Papers by Keyword: Biodegradable

Abstract: Microparticles of sand silica have been mixed with biodegradable waste (polylactic acid) from the fused filament fabrication process to investigate the impact on the mechanical properties. The composite mixtures were prepared using different compositions via a twin extrusion machine. Mechanical characterization using the Tensile Testing Machine was performed. The peak strength values indicated that increasing silica composition increased the tensile strength from 62.8 MPa at 0 wt% to 121.03 MPa at 10 wt%. However, a drop was observed beyond this point. It was concluded that for the yield strength, toughness, and failure strain, a similar trend was observed, and the values of the material increased up to 10 wt%, which corresponds to the increased mechanical property of the mixtures with reinforcement of silica microparticles. It is demonstrated that the mechanical properties have been improved for the processed material attributing to the impact of the recycling process of the polylactic acid from leftover 3D printing waste and promoting its potential reuse in the same application.

Abstract: Serial poly (lactic acid) (PLA) and thermoplastic starch (TPS) blends (with a fixed content of 20 wt.% TPS) were prepared by melt extrusion process. The effect of different molecular weight of PEG on the thermal and rheological properties of PLA/TPS blends was studied by the melt flow rate (MFR) and DSC analysis. The results showed that the molecular weight of PEG influenced the miscibility and crystallization behavior of PLA/TPS blends. Blend added with PEG400 showed a single T_g, and blends with PEG600 provided remarkable improvement of rheological properties with an increase in flow rate to 49.02 g/10 min. 4% content of poly (ethylene glycol) (PEG) can positively contribute to improve crystallization rate of PLA by reducing the melting temperature and cold crystallization temperature.

Abstract: The Zn-Mg alloy is a suitable candidate for the manufacture of biomaterials that can be excessively degraded in the human body without producing a mixture. This study was conducted with the aim to determine variations in the mechanical characteristics of Zn-Mg alloys with Mg ratio of 1%, 3%, 5%, and 7%wt, and to study variations in composition and sintering of the degradation rate of Zn-alloy Mg uses the powder metallurgy method. The synthesis results were characterized by using a defense test and obtained the best value at Zn7% Mg of 117.5 ± 25.37. The presence of MgZn₂ and Mg₂Zn₁₁ phases that were confirmed by XRD characterization could increase the material hardness. Dynamic degradation test was carried out on samples with the best mechanical properties (Zn7% Mg) with variations in compacting pressure and sintering temperature. The increase in compaction pressure and sintering temperature could reduce the degradation rate of Zn-Mg alloys. The best degradation test was obtained at a pressure of 400 MPa with a sintering temperature of 400°C of 0.70mmpy. The degradation test results were as expected because previous studies stated at the degradation rate (0.40mmpy-1.53mmpy) on statistical testing and the degradation rate (4.9-7.0) mmpy on the change policy supported for bone scaffolding applications. Scanning Electron Microscope (SEM) characterization results showed that samples with compacting pressure and low sintering temperature do not have perfect particle bonding. Samples with high compacting pressure and sintering temperature have good bonding between particles so they do not have a pore composition in the alloy.

Abstract: In this research, the nanostructured alginate (AL) membranes were prepared with natural bioactive compound, Cat's claw (Uncaria tomentosa) extract (UT). UT is broadly used as an anti-inflammatory agent and the effect on the treatment of Rheumatism was proved by many scientists. For this reason, we added this bioactive compound in the process of AL membrane formulation to improve the biological activities. 2-dimentional (2-D) and 3-dimentional (3-D) AL membranes were prepared with and without addition of UT extracts. 3-D AL membranes were prepared using ultrasound with high intensity. The wettability of AL membranes depending on the concentration of AL was studied by measuring contact angle and surface energy. Stabilization agent, poloxamer 407, was used to improve the stability of AL nanoemulsion. The effects of UT in 3-D AL membranes were studied by measuring swelling behavior and contact angle. The surface morphology was measured with scanning electron microscopy (SEM). Comparing to 2-D AL membranes, 3-D AL membranes presented rougher surface due to AL nanoparticles presence. When UT was incorporated in AL membranes, strong antioxidant activity and higher contact angle and swelling ratio were observed than non-UT incorporated AL membranes.

Abstract: Wound healing is a natural process of human body. When the wound size exceeds the critical point for naturally body healing, the fibrous tissue will play their parts and created a scar. Therefore, extra treatment has been added to eliminate the body limitations. Currently, there are a lot of commercial bioactive wound healing and dressing due to its physiological and biological abilities. In wound healing process, high moisture condition is also required. In order to accelerate the wound healing process, Tissue engineering (TE) is recommended. The increasing of cell proliferation by TE will be increased the chance for wound healing acceleration. In this study, the combination of Gelatin (Gel), Chitosan (CS) and Silk Fibroin (SF) were varied mixed in 10 ratios and fabricated the structure by lyophilisation technique. The elastic ability, biodegradability, structure and pore morphology, porosity, swelling ability, and biotoxicity were observed in each ratio. Gel provided highest elastic ability and biodegradability. The addition of SF and CS in Gel decreased biodegradation rate and activate fibroblast cell proliferation. Therefore, CS and SF could increase efficiency of gelatin-base wound dressings for a variety of utilization.

