labeled with RED Fluorescent phospholipid and in FIG. 39B with green Fluorescent phospholipid.

(40) FIG. 40 is a graph showing size distribution of caprylic acid conjugated CGY peptide as measured by nanoparticle tracking analysis (NTA).

(41) FIGS. 41A through 44D are results of studies illustrating formation of peptidic complexes based on rhodamine-linked CGY (Rh-CGY) peptides.

(42) FIG. 41A shows a typical size distribution profile of Rh-CGY peptide (10 μM) self-assembly determined by NTA. FIG. 41B shows the uptake of Rh-CGY peptide self-assembly in hCMEC/D3 cells.

(43) FIG. 42 is a Western blot showing peptidic complexes in a study of Rh-CGY.

(44) FIG. 43A is a histogram representing a typical size distribution profile of complex species of Rh-CGY (10 μM) with FAM-(C)-NAP peptide (10 μM) determined by NTA. FIG. 43B shows the morphology of Rh-CGY/FAM-(C)-NAP peptidic complex observed by electron microscopy. The Rh-CGY/FAM-(C)-NAP peptide co-self assembles into nanoparticles and fibers. FIG. 43C shows the intracellular intensity of cargoes delivered into hCMEC/D3 cells by the Rh-CGY peptidic based nanosystems using FASC analysis. FIG. 43D is a typical dot plot resulting from a fluorescence-assisted cell sorting experiment of Rh-CGY and FAM-(C)-NAP peptide after treating hCMEC/D3 cells with 10 μM FAM-(C)-NAP, 10 μM Rh-CGY/10 μM FAM-(C)-NAP complex and 10 μM Rh-CGY for 24 h. FIG. 43E is a photograph of living cell microscopy images of the cells from the study of FIG. 43D.

(45) FIG. 44A represents typical size distribution profile of Rh-CGY (10 μM)/FAM-GYR (5 μM) peptidic complex determined by NTA. FIG. 44B shows the morphology of Rh-CGY/FAM-GYR peptidic complex observed by electron microscopy. FIG. 44C is a typical dot plot resulting from a fluorescence-assisted cell sorting experiment of Rh-CGY and FAM-GYR peptide after treating hCMEC/D3 cells with 5 μM FAM-GYR, 10 μM Rh-CGY/5 μM FAM-GYR complex and 10 μM Rh-CGY for 24 h. FIG. 44D is a photograph of live cell microscopy images of the cells from the study of FIG. 44C.

(46) FIG. 45 shows photographs of hCMEC/d3 cells in a study investigating double peptide-mediated nucleic acid transfection.

(47) FIG. 46 shows fluorescence imagery of organs from mice involved in in vivo studies of peptide localization.

(48) FIG. 47 are photographs of brain cells of mice that were involved in in vivo studies of peptide conjugate localization.

(49) FIGS. 48A through 48G demonstrate the structures of peptide conjugate aggregates. FIGS. 48A and 48B are atomic force microscopy (AFM) images of FAM-CGY (5 μM) species in the absence and presence of 24 nM siRNA (in this case, targeted against the transferrin receptor), respectively. The inset in FIG. 48B is transmission electron micrograph of elliptically-shaped FAM-CGY/siRNA complexes showing the presence of some elongated fibre-like structures in the particle core. The spherical equivalent mean size of nanoparticles is 169±51 nm, based on measurements of at least 100 individual images. FIGS. 48C, 48D, 48E, 48F, and 48G show an overview of peptide nanoparticle-fiber network (48C), a typical core-shell nanoparticle component of the network (48D), a core-shell nanoparticle with elongated hair-like projections (48E), and magnified views of twisted fibre components (48F, 48G). The measured mean size of the core-shell nanoparticles were 116±22 nm (based on measurements of at least 100 randomly selected nanoparticle images.)

DETAILED DESCRIPTION

(50) This section describes the current invention in greater detail using a schematic illustration of a polypeptide conjugate and examples of polypeptide conjugates and their use in a method to for binding and/or internalization of the polypeptide conjugate to a mammalian cell having a transferrin receptor (TFRC) and/or receptor for advanced glycation end products (RAGE). However, this by no means limits the scope of the current invention.

(51) FIG. 1 shows a schematic drawing of a polypeptide conjugate with a moiety 1 and connected to a linker 2. A second moiety 5 may be linked to the linker 2. The linker is also linked to polypeptide sequence Gly-Tyr-Arg-Pro-Val-His-Asn-Ile-Arg-Gly-His-Trp-Ala-Pro-Gly 3 which may be connected to one or more polypeptides 3 by a spacer 4.

EXAMPLES

Example 1: Self-Assembly of Polypeptide Conjugate

(52) Scrambled peptides and fluorescence-labelled peptides were designed and synthesized as shown in table 1. To investigate whether the polypeptide conjugate can self-assemble, Nanoparticle Tracking Analysis (NTA) technology was employed to detect the peptide aggregation. Briefly, 1 mL peptide solutions with different concentrations (0.5, 1, 2.5 and 5 μM) were prepared by diluting the peptide stock solutions (500 μM) with MQ water and incubate for 30 min at room temperature. NTA measurements were performed with a NanoSight LM20 (NanoSight Ltd., Amesbury, United Kingdom) equipped with a sample chamber with a 405 nm blue laser and a Viton fluoroelastomer O-ring. The peptide samples were injected in the sample chamber with sterile syringes (BD Discardit II, New Jersey, USA) until the liquid reached the tip of the nozzle. All measurements were performed at room temperature. For the pH effect of FAM-CGY peptide assembly, FAM-CGY stock solution (500 μM) was diluted into 5 μM with 10 mM HEPES buffer where pH values were adjusted with 1 M HCl or 1 M NaOH, respectively.

