Synthesis of PDMS Chain Structure with Introduced Dynamic Covalent Bonding for High-Performance Rehealable Tactile Sensor Application.

In addressing the increasing demand for wearable sensing systems, the performance and lifespan of such devices must be improved by enhancing their sensitivity and healing capabilities. The present work introduces an innovative method for synthesizing a healable disulfide bond contained in a polydimethylsiloxane network (PDMS-SS) that incorporates ionic salts, which is designed to serve as a highly effective dielectric layer for capacitive tactile sensors. Within the polymer network structure, the cross-linking agent pentaerythritol tetrakis 3-mercaptopropionate (PTKPM) forms reversible disulfide bonds while simultaneously increasing polymer softness and the dielectric constant. The incorporation of dioctyl sulfosuccinate sodium salt (DOSS) significantly improves the capacitance and sensing properties by forming an electrical double-layer through interactions between the electrode charge and salt ions at the contact interface. The developed polymer material-based tactile sensor shows a strong response signal at low pressure (0.1 kPa) and maintains high sensitivity (0.175 kPa-1) over a wide pressure range (0.1-10 kPa). It also maintains the same sensitivity over 10 000 repeated applications of external pressure and is easily self-healed against mechanical deformation due to the dynamic disulfide covalent bonding, restoring ≈95% of its detection capacity.

Structural Control of Nanofibers According to Electrospinning Process Conditions and Their Applications.

Nanofibers have gained much attention because of the large surface area they can provide. Thus, many fabrication methods that produce nanofiber materials have been proposed. Electrospinning is a spinning technique that can use an electric field to continuously and uniformly generate polymer and composite nanofibers. The structure of the electrospinning system can be modified, thus making changes to the structure, and also the alignment of nanofibers. Moreover, the nanofibers can also be treated, modifying the nanofiber structure. This paper thoroughly reviews the efforts to change the configuration of the electrospinning system and the effects of these configurations on the nanofibers. Excellent works in different fields of application that use electrospun nanofibers are also introduced. The studied materials functioned effectively in their application, thereby proving the potential for the future development of electrospinning nanofiber materials.

Effect of Blood Gel Derivatives on Wound Healing in Mouse Injured Tissue Models.

Several previous studies in the field of assisted reproduction have focused on the use of blood gel derivatives, such as platelet-rich fibrin (PRF), as a treatment for endometrial rehabilitation. However, the ability to release growth factors and the gel form of this product led to the evolution of platelet lysates. In this study, blood gel derivatives, including PRF lysate, which was in liquid form, and PRF gel, were collected and evaluated for growth factors. It was shown to be effective in endometrial wound healing and regeneration in mouse injured uterine tissue models through structure and function (pinopode expression, embryo implantation) evaluation. The results demonstrated that the concentrations of growth factors, including PDGF-AB and VEGF-A, were higher in the PRF lysate compared to the PRF gel (p < 0.05). PRF lysate could release these growth factors for 8 days. Furthermore, both PRF gel and PRF lysate restored the morphology of injured endometrial tissues in terms of luminal and glandular epithelia, as well as uterine gland secretory activity. However, the presence of pinopodes and embryonic implantation were only observed in the PRF lysate group. It can be concluded that PRF lysate promotes wound healing in mouse injured tissue models in vitro, which can act as healing products in tissue repair.

In-Vitro Endothelialization Assessment of Heparinized Bovine Pericardial Scaffold for Cardiovascular Application.

(1) Background: Hemocompatibility is a critical challenge for tissue-derived biomaterial when directly contacting the bloodstream. In addition to surface modification with heparin, endothelialization of the grafted material is suggested to improve long-term clinical efficacy. This study aimed to evaluate the ability to endothelialize in vitro of heparinized bovine pericardial scaffolds. (2) Methods: bovine pericardial scaffolds were fabricated and heparinized using a layer-by-layer assembly technique. The heparinized scaffolds were characterized for heparin content, surface morphology, and blood compatibility. Liquid extraction of the samples was prepared for cytotoxicity testing on human endothelial cells. The in-vitro endothelialization was determined via human endothelial cell attachment and proliferation on the scaffold. (3) Results: The heparinized bovine pericardial scaffold exhibited a heparin coating within its microfiber network. The scaffold surface immobilized with heparin performed good anti-thrombosis and prevented platelet adherence. The proper cytotoxicity impact was observed for a freshly used heparinized sample. After 24 h washing in PBS 1X, the cell compatibility of the heparinized scaffolds was improved. In-vitro examination results exhibited human endothelial cell attachment and proliferation for 7 days of culture. (4) Conclusions: Our in-vitro analysis provided evidence for the scaffold's ability to support endothelialization, which benefits long-term thromboresistance.

