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Kim H, Choi KH, Sung SC, Kim YS. Effect of ethanol washing on porcine pulmonary artery wall decellularization using sodium dodecyl sulfate. Artif Organs 2022; 46:1281-1293. [PMID: 35107179 DOI: 10.1111/aor.14192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/19/2021] [Accepted: 01/24/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND To determine the effectiveness of ethanol (EtOH) washing on porcine pulmonary artery (PA) wall decellularization using sodium dodecyl sulfate (SDS), we compared three different washing methods (phosphate-buffered saline [PBS], pH 9 alkali, and EtOH washing). METHODS Fresh porcine PA walls were decellularized using 0.5% SDS and 0.5% sodium deoxycholate (SDC). The decellularized tissues were rinsed using three different washing techniques. Histological, biochemical, and mechanical analyses were conducted. Implantation into the subcutaneous tissue of rats and patch implantation into the carotid artery of dogs were performed as preliminary in vivo studies. RESULTS The decellularization protocol based on SDS and SDC effectively removed the cells. The major extracellular matrix (ECM) structures (collagen, elastic fiber, and glycosaminoglycan) were properly preserved with the 75% EtOH-washing method. Significantly reduced residual SDS content was identified in EtOH-washed tissues compared to that in the other methods. No significant difference in the mechanical strength test was observed between the washing methods, and the EtOH-washing method showed better results in the metabolic activity test compared to the PBS-washing method. In the rat study model, no acute rejection or massive calcification was observed. The in vivo preliminary canine study showed better cell repopulation in the EtOH-washed group. CONCLUSION EtOH washing of SDS-based decellularized porcine PA wall can reduce the residual SDS content and preserve ECM structures, especially the elastin content, and could also enhance cell repopulation after re-implantation.
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Affiliation(s)
- Hyungtae Kim
- Department of Thoracic and Cardiovascular Surgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Kwang Ho Choi
- Department of Thoracic and Cardiovascular Surgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Si Chan Sung
- Department of Thoracic and Cardiovascular Surgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Young Suk Kim
- Department of Thoracic and Cardiovascular Surgery, Pusan National University Yangsan Hospital, Biomedical Research Institute, Yangsan, Korea
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2
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Łabuś W, Glik J, Klama-Baryła A, Kitala D, Kraut M, Maj M, Nowak M, Misiuga M, Marcinkowski A, Trzebicka B, Poloczek R, Kawecki M. Atomic force microscopy in the production of a biovital skin graft based on human acellular dermal matrix produced in-house and in vitro cultured human fibroblasts. J Biomed Mater Res B Appl Biomater 2017; 106:726-733. [PMID: 28323389 DOI: 10.1002/jbm.b.33883] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 02/08/2017] [Accepted: 02/28/2017] [Indexed: 12/18/2022]
Abstract
The most efficient method in III° burn treatment is the use of the autologous split thickness skin grafts that were donated from undamaged body area. The main limitation of this method is lack of suitable donor sites. Tissue engineering is a useful tool to solve this problem. The goal of this study was to find the most efficient way of producing biovital skin substitute based on in house produced acellular dermal matrix ADM and in vitro cultured fibroblasts. Sixty samples of sterilized human allogeneic skin (that came from 10 different donors) were used to examine the influence of decellularizing substances on extracellular matrix and clinical usefulness of the test samples of allogeneic human dermis. Six groups of acellular dermal matrix were studied: ADM-1 control group, ADM-2 research group (24 h incubation in 0.05% trypsin/EDTA solution), ADM-3 research group (24 h incubation in 0.025% trypsin/EDTA solution), ADM-4 research group (24 h incubation in 0.05% trypsin/EDTA solution and 4 h incubation in 0,1% SDS), ADM-5 research group (24 h incubation in 0.025% trypsin/EDTA solution and 4 h incubation in 0,1% SDS), and ADM-6 research group (24 h incubation in 0,1% SDS). Obtained ADMs were examined histochemically and by atomic force microscopy (AFM). ADMs were settled by human fibroblasts. The number of cultured cells and their vitality were measured. The obtained results indicated that the optimal method for production of living skin substitutes is colonization of autologous fibroblasts on the scaffold prepared by the incubation of human allogeneic dermis in 0.05% trypsin/EDTA. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 726-733, 2018.
