Optimized Flexible Microheater With Integrated Electrodes and Microchannel for On-Chip Bacterial Incubation and Electrochemical Detection

Abstract

The exponential rise in antimicrobial resistance (AMR) has gained growing interest in developing point-of-care devices capable of conducting inexpensive on-site bacterial infection testing. While these systems aim to incorporate more complex diagnostic methods into simple portable chips, they remain tethered to laboratory incubators requiring high-power inputs. Even though bacterial incubators play a vital role in providing optimal growth conditions for bacterial culture, they lack portability, which restricts their utility in real-time applications. A simple, flexible, portable incubation system holds significant potential for developing point-of-care kits. Herein, a flexible silver ink-based resistive microheater has been fabricated using inkjet printing. The fabricated microheater serves a multifaceted purpose, allowing for efficient growth conditions for culturing bacteria, their on-site quantification, and antibiotic susceptibility testing. The in-house fabricated microheater has been successfully employed for bacteria culturing at $37~^{\circ }$ C and developing a bacteria-on-chip platform for AMR detection. The microheater performance has been parametrically optimized using Multiphysics simulations and the design of experiments. The results obtained have been highlighted, achieving an appropriate incubation temperature of 37°C at an electric potential as low as 1.5 V with minimal thermal loss, ensuring superior temperature uniformity for 72-hour incubation and costing less than US 0.25 (₹ 20). Further, the fabricated microheater is reusable, stable, and water-resistant and has significant potential for developing affordable and turnkey point-of-care diagnostic kits for real-time applications.