κ-Carrageenan Gel Modified Mesoporous Gold Chronocoulometric Sensor for Ultrasensitive Detection of MicroRNA
Bidita Salahuddin, Mostafa Kamal Masud, Shazed Aziz, Chia-Hung Liu, Nasim Amiralian, Aditya Ashok, Sakiat Hossain, Hyeongyu Park, Md A. Wahab, Mohammed A. Amin, M. Adharvana Chari, Alan E. Rowan, Yusuke Yamauchi, Md. Shahriar A. Hossain, Yusuf Valentino Kaneti
Abstract
Abstract Hydrogel-functionalized surface-based transducers demonstrate fluid-like kinetics, non-fouling properties, and superior biocompatibility. The integration of such properties of three-dimensional (3D) micro- or macrostructure of hydrogels into a mesoporous platform provides a favorable moiety for incorporating biomolecule for adsorption or hybridization with a capture agent. Herein, we report a novel κ-carrageenan hydrogel-coated mesoporous gold (Au) electrode (abbreviated as MPGE/gel) for chronocoulometric (CC) detection of microRNA (miRNA). The κ-carrageenan gel provides a 3D porous network on Au electrode surface to enable higher adsorption of target miRNA for CC interrogation of miRNA in presence of a redox molecule-ruthenium hexaammine (III) chloride ([Ru(NH3)6]3+, RuHex). Magnetically isolated and purified target miR-9-2 is adsorbed onto the MPGE via Au-RNA affinity interaction through the porous 3D network of the gel followed by the CC detection. The enhanced miRNA adsorption and electrocatalytic activity of MPGE/gel provide attomolar (50 aM) level of detection of miRNA with a dynamic range from 100 pM to 10 aM. The good reproducibility (% RSD ≤ 5%, for n = 3) and high specificity of the developed biosensor demonstrates its excellent translational potential toward developing precisely controlled sensing devices for current clinical needs.