The present invention relates to a method for production of an improved sensor surface for an SPR instrument, comprising forming a self assembled monolayer (SAM) on a surface and attaching ligands and protein resistant groups, preferably polyethylene glycol (PEG), directly to functional groups on said surface. The invention also relates to a sensor surface produced by these methods use thereof in SPR (surface plasmon resonance) assays or interactions.

The present disclosure provides methods, systems, and kits for detecting molecules in a sample with a pre-equilibrium digital immunoassay. The methods and systems provide means for quantifying molecules in a biological sample of minimal volume in short amounts of time.

The present disclosure provides methods, systems, and kits for detecting molecules in a sample with a pre-equilibrium digital immunoassay. The methods and systems provide means for quantifying molecules in a biological sample of minimal volume in short amounts of time.

The presently-disclosed subject matter relates to crosslinkers, compositions, and methods for trapping a target of interest on a substrate of interest. The methods may be used to inhibit and treat pathogen infection and provide contraception. The methods may be used to trap or separate particles and other substances. The subject matter further relates to methods of identifying and preparing optimal crosslinkers and methods for manipulating targets of interest.

The presently-disclosed subject matter relates to crosslinkers, compositions, and methods for trapping a target of interest on a substrate of interest. The methods may be used to inhibit and treat pathogen infection and provide contraception. The methods may be used to trap or separate particles and other substances. The subject matter further relates to methods of identifying and preparing optimal crosslinkers and methods for manipulating targets of interest.

A method and system for determining the dissociation constant (K.sub.d) of a reversible binding pair of a first compound and a second compound. The method comprises: injecting a sample into a capillary tube via one or more valves, wherein the sample comprises the first compound, the second compound, and a first compound-second compound complex; injecting a mobile phase into the capillary tube via said one or more valves, the sample flowing through the capillary tube under laminar flow conditions, wherein the second compound and the first compound-second compound complex is separated from the first compound by transverse diffusion; measuring time dependence of a signal that is proportional to the concentration of the first compound, both unbound and bound to the second compound using a measurement component; and determining the equilibrium dissociation constant based on the measured signal versus time dependence.

A method and system for determining the dissociation constant (K.sub.d) of a reversible binding pair of a first compound and a second compound. The method comprises: injecting a sample into a capillary tube via one or more valves, wherein the sample comprises the first compound, the second compound, and a first compound-second compound complex; injecting a mobile phase into the capillary tube via said one or more valves, the sample flowing through the capillary tube under laminar flow conditions, wherein the second compound and the first compound-second compound complex is separated from the first compound by transverse diffusion; measuring time dependence of a signal that is proportional to the concentration of the first compound, both unbound and bound to the second compound using a measurement component; and determining the equilibrium dissociation constant based on the measured signal versus time dependence.

A system and method for electrical label-free detection of single protein molecules via a nanoscale electrode based on detecting the transient potential change of the floating nanoelectrode, which works for both large and small molecules. The system can also be applied to study the interactions of molecules with molecular receptors on the surface of the nanoscale electrode. The motion and dynamics of the protein near the nanoscale electrode can be detected with high precision in real time based on their intrinsic charges by the potentiometric method using a differential amplifier. The nanoelectrode can be integrated into a microfluidic device for biosensing applications.

A system and method for electrical label-free detection of single protein molecules via a nanoscale electrode based on detecting the transient potential change of the floating nanoelectrode, which works for both large and small molecules. The system can also be applied to study the interactions of molecules with molecular receptors on the surface of the nanoscale electrode. The motion and dynamics of the protein near the nanoscale electrode can be detected with high precision in real time based on their intrinsic charges by the potentiometric method using a differential amplifier. The nanoelectrode can be integrated into a microfluidic device for biosensing applications.

An apparatus for label-free analysis of molecules, including interactions and reactions of the molecules, is disclosed. The apparatus is based on detecting molecule movement under the influence of an external electric field. The apparatus is able to achieve sensitive detection of molecular binding to proteins or other molecules, and conformational changes of proteins or other molecules and biochemical reactions of the proteins or other molecules. Applications of the apparatus include screening of drug molecules, kinetic analysis of posttranslational modification of proteins, and small molecule-protein interactions.