EMEMI: An interference-free mini-incubator with integrated electric and magnetic field exposure for real-time microscopic imaging of field effects.

Uninterrupted microscopic observation and real-time imaging of cell behavior during exposure to the stimulus, for example, electric and/or magnetic fields, especially for periods of several days, has been a challenge in experimental bioelectromagnetics due to a lack of proper gas/temperature conditions outside the incubator. Conventional mini-incubators might suffer from stray fields produced by heating elements. We report an in vitro electric and magnetic fields (EMF) exposure system embedded inside a novel under-the-microscope mini-CO2 -incubator with a unique design to avoid electromagnetic interference from the heating and circulation functions while ensuring the requisite temperature. A unique, reconfigurable array of electrodes and/or coils excited by calculated current distributions among array elements is designed to provide excellent field uniformity and controllable linear or circular polarization (even at very low frequencies) of the EMF within the cell culture. Using standard biochemical assays, long-term cell viability has been verified and compared with a conventional incubator. Cell orientation/migration in three-dimensional culture made of collagen-hydrogels has been successfully observed in vitro, in long-term, and in real-time under the influence of DC electric fields with the device.

A review of accelerated wound healing approaches: biomaterial- assisted tissue remodeling.

Nowadays, due to a growing number of tissue injuries, in particular, skin wounds, induction and promotion of tissue healing responses can be considered as a crucial step towards a complete regeneration. Recently, biomaterial design has been oriented towards promoting a powerful, effective, and successful healing. Biomaterials with wound management abilities have been developed for different applications such as providing a native microenvironment and supportive matrices that induce the growth of tissue, creating physical obstacles against microbial contamination, and to be used as delivery systems for therapeutic reagents. Until now, numerous strategies aiming to accelerate the wound healing process have been utilized and studied with their own pros and cons. In this review, tissue remodeling phenomena, wound healing mechanisms, and their related factors will be discussed. In addition, different methods for induction and acceleration of healing via cell therapy, bioactive therapeutic delivery, and/or biomaterial-based approaches will be reviewed.

Synthesis and characterization of an octaarginine functionalized graphene oxide nano-carrier for gene delivery applications.

The success of gene therapy is largely dependent on the development of a gene carrier. Recently cell-penetrating peptides (CPPs) have been employed for enhancing the gene and drug delivery efficacy of nano-particles. The feasibility of octaarginine (R8) functionalized graphene oxide (GO) as a novel nano-carrier for gene delivery is investigated. A DNA plasmid expressing enhanced green fluorescent protein (pEGFP) is used as a model gene to study the R8-GO transfection ability into mammalian cells. R8 peptide is conjugated in different ratios (0.1-1.5 µmol per mg of GO) to carboxylated graphene oxide by a two step amidation process. The process of peptide conjugation is analyzed by Fourier transform infrared (FTIR), atomic force microscopy (AFM), UV-vis spectroscopy and X-ray diffraction (XRD). In order to obtain the highest transfection of pEGFP into the cells, the amount of peptide bound to GO is optimized which is evidenced by dynamic light scattering (DLS), zeta potential, TNBS and gel retardation assays. The cytotoxicity of R8-functionalized GO is also tested by MTT assay. The results confirm the successful attachment of R8 peptide to GO. The AFM and XRD results show a significant increase in the thickness of nano graphene oxide sheets (NGOS) from 0.8 to 2-7 nm as well as an increase in the GO interlying space after the R8-functionalization process. A reduction in nano-carrier stability in both aqueous solution and cell culture media is observed when the amount of peptide is increased to more than 1 µmol mg(-1). Gel electrophoresis analysis shows the highest DNA loading on the peptide functionalized GO at the ratios of 0.5 and 1 µmol mg(-1). As a result, the conjugated peptide sample with a peptide molar ratio of 1 µmol per mg of GO shows the highest conjugational efficiency and EGFP gene expression along with improved dispersibility and biocompatibility. Overall, the findings reveal the importance of peptide density on the surface of NGOS in order to obtain the most efficient cell transfection. It is concluded that the R8-conjugated GO could be a promising nano-carrier for gene delivery with relevance in biotechnology therapeutics and clinical applications.

