Bioconjugated Quantum Dots in Rapid Detection of Water Microbial Load: An Emerging Technology

Abstract

Drinking water contaminated with pathogenic living forms is a major concern for human health in developing countries because it can lead to acute and sometimes life-threatening gastrointestinal diseases. There is thus a need to detect potentially harmful pathogens and identify them in the presence of several other nonpathogenic microbes, particularly in the urban water systems to prevent infection and disease. Shiga toxin producing E. coli is one of the largest common pathogenic bacteria causing diarrhea. Salmonella typhimurium and Listeria monocytogenes are other microbes contaminating water. Immediate detection of these pathogens can help avoid infections. Nanomaterials have unique physical, optical, and electrical properties which can be employed for detection of pathogens. Quantum dots (QDs) are one such class deployed for rapid detection of pathogenic bacteria in water samples. QDs are preferred over the fluorescent organic dyes, as they display intense and stable fluorescence for a longer period of time; are resistant towards photo-bleaching; and provide a highly sensitive and specific detection of pathogens. Biosensors that help in rapid detection of pathogenic bacteria using fluorescent bioconjugated quantum dots (QDs) are reported. This chapter summarizes studies on use of QDs or QD-based biosensors for detection of waterborne pathogens and scope for future applications in the area.