title: Fabrication and evaluation of a sustained-release chitosan-based scaffold embedded with PLGA microspheres.
abstract: Nutrient depletion within three-dimensional (3D) scaffolds is one of the major hurdles in the use of this technology to grow cells for applications in tissue engineering. In order to help in addressing it, we herein propose to use the controlled release of encapsulated nutrients within polymer microspheres into chitosan-based 3D scaffolds, wherein the microspheres are embedded. This method has allowed maintaining a stable concentration of nutrients within the scaffolds over the long term. The polymer microspheres were prepared using multiple emulsions (w/o/w), in which bovine serum albumin (BSA) and poly (lactic-co-glycolic) acid (PLGA) were regarded as the protein pattern and the exoperidium material, respectively. These were then mixed with a chitosan solution in order to form the scaffolds by cryo-desiccation. The release of BSA, entrapped within the embedded microspheres, was monitored with time using a BCA kit. The morphology and structure of the PLGA microspheres containing BSA before and after embedding within the scaffold were observed under a scanning electron microscope (SEM). These had a round shape with diameters in the range of 27-55 μm, whereas the chitosan-based scaffolds had a uniform porous structure with the microspheres uniformly dispersed within their 3D structure and without any morphological change. In addition, the porosity, water absorption and degradation rate at 37 °C in an aqueous environment of 1% chitosan-based scaffolds were (92.99±2.51) %, (89.66±0.66) % and (73.77±3.21) %, respectively. The studies of BSA release from the embedded microspheres have shown a sustained and cumulative tendency with little initial burst, with (20.24±0.83) % of the initial amount released after 168 h (an average rate of 0.12%/h). The protein concentration within the chitosan-based scaffolds after 168 h was found to be (11.44±1.81)×10(-2) mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a promising technique for the development of new and improved tissue engineering scaffolds.
authors.affiliation: Dalian R&D Center for Stem Cell and Tissue Engineering, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China. kedongsong@dlut.edu.cn
authors.forename: Kedong
authors.initials: K
authors.lastname: Song
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Liu
authors.forename: Hugo M
authors.initials: HM
authors.lastname: Macedo
authors.forename: Lili
authors.initials: L
authors.lastname: Jiang
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.forename: Guanyu
authors.initials: G
authors.lastname: Mei
authors.forename: Tianqing
authors.initials: T
authors.lastname: Liu
mesh_terms: D000818:Animals; D002417:Cattle; D048271:Chitosan / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004058:Diffusion; D016503:Drug Delivery Systems / Q000379:methods*; D019344:Lactic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D058953:Neural Stem Cells / Q000166:cytology; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity; D012710:Serum Albumin, Bovine / Q000032:analysis; D054457:Tissue Scaffolds / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D012710:Serum Albumin, Bovine; D019344:Lactic Acid; D048271:Chitosan
keywords: BSA; Chitosan-based 3D scaffold; Drug release; Microsphere; PLGA