Investigation of glucose-induced thermo-optical and polarizability effects in blood plasma for optical biomolecular differentiation.

This work presents a preliminary study using an opto-mechatronic system to measure the refractive index and thermo-optical behavior of blood plasma. The setup employs a 650 nm laser and a displacement sensor on a linear actuator to detect beam deviation through small fluid volumes. Using water-based fluids with different glucose levels, a linear decreasing trend in refractive index with temperature was observed. Furthermore, plasma samples with different glucose concentrations were evaluated across a temperature range. One sample, corresponding to a markedly elevated glucose level, exhibited a dual thermo-optical response that suggests a transition to a different optical regime influenced by complex biomolecular composition. To contextualize these findings, numerical modeling under high irradiance was incorporated as a conceptual framework to explore how thermo-optical properties may evolve under stronger light-matter interactions. The simulations indicate that both glucose concentration and molecular polarizability can modulate the thermo-optical coefficient under nonlinear conditions. Rather than demonstrating molecular specificity, these results serve as initial evidence that optical parameters are sensitive to plasma composition and may guide future studies aimed at establishing selective, light-based biochemical analysis.