PH-Triggered Adhesiveness and Cohesiveness of Chondroitin Sulfate-Catechol Biopolymer for Biomedical Applications.

Annachiara Scalzone,Ana M. Ferreira,Maria A. Bonifacio,Stefania Cometa,Piergiorgio Gentile,Elvira De Giglio,Fabio Cucinotta

doi:10.3389/fbioe.2020.00712

Abstract

Nature provides biomaterials that tend to be effective to control both their adhesive and cohesive properties. A catecholamine motif found in the marine mussels, the mytilus edulis foot protein, can play adhesiveness and cohesiveness. Particularly, acidic pH drives catechol (Cat) to have adhesive function, resulting in surface coating, while basic pH allows to enhance its cohesive properties, resulting in the formation of hydrogels. In this work, we demonstrated the usefulness of Cat-conjugated chondroitin sulfate (CS) as a platform for mesenchymal stem cell culture, utilizing the adhesive property of CS-Cat as coating for different substrates and the cohesive properties as hydrogel for cells encapsulation. To prepare the CS-Cat biopolymer, dopamine (DP) was coupled to the CS by carbodiimide coupling reaction and the Cat content was determined by UV–Vis spectroscopy (4.8 ± 0.6%). To demonstrate the adhesive properties of the biopolymer, PLA, PCL, TiO2, and SiO2 substrates were immersed in CS-Cat solution (pH < 2). Following the coating, the surfaces became highly hydrophilic, exhibiting a contact angle less than 35°. Also, in the presence of an oxidizing agent at pH 8, CS-Cat solution immediately became a hydrogel, as shown by inverted-vial test. Finally, immortalized TERT human mesenchymal stem cells (Y201) confirmed the high cytocompatibility of the biopolymer. The CS-Cat coating significantly enabled the Y201 adhesion onto PLA substrates, while the prepared hydrogel demonstrated to be a suitable environment for the encapsulation of cells as suitable bioink for further bioprinting applications.

Highlights

Adhesive and cohesive properties are crucial features for the synthesis of functionalised materials, in the biomedical field for different application, i.e., tissue engineering, cell therapy, microfluidics, etc
Adhesive means any attraction between different molecular species, brought into direct contact as the adhesive could stick or binds to the applied surface; while cohesive means attraction that occurs between similar pH-Triggered Chondroitin Sulfate-Catechol Biopolymer molecular species, as results of chemical bonds between the single components of the adhesive agents (Von Fraunhofer, 2012)
Considering the before mentioned requirements, various hydrogels-based bioadhesive systems have been exploited, with several inspired by marine mussels because of the adhesive strength of mussel foot proteins within a wet environment and the adaptable chemistry of catechol (Cat) groups

Summary

Introduction

Adhesive and cohesive properties are crucial features for the synthesis of functionalised materials, in the biomedical field for different application, i.e., tissue engineering, cell therapy, microfluidics, etc. Considering the before mentioned requirements, various hydrogels-based bioadhesive systems have been exploited, with several inspired by marine mussels because of the adhesive strength of mussel foot proteins within a wet environment and the adaptable chemistry of catechol (Cat) groups. There is a Cat amine motif found in the marine mussels, the mytilus edulis foot protein (3,4-dihydroxy-L-phenylalanine and lysine), able to play adhesiveness and cohesiveness, based on the pH (Waite and Tanzer, 1981; Lee et al, 2007). Acidic pH drives Cat to have an adhesive function, obtaining a surface coating, while basic pH allows to increase its cohesive properties, resulting in the formation of hydrogels (Ryu et al, 2015). In an alkaline environment, the formation of transient quinone groups leads to crosslinking reactions (e.g., dismutation and Cat–Cat bonds, hydrogen bonds, and van der Waals and other cohesive forces established with the polymeric chains), as previously reported (Yang J. et al, 2014)

Methods

Results

Conclusion