(53) FAM-CGY self-assembles into nanoparticles and fibres as shown in FIG. 2. The size of the self-assembled FAM-CGY nanoparticles are 2-200 nm depending on the peptide conjugate concentration.

(54) TABLE-US-00001 TABLE 1 SEQ ID Molecular Peptide Modified site Peptide sequence NO. weight Purity CGY Unlabel peptide Cys-Gly-Tyr-Arg-Pro- 3 1820.04 98.11% Val-His-Asn-Ile-Arg-Gly- His-Trp-Ala-Pro-Gly FAM-CGY Original peptide 5-FAM-Cys-Gly-Tyr-Arg- 4 2178.36 98.91% Pro-Val-His-Asn-Ile-Arg- Gly-His-T rp-Ala-Pro-Gly CGY-FAM 5-FAM Cys-Gly-Tyr-Arg-Pro- 5 2305.53 98.36% C-terminal Val-His-Asn-Ile-Arg-Gly- peptide, His-Trp-Ala-Pro-Gly-Lys- 5-FAM effect 5-FAM FAM-d-CGY D form amino 5-FAM-dCys-dGly-dTyr- 6 2177.36 98.34% acid affect dArg-dPro-dVal-dHis- dAsn-dIle-dArg-dGly- dHis-dT p-dAla-dPro- dGly FAM-CGY Change the 5-FAM-Cys-Gly-Tyr-Arg- 7 2177.36 98.56% Scrambled 1 position of Arg, Pro-Val-His-Asn-Ile-Gly- the charge effect His-Trp-Arg-Ala-Pro-Gly FAM-CGY Without 5-FAM-Cys-Gly-Tyr-Arg- 8 2048.20 98.26% Scrambled 2 Tryptophan, Pro-Val-His-Asn-Ile-Arg- relative the Gly-His-Gly-Ala-Pro-Gly Tryptophan effect

Example 2: Specific Binding to and Cellular Uptake of FAM-Labeled CGY-Peptide by hCMEC/D3 Cells

(55) To evaluate the role of the transferrin receptor in the uptake of FAM-CGY nanoparticles, hCMEC/D3 cells were incubated with both transferrin and FAM-CGY nanoparticles in competition experiment (FIG. 15).

(56) The determination of fluorescence peptide internalization in hCMEC/D3 cells by flow cytometry (FACS) was performed as follows. Cells (2×10.sup.4/cm.sup.2) were seeded on 24-well plate (Corning, N.Y.) and grown 2 days at 37° C. and 5% CO.sub.2 in order to reach 60%-70% confluency. The cells were washed 3 times with pre-heated PBS and 200 μL of 5 μM fluorescence-labelled peptides (diluted in cell medium containing serum) was added. After 24 h of incubation at 37° C. with 5% CO.sub.2, each chamber was washed with pre-heated PBS 3 times and incubated with fresh cell growth medium. The cell nucleus was stained with Hoechst 34580 dye (5 ug/mL), cell membrane was stained with Texas Red®-X wheat germ agglutinin (5 ug/mL). FAM-CGY nanoparticles competed with different concentrations of transferrin or added with the peptides in different concentrations ranging from 62.5-500 nM and were analyzed by fluorescence microscopy and quantified by FACS.

(57) The live cell imaging was performed on a widefield microscope (Leica AF6000LX, Germary) using a 63× oil objective with 1.6 magnification and filters GFP (Ex BP 470/40, Em BP 525/50), Cy3 (Ex BP 555/25, Em BP 605/52) and A4 (Ex BP 360/40, Em 470/40). Treated cells were then washed 3 times with pre-warmed PBS, and harvested by trypsinization. A total of 10,000 cells were analyzed by flow cytometry (FACS Array™ Cell Analysis, BD, USA).

(58) The competition experiment shows that the uptake of the FAM-CGY nanoparticles is significantly decreased with increasing transferrin concentration suggesting that FAM-CGY nanoparticles strongly compete with transferrin on binding to the transferrin receptor.

Example 3: Specific Binding and Cellular Uptake of FAM-Labeled CGY-Peptide to hCMEC/D3 Cells

(59) To evaluate the role of the RAGE in the uptake of FAM-CGY nanoparticles, hCMEC/D3 cells were co-treated with RAGE-peptide or amyloid-β and FAM-CGY nanoparticles in competition experiments (FIG. 17).

