Silk fibroin/chondroitin sulfate/hyaluronic acid ternary scaffolds for dermal tissue reconstruction

A nano zinc oxide doped electrospun scaffold improves wound healing in a rodent model

Development of new and effective wound dressing materials continues to be an area of intense research in wound care management. ​Fabricated ZnO doped nanofibrous scaffold exhibited proficiency in EPCs enrichment and wound healing.

Hybrid scaffolding strategy for dermal tissue reconstruction: a bioactive glass/chitosan/silk fibroin composite

Regeneration of deep burn wounds is a very complex process that strongly relies on the tissue response between the dermal substitute and the newly-formed dermis.

Use of Mesothelial Cells and Biological Matrices for Tissue Engineering of Simple Epithelium Surrogates

Tissue-engineering technologies have progressed rapidly through last decades resulting in the manufacture of quite complex bioartificial tissues with potential use for human organ and tissue regeneration. The manufacture of avascular monolayered tissues such as simple squamous epithelia was initiated a few decades ago and is attracting increasing interest. Their relative morphostructural simplicity makes of their biomimetization a goal, which is currently accessible. The mesothelium is a simple squamous epithelium in nature and is the monolayered tissue lining the walls of large celomic cavities (peritoneal, pericardial, and pleural) and internal organs housed inside. Interestingly, mesothelial cells can be harvested in clinically relevant numbers from several anatomical sources and not less important, they also display high transdifferentiation capacities and are low immunogenic characteristics, which endow these cells with therapeutic interest. Their combination with a suitable scaffold (biocompatible, degradable, and non-immunogenic) may allow the manufacture of tailored serosal membranes biomimetics with potential spanning a wide range of therapeutic applications, principally for the regeneration of simple squamous-like epithelia such as the visceral and parietal mesothelium vascular endothelium and corneal endothelium among others. Herein, we review recent research progresses in mesothelial cells biology and their clinical sources. We make a particular emphasis on reviewing the different types of biological scaffolds suitable for the manufacture of serosal mesothelial membranes biomimetics. Finally, we also review progresses made in mesothelial cells-based therapeutic applications and propose some possible future directions.

Evaluation of emulsion electrospun polycaprolactone/hyaluronan/epidermal growth factor nanofibrous scaffolds for wound healing

Wound healing scaffolds provide cells with structural integrity and can also deliver biological agents to establish a skin tissue-specific microenvironment to regulate cell functions and to accelerate the healing process. In this study, we fabricated biodegradable nanofibrous scaffolds with an emulsion electrospinning technique. The scaffolds were composed of polycaprolactone, hyaluronan and encapsulating epidermal growth factor. The morphology and core-sheath structure of the nanofibers were characterized by scanning electron microscopy and transmission electron microscopy. The scaffolds were also characterized for chemical composition and hydrophilicity with a Fourier-transform infrared analysis, energy dispersive spectroscopy and the water contact angle. An in vitro model protein bovine serum albumin and epidermal growth factor release study was conducted to evaluate the sustained release potential of the core-sheath structured nanofibers with and without the hyaluronan component. Additionally, an in vitro cultivation of human skin keratinocytes (HaCaT) and fibroblasts on polycaprolactone/hyaluronan and polycaprolactone/hyaluronan-epidermal growth factor scaffolds showed a significant synergistic effect of hyaluronan and epidermal growth factor on cell proliferation and infiltration. Furthermore, there was an up-regulation of the wound-healing-related genes collagen I, collagen III and TGF-β in polycaprolactone/hyaluronan/epidermal growth factor scaffolds compared with control groups. In the full-thickness wound model, the enhanced regeneration of fully functional skin was facilitated by epidermal regeneration in the polycaprolactone/hyaluronan/epidermal growth factor treatment group. Our findings suggest that bioactivity and hemostasis of the hyaluronan-based nanofibrous scaffolds have the capability to encapsulate and control the release of growth factors that can serve as skin tissue engineering scaffolds for wound healing.

