Dual Functional Carbon Quantum Dots: Novel Tools for DNA Delivery in Bacterial Transformation and as Antimicrobial Agents Against Gram-Negative Bacteria
Successful delivery of plasmid DNA into bacterial cells is fundamental in recombinant DNA technology. Natural transformation in bacteria is limited due to the repulsive forces between negatively charged DNA and bacterial membrane. Most common DNA delivery systems in bacteria includes artificial transformation through heat shock and electroporation. These methods rely on preparation of competent cells which are either time consuming or rely on sophisticated instruments. Similarly, multi-drug resistance in bacteria is a major public health concern. Apart from their ability to deliver DNA into the cells, carbon dots are gaining popularity as a new source of antimicrobial agents due to their ability to inhibit the microbial growth and their non-toxicity to different mammalian cells. Here we are reporting the synthesis of carbon dots (CDs) using Citric acid and Beta-Alanine, their use in DNA delivery and as antimicrobial agent in a diverse species of gram-negative bacteria. CDs were fabricated using microwave assisted synthesis. Plasmids carrying RFP as a reporter gene and ampicillin resistance gene were used as selectable markers in bacterial transformation. Our findings indicate that CDs can be used successfully in delivery of foreign DNA of 10kb size into E. coli. Also, antibacterial activity of these CDs was studied using well-diffusion method and minimal inhibitory concentration was determined by incubating bacteria with different concentration of CDs ranging from 0.5 to 10 mg/mL for 20 hrs. Our finding indicates that these CDs can be considered as an effective alternative to common antibiotics. We also demonstrated that the antimicrobial properties of these CDs are dependent on the incubation time and bacterial species where some species can be inhibited in a shorter time than others. With minimum of 5 hours incubation time, P. carotovorum and P. aeruginosa strains were the most sensitive species whereas E. coli and S. enterica strains were the most resistant bacteria requiring over 16 hours of incubation with CDs.
"Dual Functional Carbon Quantum Dots: Novel Tools for DNA Delivery in Bacterial Transformation and as Antimicrobial Agents Against Gram-Negative Bacteria"
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