(60) The determination of fluorescence peptide internalization in hCMEC/D3 cells by flow cytometry (FACS) was performed as follows. Cells (2×10.sup.4/cm.sup.2) were seeded on 24-well plate (Corning, N.Y.) and grown 2 days at 37° C. and 5% CO.sub.2 in order to reach 60%-70% confluency. The cells were washed 3 times with pre-heated PBS and 200 μL of 5 μM fluorescence-labelled peptides (diluted in cell medium containing serum) was added. After 24 h of incubation at 37° C. with 5% CO.sub.2, each chamber was washed with pre-heated PBS 3 times and incubated with fresh cell growth medium. The cell nucleus was stained with Hoechst 34580 dye (5 ug/mL), cell membrane was stained with Texas Red®-X wheat germ agglutinin (5 ug/mL). FAM-CGY nanoparticles (5 μM) competed with different amounts of RAGE-peptide or amyloid-β peptide (5, 10 or 20 μg) and were analyzed by fluorescence microscopy (data not shown) and quantified by FACS (FIG. 17).

(61) The live cell imaging was performed on a widefield microscope (Leica AF6000LX, Germary) using a 63× oil objective with 1.6 magnification and filters GFP (Ex BP 470/40, Em BP 525/50), Cy3 (Ex BP 555/25, Em BP 605/52) and A4 (Ex BP 360/40, Em 470/40). Treated cells were then washed 3 times with pre-warmed PBS, and harvested by trypsinization. A total of 10,000 cells were analyzed by flow cytometry (FACS Array™ Cell Analysis, BD, USA).

(62) The competition experiment shows that the uptake of the FAM-CGY nanoparticles is significantly decreased with increasing RAGE-peptide or amyloid-β concentration suggesting that FAM-CGY nanoparticles strongly compete with the RAGE-peptide and amyloid-β on binding to the RAGE receptor.

Example 4: TFRC Gene Knock-Out Experiments

(63) The transferrin receptor (TFRC) expression was downregulated by using a commercial transfection reagent siPORT Amine/TFRC siRNA complex to study the possible blockage of the FAM-CGY nanoparticle uptake in hCMEC/D3 cells. The commercial transfection reagent siPORT Amine/TFRC siRNA complex was incubated for 72 h in hCMEC/D3 cells including an unspecific siRNA (siControl) as control. The TFRC low expression cells and siControl transfection cells were incubated with 5 μM FAM-CGY nanoparticles and 62.5 nM transferrin (positive control) for 16 h, respectively. The FAM-CGY nanoparticles and transferrin uptake was detected by fluorescence microscopy (not shown) and FACS (FIG. 16).

(64) FAM-CGY nanoparticle uptake is markedly reduced in TFRC knocked out hCMC/DE3 cells to nearly the same level the as transferrin uptake. Hence, TFRC functions as a receptor for FAM-CGY nanoparticle binding and uptake.

Example 5: RAGE Gene Knock-Out Experiments

(65) The RAGE expression was downregulated by using a commercial transfection reagent siPORT Amine/RAGE siRNA complex to study the possible blockage of the FAM-CGY nanoparticle uptake in hCMEC/D3 cells. The commercial transfection reagent siPORT Amine/RAGE siRNA complex was incubated for 72 h in hCMEC/D3 cells including an unspecific siRNA (siControl) as control. The TFRC low expression cells and siControl transfection cells were incubated with 5 μM FAM-CGY nanoparticles and 250 nM amyloid-β (positive control) for 16 h, respectively. The FAM-CGY nanoparticles and RAGE peptide uptake was detected by fluorescence microscopy (not shown) and FACS (FIG. 18).

(66) FAM-CGY nanoparticle uptake is markedly reduced in RAGE knocked out hCMC/DE3 cells to nearly the same level as amyloid-β uptake. Hence, RAGE functions as a receptor for FAM-CGY nanoparticles.

Example 6: Formation of siRNA/FAM-CGY Complex

(67) Different molar rates of siRNA were added to the FAM-CGY peptide solution (50 μM/L) dropwise in saline solution and incubated for 30 min. Then the mixture solution was diluted with serum free hCMEC/D3 cell medium to a final peptide concentration 5 μM. The atomic force microscopy (AFM) (FIG. 22A), nanoparticle tracking analysis (NTA) (FIG. 22B), fluorescence microscopy (not shown), dynamic light scattering (DLS) technology (not shown) and transmission electron microscopy (TEM) (FIG. 23) were employed to characterize the siRNA/FAM-CGY complex. Complexes with circular RNA (ciRNA) and FAM-CGY was also studied using TEM (FIG. 24). Briefly, one drop of the final Cy3-siRNA/FAM-CGY solution was added on microscope glass slides (VWR) and left to air-dry at room temperature for 30 min. The Cy3-siRNA/FAM-CGY complexes were imaged by fluorescent microscopy (Leica AF6000LX, Germany) using a 100× TIRF oil objective with 1.6 magnification and filters GFP (Ex BP 470/40, Em BP 525/50), and Cy3 (Ex BP 555/25, Em BP 605/52). The size and surface charge of FAM-CGY peptidic nanoparticles and siRNA/FAM-CGY complex were investigated using a Zetasizer Nano ZS goniometer (Malvern Instruments, Malvern, UK) containing a He-Ne laser source (λ=633 nm, 22 mW output power). All the measurements were carried out at 25° C. Three measurements each with 30 sub-runs were performed for each sample and results are shown in Table 2.

