Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON K7L 3N6, Canada.
Biosensors (Basel). 2022 Mar 25;12(4):194. doi: 10.3390/bios12040194.
This paper presents a dynamic-mode microcantilever sensor based on a gap method. The sensor has a V-shaped microcantilever and a fixed structure at a distance of 2 µm from its free end. The microcantilever is excited by applying an ac electric potential (3 V) to its piezoelectric pads and vibrates at its fundamental resonant frequency. An independent ac electric potential (200 kHz, 15 V) is applied to the fixed structure. This creates a non-uniform electric field with its maxima at the gap and exerts a dielectrophoresis (DEP) force. The DEP force attracts and adsorbs the bacteria to the cantilever edge at the gap. The binding of the bacteria to the cantilever creates a shift in the resonant frequency of the microcantilever sensor, which is detected by a laser vibrometer. The real-time detection of bacteria samples, diluted in distilled water, was performed for concentrations of 10-10 cells/mL and the real-time frequency shifts were -2264.3 to -755 Hz in 4 min, respectively. The tests were expanded to study the effect of the electric potential amplitude (10, 12, 15 V) and higher frequency shifts were observed for higher amplitudes.
本文提出了一种基于间隙法的动态模式微悬臂梁传感器。该传感器具有 V 形微悬臂梁和与其自由端相距 2 µm 的固定结构。微悬臂梁通过在其压电片上施加交流电势（3 V）来激励，并以其基频共振。向固定结构施加独立的交流电势（200 kHz，15 V）。这会在间隙处产生不均匀的电场，产生介电泳（DEP）力。DEP 力将细菌吸引并吸附到间隙处的悬臂边缘。细菌与悬臂的结合会导致微悬臂梁传感器的共振频率发生偏移，这可以通过激光测振仪来检测。对在蒸馏水中稀释的细菌样品进行了实时检测，浓度分别为 10-10 细胞/mL，在 4 分钟内实时频率偏移分别为-2264.3 至-755 Hz。测试范围扩大到研究电势幅度（10、12、15 V）的影响，观察到更高的幅度会产生更高的频率偏移。