Highly Absorbent Egg White/Carbomer-940 Hydrofilm as a Potential Diabetic Wound Dressing.

Diabetic foot ulcer (DFU) is the most critical problem in diabetic patients. Managing exudate in this kind of wound presents significant challenges in clinics. Advanced wound dressings serve as the most effective approach to managing DFU. Herein, a highly absorbent hydrofilm is presented through a combination of egg white (EW) and Carbomer-940, benefiting from the bioactivity of the EW component and superabsorption capacity of Carbomer-940. The crystallinity of samples rises due to the presence of Carbomer-940. Regarding the high water absorption capacity of Carbomer-940, the swelling ratio and water-holding capacity of samples are also improved via its incorporation of up to 1005%. In contrast, the transmission of water vapor and in vitro degradation rate decreases as Carbomer-940 powers the crystallinity of hydrofilms. Carbomer-940 incorporation in the EW structure accelerates protein release during the time, while this acceleration is partially compensated by the crystallization effect. The cell viability assay demonstrates no toxicity as well as high human foreskin fibroblast cell proliferation for the hybrid hydrofilm sample, where the cell migration is positively affected in the presence of the bioactive components extracted from the dressing. Taken together, the optimized hybrid hydrofilm could be suggested as a promising wound dressing for managing DFUs.

Augmented physical, mechanical, and cellular responsiveness of gelatin-aldehyde modified xanthan hydrogel through incorporation of silicon nanoparticles for bone tissue engineering.

Bioactive scaffolds fabricated from a combination of organic and inorganic biomaterials are a promising approach for addressing defects in bone tissue engineering. In the present study, a self-crosslinked nanocomposite hydrogel, composed of gelatin/aldehyde-modified xanthan (Gel-AXG) is successfully developed by varying concentrations of porous silicon nanoparticles (PSiNPs). The effect of PSiNPs incorporation on physical, mechanical, and biological performance of the nanocomposite hydrogel is evaluated. Morphological analysis reveals formation of highly porous 3D microstructures with interconnected pores in all nanocomposite hydrogels. Increased content of PSiNPs results in a lower swelling ratio, reduced porosity and pore size, which in turn impeded media penetration and slowed down the degradation process. In addition, remarkable enhancements in dynamic mechanical properties are observed in Gel-AXG-8%Si (compressive strength: 0.6223 MPa at 90 % strain and compressive modulus: 0.054 MPa), along with improved biomineralization ability via hydroxyapatite formation after immersion in simulated body fluid (SBF). This optimized nanocomposite hydrogel provides a sustained release of Si ions at safe dose levels. Furthermore, in-vitro cytocompatibility studies using MG-63 cells exhibited remarkable performance in terms of cell attachment, proliferation, and ALP activity for Gel-AXG-8%Si. These findings suggest that the prepared nanocomposite hydrogel holds promising potential as a scaffold for bone tissue engineering.

Corneal sustained delivery of hyaluronic acid from nanofiber-containing ring-implanted contact lens.

Dry eye syndrome, as a persist corneal epithelial defect (PED), is an inconvenient ocular disorder that is generally treated by high-dosage, conventional eye drops. Addressing low efficacy and rather restricted bioavailability of the conventional eye drops, drug-eluting contact lenses (CLs) are widely used as alternatives in ophthalmic drug delivery applications. In the present study, a nanofiber-containing ring implant poly (vinyl alcohol) (PVA) hydrogel is designed as a carrier for hyaluronic acid (HA) delivery. hyaluronic acid is physically encapsulated in a nanofiber-containing ring-shaped hydrogel with a 2 mm width that is implanted in the final CLs hydrogel. The designed CL has 59% porosity, 275% swelling ratio and undergoes no weight loss at physiological conditions in14 days. In-vitro release studies were performed on the CLs with and without nanofibers. The results showed that nanofiber incorporation in the designed CL was highly influential in decreasing burst release and supported sustained release of HA over 14 days. In addition, nanofiber incorporation in the designed system strengthened the lens, and the young modulus of the PVA hydrogel increased from 6 to 10 kPa. Cell viability study also revealed no cell cytotoxicity and cell attachment. Overall, the study demonstrated the effective role of nanofibers in the physical strengthening of the CL. Also, the designed system holds promise as a potential candidate for HA delivery over an extended period for treating dry eye syndrome.

