Papers by Keyword: Alginate

Abstract: Studies on hydroxyapatite are plentiful since the compounds are alike to the bone and sometimes combined with Zn to fabricate a longstanding structure and improve cell regeneration. However, construct a 3D model of HAp-Zn through sintering required high energy. Therefore, this study performed a low-temperature process using alginate, taking a role as a matrix, to achieve an interconnected porous structure while maintaining mechanical properties. The variations of alginate concentrations (0%, 2%, 4%, and 6%) were mixed with HAp-Zn powder using PBS and CaCl₂. The bone scaffold was then characterized using XRD, FTIR, SEM, and compressive test. The XRD result showed that alginate addition did not change the HAp-Zn structure and phase. The degree of crystallinity and crystallite size was found to decrease with the increasing composition of alginate. The FTIR spectra also displayed an intermolecular interaction between HAp-Zn and SA. On the other hand, the SEM observation contained well interconnectivity with 50-200 μm of pore size. It led to an incline in ultimate compressive strength and modulus of elasticity with the uppermost value was 2.05 ± 0.06 MPa and 0.037 ± 0.001 GPa respectively in 6% of alginate.

Abstract: This research is about the fabrication and properties study of the alginate bio-composites film for potential use in food sensing applications. A response surface methodology (RSM) was employed to optimize the concentration of sodium alginate (1 to 5% w/v), glycerol (0.4 to 0.8% w/v), and maltodextrin (0.4 to 0.8% w/v) as a function of the tensile strength (TS) and elongation at break (EB) and toughness (T) of the biofilms. The coefficient determination (R²) result obtained for TS against alginate, glycerol and maltodextrin is 81.05%, while for EB and T are 32.07% and 64.70% respectively. It showed that the addition of sodium alginate, glycerol and maltodextrin at different concentrations had significantly affected the TS but no effect on EB and T was observed. The optimization study of the film produces two conditions which are conditions 1 and 2. The optimum conditions parameter for condition 1 is a film with 3.0% alginate concentration, 1.0g/g of glycerol content, and 1.50g/g of maltodextrin content while condition 2 was 1.0% of alginate concentration, 1.0g/g of glycerol content and 0.0g/g maltodextrin content. The values of the TS obtained at the optimized condition were 4.75 MPa and 22.99 MPa which is lower than the predicted value of condition 1 (7.0 MPa) or the maximized TS at condition 2 respectively. The thickness value of edible films in this study had an average of 0.54 mm which was higher than the maximum standard thickness of edible films according to the Japanese Industrial Standard (JIS) which is 0.25 mm. Water Vapour Permeability (WVTR) study indicated that all alginate films in this study had a value higher than the JIS 1975 standard of WVTR for edible films which is at a maximum of 10 g/m²/24 hours. The natural colour from Clitoria Ternatea was successfully immobilized into the alginate-based film and the film become dark purple. Based on the result obtained, prediction equations for responses studied are adequate to describe the experimental data on tensile strength, elongation at break, and toughness. However, further modifications are necessary for improvements in mechanical characteristics in the future.

Abstract: The surface has a vital function in the tissue's response to the presence of foreign material in the field of body implants. Surface modification with coatings can be adjusted to provide the highest service performance at the lowest cost. Coatings can increase corrosion resistance by reducing metal ion and corrosion product migration in the body. We fabricated polymer based bio-composite coatings by blending chitosan (Chi), alginate (Alg) and nanoparticles ((TiO₂, Nb₂O₅) by dip coating onto a 316L stainless steel substrate. The coatings’ surface morphology and phases were studied using FESEM and FTIR analysis. The wettability behavior of the coated samples was also studied by investigating their contact wetting attributes. The antibacterial activity of the functionalized coatings was determined too. The FTIR results showed that the blending of Chi-Alg and nanoparticles was excellent, and no obvious differences in the spectra or any changes in the structures of the polymer matrices were observed. The SEM results demonstrated that the coating layers were uniform, homogeneous, and crack-free on the 316L Stianless steel substrate when using TiO₂-Nb₂O₅ nano particles. The contact angle results showed the highly hydrophilic properties of the pure chitosan-alginate blend. As well, coatings containing nano particles showed the same antibacterial effect of chitosan-alginate blend coating.

