The need of cheap and easy to use biosensors for rapid diagnostics is a crucial challenge in medicine: indeed, devices must offer multiple properties such as fast response, high sensitivity, reduced need of sample processing, etc. In this respect, optical biosensors remain a promising class of biodevices. Here we present an extensive investigation of the surface properties of silver-coated zinc oxide disordered nanostructures as efficient biosensing platform to detect complex organic profiles via Raman spectroscopy. In particular, we combine low temperature and large area manufacturing techniques to offer a low-cost tool for rapid detection of untreated organic samples like human blood avoiding the usage of expensive manufacturing methods to grow ordered nanostructures and providing safer materials respect the implementation of metal nanoparticles thus opening the possibility to adopt these devices also in vivo. After an accurate study using rhodamine, comparing Raman response for as deposited and lasered surfaces, different metal layers (gold vs silver) and different metal thicknesses (from 25 to 150 nm), we successfully validate the performance of the silver-coated lasered platform on untreated human blood obtaining high resolved response and identifying several organic signatures attributable to hypoxanthine, glucose and lipoprotein.

Background Aim of this study was to investigate the retrograde axonal transport from optic nerve (ON) to retinal ganglion cell (RGC) in two animal models: in Royal College of Surgeons (RCS) rats, a rat model for retinal degeneration, and in a rat model for glaucoma induced by elevated intraocular pressure (IOP). Methods To carry out this study, dextran tetramethylrhodamine (DTMR- an hydrophilic neurotracer dye) was injected into the ON; 24 hrs later, the retina was removed and the number of labeled RGCs of the experimental rats was counted and compared. Results The results of these studies showed that the number of fluorescent-labeled RGCs in RCS rats and in rats with elevated IOP was reduced compared to the number of labeled RGCs of their respective controls. Conclusion Our findings suggest that RCS rats are characterized not only by loss of photoreceptor cells but also by functional deficits of RGCs.