Design of Stimuli-Responsive Cobalt Tetraphenylporphyrinate-Chitosan Microspheres for Advanced Biosensors

In this work, we report the synthesis of new cobalt tetraphenylporphyrinate-chitosan-based microspheres for application as biosensors and in anticancer therapy. These microspheres were characterized using optical microscopy, scanning and transmission electron microscopy, and X-ray powder diffraction. We analyzed their nonlinear optical behavior, specifically the second harmonic generation (SHG), employing a high-resolution SHG microscope, with the quadratic fits of the SHG intensities considered as a function of the excitation power, under optimized experimental conditions. Beyond the typical porphyrinate fluorescence, the microspheres exhibit the same peculiar SHG behavior as CoTPP powder, making them suitable as multibiosensors. Additionally, they exhibit the same laser-induced dynamic properties previously observed in CoTPP powder, indicating their promising potential for dynamic anticancer therapies. The results of this work are encouraging, highlighting the possible application of these microspheres as multibiosensors and anticancer agents.