Narrow Results

The purpose of this investigation was to prepare and evaluate the feasibility and biocompatibility of a new composite as a large defect bone substitute. The new GTGG was mainly composed of tricalcium phosphate ceramic particles and glutaraldehyde crosslinked gelatin in which Gui-Lu-Jiao was added (a mixture of Cervi Colla Cornus and Colla Plastri Testudinis). In the in vitro study, rat's calvaria osteoblasts were used to study bone characteristics upon exposure to different concentrations of the Gui-Lu-Jiao solution. In the in vivo study, GTGG composites were implanted into the defects of calvarial bones in mature New Zealand rabbits to test their osteogenerative characteristics. As a result, we found that Gui-Lu-Jiao added to the culture could promote the proliferation of osteoblasts. In addition, GTGG could induce a large amount of new bone growth in the rabbit's calvarial bone defect. Therefore, the GTGG composite might be a potential bone substitute.

Purpose: Synthetic bio-degradable materials have been used as an artificial barrier in prophylaxis of adhesions. We report on the use of lactid caprolacton film (Mesofol^®) in recurrent carpal tunnel syndrome. We hypothesise that its use will give favourable results regarding the functional outcome and the recurrence rate.

Patients and methods: Fourteen patients were prospectively reviewed following neurolysis and application of Mesofol^® film. Average age was 48 years. Outcome assessment measures included; two-point discrimination, verbal rating scale, and Boston Questionnaire.

Results: Follow-up period averaged 25.5 months. Post-operative two-point discrimination improved to an average of 4.57 mm. The post-operative average verbal rating scale was 1.5. The mean symptom severity score improved to 1.88 and the mean functional score improved to 1.69 post-operatively.

Conclusion: In cases of recurrent carpal tunnel syndrome, the use of mesofol barrier yields good functional results at the short term follow-up. The technique is simple. No patients needed further surgeries.

Doctors Grow In Vitro Embryonic Human Heart.

Biodegradable Food Box and Plastic Sheet.

Taiwanese Researchers Develop Low Cholesterol Eggs.

Silkworms Potentially Valuable in Vaccine Development.

Permanent metallic stents are frequently used in cardiovascular interventions, due to the many advantages metals possess in bulk and surface properties, design and chemistry, as well as their high modulus and ease of producing thin sections. However, the presence of foreign bodies in humans is associated with many long-term safety concerns; removal of the stent is therefore preferred through a second intervention after recovery. Based primarily on this consideration, biodegradable stents have been of significant interest in the past few years. This paper reports the manufacturing and near-physiological testing of a novel Biodegradable Metallic Coronary Stent (BMCS). To date, very limited literature is available on this aspect of research. Generally, magnesium is reactive and generally difficult to process. However, preliminary results demonstrate strong feasibility of fabricating low-profiled magnesium-based biodegradable coronary stents. Near-physiological tests based on a specially designed accelerated radial stent fatigue system were carried out. Results show that the biodegradable stents retained their arterial scaffolding functions for up to one year (simulated) before totally being resorbed into the biological fluid past its point of functionality. The results obtained so far show great promise for application.

Man has been using plastics for thousands of years, and some of the earlier uses of plastics include spoons, buttons and combs. Today, plastics are used for a myriad of applications, such as for aerospace, microelectronics and water purification. With polymer chemistry, man has been able to alter the properties of plastics or polymers to suit almost any application. Their properties can also be tailored for use as advanced biomedical implants in the human body. An example of such a polymer is the biocompatible lactide/glycolide polyesters. These biodegradable polymers are currently used as sutures, drug delivery systems, temporary implants and even as scaffolds for tissue engineering.