(68) FAM-CGY forms stable spherical and rod shaped nanoparticles with siRNA having average diameter of 168±12 nm for spherical particles analyzed by NTA and for fibres a length of 297±87 nm analysed by TEM 23), which is slightly larger than FAM-CGY nanoparticles described above. These results are similar to dynamic light scattering (DLS) characterization, where the siRNA/FAM-CGY particles are in the size range of 170-180 nm and display a slightly positive surface charge with zeta potentials ranging from 5.57±0.87 to 1.27±0.38 mV.

(69) Table 2. The size and zeta potential of FAM-CGY nanopaticles and siRNA/FAM-CGY complexes characterized by dynamic light scattering (DLS).

(70) TABLE-US-00002 Zeta potential Samples Size (nm) PDI (mV) 5 μM FAM-CGY 156.6 ± 2.1  0.325 ± 0.028 7.27 ± 0.73 nanopartilces 8 nM siRNA/5 μM 170.2 ± 5.3  0.380 ± 0.033 5.57 ± 0.87 FAM-CGY complex 16 nM siRNA/5 μM 173.8 ± 3.2  0.402 ± 0.047 2.87 ± 0.50 FAM-CGY complex 24 nM siRNA/5 μM 180.6 ± 12.1 0.397 ± 0.054 1.27 ± 0.38 FAM-CGY complex

Example 7: Transfection of hCMC/DE3 Cells with Cy3-siRNA/FAM-CGY Complex

(71) To confirm the rate of cellular transfection, different molar ratios of Cy3-fluorescence labeled siRNA (Cy3-siRNA) were incubated with FAM-CGY peptide to form polyplexes, and added to hCMEC/D3 cells (data not shown). Different molar rates of Cy3-siRNA were added to FAM-CGY peptide dropwise in saline solution and incubated for 30 min. Then the mixture solution was diluted with normal hCMEC/D3 cells medium to a final concentration of FAM-CGY peptide 5 μM (5000 nM). The cells were incubated with different rates of Cy3-siRNA/FAM-CGY complex as indicated at 37° C. for 24 h. The cell nucleus was labelled with Hoechest 33342 (blue), insert bars=50 μm.

(72) The Cy3-siRNA/FAM-CGY complex exhibits significant cellular uptake by hCMEC/D3 cells in all molar ratios compared to Cy3-siRNA alone.

Example 8: Transfection of hCMC/DE3 Cells with Cy3-siRNA/FAM-CGY Complex

(73) The siRNA efficacy was investigated by subjecting hCMEC/D3 cells to functional TFRC siRNA/FAM-CGY complexes (FIG. 23).

(74) The intracellular distributions of siRNA complexed with the FAM-CGY nanoparticles were observed by fluorescent microscopy using Cy3-fluorescence labeled siRNA. In vitro gene silencing experiments were performed in hCMEC/D3 cells using the TFRC siRNA and a scrambled siRNA as a negative controls. The level of TFRC expression in hCMEC/D3 cells treated with different siRNA/FAM-CGY formulations were investigated by western blot.

(75) Cells treated with the scrambled siRNA complexes do not give rise to any significant gene silencing even when using up to 24 nM siRNA mixed with FAM-CGY or siPORT Amine (Amine). In contrast, TFRC gene expression is slightly reduced by TFRC siRNA/FAM-CGY complexes containing 8 nM siRNA. When using TFRC siRNA up to 24 nM, the TFRC siRNA/FAM-CGY complexes efficiently inhibit TFRC gene expression down to 32.4% after 72 h of transfection. The siRNA/FAM-CGY delivery system showed a better silencing efficiency than siRNA/Amine which leads to 45.5% TFRC knockdown. Moreover, the siRNA/FAM-CGY complex transfection is time dependent. After 24 hours and 48 hours, only 20% gene expression knockdown is detected, while after 72 hours significantly more knockdown is observed.

Example 9: Cytotoxicity of Cy3-siRNA/FAM-CGY

(76) The cytoxicity of FAM-CGY peptide and siRNA/FAM-CGY complex was evaluated by lactase dehydrogenase (LDH) assay (FIG. 26). The hCMEC/D3 cells were incubated with different concentrations of the peptide (from 1 to 20 μM) and different formulations of siRNA/FAM-CGY complexes for 24 h. The viability of cells without treatment was used as a control. The LDH assay has means of measuring the membrane integrity as a function of the amount of cytoplasmic LDH leaked into the medium. Compared to the control in FIG. 26A, the LDH leakage in the medium for the groups treated with different concentrations of the peptide did not significantly increase. Thus, there were no significant differences observed between the groups treated with FAM-CGY, FAM-d-CGY and CGY-FAM. A 30% LDH leakage was observed in cells treated with siRNA/Amine group, indicated that it was more toxic than the siRNA/FAM-CGY complexes.

(77) These results indicate that there is no significant cytotoxicity observed for the FAM-CGY peptide or the siRNA/FAM-CGY complexes.

