We report results of the studies relating to the development of an efficient biosensor for non-invasive detection of CYFRA-21-1 cancer biomarker. We used a low dielectric constant material (nanostructured yttrium oxide, nY₂O₃) for the fabrication of the biosensing platform. The nY₂O₃ was synthesized via solvothermal process and functionalized using 3-aminopropyl triethoxy silane (APTES). Electrophoretic deposition (EPD) of the functionalized nanomaterial (APTES/nY₂O₃) onto an indium tin oxide (ITO)-coated glass electrode was conducted at a DC potential of 50 V for 60 s. The EDC-NHS chemistry was used for covalent immobilization of −COOH bearing monoclonal anti-CYFRA-21-1 onto −NH₂ groups of APTES/nY₂O₃/ITO electrode. To avoid the non-specific interaction on the anti-CYFRA-21-1/APTES/nY₂O₃/ITO immunoelectrode, bovine serum albumin (BSA) was used. X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM) were utilized for structural and morphological studies, whereas Fourier-transform infrared spectroscopy (FTIR) was used for the bonding analysis. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were used for electrochemical characterization and response studies of fabricated electrodes. The fabricated immunosensor (BSA/anti-CYFRA-21-1/APTES/nY₂O₃/ITO) exhibited linearity in the range of 0.01–50 ng·mL⁻¹, sensitivity of 226.0 Ω·mL·ng⁻¹, and lower detection limit of 0.01·ng·mL⁻¹. A reasonable correlation was observed between the results obtained using this biosensor and concentration of CYFRA-21-1 measured through ELISA (enzyme-linked immunosorbent assay) technique in salivary samples of oral cancer patients.

A portable bienzymatic biosensor enables rapid, non-invasive quantification of salivary glucose through colorimetric detection and derivative analysis for point-of-care diagnostics.

A portable optical biosensor was designed for non-invasive detection of glucose through saliva. In this approach, a biodegradable glucose test strip was fabricated by 3D printing to create a fluidic groove and was filled with a cellulose based sieving infill matrix, onto which, glucose oxidase (GOD)-peroxidase (POD) and O-dianisidine chromogenic dye were co-immobilized. The enzymatic reaction with saliva samples containing glucose produced H₂O₂ as an intermediate product with which dye reacted, leading to a colour change to reddish-brown in the detection zone, which was then quantified by the developed electronic meter. The meter featured an optically isolated section within the chassis for inserting the test strip and sample to prevent interference from external factors such as wind and ambient light. The biosensor exhibited a broad detection range spanning 21.7 to 225 mg/dL of glucose concentration, with a sensitivity of 12.58 sensor count/mgdL^-1 and a limit of detection (LOD) of 21.7 mg/dL within a response time of 2.5 minutes. The device and the strips were validated with clinical samples, comparing salivary glucose levels (SGL) with blood glucose levels (BGL) using a commercial glucometer. A good correlation was observed between SGL and BGL for diabetic/pre-diabetic subjects under fasting and post-prandial conditions as 0.99, 0.98 (p-values of 0.009 and 0.006); and for non-diabetic as 0.53 and 0.95 (p-values of 0.014, 0.007) respectively. The device also passed Clarke's error grid analysis, indicating its clinical acceptability. This low-cost, standalone, user-friendly device has thus the potential to revolutionize the self-monitoring of glucose in painless manner.

Non-communicable diseases such as diabetes and chronic kidney disease (CKD) are major global health concerns due to associated high morbidity rates. Conventional monitoring of these diseases typically involves invasive methods, which can be painful and inconvenient for patients. This study highlights the development of a non-invasive, handheld optical biosensor capable of multivariate analysis using saliva samples. The device used two distinct paper-fluidic strips designed with different enzyme–dye combinations to detect glucose and urea. The biosensor also used ambient temperature compensation to address the differential sensitivity of these sensors owing to variations caused by temperature-dependent enzyme kinetics, thereby enhancing the measurement accuracy. Biosensor characteristics with the glucose oxidase-based strip showed a sensitivity of 1.93 count per mg per dL, linearity range from 8 to 358 mg dL⁻¹, limit of detection (LOD) of 8 mg dL⁻¹, and response time of 7.35 s. The clinical validation shows good correlation between saliva glucose levels (SGLs) and blood glucose levels (BGLs). The urea biosensor strip shows a sensitivity of 1.51 count per mg per dL, LOD of 5 mg dL⁻¹, linearity range from 5 to 90 mg dL⁻¹, and response time of 3 s. The clinical validation for the CKD patient shows a significant correlation between blood urea levels and saliva urea levels. The results demonstrate that the device offers a rapid, reliable, and user-friendly alternative for point-of-care testing (POCT), potentially improving patient compliance and management of diabetes and CKD. Significance: The findings suggest that this technology could represent a significant advancement in non-invasive diagnostic tools and can be used as a POCT by chronic patients.

Parasitological investigation was conducted to assess the effects of various biotic factors viz. length, weight and age of host on the infection patterns of Filochona teleostei (Singh & Malik, 1992) in snow trout Schizothorax richardsonii (HAM.) from hill streams of Garhwal Himalayas. The statistical analysis was carried out to calculate infection incidence, mean worm burden, regression values and their significance. About 20% fishes (18% male and 22% female) were found infected with nematode parasites. Infection patterns of Filochona teleostei revealed a negative correlation (r= - 0.347 to - 0.734) with length, (r= - 0.499 to - 0.671) with weight and (r= - 0.576) with age of host fish. The age immunity and stronger host resistance developed by the larger fishes are the possible reasons for the decrease in infection in larger and older fishes.