The invention relates to a device for correlative scanning transmission electron microscopy (STEM) and light microscopy. In order to create a device for correlative microscopy which enables an improved combination of light microscopy and STEM methods, a STEM detector (7) according to the invention is combined with a photo-optical lens (8). This detection device combines the efficient detection by means of STEM microscopy of materials having a high atomic number, for example specific nanoparticle markers in a specimen in a liquid, such as a cell, with simultaneous light microscopy.

An aqueous approach to synthesize capped SnS quantum dots (QDs) followed by optional capping molecule extension by attaching one or more extending molecules to the capping molecule via peptide bond formation at elevated temperature. The capped SnS QDs may have a capping molecule:Sn:S molar ratio of 16:3:1 to 16:12:1. A suspension of SnS QDs was heat-treated at 200 C. for 0.5-4 hrs. The obtained SnS QDs showed an NIR emission peak at 820-835 nm with an excitation wavelength at 690 nm. The as synthesized SnS QDs were found to have high positive zeta potential of 30 mV and thus were toxic to cells. By neutralizing the SnS QDs the cytotoxicity was reduced to an accepted level. The heat-treatment step can be obviated by adding a glycerol solution containing S.sup.2 anions and capping molecule to a glycerol solution of Sn.sup.2+ ions.

The present invention relates to a core/shell nanoplatelet and its use as a fluorophore or a fluorescent agent.

An aqueous approach to synthesize capped SnS quantum dots (QDs) followed by optional capping molecule extension by attaching one or more extending molecules to the capping molecule via peptide bond formation at elevated temperature. The capped SnS QDs may have a capping molecule:Sn:S molar ratio of 16:3:1 to 16:12:1. A suspension of SnS QDs was heat-treated at 200 C. for 0.5-4 hrs. The obtained SnS QDs showed an NIR emission peak at 820-835 nm with an excitation wavelength at 690 nm. The as synthesized SnS QDs were found to have high positive zeta potential of 30 mV and thus were toxic to cells. By neutralizing the SnS QDs the cytotoxicity was reduced to an accepted level. The heat-treatment step can be obviated by adding a glycerol solution containing S.sup.2 anions and capping molecule to a glycerol solution of Sn.sup.2+ ions.

The present invention provides a fluorescent silica-based nanoparticle that allows for precise detection, characterization, monitoring and treatment of a disease such as cancer. The nanoparticle has a range of diameters including between about 0.1 nm and about 100 nm, between about 0.5 nm and about 50 nm, between about 1 nm and about 25 nm, between about 1 nm and about 15 nm, or between about 1 nm and about 8 nm. The nanoparticle has a fluorescent compound positioned within the nanoparticle, and has greater brightness and fluorescent quantum yield than the free fluorescent compound. The nanoparticle also exhibits high biostability and biocompatibility. To facilitate efficient urinary excretion of the nanoparticle, it may be coated with an organic polymer, such as poly(ethylene glycol) (PEG). The small size of the nanoparticle, the silica base and the organic polymer coating minimizes the toxicity of the nanoparticle when administered in vivo. In order to target a specific cell type, the nanoparticle may further be conjugated to a ligand, which is capable of binding to a cellular component associated with the specific cell type, such as a tumor marker. In one embodiment, a therapeutic agent may be attached to the nanoparticle. To permit the nanoparticle to be detectable by not only optical fluorescence imaging, but also other imaging techniques, such as positron emission tomography (PET), single photon emission computed tomography (SPECT), computerized tomography (CT), bioluminescence imaging, and magnetic resonance imaging (MM), radionuclides/radiometals or paramagnetic ions may be conjugated to the nanoparticle.

One or more aqueous, near infrared emitting, high yield, highly photoluminescent, stable quantum dots conjugated to one or more biomarkers specific moieties. The conjugated quantum dots have an enhanced detection sensitivity and selectivity and may be formed using a novel and efficient method for conjugating one or more biomarker specific moieties to the quantum dots. The invention is further directed to a method for using the conjugated quantum dots for cancer detection in the margin of excised tissue.

A novel near-IR emitting cationic silver chalcogenide quantum dot with a mixed coating wherein the coating comprises of at least 2 different types of materials and is capable of luminescence at the desired near IR bandwidth at wavelengths of 800-850 nm. The quantum dot is fabricated via an advantageous single-step, homogeneous, aqueous method at a low temperature resulting a near IR emitting semiconductor quantum dot with high Quantum Yield, high transfection with low toxicity. The quantum dots may be used in medical imaging, tumor detection, drug delivery and labeling as well as in quantum dot sensitized solar cells.

In this work we have targeted two aspects of GQDs, Size and ROS to reduce their cytotoxicity. Small size can damage cell organelles and production of ROS (reactive oxygen species) can hamper cell machinery in multiple ways. We have shown that cytotoxicity can be significantly reduced by embedding GQDs inside the PEG matrix rather than creating a thin shell around each GQD. Thin PEG shell around GQD can control ROS production but cannot circumvent the toxicity due to small size. Thus it was essential to solve both the issues. We have used a simple electrochemical method (12 h at room temperature) for synthesizing GQDs and embedded them in PEG matrix via a simple one step hydrothermal reaction (24 h at 160 C.) involving only GQDs, PEG, and deionized water. The P-GQDs formed after hydrothermal reaction show nanoparticles of diameter of 80-100 nm containing GQDs entrapped in PEG matrix. MTT assay showed significant 60% cells viability at a very high concentration of 5.5 mg/mL of P-GQDs compared to 10-15% viability for C-GQD and H-GQD. ROS production by P-GQDs was least compared to C-GQD and H-GQD in cell free and intracellular ROS assay suggesting involvement of ROS in cytotoxicity. In this work we have solved the issue of cytotoxicity due to small size and ROS generation without compromising with fluorescence properties of GQDs. P-GQDs was used for bioimaging and drug delivery in HeLa cells. In short we can obtain biocompatible P-GQDs in very short span of time with minimal use of hazardous chemicals and simple methodology.

The present invention provides a fluorescent silica-based nanoparticle that allows for precise detection, characterization, monitoring and treatment of a disease such as cancer The nanoparticle has a fluorescent compound positioned within the nanoparticle, and has greater brightness and fluorescent quantum yield than the free fluorescent compound To facilitate efficient urinary excretion of the nanoparticle, it may be coated with an organic polymer, such as polyethylene glycol) (PEG) The small size of the nanoparticle, the silica base and the organic polymer coating minimizes the toxicity of the nanoparticle when administered in vivo The nanoparticle may further be conjugated to a ligand capable of binding to a cellular component associated with the specific cell type, such as a tumor marker A therapeutic agent may be attached to the nanoparticle Radionuclides/radiometals or paramagnetic ions may be conjugated to the nanoparticle to permit the nanoparticle to be detectable by various imaging techniques.

Compositions of nanoparticles functionalized with at least one zwitterionic moiety, methods for making a plurality of nanoparticles, and methods of their use as diagnostic agents are provided. The nanoparticles have characteristics that result in minimal retention of the particles in the body compared to other nanoparticles. The nanoparticle comprising a nanoparticulate transition metal oxide covalently functionalized with a silane-functionalized non-targeting zwitterionic moiety.