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Affiliation(s)
- Wojciech Łabuś
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland
| | - Justyna Glik
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland.,Department of Chronic Wounds Management Organization, School of Health Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | | | - Diana Kitala
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland
| | - Małgorzata Kraut
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland
| | - Mariusz Maj
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland
| | - Mariusz Nowak
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland
| | - Marcelina Misiuga
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland
| | - Andrzej Marcinkowski
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Skłodowskiej 34 Str., 41-819, Zabrze, Poland
| | - Barbara Trzebicka
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Skłodowskiej 34 Str., 41-819, Zabrze, Poland
| | - Ryszard Poloczek
- Laboratory for Microscopic Examination "Diagno-Med", Siemianowice Slaskie, Poland
| | - Marek Kawecki
- Dr Stanislaw Sakiel Centre for Burn Treatment, Siemianowice, Śląskie, Poland.,The Department of Health Sciences, Technical-Humanistic Academy, 43-309, Bielsko-Biała, Poland
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3
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Taraballi F, Russo L, Battocchio C, Polzonetti G, Nicotra F, Cipolla L. A model study for tethering of (bio)active molecules to biomaterial surfaces through arginine. Org Biomol Chem 2016; 12:4089-92. [PMID: 24838600 DOI: 10.1039/c4ob00160e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A new approach for tethering of bioactive molecules via arginine is proposed and validated on collagen 2D matrices. The method involves the introduction of a methyl ketone on arginine side-chains, followed by reaction with model alkoxyamino derivatives.
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Affiliation(s)
- F Taraballi
- Pain Therapy Service, Fondazione IRCCS Policlinico San Matteo, via Golgi, 19-27100 Pavia, Italy
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4
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Barhoumi A, Salvador-Culla B, Kohane DS. NIR-triggered drug delivery by collagen-mediated second harmonic generation. Adv Healthc Mater 2015; 4:1159-63. [PMID: 25728310 DOI: 10.1002/adhm.201400768] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/30/2015] [Indexed: 11/08/2022]
Abstract
Second harmonic generation is a process through which nonlinear materials such as collagen can absorb two photons and scatter one with twice the energy. Collagen upconverts 730 nm (near-IR) to 365 nm (UV) through second harmonic generation, which cleaves a molecule bound to collagen via a UV-sensitive linker.
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Affiliation(s)
- Aoune Barhoumi
- Department of Anesthesiology; Division of Critical Care Medicine; Boston Children's Hospital; Harvard Medical School; 300 Longwood Avenue Boston MA 02115 USA
- David H. Koch Institute for Integrative Cancer Research; Massachusetts Institute of Technology; 77 Massachusetts Avenue Cambridge MA 02139 USA
| | - Borja Salvador-Culla
- Department of Anesthesiology; Division of Critical Care Medicine; Boston Children's Hospital; Harvard Medical School; 300 Longwood Avenue Boston MA 02115 USA
- David H. Koch Institute for Integrative Cancer Research; Massachusetts Institute of Technology; 77 Massachusetts Avenue Cambridge MA 02139 USA
- Department of Ophthalmology; Massachusetts Eye and Ear Infirmary; Harvard Medical School; 243 Charles street Boston MA 02114 USA
| | - Daniel S. Kohane
- Department of Anesthesiology; Division of Critical Care Medicine; Boston Children's Hospital; Harvard Medical School; 300 Longwood Avenue Boston MA 02115 USA
- David H. Koch Institute for Integrative Cancer Research; Massachusetts Institute of Technology; 77 Massachusetts Avenue Cambridge MA 02139 USA
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5
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Miguel FB, Barbosa Júnior ADA, de Paula FL, Barreto IC, Goissis G, Rosa FP. Regeneration of critical bone defects with anionic collagen matrix as scaffolds. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2013; 24:2567-2575. [PMID: 23784007 DOI: 10.1007/s10856-013-4980-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 06/10/2013] [Indexed: 06/02/2023]
Abstract
The aim of this study was to make a histomorphometric evaluation of the osteogenic potential of anionic collagen matrix as scaffolds; either crosslinked in glutaraldehyde or not cross-linked and, implanted in critical bone defects in rat calvaria. Seventy-two rats were randomly distributed in three groups: anionic collagen scaffolds treated for 24 h of selective hydrolysis (ACSH); anionic collagen scaffolds treated for 24 h of selective hydrolysis and 5 min of crosslinking in glutaraldehyde 0.05% (ACSHGA); empty bone defect (Control), evaluated at the biological points of 15, 45, 90 and 120 days. The results showed that the biomaterials implanted were biocompatible and showed a high osteogenic potential. These biomaterials presented a speed of biodegradation compatible with bone neoformation, which was shown to be associated with angiogenesis inside the scaffolds at all biological points. The percentage of mineralization of ACSH (87%) differed statistically from that found in ACSHGA (66%). It was concluded that the regeneration of critical bone defect was more evident in anionic collagen without crosslinking (ACSH).