Example 10: Light-Triggered Release siRNA

(78) To evaluate the intracellular release of siRNA loaded on FAM-CGY nanoparticles by illumination, Cy3-siRNA was complexed with FAM-CGY at molar ratio of 1:200 (Cy3-siRNA: FAM-CGY) in 50 μL saline at a concentration of 20 μM FAM-CGY. After 30 min incubation, the Cy3-siRNA/FAM-CGY complex was diluted with 150 μL 5% FBS cell medium to a final concentration of 5 μM FAM-CGY. hCMEC/D3 cells were seeded in 8-well Lab-Tek chamber slides (Nunc, Naperville, Ill.) (2×10.sup.4/cm.sup.2) and grown for 24 h. The cells were then washed with pre-warm PBS and treated with 200 μL complexes. After 24 h of incubation, the nuclei was stained with Hoechest 33342 (5 μg/mL) for 10 min and cells were rinsed three times with pre-warmed PBS. The cells were irradiated with the 488 nm light at different time points 0, 2, 2.30, 4 or 6 minutes passed through the 63× objective lens, and the images were each recorded at 30 s by fluorescent microscopy using filters GFP (Ex BP 470/40, Em BP 525/50), Cy3 (Ex BP 555/25, Em BP 605/52) and A4 (Ex BP 360/40, Em 470/40), respectively. The fluorescence intensity of the FAM-CGY peptide, Cy3-siRNA and Hoechest 33342 (nucleus) in the cytoplasm along specific area were quantified by software LAS AF Lite 6.0 (Leica, Germany) (FIG. 29).

(79) FAM-CGY is released from internalized vesicles after between 2.5 and 4 minutes of light exposure.

Example 11: Preparation of Liposomes

(80) F-Liposomes consisting of phospholipids, cholesterol, and functionalized coupling lipid (MPB-PE) at a molar ratio of DPPC:Cholesterol:DSPE-PEG:DSPE-PEG-MPB at a ratio of 7:2.5:0.025:0.025 were produced from lipid films hydrated with PBS. The final concentration was 10 μmol lipid/ml buffer. The hydration was performed in a water bath at 56° C. for 30 min. The resulting multilamellar vesicles were extruded (LiposoFast Extruder) 21 times through a polycarbonate filter (Avanti) with a pore size of 100 nm. The liposome size was determined by NanoSight LM20 (NanoSight, Amesbury, United Kingdom). Liposomes were labeled with red fluorescent phospholipid (16:0 Liss Rhod PE [1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (ammonium salt)]) or green fluorescent phospholipid (18:1 PE CF [1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(carboxyfluorescein) (ammonium salt)]).

(81) Coupling Peptides to Liposomes

(82) Peptides (CGY-peptide or GYR-GYR-peptide (that is a dimer of CGY-peptide)) were reduced using 2 mM Bond-Breaker TCEP (Pierce) under Nitrogen atmosphere for 1 h at 37° C. After gel filtration using a sepharose CL-4B column, for removing TCEP. Reduced peptide was incubated with preformed maleimide-containing liposomes (The molar ratio of phospholipids to peptide was 1 μmol to 1 nmol) under nitrogen atmosphere overnight at room temperature. Unreacted maleimide groups were inactivated by incubation with 0.5 mM cysteine for 30 min at room temperature. For removing non-conjugated peptides the mixture was centrifuged 3 times at 75.000 rpm for 30 min at 4° C. and the resuspended in PBS. Then the phospholipid concentration was again measured, and for indirectly measuring the amount of peptides that has been bond to the liposomes, the peptide concentration in supernatant was measured by Bradford assay method. Conjugated liposome was characterized by SDS-PAGE and measuring the size by NanoSight instrument.

(83) Uptake Study of Conjugated Peptides by FACS

(84) The cells used were human adult brain endothelial cell line hCMEC/D3 were grown in endothelial growth medium 2 (EGM-2, Lonza, UK) supplemented with fetal bovine serum (FBS) 5%, hydrocortisone 1.4 μM, basic fibroblast growth factor 1 ng/mL, penstrep 1% and HEPES 10 nM in 24 well tissue culture plates. The cells were used at 70% confluence (corresponding cells to 6×10.sup.4 to 8×10.sup.4 cells) were incubated with liposomes labeled with 0.2 μmol RED or GREEN fluorescently-tagged phospholipid (F-liposomes) and bearing the peptide conjugate or liposomes attached to fluorescent CGY or scrambled CGY (e.g., FAM-CGY, CGY-FAM and FAM-CGY Scrambled 2). Liposomes were added to the cells (in 200 μL medium) and after overnight incubation the cells were washed with 1% BSA in PBS then detached from cell culture dishes using trypsin (Sigma-Aldrich, Inc). The cells were analyzed by flow cytometry (FACS Calibur, Becton Dickinson) (FIG. 39).

(85) F-Liposome and FAM linked to CGY-peptide or GYR-GYR-peptides in any position bind to hCMEC/D3 cells in a greater number than the control and F-Liposome alone.