In order to create a functionalized biodegradable polymer for vascular tissue engineering application, poly(DL-lactide-co-RS-β-malic acid) (PDLLMAc) was synthesized. PDLLMAc was obtained after hydrogenolysis of poly(DL-lactide-co-RS-β-benzyl malolactonate) (PDLLMA), which was from the ring-opening polymerization of DL-lactide (DLLA) and RS-β-benzyl malolactonate (MA) using stannous octoate as catalyst. The copolymers were characterized by ¹H-NMR, FTIR, GPC and DSC. The tensile strength and water uptake of the copolymers were measured. In copolymerization, the proportion of MA in the derived copolymers was lower than that in the feeding dose, a consequence of its lower reactivity. The molecular weight of the copolymers decreased with increasing MA content. The protective benzyl groups were completely removed in hydrogenolysis. The glass transition temperature (T_g) of the protected copolymers decreased with increasing MA content. The mechanical strength test showed that the tensile strength of PDLLMA decreased while elongation increased with MA content increasing, and the tensile strength increased and elongation decreased with increasing malic acid content in PDLLMAc for the formation of hydrogen bonding. The water uptake showed that more hydrophilic malic acid adsorbed more water in PDLLMAc. In order to test the reactivity of functional pendant groups, bioactive RGD peptide was immobilized on the functionalized polymer film surface and smooth muscle cells (SMCs) were cultured on it. The results showed that the functionalized copolymer was biocompatible and could be potentially applied in vascular tissue engineering.

The bionanocomposites of soy protein isolate (SPI)/montmorillonite (MMT) have been prepared successfully via simple melt mixing, in which MMT was used as nanofiller and glycerol was used as plasticizer. Their structures and properties were characterized with X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), thermogravimetric analysis and tensile testing. XRD, TEM and SEM results indicated that the MMT layers could be easily intercalated by the SPI matrix even by simple melt processing. The exfoliated MMT layers were randomly dispersed in the protein matrix as MMT content was low (less than 5 wt%), an incomplete exfoliation was evident from SEM results, and some primary particles were observed as the MMT content was high (from 5 wt% to 9 wt%). A significant improvement of the mechanical strength and thermal stability of SPI/MMT nanocomposites has been achieved. Our work suggests that simple melt processing is an efficient way to prepare SPI/MMT nanocomposites with exfoliated structure.

Poly(hydroxyl butyrate-co-valerate) (PHBV) is a biopolymer synthesized by microorganisms that is fully biodegradable with improved thermal and tensile properties with respect to some commodity plastics. However, it presents an intrinsic brittleness that limits its potential application in replacing plastics in packaging applications. Films made of blends of PHBV with different contents of thermoplastic polyurethane (TPU) were prepared by single screw extruder and their fracture toughness behavior was assessed by means of the essential work of fracture (EWF) Method. As the crack propagation was not always stable, a partition method has been used to compare all formulations and to relate results with the morphology of the blends. Indeed, fully characterization of the different PHBV/TPU blends showed that PHBV was incompatible with TPU. The blends showed an improvement of the toughness fracture, finding a maximum with intermediate TPU contents.

Flexible dielectric materials with environmental-friendly, low-cost and high-energy density characteristics are in increasing demand as the world steps into the new Industrial 4.0 era. In this work, an elastomeric nanocomposite was developed by incorporating two components: cellulose nanofibrils (CNFs) and recycled alum sludge, as the reinforcement phase and to improve the dielectric properties, in a bio-elastomer matrix. CNF and alum sludge were produced by processing waste materials that would otherwise be disposed to landfills. A biodegradable elastomer polydimethylsiloxane was used as the matrix and the nanocomposites were processed by casting the materials in Petri dishes. Nanocellulose extraction and heat treatment of alum sludge were conducted and characterized using various techniques including scanning electron microscopy (SEM), thermogravimetric analysis/derivative thermogravimetric (TGA/DTG) and X-ray diffraction (XRD) analysis. When preparing the nanocomposite samples, various amount of alum sludge was added to examine their impact on the mechanical, thermal and electrical properties. Results have shown that it could be a sustainable practice of reusing such wastes in preparing flexible, lightweight and miniature dielectric materials that can be used for energy storage applications.

