pinecone/core-2020-05-10-deduplication huggingface dataset:
Interactions between Schwann and olfactory ensheathing cells with a starch/polycaprolactone scaffold aimed at spinal cord injury repair

Spinal cord injury (SCI) represents a major world health problem. Therefore it is urgent to develop novel strategies that can specifically target it. We have previously shown that the implantation of starch-based scaffolds (SPCL) aimed for spine stabilization on SCI animals leads to motor skills improvements. Therefore, we hypothesize that the combination of these scaffolds with relevant cell populations for SCI repair will, most likely, lead to further improvements. Therefore, in this work, the ability of SPCL scaffolds to support the 3D culture of olfactory ensheathing cells (OECs) and Schwann cells (SCs) was studied and characterized. The results demonstrate for the first time that SPCL scaffolds were able to support the growth and migration of OECs and SCs. Moreover, the results indicate that two weeks of in vitro culture is the ideal time to reach a high number of transplantable cells. Future work will focus on the spine stabilization of SCI animals using SPCL scaffolds loaded with OECs or SCs for SCI regeneration.Foundation Calouste de GulbenkianPortuguese Foundation for Science and Technology (SFRH/BD/40684/2007
Growth factor release from a chemically modified elastomeric poly(1,8‐octanediol‐co‐citrate) thin film promotes angiogenesis  in vivo

The ultimate success of  in vivo  organ formation utilizing  ex vivo  expanded “starter” tissues relies heavily upon the level of vascularization provided by either endogenous or artificial induction of angiogenic or vasculogenic events. To facilitate proangiogenic outcomes and promote tissue growth, an elastomeric scaffold previously shown to be instrumental in the urinary bladder regenerative process was modified to release proangiogenic growth factors. Carboxylic acid groups on poly(1,8‐octanediol‐co‐citrate) films (POCfs) were modified with heparan sulfate creating a heparan binding POCf (HBPOCf). Release of proangiogenic growth factors vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and insulin‐like growth factor 1 (IGF‐1) from HBPOCfs demonstrated an approximate threefold increase over controls during a 30‐day time course  in vitro . Atomic force microscopy demonstrated significant topological differences between films. Subcutaneous implantation of POCf alone, HBPOCf, POCf‐VEGF, and HBPOCf‐VEGF within the dorsa of nude rats yielded increased vascular growth in HBPOCf‐VEGF constructs. Vessel quantification studies revealed that POCfs alone contained 41.1 ± 4.1 vessels/mm 2 , while HBPOCf, POCf‐VEGF, and HBPOCF‐VEGF contained 41.7 ± 2.6, 76.3 ± 9.4, and 167.72 ± 15.3 vessels/mm 2 , respectively. Presence of increased vessel growth was demonstrated by CD31 and vWF immunostaining in HBPOCf‐VEGF implanted areas. Data demonstrate that elastomeric POCfs can be chemically modified and possess the ability to promote angiogenesis  in vivo . © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012
An investigation into the effect of amphiphilic siloxane oligomers on dermal fibroblasts

This study investigates the effect of well-defined poly(dimethylsiloxane)-poly(ethylene glycol) (PDMS-PEG) ABA linear block co-oligomers on the proliferation of human dermal fibroblasts. The co-oligomers assessed ranged in molecular weight (MW) from 1335 to 5208 Da and hydrophilic-lipophilic balance (HLB) from 5.9 to 16.6 by varying the number of both PDMS and PEG units. In general, it was found that co-oligomers of low MW or intermediate hydrophilicity significantly reduced fibroblast proliferation. A linear relationship between down-regulation of fibroblast proliferation, and the ratio HLB/MW was observed at concentrations of 0.1 and 1.0 wt % of the oligomers. This enabled the structures with highest efficiency to be determined. These results suggest the possible use of the PEG-PDMS-PEG block co-oligomers as an alternative to silicone gels for hypertrophic scar remediation
Bioactive glass/polymer composite scaffolds mimicking bone tissue

