A ferumoxytol-based dual-modality imaging probe for long-term stem cell tracking through MRI and early diagnosis of cell apoptosis through simultaneous fluorescence imaging is provided. Specifically, a ferumoxytol-based dual-modality imaging probe is provided with enhanced T.sub.2* relaxivity for tracking stem cells through magnetic resonance imaging and detecting apoptotic stem cells through fluorescence imaging.

Microfluidic organ-on-a-chip devices have been developed with the aim to replicate human tissues in vitro. However, there is no option to quantitatively monitor biological processes that take place within the chip, over time. Destructive methods in order to analyze, tissue formation, gene expression, protein secretion etc. require the harvest of the tissue at a certain time point. Described herein are methods and compositions for non-destructive molecular imaging methods and systems in order to quantitatively monitor specific biological processes, over time, within the chip, without the need to harvest.

Microfluidic organ-on-a-chip devices have been developed with the aim to replicate human tissues in vitro. However, there is no option to quantitatively monitor biological processes that take place within the chip, over time. Destructive methods in order to analyze, tissue formation, gene expression, protein secretion etc. require the harvest of the tissue at a certain time point. Described herein are methods and compositions for non-destructive molecular imaging methods and systems in order to quantitatively monitor specific biological processes, over time, within the chip, without the need to harvest.

Blood-brain barrier permeable peptide compositions that contain variable antigen binding domains from camelid and/or shark heavy-chain only single-domain antibodies are described. The variable antigen binding domains of the peptide compositions bind to therapeutic and diagnostic biomarkers in the central nervous system, such as the amyloid-beta peptide biomarker for Alzheimer's disease. The peptide compositions contain constant domains from human IgG, camelid IgG, and/or shark IgNAR. The peptide compositions include heavy-chain only single-domain antibodies and compositions with one or more variable antigen binding domain bound to one or more constant domains.

Disclosed herein, inter alia, are methods for detecting cancer using nanoparticles.

Microfluidic organ-on-a-chip devices have been developed with the aim to replicate human tissues in vitro. However, there is no option to quantitatively monitor biological processes that take place within the chip, over time. Destructive methods in order to analyze, tissue formation, gene expression, protein secretion etc. require the harvest of the tissue at a certain time point. Described herein are methods and compositions for non-destructive molecular imaging methods and systems in order to quantitatively monitor specific biological processes, over time, within the chip, without the need to harvest.

The present invention provides compositions and methods of use of nanoparticle-based probes for in vivo imaging and therapy. The probes can be used to track diseased target cells by non-invasive imaging in the near-infrared range. Additionally, the probes can induce cell death of the target cells via photodynamic treatment.

Blood-brain barrier permeable peptide compositions that contain variable antigen binding domains from camelid and/or shark heavy-chain only single-domain antibodies are described. The variable antigen binding domains of the peptide compositions bind to therapeutic and diagnostic biomarkers in the central nervous system, such as the amyloid-beta peptide biomarker for Alzheimer's disease. The peptide compositions contain constant domains from human IgG, camelid IgG, and/or shark IgNAR. The peptide compositions include heavy-chain only single-domain antibodies and compositions with one or more variable antigen binding domain bound to one or more constant domains.

Microfluidic organ-on-a-chip devices have been developed with the aim to replicate human tissues in vitro. However, there is no option to quantitatively monitor biological processes that take place within the chip, over time. Destructive methods in order to analyze, tissue formation, gene expression, protein secretion etc. require the harvest of the tissue at a certain time point. Described herein are methods and compositions for non-destructive molecular imaging methods and systems in order to quantitatively monitor specific biological processes, over time, within the chip, without the need to harvest.

Provided herein are block copolymers comprising a hydrophilic polymer segment and a hydrophobic polymer segment, wherein the hydrophilic polymer segment comprises a polymer selected from the group consisting of: poly(ethylene oxide) (PEO), poly(methacrylate phosphatidyl choline) (MPC), and polyvinylpyrrolidone (PVP), wherein the hydrophobic polymer segment comprises

##STR00001##

wherein R is H or CH.sub.3, wherein R is NR.sup.1R.sup.2, wherein R.sup.1 and R.sup.2 are alkyl groups, wherein R.sup.1 and R.sup.2 are the same or different, wherein R.sup.1 and R.sup.2 together have from 5 to 16 carbons, wherein R.sup.1 and R.sup.2 may optionally join to form a ring, wherein n is 1 to about 10, and wherein x is about 20 to about 200 in total. Also provided are pH-sensitive micelle compositions for therapeutic and diagnostic applications.