Biology subjects

Vidic, J.

Publications and source records attributed to Vidic, J..

3 recordsLinked to original sources

bioRxiv2023

Electrochemical biosensor based on NAD(P)H-dependent Quinone Reductase for rapid and efficient detection of vitamin K3

Vitamin K refers to a group of vitamins that play an important role in blood coagulation and regulation of bone and vascular metabolism. However, vitamin K3 may give severe side effects in animal and humans when improperly added to food and feed due to its toxicity. Here, an electrochemical biosensor, based on the YaiB NADPH-dependent quinone reductase from Lactococcus lactis (YaiB), was developed to achieve rapid and redox probe-free detection of vitamin K3. First, we demonstrated the ability of the carbon electrode to distinguish between 1,4-benzoquinone and hydroquinone. Then, we engineered YaiB to work as a bioreceptor immobilized at the electrode and we demonstrated its sensitivity and specificity to reduce vitamin K3. Finally, to demonstrate the practical potential of the biosensor, we tested it directly in spiked milk samples, achieving 15-minute quantification of the vitamin K3. The limit of detection was 0.18M and 0.86 M in buffer and milk, respectively.

biophysics↗

bioRxiv2022

Low-cost gold-leaf electrode as a platform for Escherichia coli immuno-detection

Gold electrodes are one of most prevalent substrates in electrochemical biosensors because they can be easily and highly efficiently functionalized with thiolated biomolecules. However, conventional methods to fabricate gold electrodes are costly, time consuming and require onerous equipment. Here, an affordable method for rapid fabrication of an electrochemical immune-sensor for Escherichia coli detection is presented. The gold electrode was generated using 24-karat gold leaves and low-cost polyvinyl chloride adhesive sheets covered with an insulating PTFE layer. The gold-leaf electrode (GLE) was patterned using laser ablation and characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electronic microscopy, contact angle and 3D profiling. The GLEs were modified by a self-assembled mercaptopropionic monolayer, followed by surface activation to allow binding of the specific anti-E. coli antibody via carbodiimide linking. The biosensor showed a detection limit of 2 CFU/ml and a linear dynamic range of 10 - 107 CFU/ml for E. coli cells. No false positive signals were obtained from control bacteria. The obtained results demonstrated suitability of GLE for use in biosensors with high reliability and reproducibility. It is foreseeable that our work will inspire design of point-of-need biosensors broadly applicable in low-resource settings.

microbiology↗

bioRxiv2020

A Highly Sensitive Detection of Campylobacter spp. in Chicken Meat using Silica Nanoparticle Enhanced Dot Blot DNA Biosensor

Paper-based DNA biosensors are powerful tools in point-of-care diagnostics since they are affordable, portable, user-friendly, rapid and robust. However, their sensitivity is not always as high as required to enable DNA quantification. To improve the response of standard dot blots, we have applied a new enhancement strategy that increases the sensitivity of assays based on the use of biotinylated silica-nanoparticles (biotin-Si-NPs). After immobilization of a genomic Campylobacter DNA onto a paper membrane, and addition of a biotinylated-DNA detection probe, hybridization was evidenced using streptavidin-conjugated to horseradish peroxidase (HRP) in the presence of luminol and H2O2. Replacement of the single biotin by the biotin-Si-NPs boosted on average a 30 fold chemiluminescent read-out of the biosensor. Characterization of biotin-Si-NPs onto a paper with immobilized DNA was done using a scanning electron microscope. A limit of detection of 3 pg/L of DNA, similar to the available qPCR kits, is achieved, but it is cheaper, easier and avoids inhibition of DNA polymerase by molecules from the food matrices. We demonstrated that the new dot blot coupled to biotin-Si-NPs successfully detected Campylobacter from naturally contaminated chicken meat, without needing a PCR step. Hence, such an enhanced dot blot paves the path to the development of a portable and multiplex paper based platform for point-of-care screening of chicken carcasses for Campylobacter. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=54 SRC="FIGDIR/small/185827v2_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@14eca5org.highwire.dtl.DTLVardef@1bc582borg.highwire.dtl.DTLVardef@40836eorg.highwire.dtl.DTLVardef@174caaf_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