Natural polysaccharides promote chondrocyte adhesion and proliferation on magnetic nanoparticle/PVA composite hydrogels

This paper aims to investigate the synergistic effects of natural polysaccharides and inorganic nanoparticles on cell adhesion and growth on intrinsically cell non-adhesive polyvinyl alcohol (PVA) hydrogels. Previously, we have demonstrated that Fe2O3 and hydroxyapatite (nHAP) nanoparticles are effective in increasing osteoblast growth on PVA hydrogels. Herein, we blended hyaluronic acid (HA) and chondroitin sulfate (CS), two important components of cartilage extracellular matrix (ECM), with Fe2O3/nHAP/PVA hydrogels. The presence of these natural polyelectrolytes dramatically increased the pore size and the equilibrium swelling ratio (ESR) while maintaining excellent compressive strength of hydrogels. Chondrocytes were seeded and cultured on composite PVA hydrogels containing Fe2O3, nHAP and Fe2O3/nHAP hybrids and Fe2O3/nHAP with HA or CS. Confocal laser scanning microscopy (CLSM) and cell counting kit-8 (CCK-8) assay consistently confirmed that the addition of HA or CS promotes chondrocyte adhesion and growth on PVA and composite hydrogels. Particularly, the combination of HA and CS exhibited further promotion to cell adhesion and proliferation compared with any single polysaccharide. The results demonstrated that the magnetic composite nanoparticles and polysaccharides provided synergistic promotion to cell adhesion and growth. Such polysaccharide-augmented composite hydrogels may have potentials in biomedical applications.

Buccal mucosa repair with electrospun silk fibroin matrix in a rat model

INTRODUCTION

Biomimic electrospun matrix derived from silk fibroin nanofiber solution was recently prepared in our group. The feasibility of the matrix as mucosa repair scaffold was evaluated in a rat model in the present study.

METHODS

Full thickness wound was established on the buccal mucosa of male Wister rats via microscopic oral surgery. 80 rats were randomly assigned into 4 groups: (1) silk fibroin matrix, (2) commercial cowhide acellular dermal matrix (Heal-All), (3) commercial acellular dermal matrix of human skin (RENOV), and (4) vaseline gauze, respectively.

RESULTS

The silk fibroin matrix showed similar repair performance compared to the commercial acellular dermal matrices, implying promising applications in mucosa regeneration. More importantly, the silk fibroin matrix showed better wound healing ability, improved wound shrinkage inhibition, and reduced local immunological incompatibility.

CONCLUSIONS

The silk fibroin scaffold performed satisfied in scar tissue inhibition and epidermis regeneration. Taking into account its improved mechanical properties, the biomimic electrospun silk matrix could become a promising substitute of acellular dermal matrix in clinical applications.

Collagen scaffold arrays for combinatorial screening of biophysical and biochemical regulators of cell behavior

Arrays of 3D macroporous collagen scaffolds with orthogonal gradations of structural and biomolecular cues are described. Gradient maker technology is applied to create linear biomolecular gradients within microstructurally distinct sections of a single CG scaffold array. The array set up is used to explore cell behaviors including proliferation and regulation of stem cell fate.

Silk fibroin–keratin based 3D scaffolds as a dermal substitute for skin tissue engineering

Development of highly vascular dermal tissue-engineered skin substitutes with appropriate mechanical properties and cellular cues is in need for significant advancement in the field of dermal reconstruction.

Fabrication of a novel blended membrane with chitosan and silk microfibers for wound healing: characterization, in vitro and in vivo studies

A novel type of chitosan/silk microfibers blended membrane was fabricated, which could significantly accelerate wound healing efficiency.

Interpenetrated 3D porous scaffolds of silk fibroin with an amino and octadecyl functionalized hyaluronic acid

A functionalized HA derivative (HA–EDA–C₁₈) was processed with silk fibroin via a salt leaching procedure to produce stable porous scaffolds for biomedical applications. The HA derivative was able to induce β-sheet transitions on fibroin.

