Mushroom Pulp Tissue-Based Membrane-Ferrocene-Modified L-Tyrosine Biosensor

A new approach for assembling amperometric mushroom pulp tissue based membrane electrode for determination of L tyrosine analysis is proposed. Ferrocene is used as a mediator of electron transfer between tyrosinase in mushroom tissue and a graphite electrode. The optimal operation conditions are studied. The linear response range of the biosensor is 2 0×10 -4 to 4 5×10 -3 mol·L -1 with response time of less than 5 min and lifetime of at least 30 d. The biosensor can be applied to practical sample analysis.

Amniotic membrane as a potent source of stem cells and a matrix for engineering heart tissue

Existing therapies for the treatment of chronic heart failure still have some limitations and there is a pressing need for the development of new therapeutic modalities. The amniotic membrane has been used for the treatment of various diseases, such as conjunctive defects;however, the mechanisms behind its repair functions are still unclear. Regenerative medicine is seeking newer alternatives and among them, biomaterials have emerged in recent years for developing and manipulating molecules, cells, tissues or organs grown in laboratories in order to replace human body parts. Many such materials have been used for this purpose, either synthetically or biologically, in order to provide new medical devices. This review provides a wider view of the regeneration potential of the use of amniotic membrane as a potential biomaterial to facilitate the implementation of new research in surgical procedures. Amniotic membrane appears to be an alternative source of stem cells as well as an excellent biomaterial for cell-based therapeutic applications in engineering heart tissue.

Functionalized Asymmetric Poly (Lactic Acid)/Gelatin Composite Membrane for Guided Periodontal Tissue Regeneration

Aim: Periodontitis is caused by chronic gingival inflammation and affects a large population in the world. Although guided tissue regeneration (GTR) therapy has been proven to be an effective treatment, the deficiency in the symmetrical design of all the GTR membrane in the market leaves large space for improvement. Therefore, we designed a novel asymmetrical bi-layer PLA/gelatin composite membrane for treating periodontitis. Methods: The PLA side was fabricated by electrospinning with metronidazole (MNA) pre-mixed with the PLA solution. The gelatin side containing bioglass (BG) 45S5 was fabricated with freeze-drying process and cross-linked with PLA membrane. The bio-compatibility of the membrane was evaluated in vitro using NIH3T3 cells. The releasing of MNA was measured by spectrophotometer. The bioactivity of the membrane was evaluated by hydroxyapatite (HA) deposit and determined by FTIR spectrometer. The ionic concentration of Ca2+ and was measured by ICPOES. The expression of the osteogenesis makers was determined by qRT-PCR. Results: The bi-layer PLA/gelatin composite membrane is biocompatible and bioactive. The releasing of MNA can rapidly reach the anti-bacterial effective concentration. Interestingly, the incorporation of MNA modulated the degradation rate of PLA scaffold to meet the requirement of tissue regeneration. Meanwhile, the embedding of the BG powder in the gelatin porous layer provided a favorable Ca2+ and ion environment for the regeneration of the alveolar bone tissue. Conclusions: Taken together, this bi-layer GTR membrane is closer to the physiological structure of the periodontal. The addition of MNA and BG makes it more powerful in treating periodontitis. Moreover, this research provides an example of biomimetic design in fabricating biomaterial for clinical applications.

Human amniotic membrane and nerve tissue engineering

Totally three articles focusing on ＂the effects of microenvironment for human amniotic epithelial cell transplantation on cell survival and differentiation, the migration of human amniotic epithelial cells after in vitro transplantation, and the rheological characteristics of anastomosing injured sciatic nerve with human amniotic membrane without amniotic epithelial cells＂ are published in three issues. We hope that our readers find these papers useful to their research.