The aim of this work was the preparation and characterization of scaffolds with mechanical and functional properties able to regenerate bone. Porous scaffolds made of chitosan/gelatin (POL) blends containing different amounts of a bioactive glass (CEL2), as inorganic material stimulating biomineralization, were fabricated by freeze-drying. Foams with different compositions (CEL2/POL 0/100; 40/60; 70/30 wt %/wt) were prepared. Samples were crosslinked using genipin (GP) to improve mechanical strength and thermal stability. The scaffolds were characterized in terms of their stability in water, chemical structure, morphology, bioactivity, and mechanical behavior. Moreover, MG63 osteoblast-like cells and periostealderived stem cells were used to assess their biocompatibility. CEL2/POL samples showed interconnected pores having an average diameter ranging from 179 6 5 lm for CEL2/POL 0/100 to 136 6 5 lm for CEL2/POL 70/30. GP-crosslinking and the increase of CEL2 amount stabilized the composites to water solution (shown by swelling tests). In addition, the SBF soaking experiment showed a good bioactivity of the scaffold with 30 and 70 wt % CEL2. The compressive modulus increased by increasing CEL2 amount up to 2.1 6 0.1 MPa for CEL2/POL 70/30. Dynamical mechanical analysis has evidenced that composite scaffolds at low requencies showed an increase of storage and loss modulus with increasing frequency; furthermore, a drop of E0 and E00 at 1 Hz was observed, and for higher frequencies both moduli increased again. Cells displayed a good ability to interact with the different tested scaffolds which did not modify cell metabolic activity at the analyzed points. MTT test proved only a slight difference between the two cytotypes analyze
Bioactive glass/polymer composite scaffolds mimicking bone tissue

The aim of this work was the preparation and
characterization of scaffolds with mechanical and functional
properties able to regenerate bone. Porous scaffolds made of
chitosan/gelatin (POL) blends containing different amounts of
a bioactive glass (CEL2), as inorganic material stimulating biomineralization,
were fabricated by freeze-drying. Foams with
different compositions (CEL2/POL 0/100; 40/60; 70/30 wt %/wt)
were prepared. Samples were crosslinked using genipin (GP)
to improve mechanical strength and thermal stability. The
scaffolds were characterized in terms of their stability in water,
chemical structure, morphology, bioactivity, and mechanical
behavior. Moreover, MG63 osteoblast-like cells and periostealderived
stem cells were used to assess their biocompatibility.
CEL2/POL samples showed interconnected pores having an
average diameter ranging from 179 6 5 lm for CEL2/POL 0/
100 to 136 6 5 lm for CEL2/POL 70/30. GP-crosslinking and
the increase of CEL2 amount stabilized the composites to
water solution (shown by swelling tests). In addition, the SBF
soaking experiment showed a good bioactivity of the scaffold
with 30 and 70 wt % CEL2. The compressive modulus increased
by increasing CEL2 amount up to 2.1 6 0.1 MPa for CEL2/POL
70/30. Dynamical mechanical analysis has evidenced that composite
scaffolds at low frequencies showed an increase of storage
and loss modulus with increasing frequency; furthermore,
a drop of E0 and E00 at 1 Hz was observed, and for higher frequencies
both moduli increased again. Cells displayed a good
ability to interact with the different tested scaffolds which did
not modify cell metabolic activity at the analyzed points. MTT
test proved only a slight difference between the two cytotypes
analyzed.Contract grant sponsor: Italian Ministry of University and Research for Piergiorgio Gentile's PhD GrantContract grant sponsor: FIRB project; contract grant number: RBAP10MLK
Bone tissue, cellular, and molecular responses to titanium implants treated by anodic spark deposition

A myriad of titanium (Ti) surface modifications has been proposed to hasten the osseointegration. In this context, the aim of this study was to perform histomorphometric, cellular, and molecular analyses of the bone tissue grown in close contact with Ti implants treated by anodic spark deposition (ASD-AK). Acid-etched (AE) Ti implants either untreated or submitted to ASD-AK were placed into dog mandibles and retrieved at 3 and 8 weeks. It was noticed that both implants, AE and ASD-AK, were osseointegrated at 3 and 8 weeks. Histomorphometric analysis showed differences between treatments only for bone-to-implant contact, being higher on AE implants. Although not backed by histomorphometric results, gene expression of key bone markers was higher for bone grown in close contact with ASD-AK and for cells harvested from these fragments and cultured until subconfluence. Cell proliferation at days 7 and 10 and alkaline phosphatase activity at day 10 was higher on AE surfaces. No statistical significant difference was noticed for extracellular matrix mineralization at 17 days. Our results have shown that the Ti fixtures treated by ASD-AK allowed in vivo osseointegration and induced higher expression of key markers of osteoblast phenotype, suggesting that this surface treatment could be considered to produce implants for clinical applications. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:30923098, 2012.Sao Paulo Research Foundation (FAPESP, Brazil)National Council for Scientific and Technological Development (CNPq, Brazil
Synthesis and characterization of sensitive hydrogels based on semi- interpenetrated networks of poly 2-ethyl-(2-pyrrolidone) methacrylate and hyaluronic acid

