scholarly journals Biologically active collagen-based scaffolds: advances in processing and characterization

2010 ◽  
Vol 368 (1917) ◽  
pp. 2123-2139 ◽  
Author(s):  
I. V. Yannas ◽  
D. S. Tzeranis ◽  
B. A. Harley ◽  
P. T. C. So
Keyword(s):  
Biological Activity ◽  
Pore Size ◽  
Type I Collagen ◽  
Biologically Active ◽  
Wound Contraction ◽  
Type I ◽  
Structural Determinants ◽  
Ligand Density ◽  
Freeze Dried ◽  
Recent Developments

A small number of type I collagen–glycosaminoglycan scaffolds (collagen–GAG scaffolds; CGSs) have unusual biological activity consisting primarily in inducing partial regeneration of organs in the adult mammal. Two of these are currently in use in a variety of clinical settings. CGSs appear to induce regeneration by blocking the adult healing response, following trauma, consisting of wound contraction and scar formation. Several structural determinants of biological activity have been identified, including ligands for binding of fibroblasts to the collagen surface, the mean pore size (which affects ligand density) and the degradation rate (which affects the duration of the wound contraction-blocking activity by the scaffold). Processing variables that affect these determinants include the kinetics of swelling of collagen fibres in acetic acid, freezing of the collagen–GAG suspension and cross-linking of the freeze-dried scaffold. Recent developments in the processing of CGSs include fabrication of scaffolds that are paucidisperse in pore size, scaffolds with gradients in physicochemical properties (and therefore biological activity) and scaffolds that incorporate a mineral component. Advances in the characterization of the pore structure of CGSs have been made using confocal and nonlinear optical microscopy (NLOM). The mechanical behaviour of CGSs, as well as the resistance to degradative enzymes, have been studied. Following seeding with cells (typically fibroblasts), contractile forces in the range 26–450 nN per cell are generated by the cells, leading to buckling of scaffold struts. Ongoing studies of cell-seeded CGSs with NLOM have shown an advantage over the use of confocal microscopy due to the ability of the former method to image the CGS surfaces without staining (which alters its surface ligands), reduced cell photodamage, reduced fluorophore photobleaching and the ability to image deeper inside the scaffold.

scholarly journals DIFFERENCES OF BONE REGENERATION USING BOVINE HYDROXYAPATITE AND BOVINE HYDROXYAPATITE WITH FREEZE-DRIED PLATELET RICH PLASMA ALLOGRAFT IN BONE DEFECT OF FEMORAL WHITE RABBIT

2020 ◽  
Vol 9 (2) ◽  
pp. 34
Author(s):  
Mouli Edward ◽  
Henry Dominica ◽  
Ferdiansyah Mahyudin ◽  
Fedik Abdul Rantam
Keyword(s):  
Alkaline Phosphatase ◽  
Treatment Group ◽  
Type I Collagen ◽  
Platelet Rich Plasma ◽  
Bone Defects ◽  
Type I ◽  
The Third ◽  
Woven Bone ◽  
Freeze Dried ◽  
Bovine Hydroxyapatite

Background: Bone defects to date have been a significant problem in the Orthopedics field. Hydroxyapatite is a bone graft that is often chosen if it has osteoconductive properties. Platelet-rich plasma (PRP) has a higher platelet concentration than the concentration in normal blood, capable of providing many bioactive molecules in physiological proportions. Hydroxyapatite given freeze-dried PRP is expected to create a graft that can strengthen the matrix while promoting osteoinduction.Methods: This study compares the effects of regeneration on the bone between bovine hydroxyapatite (BHA) and bovine hydroxyapatite with freeze-dried platelet-rich plasma (FD-PRP) as a bone graft in bone defect of the femoral white rabbit. The 12 equal New Zealand white rabbits aged 6-9 months are divided into two groups. Bone defects were made in the lower femoral meta-diaphysis with a diameter of 2.5 mm. The defects were filled with BHA with FD-PRP allograft in the treatment group and BHA in the control group. Both groups will be sacrificed in the third and sixth weeks, then evaluated histologically for microvascular structure, osteoblasts, woven bone, type-I collagen, osteocalcin, alkaline phosphatase, and immunoglobulin G.Results: During the evaluation in week 3 and 6, microvascular structure, osteoblast, and type-I collagen decreased in both groups with insignificant differences (p>0.05). Woven bone, osteocalcin, and immunoglobulin G increased in the treatment group but was not significant (p>0.05). Alkaline phosphatase increased higher in the treatment group, with a considerable difference in the sixth week (p=0.008).Conclusion: The elevation in the production of woven bone, osteocalcin, and alkaline phosphatase at the third and sixth-week evaluations highlight the possibility that administering BHA given FD-PRP may have contributed to the healing of bone defects.