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Affiliation(s)
- Fúlvio Borges Miguel
- Gonçalo Moniz Research Center, Oswaldo Cruz Foundation, Salvador, Bahia, Brazil,
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6
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McDade JK, Brennan-Pierce EP, Ariganello MB, Labow RS, Michael Lee J. Interactions of U937 macrophage-like cells with decellularized pericardial matrix materials: influence of crosslinking treatment. Acta Biomater 2013; 9:7191-9. [PMID: 23454057 DOI: 10.1016/j.actbio.2013.02.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 01/21/2013] [Accepted: 02/12/2013] [Indexed: 01/23/2023]
Abstract
While macrophages have been implicated in the failure of bioprosthetic heart valves, the macrophage response to crosslinked native pericardial collagen has not been previously investigated. Using decellularized bovine pericardium (DBP) as a model for native collagen, this study investigated the response of macrophage-like cells (U937s) to DBP, either: (i) untreated, or (ii) exogenously crosslinked with glutaraldehyde or 1-ethyl-3-(3-dimethyl-aminopropyl)-carbodiimide (EDC). We have previously validated the use of U937 cells as models for the response of human monocyte-derived macrophages to decellularized pericardial materials and, per our previous work, differentiated the U937 cells directly on the three material surfaces. After 72h in culture, the cells and medium were analyzed for DNA content, acid phosphatase activity, and cytokine and matrix metalloproteinase release. As well, cell/substrate samples were fixed for SEM. Fewer cells attached to or survived on the glutaraldehyde-treated substrate, and some showed an abnormal morphology compared to cells cultured on the other surfaces. Further, cells on glutaraldehyde-treated surfaces released more pro-inflammatory cytokines, more MMP-1 and less MMP-2 and MMP-9. The poor performance of the U937 macrophage-like cells on the glutaraldehyde-treated surfaces appears to be due to surface characteristics rather than to soluble aldehyde or other components leaching from the crosslinked material. These results provide evidence that crosslinking with glutaraldehyde is cytotoxic to macrophage-like cells, and that crosslinking with a zero-length crosslinker like EDC can be an acceptable alternative crosslinking treatment for biomaterials.
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7
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Guo H, Li T, Li J, Zhang M, Tang X. Kinetic Study of Modification of Collegen Peptide with Allyl Glycidyl Ether. PROGRESS IN REACTION KINETICS AND MECHANISM 2011. [DOI: 10.3184/146867810x12910391510836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The kinetics of reaction of collagen peptide with allyl glycidyl ether (AGE), and their temperature dependence, were studied by monitoring the reduction of the primary amine groups as a function of time. A kinetic model, with a second order with respect to the primary amine groups of collagen peptide and a first-order dependence on AGE, was developed that gave a good fit to the experimental data.
