A biosensing system includes a biosensor, a light source, first and second photodetectors, and a calculator. The light source is disposed to irradiate the biosensor, so as to generate two or more of a coupled light beam, a reflected light beam, a transmitted light beam and a diffracted light beam. The first photodetector is disposed to measure an intensity of one of the generated light beams that is indicative of an effect of an analyte on light to obtain a first intensity value. The second photodetector is disposed to measure an intensity of another one of the generated light beams that is indicative of an effect of the analyte on light to obtain a second intensity value. The calculator performs compensation calculation based at least on the first and second intensity values.

Disclosed are a selective colorimetric detection sensor and a colorimetric detection method for C.sup.6+ ions using size controlled label-free gold nanoparticles, which may be useful for the detection of toxic materials such as heavy metal ions in the environmental sector and the industry. Selective colorimetric sensor solution used therein is selectively reacted with only Cr.sup.6+ ions in trivalent chromium ions (Cr.sup.3+) and hexavalent chromium ions (Cr.sup.6+), and there is no interference effect resulting from other metal ions, and it is possible to very rapidly and precisely detect Cr.sup.6+ ions compared to the related art.

The determination of hydroxyl radical scavenging capacity of contaminated water can be achieved by developing an external calibration model. The model can be prepared using standard solutions where scavenging capacities are determined, and then the solutions are treated with addition of an oxidant and a dye, followed by UV treatment to form hydroxyl radicals that are scavenged by species in the standard solution. The residual dye content can then be measured using absorbance. The absorbance and the scavenging capacity data for the standard solutions are used to build the model, which can then be implemented to determine scavenging capacity of contaminated water. Water samples can be subjected to the same treatment as the standard solutions, the absorbance of the water sample is then obtained, and then the model is used to determine the corresponding scavenging capacity. Determining scavenger capacity of contaminated water can aid in advanced oxidation processing (AOP).

The present application relates sensing reactive components in fluids by monitoring band gap changes to a material having interacted with the reactive components via physisorption and/or chemisorption. In some embodiments, the sensors of the present disclosure include the material as a reactive surface on a substrate. The band gap changes may be detected by measuring conductance changes and/or spectroscopic changes. In some instances, the sensing may occur downhole during one or more wellbore operations like drilling, hydraulic fracturing, and producing hydrocarbons.

Embodiments described herein may be useful in the detection of analytes. The systems and methods may allow for a relatively simple and rapid way for detecting analytes such as chemical and/or biological analytes and may be useful in numerous applications including sensing, food manufacturing, medical diagnostics, performance materials, dynamic lenses, water monitoring, environmental monitoring, detection of proteins, detection of DNA, among other applications. For example, the systems and methods described herein may be used for determining the presence of a contaminant such as bacteria (e.g., detecting pathogenic bacteria in food and water samples which helps to prevent widespread infection, illness, and even death). Advantageously, the systems and methods described herein may not have the drawbacks in current detection technologies including, for example, relatively high costs, long enrichment steps and analysis times, and/or the need for extensive user training. Another advantageous feature provided by the systems and methods described herein includes fabrication in a relatively large scale. In some embodiments, the systems and methods may be used in conjunction with a detector including handheld detectors incorporated with, for example, smartphones (e.g., for the on-site detection of analytes such as pathogenic bacteria).

A biosensor, and a preparation and biosensing method therefor. The biosensor includes: a sensing substrate, wherein a plurality of sensing suspending arms arranged in an array are arranged on the sensing substrate, and the sensing suspending arms have identification markers; and a detection substrate, the detection substrate including a plurality of light detection assemblies arranged in an array, wherein the light detection assemblies and the sensing suspending arms are arranged in one-to-one correspondence, each of the light detection assemblies includes a photodiode and a thin film transistor, and the photodiode is connected to the thin film transistor.

A transmittance based system/kit for point-of-care quantification of biomarker samples includes a stage supporting a detection unit, an optical transmittance unit and a signal processing unit. The detection unit comprising reactive substrate is capable of undergoing a specific biomarker sample interactive reaction and generating a quantifiable optical signal proportional to the concentration of the said biomarker sample wherein the intensity of the color varies with the concentration of the analyte in the bio-sample. The optical transmittance unit, comprises a sample stage integrated with the light source and a photodetector, converting quantifiable optical signal transmitted through the reagent coated substrate detection unit to electrical signals, a signal processing unit connected to the said optical transmittance unit transduces the analogue electrical signal into the digital display signal. The simple, single step, cost-effective easily disposable system/kit is useful for point-of-care detection of important biomarkers such as amylase, creatinine, albumin, among others.

The invention relates to sensor cards for determining and/or monitoring solute concentration and/or pH of a fluid based on an optically observable change of a sensing membrane or colorimetric material in the presence of ions in solution. The sensor cards can be placed in a fluid sensor apparatus and used to determine the solute concentration and/or pH of any fluid, such as dialysate.

The invention provides an in vitro method for the determination of sun protection factor (SPF), in order to gain reproducibility and accuracy and replace the use of tests on living beings. Natural substrates of the human skin, like hyaluronic acid are tested in the form of solutions or in the form of a solid film in a modified spectrophotometer, at concentrations below 1% w/v. Once calibrated, the method is used to corroborate the protection factor offered by commercial sunscreens.

A microfluidic device for evaluation of an organic/inorganic scale inhibitor is provided. The device comprises a substrate mountable to a disc for rotation about an axis. The device further comprises a proximal end and a distal end. The substrate defines a sample reservoir, a solvent reservoir, an inhibitor reservoir, and a precipitant reservoir at the proximal end and an analysis chamber at the distal end in fluid communication with the sample, solvent, inhibitor, and precipitant reservoirs. The substrate is constructed to direct one or more of fluids in the sample reservoir, solvent reservoir, inhibitor reservoir, and precipitant reservoir radially outwardly towards the analysis chamber under the influence of centrifugal force when the microfluidic device rotates.