A Biosensor System for the Detection of Salmonella Typhimurium Using Multiple Phage-based Magnetoelastic Biosensors
- PDF / 764,448 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 7 Downloads / 192 Views
1253-K11-08
A biosensor system for the detection of Salmonella typhimurium using multiple phage based magnetoelastic biosensors Wen Shen1, Yugui Li2, Huiqin Chen2, Shin Horikawa1 and Bryan Chin1 1 Materials Research & Education Center, Auburn University, Auburn, AL 36849, U.S.A. 2 School of Material Science and Engineering, Taiyuan University of Science and Technology, Taiyuan, 030024, P. R. China
ABSTRACT Magnetoelastic (ME) sensors provide a fast, sensitive method to detect bacteria with smaller sensors have higher mass sensitivity for detecting lower concentrations of bacteria. However, signals from smaller sensors are weaker and have more noise due to manufacturing defects. In this paper, we present a biosensor system for the detection of Salmonella typhimurium using multiple magnetoelastic sensors, each with the size of 2000 × 400 × 30 µm. The sensors are immobilized with E2 phage, which specifically binds with S. typhimurium. Unlike traditional methods, our system uses a step pulse to “shock” the sensor, causing it to vibrate at its natural resonance frequency and produce a signal in the pickup coil due to reverse magnetostriction. A Fast Fourier Transform (FFT) was used to determine the resonance frequency. As the biosensor captures S. typhimurium cells, its mass increases with a corresponding decrease of its resonance frequency. The detection system was composed of one coil with a reference sensor to monitor stability, and another coil with three measurement sensors separated in three tubes for simultaneous detection of bacteria. With multi-sensors the effect of a manufacturing defect is decreased and we get the benefit of averaging for more accurate and reliable results. Stability tests show that the variance of frequency detection is less than 122 ppm of its resonance frequency. SEM pictures of the sensor surface show a uniform binding of S. typhimurium cells. Cells were counted and the mass change calculated. The measured frequency change corresponds well to the theoretical change. The results show that the multiple phage based ME biosensors are able to simultaneously detect S. typhimurium and offer good sensitivity and reliability of detection. INTRODUCTION Magnetoelastic (ME) resonance sensors provide a fast, sensitive method to detect bacteria and spores1-3. Previous study shows that higher mass sensitivity for detecting lower concentration of bacteria can be achieved by reducing the sensor sizes4. However, as sensor sizes become smaller, the signals from the sensors are weaker and sometimes have more noise due to manufacturing defects. This results in less accuracy in the detection of resonance frequencies and lower sensitivity of the sensor. In this paper, we present a biosensor system that uses pulse method for the detection of the resonance frequency of the sensors. Unlike traditional methods, this method uses a step pulse to “shock” the sensor into vibration at its natural resonance frequency. The shape change of the ME sensors occurred during their vibration causes a signal in the pickup coil d
Data Loading...