Example 12: Double Peptide FAM-GYR-GYR Experiments

(86) The different cellular uptake of FAM-CGY and FAM-GYR-GYR peptides in hCMEC/D3 cells was investigated by flow cytometry (FACS). hCMEC/D3 cells (2×10.sup.4/cm.sup.2) were seeded on 24-well plate (Corning, N.Y.) and grown 2 days at 37° C. and 5% CO.sub.2 in order to reach 60%-70% confluency. The cells were washed 3 times with pre-heated PBS. The peptide uptake experiments were initiated by adding 200 μL of a range of FAM-CGY and FAM-GYR-GYR in different concentrations (1-10 μM/L, diluted in cell medium containing serum). The double peptide contains the sequence Gly-Tyr-Arg-Pro-Val-His-Asn-Ile-Arg-Gly-His-Trp-Ala-Pro-Gly-Gly-Gly-Tyr-Arg-Pro-Val-His-Asn-Ile-Arg-Gly-His-Trp-Ala-Pro- Gly (SEQ ID NO.2) and optionally has an N-terminal cysteine residue.

(87) After 24 h incubation at 37° C. with 5% CO.sub.2, each chamber was washed with pre-heated PBS 3 times, and harvested by trypsinization. A total of 10,000 cells were analyzed by flow cytometry (FACS Array™ Cell Analysis, BD, USA) (FIG. 35).

(88) FAM-GYR-GYR peptide/structures show considerably higher uptake by hCMEC/D3 cells compared with FAM-CGY peptide at all tested concentrations. The double peptide shows excellent target binding, even increased when compared with the single sequence and allows for delivery of larger molecules (e.g., DNA). Trials illustrated utilized a double peptide with a glycine residue between the two peptide sequence elements but other amino acid linkers, or other non-amino acid linker molecules can be used to create such a molecule.

Example 13: Transfection of Cy3-siRNA/FAM-GYR-GYR Complex on hCMEC/D3 Cells

(89) Cy3-siRNA was complexed with FAM-GYR-GYR at a molar ratio of 1:200 (Cy3-siRNA: FAM-CGY) in 50 μL saline at a concentration of 20 μM/L FAM-GYR-GYR. After 30 min incubation, the Cy3-siRNA/FAM-GYR-GYR complex was diluted with 150 μL 5% FBS cell medium to a final concentration of 5 μM/L FAM-GYR-GYR. hCMEC/D3 cells were seeded in 8-well Lab-Tek chamber slides (Nunc, Naperville, Ill.) (2×10.sup.4/cm.sup.2) and grown for 24 h. The cells were then washed with pre-warm PBS and treated with 200 μL Cy3-siRNA/FAM-GYR-GYR complexes. After 1 or 4 h of incubation, the nuclei was stained with Hoechest 33342 (5 μg/mL) for 10 min and cells were rinsed three times with pre-warmed PBS. Finally, the cells were observed with a Leica fluorescent microscopy (Leica AF6000LX, Germary) using a 63× TIRF oil objective and filters GFP (Ex BP 470/40, Em BP 525150), Cy3 (Ex BP 555/25, Em BP 605/52) and A4 (Ex BP 360/40, Em 470/40), respectively (FIG. 36).

(90) This trial demonstrates that Cy3-siRNA/FAM-GYR-GYR complex internalizes into hCMEC/D3 cells.

Example 14: Binding a Hydrophobic Moiety to a Peptide-Formed Nanoparticle

(91) Caprylic acid conjugated CGY peptide (Caprylic-CGY) was synthesized by a solid phase method. Peptides were purified by preparative HPLC and characterized by analytical HPLC and mass spectrometry (M.sub.w=1946.29, Purity: 98.26%). The lyophilized peptides were dissolved into dimethyl sulfoxide (DMSO) with a peptide concentration of 500 μM and stored at −80° C. For the self-assembly, the 500 μM stock solution of Caprylic-CGY was diluted into MQ water with the final concentration of 5 μM and incubated at room temperature for 1 h. The size of self-assembly of Caprylic-CGY was performed by Nanoparticle Tracking Analysis (NTA) (LM20, NanoSight, Amesbury, United Kingdom) with a sample chamber with a 405 nm blue laser and a Viton fluoroelastomer O-ring. As seen in FIG. 41, The mean size of self-assembly is 117±74 nm and with a mode of 86 nm.

Example 15: Rhodamine as a Drug or Fluorescent Molecule Attached to a Peptide

(92) Peptidic complexes were formed by drop addition of cargoes (FAM-(C)-NAP, FAM-GYR, FAM-NAP, FAM) to 80 μM rhodamine-conjugated CGY peptide (Rh-CGY) or 80 μM CGY peptide (Table X) in MilliQ (MQ) water with equatable liquid volume and incubated for 60 min. The mixture was diluted with MQ water to a final Rh-CGY or CGY peptide concentration of 10 μM. The peptidic complexes were characterized by NTA for size and electron microscopy (EM) for mophology. Western blot was also employed to detect disulfide bond, which form between the cargo and Rh-CGY peptide or CGY peptide. Briefly, the peptide or complex samples were loaded on 10% Bis-Tris mini gels (Invitrogen, CA, USA) and subjected to electrophoresis. The separated samples were electrophoretically transferred to PVDF membranes by use of an iBlot™ Gel Transfer Device (Life Technologies, USA). Membranes were blocked for 1 h at room temperature in 3% BSA/TBST (137 mM Sodium Chloride, 20 mM Tris, 0.1% Tween-20, pH 7.6), and incubated over night at 4° C. with HRP-Goat anti-Fluorescein antibody (diluted 1:1000 in 2% BSA/TBST). For detection, membranes were incubated with Novex® ECL Chemiluminescent Substrate Reagent Kit (Invitrogen, CA, USA).

