کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
869997 | 909846 | 2006 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: PEMC sensor's mass change sensitivity is 20 pg/Hz under liquid immersion PEMC sensor's mass change sensitivity is 20 pg/Hz under liquid immersion](/preview/png/869997.png)
To enhance the mass change sensitivity of the resonating piezoelectric-excited millimeter-sized cantilever (PEMC) sensors, we reduced its length and eliminated one layer of its composite structure. As a result the mass sensitivity of the second flexural mode increased by two orders of magnitude (from 10−9 to 10−11 g/Hz) and the resonant frequency increased by more than 5 kHz. We demonstrate the effects of modification by detecting a model pathogen Group A Streptococcus (GAS) at 700 cells/mL. The resonant frequency change of the second mode at concentrations of 700, 7 × 103, 7 × 105, 7 × 106, 7 × 107, and 7 × 109 cells/mL resulted in, respectively, 3.1 ± 0.5, 11.6 ± 1, 15.7 ± 1, 25.7 ± 0.15, 28.5 ± 2, and 40.5 ± 3 ng (n = 3 for all) of pathogen attachment. A kinetic model for the binding is proposed and verified. The observed binding rate constant was found to be in the range of 0.051–0.166 min−1. The significance of the results we report is that the modified PEMC sensors have high mass sensitivity that pathogens can be detected at very low concentration under liquid immersion conditions.
Journal: Biosensors and Bioelectronics - Volume 22, Issue 1, 15 July 2006, Pages 35–41