Poly (l-lactic acid)-based modified nanofibrous membrane with dual drug release capability for GBR application.

Electrospun multilayer nanofibers guided bone regeneration (GBR) with a new design were developed in this study. The synthesized multilayer GBR was composed of two distinct layers. Poly l-lactic acid (PLA) incorporated with simvastatin (SIM) was designed as PLA/SIM layer to contact with a bone defect. In addition, the hydrophilic gelatin (GT) containing thymol (THY) was fabricated as GT/THY layer to contact connective tissue, potentially for bacterial gathering. Due to the different chemical nature and weak cohesion of the hydrophilic and hydrophobic layers, hybrid fibers made of PLA/SIM and GT/THY were electrospun as cohesion promoters between these layers. The microstructure and characteristics of the synthesized multilayer substrate, named GT/PLA, were evaluated, and different fibrous monolayers were fabricated to determine the optimal concentrations of drugs. Scanning electron microscopy (SEM) images showed continuous, smooth, randomly aligned, and bead-free fibers. In addition, there were no drug particles on the fiber surfaces which displayed the good placement of those inside the fibers. The mats exhibited satisfactory tensile strength (4.60 ± 0.14 MPa) and favorable physicochemical properties, including proper porosity percentage (<50 %) and appropriate pore size. Suitable swelling behavior (293 ± 0.05 %) and adequate degradation rates were also approved by characterizing swelling and degradability in vitro. The GT/PLA membrane exhibited a prolonged and sustained SIM release and controlled THY release with high antibacterial efficiency. Cell viability, cell attachment assay, and nuclear staining using 4',6-diamidino-2-phenylindole (DAPI) showed that the designed GT/PLA substrate had good biocompatibility and cell attachment. Cell infiltration testing also showed that the cells were finely prevented by the outer layer (GT/THY). Overall, the obtained results in this study indicated the great potential of the prepared GT/PLA for use as a GBR which can develop osteogenic and antibacterial biomimetic periosteum optimizing the clinical application of GBR strategies.

Angiogenesis induction as a key step in cardiac tissue Regeneration: From angiogenic agents to biomaterials.

Cardiovascular diseases are the leading cause of death worldwide. After myocardial infarction, the vascular supply of the heart is damaged or blocked, leading to the formation of scar tissue, followed by several cardiac dysfunctions or even death. In this regard, induction of angiogenesis is considered as a vital process for supplying nutrients and oxygen to the cells in cardiac tissue engineering. The current review aims to summarize different approaches of angiogenesis induction for effective cardiac tissue repair. Accordingly, a comprehensive classification of induction of pro-angiogenic signaling pathways through using engineered biomaterials, drugs, angiogenic factors, as well as combinatorial approaches is introduced as a potential platform for cardiac regeneration application. The angiogenic induction for cardiac repair can enhance patient treatment outcomes and generate economic prospects for the biomedical industry. The development and commercialization of angiogenesis methods often involves collaboration between academic institutions, research organizations, and biomedical companies.

Synthesis and Characterization of Thymol-Loaded Niosomal Film for the Prevention of Implant-Related Infection.

