Abstract: Provided herein is a method for biosensing a target substance [110] using a collection of particles [104] tethered to a surface [100] by tether molecules [102] and a plurality of capture molecules. A concentration of the target substance is determined from the time sequence of individual association/dissociation rates of the capture molecules. Competitive assay configurations are also described.

Abstract: A method for sensing an analyte uses tethered particle motion. A functionalized particle has a first state in which the functionalized particle is bound to the surface and a second state in which the functionalized particle is not bound to the surface, where the functionalized particle switches between the first and second states depending on the presence and absence of the analyte, thereby changing motion characteristics of the functionalized particle depending on the presence of the analyte. A spatial coordinate parameter of the functionalized particle is measured by a detector, and a processor determines the presence/concentration of the analyte from changes in the measured spatial coordinate parameter.

Abstract: A method for sensing an analyte uses tethered particle motion. A functionalized particle has a first state in which the functionalized particle is bound to the surface and a second state in which the functionalized particle is not bound to the surface, where the functionalized particle switches between the first and second states depending on the presence and absence of the analyte, thereby changing motion characteristics of the functionalized particle depending on the presence of the analyte. A spatial coordinate parameter of the functionalized particle is measured by a detector, and a processor determines the presence/concentration of the analyte from changes in the measured spatial coordinate parameter.

Abstract: A method for biosensing a target substance [110] uses a collection of particles [?] tethered to a surface [100] by tether molecules [102]. First capture molecules [106] are attached to the particles [104] or to the tether molecules. Second capture molecules [108] are attached to the surface [100] or to the tether molecules. The first capture molecules [106] are selected to bind to the target substance [110] and have a first target dissociation rate, and the second capture molecules [108] are selected to bind to the target substance [110] and have a second target dissociation rate that differs from the first target dissociation rate by at least a factor of three. A time series of a spatial coordinate parameter of the particles is detected, and identifying a time sequence of individual association/dissociation events of the target substance with the capture molecules are identified within the detected time series.

Abstract: A method for sensing an analyte uses tethered particle motion. A functionalized particle [500] has a first state [504] in which the functionalized particle is bound to the surface and a second state [502] in which the functionalized particle is not bound to the surface, where the functionalized particle switches between the first and second states depending on the presence and absence of the analyte, thereby changing motion characteristics of the functionalized particle depending on the presence of the analyte. A spatial coordinate parameter of the functionalized particle is measured by a detector [516], and a processor [518] determines the presence/concentration of the analyte from changes in the measured spatial coordinate parameter.

Abstract: A method for sensing an analyte uses tethered particle motion. A functionalized particle [500] has a first state [504] in which the functionalized particle is bound to the surface and a second state [502] in which the functionalized particle is not bound to the surface, where the functionalized particle switches between the first and second states depending on the presence and absence of the analyte, thereby changing motion characteristics of the functionalized particle depending on the presence of the analyte. A spatial coordinate parameter of the functionalized particle is measured by a detector [516], and a processor [518] determines the presence/concentration of the analyte from changes in the measured spatial coordinate parameter.

Abstract: An immersion lithographic apparatus includes a surface having at least one active group (e.g., lyophobic group) which, during use, comes into contact with immersion liquid, and an immersion liquid supply system configured to provide immersion liquid comprising a protection component which is more reactive with a product of photoionization of the immersion liquid than the active group of the surface, the protection component being present in an amount of between 1 ppm and 0.1 ppm.