Highly flexible and conductive composite films of silk fibroin and silver nanowires for optoelectronic devices

Silver nanowire-coated silk fibroin composite films assisted by ion sputtering exhibited excellent flexibility, conductivity, which used to light LED device.

Green fabrication of porous silk fibroin/graphene oxide hybrid scaffolds for bone tissue engineering

The porous SF/GO scaffolds with moderate GO content could promote the proliferation of osteoblasts.

Effect of silk fibroin nanofibers containing silver sulfadiazine on wound healing

BACKGROUND

One of the promising applications of silk fibroin (SF) in biomedical engineering is its use as a scaffolding material for skin regeneration. The purpose of this study was to determine the wound healing effect of SF nanofibrous matrices containing silver sulfadiazine (SSD) wound dressings.

METHODS

An SF nanofibrous matrix containing SSD was prepared by electrospinning. The cell attachment and spreading of normal human epidermal keratinocytes (NHEK) and normal human epidermal fibroblasts (NHEF) to SF nanofibers containing three different concentrations of SSD contents (0.1, 0.5, and 1.0 wt%) were determined. In addition, a rat wound model was used in this study to determine the wound healing effect of SF nanofibers containing SSD compared with that of Acticoat™, a commercially available wound dressing.

RESULTS

The number of NHEK and NHEF attached to SF nanofibers containing SSD decreased when the concentration of SSD increased. The number of attached NHEF cells was lower than that of attached NHEK cells. The SF matrix with 1.0 wt% SSD produced faster wound healing than Acticoat, although 1.0 wt% SSD inhibited the attachment of epidermal cells to SF nanofibers in vitro.

CONCLUSION

The cytotoxic effects of SF nanofibers with SSD should be considered in the development of silver-release dressings for wound healing through its antimicrobial activity. It is challenging to design wound dressings that maximize antimicrobial activity and minimize cellular toxicity.

Platelet lysate embedded scaffolds for skin regeneration

INTRODUCTION

The work presents the development of acellular scaffolds extemporaneously embedded with platelet lysate (PL), as an innovative approach in the field of tissue regeneration/reparation. PL embedded scaffolds should have a tridimensional architecture to support cell migration and growth, in order to restore skin integrity. For this reason, chondroitin sulfate (CS) was associated with sodium alginate (SA) to prepare highly porous systems.

METHODS

The developed scaffolds were characterized for chemical stability to γ-radiation, morphology, hydration and mechanical properties. Moreover, the capability of fibroblasts and endothelial cells to populate the scaffold was evaluated by means of proliferation test 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and confocal laser scanning microscopy study. The scaffolds, not altered by sterilization, were characterized by limited swelling and high flexibility, by foam-like structure with bubbles that formed a high surface area and irregular texture suitable for cell adhesion.

RESULTS

Cell growth and scaffold population were evident on the bubble surface, where the cells appeared anchored to the scaffold structure.

CONCLUSION

Scaffold network based on CS and SA demonstrated to be an effective support to enhance and to allow fibroblasts and endothelial cells (human umbilical vein endothelial cells, HUVEC) adhesion and proliferation. In particular, it could be hypothesized that cell adhesion was facilitated by the synergic effect of PL and CS. Although further in vivo evaluation is needed, on the basis of in vitro results, PL embedded scaffolds seem promising systems for skin wound healing.

Therapeutic efficacy of antibiotic-loaded gelatin microsphere/silk fibroin scaffolds in infected full-thickness burns

