Type II acid soluble collagen (CIIA), pepsin soluble collagen (CIIP) and type II gelatin (GII) were isolated from silvertip shark (Carcharhinus albimarginatus) cartilage and examined for their physicochemical and antioxidant properties. GII had a higher hydroxyproline content (173 mg/g) than the collagens and cartilage. CIIA, CIIP and GII were composed of two identical α1 and β chains and were characterized as type II. Amino acid analysis of CIIA, CIIP and GII indicated imino acid contents of 150, 156 and 153 amino acid residues per 1000 residues, respectively. Differing Fourier transform infrared (FTIR) spectra of CIIA, CIIP and GII were observed, which suggested that the isolation process affected the secondary structure and molecular order of collagen, particularly the triple-helical structure. The denaturation temperature of GII (32.5 °C) was higher than that of CIIA and CIIP. The antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl radicals and the reducing power of CIIP was greater than that of CIIA and GII. SEM microstructure of the collagens depicted a porous, fibrillary and multi-layered structure. Accordingly, the physicochemical and antioxidant properties of type II collagens (CIIA, CIIP) and GII isolated from shark cartilage were found to be suitable for biomedical applications.

The development of biomaterials with the potential to accelerate wound healing is a great challenge in biomedicine. In this study, four types of samples including pepsin soluble collagen sponge (PCS), acid soluble collagen sponge (ACS), bovine collagen electrospun I (BCE I) and bovine collagen electrospun II (BCE II) were used as wound dressing materials. We showed that the PCS, ACS, BCE I and BCE II treated rats increased the percentage of wound contraction, reduced the inflammatory infiltration, and accelerated the epithelization and healing. PCS, ACS, BCE I, and BCE II significantly enhanced the total protein and hydroxyproline level in rats. ACS could induce more fibroblasts proliferation and differentiation than PCS, however, both PCS and ACS had a lower effect than BCE I and BCE II. PCS, ACS, BCE I, and BCE II could regulate deposition of collagen, which led to excellent alignment in the wound healing process. There were similar effects on inducing the level of cytokines including EGF, FGF, and vascular endothelial marker CD31 among these four groups. Accordingly, this study disclosed that collagens (PCS and ACS) from tilapia skin and bovine collagen electrospun (BCE I and BCE II) have significant bioactivity and could accelerate wound healing rapidly and effectively in rat model.

The instability of metal halide perovskites upon exposure to moisture or heat strongly hampers their applications in optoelectronic devices. Here, we report the large-yield synthesis of highly water-resistant total-inorganic green luminescent CsPbBr 3 /CsPb 2 Br 5 core/shell heteronanocrystals (HNCs) by developing an in situ phase transition approach. It is implemented via water-driven phase transition of the original monoclinic CsPbBr 3 nanocrystal and the resultant tetragonal CsPb 2 Br 5 nanoshell has small lattice mismatch with the CsPbBr 3 core, which ensures formation of an epitaxial interface for the yielded CsPbBr 3 /CsPb 2 Br 5 HNCs.These HNCs maintain nearly 100% of the original luminescence intensity after immersion in water for eleven months and the luminescence intensity drops only to 81.3% at 100 °C. The transient luminescence spectroscopy and density functional theory calculation reveal that there 1 are double radiative recombination channels in the core CsPbBr 3 nanocrystal, and the electron potential barrier provided by the CsPb 2 Br 5 nanoshell significantly improves the exciton recombination rate. A prototype quasi-white light-emitting device based on these robust CsPbBr 3 /CsPb 2 Br 5 HNCs is realized, showing their strong competence in solid-state lighting and wide color-gamut displays.

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Aquatic origin collagen (Aqua-collagen) has been pursued as an alternative to mammalian origins. Acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were successfully extracted from the skin of tilapia with the yield about 19-20% (basis of lyophilized dry weight), and examined for their physico-functional and structural properties. Both ASC and PSC containing α 1 , α 2 chains were characterized to be type I collagen and had lower denaturation temperature compared to mammalian origins. PSC (low telopeptides collagen) was selected for biomedical scaffolds construction due to its low immunogenicity. SEM analysis of fish collagen scaffolds showed a wide range of pore size distribution, high porosity, and high surface area-to-volume ratios. The tilapia collagen microfiber matrix scaffolds were grafted beneath the dorsal skin in 96 mice towards tissue regeneration, with bovine collagen microfiber matrix scaffolds (Avitene™ UltraFoam™ sponge) serving as control. Biocompatibility evaluation in the dorsal tissue showed that implanted scaffolds degraded completely after 20 days with no pathological inflammatory tissue responses. These findings indicated that aqua-collagens microfiber matrix scaffolds were highly biocompatible in nature, exploring its feasibility for the development of scaffolds in tissue engineering. 1. Introduction Collagen is one of non-branched chain fibrous proteins in the extracellular matrix (ECM) component, plays a pivotal role in maintaining tissue homeostasis, biological integrity and structural mechanics [1]. Collagen, up to 25% of the total proteins, being presence in skin, bone, muscle sheath, ligaments, cartilage and other connective tissues of animals [2], is contributing to unique physiological functions [3]. Generally, collagens are formed by polypeptide chains constituted by repeating triplets Gly-X-Y of Glycine and two other amino acids, where proline (Pro) and hydroxyproline (Hyp) are the most common ones among about 1000 total amino acids [4]. Currently, researchers have identified at least 27 variants of collagens on the basis of sequence homology and the molecular structure [5]. Type I was the most abundant and important collagen and was a natural macromolecular hydrocolloid with widespread use in the food, cosmetic, biomedical, and pharmaceutical industries because of its excellent biocompatibility and biodegradability, and weak antigenicity [6]. Type I collagen was most prevalent and found in connective tissues such as bone, skin, and cornea of the eyes [7], contains three α chains such as [α 1 (I)] 2 α 2 (I) and [α 1 (I)] 3. Every chain contains more than 1000 amino acids with minor difference in amino acid sequences of α chains between different vertebrates. There has a repetition of glycine in every three amino acid sequence, such sequences make the distance of α chain shortened and the space minimized, so the chains close together to form a more stable helical structure since glycine has the smallest side groups. Marine and aquaculture capture fisheries are widely dist...

Collagen is the most abundant extracellular fibrous protein that has been widely used for biomedical applications due to its excellent biochemical and biocompatibility features. It is believed that the smaller molecular weight collagen, i.e., collagen peptide (CP), has more potent activity than native collagen. However, the preparation of CP from fish bone collagen is a complex and time-consuming process. Additionally, the osteogenic effect of CP depends on its molecular weight and amino acid composition. Considering the above concept, the present work was undertaken to extract the CP directly from Mahi mahi fish (Coryphaena hippurus) bones and test its osteogenic potential using bone marrow mesenchymal stem (BMMS) cells. The hydrolyzed collagen contained triple alpha chains (110 kDa) and a peptide (~1 kDa) and the peptide was successfully separated from hydrolyzed collagen using molecular weight cut-off membrane. CP treatment was up-regulated BMMS cells proliferation and differentiation. Interestingly, CP accrued the mineral deposition in differentiated BMMS cells. Protein and mRNA expression revealed that the osteogenic biomarkers such as collagen, alkaline phosphatase, and osteocalcin levels were significantly increased by CP treatment in differentiated BMMS cells and also further elucidated the hypothesis that CP was upregulated osteogenesis through activating Runx2 via p38MAPK signaling pathway. The above results concluded that the CP from Mahi mahi bones with excellent osteogenic properties could be the suitable biomaterial for bone therapeutic application.

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