Direct laser scribing of AgNPs@RGO biochip as a reusable SERS sensor for DNA detection

The combination of surface-enhanced Raman spectroscopy (SERS) technology with microfluidics makes it possible to diagnose genetic disease through label-free on-chip DNA detection. However, open problems including the integration of SERS substrate with microfluidic devices, controllable trapping and releasing of target molecules are still challenging. Here we demonstrate a facile laser scribing method to fabricate silver nanoparticles (AgNPs) and graphene oxide (GO) based biochips as a reusable SERS sensor for DNA detection. Programmable laser scribing of the AgNPs@GO composite film enables direct patterning of sensitive SERS channels that consist of graphene supported AgNPs by exfoliating the composites into hierarchical porous structures. Integrating the SERS-active patterns with a microfluidic chip forms a biochip for allowing SERS detection of DNA. The noncovalent interactions between DNA and graphene mediated controllable trapping and releasing of DNA sequences, enabling efficient on-chip SERS detection and the regeneration of the biochip. The simple, green and cost-effective fabrication of the SERS-active biochips reveals great potential for biomolecular sensing and genetic engineering applications.