Amphiphilic carbon dots as versatile vector for nucleic acid and drug delivery
Carbon dots (CD)-based multifunctional delivery system has shown great potential in both drug/gene delivery and bio-imaging. In this work, we present a strategy to simply construct amphiphilic CD (ACD) by conjugating hydrophobic alkyl epoxide to the surface amino groups of PEI 600-derived CD. ACD could well dissolve in water or organic solvents and emit bright fluorescence both in solutions and cells. 1HNMR also suggested that ACD may form micelle-like structure in water, and its CMC could be determined. Enhanced green fluorescent protein (EGFP) expression and flow cytometry experiments showed that ACD has higher transfection efficiency than Lipofectamine 2000 in A549 cells. Besides DNA, ACD could also effectively transfect Sur siRNA toward A549 cells and cause early cell apoptosis. The 3D multicellular spheroids further confirmed its high potential for delivering therapeutic gene into the tumor tissue. On the other hand, ACD also exhibited good drug loading ability. CLSM experiment results showed that DOX could be effectively internalized by the cell and slowly released from the drug/ACD complex. These results suggest that ACD may not only serve as a versatile delivery vector with potential for applications in clinical cancer treatment, but also offer an inspiration for the discovery of CD-based gene/drug delivery system.