Biocompatibility of Nanocomposites Used for Artificial Conjunctiva:In VivoExperiments

Characterization of Gold-Enhanced Titania: Boosting Cell Proliferation and Combating Bacterial Infestation

BACKGROUND

In this study an approach was made to efficaciously synthesize gold enhanced titania nanorods by electrospinning. This study aims to address effects of gold enhanced titania nanorods on muscle precursor cells. Additionally, implant related microbial infections are prime cause of various disastrous diseases. So, there is predictable demand for synthesis of novel materials with multifunctional adaptability.

METHODS

Herein, gold nanoparticles were attached on titania nanorods and described using many sophisticated procedures such as XRD, SEM, EDX and TEM. Antimicrobial studies were probed against Gram-negative Escherichia coli. C2C12 cell lines were exposed to various doses of as-prepared gold enhanced titania nanorods in order to test in vitro cytotoxicity and proliferation. Cell sustainability was assessed through Cell Counting Kit-8 assay at regular intervals. A phase-contrast microscope was used to examine morphology of exposed C2C12 cells and confocal laser scanning microscope was used to quantify cell viability.

RESULTS

The findings indicate that titania nanorods enhanced with gold exhibit superior antimicrobial efficacy compared to pure titania. Furthermore, newly synthesized gold-enhanced titania nanorods illustrate that cell viability follows a time and concentration dependent pattern.

CONCLUSION

Consequently, our study provides optimistic findings indicating that titania nanorods adorned with gold hold significant potential as foundational resource for developing forthcoming antimicrobial materials, suitable for applications both in medical and biomedical fields. This work also demonstrates that in addition to being extremely biocompatible, titania nanorods with gold embellishments may be used in a range of tissue engineering applications in very near future.

Design and development of dual drug-loaded nanofibrous inserts for ophthalmic sustained delivery of AMK and VAN: Pharmacokinetic study in rabbit's eye

Bacterial corneal keratitis is a damage to the corneal tissue that if not treated, can cause various complications like severe vision loss or even blindness. Combination therapy with two antibiotics which are effective against Gram-positive and Gram-negative bacteria offers sufficient broad-spectrum antibiotic coverage for the treatment of keratitis. Nanofibers can be a potential carrier in dual drug delivery due to their structural characteristics, specific surface area and high porosity. In order to achieve a sustained delivery of amikacin (AMK) and vancomycin (VAN), the current study designed, assessed, and compared nanofibrous inserts utilizing polyvinyl alcohol (PVA) and polycaprolactone (PCL) as biocompatible polymers. Electrospinning method was utilized to prepare two different formulations, PVA-VAN/AMK and PCL/PVA-VAN/AMK, with 351.8 ± 53.59 nm and 383.85 ± 49 nm diameters, respectively. The nanofibers were simply inserted in the cul-de-sac as a noninvasive approach for in vivo studies. The data obtained from the physicochemical and mechanical properties studies confirmed the suitability of the formulations. Antimicrobial investigations showed the antibacterial properties of synthesized nanofibers against Staphylococcus aureus and Pseudomonas aeruginosa. Both in vitro and animal studies demonstrated sustained drug release of the prepared nanofibers for 120 h. Based on the in vivo findings, the prepared nanofibers' AUC0-120 was found to be 20 to 31 times greater than the VAN and AMK solutions. Considering the results, the nanofibrous inserts can be utilized as an effective and safe system in drug delivery.

[Methods of surgical reconstruction of the conjunctiva]

Reconstruction of the conjunctiva is required for restoration of damaged ocular surface and is an essential part of that process. Traumas, chemical and thermal burns, multiple surgical intervention can seriously damage the integrity of conjunctival tissue and promote the growth of fibrous tissue, scarring of contractures and their shortening, as well as other complications such as trichiasis, erosion and ulcers on the cornea. When a larger area is affected, there may not be enough donor tissue to replace the defect, in which case the tissue grafts are required to be large enough. Modern modifications of surgical techniques and the continued development of tissue engineering, as well as advancements in stem cell research offer promising novel alternatives for solution of those problems. This article reviews the existing surgical methods of conjunctival reconstruction.

[Conjunctival reconstruction-State of the art of regenerative treatment forms beyond the limbus]

BACKGROUND

The demands on conjunctival replacement tissues are high: they need to be elastic, clinically compatible, surgically feasible and support goblet cell growth.

OBJECTIVE

This article provides an overview of currently applied conjunctival replacement tissues and those under investigation.

METHOD

Current publications on clinically applied conjunctival replacement tissues and substrates which are the subject of scientific research and those already tested in animal models are presented and discussed.

RESULTS

Replacement tissues in clinical use are autologous and allogenic conjunctiva, nasal and oral mucous membranes, amniotic membrane and decellularized tissues. Autologous conjunctiva shows good results but is not suitable for large defects due to limited availability. In these cases autologous nasal and oral mucous membranes can be used; however, success is limited in cases of autoimmune diseases. Amniotic membranes are frequently applied clinically but goblet cell growth is limited. Different decellularized tissues are used clinically and goblet cell growth was found in vivo. Robust comparative studies are not yet available. Biological matrices such as fibrin, collagen, elastin, gelatin or hyaluronate and synthetic tissues from the group of polyesters are being investigated in the laboratory and in animal models. These studies show good epithelialization and goblet cell growth in vivo.

