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Dopamine-Mediated Sclerotization of Regenerated Chitin in Ionic Liquid - PubMed

  • ️Tue Jan 01 2013

Dopamine-Mediated Sclerotization of Regenerated Chitin in Ionic Liquid

Dongyeop X Oh et al. Materials (Basel). 2013.

Abstract

Chitin is a promising structural material for biomedical applications, due to its many advantageous properties and abundance in nature. However, its usage and development in the biomedical field have been stagnant, because of chitin's poor mechanical properties in wet conditions and the difficulties in transforming it into an applicable form. To overcome these challenges, we created a novel biomimetic chitin composite. This regenerated chitin, prepared with ionic liquid, showed improved mechanical properties in wet conditions by mimicking insect cuticle and squid beak sclerotization, i.e., catechol-meditated cross-linking. By ionic liquid-based heat treatment, dopamine oxidation produced melanin-like compounds and dopamine-meditated cross-links without any solvent evaporation and oxidant utilization. The dopamine-meditated sclerotization increased the ultimate tensile strength (UTS) of the regenerated chitin by 2.52-fold, measured after six weeks of phosphate-buffered saline (PBS) submersion. In addition, the linear swelling ratio (LSR) of the chitin film was reduced by about 22%. This strategy raises a possibility of using regenerated chitin as an artificial hard tissue in wet conditions.

Keywords: dopamine; ionic liquid; mechanical properties; regenerated chitin; sclerotization; water-absorption.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1

Nitrogen 1s narrow scans in X-ray photoelectron spectroscopy (XPS) spectra of (A) pure chitin; (B) non-heat-treated 10 wt % dopamine-containing composite; and (C) 10 wt % dopamine-containing composite. Carbon 1s narrow scans in XPS spectra of (D) pure chitin; (E) non-heat-treated 10 wt % dopamine-containing composite; and (F) 10 wt % dopamine-containing composite.

Figure 2
Figure 2

(A) Water contact angle; (B) equilibrium water content (EWC); and (C) linear swelling ratio (LSR) values of pure regenerated chitin, 5 wt % dopamine-containing composite and 10 wt % dopamine-containing composite. Each value represents the mean of five analyses and its standard deviation.

Figure 3
Figure 3

(A) X-ray diffraction (XRD) spectra of native chitin (black curve), pure regenerated chitin (red curve), 10 wt % dopamine-containing composite (blue curve); scanning electron microscope (SEM) images of (B) pure regenerated chitin; and (C) 10 wt % dopamine-containing composite.

Figure 4
Figure 4

(A) Strain-stress curves of pure regenerated chitin (black curve), 5 wt % dopamine-containing composite (red curve) and 10 wt % dopamine-containing composite (blue curve); (B) Young’s modulus; and (C) ultimate tensile strength (UTS) values of pure regenerated chitin, 5 wt % dopamine-containing composite and 10 wt % dopamine-containing composite depending on submersion time in phosphate-buffered saline (PBS).

Figure 5
Figure 5

Comparison of MC3T3 cell proliferation on pure regenerated chitin (black); 10 wt % dopamine-containing composite (blue); and negative control (red, culture dish).

Figure A1
Figure A1

Pure regenerated chitin film (A) and 10 wt % dopamine-containing composite (B).

Figure A2
Figure A2

Carbon 1s narrow scans in XPS spectra of extracted melanin-like compound from 10 wt% dopamine containing composite (A) and Sepia melanin (control, B).

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