Biophysical Society Thematic Meeting - November 16-20, 2015

Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Speaker Abstracts

Calcium Phosphate Nanoparticle (CPNP)-entrapped Tetracycline: A Potential Drug against Diarrheal Diseases Tarakdas Basu , Riya Mukherjee. University of Kalyani, Kalyani, India. Diarrheal diseases, caused by bacterial genii Escherichia, Vibrio, Salmonella and Shigella, represent a major health problem in developing countries. The broad-spectrum antibiotic, tetracycline, was once the most effective drug against diarrhea. Emergence of bacterial resistance to tetracycline nowadays limits its use. In most cases, resistance generation is mediated by a family of cell membrane proteins, which block entry of tetracycline into cell cytosol. Therefore, to bring back obsolete tetracycline in further use, we venture to synthesize a nano-form of the antibiotic by loading it within calcium phosphate nanoparticle (CPNP), because CPNP has high membrane-penetrating and biodegradable properties and nowadays is used as a potential carrier of DNA, RNA, proteins and therapeutics into different cells. Nano-formulation was done through a co-precipitation method of preparation of CPNP, in presence of tetracycline, using calcium nitrate and di-ammonium hydrogen phosphate as precursors and Na-citrate as stabilizer. Synthesized Tet-CPNP was characterized by DLS, TEM, AFM, FTIR, EDS, spectrofluorimetry and dialysis techniques. Size of the spherical shaped NPs was 10-15nm. About 20% of the maximally added tetracycline (500µg/ml) was entrapped within CPNP. There was sustained release of entrapped tetracycline over seven days, implying higher antibacterial efficacies of Tet- CPNP. Bctericidal activity of nano-particulate tetracycline was investigated by agar plating, spectrophotometry, phage contrast-fluorescence microscopy and AFM technique. Minimum bactericidal concentrations of Tet-CPNP on multiple antibiotic (including tetracycline) resistant bacteria like Escherichia coli, Salmonella kentuckey and Shigella flexneri were 20-40µg/ml. NP- mediated cell filamentation and cell membrane disintegration caused cell killing. Death of Shigella-infected Zebra fish larvae was stalled by Tet-CPNP treatment. All these results implied that our nano-formulation might reclaim a nearly obsolete, cheap antibiotic to further potential function, making it highly useful to developing countries with limited health care budgets.

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