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Published on: October 26, 2016
Synthesis, Characterization, and Multifunctional Applications of Chitosan-Grafted-Poly(Acrylic
Asaad H Alzaidy1, Safaa H Ganduh2, Murtadha Saleh Hussien2
1Department of Laboratory and Clinical Science, College of Pharmacy, University of Al-Qadisiyah, Diwaniyah, Iraq.
Background:
Effective wound dressings must combine antimicrobial action with support of tissue repair. Chitosan hydrogels are biocompatible but weakly antimicrobial, whereas ZnO nanoparticles are potent antimicrobials that need a carrier matrix. Most studies address either loading chemistry or biological performance, rarely both. Here, the ZnO-loading chemistry of a CH-g-P(AA-co-Am)/ZnO nanocomposite hydrogel is linked to its biological behaviour.
Methods:
The hydrogel was synthesised by free-radical graft copolymerisation (potassium persulfate initiator, N,N'-methylenebisacrylamide crosslinker), loaded with ZnO nanoparticles and characterised by FTIR, XRD, FE-SEM, TEM, AFM, EDX and TGA. ZnO loading was studied in batch experiments. Antimicrobial activity (S. aureus, E. coli, A. niger), wound healing (full-thickness excisional wounds in BALB/c mice; 24 animals in four groups of six) and cytotoxicity (A172 glioblastoma cells and the WRL68 reference line, MTT assay) were assessed.
Results:
ZnO nanoparticles (20-50 nm) were uniformly dispersed in the network; EDX gave 4.3 wt% zinc, and T9 5% rose from 198.9 to 242.1°C. The nanocomposite swelled by 130.77%. Loading followed pseudo-second-order kinetics (R2 = 0.9966) and the Freundlich isotherm (R2 = 0.916), with a Langmuir-derived reference capacity of 18.35 mg/g. Loading was endothermic (ΔH = +49.19 kJ/mol) yet spontaneous (ΔG = -2.10 kJ/mol), hence entropy-driven, consistent with mixed physical and coordinative binding of Zn2⁺ to carboxylate groups that governs zinc release. The nanocomposite gave inhibition zones of 24 ± 0.8 mm (S. aureus), 22 ± 0.6 mm (E. coli) and 25 ± 0.8 mm (A. niger) and 98.7 ± 1.1% wound closure by day 14. IC5 0 values against A172 were 94.97 (hydrogel) and 71.05 µg/mL (nanocomposite); IC5 0 ratios relative to WRL68 were 1.79 and 2.41. As WRL68 is HeLa-derived and ZnO may interfere with tetrazolium readouts, these values indicate a differential response, not tumour selectivity.
Conclusion:
The CH-g-P(AA-co-Am)/ZnO nanocomposite combines controlled zinc loading, antimicrobial activity and effective wound healing in one platform, supporting its potential as a multifunctional wound dressing.