(93) Delivery peptide to hCMEC/D3 cells. In vitro delivery experiments were performed in hCMEC/D3 cells. Briefly, the peptidic complexes were firstly prepared with concentration of 80 μM Rh-CGY or 80 μM CGY peptide, and diluted with cell medium to 10 μM Rh-CGY or CGY peptide. The complex solutions were added to hCMEC/D3 cells following 24 h incubation. Live cell images were obtained by widefield microscopy, and the intercellular fluorescence intensity was quantified by FACS.

(94) To investigate the effect of hydrophobic block FAM in peptide self-assembly, another fluorophore Rhdomine B was choose to conjugate with CGY peptide in the N-terminal, which termed Rh-CGY (molecular mass 2244.69 g/mol). The measurement of NTA indicated that the Rh-CGY can also easily self-assembly. FIG. 41A represents the size distribution of Rh-CGY supermolecular with narrow peak and a weak trailing fraction. The average size of Rh-CGY supermolecular was 131±60 nm with a modal size of 94 nm (FIG. 41A). Also the supermolecular of Rh-CGY can efficiently enter the hCMEC/D3 cells (FIG. 41B). In order to investigate the functionality of Rh-CGY peptide, a model cargo of FAM-(C)-NAP peptide was selected to co-assemble with Rh-CGY peptide. From the Western blot data, FAM-(C)-NAP peptide form disulfide bond with Rh-CGY peptide (FIG. 42). The lanes of the Western blot are as follows: Lane 1: Rh-CGY peptide, Lane 2: FAM-(C)-NAP peptide, Lane 3: CGY peptide, Lane 4: FAM-GYR peptide, Lane 5: Rh-CGY/FAM-(C)-NAP peptidic complex, Lane 6: Rh-CGY/FAM-GYR peptidic complex, Lane 7: CGY/FAM-(C)-NAP peptidic complex.

(95) Because of this disulfide bond and the π-π interaction between the fluorophore of FAM and Rhodamine, the FAM-(C)-NAP peptide can form stable complex with Rh-CGY peptide. The average size is 99±41 nm (FIG. 43A). The mixture of Rh-CGY and FAM-(C)-NAP self-assembled into not only the nanoparticles but also into fibres based on the EM observation (FIG. 43B). With the assistance of Rh-CGY peptide, the FAM-(C)-NAP peptide can be easily delivered into hCMEC/D3 cells (FIGS. 43C, 43D, and 43E). When FAM-(C)-NAP peptide mixed with CGY peptide, it can also form a disulfide bond with CGY peptide (FIG. 42).

(96) However, this mixture cannot form any particles and the mixture of FAM-(C)-NAP and CGY peptide cannot deliver FAM-(C)-NAP peptide into cells (FIG. 43C). When cysteine amino acid was deleted from the sequence of the FAM-(C)-NAP peptide, FAM-NAP peptide was poorly taken up by hCMEC/D3 cells (FIG. 43C). When it was co-incubated with Rh-CYG peptide, it did not form disulfide bond with Rh-CGY peptide. FAM-NAP peptide did not efficiently cross cell membrane even after co-incubated with Rh-CGY peptide (FIG. 43C). These observations indicated that forming disulfide bond is one of key factor to delivery FAM-(C)-NAP peptide into the cells. This can be most readily accomplished with the inclusion of a cysteine residue, and such inclusion can be at many different points of the sequence, including at the N-terminus, at the C-terminus, or internally.

(97) In another case, FAM-GYR peptide can form stable particles/fiber complex with Rh-CGY peptide with the mean size of 82±43 nm (FIGS. 44A and 44B). FAM-GYR peptide trapped in Rh-CGY peptide was significantly delivered into hCMEC/D3 cells compared with FAM-GYR peptide alone (FIGS. 44C and 44D). The FAM-GYR peptide does not contain the cysteine, and cannot form disulfide bond to cross link with Rh-CGY peptide (FIG. 42). But the main sequence of FAM-GYR was the same with Rh-CGY peptide, the amino acid in FAM-GYR and Rh-CGY peptide, such as Arg, Trp, can interact with each other to form hydrogen bond and π-π interaction. This result demonstrated that the Rh-CGY/FAM-GYR peptidic mixture can self-assemble into stable complexes even without the disulfide bond (FIGS. 44A and 44B). Cells were labelled with Hoechest 33342 (blue).

(98) To further prove this concept, the fluorophore FAM alone was co-incubated with the Rh-CGY peptide. FAM can not been entrapped in the Rh-CGY peptidic complexes. The mixture of FAM and Rh-CGY peptide can not enhance the uptake of FAM in hCMEC/D3 cells (FIG. 43C). This suggests that the sequence of FAM-GYR peptide is specific to form stable particles with Rh-CGY peptide and improve the uptake in hCMEC/D3 cells. Rh-CGY peptide can co-assemble with the cargo peptide with specific properties to fabricate stable nanoparticle/fiber complex because of forming disulfide bond or hydrogen bond and π-π interaction, and deliver the cargo peptide into hCMEC/D3 cells. Rh-CGY peptide is a potential candidate of peptidic-based delivery system for the CNS disease.

