title: Injectable 3D hydrogel scaffold with tailorable porosity post-implantation.
abstract: Since rates of tissue growth vary significantly between tissue types, and also between individuals due to differences in age, dietary intake, and lifestyle-related factors, engineering a scaffold system that is appropriate for personalized tissue engineering remains a significant challenge. In this study, a gelatin-hydroxyphenylpropionic acid/carboxylmethylcellulose-tyramine (Gtn-HPA/CMC-Tyr) porous hydrogel system that allows the pore structure of scaffolds to be altered in vivo after implantation is developed. Cross-linking of Gtn-HPA/CMC-Tyr hydrogels via horseradish peroxidase oxidative coupling is examined both in vitro and in vivo. Post-implantation, further alteration of the hydrogel structure is achieved by injecting cellulase enzyme to digest the CMC component of the scaffold; this treatment yields a structure with larger pores and higher porosity than hydrogels without cellulase injection. Using this approach, the pore sizes of scaffolds are altered in vivo from 32-87 μm to 74-181 μm in a user-controled manner. The hydrogel is biocompatible to COS-7 cells and has mechanical properties similar to those of soft tissues. The new hydrogel system developed in this work provides clinicians with the ability to tailor the structure of scaffolds post-implantation depending on the growth rate of a tissue or an individual's recovery rate, and could thus be ideal for personalized tissue engineering.
authors.affiliation: Department of Chemical Engineering, Monash University, Clayton, 3800, Australia.
authors.forename: Aswan
authors.initials: A
authors.lastname: Al-Abboodi
authors.forename: Jing
authors.initials: J
authors.lastname: Fu
authors.forename: Pauline M
authors.initials: PM
authors.lastname: Doran
authors.forename: Timothy T Y
authors.initials: TT
authors.lastname: Tan
authors.forename: Peggy P Y
authors.initials: PP
authors.lastname: Chan
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000633:toxicity; D019556:COS Cells; D002266:Carboxymethylcellulose Sodium; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002480:Cellulase; D002522:Chlorocebus aethiops; D005260:Female; D005780:Gelatin; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000008:administration & dosage* / Q000737:chemistry* / Q000633:toxicity; D010666:Phenylpropionates; D016062:Porosity; D051381:Rats; D012212:Rheology; D054457:Tissue Scaffolds / Q000737:chemistry*; D014439:Tyramine
chemical_list: D001672:Biocompatible Materials; D010666:Phenylpropionates; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D005780:Gelatin; D002480:Cellulase; D002266:Carboxymethylcellulose Sodium; D014439:Tyramine
keywords: in vivo implantation; injectable hydrogels; porous scaffolds; tissue engineering; tunable porosity