The application of biodegradable and biocompatible polymer composite is continuously increasing in various fields such as electrical, electronics, construction, automobiles, and aerospace. The synthetic petroleum-based polymers and composite materials are the cause of the accumulation of huge quantities of waste and subsequently affect our natural ecosystem seriously. Hence, to solve this global issue, researchers are focusing on the development of new sustainable, biodegradable polymeric materials, which are cost-effective and easily industrialized to substitute the conventionally used nonbiodegradable polymeric materials. For proper development and design of biodegradable and biocompatible polymer nanocomposite, different behaviors of the prepared materials must be studied. The viscosity and shear modulus of polymer nanocomposites (PNCs) is the product of viscosity or the dynamic shear modulus of the matrix phase of the nanocomposite and volume fraction of the particle. The viscoelastic behavior of the PNCs is strongly influenced by the properties of the polymer matrix and nanoparticle interactions. The different thermomechanical behaviors of polymer and biopolymers include abrasion, thermal shock, mechanical stresses, coefficient of thermal expansion, thermomechanical analysis, thermal stability, $T_g$, thermal expansion, thermal analysis, etc. The biodegradable and biocompatible polymeric materials do not possess adequate thermomechanical properties, therefore, to improve the thermomechanical properties, the material should be blended with other suitable materials. Some of the biocomposite materials such as PLA/PBAT, PLA/PBSA, PLA/PBSA, PLA nanocomposites reinforced with clay materials and some fiber-reinforced polymer composites exhibits good thermomechanical properties.

Branching morphogenesis is a fundamental morphogenetic process in generating glandular tissues. Although the mechanism of branching morphogenesis has been well-explored in the salivary gland development, its interaction with different biodegradable materials has never been investigated. For the purpose of salivary gland regeneration, recapitulation of morphogenetic processes on biodegradable materials might be requisite. Toward this aim, biodegradable biomaterials including poly-lactic-co-glycolic acid (PLGA), poly-epsilon-caprolactone (PCL), and chitosan were examined in the submandibular gland (SMG) culture systems to elucidate their possible impact on salivary morphogenesis. It was found that when SMG explants were cultured on PLGA and PCL, the explants failed to form well-developed branching phenotypes with limited cell migration (5.6 ± 8.8 μm; 10.0 ± 14.1 μm) and decreasing cell viability (56.9% ± 12.5%; 50.3% ± 8.1%). On the contrary, explants cultured on chitosan showed well-developed branches, which were superior in number to those on the control substrata, without any alteration of the morphogenetic phenotypes. Furthermore, the increased cell migration (267.8 ± 45.2 μm) and explants viability (146.8% ± 18.4%) along with the greater deposition of type III collagen, altogether account for better SMG morphogenesis on chitosan. According to the results, it was found that branching morphogenesis of SMG was affected by different biodegradable materials. Chitosan might be an appropriate biodegradable material for salivary morphogenesis, and has applicable potential in the regeneration of salivary tissue.

Bone formation was investigated by ectopic implantation of bioresorbable macroporous calcium phosphate (CMP) matrices combined with rat marrow cells of the athymic mouse. CMP matrices used were macroporous with about 200 μm pore size. CMP matrices were soaked in the subcultured rat marrow cell suspension adjusted to 5 × 10⁷ cells/ml for 30 minutes and then implanted into subcutaneous sites of an athymic mouse. The matrices recovered after 4 and 6 weeks and then uncalcified ground sections were prepared for histological examination. Osteogenesis could be observed in the pore regions at 4 weeks after implantation without fibrous encapsulation. This study thus suggested that the composite grafting of macroporous calcium metaphosphate matrices with marrow derived mesenchymal cells may be useful for repair massive bone defects.

Biodegradable calcium metaphosphate (CMP) sol was prepared and then coated on Ti6A14V substrates by spin-coating technique. In order to investigate the effect of hydrolysis time of (OC₂H₅)₃P on the reaction with Ca(NO₃)₂4H₂O, the P-precursor was pre-hydrolyzed for 1, 5, and 10 hours before the reaction with the Ca-precursor. At least above 5 hours of pre-hydrolysis of P-precursor were required to obtain β -CMP. The CMP coated specimens were dried at 70, 100, and 130°C, respectively and then heat-treated at 630°C for 3 hours with and without holding at 476°C for 2 hours. It has been found that the drying temperature of the CMP coated specimens was one of the most important factors affecting the homogeneity of the coating layer. The optimum drying temperature was 70°C, and the CMP coated layer with holding at 476°C during firing was homogeneous and had fewer cracks, compared with that of sample without holding.