title: Polymeric cryogels are biocompatible, and their biodegradation is independent of oxidative radicals.
abstract: Biocompatibility and in vivo degradation are two important characteristics of cell scaffolds. We evaluated these properties for four different polymeric macroporous cryogels, polyvinylcaprolactam, polyvinyl alcohol-alginate-bioactive glass composite, polyhydroxyethylmethacrylate-gelatin (pHEMA-gelatin), and chitosan-agarose-gelatin in mice. All the cryogels were synthesized at subzero temperature and were implanted subcutaneously in C57Bl/10.Q inbred mice. Both local and systemic toxicities were negligible as determined by serum tumor necrosis factor α analysis and histology of surrounding tissues nearby the implants. Complete integration of cryogels into the surrounding tissues with neovascular formation was evident in all the mice. At the implantation site, massive infiltration of macrophages and few dendritic cells were observed but neutrophils and mast cells were clearly absent. Macrophage infiltrations were observed even inside the pores of cryogel implants. To ascertain whether oxidative radicals are involved in the cryogel degradation, we implanted these gels in mice deficient for reactive oxygen species (ROS) production. Rapid gel degradation was observed in the absence of ROS, and there was no significant difference in the biodegradation of these cryogels between ROS sufficient and deficient mice thereby excluding any major role for ROS in this process. Thus, we demonstrate the biocompatibility and ROS-independent biodegradable properties of cryogels that could be useful for tissue-specific tissue engineering applications.
authors.affiliation: Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India; Department of Biochemistry and Biophysics, Medical Inflammation Research, Karolinska Institute, Stockholm, 17177, Sweden.
authors.forename: Akhilesh Kumar
authors.initials: AK
authors.lastname: Shakya
authors.forename: Rikard
authors.initials: R
authors.lastname: Holmdahl
authors.forename: Kutty Selva
authors.initials: KS
authors.lastname: Nandakumar
authors.forename: Ashok
authors.initials: A
authors.lastname: Kumar
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D059985:Cryogels / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D007150:Immunohistochemistry; D020007:Implants, Experimental; D007700:Kinetics; D008264:Macrophages / Q000166:cytology / Q000187:drug effects; D051379:Mice; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D059985:Cryogels; D011108:Polymers; D017382:Reactive Oxygen Species
keywords: biocompatibility; cryogel; degradation; host tissue response; toxicity