GUIDED TISSUE REGENERATION AROUND DENTAL IMPLANTS IN IMMEDIATE EXTRACTION SOCKETS:COMPARISON OF RESORBABLE ANDNONRESORBABLE MEMBRANES

This study was per formed to compare the efficacy of guided tissue regeneration (GTR) around dentalimplants immediately placed into extraction sockets by resorbable of nonresorbable membranes. Mandibular. P2, P3, and P4 of four aduIt beagle dogs were extracted bilaterally, and buccal standard defects were cre-ated and measured. Eighteen commercially pure titanium Steri-Oss implant fixtures were placed into thefresh extraction sockets. Four implants were untreated controls, four implants received polytetrafluoro-ethylene (e-PTFE, Gore-Tex) membranes, five implants received collagen membranes (ParaGuide), andfive implants received polyglactin 910 mesh (Vicryl). After l4 weeks, clinical measurements were takenand the dogs were sacrificed and all specimens retrieved for histologic and histomorphometric evaluation.The average gain in bone height was 2. 1mm for untreated control sites, 3. 3mm for Gore-Tex sites,3. 8mm for collagen sites, and 1. 3mm for polyglactin 910 sites. The greatest gain in bone height and volume was seen for two sites that received Gore-Tex membranes and remained covered for the entire evalua-tion interval. The results of this study indicate that Gore-Tex and collagen membrane preduced gdri re-sults for GTR around Implants immediately placed into extraction sockets. Since collagen membrane doesnot cause obvious infection and does not need the surgical reentry for membrane removal, it can be a validalternative to Gore-Tex membrane to improve bone regeneration around dental implants, while polyglactin910 mesh seems not suitable to be used as GTR membrane in immediate implantation for its hIgh infectionrate.

Corn Umbilicus Tissue-Based Membrane Biosensor for Pyruvate

Pyruvate, a final metabolite of glycogen, is widely distributed over many kinds of tissue fluids of human bodys. The determination for its contents is of clinical importance in gynaecology. Titrimetry, colorimetry and chromatography are common used methods. In recent years, enzymatic mthod has proved to be one of the most important determination techniques for its simplicity and fastness. However, in some cases, the use of purified enzymes as biocatalysts yields systems with a short useful lifetime owing, to enzyme instability A tiss

Large-Scale Surface Modification of Decellularized Matrix with Erythrocyte Membrane for Promoting In Situ Regeneration of Heart Valve

In situ regeneration is a promising strategy for constructing tissue engineering heart valves(TEHVs).Currently,the decellularized heart valve(DHV)is extensively employed as a TEHV scaffold.Nevertheless,DHV exhibits limited blood compatibility and notable difficulties in endothelialization,resulting in thrombosis and graft failure.The red blood cell membrane(RBCM)exhibits excellent biocompatibility and prolonged circulation stability and is extensively applied in the camouflage of nanoparticles for drug delivery;however,there is no report on its application for large-scale modification of decellularized extracellular matrix(ECM).For the first time,we utilized a layer-by-layer assembling strategy to immobilize RBCM on the surface of DHV and construct an innovative TEHV scaffold.Our findings demonstrated that the scaffold significantly improved the hemocompatibility of DHV by effectively preventing plasma protein adsorption,activated platelet adhesion,and erythrocyte aggregation,and induced macrophage polarization toward the M2 phenotype in vitro.Moreover,RBCM modification significantly enhanced the mechanical properties and enzymatic stability of DHV.The rat models of subcutaneous embedding and abdominal aorta implantation showed that the scaffold regulated the polarization of macrophages into the anti-inflammatory and pro-modeling M2 phenotype and promoted endothelialization and ECM remodeling in the early stage without thrombosis and calcification.The novel TEHV exhibits excellent performance and can overcome the limitations of commonly used clinical prostheses.

Mesenchymal stromal cells from human perinatal tissues: From biology to cell therapy

Cell-based regenerative medicine is of growing interest in biomedical research. The role of stem cells in this context is under intense scrutiny and may help to define principles of organ regeneration and develop innovative therapeutics for organ failure. Utilizing stem and progenitor cells for organ replacement has been conducted for many years when performing hematopoietic stem cell transplantation. Since the first successful transplantation of umbilical cord blood to treat hematological malignancies, non-hematopoietic stem and progenitor cell populations have recently been identified within umbilical cord blood and other perinatal and fetal tissues. A cell population entitled mesenchymal stromal cells (MSCs) emerged as one of the most intensely studied as it subsumes a variety of capacities: MSCs can differentiate into various subtypes of the mesodermal lineage, they secrete a large array of trophic factors suitable of recruiting endogenous repair processes and they are immunomodulatory.Focusing on perinatal tissues to isolate MSCs, we will discuss some of the challenges associated with these cell types concentrating on concepts of isolation and expansion, the comparison with cells derived from other tissue sources, regarding phenotype and differentiation capacity and finally their therapeutic potential.