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Affiliation(s)
- Hong Guo
- Shandong Provincial Key Laboratory of Fine Chemicals (Shandong Institute of Light Industry), Jinan 250353, P. R. China
| | - Tianduo Li
- Shandong Provincial Key Laboratory of Fine Chemicals (Shandong Institute of Light Industry), Jinan 250353, P. R. China
| | - Junying Li
- Shandong Provincial Key Laboratory of Fine Chemicals (Shandong Institute of Light Industry), Jinan 250353, P. R. China
| | - Meng Zhang
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Xiaolong Tang
- Shandong Provincial Key Laboratory of Fine Chemicals (Shandong Institute of Light Industry), Jinan 250353, P. R. China
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8
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Willett TL, Labow RS, Aldous IG, Avery NC, Lee JM. Changes in Collagen With Aging Maintain Molecular Stability After Overload: Evidence From an In Vitro Tendon Model. J Biomech Eng 2010; 132:031002. [DOI: 10.1115/1.4000933] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Soft tissue injuries are poorly understood at the molecular level. Previous work using differential scanning calorimetry (DSC) has shown that tendon collagen becomes less thermally stable with rupture. However, most soft tissue injuries do not result in complete tissue rupture but in damaging fiber overextension. Covalent crosslinking, which increases with animal maturity and age, plays an important role in collagenous fiber mechanics. It is also a determinant of tissue strength and is hypothesized to inhibit the loss of thermal stability of collagen due to mechanical damage. Controlled overextension without rupture was investigated to determine if overextension was sufficient to reduce the thermal stability of collagen in the bovine tail tendon (BTT) model and to examine the effects of aging on the phenomenon. Baseline data from DSC and hydrothermal isometric tension (HIT) techniques were compared between two groups: steers aged 24–30 months (young group), and skeletally mature bulls and oxen aged greater than five years (old group). Covalent crosslinks were quantified by ion exchange chromatography. Overextension resulted in reduced collagen thermal stability in the BTT model. The Young specimens, showing detectably lower tissue thermomechanical competence, lost more thermal stability with overextension than did the old specimens. The effect on old specimens, while smaller, was detectable. Multiple overextension cycles increased the loss of stability in the young group. Compositional differences in covalent crosslinking corresponded with tissue thermomechanical competence and therefore inversely with the loss of thermal stability. HIT testing gave thermal denaturation temperatures similar to those measured with DSC. The thermal stability of collagen was reduced by overextension of the tendon—without tissue rupture—and this effect was amplified by increased cycles of overextension. Increased tissue thermomechanical competence with aging seemed to mitigate the loss of collagen stability due to mechanical overextension. Surprisingly, the higher tissue thermomechanical competence did not directly correlate with the concentration of endogenous enzymatically derived covalent crosslinking on a mole per mole of collagen basis. It did, however, correlate with the percentage of mature and thermally stable crosslinks. Compositional changes in fibrous collagens that occur with aging affect fibrous collagen mechanics and partially determine the nature of mechanical damage at the intermolecular level. As techniques develop and improve, this new information may lead to important future studies concerning improved detection, prediction, and modeling of mechanical damage at much finer levels of tissue hierarchy than currently possible.
