**Preface to "Biomedical and Pharmacological Applications of Marine Collagen"**

Biomimetic polymers and materials have been widely used in a variety of biomedical and pharmacological applications. Collagen-based biomaterials in particular have been extensively applied in various biomedical fields, for example, as scaffolds in tissue engineering. However, there are many challenges associated with the use of mammalian collagen, including the issues of religious constraints, allergic or autoimmune reactions, and the spread of animal diseases such as bovine spongiform encephalopathy, transmissible spongiform encephalopathy, and foot-and-mouth disease.

Over the past few decades, marine collagen has emerged as a promising biomaterial for biomedical and pharmacological applications. Marine organisms are a rich source of structurally novel and biologically active compounds, and to date, many biological components have been isolated from various marine resources. Marine collagen offers advantages over mammalian collagen due to its water solubility, easy extractability, low immunogenicity, safety, biocompatibility, biodegradability, antimicrobial activity, functionality, and low production costs. Due to its characteristics and physicobiochemical properties, it has tremendous potential for use as a scaffold biomaterial in tissue engineering and regenerative medicine, in drug delivery systems, and as a therapeutic agent.

In this book, some recent innovativeapplications of these proteins have been discussed that could potentially be applied in scientific and industrial research. This book covers recent trends in all aspects of basic and applied scientific research on marine collagen, with a particular focus on their biotechnological, biomedical and pharmacological uses.

> **Sik Yoon** *Editor*

### *Article* **Preparation and Characterization of Thermally Stable Collagens from the Scales of Lizardfish (***Synodus macrops***)**

**Junde Chen \*, Guangyu Wang and Yushuang Li**

> Technical Innovation Center for Utilization of Marine Biological Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China; 17859733637@163.com (G.W.); liyushuang@tio.org.cn (Y.L.) **\*** Correspondence: jdchen@tio.org.cn; Tel./Fax: +86-0592-215527

> **Abstract:** Marine collagen is gaining vast interest because of its high biocompatibility and lack of religious and social restrictions compared with collagen from terrestrial sources. In this study, lizardfish (*Synodus macrops*) scales were used to isolate acid-soluble collagen (ASC) and pepsinsoluble collagen (PSC). Both ASC and PSC were identified as type I collagen with intact triple-helix structures by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and spectroscopy. The ASC and PSC had high amino acids of 237 residues/1000 residues and 236 residues/1000 residues, respectively. Thus, the maximum transition temperature (Tmax) of ASC (43.2 ◦C) was higher than that of PSC (42.5 ◦C). Interestingly, the Tmax of both ASC and PSC was higher than that of rat tail collagen (39.4 ◦C) and calf skin collagen (35.0 ◦C), the terrestrial collagen. Solubility tests showed that both ASC and PSC exhibited high solubility in the acidic pH ranges. ASC was less susceptible to the "salting out" effect compared with PSC. Both collagen types were nontoxic to HaCaT and MC3T3-E1 cells, and ASC was associated with a higher cell viability than PSC. These results indicated that ASC from lizardfish scales could be an alternative to terrestrial sources of collagen, with potential for biomedical applications.

**Keywords:** lizardfish scale; marine collagen; thermal stability; cell viability
