SYNTHESIS AND EVALUATION OF MODIFIED POLYDOPAMINE NANOPARTICLES FOR BIOMEDICAL APPLICATIONS

Abstract

Polymeric nanoparticles have provided for an answer to many biomedical queries and diagnosis and treatment of the diseases can be carried out with their help. In this study, polydopamine was used as the parent polymer which was modified to fulfill two aims of the project, i.e. gene delivery as well as antimicrobial activity. For gene therapy, efficient delivery of DNA to cells is the primary concern. An efficient carrier must have a good stability, transfection efficiency and minimal toxicity. One such example of polymeric vector is branched polyethylenimine (bPEI). It is regarded by the scientists as the ―gold standard for gene delivery‖ but suffers a major drawback of high cytotoxicity. Here, we have attempted to develop nanoparticles by choosing a mussel-derived polymer, polydopamine (PDA) cross-linked with polyethylenimine in such a way that the toxic nature of bPEI is suppressed by the conversion of free primary amine groups to secondary and tertiary amines. Keeping the amount of PDA fixed, varying amounts of bPEI (10 kDa and 1.8 kDa) are linked. We observed a trend in hydrodynamic size with changing ratio of PEI onto PDA ranging from 160-300 nm and zeta potential from +12-30 mV in the developed two series – 1) PDA1:10bPEI0.5, PDA1:10bPEI1, PDA1:10bPEI2 and 2) PDA1:1.8bPEI0.5, PDA1:1.8bPEI1, PDA1:1.8bPEI2. A visible trend in the DNA condensation ability and buffering capacity is also reported. Further, we report that pDNA complexes of PDA-PEI nanoparticles are non-toxic to mammalian cells and exhibit higher transfection than the native PEI. Further for antimicrobial study, polydopamine was modified by using three antibiotic aminoglycosides which were- gentamicin sulfate, kanamycin sulfate and neomycin sulfate hydrate. Their antibacterial activity against some strains like S.aureus, K.pneumoniae, P.aeruginosa and B.cereus was tested and evaluated by zone inhibition method. To sum up, the developed nanoparticles can be effectively used for further in vivo applications.