title: Thermogelling chitosan-collagen-bioactive glass nanoparticle hybrids as potential injectable systems for tissue engineering.
abstract: Recently, stimuli-responsive nanocomposite-derived hydrogels have gained prominence in tissue engineering because they can be applied as injectable scaffolds in bone and cartilage repair. Due to the great potential of these systems, this study aimed to synthesize and characterize novel thermosensitive chitosan-based composites, chemically modified with collagen and reinforced by bioactive glass nanoparticles (BG) on the development of injectable nanohybrids for regenerative medicine applications. Thus, the composite hydrogels were extensively characterized by structural, morphological, rheological, and biological testing. The composites showed thermosensitive response with the gelation temperature at approximately 37 °C, which is compatible with the human body temperature. In addition, scanning electron microscopy (SEM) analysis indicated that the chitosan hydrogels exhibited 3D-porous structures, and the incorporation of collagen in the system caused increase on the average pore size. Fourier transform infrared spectroscopy (FTIR) analysis indicated the main functional groups of each component of the composite system and their chemical interactions forming the scaffold. Moreover, rheological measurements were employed to assess the viscoelastic behavior of the hydrogels as a function of the temperature. The results demonstrated that the addition of collagen and bioactive glass increases the mechanical properties after the gelation process. The addition of 2 wt.% of BG nanoparticles caused an increase of approximately 39% on stiffness compared to pure chitosan and the addition of 30 wt.% collagen caused a further increase on the stiffness by 95%. The cytotoxicity and cell viability of the hydrogels were assessed by MTT and LIVE/DEAD® assays, where the results demonstrated no toxic effect of the composites on the human osteosarcoma cell culture (SAOS) and kidney cells line of human embryo (HEK 293 T). Hence, it can be stated that innovative composites were successfully designed and synthesized in this research with promising potential to be used as thermoresponsive biomaterials for bone-tissue bioapplications.
authors.affiliation: Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Escola de Engenharia, Bloco 2, Sala 2233, 31.270-901, Belo Horizonte/MG, Brazil.
authors.forename: Cheisy D F
authors.initials: CD
authors.lastname: Moreira
authors.affiliation: Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Escola de Engenharia, Bloco 2, Sala 2233, 31.270-901, Belo Horizonte/MG, Brazil.
authors.forename: Sandhra M
authors.initials: SM
authors.lastname: Carvalho
authors.affiliation: Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Escola de Engenharia, Bloco 2, Sala 2233, 31.270-901, Belo Horizonte/MG, Brazil. Electronic address: hmansur@demet.ufmg.br.
authors.forename: Herman S
authors.initials: HS
authors.lastname: Mansur
authors.affiliation: Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Escola de Engenharia, Bloco 2, Sala 2233, 31.270-901, Belo Horizonte/MG, Brazil. Electronic address: mpereira@demet.ufmg.br.
authors.forename: Marivalda M
authors.initials: MM
authors.lastname: Pereira
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D057809:HEK293 Cells; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D003094:Collagen; D048271:Chitosan
keywords: Biocomposite; Biomaterial; Collagen; Composite; Scaffolds; Thermosensitive hydrogels