Sensitive hydrogels attract interest due to their soft wet appearance and shape response to environmental variations. The synthesis and characterization of semi-interpenetrated hydrogels obtained by radical-induced polymerization of 2-ethyl-(2-pyrrolidone)methacrylate (EPM) in the presence of different concentrations of hyaluronic acid (HA) using N,N′-methylene-bisacrylamide or triethylene glycol dimethacrylate as crosslinker, followed by freeze-drying, are described. Polymeric systems were characterized by NMR, FTIR, SEM, TGA, and DMA. PEPMHA hydrogels' mechanical properties and swelling were found to be intimately related to HA concentration and crosslinker. The swelling response was assessed for temperature and pH variation in order to study the behavior of the hydrogels. We found that the presence of HA in PEPM polymeric systems induced a sensitivity to pH variation rather than temperature. Finally, the biocompatibility profile of the hydrogels was evaluated, using mesenchymal stem cells. Cell adhesion and proliferation results revealed the non-cytotoxicity of the systems. We estimate that PEPMHA hydrogels can be used for applications in tissue engineering and for the controlled release of bioactive compounds.Contract grant sponsor: Marie Curie Early Stage Training Alea Jacta Est; contract grant number: MEST-CT-2004-8104The authors thank David Gomez, Sofia Caridade, and Justyna Chojnacka for their technical support and BIOIBERICA for the supply of hyaluronic acid. This work was carried out under the scope of the European NoE EXPERTISSUES, projects MAT 2007-63355, PTDC/QUI/68804/2006 (FCT), CIBER-BBN and Plan-E 2009-0144. In the memory of Prof. Roberto Sastre
Effect of fiber crosslinking on collagen-fiber reinforced collagen-chondroitin-6-sulfate materials for regenerating load-bearing soft tissues

Porous collagen–glycosaminoglycan structures are bioactive and exhibit a pore architecture favorable for both cellular infiltration and attachment; however, their inferior mechanical properties limit use, particularly in load-bearing situations. Reinforcement with collagen fibers may be a feasible route for enhancing the mechanical characteristics of these materials, providing potential for composites used for the repair and regeneration of soft tissue such as tendon, ligaments, and cartilage. Therefore, this study investigates the reinforcement of collagen–chondroitin-6-sulfate (C6S) porous structures with bundles of extruded, reconstituted type I collagen fibers. Fiber bundles were produced through extrusion and then, where applicable, crosslinked using a solution of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide. Fibers were then submerged in the collagen–C6S matrix slurry before being lyophilized. A second 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide crosslinking process was then applied to the composite material before a secondary lyophilization cycle. Where bundles had been previously crosslinked, composites withstood a load of approximately 60 N before failure, the reinforcing fibers remained dense and a favorable matrix pore structure resulted, with good interaction between fiber and matrix. Fibers that had not been crosslinked before lyophilization showed significant internal porosity and a channel existed between them and the matrix. Mechanical properties were significantly reduced, but the additional porosity could prove favorable for cell migration and has potential for directing aligned tissue growth.This is the pre-peer reviewed version of the following article: J.H. Shepherd, S. Ghose, A. Moavenian, S.J. Kew, S.M. Best and R.E. Cameron. “Effect of fibre Cross-linking on Collagen-fibre reinforced Collagen-chondroitin-6-sulphate materials for regenerating load-bearing soft tissues”. Journal of Biomedical Materials Research: Part A, 2013;101(1):176-84., which has been published in final form at http://dx.doi.org/10.1002/jbm.a.34317
Different hyaluronic acid morphology modulates primary articular chondrocyte behavior in hyaluronic acid-coated polycaprolactone scaffolds