Stability of the Magnesium Carbonate Apatite/Anionic Collagen Scaffolds: Effect of the Cross-Link Concentration

2011 ◽  
Vol 493-494 ◽  
pp. 844-848 ◽  
Author(s):  
Marcia S. Sader ◽  
Gutemberg Alves ◽  
Racquel Z. LeGeros ◽  
Gloria Dulce de Almeida Soares
Keyword(s):  
Bone Tissue ◽  
Culture Medium ◽  
Type I Collagen ◽  
Type I ◽  
Carbonate Apatite ◽  
Reaction Products ◽  
Collagen Scaffolds ◽  
Freeze Dried ◽  
The Cross

Natural bone constitutes of an inorganic phase (a biological nanoapatite) and an organic phase (mostly type I collagen). The challenge is to develop a material that can regenerate lost bone tissue with degradation and resorption kinetics compatible with the new bone formation. The aim of this study was to prepare self-organized magnesium and carbonate substituted apatite/collagen scaffolds, cross-linked with glutaraldehyde (GA). Bovine tendon was submitted to alkaline treatment resulting in a negatively charged collagen surface. The scaffolds were prepared by precipitation: simultaneous dropwise addition of solution containing calcium (Ca) and magnesium (Mg) ions and collagen into a buffered solution containing carbonate and phosphate ions in reaction vessel maintained at 37 °C, pH=8. The reaction products were cross-linked with 0.125 and 0.25% (v/v) glutaraldehyde (GA) solution and freeze-dried. The samples were characterized by Fourier-transformed infrared spectroscopy (FTIR). In vitro cytotoxicity (based on three parameters assays) and scaffolds degradation in culture medium and osteoblastic cells culture were performed in the cross-linked materials. No cytotoxic effects were observed. The cross-linked samples with the lower GA concentration showed a lower stability when placed in contact with culture medium. Human osteoblasts attached on the scaffolds surface cross-linked with 0.25% GA, forming a continuous layer after 14 days of incubation. These results showed potential application of the designed scaffolds for bone tissue engineering.

Freeze-Dried, Cross-Linked Bovine Type I Collagen: Analysis of Properties

1992 ◽  
Vol 63 (3) ◽  
pp. 182-186 ◽  
Author(s):  
P. R. Hyder ◽  
P. Dowell ◽  
G. Singh ◽  
A. E. Dolby
Keyword(s):  
Type I Collagen ◽  
Type I ◽  
Freeze Dried ◽  
Collagen Analysis ◽  
Bovine Type

scholarly journals A thermoreversible, photocrosslinkable collagen bio-ink for free-form fabrication of scaffolds for regenerative medicine

TECHNOLOGY ◽  
2017 ◽  
Vol 05 (04) ◽  
pp. 185-195 ◽  
Author(s):  
Kathryn E. Drzewiecki ◽  
Juilee N. Malavade ◽  
Ijaz Ahmed ◽  
Christopher J. Lowe ◽  
David I. Shreiber
Keyword(s):  
Tissue Engineering ◽  
Regenerative Medicine ◽  
Self Assembly ◽  
Type I Collagen ◽  
The Body ◽  
Free Form ◽  
Type I ◽  
Freeze Dried ◽  
Good Pattern ◽  
Further Development

As a biomaterial, collagen has been used throughout tissue engineering and regenerative medicine. Collagen is native to the body, is highly biocompatible, and naturally promotes cell adhesion and regeneration. However, collagen fibers and the inherent weak mechanical properties of collagen hydrogels interfere with further development of collagen as a bio-ink. Herein, we demonstrate the use of a modified type-I collagen, collagen methacrylamide (CMA), as a fibril-forming bio-ink for free-form fabrication of scaffolds. Like collagen, CMA can self-assemble into a fibrillar hydrogel at physiological conditions. In contrast, CMA is photocrosslinkable and thermoreversible, and photocrosslinking eliminates thermoreversibility. Free-form fabrication of CMA was performed through self-assembly of the CMA hydrogel, photocrosslinking the structure of interest using a photomask, and cooling the entire hydrogel, which results in cold-melting of unphotocrosslinked regions. Printed hydrogels had a resolution on the order of [Formula: see text]350[Formula: see text][Formula: see text]m, and can be fabricated with or without cells and maintain viability or be further processed into freeze-dried sponges, all while retaining pattern fidelity. A subcutaneous implant study confirmed the biocompatibility of CMA in comparison to collagen. Free-form fabrication of CMA allows for printing of macroscale, customized scaffolds with good pattern fidelity and can be implemented with relative ease for continued research and development of collagen-based scaffolds in tissue engineering.