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Affiliation(s)
- Thomas L. Willett
- Bone Biology Laboratory, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Rosalind S. Labow
- Department of Biochemistry, Microbiology and Immunology, Division of Cardiac Surgery, University of Ottawa Heart Institute, University of Ottawa, Ottawa, ON, K1Y 4W7, Canada
| | - Ian G. Aldous
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, B3M 3J5, Canada
| | - Nick C. Avery
- Matrix Biology Research Group, School of Clinical Veterinary Medicine, University of Bristol, Bristol BS40 5DU, UK
| | - J. Michael Lee
- Department of Applied Oral Sciences, School of Biomedical Engineering, Dalhousie University, Halifax, NS, B3H 3J5, Canada
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9
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Raman SS, Vijayaraj R, Parthasarathi R, Subramanian V, Ramasami T. A molecular dynamics analysis of ion pairs formed by lysine in collagen: Implication for collagen function and stability. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.theochem.2007.11.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Rehfeldt F, Engler AJ, Eckhardt A, Ahmed F, Discher DE. Cell responses to the mechanochemical microenvironment--implications for regenerative medicine and drug delivery. Adv Drug Deliv Rev 2007; 59:1329-39. [PMID: 17900747 PMCID: PMC4124491 DOI: 10.1016/j.addr.2007.08.007] [Citation(s) in RCA: 259] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 08/01/2007] [Indexed: 02/05/2023]
Abstract
Soft-tissue cells are surprisingly sensitive to the elasticity of their microenvironment, suggesting that traditional culture plastic and glass are less relevant to tissue regeneration and chemotherapeutics than might be achieved. Cells grown on gels that mimic the elasticity of tissue reveal a significant influence of matrix elasticity on adhesion, cytoskeletal organization, and even the differentiation of human adult derived stem cells. Cellular forces and feedback are keys to how cells feel their mechanical microenvironment, but detailed molecular mechanisms are still being elucidated. This review summarizes our initial findings for multipotent stem cells and also the elasticity-coupled effects of drugs on cancer cells and smooth muscle cells. The drugs include the contractility inhibitor blebbistatin, the proliferation inhibitor mitomycin C, an apoptotis-inducing antibody against CD47, and the translation inhibitor cycloheximide. The differential effects not only lend insight into mechano-sensing of the substrate by cells, but also have important implications for regeneration and molecular therapies.
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Affiliation(s)
- Florian Rehfeldt
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Adam J. Engler
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Adam Eckhardt
- Institute of Physiology, Czech Academy of Science, Prague, Czech Republic
| | - Fariyal Ahmed
- Department of Bioengineering, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Dennis E. Discher
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia PA 19104, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia PA 19104, USA
- Graduate Group of Physics & Astronomy, University of Pennsylvania, Philadelphia PA 19104, USA
- Corresponding author. Molecular & Cell Biophysics and NanoBio-Polymers Lab, University of Pennsylvania, Philadelphia PA 19104, USA. Tel.: +1 215 898 4809
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11
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Heldt JM, Fischer-Durand N, Salmain M, Vessières A, Jaouen G. The Use of Glycidol to Introduce Aldehyde Functions Into Proteins – Application to the Fluorescent Labelling of Bovine Serum Albumin and Avidin. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700429] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Gratzer PF, Santerre JP, Lee JM. The effect of chemical modification of amino acid side-chains on collagen degradation by enzymes. J Biomed Mater Res B Appl Biomater 2007; 81:1-11. [PMID: 16924626 DOI: 10.1002/jbm.b.30629] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study, the effects of specific chemical modifications of amino acid side-chains on the in vitro enzyme degradation of type I collagen was studied. Two monofunctional epoxides of different size and chemistry were used to modify lysine and methylglyoxal was used to modify arginine. Lysine residues were modified using glycidol, a small hydrophilic reagent or n-butylglycidylether, a larger hydrophobic reagent. Amino acid analysis, swelling measurements, in vitro enzyme degradation analyses (using either collagenase, trypsin, acetyltrypsin, or cathepsin B), and gel chromatography were used to determine the effects of each chemical modification on purified type I collagen. Collagen solubilization by enzymes depended upon the size and chemistry of epoxides used to modify lysine residues. Modification of lysine residues by glycidol and arginine modification by methylglyoxal together significantly reduced collagen solubilization by acetyltrypsin and collagenase, whereas increased collagen solubilization was observed for all enzymes after lysine modification with n-butylglycidylether combined with arginine modification by methylglyoxal. Gel chromatographic analyses of collagen fragments solubilized by acetyltrypsin from type I collagen revealed that both the extent of solubilization and sites of cleavage were altered after lysine and arginine modification. In contrast, lysine and arginine modification only altered the amount of collagen solubilized by collagenase and had no effect on the amount collagen solubilized by cathepsin B. The ability to modulate the enzyme degradation of collagen-based materials as demonstrated in this study may facilitate the design of novel scaffolds for tissue regeneration or collagen-based drug/protein/gene delivery systems.
