Phase-separated chitosan–fibrin microbeads for cell delivery

Abstract

Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan–fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275 ± 99 μm to 38 ± 10 μm using impeller speeds from 600 to 1400 rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications.

Microcapsules engineered to support mesenchymal stem cell (MSC) survival and proliferation enable long-term retention of MSCs in infarcted myocardium

“…Similar proliferation rates have been observed with a collagen matrix [51]. In addition, proliferation of MSCs in microcapsules has generally not been observed in earlier approaches [31,45]. Transplanted MSCs perform all functions that are reported to contribute to tissue repair, as they are able to differentiate into other lineages and secrete paracrine factors.…”

“…All components are critical for the optimal performance of the microcapsule supporting proliferation and long-term survival of MSCs. Although materials such as agarose (or substituted by alginate) in combination with collagen [44], fibrin and fibronectin [30,31,45] have been investigated before, the resulting microcapsule biomaterials in earlier studies had limited performance. Most encapsulated cells (MSCs or fibroblasts) had a decreased viability over time.…”

“…Fibrin is an early matrix component produced during wound healing, is pro-angiogenic and provides further wound-healing signals to the encapsulated cells [29]. Supplementation of ECM proteins into hydrogel microcapsules has shown to improve the overall cell survival; however, a decrease in cell viability was still observed over time in these studies [30,31].…”

Comparison of Uncultured Marrow Mononuclear Cells and Culture-Expanded Mesenchymal Stem Cells in 3D Collagen-Chitosan Microbeads for Orthopedic Tissue Engineering

“…The 3D microbead matrix surrounding the cells contributes to cell viability maintenance, and the composition of the matrix can be tailored to promote cell adhesion, proliferation, and/or desired differentiation. [35][36][37] A main advantage of the microbead format is that cells (either freshly isolated or culture-expanded) can be directly embedded in microbeads, and they can then be cultured in suspension in the desired medium type until needed for delivery. Importantly, the microbeads can then be collected without trypsinization of the cells, and can be injected as a paste in a minimally invasive manner.…”

Fibrinogen and fibrin based micro and nano scaffolds incorporated with drugs, proteins, cells and genes for therapeutic biomedical applications

“…87 Recently, a Fbn-chitosan composite loaded with human fibroblasts showed good cells spreading effect and ECM interaction. 88 Both Fbnand collagen-based vascular grafts could be used as substitutes for bypass grafts or as models for vascular studies. 89 Very recently, Zhou et al successfully demonstrated the controlled delivery of recombinant human epidermal growth factor (rhEGF) using a Fbn-chitosan composite -the composite achieved a high protein loading efficacy due to the presence of chitosan and a lower initial burst release due to the Fbn.…”