Computer screen illumination for the characterization of colorimetric assays

Computer screen photo-assisted detection of complementary DNA strands using a luminescent zwitterionic polythiophene derivative

“…1b). After the filters, the light excites the detector (of spectral response D(λ)) and is integrated along the complete range of visible wavelengths, providing an intensity value from each channel of the web camera [1,12]. To highlight the features of the samples the intensity collected from a reference substance (distilled water in this case) is subtracted, producing the sensing signal I, which e.g.…”

LCD-aided computer screen photo-assisted technique for colorimetric assays evaluation

“…The CSPT concept has been demonstrated so far using CRT screens, for diverse applications as hormone detection [4], cell viability assays for drug testing [3] and color recognition [1,7] using printed samples or staining substances in microtiterplate format. Obviously, computer screens are not the best light source in nominal terms but considering the benefits they offer regarding home applications, the trade off is fair and motivate us to overcome the related difficulties.…”

“…Indeed, one possible alternative is to measure the complete array without samples to formulate a map of individual references, which has been used in fixed format arrays [3,4,7] (e.g. 96 wells microtiterplates), but this demands a complementary measurement which is preferable to avoid.…”

“…A MatLab program decomposes the video file in individual frames extracting the information of light intensity (evaluated as gray levels [3,7,8]) in all the pixels composing the image of each sample spot and calculates the average value (I j i ) and standard deviation (evaluated over 314 pixels, per sample spot j). Repeating the procedure for all Composed intensity from the red, green and blue channels of the web camera for the reference spot (sample 6 in (a)), evaluated along the color sequence.…”

Compact System for Colorimetric Sensor Arrays Characterization Based on Computer Screen Photo-Assisted Technology

“…The Computer Screen Photo-assisted Technique is a characterization technique that is based on a simple but effective idea: it exploits the possibility of using parts of a computer screen as a programmable light source and a camera to record and analyze changes in the spectrum produced by the sample [25,26,[31][32][33][34][35][36]. This technique aims to create a device capable of analyzing the presence of certain gases in the air by using mainly commercially available devices.…”