Clam-inspired nanoparticle immobilization method using adhesive tape as microchip substrate

Immobilization of the suspended nanoparticles is essential for many microfluidic applications. This work reports a novel biomimetic method to immobilize nanoparticles by using a common adhesive tape as the substrate of microfluidic chip. It mimics the clams' feeding system that utilizes the mucus (i.e., sticky fluid) to capture small phytoplankton particles in water. This work proves experimentally that this method has a better immobilization effect and a stronger shear stress resistance than the traditional methods using hard glass substrates. Moreover, we have applied this method to immobilize Au nanorods for the detection of R6G of various concentrations using the surface-enhanced Raman scattering (SERS) effect. This method enjoys several major merits: the sticky adhesive tape can seal the microfluidic structure easily, avoiding the bonding process; the immobilization is easy and environmental friendly, without the need for expensive reagents or complex processes; the adhesive tape substrate allows the flexibility of microfluidic chips; and the adhesive tape substrate can be stripped off for off-chip detection and can be replaced easily for the reuse of microfluidic structures. With these, the biomimetic method may find potential applications in environmental sensing, biocatalysis and biosynthesis using microchips.