Decellularization of Bone Tissue.

Decellularization technology is a process that uses different methods such as physical, chemical or enzymatic methods in order to eliminate cellular remnants from original tissues or organs while minimizing any adverse effect on the structural properties, biological activity, and mechanical integrity of the remaining ECM. Regenerative medicine uses the most promising therapies to replace or regenerate tissues and organs in human, restore or establish normal functions lost due to disease or injury. By the combination between new biomaterials and cells, one of the goals of regenerative medicine is to create autologous grafts for transplantation therapies in the future.Various decellularization methods have been developed include chemical treatment, biological treatment and physical treatment. The aim of this chapter is to evaluate the decellularization method and all available materials that preserves the matrix without structural disruption.

In vitro study on chondrogenic differentiation of human adipose-derived stem cells on treated bovine pericardium.

Bovine pericardium has been proposed as an available material for tissue engineering and bioprosthetic reconstruction. In this study, bovine pericardium was fabricated into a scaffold for culturing and chondrogenic differentiation of human adipose-derived stem cells (hADSCs). Bovine pericardium was treated in 10 mM Tris-HCl and 0.15% SDS, followed by crosslinking in 0.1% glutaraldehyde. Treated bovine pericardium (tBP) was characterized as a slight yellowish thin membrane with enhanced tensile strength and strain property. The membrane maintained stability under enzymatic conditions for up to 16 days of incubation. The results confirmed tBP as a cell-friendly scaffold for hADSCs due to low cytotoxicity and its ability to support an appropriate attachment and proliferation of hADSCs. Moreover, there was an accumulation of the extracellular matrix proteoglycan in tBP seeded with hADSCs after 7 and 14 days of chondrogenic induction. COMP as a specific marker of chondrogenesis was detected after 7 days, whereas type X-a1 collagen (Col10a1) expression was stable up to day 14. However, minor expression of aggrecan was found. Taken together, these results indicate that tBP is a potential scaffold for hADSCs for cartilage tissue engineering.Key words: Bovine pericardium, scaffold, adipose-derived stem cells, chondrogenic differentiation, cartilage regeneration, augmentation rhinoplasty.

Effect of Modified Bovine Pericardium on Human Gingival Fibroblasts in vitro.

Supportive membranes have recently been applied to treat periodontal disease in order to achieve periodontal tissue regeneration. The crucial role of these membranes is to facilitate the restoration of the structural and functional periodontium. Bovine pericardium (BP) is mainly composed of collagen type I, which was demonstrated to have good mechanical properties and biological regenerative potential. Our research aimed to extend the application of membrane derived from BP to periodontal disease treatment. However, the fabrication method to achieve a xenogenic-free membrane with the mechanical properties required for periodontal treatment is rarely mentioned. Therefore, a procedure for the extraction and modification of BP using sodium dodecyl sulfate (SDS) and glutaraldehyde (GA) was developed. BP was harvested and decellularized using different SDS concentrations (0.05-0.3%). GA was used to further modify the membranes to achieve suitable thickness, mechanical strength, and pore size. A combination protocol of 0.15% SDS treatment for 12 h with continuous agitation combined with 0.1% GA for 6 h for membrane fabricating was applied. The modified BP (mBP) had the targeted characteristics, such as 0.2-0.5 mm thickness, approximately 10 MPa in tensile strength, 30% in strain force, and a pore size <5 µm, which is comparable to commercially available collagen membranes. Findings from this study demonstrated that the established method was effective in preparing BP membrane for periodontal treatment while decreasing the concentration of reagents and processing time. Moreover, our modified membrane was found to have no cytotoxicity but supports the migration, attachment, and proliferation of human gingival fibroblasts in vitro. Taken together, these results confirmed that mBP is suitable for application in periodontal disease treatment and regeneration.