Block Copolymer-Assembled Nanopores Enable Ultra-Sensitive Label-Free DNA Detection

DNA detection plays an important role in pathogen identification and disease diagnosis but is often limited by lenghty processing times, high costs, and the need for complex equipment and skilled personnel, making it less accessible in point-of-care and resource-limited environments. In this study, we introduce an electrode modification strategy for DNA detection that uses block copolymer-directed nanoporous thin films for nanopore blockage (NB)-based electrochemical biosensors. This approach enables rapid, label-free DNA detection and quantification at femtomolar levels. Deploying a bottom-up fabrication process that leverages on the self-assembly of high molecular weight block copolymers with inorganic sol-gel precursors, we create a highly scalable nanoporous thin film architecture with tailored pore size and arrangement. Crucially, we eliminate the need for complex fabrication including stacking brittle porous membranes, a constraint in existing NB-based DNA sensors. The rapid performance of this sensor is demonstrated by detecting specific single-stranded DNA sequences derived from the 16S rRNA gene fragment of the E. coli genome within 20 minutes, achieving a limit of detection of 30 fM and a limit of quantification of 500 fM. The development of this DNA biosensor represents a significant advancement towards a portable, user-friendly, rapid, cost-effective, and highly accurate DNA detection platform, promising to overcome current limitations of conventional detection methods and broadening the applicability of DNA diagnostics across diverse use cases.