Comparison of viscoelasticity between normal human sciatic nerve and amniotic membrane

Sciatic nerve tissue was obtained from the gluteus maximus muscle segment of normal human cadavers and amniotic membrane tissue was obtained from healthy human puerperant placentas. Both tissues were analyzed for their stress relaxation and creep properties to determine suitability for transplantation applications. Human amniotic membrane and sciatic nerve tissues had similar tendencies for stress relaxation and creep properties. The stress value of the amniotic membrane stress relaxation group decreased to a greater extent compared with the sciatic nerve stress relaxation group. Similarly, the stress value of the amniotic membrane creep group increased to a greater extent compared with the sciatic nerve creep group. The stress relaxation curve for human amniotic membrane and sciatic nerve showed a logarithm correlation, while the creep curve showed an exponential correlation. These data indicate that amniotic membrane tissue has better stress relaxation and creep properties compared with sciatic nerve tissue.

Platelet rich fibrin is not a barrier membrane!Or is it?

Platelet-rich fibrin(PRF)is widely used in dentistry and other fields of medicine,and its use has become popular in dental implantology.In several published studies,PRF has been used as a barrier membrane.A barrier membrane is a sheet of a certain material that acts as a biological and mechanical barrier against the invasion of cells that are not involved in bone formation,such as epithelial cells.Among the basic requirements of a'barrier membrane,occlusivity,stiffness,and space maintenance are the criteria that PRF primarily lacks;therefore,it does not fall under the category of barrier membranes.However,there is evidence that PRF membranes are useful in significantly improving wound healing.Does the PRF membrane act as a barrier?Should we think of adding or subtracting some points from the ideal requirements of a barrier membrane,or should we coin a new term or concept for PRF that will incorporate some features of a barrier membrane and be a combination of tissue engineering and biotechnology?This review is aimed at answering the basic question of whether the PRF membrane should be considered a barrier membrane or whether it is something more beyond the boundaries of a barrier membrane.

Membranes for the life sciences and their future roles in medicine

Since the global outbreak of COVID-19,membrane technology for clinical treatments,including extracorporeal membrane oxygenation(ECMO)and protective masks and clothing,has attracted intense research attention for its irreplaceable abilities.Membrane research and applications are now playing an increasingly important role in various fields of life science.In addition to intrinsic properties such as size sieving,dissolution and diffusion,membranes are often endowed with additional functions as cell scaffolds,catalysts or sensors to satisfy the specific requirements of different clinical applications.In this review,we will introduce and discuss state-of-the-art membranes and their respective functions in four typical areas of life science:artificial organs,tissue engineering,in vitro blood diagnosis and medical support.Emphasis will be given to the description of certain specific functions required of membranes in each field to provide guidance for the selection and fabrication of the membrane material.The advantages and disadvantages of these membranes have been compared to indicate further development directions for different clinical applications.Finally,we propose challenges and outlooks for future development.

A Novel Twist Deformation Model of Soft Tissue in Surgery Simulation

Real-time performance and accuracy are two most challenging requirements in virtual surgery training.These difficulties limit the promotion of advanced models in virtual surgery,including many geometric and physical models.This paper proposes a physical model of virtual soft tissue,which is a twist model based on the Kriging interpolation and membrane analogy.The proposed model can quickly locate spatial position through Kriging interpolation method and accurately compute the force change on the soft tissue through membrane analogy method.The virtual surgery simulation system is built with a PHANTOM OMNI haptic interaction device to simulate the torsion of virtual stomach and arm,and further verifies the real-time performance and simulation accuracy of the proposed model.The experimental results show that the proposed soft tissue model has high speed and accuracy,realistic deformation,and reliable haptic feedback.

Research and Application Progress of Silk Fibroin Membranes

This paper mainly introduced the preparation of silk fibroin membranes and their structural change characteristics.Silk fibroin membranes can be used as tissue engineering materials,enzyme-immobilizing membranes,biosensors and drug controlled-release membranes and other different materials.They have excellent characteristics such as non-toxic,non-polluting and degradable,and thus have broad application prospects.

