A method of quantifying the concentration of a protein of interest, or the concentration of a conformational state of the protein of interest, in a mixture, wherein the protein of interest or conformational state has an intrinsic fluorescence decay signature. The method comprises: addressing the mixture with one or more pulses of light, wherein the light has a wavelength in the 240-295 nm range, preferably in the 250-280 nm range, further preferably wherein the laser light has a wavelength of 266 nm. The method further comprises: taking a series of measurements of the fluorescence intensity of the mixture at a series of time points where the time interval between a fluorescence measurement and a preceding light pulse is recorded. The series of measurements comprises measurements for which the time intervals differ from each other by less than a nanosecond, and where the difference between largest and smallest time intervals is at least 10 nanoseconds (ns) and/or a sufficient time to detect a decay of the fluorescence intensity towards a baseline level, such that the series of measurements defines a fluorescence decay curve. The method further comprises quantifying the concentration of a protein of interest or conformational state of the protein of interest in the sample by reference to the fluorescence decay curve.

The invention relates to a process and a device for analysing single molecules, particularly to the parallel analysis of a plurality of single molecules. It is suitable for detecting interactions, e.g. binding between single molecules and/or reactions, e.g. elongation or degradation of single molecules. Particularly, the process of the invention relates to the sequencing of single nucleic acid molecules. The single molecule to be analysed is present in free form, i.e. dissolved or suspended in a liquid medium, within a reaction space formed around the sample spot. According to the present invention, an electrical field is applied across the reaction space, whereby a concentration of single molecules, at the sample spots is effected.

Compact optical sources and methods for producing short and ultrashort optical pulses are described. A semiconductor laser or LED may be driven with a bipolar waveform to generate optical pulses with FWHM durations as short as approximately 85 ps having suppressed tail emission. The pulsed optical sources may be used for fluorescent lifetime analysis of biological samples and time-of-flight imaging, among other applications.

A method for detecting a reversibly photoswitchable chemical species in a sample, includes the steps of: a) illuminating the sample with light suitable to be absorbed by the chemical species triggering a reaction affecting an optical property of the chemical species, the first light being periodically-modulated at a fundamental modulation frequency; b) measuring the evolution of the optical property; c) extracting at least one of an in-phase component at a frequency which is an even multiple of the fundamental modulation frequency; and a quadrature component at a frequency which is an odd multiple of the fundamental modulation frequency of a signal representing the evolution; and d) using the extracted component or components for detecting the chemical species. An apparatus for carrying out the method is also provided.

A method of characterising a composition of a gemstone comprises irradiating an upper portion and a lower portion of the gemstone with one or more pulses of ultraviolet radiation at a wavelength of substantially 225 nm or less; capturing luminescence emitted by the upper portion of the gemstone and luminescence emitted by the lower portion of the gemstone in one or more time windows having a predetermined relationship with the or each pulse; and comparing properties of the captured luminescence from the upper and lower portions. A composition of the gemstone is characterised, based upon the comparison.

The disclosed embodiments relate to multimodal imaging system comprising a fiber-coupled fluorescence imaging system, which operates based on ultra-violet (UV) excitation light, and a fiber-coupled optical coherence tomography (OCT) imaging system. The multimodal imaging system also includes a fiber optic interface comprising a single optical fiber, which facilitates light delivery to a sample-of-interest and collection of returned optical signals for both the fluorescence imaging system and the OCT imaging system. During operation of the system, the single optical fiber carries both UV light and coherent infrared light through two concentric light-guiding regions, thereby facilitating generation of precisely co-registered optical data from the fluorescence imaging system and the OCT imaging system.

The invention provides systems for characterizing a biological sample by analyzing emission of fluorescent light from the biological sample upon excitation and methods for using the same. The system includes a laser source, collection fibers, a demultiplexer and an optical delay device. All references cited herein are incorporated by reference in their entirety as though fully set forth. Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of-ordinary skill in the art in which this invention belongs.

A reagent strip and a reagent analyzer for reading the reagent strip is described. The reagent strip includes a substrate, at least one reagent pad positioned on the substrate, and a photo luminescent phosphor spot positioned at a fixed location on the substrate. The photo luminescent phosphor spot is formulated to exhibit a predetermined addressable attribute.

The present invention provides for metallic structures comprising a sulfhydryl or amino-terminated hydrophilic coating to provide a layer of hydrophilic character on the surface of the metallic structures thereby allowing the use of low volumes of aqueous solvents of fluorophores that have the ability to “spread out” across the surfaces of the metallic structures and to provide for a more uniform surface coating of fluorophores attached to or near the metallic structures.

This invention provides methods and systems for measuring the concentration of multiple nucleic acid sequences in a sample. The nucleic acid sequences in the sample are simultaneously amplified, for example, using polymerase chain reaction (PCR) in the presence of an array of nucleic acid probes. The amount of amplicon corresponding to the multiple nucleic acid sequences can be measured in real-time during or after each cycle using a real-time microarray. The measured amount of amplicon produced can be used to determine the original amount of the nucleic acid sequences in the sample. Also provided herein are biosensor arrays, systems and methods for affinity based assays that are able to simultaneously obtain high quality measurements of the binding characteristics of multiple analytes, and that are able to determine the amounts of those analytes in solution. The invention also provides a fully integrated bioarray for detecting real-time characteristics of affinity based assays.