Glucosamine/β-Alanine Carbon Dots Use as DNA Carriers Into E. coli Cells

Abstract

Introducing foreign DNA into bacterial cells is essential in functional genomics and molecular research. Currently, heat shock and electroporation are the two major techniques of gene delivery in bacterial cells. However, both the techniques are time and resource consuming and are limited to a few species or strains of bacteria and there is a need to develop new transformation alternatives. Carbon dots with unique features such as facile synthesis, ease of functionalization, nontoxicity, and biocompatibility are considered novel biomolecule nanocarriers. In this study, we synthesized and evaluated DNA delivery potential of four carbon dots including: 1) amine-coated carbon dots (NH2-FCDs); 2) carboxylate carbon dots (COOH-FCDs); 3) L-arginine and glucose carbon dots (N-CDs), and 4) citric acid and polyethyleneimine (PEI) carbon dots into Escherichia. coli cells. We evaluated the minimum incubation time required for the plasmid DNA delivery and the maximum plasmid size that can be delivered into E. coli cells using these CDs. Bacteria were incubated with carbon dots solution for different lengths of time and plated on selection media. Transformed colonies were counted and data were analyzed to identify the optimum incubation time and measure DNA delivery of these CDs with plasmids of different sizes. Our study demonstrated that among all these CDs, only carboxylate carbon dots (COOH-FCDs) prepared from glucosamine and β-alanine were able to deliver plasmid DNA into E. coli cells and the best incubation time was between 30 and 60 min. The maximum plasmid size that could be delivered using these CDs was approximately 10 kb and transformation efficiency decreased with larger plasmids. This study shows the capacity of COOH-CDs to deliver plasmid DNA into bacteria with an immense potential to combine with modern genome-editing tools. However, further studies are needed to evaluate their potential in DNA delivery in other bacterial strains.

Novel Synthesis of Carbon Dots from Coconut Wastes and Its Potential as Water Disinfectant

“…The CDs without any surface modification showed 4.89% toxicity. On the other hand, CDs modified with PEI did not show any cytotoxicity against E. coli, which can be compared with the findings of Devkota et al [44], who synthesized…”

“…The CDs without any surface modification showed 4.89% toxicity. On the other hand, CDs modified with PEI did not show any cytotoxicity against E. coli, which can be compared with the findings of Devkota et al [44], who synthesized amine-functionalized carbon dots with PEI and found no antimicrobial effect on bacterial species like Agrobacterium, Salmonella, Pectobacterium and E. coli. Hence, our study showed that doping with urea during CD synthesis contributed to favorable surface modifications in CDs and exhibited antibacterial properties when compared to other doping agents such as PEI and HMTA (Table 4).…”

Structure–Property–Activity Relationships in Carbon Dots

“…Extensive literature studies demonstrate that the CDs applied to gene delivery normally contain abundant amine groups resulting in CDs with positive surface charges, which promotes their binding to negatively charged nucleic acids by electrostatic interactions. 168 To prepare positively charged CDs, polyethylenimine (PEI), polyethylene glycol (PEG), polyethylene diamine (PAMAM), chitosan, and poly-L-lysine are frequently used as precursors or grafted on the surface of CDs. 169 Among them, PEI as a commercial transfection reagent is popular in the development of cationic CDs and gene delivery applications.…”