Scaffolds for cartilage tissue engineering should
promote both adequate biomechanical environment and
chondrogenic stimulation. Hyaluronic acid (HA) has been
used in cartilage engineering for its chondrogenic and
chondroprotective properties, nevertheless its mechanical
properties are limited. Influence of HA microstructure in
chondrocyte response has not been addressed yet. In this
work, polycaprolactone (PCL) scaffolds were modified using
HA following two coating strategies: coating in one step
(PCL-HA1s) yields a gel-like phase within the scaffold,
whereas a two-step reaction (PCL-HA2s) yields a thin HA
layer coating internal surfaces of PCL structure. Chondrocytes
were seeded in the scaffolds and cultured in dedifferentiating
conditions up to 3 weeks and analyzed using a total DNA
assay and sulfated glycosaminoglycan (sGAG) determination
assay; cell morphology and extracellular matrix secretion
were assessed by electron microscopy as well as immunofluorescent imaging (collagen I, collagen II, aggrecan, CD44).
Cells proliferate in all samples and no cytotoxicity is observed.
PCL-HA1s shows higher sGAG production per cell than PCL
and PCL-HA2s at all times. Presence of hyaluronic acid promotes
qualitative expression of CD44 surface markers and
aggrecan (more visible in PCL-HA1s than PCL-HA2s), whereas
in dedifferentiating conditions, expression of CD44 and aggrecan
can hardly be detected in pure PCL scaffolds. Collagen
type II seems more prominent in PCL-HA2s; although PCLHA2s
shows markers for COL II, aggrecan and CD44, quantitative
ECM production is not improved with respect to PCL. It is
thus likely that CD44 activation is not sufficient for explaining
the better response in PCL-HA1s.Contract grant sponsor: Valencia Polytechnic University; contract grant number: PAID-06-10Contract grant sponsor: Spanish Ministry of Science; contract grant number: MAT2010-21611-C03-01Contract grant sponsors: CIBER-BBN; VI National R&D&i Plan 2008-2011; Iniciativa Ingenio 2010; Consolider Program; Instituto de Salud Carlos III; European Regional Development Fund; Valencian Generality; Conselleria de Sanidad (Generalitat Valenciana
Subcutaneous tissue response to titanium, poly(ϵ‐caprolactone), and carbonate‐substituted hydroxyapatite‐coated poly(ϵ‐caprolactone) plates: A rabbit study

The aim of this study was to evaluate the soft tissue response to poly(ϵ‐caprolactone) (PCL) implants with and without carbonate‐substituted hydroxyapatite (CHA) coating compared to the commonly used titanium alloy (Ti‐6Al‐4V)‐machined surface. Experimental materials were implanted subcutaneously in New Zealand white rabbits for 5 weeks. The tissue attachment strength, as evaluated by a tissue peel test, histological and histomorphology analysis, as well as scanning electron microscopy were compared between groups. The peel test result revealed no statistically significant difference between groups. Histological analysis found fibrous capsule formation around all implant materials. The fibrous capsule around PCL implants with and without CHA coating was significantly thinner compared with the capsule thickness around the titanium implants. However, the inflammatory cells, as present at the fibrous capsule‐implant interface, were found to be significantly lower in  the  Ti‐group. In conclusion, the current data do not prove that PCL or PCL with a CHA coating results in a superior soft tissue response compared with a machined titanium implant. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013
Winner for outstanding research in the Ph.D. category for the 2013 society for biomaterials meeting and exposition, April 10–13, 2013, Boston, Massachusetts

Modular tissue engineering applies biomaterials‐based approaches to create discrete cell‐seeded microenvironments, which can be further assembled into larger constructs for the repair of injured tissues. In the current study, we embedded human bone marrow‐derived mesenchymal stem cells (MSC) and human adipose‐derived stem cells (ASC) in collagen/fibrin (COL/FIB) and collagen/fibrin/hydroxyapatite (COL/FIB/HA) microbeads, and evaluated their suitability for bone tissue engineering applications. Microbeads were fabricated using a water‐in‐oil emulsification process, resulting in an average microbead diameter of approximately 130 ± 25 μm. Microbeads supported both cell viability and cell spreading of MSC and ASC over 7 days in culture. The embedded cells also began to remodel and compact the microbead matrix as demonstrated by confocal reflectance microscopy imaging. After two weeks of culture in media containing osteogenic supplements, both MSC and ASC deposited calcium mineral in COL/FIB microbeads, but not in COL/FIB/HA microbeads. There were no significant differences between MSC and ASC in any of the assays examined, suggesting that either cell type may be an appropriate cell source for orthopedic applications. This study has implications in the creation of defined microenvironments for bone repair, and in developing a modular approach for delivery of pre‐differentiated cells. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013
Rheological and mechanical properties of acellular and cellladen methacrylated gellan gum hydrogels