Evaluation of corneal cell growth on tissue engineering materials as artificial cornea scaffolds

The keratoprosthesis(KPro;artificial cornea)is a special refractive device to replace human cornea by using heterogeneous forming materials for the implantation into the damaged eyes in order to obtain a certain vision.The main problems of artificial cornea are the biocompatibility and stability of the tissue particularly in penetrating keratoplasty.The current studies of tissue-engineered scaffold materials through comprising composites of natural and synthetic biopolymers together have developed a new way to artificial cornea.Although a wide agreement that the long-term stability of these devices would be greatly improved by the presence of cornea cells,modification of keratoprosthesis to support cornea cells remains elusive.Most of the studies on corneal substrate materials and surface modification of composites have tried to improve the growth and biocompatibility of cornea cells which can not only reduce the stimulus of heterogeneous materials,but also more importantly continuous and stable cornea cells can prevent the destruction of collagenase.The necrosis of stroma and spontaneous extrusion of the device,allow for maintenance of a precorneal tear layer,and play the role of ensuring a good optical surface and resisting bacterial infection.As a result,improvement in corneal cells has been the main aim of several recent investigations;some effort has focused on biomaterial for its well biological properties such as promoting the growth of cornea cells.The purpose of this review is to summary the growth status of the corneal cells after the implantation of several artificial corneas.

In vitro reconstruction and characterization of tissue-engineered human corneal epithelium with seeder cells from an untransfected human corneal epithelial cell line

AIM: To demonstrate the morphology and structure of in vitro reconstructed tissue-engineered human corneal epithelium (TE-HCEP) with seeder cells from an untransfected HCEP cell line. METHODS: The TE-HCEPs were reconstructed in vitro with seeder cells from an untransfected HCEP cell line, and scaffold carriers of denuded amniotic membrane (dAM) in air-liquid interface culture for 3, 5, 7 and 9 days, respectively. The specimens were examined with hematoxylin-eosin (HE) staining of paraffin-section, immunocytochemical staining, scanning and transmission electron microscopy. RESULTS: During in vitro reconstruction of TE-HCEP, HCEP cells formed a 3-4, 6-7 and 8-10 layers of an HCEP-like structure on dAMs in air-liquid interface culture for 3, 5 and 7 days, respectively. But the cells deceased to 5-6 layers and the structure of straified epithelium became loose at day 9. And the cells maintained positive expression of marker proteins (keratin 3 and keratin 12), cell-junction proteins (zonula occludens-1, E-cadherin, connexin 43 and integrin beta 1) and membrane transport protein of Na+-K+ ATPase. The HCEP cells in TE-HCEP were rich in microvilli on apical surface and established numerous cell-cell and cell-dAM junctions at day 5. CONCLUSION: The morphology and structure of the reconstructed TE-HCEP were similar to those of HCEP in vivo. The HCEP cells in the reconstructed TE-HCEP maintained the properties of HCEP cells, including abilities of forming intercellular and cell-extracellular matrix junctions and abilities of performing membrane transportation. The untransfected HCEP cells and dAMs could promisingly be used in reconstruction HCEP equivalent for clinical corneal epithelium transplantation.

Amniotic membrane covering for facial nerve repair

Amniotic membranes have been widely used in ophthalmology and skin injury repair because of their anti-inflammatory properties. In this study, we measured therapeutic efficacy and determined if amniotic membranes could be used for facial nerve repair. The facial nerves of eight rats were dissected and end-to-end anastomosis was performed. Amniotic membranes were covered on the anastomosis sites in four rats. Electromyography results showed that, at the end of the 3rd and 8th weeks after amniotic membrane covering, the latency values of the facial nerves covered by amniotic membranes were significantly shortened and the amplitude values were significantly increased. Compared with simple facial nerve anastomosis, after histopathological examination, facial nerve anastomosed with amniotic membrane showed better continuity, milder inflammatory reactions, and more satisfactory nerve conduction. These findings suggest that amniotic membrane covering has great potential in facial nerve repair.

