Abstract: Lipase activity can be detected with a biosensor that includes a quantum dot adhered to a construct having a lipase-cleavable ester to attach a fluorophore acceptor configured as a Förster resonance energy transfer (FRET) acceptor to the QD when the construct is bound thereto. Cleavage of the ester by a lipase results in a measurable reduction in FRET. In further embodiments, the cleavable ester can be used to detect esterase activity, or the ester could be replaced with a glycosidic linkage to detect glycoside activity.

Abstract: Lipase activity can be detected with a biosensor that includes a quantum dot adhered to a construct having a lipase-cleavable ester to attach a fluorophore acceptor configured as a Förster resonance energy transfer (FRET) acceptor to the QD when the construct is bound thereto. Cleavage of the ester by a lipase results in a measurable reduction in FRET. In further embodiments, the cleavable ester can be used to detect esterase activity, or the ester could be replaced with a glycosidic linkage to detect glycoside activity.

Abstract: Provided are compositions and methods for promoting tolerance to auto-immune antigens. In general the compositions include quantum dots (QDs) that are in association with auto-immune peptide antigens. It is shown that QDs can be used to generate immunological tolerance by controlling the density of self-antigen on QDs. Peptide-QDs rapidly concentrate in draining lymph nodes, and co-localize with macrophages expressing scavenger receptors involved intolerance. Treatment with peptide-QDs reduces disease incidence 10-fold. The degree of tolerance and the underlying expansion of regulatory T cells correlates with the density of myelin molecules presented on QDs such that higher numbers of tolerogenic particles displaying lower levels of self-peptide are more effective for inducing tolerance than fewer particles each displaying higher densities of peptide. The disclosure is therefore relevant to promoting tolerance to antigens that are involved in a variety of autoimmune disorders.

Abstract: Provided are compositions and methods for promoting tolerance to auto-immune antigens. In general the compositions include quantum dots (QDs) that are in association with auto-immune peptide antigens. It is shown that QDs can be used to generate immunological tolerance by controlling the density of self-antigen on QDs. Peptide-QDs rapidly concentrate in draining lymph nodes, and co-localize with macrophages expressing scavenger receptors involved intolerance. Treatment with peptide-QDs reduces disease incidence 10-fold. The degree of tolerance and the underlying expansion of regulatory T cells correlates with the density of myelin molecules presented on QDs such that higher numbers of tolerogenic particles displaying lower levels of self-peptide are more effective for inducing tolerance than fewer particles each displaying higher densities of peptide. The disclosure is therefore relevant to promoting tolerance to antigens that are involved in a variety of autoimmune disorders.

Abstract: A method of controllably changing an intrinsic property of a quantum dot by using a biological entity, either attached or in close proximity to the quantum dot, and changing the state of biological entity with a controllable mechanism. The change in state of the biological entity controllably changes the intrinsic property of the quantum dot. The photoluminescence emission of quantum dots can be controlled by the present method. The methods disclosed include controlling the magnitude of QD photoluminescence as well as turning the photoluminescence on/off. The methods disclosed include using the same biological control architecture to control other intrinsic QD properties such as charge state, magnetic or other property.

Abstract: This invention pertains to a surface ligand; preparation of the ligand; colloidal nanoparticle, such as quantum dot bearing one or more of the ligand; and a bioconjugate characterized by a nanoparticle bearing one or more of the ligand conjugated to a biomolecule. The ligand is characterized by the presence of a first module containing atoms that can attach to an inorganic surface; a second module that imparts water-solubility to the ligand and to the inorganic surface that may be attached to the ligand; and a third module that contains a functional group that can, directly or indirectly, conjugate to a biomolecule. Order of the modules can be different and other modules and groups can be on the ligand. Preparation of the ligand includes the steps of reacting a compound having atoms that can attach to an inorganic surface with a water-solubilizing compound that imparts the property of water-solubility to the ligand and the inorganic surface to which it may be attached and purification thereof.

Abstract: This invention pertains to a surface ligand; preparation of the ligand; colloidal nanoparticle, such as quantum dot bearing one or more of the ligand; and a bioconjugate characterized by a nanoparticle bearing one or more of the ligand conjugated to a biomolecule. The ligand is characterized by the presence of a first module containing atoms that can attach to an inorganic surface; a second module that imparts water-solubility to the ligand and to the inorganic surface that may be attached to the ligand; and a third module that contains a functional group that can, directly or indirectly, conjugate to a biomolecule. Order of the modules can be different and other modules and groups can be on the ligand. Preparation of the ligand includes the steps of reacting a compound having atoms that can attach to an inorganic surface with a water-solubilizing compound that imparts the property of water-solubility to the ligand and the inorganic surface to which it may be attached and purification thereof.