Example 16: Plasmid Transfection Mediated by Double Peptide

(99) To evaluate double peptide (DP)-mediated gene transfection, different concentrations of DP and constant amounts of pcDNA3.1 NT-GFP expression plasmid (0.3 μg) (the peptide/DNA change ration of 1:10, 1:20 and 1:40 were investigated in this study) were mixed into 50 μL serum free media, and complexes were formed for 1 h at room temperature, after which another 150 μL serum free media was added (total volume of peptide/DNA complex was 200 μL). The cultured hCMEC/D3 cells (2×10.sup.4 cells) were overlaid with 200 μL peptide/DNA complex, followed by incubation for 4 h at 37° C. in 5% CO.sub.2 atmosphere. The cultures were then a washed once with serum-free media and transferred to complete media containing 5% serum for growth. After 48 h, GFP gene expressions were monitored by fluorescence microscopy. Lipofectamine® 2000-mediated transfections were performed as described by the manufacturer's protocol (Life Technologis, CA, USA).

(100) Since the double peptide (DP) has four positive charge amine acids in each peptide molecular, it is possible for DP to bind with DNA by electrostatic interaction and form stable complex. In order to test the possibility of DP-mediated gene delivery, DP was mixed with plasmid DNA encoding GFP in different charge ratios from 10:1 to 40:1. Transfection was performed with different peptide/DNA charge ratios in hCMEC/D3 cells, and transfection efficiencies were evaluated using fluorescence microscopic analysis of GFP expression. The results showed that DP was able to mediate translocation of plasmids into cells when the charge ratios of peptide/DNA more than 20 (FIG. 45). And the transfection efficiency of peptide/DNA with charge ratio 40:1 was comparable with commercial tansfection reagent Lipofectamine® 2000 based on the intensity of fluorescence microscopy signal. But compared with the DP, the Lipofectamine® 2000, the cationic lipid based gene delivery system, can lead to higher cytotoxicity. The results indicated that the DP is a potential safe delivery system of plasmid for brain targeting. Cells were labelled with Hoechest 33342 (blue).

Example 17: Targeting of the Brain In Vivo

(101) BALB/c nude mice received 5 μM of FAM-CGY peptide or 10 μM of Rh-CGY peptide (the final concentration in blood) intravenously and subjected to optical imaging at various time points post-injection. The in vivo fluorescence imaging was performed using the IVIS Imaging System 200 Series and analyzed using the IVIS Living Imaging 3.0 software (Caliper Life Sciences, Alameda, Calif., USA). Optimized GFP filter or Dsred filter sets were used for acquiring FAM-CGY or Rh-CGY peptide fluorescence in vivo, respectively. After the whole body mice images were recorded, the mice were sacrificed and the organs were dissected and subjected to ex vivo fluorescence imaging. Data in FIG. 46 shows brain targeting of the described invention as well as localization to organs of the reticuloendothelial system (liver, spleen). Kidney accumulation may represent single chain conjugates (since they are in equilibrium with nanoparticles). Some lung accumulation also occurs (not shown).

Example 18: Sections of Brain in Peptide-Injected Mouse

(102) Organs were fixed in a PBS solution of 4% paraformaldehyde overnight. After that, samples were placed in 15% sucrose PBS solution for 12 h, which was then replaced with 30% sucrose for 24 h. The samples were then embedded in Tissue Tek O.C.T. compound (Mc Cormick, USA) and frozen at −60° C. in isopentane. Frozen sections, 7 mm thick, were then prepared with a cryotome and stained with 10 μg/mL DAPI for 10 min. After PBS washing, the sections were observed under a fluorescence microscope. The results in FIG. 47 show fluorescent signals in the brain tissue, with green coloration representing the labeled peptide and blue being DAPI.

Example 19: Imaging of Peptide Conjugate Aggregate Structures

(103) Atomic force microscopy (AFM) analysis of FAM-CGY revealed the presence of a heterogeneous nanoparticle and ‘nanoparticle-fibre’ network system, where some nanoparticles intercept fibres or are cross-linked by the fibres (FIG. 48A). Nanoparticle may be perceived as nucleation sites where several ‘nanofibre-like’ structures of variable dimensions and height emerge. Due to the heterogeneous nature of the network, nanoparticle tracking analysis (NTA) was employed for possible size distribution determination and counting of the observed species in the nanoparticle and ‘nanoparticle-fiber’ network system.

(104) Transmission electron microscopy (TEM) investigation of the ‘nanoparticle-fibre’ network showed that the ‘spherical-like’ structures are of ‘core-shell’ morphology (FIGS. 48C through 48G). The core component (FIG. 4A1) is most likely an assembly of condensed unimers, dimers and/or oligomers of different arrangements (e.g., dimers with anti-parallel arrangements) and amenable to further growth through multiple interactive forces, which eventually forms elongated ‘hair-like’ projections of the shell component (FIGS. 4A3, 4B1, 4B2). Different nanofibre network morphologies, predominantly of twisted elongated architectures emanating from the shell component of the ‘core-shell’ structures, are visible (FIGS. 48C, 48E-48G).