NIR Laser Integration of Photodetector on 3D Printed Chamber for Colorimetric Biosensing

In this work, gold nanoparticles (Au NPs)/indium-zinc-oxide (IZO) nanocomposite visible photodetector (PD) is directly prepared by near-infrared (NIR) laser-annealing on a 3D-printed substrate to form an integrated colorimetric sensor. After a surface planarization process, using a low power laser treatment without damaging the substrate, Au NPs are formed from the Au thin layer (6 nm) on 3D-printed resin substrate by laser-assisted dewetting process. Also, the UV–vis photoresponsivity is compared by tuning different NIR laser power intensity for sol-gel IZO curing. By investigating the temperature profile of each laser annealing process and the surface morphology of Au NPs/IZO nanocomposite film, the optimized PD is then integrated with a 3D-printed sensing chamber for successfully demonstrating urea detection varied from 1, 5, 10, 25 and 50 × 10⁻³ m, which refer to the salivary urea concentrations for healthy and chronic kidney disease groups.