Tissue engineered hydrogels hold great potential as nucleus pulposus substitutes (NP), as they promote intervertebral disc (IVD) regeneration and re-establish its original function. But, the key to their success in future clinical applications greatly depends on its ability to replicate the native 3D micro-environment and circumvent their limitation in terms of mechanical performance. In the present study, we investigated the rheological/mechanical properties of both ionic- (iGG-MA) and photo-crosslinked methacrylated gellan gum (phGG-MA) hydrogels. Steady shear analysis, injectability and confined compression stress-relaxation tests were carried out. The injectability of the reactive solutions employed for the preparation of iGG-MA and phGG-MA hydrogels was firstly studied, then the zero-strain compressive modulus and permeability of the acellular hydrogels were evaluated.In addition, human intervertebral disc (hIVD) cells encapsulated in both iGG-MA and phGG-MA hydrogels were cultured in vitro, and its mechanical properties also investigated under dynamic mechanical analysis at 37ºC and pH 7.4. After 21 d of culturing, hIVD cells were alive (Calcein AM) and the E’ of ionic-crosslinked hydrogels and photo-crosslinked was higher than that observed for acellular hydrogels. Our study suggests that methacrylated gellan gum hydrogels present promising mechanical and biological performance as hIVD cells were producing extracellular matrix
Chitosan-collagen scaffolds with nano/microfibrous architecture for skin tissue engineering

In this study, a hierarchical nano/microfibrous chitosan/collagen scaffold that approximates structural and functional attributes of native extracellular matrix (ECM), has been developed for applicability in skin tissue engineering. Scaffolds were produced by electrospinning of chitosan followed by imbibing of collagen solution, freeze-drying and subsequent cross-linking of two polymers. Scanning electron microscopy showed formation of layered scaffolds with nano/microfibrous architechture. Physico-chemical properties of scaffolds including tensile strength, swelling behavior and biodegradability were found satisfactory for intended application. 3T3 fibroblasts and HaCaT keratinocytes showed good in vitro cellular response on scaffolds thereby indicating the matrices′ cytocompatible nature. Scaffolds tested in an ex vivo human skin equivalent (HSE) wound model, as a preliminary alternative to animal testing, showed keratinocyte migration and wound re-epithelization — a pre-requisite for healing and regeneration. Taken together, the herein proposed chitosan/collagen scaffold, shows good potential for skin tissue engineering
Sustained delivery of bioactive TGF-β1 from self-assembling peptide hydrogels induces chondrogenesis of encapsulated bone marrow stromal cells

Tissue engineering strategies for cartilage defect repair require technology for local targeted delivery of chondrogenic and anti-inflammatory factors. The objective of this study was to determine the release kinetics of transforming growth factor β1 (TGF-β1) from self-assembling peptide hydrogels, a candidate scaffold for cell transplant therapies, and stimulate chondrogenesis of encapsulated young equine bone marrow stromal cells (BMSCs). Although both peptide and agarose hydrogels retained TGF-β1, fivefold higher retention was found in peptide. Excess unlabeled TGF-β1 minimally displaced retained radiolabeled TGF-β1, demonstrating biologically relevant loading capacity for peptide hydrogels. The initial release from acellular peptide hydrogels was nearly threefold lower than agarose hydrogels, at 18% of loaded TGF-β1 through 3 days as compared to 48% for agarose. At day 21, cumulative release of TGF-β1 was 32–44% from acellular peptide hydrogels, but was 62% from peptide hydrogels with encapsulated BMSCs, likely due to cell-mediated TGF-β1 degradation and release of small labeled species. TGF-β1 loaded peptide hydrogels stimulated chondrogenesis of young equine BMSCs, a relevant preclinical model for treating injuries in young human cohorts. Self-assembling peptide hydrogels can be used to deliver chondrogenic factors to encapsulated cells making them a promising technology for in vivo, cell-based regenerative medicine.National Institutes of Health (U.S.) (NIH EB003805)National Institutes of Health (U.S.) (NIH AR60331)National Institutes of Health (U.S.). Molecular, Cell, and Tissue Biomechanics (Training Grant Fellowship)Arthritis Foundation (postdoctoral fellowship