Detection of Salmonella typhi utilizing bioconjugated fluorescent polymeric nanoparticles
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Present work demonstrates effective utilization of functionalized polymeric fluorescent nanoparticles as biosensing probe for the detection of Salmonella typhi bacteria on modified polycarbonate (PC) filters in about 3 h. Antibody modified-PC membranes were incubated with contaminated bacterial water for selective capturing which were detected by synthesized novel bioconjugate probe. Core–shell architecture of polymeric nanoparticles endows them with aqueous stabilization and keto-enolic functionalities making them usable for covalently linking S. typhi antibodies without any crosslinker or activator. Bradford analysis revealed that one nanoparticle has an average of 3.51 × 10−19 g or 21 × 104 bound S. typhi Ab molecules. Analysis of the regions of interest (ROI) in fluorescent micrographs of modified fluoroimmunoassay showed higher detection sensitivity of 5 × 102 cells/mL due to signal amplification unlike conventional naked dye FITC-Ab conjugate. Fluorescence of pyrene dye remained same on immobilization of biomolecules and nanoparticles showed stable fluorescent intensity under prolong exposure to laser owing to protective polymeric layer allowing accurate identification of bacteria. Surface-functionalized PC matrix and fluorescent label NPs permit covalent interactions among biomolecules enhancing signal acquisitions showing higher detection efficiency as compared to conventional microtiter plate-based system. Our novel immunoassay has the potential to be explored as rapid detection method for identifying S. typhi contaminations in water.
KeywordsFluoroimmunoassay Fluorescent nanoparticles Salmonella typhi ELISA Detection Bioconjugation Health safety
Fluorescent polymeric nanoparticles
Acetoacetoxy ethyl methacrylate
- S. typhi
This work was supported by Department of Biotechnology (DBT), Govt. of India; authors duly acknowledge their generous financial support. The authors are also thankful to CSIR-UGC and ICMR, India for their research fellowships.
- Chen L, Zhang J (2012) Bioconjugated magnetic nanoparticles for rapid capture of gram-positive Bacteria. J Biosens Bioelectrons 11:005Google Scholar
- Chumyim P, Rijiravanich P, Somasundrum M, Surareungchai W (2014) Detection of Salmonella enterica serovar Typhimurium in milk sample using electrochemical immunoassay and enzyme amplified labeling. Int Conf Agric Environ Biol Sci 24–25 PhukeGoogle Scholar
- Qui D, He X, Wang K, Zhao X, Tan W, Chen J (2007) Fluorescent nanoparticle-based indirect immunofluorescence microscopy for detection of Mycobacterium tuberculosis. J Biomed Biotechnol 7:89364–89370Google Scholar
- Yaohua H, Chengcheng W, Bing B, Mintong L, Wang R, Li Y (2014) Detection of Staphylococcus aureus using quantum dots as fluorescence labels. Int J Agric Biol Eng 7:77–81Google Scholar
- Yu H, Bruno JG (1996) Immunomagnetic-electrochemiluminescent detection of Escherichia coli O157 and Salmonella typhimurium in foods and environmental water samples. Appl Environ Microbiol 62:587–592Google Scholar