Background: Infection is one of the significant challenges in medical implant-related surgeries. Despite systemic antibiotic therapies, bacterial growth after implantation may cause implant failure. Nowadays, unlike the systemic therapy, local controlled release of antibiotic agents is considered an effective approach for the prevention of implant-related infections. The present study aimed to develop a niosomal nanocarrier incorporated into fibroin films for local and continuous delivery of thymol, a natural plant-derived antimicrobial agent for preventing infections caused by implant-related. Methods: Niosomes containing thymol were prepared by thin-film hydration technique. Thymol sustained release from the prepared films was assessed for 14 days. Antibacterial activities of the synthesized films were also evaluated by the agar diffusion technique against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Results: The release behavior from the niosomal thymol films showed a sustained manner, in which the amount of the released thymol reached 40% after 14 days. The films containing thymol with and without niosome showed a significant viability against L929 fibroblast cells compared to other groups after 24 and 48 h, using MTT assay. Also, samples exhibited potent antibacterial activity against Gram-negative and Gram-positive bacteria. Conclusion: The results of this study demonstrate that the niosomal thymol-loaded fibroin film is a promising candidate for the controlled release of thymol and prevention of implant-related infection.

Potential of graphene-based nanomaterials for cardiac tissue engineering.

Cardiovascular diseases are the primary cause of death worldwide. Despite significant advances in pharmacological treatments and surgical interventions to restore heart function after myocardial infarction, it can progress to heart failure due to the restricted inherent potential of adult cardiomyocytes to self-regenerate. Hence, the evolution of new therapeutic methods is critical. Nowadays, novel approaches in tissue engineering have assisted in restoring biological and physical specifications of the injured myocardium and, hence, cardiac function. The incorporation of a supporting matrix that could mechanically and electronically support the heart tissue and stimulate the cells to proliferate and regenerate will be advantageous. Electroconductive nanomaterials can facilitate intracellular communication and aid synchronous contraction via electroactive substrate creation, preventing the issue of arrhythmia in the heart. Among a wide range of electroconductive materials, graphene-based nanomaterials (GBNs) are promising for cardiac tissue engineering (CTE) due to their outstanding features including high mechanical strength, angiogenesis, antibacterial and antioxidant properties, low cost, and scalable fabrication. In the present review, we discuss the effect of applying GBNs on angiogenesis, proliferation, and differentiation of implanted stem cells, their antibacterial and antioxidant properties, and their role in improving the electrical and mechanical properties of the scaffolds for CTE. Also, we summarize the recent research that has applied GBNs in CTE. Finally, we present a concise discussion on the challenges and prospects.

Multimodal effects of asymmetric coating of coronary stents by electrospinning and electrophoretic deposition.

Drug-eluting stents (DESs) are drug-coated vascular implants that inhibit smooth muscle cell proliferation and limit in-stent re-stenosis. However, traditional DESs release a single drug into the blood and cannot cope with complex mechanisms in atherosclerosis and body responses. The present study aimed to develop a novel multimodal stent by fabricating asymmetric coating with electrophoretic deposition and electrospinning. Herein, we use heparin-loaded alginate (Hep/Alg) and atorvastatin calcium-loaded polyurethane (AtvCa/PU) coatings on the stent luminal and abluminal surfaces, respectively. Scanning electron microscopy (SEM) micrographs showed that the alginate coatings had uniformity and thin thickness. Meanwhile, the PU fibers were formed without beads, with an acceptable diameter and suitable mechanical properties. PU nanofiber revealed minimal degradation in a 1-month study. The release of AtvCa and Hep continued for 8 days without a significant initial burst release. None of the stent coatings were cytotoxic or hemolytic, and PU nanofibers supported the survival of human umbilical endothelial cells (HUVEC) with high adhesion and flattened morphologies. The results indicate that electrophoretic deposition and electrospinning have significant potential for achieving asymmetric coating on stents and a promising approach for dual drug release for multimodal effects in vascular stent applications.

Optimization and comparison of two different 3D culture methods to prepare cell aggregates as a bioink for organ printing.

