Adhesion properties of catechol functionalized poly-r-glutamic acid (r-PGA)

For a long period of time, sutures and staples were used as a mechanical binder. However, this mechanical binder may cause disadvantages such as surrounding tissue site damage, and low oxygen permeability etc. In addition, the... [ view full abstract ]

For a long period of time, sutures and staples were used as a mechanical binder. However, this mechanical binder may cause disadvantages such as surrounding tissue site damage, and low oxygen permeability etc. In addition, the accuracy is decreased when applied to the poor accessibility tissue site. Therefore, the tissue adhesive is challenging to develop a material that can replace the mechanical binder such as sutures and staples. Tissue adhesive is generally a substance that can be adhere the surface of the tissue and/or non-tissue and these materials have been widely studied due to their excellent advantage such as convenience, excellent hemostatic effect, and air leakage prevention effect, and reduced surgery time and bleeding. However, commercially used tissue adhesives have low adhesion strength in wet condition and cytotoxicity. Accordingly, it has become a big issue to develop a new high performance tissue adhesive which can be used in wet condition and various tissue sites. Poly-r-glutamic acid (r-PGA) is anionic, naturally occurring polyamide that is consist of D-and L-glutamic acid units linked by amide bond between a-amino and g-carboxylic acid groups. r-PGA is a microorganism metabolite produced by some Bacillus species such as licheniformis and subtilis. Another naturally occurring source of r-PGA is mucilage of natto (fermented soybean). With excellent biodegradability and biocompatibility, r-PGA and its derivatives have been widely used in the fields of drug delivery, wound dressing, and tissue engineering. Mussels are able to anchor to underwater surface by secreting an adhesive plaque composed of mussel adhesive proteins (MAPs). Especially, the catechol moiety in MAPs tethering to surfaces through formation of insoluble poly(DOPA) derivatives by cross-linking. Mussel-inspired adhesives are expected as biological adhesives for wet condition under the clinical environments. In this study, to improve the adhesive properties in wet condition and biocompatibility of tissue adhesives, functional catechol group was introduced into r-PGA, and the adhesive properties was evaluated.