Design of highly sensitive biosensors using hollow-core microstructured fibers for plasma sensing in aids with human metabolism.

Detection of low index liquid analytes in real-time, in-situ, and with high accuracy is of great importance in various scientific fields, particularly in medicine and biology. Accurate detection of plasma concentration in blood samples is one of the most significant usages of biosensors in medicine. In this paper, we report a highly sensitive biosensor using hollow core microstructure optical fibers (HC-MOFs) to detect low index liquid analytes with a particular focus on detection of plasma concentration in blood samples. We demonstrate how variations in plasma concentration in blood can change transmission spectra of the HC-MOF due to the photonic bandgap mechanism. We use the finite element approach to explore how the biosensor's performance depends on the number of capillary rings encircling the hollow core of the fibre. An average spectral and amplitude sensitivity of 8928.57 nm/RIU and 1.21 dB/RIU is reported for the optimized design of HC-MOF for five capillary rings with a refractive index detection range of 1.333 to 1.3385 for different ratios of plasma in blood serum. The proposed biosensor can have potential application in liquid analyte detection in medicine, chemistry, and biology where real-time and accurate data about liquid analytes are necessary for human metabolism.

The Henderson-Hasselbalch Equation : A Three Dimensional Teaching Model.

The Henderson-Hasselbalch equation can be considered as the backbone of acid base physiology. This is conventionally represented using two dimensional plots. Although two dimensional plots are simple to use, the equation in reality represents a surface in three dimensional space. Any combination of PaCO2, [HCO3 ­] and blood pH values representing acid base disorders is restricted to this surface. Two models depicting the three dimensional surface generated by the Henderson-Hasselbalch equation were constructed from easily available materials. The first model was constructed using coloured beads, thin metal rods and plywood. This model depicted the Henderson-Hasselbalch surface as a collection of discreet points. The second model depicted the Henderson-Hasselbalch equation as a continuous surface using polystyrene sheets and white cement. The models were presented to undergraduate and post-graduate medical students along with other conventional two dimensional nomograms. Three dimensional models of the Henderson-Hasselbalch equation can serve as supplementary teaching material to ensure a deeper understanding of acid base physiology.