The ultimate goal of tissue engineering is to design and fabricate functional human tissues that are similar to natural cells and are capable of regeneration. Preparation of cell aggregates is one of the important steps in 3D tissue engineering technology, particularly in organ printing. Two simple methods, hanging drop (HD) and conical tube (CT) were utilized to prepare cell aggregates. The size and viability of the aggregates obtained at different initial cell densities and pre-culture duration were compared. The proliferative ability of the cell aggregates and their ability to spread in culture plates were also investigated. In both methods, the optimum average size of the aggregates was less than 500 microm. CT aggregates were smaller than HD aggregates. 5,000 cells per drop HD aggregates showed a marked ability to attach and spread on the culture surface. The proliferative ability reduced when the initial cell density was increased. Comparing these methods, we found that the HD method having better size controlling ability as well as enhanced ability to maintain higher rates of viability, spreading, and proliferation. In conclusion, smaller HD aggregates might be a suitable choice as building blocks for making bioink particles in bioprinting technique.

Effect of electrochemical oxidation and drug loading on the antibacterial properties and cell biocompatibility of titanium substrates.

A combination of [Formula: see text] nanotube array (TON) and controlled drug release system is employed to provide enhanced surface properties of titanium implants. Electrochemical anodization process is used to generate TON for introducing, vancomycin, an effective antibacterial drug against Staphylococcus aureus. TON loaded vancomycin is then coated with a number of layers of 10% gelatin using spin coating technique. The gelatin film is reinforced with graphene oxide (GO) nanoparticles to improve the surface bioactivity. The surface of the samples is characterized by field emission electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and contact angle measurement. The results illustrate that the TON was constructed and vancomycin molecules are successfully loaded. The drug release study shows that the amount of released vancomycin is controlled by the thickness of gelatin layers. With an increase in gelatin film layers from 3 to 7, the release of vancomycin in the burst release phase decreased from 58 to 31%, and sustained release extended from 10 to 17 days. The addition of GO nanoparticles seems to reduce drug release in from 31 to 22% (burst release phase) and prolonged drug release (from 17 to 19 days). MTT assay indicates that samples show no cytotoxicity, and combination of GO nanoparticles with gelatin coating could highly promote MG63 cell proliferation. Soaking the samples in SBF solution after 3 and 7 days demonstrates that hydroxy apatite crystals were deposited on the TON surface with GO-gelatin coating more than surface of TON with gelatin. Moreover, based on the results of disc diffusion assay, both samples (loaded with Vancomycin and coated with gelatin and gelatin-GO) with the inhibition zones equaled to 20 mm show effective antibacterial properties against S. aureus. The evidence demonstrates that titania nanotube loaded with vancomycin and coated with gelatin-GO has a great potential for general applicability to the orthopedic implant field.

Angiogenic Effect of a Nanoniosomal Deferoxamine-Loaded Poly(vinyl alcohol)-Egg White Film as a Promising Wound Dressing.

Owing to the noticeable increase in the number of patients with impaired wound healing capabilities, developing bioactive wound dressings with supportive physicomechanical and biological properties for clinical wound management has attracted much more attention nowadays. In this regard, engineered dressings with angiogenesis potential are vital for accelerated tissue regeneration. In the current study, nanoniosomal deferoxamine (DFO)-loaded transparent films of egg white-poly(vinyl alcohol) (PVA/EW/ND) were successfully fabricated at three different PVA/EW ratios (1:0, 1:1, and 1:1.5 wt/wt %) through the thin film hydration and solvent casting methods. The developed films' characterizations were carried out using scanning electron microscopy, Fourier transform infrared spectroscopy analysis, uniaxial tensile strength, water uptake, water vapor transmission rate, in vitro degradation, and drug release. The results demonstrated that the various weight ratios of PVA/EW have a significant effect on the microscopic morphology, equilibrium swelling, degradation, and mechanical properties of the films. The drug release profile exhibited a sustained release of DFO with controlled burst-lag phases resembling the Korsmeyer-Peppas pattern. The cytotoxicity and adhesion analysis using human dermal fibroblasts displays the biocompatibility of the developed PVA/EW/ND films and the formation of cellular colonies on the surface. The in vitro angiogenic capability of the developed films evaluated by the scratch wound assay and microbead-assisted tube formation study showed a significant increase in the rate of migration of human umbilical vein endothelial cells and in the number of tube-like structures. Therefore, the achieved results suggest that the presented PVA/EW/ND film has promising potential for effective wound healing applications.

