Abstract

Recent use of biological warfare (BW) agents has led to a growing interest in the rapid and sensitive detection of pathogens. Therefore, the development of field-usable detection devices for sensitive and selective detection of BW agents is an important issue. In this work, we report a portable biochip system based on complementary metal oxide semiconductor (CMOS) technology that has great potential as a device for single-bacteria detection. The possibility of single-bacteria detection is reported using an immunoassay coupled to laser-induced fluorescence (LIF) detection. Bacillus globigii spores, which are a surrogate species for B. anthracis spores, were used as the test sample. Enzymatic amplification following immunocomplex formation allowed remarkably sensitive detection of B. globigii spores, and could preclude a complicated optical and instrumental system usually required for high-sensitive detection. Atomic force microscopy (AFM) was employed to investigate whether B. globigii spores detected in the portable biochip system exist in single-cell or multicellular form. It was found that B. globigii spores mostly exist in multicellular form with a small minority of single-cell form. The results showed that the portable biochip system has great potential as a device for single-particle or possibly even single-organism detection.

Keywords: Biological warfare reagents; Immunoassay; Biochip; High sensitivity

Article Outline

1. Introduction

2. Experimental

2.1. Capillary inner wall for immunoassay

2.2. ELISA

2.3. Instrumentation

2.4. AFM measurements

3. Results and discussion

3.1. Construction of highly sensitive biochip based on ELISA

3.2. Bacteria detection in the laser probe volume

3.3. AFM study

4. Conclusions

Acknowledgements

References