Synthesis, characterization and cytocompatibility studies of α-chitin hydrogel/nano hydroxyapatite composite scaffolds
Authors: Sowmya Srinivasan
S V Nair
H Tamura
Vinoth-Kumar Lakshmanan
R Jayakumar
P T Sudheesh Kumar
Journal: International Journal of Biological Macromolecules (2011)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: α-chitin; hydrogel; nano hydroxyapatite; composite scaffold; freeze-drying
Affiliations: Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi 682041, India.

Abstract:  α-chitin hydrogel/nano hydroxyapatite (nHAp) composite scaffold have been synthesized by freeze-drying approach with nHAp and α-chitin hydrogel. The prepared nHAp and nanocomposite scaffolds were characterized using DLS, SEM, FT-IR, XRD and TGA studies. The porosity, swelling, degradation, protein adsorption and biomineralization (calcification) of the prepared nanocomposite scaffolds were evaluated. Cell viability, attachment and proliferation were investigated using MG 63, Vero, NIH 3T3 and nHDF cells to confirm that the nanocomposite scaffolds were cytocompatible and cells were found to attach and spread on the scaffolds. All the results suggested that these scaffolds can be used for bone and wound tissue engineering. 

Retracted: No

PubPeer comments:
 Two panels in Figure 6, panel G (7 days) and H (14 days) appear to show an overlap. Shown with light blue boxes. In addition these panels also appear to show an overlap with a panel in a different paper by the same authors, i.e. Kumar et al. (2011) Carbohydrate Polymers, 85(3), 584-591.t DOI: 10.1016 j.carbpol.2011.03.018 The panels appear to represent different concentrations of nHAp. Shown with dark blue light blue boxes. ![file] , 
 Figures 10, 11, and 12 of this paper also appear to show some panels that look similar, although they represent different cell lines. , 
 Figures 10, 11, and 12 of this paper also appear to show some panels that look similar, although they represent different cell lines. ![file] , 
 Figure 3 of this paper shows remarkable similarities to Figure 1 of another paper from the same author, ie. Kumar et al. Carbohydrate Polymers (2011) - doi: 10.1016 j.carbpol.2011.03.018 issn: 0144-8617. See: https: pubpeer.com publications 67AC992930284A6276E31AED852712 While this paper is based on alpha-chitin scaffold, the other paper is based on beta-chitin scaffolds. Could the authors explain why 1 SEM photo and several spectra all look so similar? ![file] , 
 Figure 6 of this paper appears to contain two panel that looks similar to each other, even though they represent 2 different time points (shown in blue). In addition, they also look similar to a panel in Figure 3 of the same paper as mentioned in #1. Shown here in blue. Note that the blue boxes represent different concentrations of nHAp in these 2 figures. ![file] , 
 Figure 10, 11, and 12 of this paper appear to show some panels that look very similar to each other. ![file] , 
 Correction, [1 October 2019] . ------------------------------------------ In the original manuscript, Fig. 3A the SEM image of u03b1-chitin control scaffold is incorrect. This mistake has been rectified and the corrected Fig. 3 is presented below. ![] In the original manuscript, the biomineralization results shown in Fig. 6Eu2013I are inadvertently arranged which can be attributed to mistakes in assembling the figures. The corrected Fig. 6 is shown below. ![] In the original manuscript, Fig. 9D is inadvertently repeated as Fig. 9F. Thus we have re-performed the entire cell attachment experiment using SEM imaging (Fig. 9Au2013F). In addition, the DAPI images of 1% nHAp incorporated u03b1-chitin scaffolds (Fig. 12I and L) were provided for the same material without the nHAp. Therefore we redid the entire cell attachment experiment in HDF using DAPI. Further, Fig. 12C was wrongly placed in the original manuscript. The corrected Fig. 9, Fig. 12 are shown below. ![] *Fig. 9. SEM images of cell attachment and DAPI images with MG63. A, B and C are SEM images of cell attachment of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp scaffolds respectively at 12u202fh and D, E and F are SEM images of cell attachment of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp scaffolds respectively at 72u202fh. G, H and I are DAPI images of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp scaffolds respectively at 12u202fh and J, K and L are DAPI images of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp scaffolds respectively at 72u202fh.* ![] *Fig. 12. SEM and DAPI images of cell attachment of scaffolds with HDF. A, B and C are SEM images of cell attachment of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp scaffolds respectively at 12u202fh and D, E and F are SEM images of cell attachment of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp scaffolds respectively at 72u202fh. G, H and I are DAPI images of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp scaffolds respectively at 12u202fh and J, K and L are DAPI images of u03b1-chitin control, u03b1-chitinu202f+u202f0.5% nHAp and u03b1-chitinu202f+u202f1% nHAp composite scaffolds respectively at 72u202fh.* These changes in the figures would not affect the conclusion from the figure nor the overall conclusion of the whole manuscript. The authors would like to apologise for any inconvenience caused. ,