Abstract: This work was focused on the effects of filler concentration on the antibacterial activity and biodegradable behavior of poly (butylene succinate) (PBS) composite films containing silver exchanged zeolite ZSM-5 (SZSM-5). The composite films were prepared by chill roll cast film extrusion, by varying the silver zeolite content from 0.5 to 4 %wt. The silver content in zeolite was examined by energy dispersive X-ray spectroscopy (EDX). The morphology and crystal structure of silver zeolite were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique, respectively. The incorporation of silver did not influence the zeolite morphology and its crystal structure. The antibacterial action of composite films was investigated against gram-negative Escherichia coli and gram-positive Staphylococcus aureus. The results revealed that the PBS composite films containing SZSM-5 showed 99.9% of bacterial reduction. The optimal SZSM-5 content in PBS composite films was 0.5%wt because it was the lowest concentration that showed high efficiency of antibacterial behavior. In case of biodegradable ability, PBS composite films incorporated with 0.5%wt of SZSM-5 exhibited the degradation after three-month of soil burial test, although they exhibited slower rate than neat PBS films. The SEM micrographs of the films after soil burial test displayed the cavity on film surface, indicating the biodegradable properties of the films. PBS composite films incorporated with 0.5%wt of SZSM-5 showed the potential to be used as the food packaging.

Abstract: Hyaluronic acid (HA)-based hydrogels are widely used in biomedical applications due to their excellent biocompatibility and enzymatic degradability. In this paper a photo-crosslinking double-network hyaluronic acid-based hydrogel dressing was proposed. Hyaluronic acid can be UV-crosslinked by modification with methacrylic anhydride (HA-MA) and disulfide-crosslinked by modification with 3,3'-dithiobis (propionylhydrazide) (DTP) (HA-SH). The mixings of these two materials at different ratios were produced. All the samples can be quickly gelled at 365 nm for 10 s. The rheological tests show that the storage modulus (G') of the double network (HA-SH/HA-MA) hydrogel is increased with the increase of HA-SH content. The HA-SH/HA-MA hydrogel has porous structure, high swelling ratio and Controlled degradation rate. In vitro degradation tests show that the ratio of HA-SH/HA-MA ratio was 9:1 (S9M1) in 100 U/ml hyaluronidase (Hase) degraded by 89.91±2.26% at 11d. The cytocompatibility of HA-SH/HA-MA hydrogels was proved by Live/Dead stainings and CCK-8 assays in the human dermis fibroblasts (HDF) cells test. All these results highlight the biological potential of the HA-SH/HA-MA hydrogels for DFU intervention.

Abstract: This work aims to review current trends in research within the field of iron-based scaffolds for orthopaedic applications. Current research is trapped in a ‘see-saw’ type problem where an increase in corrosion rate of the base metal is required to accelerate the degradation process making the resorption time compatible with the healing time. This is done via several methods including porosity control, cathodic element addition and/or patterning and alloying. In turn, this increase in corrosion rate causes the local concentration of metallic ions to increase beyond the toxicity limit for osteoblast type cells, thus negatively effecting cytocompatibility. This is most pronounced when considering the orthopaedic environment, in which static conditions provide for increased local ion concentrations, resulting in local toxicity. However, research from the medical field of Thalassemia may help solve this dilemma by providing chelation medicine for patients undergoing implantation of resorbable orthopaedic scaffolds, throughout the resorption period. Excretion of iron would then be provided mainly through bowel movement and urination.

Abstract: This paper shows the results of the mechanical characterisation of a series of new sustainable polymeric formulations filled with almond shell and cellulosic fibres for its use in rotomoulding process. Up to ten formulations of polyethylene and polycaprolactone, were developed with a content from 10 to 40 wt% of natural filler. The addition of these fillers decreased the mechanical properties, mainly when the formulation was carried out by physical mixing. However, good interfacial interaction between the polymer and filler was produced in the compounding process, obtaining final formulations appropriated for rotomoulding.

Abstract: A protein-based electrospun nanofiber from cold water fish gelatin (FG) including bovine lactoferrin (L) as an antimicrobial substance for food packaging applications was developed. Various amounts of L (0, 5, 10, 15, and 20%) were incorporated into FG electrospun nanofibers in order to test antimicrobial activity by disc diffusion method against Pseudomonas fluorescens, Acinetobacter johnsonii, Aeromonas hydrophila, Flavobacterium psychrophilum, Shewanella putrefaciens, and Escherichia coli commonly cause problems in food safety especially in fish products. It was obviously seen that 15% and 20% wt L incorporated FG electrospun nanofibers had significant inhibition zone against all bacterial strains while 5% and 10% L-FG had lower antimicrobial effects. In order to recommend fish gelatin as a food packaging material, mechanical properties should be enhanced to be competitive with synthetic polymers. It was revealed that mechanical strength of gelatin electrospun nanofibers depended on both fiber morphology and bioactive substance content. Neat FG (N-FG ) bead-free electrospun mats had higher fiber diameter (815 ±40 nm) while 15% and 20% L-FG had relatively lower diameter with beaded morphology, i.e., 348 ±32 nm, 229 ± 44 nm respectively. The tensile strength of 20% L-FG mats was significantly lower than the N-FG mats due to beady and thinner morphology. It can be concluded that L-FG electrospun nanofibers with high antimicrobial activity and improvable tensile strength is promising for active packaging applications.Keywords: Electrospinning, Pseudomonas spp., Escherichia coli, Shewanella spp., biodegradable, active packaging