The Development and Applications of Collagen-Based Biomedical Materials and Its Relevant Theory

In this paper,the structure and properties of collagen,the rationale of collagen modification,the isoelectric point theory of collagen and its aggregation,and the multi-level collagen aggregates and its level division methods,etc,are clarified systematically.Meanwhile,the development progress of colla-

Polycaprolactone strengthening keratin/ bioactive glass composite scaffolds with double cross-linking networks for potential application in bone repair

In this study, we aimed at constructing polycaprolactone (PCL) reinforced keratin/bioactive glass composite scaffolds with a double cross-linking network structure for potential bone repair application. Thus, the PCL-keratin-BG com-posite scaffold was prepared by using keratin extracted from wool as main organic component and bioactive glass (BG) as main inorganic component, through both cross-linking systems, such as the thiol-ene click reaction between abundant sulfhydryl groups of keratin and the unsaturated double bond of 3-methacryloxy propyltrimethoxy silane (MPTS), and the amino-epoxy reaction between amino groups of keratin and the epoxy group in (3-glycidoxymethyl) methyldiethoxysilane (GPTMS) molecule, along with introduction of PCL as a reinforcing agent. The success of the thiol-ene reaction was verified by the FTIR and 1H-NMR analyses. And the structure of keratin-BG and PCL-keratin-BG composite scaffolds were studied and compared by the FTIR and XRD characterization, which indicated the successful preparation of the PCL-keratin-BG composite scaffold. In addition, the SEM observation, and contact angle and water absorption rate measurements demonstrated that the PCL-keratin-BG composite scaffold has interconnected porous structure, appropriate pore size and good hydrophilicity, which is helpful to cell adhesion, differentiation and prolifera-tion. Importantly, compression experiments showed that, when compared with the keratin-BG composite scaffold, the PCL-keratin-BG composite scaffold increased greatly from 0.91 ± 0.06 MPa and 7.25 ± 1.7 MPa to 1.58 ± 0.21 MPa and 14.14 ± 1.95 MPa, respectively, which suggesting the strong reinforcement of polycaprolactone. In addition, the biomineralization experiment and MTT assay indicated that the PCL-keratin-BG scaffold has good mineralization abil-ity and no-cytotoxicity, which can promote cell adhesion, proliferation and growth. Therefore, the results suggested that the PCL-keratin-BG composite scaffold has the potential as a candidate for application in bone regeneration field.

Bletilla striata polysaccharide modified collagen fiber composite sponge with rapid hemostasis function

Emergencies often result in uncontrollable bleeding, which is thought to be the leading cause of death at the scene of the injured. Among various hemostasis scenarios, collagen fiber (CF) is gradually replacing traditional hemostatic materials due to its superior properties and ease of sourcing from animals. Herein, we use CF and the natural herba-ceous Bletilla striata as raw materials to prepare a collagen fiber-oxidized Bletilla striata composite hemostatic sponge (CFOB). During the cross-linking process, the triple helix structure of collagen stays intact, and its porous three- dimensional network structure brings excellent bulkiness and water absorption properties. Experiments show that the optimal amount of sponge CFOB-10, namely oxidized Bletilla striata polysaccharide 0.5 mg/mL and CF 5 mg/mL, only needed 25 ± 4.06 s for hemostasis time in the rat liver hemorrhage model. In addition, CFOB meets the safety performance requirements of cytotoxicity classification standard 0. Therefore, the optimal amount of CFOB is an excel-lent new hemostatic material with application potential.

Advances on the modification and biomedical applications of acellular dermal matrices

Acellular dermal matrix(ADM)is derived from natural skin by removing the entire epidermis and the cell components of dermis,but retaining the collagen components of dermis.It can be used as a therapeutic alternative to“gold standard”tissue grafts and has been widely used in many surgical fields,since it possesses affluent predominant physicochemical and biological characteristics that have attracted the attention of researchers.Herein,the basic science of biologics with a focus on ADMs is comprehensively described,the modification principles and technologies of ADM are discussed,and the characteristics of ADMs and the evidence behind their use for a variety of reconstructive and prosthetic purposes are reviewed.In addition,the advances in biomedical applications of ADMs and the common indications for use in reconstructing and repairing wounds,maintaining homeostasis in the filling of a tissue defect,guiding tissue regeneration,and delivering cells via grafts in surgical applications are thoroughly analyzed.This review expectedly promotes and inspires the emergence of natural raw collagen-based materials as an advanced substitute biomaterial to autologous tissue transplantation.