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Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Speaker Abstracts
36
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.