Fabrication of chitin-chitosan/nano ZrO(2) composite scaffolds for tissue engineering applications
Authors: Sowmya Srinivasan
H Tamura
P T Sudheesh Kumar
V V Divyarani
K P Chennazhi
S V Nair
R Jayakumar
Roshni Ramachandran
Journal: International Journal of Biological Macromolecules (2011)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: tissue engineering; chitin; chitosan; nano ZrO(2); scaffold
Affiliations: Amrita Centre for Nanosciences, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham, Kochi, India. 

Abstract:  The urge to repair and regenerate natural tissues can now be satisfactorily fulfilled by various tissue engineering approaches. Chitin and chitosan are the most widely accepted biodegradable and biocompatible materials subsequent to cellulose. The incorporation of nano ZrO(2) onto the chitin-chitosan scaffold is thought to enhance osteogenesis. Hence a nanocomposite scaffold was fabricated by lyophilization technique using chitin-chitosan with nano ZrO(2). The prepared nanocomposite scaffolds were characterized using SEM, FTIR, XRD and TGA. In addition, the swelling, degradation, biomineralization, cell viability and cell attachment of the composite scaffolds were also evaluated. The results demonstrated better swelling and controlled degradation in comparison to the control scaffold. Cell viability studies proved the non toxic nature of the nanocomposite scaffolds. Cells were found to be attached to the pore walls and spread uniformly throughout the scaffolds. All these results suggested that the developed nanocomposite scaffolds possess the prerequisites for tissue engineering scaffolds and could be used for various tissue engineering applications. 

Retracted: No

PubPeer comments:
 There are some unexpected similarities between figures in this paper and another paper by partially overlapping authors, i.e. R. Jayakumar et al. International Journal of Biological Macromolecules (2011), doi: 10.1016 j.ijbiomac.2010.12.010. This paper here studied ZrO2 nanoparticles. The other paper studied TiO2 nanoparticles. Yet, some figure look unexpectedly similar. Here is a comparison between Figure 1 of this paper and Figure 2 of the TiO2 paper. Similar spectra representing different compounds are shown with red and blue boxes. ![file] , 
 A panel in Figure 2 of this paper appears to look very similar to two panels (a and b) of Figure 3 of the TiO2 paper. Shown with aqua boxes. ![file] , 
 Panel d of Figure 6 looks very similar to panel d of Figure 9 of the TiO2 paper. Shown with orange boxes. (that paper appears to have a duplication shown in pink boxes, but that is not relevant for this paper). ![file] , 
 A re-do of Figure 2 of this paper compared to Figure 3 of the TiO2 paper. ![file] , 
 Corrected [15 August 2019] . --------------------------------- In the original manuscript, FTIR spectrum of chitinu2013chitosanu2013ZrO2 (Fig. 1A) was inadvertently provided with spectrum of chitinu2013chitosan. The experiment was re-performed and the rectified Fig. 1 is provided below. In the original manuscript text 3.1 Characterization u201cHowever no specific bands corresponding to ZrO2 were observed which could be due to the absence of any chemical reaction between chitinu2013chitosan and ZrO2, respectively.u201d should be read as u201cthe characteristic peaks of ZrO2 were found at 746u202fcmu22121 corresponding to the monoclinic structure of ZrO2 and peaks at 552u202fcmu22121 and 643u202fcmu22121 corresponds to the tetragonal structure of ZrO2 were present in the FTIR spectra of chitinu2013chitosanu2013nanoZrO2 scaffolds.u201d ![] Further, in the original manuscript, the SEM images of chitinu2013chitosan scaffolds (Fig. 2a b) were provided incorrectly. We re-performed the experiment and the corrected Fig. 2 is provided below. ![] The changes in these figures would not affect the overall conclusion of this manuscript. The authors would like to apologise for any inconvenience caused. ,