Pore size variable type I collagen gels and their interaction with glioma cells

Biomaterials ◽  
2010 ◽  
Vol 31 (21) ◽  
pp. 5678-5688 ◽  
Author(s):  
Ya-li Yang ◽  
Stéphanie Motte ◽  
Laura J. Kaufman
Keyword(s):  
Pore Size ◽  
Type I Collagen ◽  
Glioma Cells ◽  
Type I ◽  
Collagen Gels ◽  
Variable Type ◽  
Size Variable

scholarly journals Cardiac myofibroblasts isolated from the site of myocardial infarction express endothelin de novo

2003 ◽  
Vol 285 (3) ◽  
pp. H1132-H1139 ◽  
Author(s):  
Laxmansa C. Katwa
Keyword(s):  
Myocardial Infarction ◽  
Tissue Repair ◽  
Type I Collagen ◽  
Cultured Cells ◽  
De Novo ◽  
Culture Media ◽  
Myocardial Infarct ◽  
Biologically Active ◽  
Myocardial Infarct Size ◽  
Type I

Recently it was demonstrated that treatment with a nonselective endothelin (ET) receptor antagonist significantly reduces myocardial infarct size, which suggests a major role for ET in tissue repair following myocardial infarction (MI). Tissue repair and remodeling found at the site of MI are mainly attributed to myofibroblasts (myoFbs), which are phenotypically transformed fibroblasts that express α-smooth muscle actin. It is unclear whether myoFbs generate ET peptides and consequentially regulate pathophysiological functions de novo through expression of the ET-1 precursor (prepro-ET-1), ET-converting enzyme-1 (ECE-1), a metalloprotease that is required to convert Big ET-1 to ET-1 and ET receptors. To address these intriguing questions, we used cultured myoFbs isolated from 4-wk-old MI scar tissue. In cultured cells, we found: 1) expression of mRNA for ET precursor gene ( ppET1), ECE-1, and ETA and ETB receptors by semiquantitative RT-PCR; 2) phosphoramidon-sensitive ECE-1 activity, which converts Big ET-1 to biologically active peptide ET-1; 3) expression of ETA and ETB receptors; 4) elaboration of Big ET-1 and ET-1 peptides in myoFb culture media; and 5) upregulation of type I collagen gene expression and synthesis by ET, which was blocked by bosentan (a nonselective ETA- and ETB receptor blocker). These studies clearly indicated that myoFbs express and generate ET-1 and receptor-mediated modulation of type I collagen expression by ET-1. Locally generated ET-1 may contribute to tissue repair of the infarcted heart in an autocrine/paracrine manner.

A Collagen/DBP Sponge System Designed for in Vitro Analysis of Chondroinduction

1991 ◽  
Vol 252 ◽  
Author(s):  
Shuichi Mizuno ◽  
Chris Lycette ◽  
Charlene Quinto ◽  
Julie Glowacki
Keyword(s):  
Type I Collagen ◽  
Three Dimensional ◽  
Dermal Fibroblasts ◽  
Type I ◽  
Cellular Mechanisms ◽  
Fresh Tissue ◽  
Freeze Dried ◽  
Bone Powder

ABSTRACTIn response to subcutaneous implants of demineralized bone powder (DBP), cells are attracted to the DBP, are converted to chondroblasts, and produce a cartilage matrix that is resorbed and replaced by bone. In order to define the cellular mechanisms of this induction, we developed a collagen sponge model for simulating the in vivo environment and for promoting the ingrowth and viability of cells cultured in them in vitro. Reconstituted pepsin–digested type I collagen from bovine hide was neutralized. Rat DBP (75–250 εm) was added into the collagen mixture (20 mg/ml). In order to simulate the connective tissue environment, modified chondroitin sulfate, heparan sulfate, or hyaluronic acid was added into the mixture. Aliquots (0.2 ml) were placed in 3/8 inch diameter molds and freeze-dried. Human dermal fibroblasts were cultured from minced fresh tissue and inoculated at 1.5 × 105 cells/sponge. Fifteen hours later, some sponges were transferred to medium which contained growth factors (PDGF or TGF-β). At intervals, samples were examined histologically. The inoculated cells attached to the collagen fibers and migrated into the sponge. Eventually the sponges contracted and acquired an oval shape. Cells on or near DBP were ovoid or stellate in shape. Cell morphology was modulated by glycosaminoglycan composition of the sponge. Increasing doses of PDGF or TGF-β promoted cellularity within the sponges. In conclusion, this system simulates the in vivo environment but allows accessibility for analysis. This three-dimensional matrix culture system will enable investigation of mechanisms of chondroinduction by morphogenic material.

scholarly journals Dualistic nature of adhesive protein function: fibronectin and its biologically active peptide fragments can autoinhibit fibronectin function.

