Decoration, Characterization and Antimicrobial Activity Evaluation of Novel Nano-Based 1,2-Phenylenediamine Functionalized Maleic Anhydride-Allylphenyl Ether Conjugate

Abstract

1,2-Phenylenediamine (o-PDA) is a well-known fluorescent dye that enables the decoration of next generation chemotherapeutics. A novel o-PDA-functionalized maleic anhydride-allyl phenyl ether (poly(MA-alt-APE)/o-PDA conjugate) was successfully synthesized according to the Ringsdorf model, which is the starting point for macromolecular prodrugs. Functional polymeric-carriers were prepared by free-radical polymerization in butyl acetate with azobisisobutyronitrile (AIBN) radical-initiator at 70°C. The conjugation was carried out at 40°C in N,Ndimethylformamide (DMF) using triethylamine (Et3N) as the conjugation catalyst. Characterization was performed by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR), Nuclear Magnetic Resonance (1H-NMR), UV-Vis and Fluorescence Spectroscopy. Weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity index (PDI) (Mw/Mn) were calculated using gel permeation chromatography (GPC). The surface morphology was also elucidated by Transmission Electron Microscopy (TEM). Evaluation of antimicrobial activity against two Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus), two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and one yeast Candida albicans was performed using the broth microdilution method according to Clinical Laboratory Standards Institute (CLSI) criteria. Interestingly, S. aureus was found to be more sensitive to polymerbased samples and, in particular, the minimum inhibitory concentration (MIC) of the conjugate was lower than that of ciprofloxacin used as a control compound.