Non-invasive, ultrasensitive detection of glucose in saliva using metal oxide transistors

High-performance electrolyte-gated amorphous InGaZnO field-effect transistor for label-free DNA sensing

Accurate, convenient, label-free, and cost-effective biomolecules detection platforms are currently in high demand. In this study, we showcased the utilization of electrolyte-gated InGaZnO field-effect transistors (IGZO FETs) featuring a large on-off current ratio of over 106 and a low subthreshold slope of 78.5 mV/dec. In the DNA biosensor, the modification of target DNA changed the effective gate voltage of IGZO FETs, enabling an impressive low detection limit of 0.1 pM and a wide linear detection range from 0.1 pM to 1 μM. This label-free detection method also exhibits high selectivity, allowing for the discrimination of single-base mismatch. Furthermore, the reuse of gate electrodes and channel films offers cost-saving benefits and simplifies device fabrication processes. The electrolyte-gated IGZO FET biosensor presented in this study shows great promise for achieving low-cost and highly sensitive detection of various biomolecules.

Recent advances in biosensors based on metal-oxide semiconductors system-integrated into bioelectronics

Metal-oxide semiconductors (MOSs) have emerged as pivotal components in technology related to biosensors and bioelectronics. Detecting biomarkers in sweat provides a glimpse into an individual's metabolism without the need for sample preparation or collection steps. The distinctive attributes of this biosensing technology position it as an appealing option for biomedical applications beyond the scope of diagnosis and healthcare monitoring. This review encapsulates ongoing developments of cutting-edge biosensors based on MOSs. Recent advances in MOS-based biosensors for human sweat analyses are reviewed. Also discussed is the progress in sweat-based biosensing technologies to detect and monitor diseases. Next, system integration of biosensors is demonstrated ultimately to ensure the accurate and reliable detection and analysis of target biomarkers beyond individual devices. Finally, the challenges and opportunities related to advanced biosensors and bioelectronics for biomedical applications are discussed.

Greek School Nurses' Confidence With Diabetes Devices

Aim School nurses often use diabetes mellitus devices as part of the care provided to students with Type 1 Diabetes Mellitus. The aim of this study was to explore the psychometric properties of the Greek version of the Diabetes Devices Confidence Scale (DDCS). Methods In this cross-sectional, descriptive study, 143 school nurses completed the DDCS. This is a self-administered questionnaire exploring the nurses' confidence in the use of diabetes devices. The scale was translated and culturally adapted according to the WHO guidelines. The Intraclass Correlation Coefficient and Cronbach's Alpha Index were used to explore the reliability and internal consistency, respectively. The construct validity was tested via exploratory and confirmatory factor analysis (EFA, CFA). Data were analyzed via Statistical Package for the Social Sciences (SPSS), version 22.0 (IBM Corp., Armonk, NY, USA). Results Significant correlations were observed between the two administrations (p<0.001) indicating the good reliability of the scale (ICC = 0525, p<0.001) while Cronbach's Alpha was 0.966 suggesting excellent internal consistency. The EFA resulted in a unidimensional solution explaining 53.7% of the total variance. The CFA showed that the model presents good fit to the data. Conclusions The DDCS is a reliable and valid tool to test the nurses' confidence in diabetes devices.

Label-Free Metal-Oxide Transistor Biosensors for Metabolite Detection in Human Saliva

Metabolites are essential molecules involved in various metabolic processes, and their deficiencies and excessive concentrations can trigger significant physiological consequences. The detection of multiple metabolites within a non-invasively collected biofluid could facilitate early prognosis and diagnosis of severe diseases. Here, a metal oxide heterojunction transistor (HJ-TFT) sensor is developed for the label-free, rapid detection of uric acid (UA) and 25(OH)Vitamin-D3 (Vit-D3) in human saliva. The HJ-TFTs utilize a solution-processed In2O3/ZnO channel functionalized with uricase enzyme and Vit-D3 antibody for the selective detection of UA and Vit-D3, respectively. The ultra-thin tri-channel architecture facilitates strong coupling between the electrons transported along the buried In2O3/ZnO heterointerface and the electrostatic perturbations caused by the interactions between the surface-immobilized bioreceptors and target analytes. The biosensors can detect a wide range of concentrations of UA (from 500 nm to 1000 µM) and Vit-D3 (from 100 pM to 120 nm) in human saliva within 60 s. Moreover, the biosensors exhibit good linearity with the physiological concentration of metabolites and limit of detections of ≈152 nm for UA and ≈7 pM for Vit-D3 in real saliva. The specificity is demonstrated against various interfering species, including other metabolites and proteins found in saliva, further showcasing its capabilities.

Hybrid MoSe2/P3HT Transistor for Real-Time Ammonia Sensing in Biofluids

Organic and inorganic hybrid field-effect transistors (FETs), utilizing layered molybdenum diselenide (MoSe2) and an organic semiconductor poly(3-hexylthiophene) (P3HT), are presented for biosensing applications. A new hybrid device structure that combines organic (P3HT) and inorganic (MoSe2) components is showcased for accurate and selective bioanalyte detection in human bodily fluids to overcome 2D-transition metal dichalcogenides (TMDs) nonspecific interactions. This hybrid structure utilizes organic and inorganic semiconductors' high surface-to-volume ratio, carrier transport, and conductivity for biosensing. Ammonia concentrations in saliva and plasma are closely linked to physiological and pathological conditions of the human body. A highly sensitive hybrid FET biosensor detects total ammonia (NH4+ and NH3) from 0.5 μM to 1 mM concentrations, with a detection limit of 0.65 μM in human bodily fluids. The sensor's ammonia specificity in artificial saliva against interfering species is showcased. Furthermore, the fabricated hybrid FET device exhibits a stable and repeatable response to ammonia in both saliva and plasma, achieving a remarkable response level of 2300 at a 1 mM concentration of ammonia, surpassing existing literature by 10-fold. This hybrid FET biosensing platform holds significant promise for developing a precise tool for the real-time monitoring of ammonia concentrations in human biological fluids, offering potential applications in point-of-care diagnostics.