Three-dimensional mesoporous gold film to enhance the sensitivity of electrochemicaldetection

Abstract

Cell–cell and cell–extracellular matrix (ECM) adhesion are fundamental andimportant in the development of a cell-based chip. In this study, a novel, simple,rapid, and one-step technique was developed for the fabrication of a uniformthree-dimensional mesoporous gold thin film (MPGF) onto a gold (Au) coatedglass plate based on an electrochemical deposition method. Scanning electronmicroscopy images demonstrated that the resulting MPGF electrode had uniformlydistributed pores with diameters of about 20 nm. The cyclic voltammetric behavior of[Fe(CN)6]4 − /3 − coupled onto MPGF and Au electrodes demonstrated that the MPGF electrode had ahigher electrocatalytic sensitivity and reversibility than the bare Au electrode. TheArg–Gly–Asp (RGD) sequence containing the peptide was immobilized on theMPGF and bare Au substrates. HeLa cancer cells were then cultured on theRGD peptide layer. The successful immobilization of the peptide and cells wasconfirmed by atomic force microscopy. The cell proliferation and viability wereevaluated by cyclic voltammetry and Trypan blue dyeing assay. These resultsindicated that the RGD/MPGF modified electrodes showed an electrochemicalsensitivity in the detection of cancer cells which is approximately three times higher,especially at low cell density, than RGD/Au electrodes. This much improvedsensitivity of the MPGF modified electrode demonstrates the potential for thefabrication of a highly sensitive and low-cost cell-based chip for rapid cancer detection.