Background: Bio-molecule based carbon dots (C-dots) have gained much attention in last few years due to their high biocompatibility, low toxicity and outstanding optical properties which can possibly be used as nano-carrier for drug delivery.Methodology: To find out the best possible conditions for carbon dots preparation from xylitol different combinations of process conditions were evaluated. Synthesized carbon dots were purified and evaluated for their size, surface features, and luminescence by AFM, FT-IR and spectrophoto-fluorometry. Purified C-dots were loaded with conventional antimicrobial compounds and evaluated against clinical isolates of human pathogens.
Results:Xylitol and its C-dots were effective against E. coli, S. pyogenes, C. albicans and Cryptococcus neoformans while no activity was recorded against Staphylococcus aureus, Klebsiella pneumonia, Listeria monocytogenes, and Salmonella typhi. In contrast to this conjugates were more effective than conventional antimicrobials. MIC analysis with respect to the four selected pathogens showed that vary small concentration of Am-C dots is sufficient to inhibit the growth of pathogens as 0.01 mg/ml of Am-C dots was sufficient against S. pyogenes but 0.16 mg/ml xylitol and 0.08 mg/ml antimicrobial respectively were required. Similarly 0.16 mg/ml (Escherichia coli), 0.04 mg/ml (Candida albicans & Cryptococcus neoformans) were sufficient which is quite low in terms of concentration in comparison to crude form of antimicrobials and xylitol itself.
Conclusion:The results pertaining to current work further suggested that C-dots were not only found more effective but also improved the efficacy of conventional antimicrobials used against the pathogens. Such potential of this important low calorie sweetener can be exploited in variety of healthcare products after further R&D and clinical trials. The efficiency of xylitol C-dots and the conjugates with positive antimicrobials (tetracycline and ketoconazole) against several pathogens also exhibited the useful role of nanotechnology in healthcare.