CONCLUSION

Transplantation of conjunctiva, nasal and oral mucous membranes and amniotic membranes show satisfactory clinical results but exhibit individual weaknesses. Further studies in animal models and clinical settings are required to further evaluate the benefits of other matrices, such as cell-free tissues or other biological and synthetic matrices.

Anti-Inflammatory Fibronectin-AgNP for Regulation of Biological Performance and Endothelial Differentiation Ability of Mesenchymal Stem Cells

The engineering of vascular regeneration still involves barriers that need to be conquered. In the current study, a novel nanocomposite comprising of fibronectin (denoted as FN) and a small amount of silver nanoparticles (AgNP, ~15.1, ~30.2 or ~75.5 ppm) was developed and its biological function and biocompatibility in Wharton's jelly-derived mesenchymal stem cells (MSCs) and rat models was investigated. The surface morphology as well as chemical composition for pure FN and the FN-AgNP nanocomposites incorporating various amounts of AgNP were firstly characterized by atomic force microscopy (AFM), UV-Visible spectroscopy (UV-Vis), and Fourier-transform infrared spectroscopy (FTIR). Among the nanocomposites, FN-AgNP with 30.2 ppm silver nanoparticles demonstrated the best biocompatibility as assessed through intracellular ROS production, proliferation of MSCs, and monocytes activation. The expression levels of pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6, were also examined. FN-AgNP 30.2 ppm significantly inhibited pro-inflammatory cytokine expression compared to other materials, indicating superior performance of anti-immune response. Mechanistically, FN-AgNP 30.2 ppm significantly induced greater expression of vascular endothelial growth factor (VEGF) and stromal-cell derived factor-1 alpha (SDF-1α) and promoted the migration of MSCs through matrix metalloproteinase (MMP) signaling pathway. Besides, in vitro and in vivo studies indicated that FN-AgNP 30.2 ppm stimulated greater protein expressions of CD31 and von Willebrand Factor (vWF) as well as facilitated better endothelialization capacity than other materials. Furthermore, the histological tissue examination revealed the lowest capsule formation and collagen deposition in rat subcutaneous implantation of FN-AgNP 30.2 ppm. In conclusion, FN-AgNP nanocomposites may facilitate the migration and proliferation of MSCs, induce endothelial cell differentiation, and attenuate immune response. These finding also suggests that FN-AgNP may be a potential anti-inflammatory surface modification strategy for vascular biomaterials.

Biological tissues and components, and synthetic substrates for conjunctival cell transplantation

The conjunctiva is the largest component of the ocular surface. It can be damaged by various pathological processes leading to scarring, loss of tissue and dysfunction. Depending on the amount of damage, restoration of function may require a conjunctival graft. Numerous studies have investigated biological and synthetic substrates in the search for optimal conditions for the ex vivo culture of conjunctival epithelial cells that can be used as tissue grafts for transplantation. These substrates have advantages and disadvantages that are specific to the characteristics of each material; the development of an improved material remains a priority. This review is the second of a two-part review in The Ocular Surface. In the first review, the structure and function of the conjunctiva was evaluated with a focus on the extracellular matrix and the basement membrane, and biological and mechanical characteristics of the ideal substrate with recommendations for further studies. In this review the types of biological and synthetic substrates used for conjunctival transplantation are discussed including substrates based on the extracellular matrix. .

TiO2 nanorods via one-step electrospinning technique: a novel nanomatrix for mouse myoblasts adhesion and propagation

This study was aimed at the synthesis and characterization of novel Titania nanorods by sol-gel electrospinning technique. The physicochemical properties of the synthesized nanorods were determined by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD) pattern. To examine the in vitro cytotoxicity, mouse myoblast C2C12 cells were treated with different concentrations of as prepared TiO(2) nanorods and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of the cells attached with nanorods were examined by Bio-SEM. Cytotoxicity experiments indicated that the mouse myoblast cells could attach to the TiO(2) nanorods after being cultured. We observed that TiO(2) nanorods could support cell adhesion and growth and guide spreading behavior of myoblasts. We conclude that the electrospun TiO(2) nanorods scaffolds with unique morphology had excellent biocompatibility. Thus, the current work demonstrates that the as-synthesized TiO(2) nanorods represent a promising biomaterial to be exploited for various tissue engineering applications.

Preservation, sterilization and de-epithelialization of human amniotic membrane for use in ocular surface reconstruction

In the past 20 years, human amniotic membrane (AM) has become widely used as an ophthalmic surgical patch as well as a substrate for stem cell tissue equivalents for ocular surface reconstruction. AM reduces ocular surface scarring and inflammation, and enhances epithelialization. In addition, it shows limited immunogenicity and some anti-microbial properties. Before being applied clinically, the donor of AM is required to undergo a thorough health screening and the membrane has to undergo an accepted processing routine, which includes preservation, sterilization and de-epithelialization. There have been various articles describing methods in preserving, sterilizing and de-epithelializing AM. Each preparation technique has been reported to have differential effects on the physical and biological properties of the AM. Therefore, it is difficult to establish a standardized procedure. In this review, we discuss the present techniques and several novel, new approaches in the preparation of AM for use in ocular surface reconstruction, and their impact on AM structure and biological activity.