Elektrokemijski biosenzori za procjenu onečišćivača radi poboljšanja kakvoće hrane

This paper describes the application of electrochemical disposable biosensors in food analysis, which have recently been developed in our laboratory. The disposable biosensors, based on acetylcholinesterase inhibition potential, were exploited for testing the presence of organophosphorus and carbamatepesticides in water, fruit, and vegetable samples. The paper further describes preliminary tests for the detection of genetically modified organisms and hybridisation by coupling the DNA biosensors with the polymerase chain reaction.U radu su opisane neke primjene jednokratnih elektrokemijskih biosenzora za analizu hrane koji su nedavno razvijeni u našem laboratoriju. Biosenzori za jednokratnu upotrebu, bazirani na inhibiciji aktivnosti kolinesteraze primijenjeni su za ispitivanje prisutnosti organofosfornih i karbamatnih pesticida u uzorcima voda, voća i povrća. Razvijena je skupina DNK-biosenzora, a u ovom radu prikazani su rezultati preliminarnih ispitivanja detekcije genetički modificiranih organizama i hibridizacije vezanjem PCR i DNK-biosenzora

Electrochemical and PEC platforms for miRNA and other epigenetic markers of cancer diseases: Recent updates

Abstract Besides playing significant biological roles, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) constitute emerging and burgeoning cancer biomarkers collectable from human fluids. Electrochemical and photoelectrochemical biosensors offer great potential for their detection. However, the low abundance of such molecules in biological fluids, especially in early-stage cancer patients, makes it highly necessary to employ signal/sample amplification strategies. Among the variety of these strategies reported in the literature, in this review we summarize the recent advancements in the field, giving an account of the different approaches aimed to overcome this main obstacle. To this end, enzyme-, redox probe- and nanomaterial-based signal amplification strategies, as well as sample-amplification-hyphenated-techniques are assessed, by discussing selected examples. The highlighted approaches demonstrate the use of a variety of specific receptors and (photo)electrochemical assay formats, including the rapid development of novel biology-inspired sensing schemes

Amperometric separation-free immunosensor for real-time environmental monitoring

Immunoanalytical techniques have found widespread use due to the characteristics of specificity and wide applicability for many analytes, from large polymer antigens, to simple haptens, and even single atoms. Electrochemical sensors offer benefits of technical simplicity, speed and convenience via direct transduction to electronic equipment. Together, these two systems offer the possibility of a convenient, ubiquitous assay technique with high selectivity. However, they are still not widely used, mainly due to the complexity of the associated immunoassay methodologies. A separation-free immunoanalytical technique is described here, which has allowed for the analysis of atrazine in real time and in both quasi-equilibrium and stirred batch configurations. It illustrated that determinations as low as 0.13mM (28 ppb) could be made using equilibrium incubation with an analytical range of 0.1–10mM. Measurements could be made between 1 and 10 mM within several minutes using a real-time, stirred batch method. This system offers the potential for fast, simple, cost-effective biosensors for the analysis of many substances of environmental, biomedical and pharmaceutical concern

Tumor-derived microvesicles modulate antigen cross-processing via reactive oxygen species-mediated alkalinization of phagosomal compartment in dendritic cells

Dendritic cells (DCs) are the only antigen-presenting cells able to prime naïve T cells and cross-prime antigen-specific CD8+ T cells. Their functionality is a requirement for the induction and maintenance of long-lasting cancer immunity. Albeit intensively investigated, the in vivo mechanisms underlying efficient antigen cross-processing and presentation are not fully understood. Several pieces of evidence indicate that antigen transfer to DCs mediated by microvesicles (MVs) enhances antigen immunogenicity. This mechanism is also relevant for cross-presentation of those tumor-associated glycoproteins such as MUC1 that are blocked in HLA class II compartment when internalized by DCs as soluble molecules. Here, we present pieces of evidence that the internalization of tumor-derived MVs modulates antigen-processing machinery of DCs. Employing MVs derived from ovarian cancer ascites fluid and established tumor cell lines, we show that MV uptake modifies DC phagosomal microenvironment, triggering reactive oxygen species (ROS) accumulation and early alkalinization. Indeed, tumor MVs carry radical species and the MV uptake by DCs counteracts the chemically mediated acidification of the phagosomal compartment. Further pieces of evidence suggest that efficacious antigen cross-priming of the MUC1 antigen carried by the tumor MVs results from the early signaling induced by MV internalization and the function of the antigen-processing machinery of DCs. These results strongly support the hypothesis that tumor-derived MVs impact antigen immunogenicity by tuning the antigen-processing machinery of DCs, besides being carrier of tumor antigens. Furthermore, these findings have important implications for the exploitation of MVs as antigenic cell-free immunogen for DC-based therapeutic strategies

Nanostructured Photoelectrochemical Biosensing Platform for Cancer Biomarker Detection

The innovative photoelectrochemical properties of multifunctional nanomaterials are here investigated for the development of biosensing platforms for rapid and sensitive detection of a class of cancer biomarker candidates, known as microRNAs. Many different transducers have been proposed, so far, for microRNA detection. Recently, with the emergence of novel photoelectrochemically active species and new detection schemes, photoelectrochemistry has received increasing attention. Gold nanostructures have been, here, used to modify TiO2 electrodes. The surface of the nanostructured platform has been modified by nucleic acid capture probes (CPs). Biotinylated target miRNAs have been recognized by the specific CPs. The biosensing platform has been incubated with streptavidin alkaline phosphatase and exposed to a proper substrate. The product of the enzymatic reaction has been photoelectrochemically monitored. A compact and hand-held analytical device has been developed in order to have a final prototype in line with the concept of point of care testing. (C) 2017 The Authors. Published by Elsevier Ltd