Microencapsulated Multifunctionalized Graphene Oxide Equipped with Chloroquine for Efficient and Sustained siRNA Delivery.

A multifunctionalized graphene oxide (GO)-based carrier with conjugation of aminated-polyethylene glycol (PEG-diamine), octaarginine (R8), and folic acid (FA), which also contains chloroquine (CQ), a lysosomotropic agent, is introduced. The cellular uptake mechanisms and intracellular targeting of FA-functionalized nanocarriers are examined. The localized releases of CQ and siRNA intracellular delivery are evaluated. Microencapsulation of the nanocarrier complexed with genes in layer-by-layer coating of alginate microbeads is also investigated. The covalently coconjugated FA with PEG and R8 provides a stable formulation with increased cellular uptake compared to FA-free carrier. The CQ-equipped nanocarrier shows a 95% release of CQ at lysosomal pH. The localized release of the drug inside the lysosomes is verified which accelerates the cargo discharge into cytoplasm.

A biomimetic three-layered fibrin gel/PLLA nanofibers composite as a potential scaffold for articular cartilage tissue engineering application.

Developing an engineered scaffold inspired by structural features of healthy articular cartilage (AC) has attracted much attention. In this study, the design and fabrication of a three-layered fiber/hydrogel scaffold in which each layer replicates the organization of a pertinent layer of AC tissue is aimed. To this end, electrospun poly-L-lactic acid (PLLA) nanofibers are prepared and fragmented into nano/micro cylinders via aminolysis. Three-layers of the scaffold, a fibrin coated fibrous layer, a fibrin gel (FG) layer incorporating chopped fibers and a FG embedding cylindrical aligned fibrous mat perpendicular to articulating surface, respectively served as an upper, middle and bottom layers, are prepared. The layers' physicomechanical characteristics are comprehensively evaluated. Results show that optimized electrospinning set up results in the smallest fibers diameter of 367 ± 317 nm and successful aminolysis provides amine-functionalized chopped nanofibers with a mean length of 1.46 ± 0.9 µm. Static mechanical analysis of the layers demonstrates that tensile Young's modulus of the upper layer is 152 ± 17 MPa while compressive moduli of the middle and bottom layers are 9.8 ± 3.8 and 25.3 ± 5.2 KPa, respectively and the compressive modulus of three-layered scaffold is 13.7 ± 2.5 KPa. Assessing mechanical parameters under dynamic loading also shows that adding fibrous part in the composite scaffold layers enhances viscoelastic behavior of FG. Also, incorporation of 0.25% chopped fibers into the fibrin matrix notably enhances the equilibrium water content; however, it increasesin-vitroweigh loss rate from 6% to 10.5% during a seven-day period. Cytocompatibility analysis confirms that all layers possess acceptable cytocompatibility. In a conclusion, the designed three-layered composite structure successfully mimics the physicomechanical as well as microstructural features of AC and could be suggested as a potential scaffold for this tissue regeneration.

Study of injectable PNIPAAm hydrogels containing niosomal angiogenetic drug delivery system for potential cardiac tissue regeneration.

