Compressed collagen gel as the scaffold for skin engineering
Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, People's Republic of China. Biomedical Microdevices
(Impact Factor: 2.88).
03/2010; 12(4):627-35. DOI: 10.1007/s10544-010-9415-4
Collagen gel scaffolds can potentially be utilized as cell seeded systems for skin tissue engineering. However, its dramatic contraction after being mixed with cells and its mechanical weakness are the drawbacks for its application to skin engineering. In this study, a compressed collagen gel scaffold was fabricated through the rapid expulsion of liquid from reconstituted gels by the application of 'plastic compression'(PC) technique. Both compressed and uncompressed gels were characterized with their gel contraction rate, morphology, the viability of seeded cells, their mechanical properties and the feasibility as a scaffold for constructing tissue-engineered skin. The results showed that the compression could significantly reduce the contraction of the collagen gel and improve its mechanical property. In addition, seeded dermal fibroblasts survived well in the compressed gel and seeded epidermal cells gradually developed into a stratified epidermal layer, and thus formed tissue engineered skin. This study reveals the potential of using compressed collagen gel as a scaffold for skin engineering.
Available from: Laurent Bozec
- "After incubation in submerged conditions for 5 days and 16 days with an air–liquid interface, the compressed collagen construct presented a skin-like morphology. However, the strength property of this construct was not adequate enough for immediate implantation . It is clear from various researches conducted , that there is a need for mechanically stronger collagen constructs to be used as tissue engineering scaffolds. "
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ABSTRACT: The use of collagen scaffold in tissue engineering is on the rise, as modifications to mechanical properties are becoming more effective in strengthening constructs whilst preserving the natural biocompatibility. The combined technique of plastic compression and cross-linking is known to increase the mechanical strength of the collagen construct. Here, a modified protocol for engineering these collagen constructs is used to bring together a plastic compression method, combined with controlled photochemical crosslinking using riboflavin as a photoinitiator. In order to ascertain the effects of the photochemical crosslinking approach and the impact of the crosslinks created upon the properties of the engineered collagen constructs, the constructs were characterized both at the macroscale and at the fibrillar level. The resulting constructs were found to have a 2.5 fold increase in their Young's modulus, reaching a value of 650 ± 73 kPa when compared to non-crosslinked control collagen constructs. This value is not yet comparable to that of native tendon, but it proves that combining a crosslinking methodology to collagen tissue engineering may offer a new approach to create stronger, biomimetic constructs. A notable outcome of crosslinking collagen with riboflavin is the collagen's greater affinity for water; it was demonstrated that riboflavin crosslinked collagen retains water for a longer period of time compared to non-cross-linked control samples. The affinity of the cross-linked collagen to water also resulted in an increase of individual collagen fibrils' cross-sectional area as function of the crosslinking. These changes in water affinity and fibril morphology induced by the process of crosslinking could indicate that the crosslinked chains created during the photochemical crosslinking process may act as intermolecular hydrophilic nanosprings. These intermolecular nanosprings would be responsible for a change in the fibril morphology to accommodate variable volume of water within the fibril.
Available from: Ahad Khoshzaban
- "Polymers are biomaterials whose natural forms, because of their biocompatibility and biodegradability, are given more attention in comparison with synthetic biomaterials (Swetha et al. 2010; Gaspar et al. 2011; Xu et al. 2011). Collagen, which is the most abundant protein in human body (Hu et al. 2010), is known as a protein polymer in bone tissue engineering (Swetha et al. 2010), and can be acquired from various tissues like pericardium, tendon, and skin with different sources such as porcine, bovine, and human as a biomaterial for miscellaneous purposes (Park et al. 2008; Hunt and Grover 2010; Bela et al. 2010; Neulen et al. 2011). Collagen type I is the main component of pericardium fibrous layer (Spodick 1997; Jastrzebska et al. 2005; Munnelly et al. 2011). "
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ABSTRACT: Regaining adequate bone strength, in bone loss, is one of the main purposes for new bone regeneration in bone tissue engineering. Biomechanical hardness test can be one approach to assay bone consistency in new bone formation. In addition, following up the serum alkaline phosphatase (ALP) alterations may help us in order to evaluate bone formation activity. In the current research, two groups of five male white New Zealand rabbits were studied. Two defects, 8 mm in diameter each, were made in each rabbit calvarium, one defect was filled with either human pericardial collagen (HPM) or demineralized bone matrix (DBM), and the other one was left empty as control. Every 10 days post-surgery, the serum ALP level was assessed, for 60 days. After performing euthanasia on day 60, the specimens were sent for biomechanical hardness test. The results for the DBM containing group were better than the HPM containing group in both biomechanical and biochemical tests. However, they were not statistically significant (p > 0. 05). In the biomechanical test, all the experimental groups, in both DBM and HPM, had significantly more hardness than the control (p < 0. 05). DBM is a current and well-known graft used in bone regeneration. Since, there was no significant difference between HPM and DBM on one hand, and the superiority of the HPM experimental group in the biomechanical test to the control on the other hand, HPM might be considered as a suitable graft in bone repair leading to acceptable bone strength.
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ABSTRACT: A biodegradable hybrid scaffold consisting of a synthetic polymer, poly(lactic acid-co-caprolactone) (PLACL), and a naturally derived polymer, collagen, was constructed by plastic compressing hyperhydrated collagen gels onto a flat warp-knitted PLACL mesh. The collagen compaction process was characterized, and it was found that the duration, rather than the applied load under the test conditions in the plastic compression, was the determining factor of the collagen and cell density in the cell-carrying component. Cells were spatially distributed in three different setups and statically cultured for a period of 7 days. Short-term biocompatibility of the hybrid construct was quantitatively assessed with AlamarBlue and qualitatively with fluorescence staining and confocal microscopy. No significant cell death was observed after the plastic compression of the interstitial equivalents, confirming previous reports of good cell viability retention. The interstitial, epithelial, and composite tissue equivalents showed no macroscopic signs of contraction and good cell proliferation with a two- to threefold increase in cell number over 7 days. Quantitative analysis showed a homogenous cell distribution and good biocompatibility. The results indicate that viable and proliferating multilayered tissue equivalents can be engineered using the PLACL-collagen hybrid construct in the space of several hours.
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