arXiv subjects

Ivan Bobrinetskiy

Publications and source records attributed to Ivan Bobrinetskiy.

3 recordsLinked to original sources

arXiv2024

Direct electrochemical reduction of graphene oxide thin film for aptamer-based selective and highly sensitive detection of Matrix metalloproteinase 2

Simple and low-cost biosensing solutions are suitable for point-of-care applications aiming to overcome the gap between scientific concepts and technological production. To compete with sensitivity and selectivity of golden standards, such as liquid chromatography, the functionalization of biosensors is continuously optimized to enhance the signal and improve their performance, often leading to complex chemical assay development. In this research, the efforts are made on optimizing the methodology for electrochemical reduction of graphene oxide to produce thin film-modified gold electrodes. Under the employed specific conditions, 20 cycles of cyclic voltammetry (CV) are shown to be optimal for superior electrical activation of graphene oxide into electrochemically reduced graphene oxide (ERGO). This platform is further used to develop a matrix metalloproteinase 2 (MMP-2) biosensor, where specific anti-MMP2 aptamers are utilized as a biorecognition element. MMP-2 is a protein which is typically overexpressed in tumor tissues, with important roles in tumor invasion, metastasis as well as in tumor angiogenesis. Based on impedimetric measurements, we were able to detect as low as 3.32 pg/mL of MMP-2 in PBS with a dynamic range of 10 pg/mL - 10 ng/mL. Besides high specificity, ERGO-based aptasensor showed a potential of reuse due to demonstrated successful signal restoration after experimental detection of MMP-2.

physics.app-ph↗

arXiv2023

Femtomolar detection of the heart failure biomarker NT-proBNP in artificial saliva using an immersible liquid-gated aptasensor with reduced graphene oxide

Measuring NT-proBNP biomarker is recommended for preliminary diagnostics of the heart failure. Recent studies suggest a possibility of early screening of biomarkers in saliva for non-invasive identification of cardiac diseases at the point-of-care. However, NT-proBNP concentrations in saliva can be thousand time lower than in blood plasma, going down to pg/mL level. To reach this level, we developed a label-free aptasensor based on a liquid-gated field effect transistor using a film of reduced graphene oxide monolayer (rGO-FET) with immobilized NT-proBNP specific aptamer. We found that, depending on ionic strength of tested solutions, there were different levels of correlation in responses of electrical parameters of the rGO-FET aptasensor, namely, the Dirac point shift and transconductance change. The correlation in response to NT-proBNP was high for 1.6 mM phosphate-buffered saline (PBS) and zero for 16 mM PBS in a wide range of analyte concentrations, varied from 1 fg/mL to 10 ng/mL. The effects of transconductance and Dirac point shift in PBS solutions of different concentrations are discussed. The biosensor exhibited a high sensitivity for both transconductance (2 uS/decade) and Dirac point shift (2.3 mV/decade) in diluted PBS with the linear range from 10 fg/mL to 1 pg/mL. The aptasensor performance has been also demonstrated in undiluted artificial saliva with the achieved limit of detection down to 41 fg/mL (~4.6 fM).

cond-mat.mtrl-sci↗

arXiv2021

Real-time detection of Ochratoxin A in wine through insight of aptamer conformation in conjunction with graphene field-effect transistor

Mycotoxins comprise a frequent type of toxins present in food and feed. The problem of mycotoxin contamination has been recently aggravated due to the increased complexity of the farm-to-fork chains, resulting in negative effects on human and animal health and, consequently, economics. The easy-to-use, on-site, on-demand, and rapid monitoring of mycotoxins in food/feed is highly desired. In this work, we report on an advanced mycotoxin biosensor based on an array of graphene field-effect transistors integrated on a single silicon chip. A specifically designed aptamer against Ochratoxin A (OTA) was used as a recognition element, where it was covalently attached to graphene surface via pyrenebutanoic acid, succinimidyl ester (PBASE) chemistry. Namely, an electric field stimulation was used to promote more efficient π-π stacking of PBASE to graphene. The specific G-rich aptamer strand suggest its π-π stacking on graphene in free-standing regime and reconfiguration in G-quadruplex during binding an OTA molecule. This realistic behavior of the aptamer is sensitive to the ionic strength of the analyte solution, demonstrating a 10-fold increase in sensitivity at low ionic strengths. The graphene-aptamer sensors reported here demonstrate fast assay with the lowest detection limit of 1.4 pM for OTA within a response time as low as 10 s, which is more than 30 times faster compared to any other reported aptamer-based methods for mycotoxin detection. The sensors hold comparable performance when operated in real-time within a complex matrix of wine without additional time-consuming pre-treatment.

cond-mat.mtrl-sci↗