Interfacial reinforcement in bioceramic/biopolymer composite bone scaffold: The role of coupling agent

The combination of biopolymer and bioceramic can mimic the chemical composition of the native bone extracellular matrix which is composed of inorganic minerals and organic collagenous. However, the poor interfacial compatibility between organic biopolymer and inorganic bioceramic restricts the full development of bioceramic/biopolymer composite scaffold for bone regeneration application. Coupling agents have been widely used to build a molecular bridge in the interface between biopolymer and bioceramic due to the two different functional groups in its structure. One is organophilic functional groups which can react with polymer molecules, and the other is special functional groups which can adsorb on bioceramic surface to form a firm bond. As a result, the stress transfer efficiency between biopolymer and bioceramic can be enhanced, and thereby improving the mechanical properties of the composite scaffold. In this study, the interfacial features between bioceramic and biopolymer and the methods to improve interface bonding were presented, and the interfacial reaction mechanisms under the action of coupling agents especially silane coupling agents were focused on discussing. In addition, the mechanical properties, in vitro and in vivo biological properties of the bioceramic/biopolymer composite scaffold after coupling agent modification were systematically summarized. Finally, suggestions for further work were put forward, including the study on controlling coupling agent content, and more in vitro and in vivo experimental evaluation.