1984 ◽  
Vol 99 (1) ◽  
pp. 29-36 ◽  
Author(s):  
K M Yamada ◽  
D W Kennedy
Keyword(s):  
Type I Collagen ◽  
Cell Attachment ◽  
Cell Spreading ◽  
Biologically Active ◽  
Cell Surface Receptor ◽  
Type I ◽  
Peptide Fragments ◽  
Adhesive Protein ◽  
Active Peptide ◽  
Biologically Active Peptide

Fibronectin and certain polypeptide regions of this adhesive glycoprotein mediate cell attachment and spreading on various substrates. We explored the theoretical prediction that this adhesive protein could become a competitive inhibitor of fibronectin-mediated processes if present in solution at appropriately high concentrations. Fibronectin function was inhibited by purified plasma fibronectin at 5-10 mg/ml, by a 75,000-dalton cell-interaction fragment of the protein at 0.5-1 mg/ml, and even by two synthetic peptides containing a conserved, hydrophilic amino acid sequence at 0.1-0.5 mg/ml. Inhibition of fibronectin-dependent cell spreading was dose dependent, noncytotoxic, and reversible. It was competitive in nature, since increased quantities of substrate-adsorbed fibronectin or longer incubation periods decreased the inhibition. A peptide inhibitory for fibronectin-mediated cell spreading also inhibited fibronectin-mediated attachment of cells to type I collagen, but it did not affect concanavalin A-mediated spreading. These results demonstrate the potential of a cell adhesion molecule and its biologically active peptide fragments to act as competitive inhibitors, and they suggest that fibronectin may act by binding to a saturable cell surface receptor.

scholarly journals Recent developments in osteogenesis imperfecta

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 681 ◽  
Author(s):  
Joseph L. Shaker ◽  
Carolyne Albert ◽  
Jessica Fritz ◽  
Gerald Harris
Keyword(s):  
Osteogenesis Imperfecta ◽  
Fall Prevention ◽  
Type I Collagen ◽  
Biomechanical Properties ◽  
Orthopedic Procedures ◽  
Type I ◽  
Fractures In Children ◽  
Recent Developments ◽  
Brittle Bones ◽  
Pharmacologic Therapies

Osteogenesis imperfecta (OI) is an uncommon genetic bone disease associated with brittle bones and fractures in children and adults. Although OI is most commonly associated with mutations of the genes for type I collagen, many other genes (some associated with type I collagen processing) have now been identified. The genetics of OI and advances in our understanding of the biomechanical properties of OI bone are reviewed in this article. Treatment includes physiotherapy, fall prevention, and sometimes orthopedic procedures. In this brief review, we will also discuss current understanding of pharmacologic therapies for treatment of OI.

scholarly journals A MECHANOCHEMICAL MODEL FOR ADULT DERMAL WOUND CONTRACTION

1995 ◽  
Vol 03 (04) ◽  
pp. 1021-1031 ◽  
Author(s):  
L. OLSEN ◽  
J. A. SHERRATT ◽  
P. K. MAINI
Keyword(s):  
Experimental Data ◽  
Cell Biology ◽  
Type I Collagen ◽  
Cell Types ◽  
Wound Contraction ◽  
Valuable Insight ◽  
Type I ◽  
The Matrix ◽  
Mechanochemical Model ◽  
Collagen Remodelling

We propose a deterministic mathematical model to describe the biomechanics and cell biology of wound contraction, a ubiquitous feature in the normal healing of adult dermal excisional wounds. Our aim is to use the model to obtain a greater understanding of the mechanisms involved in wound contraction and in clinically important healing pathologies such as fibrocontractive diseases. The model consists of two cell types — fibroblasts aand myofibroblasts, a generic chemical growth factor and a viscoelastic extracellular matrix (which includes type I collagen). The essential processes of cell motility, proliferation, differentiation and mechanical interaction with the matrix are modelled from experimental data. A novel aspect of this approach is the inclusion of two cell types. The model is shown not only to simulate normal wound contraction (in good agreement with experimental data), but also to yield valuable insight into the fundamental mechanisms involved and the pathogenesis of fibrocontractive diseases, and makes experimentally testable predictions of the effects of varying biological parameters. Two important results are that collagen remodelling is more intrinsic to scar formation than to wound contraction and that dynamic gradients in the cell and matrix densities are the driving force for wound contraction.

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