Transplantation of tissue-engineered human corneal epithelium in limbal stem cell deficiency rabbit models

AIM: To evaluate the biological functions of tissue-engineered human corneal epithelium (TE-HCEP) by corneal transplantation in limbal stem cell deficiency (LSCD) rabbit models. METHODS: TE-HCEPs were reconstructed with DiI-labeled untransfected HCEP cells and denuded amniotic membrane (dAM) in air-liquid interface culture, and their morphology and structure were characterized by hematoxylin-eosin (HE) staining of paraffin-sections, immunohistochemistry and electron microscopy. LSCD models were established by mechanical and alcohol treatment of the left eyes of New Zealand white rabbits, and their eyes were transplanted with TE-HCEPs with dAM surface outside by lamellar keratoplasty (LKP). Corneal transparency, neovascularization, thickness, and epithelial integrality of both traumatic and post transplantation eyes were checked once a week by slit-lamp corneal microscopy, a corneal pachymeter, and periodic acid-Schiff (PAS) staining. At day 120 post surgery, the rabbits in each group were sacrificed and their corneas were examined by DiI label observation, HE staining, immunohistochemistry and electron microscopy. RESULTS: After cultured for 5 days on dAM, HCEP cells, maintaining keratin 3 expression, reconstructed a 6-7 layer TE-HCEP with normal morphology and structure. The traumatic rabbit corneas, entirely opaque, conjunctivalized and with invaded blood vessels, were used as LSCD models for TE-HCEP transplantation. After transplantation, obvious edema was not found in TE-HCEP-transplanted corneas which became more and more transparent, the invaded blood vessels reduced gradually throughout the monitoring period. The corneas decreased to normal thickness on day 25, while those of dAM eyes were over 575 mu m in thickness during the monitoring period. A 45 layer of epithelium consisting of TE-HCEP originated cells attached tightly to the anterior surface of stroma was reconstructed 120 days after TE-HCEP transplantation, which was similar to the normal control eye in morphology and structure. In contrast, intense corneal edema, turbid, invaded blood vessels were found in dAM eyes, and no multilayer epithelium was found but only a few scattered conjunctiva-like cells appeared. CONCLUSION: The TE-HCEP, with similar morphology and structure to those of innate HCEP, could reconstruct a multilayer corneal epithelium with normal functions in restoring corneal transparency and thickness of LSCD rabbits after transplantation. It may be a promising HCEP equivalent for clinical therapy of corneal epithelial disorders.

Acellular Amniotic Membrane Patch Regeneration for Burn Injury: The Future for Wound Healing

Acellular amniotic membrane (AAM) is a biodegradable and biocompatible natural that has a wide range of applications in the field of pharmaceutics, biomedical, chemical and cosmetics industry. One of the most interesting characteristics of AAM is its antibacterial and anti-inflammatory, anti-angiogenic, anti-fibrosis activity is an attractive approach for treating inflammatory disorders, wounds, and burns. The isolated use of AAM may not be sufficient to produce an adequate anti-inflammatory and antimicrobial effect to fulfill different purposes, has attracted considerable attention that has similar properties to the native tissues. This mini-review offers a focuses on modern aspects of the biomaterials, growth factors, biocompatibility, and acellular matrix which are the basic elements for use in the tissue regeneration and replacement after an injury.

Repair of Spontaneous Corneal Perforation in Pellucid Marginal Degeneration Using Amniotic Membrane

A 47-year-old woman with a history of pellucid marginal degeneration was referred for management of hydrops and peripheral perforation of the right cornea. The initial management with cyanoacrylate tissue adhesive and bandage contact lens did not preclude aqueous leakage the next day. Amniotic membrane grafting using both a surgical graft and a bandage patch was thus performed in the operating room the following day. There was no aqueous leakage on the first post-operative day. The corneal integrity was restored with resolution of the corneal edema;and the visual acuity improved from 20/400 before surgery to 20/40 three months later. This case illustrates the clinical efficacy of amniotic membrane grafting as an effective alternative in the management of spontaneous corneal perforation resulted from pellucid marginal degeneration.

Diabetes-related intestinal region-specific thickening of ganglionic basement membrane and regionally decreased matrix metalloproteinase 9 expression in myenteric ganglia

BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9(MMP9) and its tissue inhibitor(TIMP1) are essential in regulating extracellular matrix remodelling.AIM To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.METHODS Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex-and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Wholemount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid(m RNA) level was measured by quantitative polymerase chain reaction.RESULTS Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the m RNA levels.CONCLUSION These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.