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A low-cost strategy for the simple and rapid detection of bacterial cells in biological matrixes is presented herein. Escherichia coli and Salmonella typhimurium were chosen as model bacteria for the development of an electrochemical assay based on hollow AuAg nanoshells (NSs). By taking advantage of their electrocatalytic properties for the in situ generation of the electrochemical signal without the need of any other kind of reagent, substrate, or redox enzyme, high sensitivities (down to 10 2 CFU/mL) were achieved. Moreover, the recognition and discrimination of the model bacterial cells in the sample matrix was possible by relying solely on nonspecific affinity interactions between their cell walls and AuAg NSs surface, avoiding the use of expensive and fragile biological receptor. Compared to traditional, laboratorybased analytical tests available, this assay provides a promising proof-of-concept alternative that allows to obtain good sensitivities and selectivity in very short times in addition to the low cost.

Our results evidence a high frequency of the -44 CC allele in HIV-1 infected mothers and their children with augmented potential risk of maternal fetal transmission. This potential vertical transmission risk has been successfully prevented by antiretroviral drug treatment and cesarian section of the HIV-1 positive mothers.

The first competitive disposable amperometric immunosensor based on gliadin-functionalized carbon/nanogold screen-printed electrodes was developed for rapid determination of celiotoxic prolamins. To date, no competitive spectrophotometric or electrochemical immunoassays have yet been successfully applied to gluten detection in processed food samples, which require the use of complex prolamin extraction solutions containing additives with denaturing, reducing and disaggregating functions. Thus, in this work, great effort was put into the optimization and performance evaluation of the immunosensor in terms of suitability as a screening tool for analysis of cereal-based food samples. For this purpose, aqueous ethanol or complex extraction mixtures, as the patented Cocktail Solution®, were proved effective in the extraction of gliadin. Good sensitivity was achieved after optimization of the immunocompetitive assay, giving limit of detection and limit of quantitation of 8 and 22 ng/ml of gliadin, respectively, for ethanol extracts. The immunosensor was proved to be suitable also for samples extracted with Cocktail Solution® after a proper dilution. Analysis of real samples of different flours proved the suitability of the immunosensing device as a powerful tool for safety assessment of raw materials used for the formulation of dietary products for celiac disease patients. This immunosensor combines good analytical performance using a very simplified set-up protocol with suitability for rapid screening analysis performed using inexpensive and portable instrumentation. Graphical abstract Depiction of the development and working principle of the competitive immunosensor.