3D Pt/Graphene foam bioplatform for highly sensitive and selective in-situ adsorption and detection of superoxide anions released from living cells

A 3D sensing platform comprising Pt particles on graphene foam (Pt@GF) with well-defined surface and interface properties is developed to realize in-situ monitoring of superoxide anion (O-2(center dot-)) released from cells. It has found that Pt particles-impregnated 3D GF renders rich positively charged sites to enable strong O-2(center dot-) adsorption, which greatly enhances sensitivity towards O2 center dot- detection. Compared with 2D Pt@graphene sheet, the 3D Pt@GF is much more electrochemically active with a 6.5-time lower charge transfer resistance. Additionally, the porous 3D structure of Pt@GF promotes the attachment and growth of cells, providing a biocompatible platform to directly grow cells (cells@Pt@GF) for in-situ molecular sensing. Due to the merits mentioned above, the 3D cells@Pt@GF bioplatform as an in-situ O-2(center dot-) biosensor achieves a high sensitivity (1597.17 mu A nM(-1) cm(-2)), low detection limit (10 nM), fast response (3.6 s) and good selectivity. In particular, this detection limit is the best among all reported in-situ O-2(center dot-) biosensors with cells directly growing on the platforms. This work provides a 3D superior bioplatform for sensitive and selective in-situ molecular detection, and the design strategy combing 3D GF and active materials with well-defined surface properties holds great promise for the development of advanced next generation 3D devices for biomedical applications.