Effect of Protection Polymer Coatings on the Performance of an Amperometric Galactose Biosensor in Human Plasma.

Galactose monitoring in individuals allows the prevention of harsh health conditions related to hereditary metabolic diseases like galactosemia. Current methods of galactose detection need development to obtain cheaper, more reliable, and more specific sensors. Enzyme-containing amperometric sensors based on galactose oxidase activity are a promising approach, which can be enhanced by means of their inclusion in a redox polymer coating. This strategy simultaneously allows the immobilization of the biocatalyst to the electroactive surface and hosts the electron shuttling units. An additional deposition of capping polymers prevents external interferences like ascorbic or uric acid as well as biofouling when measuring in physiological fuels. This work studies the protection effect of poly(2-methacryloyloxyethyl phosphorylcholine-co-glycidyl methacrylate (MPC) and polyvinylimidazole-polysulfostyrene (P(VI-SS)) when incorporated in the biosensor design for the detection of galactose in human plasma.

Continuous ex vivo glucose sensing in human physiological fluids using an enzymatic sensor in a vein replica.

Managing blood glucose can affect important clinical outcomes during the intraoperative phase of surgery. However, currently available instruments for glucose monitoring during surgery are few and not optimized for the specific application. Here we report an attempt to exploit an enzymatic sensor in a vein replica that could continuously monitor glucose level in an authentic human bloodstream. First, detailed investigations of the superficial venous systems of volunteers were carried out using ocular and palpating examinations, as well as advanced ultrasound measurements. Second, a tubular glucose-sensitive biosensor mimicking a venous system was designed and tested. Almost ideal linear dependence of current output on glucose concentration in phosphate buffer saline was obtained in the range 2.2-22.0 mM, whereas the dependence in human plasma was less linear. Finally, the developed biosensor was investigated in whole blood under homeostatic conditions. A specific correlation was found between the current output and glucose concentration at the initial stage of the biodevice operation. However, with time, blood coagulation during measurements negatively affected the performance of the biodevice. When the experimental results were remodeled to predict the response without the influence of blood coagulation, the sensor output closely followed the blood glucose level.

Non-invasive Point-of-Care Device To Diagnose Acute Mesenteric Ischemia.

Inadequate blood supply to the intestine can lead to acute mesenteric ischemia (AMI), with a mortality rate ranging from 60% to 90%. This high mortality rate is partially due to late detection and the lack of efficient early diagnostic tests. There is an urgent need for a point-of-care tool for immediate bedside diagnosis. Here we present for the first time a rapid and non-invasive electrochemical biosensor device based on non-faradic impedance spectroscopy to detect intestinal fatty-acid binding protein (I-FABP) as an indication of AMI. The electrochemical biosensors consist of gold interdigitated electrodes that were fabricated using photolithographic techniques on top of silicon dioxide substrates. The electrode surfaces were functionalized with an I-FABP capture antibody (CAnB) to entice the target protein, while gold nanoparticles (GNPs) functionalized with detection antibodies (DAnB-GNPs) were utilized as a novel mechanism to enhance the detection signal. Quantification of the I-FABP concentration in the medium depended on its attachment to CAnB and DAnB-GNPs in a sandwich manner, where the latter boosts the impedance signal through its binding to the I-FABP. This non-invasive non-faradic electric biosensor device demonstrates the potential for bench-to-bedside translation with the goal of decreasing morbidity and mortality from AMI.