Laser-induced graphene wet transfer technique for lab-on-chip applications

Due to its simple and cost-effective manufacturing process, Laser-Induced Graphene (LIG) has opened up possibilities for intriguing electronic applications in various contexts, including Lab-On-Chip scenarios. This attractive material can be produced on multiple organic substrates, but the most common are PolyImide sheets, which are generally less versatile than other plastic substrates. Moreover, they are opaque to multiple wavelengths in visible light, limiting their applicability in experiments that require a completely transparent material. For this reason, we developed a new and cheap transfer protocol, which exploits the partial solubility of thermoplastic substrates in a solvent to make them infiltrate the LIG, peeling it off from PolyImide. After focusing on transferring LIG on Poly Methyl Metacrylate substrates, the protocol has been optimized to minimize the transferred LIG (t-LIG) sheet resistance. The obtained material is then characterized by its morphology, electrode capabilities, and biocompatibility. Finally, t-LIG was simulated and used to apply an electric field in a Lab-OnChip designed for microparticle manipulation by dielectrophoresis. The obtained results demonstrated the great potential of t-LIG in Lab-On-Chip and biological experiments, suggesting new exciting applications that rely on both optical and electrical investigations.