Electrical antimicrobial susceptibility testing based on aptamer-functionalized capacitance sensor array for clinical isolates

Abstract

capacitance changes. As a result, bacterial activities, such as growth and death, can be monitored in real-time by measuring the capacitance change, allowing more rapid AST 23,24. For AST of clinical samples, it is necessary to simultaneously test various antimicrobial agents at different concentrations; therefore, we fabricated sensor arrays consisting of 60 sensors. Among the 60 sensors, two and three sensors were used for negative and positive controls, respectively, and the other 55 sensors were used to measure the antibiotic susceptibility to 11 antibiotics at five different concentrations (see Supplementary Table S1). To evaluate the performance of the eAST system, 30 clinical strains, most of which are frequently found in sepsis, were tested (Table 1). The categorical agreement between the eAST system and gold standard broth microdilution (BMD) test was estimated to be 97%, meeting the requirements of the United States Food and Drug Administration (FDA). Materials and methods fabrication of eAST chip. The eAST chip, consisting of 60 sensors, was fabricated on a glass substrate (Fig. 1). Each sensor had interdigitated Au electrodes with a width of 20 µm and spacing of 20 µm, which were patterned by conventional photolithography and lift-off techniques. For bacterial culture, a 300 μl-acrylic well (Nobel Biosciences Inc., Hwaseong-Si, South Korea) was attached to the array sensor using 3 M VHBTM tape. Next, the bacteria-aptamers were immobilized on the sensor surface.

Nanomotion Detection-Based Rapid Antibiotic Susceptibility Testing

“…Growth of cells is monitored by detecting capacitance change of bacteria bound to 60 aptamer-functionalized capacitance sensors [46] Mechanical-based AST methods…”

Aptamer-based biosensors for the diagnosis of sepsis

“…Patients' survival could be highly improved if they received timely and effective antibiotic treatment, but antimicrobial susceptibility test (AST) results usually require more than three days with conventional methods [80][81][82]. In addition to the quantitative and qualitative detection of bacteria, the aptamer sensor can monitor the real-time growth of bacteria and biofilm, which continuously and timely evaluate the internal infections and the effectiveness of antibiotics [46,47]. For instance, Song et al developed a vertical capacitance aptamer-functionalized sensor (Fig.…”

“…This study demonstrated that an aptamer-functionalized sensor could be used as an alternative tool for detecting bacteria and rapid AST in positive blood culture without the need for sub-culturing. Furthermore, Lee et al developed an electrical AST (e-AST) system, which shortens the AST time to only 6 h [47]. The e-AST system was composed of 60 aptamerfunctionalized capacitance sensors, of which 2 sensors were used for the negative control, 3 sensors for positive control, and other 55 sensors for the determination of antibiotic sensitivity to 11 antibiotics at 5 different concentrations.…”

Diagnostic clinical microbiology

“…Susceptibility results were available in <90 min. Lee et al (2020) reported on electrical antimicrobial susceptibility testing based on aptamer‐functionalized capacitance sensor array. Results were reported within 6 h. The electrical AST (e‐AST) is based on an array of 60 aptamer‐functionalized capacitance sensors, and the susceptibility comparisons were with broth microdilution.…”