Development of an integrated label-free electrochemical sensor with sample collection for the detection of Acinetobacter baumannii

Abstract

Acinetobacter, a genus of bacteria capable of infecting humans, is found in the healthcare environment. Acinetobacter baumannii (A. baumannii), which is one of the most important species in the genus Acinetobacter, causes bloodstream, wound, and pneumonia infections in immunocompromised patients. This bacterium adapts to various conditions and develops antibiotic resistance, making it challenging to manage in healthcare settings. In this study, an integrated label-free electrochemical sensor was developed for the detection of A. baumannii non-coding RNA (ncRNA). This integrated sensing platform, consisting of two parts: the sample collection unit and the detection electrode, has been developed. The sample collection was fabricated from paper for collecting the sample and integrated with a heating probe for lysing the bacteria and releasing the ncRNA. The detection mechanism relies on the hybridization of the bacterial ncRNA to the thiolated complementary sequences immobilized on the sensor surface. The sensor employed a three-electrode chip and square wave voltammetry (SWV). The increase in the current due to the hybridization event with the target ncRNA was quantified. To create a user-friendly sensor, sample collection pads were integrated with the electrochemical sensor, which was subsequently employed to collect and identify bacteria from contaminated surfaces. The developed sensor exhibits high selectivity and sensitivity, with a 5 pM limit of detection (LoD) and 15 pM limit of quantification (LoQ), respectively. It has been demonstrated that the sensor has the capability to detect non-coding RNA from A. baumannii in samples from cell cultures. This sensor offers a promising approach for direct bacterial detection in a single device, eliminating the need for multiple pre-test steps or DNA amplification.