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Affiliation(s)
- Paul F Gratzer
- School of Biomedical Engineering, Dalhousie University, 5981 University Avenue, Halifax, Nova Scotia, Canada B3H 1W2.
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13
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Tenni R, Sonaggere M, Viola M, Bartolini B, Tira ME, Rossi A, Orsini E, Ruggeri A, Ottani V. Self-aggregation of fibrillar collagens I and II involves lysine side chains. Micron 2006; 37:640-7. [PMID: 16714119 DOI: 10.1016/j.micron.2006.01.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Revised: 01/31/2006] [Accepted: 01/31/2006] [Indexed: 10/25/2022]
Abstract
Several properties of fibrillar collagens depend on abundance and position of ionic amino acids. We recently demonstrated that N-methylation and N-acetylation of Lys/Hyl amino group did not significantly alter the thermal stability of the triple helical conformation and that the binding of modified collagens I and II to decorin is lost only on N-acetylation. The positive charge at physiological pH of Lys/Hyl side chains is preserved only by N-methylation. We report here the new aspect of the influence of the same modifications on collagen self-aggregation in neutral conditions. Three collagen preparations are very differently affected by N-methylation: acid-soluble type I collagen maintains the ability to form banded fibrils with 67-nm periodicity, whereas almost no structured aggregates were detected for pepsin-soluble type I collagen; pepsin-soluble type II collagen forms a very different supramolecular species, known as segment long spacing (SLS). N-acetylation blocks the formation of banded fibrils in neutral conditions (as did all other chemical modifications reported in the literature), demonstrating that the positive charge of Lys/Hyl amino groups is essential for self-aggregation. Kinetic measurements by turbidimetry showed a sizeable increase of absorbance only for the two N-methylated samples forming specific supramolecular aggregates; however, the derivatization affects aggregation kinetics by increasing lag time and decreasing maximum slope of absorbance variation, and lowers aggregation competency. We discuss that the effects of N-methylation on self-aggregation are caused by fewer or weaker salt bridges and by decrease of hydrogen bonding potential and conclude that protonated Lys side chains are involved in the fibril formation process.
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Affiliation(s)
- Ruggero Tenni
- Dipartimento di Biochimica, A. Castellani, University of Pavia, via Taramelli 3b, 27100 Pavia, Italy
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14
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Abstract
Biomaterials research in Canada began in the 1960s. Over the past four decades significant contributions have been made across a broad spectrum covering dental, orthopaedic, cardiovascular, neuro, and ocular biomaterials. Canadians have also been active in the derivative area of tissue engineering. Biomaterials laboratories are now established in universities and research institutes from coast to coast, supported mainly by funding from the Federal and Provincial Governments. The Canadian Biomaterials Society was formed in 1971 and has played an important role in the development of the field. The Society played host to the 5th World Biomaterials Congress in Toronto in 1996. The work of Canadian researchers over the past four decades is summarized briefly. It is concluded that biomaterials and tissue engineering is a mature, strong area of research in Canada and appears set to continue as such into the future.
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Affiliation(s)
- John L Brash
- School of Biomedical Engineering and Department of Chemical Engineering, McMaster University, Hamilton, Ontario, Canada L8S 4L7.
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Abstract
Normal tissue cells are generally not viable when suspended in a fluid and are therefore said to be anchorage dependent. Such cells must adhere to a solid, but a solid can be as rigid as glass or softer than a baby's skin. The behavior of some cells on soft materials is characteristic of important phenotypes; for example, cell growth on soft agar gels is used to identify cancer cells. However, an understanding of how tissue cells-including fibroblasts, myocytes, neurons, and other cell types-sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels (or to other cells) with which elasticity can be tuned to approximate that of tissues. Key roles in molecular pathways are played by adhesion complexes and the actinmyosin cytoskeleton, whose contractile forces are transmitted through transcellular structures. The feedback of local matrix stiffness on cell state likely has important implications for development, differentiation, disease, and regeneration.
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Affiliation(s)
- Dennis E Discher
- School of Engineering and Applied Science and Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA 19104-6315, USA.
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