Despite advances in burn treatment, burn infection remains a major cause of morbidity and mortality. In this study, an antibacterial silk fibroin (SF) scaffold for burn treatment was designed; gelatin microspheres (GMs) were impregnated with the antibiotic gentamycin sulfate (GS), and the GS-impregnated GMs were then embedded in a SF matrix to fabricate GS/GM/SF scaffolds. The developed GS/GM/SF scaffolds could serve as a dermal regeneration template in full-thickness burns. The average pore size and porosity of the GS/GM/SF scaffolds were 40-80 μm and 85%, respectively. Furthermore, the drug release rate of the scaffolds was significantly slower than that of either GS/GM or GS/SF scaffolds. And the composite scaffold exhibited stronger antimicrobial activities against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Hence, we evaluated the wound-healing effects and antibacterial properties of the GS/GM/SF scaffolds in a rat full-thickness burn infection model. Over 21 days, the GS/GM/SF scaffolds not only significantly reduced burn infection by P. aeruginosa but also accelerated the regeneration of the dermis and exhibited higher epithelialization rates than did GS/SF and SF scaffolds. Thus, GS/GM/SF scaffolds are potentially effective for treatment of full-thickness infected burns, and GS/GM/SF scaffolds are a promising therapeutic tool for severely burned patients.

Bioengineered silk gene delivery system for nuclear targeting

Gene delivery research has gained momentum with the use of lipophilic vectors that mimic viral systems to increase transfection efficiency. Maintaining cell viability with these systems remains a major challenge. Therefore, biocompatible biopolymers that are designed by combining non-immunological viral mimicking components with suitable carrier are explored to address these limitations. In the present study, dragline silk recombinant proteins are modified with DNA condensing units and the proton sponge endosomal escape pathway is utilized for enhanced delivery. Transfection efficiency in a COS-7 cell line is enhanced compared to lipofectamine and polyethyleneimine (PEI), as is cell viability.

Polysaccharides as Cell Carriers for Tissue Engineering: the Use of Cellulose in Vascular Wall Reconstruction

Polysaccharides are long carbohydrate molecules of monosaccharide units joined together by glycosidic bonds. These biological polymers have emerged as promising materials for tissue engineering due to their biocompatibility, mostly good availability and tailorable properties. This complex group of biomolecules can be classified using several criteria, such as chemical composition (homo- and heteropolysaccharides), structure (linear and branched), function in the organism (structural, storage and secreted polysaccharides), or source (animals, plants, microorganisms). Polysaccharides most widely used in tissue engineering include starch, cellulose, chitosan, pectins, alginate, agar, dextran, pullulan, gellan, xanthan and glycosaminoglycans. Polysaccharides have been applied for engineering and regeneration of practically all tissues, though mostly at the experimental level. Polysaccharides have been tested for engineering of blood vessels, myocardium, heart valves, bone, articular and tracheal cartilage, intervertebral discs, menisci, skin, liver, skeletal muscle, neural tissue, urinary bladder, and also for encapsulation and delivery of pancreatic islets and ovarian follicles. For these purposes, polysaccharides have been applied in various forms, such as injectable hydrogels or porous and fibrous scaffolds, and often in combination with other natural or synthetic polymers or inorganic nanoparticles. The immune response evoked by polysaccharides is usually mild, and can be reduced by purifying the material or by choosing appropriate crosslinking agents.

Beneficial effects of hyaluronic acid

Biomaterials are playing a vital role in our day-to-day life. Hyaluronan (hyaluronic acid), a biomaterial, receives special attention among them. Hyaluronic acid (HA) is a polyanionic natural polymer occurring as linear polysaccharide composed of glucuronic acid and N-acetylglucosamine repeats via a β-1,4 linkage. It is the most versatile macromolecule present in the connective tissues of all vertebrates. Hyaluronic acid has a wide range of applications with its excellent physicochemical properties such as biodegradability, biocompatibility, nontoxicity, and nonimmunogenicity and serves as an excellent tool in biomedical applications such as osteoarthritis surgery, ocular surgery, plastic surgery, tissue engineering, and drug delivery. It plays a key role in cushioning and lubricating the body and is abundant in the eyes, joints, and heart valves. A powerful antioxidant, hyaluronic acid is perhaps best known for its ability to bond water to tissue. Hyaluronan production increases in proliferating cells, and the polymer may play a role in mitosis. This chapter gives an overview of hyaluronic acid and its physicochemical properties and applications. This chapter gives a deep understanding on the special benefits of hyaluronic acid in the fields of pharmaceutical, medical, and environmental applications. Hyaluronic acid paves the way for beneficial research and applications to the welfare of life forms.