Evaluation of wound healing potential of Œ≤-chitin hydrogel/nano zinc oxide composite bandage
Authors: Raja Biswas
Shantikumar V Nair
Rangasamy Jayakumar
Tamura Hiroshi
Sudheesh Kumar P T
Mincy Raj
Vinoth-Kumar Lakshmanan
Journal: Pharmaceutical Research (2013)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: Œ≤-chitin hydrogel; nZnO composite bandage; blood clotting; platelet activation; antibacterial activity
Affiliations: Amrita Centre for Nanosciences and Molecular Medicine Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, 682041, India.

Abstract:  Purpose: Œ≤-chitin hydrogel/nZnO composite bandage was fabricated and evaluated in detail as an alternative to existing bandages. Methods: Œ≤-chitin hydrogel was synthesized by dissolving Œ≤-chitin powder in Methanol/CaCl(2) solvent, followed by the addition of distilled water. ZnO nanoparticles were added to the Œ≤-chitin hydrogel and stirred for homogenized distribution. The resultant slurry was frozen at 0¬∞C for 12 h. The frozen samples were lyophilized for 24 h to obtain porous composite bandages. Results: The bandages showed controlled swelling and degradation. The composite bandages showed blood clotting ability as well as platelet activation, which was higher when compared to the control. The antibacterial activity of the bandages were proven against Staphylococcus aureus (S. aureus) and Escherichia coli (E.coli). Cytocompatibility of the composite bandages were assessed using human dermal fibroblast cells (HDF) and these cells on the composite bandages were viable similar to the Kaltostat control bandages and bare Œ≤-chitin hydrogel based bandages. The viability was reduced to 50-60% in bandages with higher concentration of zinc oxide nanoparticles (nZnO) and showed 80-90% viability with lower concentration of nZnO. In vivo evaluation in Sprague Dawley rats (S.D. rats) showed faster healing and higher collagen deposition ability of composite bandages when compared to the control. Conclusions: The prepared bandages can be used on various types of infected wounds with large volume of exudates. 

Retracted: No

PubPeer comments:
 This paper has a Corrigendum. Of note, several papers from this research group have recent corrections and errata. Most of these appear to correct duplicated panels. The text of this Corrigendum reads:  In the original manuscript, the platelet activation images of the sample treated groups, Fig. 3c were provided incorrectly. Due to this mistake, we have re-performed the experiments in entire groups and the corrected Fig. 3 is given below. In the original manuscript, Fig. 7a is incorrect. We rectified this mistake and the corrected Fig. 7 is presented below. These changes in the figures would not affect the overall conclusion of the whole manuscript. The authors would like to apologize for any inconvenience caused. I thank the authors for correcting these figures. , 
 Before correction, several panels in Figure 3 appear to look similar to panels in two other figures by the same research group. Each experiment appears to be different. Here is a comparison of the 3 figures: * Figure 3 in Pharm Res (2013) 30:523u2013537 DOI 10.1007 s11095-012-0898-y (this paper) * Figure 5 in ACS Appl. Mater. Interfaces (2012) 45:2618-2629 DOI: 10.1021 am300292v * Figure 5 in Journal of biomedical nanotechnology (2012) 8(6), 891-900.DOI: 10.1166 jbn.2012.1461  , 
 Figure 8 of this paper shows a wound-healing experiment in which three panels, shown in red, blue, and yellow boxes show similarity to panels in Figure 11 of another paper by the same group, i.e. Kumar et al. Tissue Engineering Part A (2013) - doi: 10.1089 ten.tea.2012.0376. Could the authors clarify if these were the same rats and same experimental conditions? It is unexpected to see the same wound photos in multiple papers, especially since there were 6 rats in each group.  , 
 Figure 10 of this paper shows some possible similarities to Figure 15 of the same Tissue Engineering paper as mentioned above. Could the authors clarify if they used the same rats to serve as the control group in both papers?  ,