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In this work, we evaluate for the first time the performance of a label-free porous silicon (PSi) immunosensor assay in a blind clinical study designed to screen authentic patient urine specimens for a broad range of opiates. The PSi opiate immunosensor achieved 96% concordance with liquid chromatography-mass spectrometry/tandem mass spectrometry (LC-MS/MS) results on samples that underwent standard opiate testing (n = 50). In addition, successful detection of a commonly abused opiate, oxycodone, resulted in 100% qualitative agreement between the PSi opiate sensor and LC-MS/MS. In contrast, a commercial broad opiate immunoasssy technique (CEDIA) achieved 65% qualitative concordance with LCMS/MS. Evaluation of important performance attributes including precision, accuracy, and recovery was completed on blank urine specimens spiked with test analytes. Variability of morphine detection as a model opiate target was 10.1021/ac101804s

A low-cost photonic lab on a chip with three different working regimes for cell screening is presented. The proposed system is able to perform scattering, scattering + absorption, and absorption measurements without any modification. Opposite to the standard flow cytometers, in this proposed configuration, a single 30 ms scan allows to obtain information regarding the cell optical properties. An additional novelty is that the whole spectrum is obtained and analyzed, being then possible to determine for each regime which is the optimal working wavelength that would provide the best performance in terms of sensitivity and limit of detection (LOD). Experimental results have provided with an LOD of 54.9 [+ or -] 0.7 cells (in the scattering regime using unlabeled cells), 53 [+ or -] 1 cells (in the scattering + absorption regime using labeled cells), and 105 [+ or -] 4 cells (in the absorption regime using labeled cells). Finally, the system has also been used for measuring the dead/live cell ratio, obtaining LODs between 7.6 [+ or -] 0.4% and 6.7 [+ or -] 0.3%, depending on the working regime used. 10.1021/ac100590z