Nowadays, heart disease, especially myocardial infarction, is one of the most astoundingly unfortunate causes of mortality in the world. That is why special attention has been paid toward tissue engineering techniques for curing and regeneration of heart tissue. In this study, poly(N-isopropyl acrylamide) (PNIPAAm), a temperature-sensitive injectable hydrogel, was selected as a minimally invasive scaffold to accommodate, carry, and release of niosomal rosuvastatin to the inflicted area for inducing angiogenesis and thus accelerating the healing process. The characteristics of PNIPAAm were studied by scanning electron microscopy, rheology tests, and Fourier transform infrared spectroscopy. The properties of the niosomal rosuvastatin release system, including particle size distribution, zeta potential, encapsulation efficiency (EE), and drug release, were also studied. The results showed that niosomes (358 nm) had a drug EE of 78% and a loading capacity of 53%. The drug was sustainably released from the system up to about 54% in 5 d. Cellular studies showed no toxicity to the endothelial cell lines, and the niosomal drug with a concentration of 7.5 nM enhanced cell proliferation, and cell migration increased from 72% to 90% compared to the control sample. Therefore, the controlled-release of niosomal rosuvastatin enhanced angiogenesis in a dose-dependent manner. Taken together, these advantages suggest that PNIPAAm-based niosomal hydrogel provides a promising candidate as an angiogentic injectable scaffold for potential cardiac tissue regeneration.

An Overview of Engineered Hydrogel-Based Biomaterials for Improved ß-Cell Survival and Insulin Secretion.

Islet transplantation provides a promising strategy in treating type 1 diabetes as an autoimmune disease, in which damaged ß-cells are replaced with new islets in a minimally invasive procedure. Although islet transplantation avoids the complications associated with whole pancreas transplantations, its clinical applications maintain significant drawbacks, including long-term immunosuppression, a lack of compatible donors, and blood-mediated inflammatory responses. Biomaterial-assisted islet transplantation is an emerging technology that embeds desired cells into biomaterials, which are then directly transplanted into the patient, overcoming the aforementioned challenges. Among various biomaterials, hydrogels are the preferred biomaterial of choice in these transplants due to their ECM-like structure and tunable properties. This review aims to present a comprehensive overview of hydrogel-based biomaterials that are engineered for encapsulation of insulin-secreting cells, focusing on new hydrogel design and modification strategies to improve ß-cell viability, decrease inflammatory responses, and enhance insulin secretion. We will discuss the current status of clinical studies using therapeutic bioengineering hydrogels in insulin release and prospective approaches.

Preparation of Nanoparticle-Containing Ring-Implanted Poly(Vinyl Alcohol) Contact Lens for Sustained Release of Hyaluronic Acid.

Here, a novel ring-implanted poly vinyl alcohol (PVA) contact lens (CL) is fabricated and evaluated as a therapeutic CL with potential of sustained release of hyaluronic acid (HA). HA is loaded on chitosan (CS) nanoparticles (NPs) and then the HA-loaded NPs are dispersed in a ring shape PVA hydrogel which is implanted in the final PVA CL. Results show that HA is successfully loaded on NPs (520 ± 18 nm) with loading efficacy of 87% and loading capacity of 50%. The CL hydrogel has a 275% swelling ratio, no degradation during 14 days, 97% light transmittance, and desirable rheological stability under physiological shear force. The release data show a sustained release for HA from the ring implanted CL up to 14 days. The cellular study reveals no corneal epithelial cell cytotoxicity and cell attachment on the CL. The study demonstrates the successful application of the ring-implanted CL to sustain the delivery of HA for treating the dry eye syndrome.

Skin wound healing assisted by angiogenic targeted tissue engineering: A comprehensive review of bioengineered approaches.

Skin injuries and in particular, chronic wounds, are one of the major prevalent medical problems, worldwide. Due to the pivotal role of angiogenesis in tissue regeneration, impaired angiogenesis can cause several complications during the wound healing process and skin regeneration. Therefore, induction or promotion of angiogenesis can be considered as a promising approach to accelerate wound healing. This article presents a comprehensive overview of current and emerging angiogenesis induction methods applied in several studies for skin regeneration, which are classified into the cell, growth factor, scaffold, and biological/chemical compound-based strategies. In addition, the advantages and disadvantages of these angiogenic strategies along with related research examples are discussed in order to demonstrate their potential in the treatment of wounds.