Abstract: In this research, Fe₃O₄ NPs and g-C₃N₄ nanosheets were synthesized by co-precipitation and the thermal decomposition method, respectively. The ZnO/g-C₃N₄/Fe₃O₄ nanocomposites (ZGF) with the varying weight sight of Fe₃O₄ NPs were 0.5 (0.5ZGF), 1.25 (1.25ZGF), 2.5 (2.5ZGF), and 5.0 (5.0ZGF) wt%, which were synthesized by a facile method. Synthesized Fe₃O₄ NPs, g-C3N4 nanosheets, and ZGF nanocomposite were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM). Then ZGF nanocomposites were contained on sodium alginate-polyvinyl alcohol (SA-PVA) as hydrogel packing material. Kinetics of photocatalytic activity and adsorption were studied by first-order reaction, second-order reaction, the pseudo-first-order, the pseudo-second-order, Elovich, and Avrami models. Especially, the photocatalytic activity and adsorption process of ZGF-SA-PVA composite hydrogel beads have been represented via Methylene Blue removal. The photodegradation efficiency of 2.5ZGF-SA-PVA composite hydrogel beads under visible light irradiation is increased by over 2 times, to be much higher than that of SA-PVA hydrogel beads. The results show that the organic removal efficiency of the SA-PVA hydrogel bead can be effectively improved by the ZGF nanocomposite.

Abstract: Microparticle protein delivery system using alginate and cellulose derivative (HPC, HEC and CMC) composite system was prepared using external gelation with vibration technology. Bovine serum albumin (BSA) as a model protein was encapsulated using these biodegradable materials. This preparation showed an increase in encapsulation efficiency in comparison to the samples where pure alginate was used as the encapsulating material. Compared with the other microparticles, the 50:50 alginate/HEC samples exhibited significant encapsulation efficiency. Consequently, its release rate in the acidic medium was comparatively substantial and higher cumulative release in the simulated intestinal fluid (SIF) medium at the end of the dissolution study was observed to be high at around 86.17%.

Abstract: Zeolite have been widely used as gas separation material with its promising properties. One of gas separation technology available is using membrane composites because of its various benefits. A synthesis of membrane composites consists of zeolite/alginate then caried out to study the effect of the addition of Ethylene Glycol (EG) to the CH₄/CO₂ selectivity performance of the membrane. Membrane synthesis varied by its mass ratio of alginate:EG for 1:0, 1:0.25, 1:0.5, 1:1, and 1:2 and evaporated in the room temperature for 72 h. Characterization of the physico/chemical properties was done with various instruments such as FT-IR (Fourier Transform Infra-Red) Spectroscopy, Texture Analyzer, SEM (Scanning Electron Microscopy), and Permeation Test Cell Unit. Addition of EG into the membrane compositions proven to improve the separation performance showed by permeation rate improvement and selectivity value. Gas selectivity separations of CH₄/CO₂ was also investigated and it can be concluded that the synthesized membranes have several promising properties to be used as CH₄/CO₂ separations membranes.

Abstract: The adsorption studies of coomassie brilliant blue (CBB) on alginate-chitosan nanoparticles (ACNPs) have been carried out by synthesizing alginate-chitosan nanoparticles and dropping with sodium tripolyphosphate and CaCl₂. CBB before and after adsorbed were analyzed using a UV-Vis spectrophotometer. Nanoparticle characterizations were done using infrared spectrophotometer (FT-IR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). Alginate-chitosan nanoparticles obtained were ivory white powder that has a rough surface with an average size of 50.62 nm. Investigation also showed that the ACNPs were able to adsorb CBB with an optimum adsorption capacity 53.25 mg/g at pH 2, the contact time of 90 min, and the initial concentration 100 ppm of adsorbate. The adsorption process of CBB followed pseudo-second order kinetics and the Dubinin-Radushkevich isotherm model.

Abstract: In this study, chitosan (Chi), alginate (Alg), and mesoporous phosphotungstic acid (mPTA) were used as electrolyte membrane materials for DMFC. Chi and Alg will be crosslinked with mPTA filler to improve the performance of the electrolyte membrane. Characterizations carried out include tensile tests, methanol permeability, and proton conductivity. The results of the tensile test showed that the Chi-Alg(3:1) membrane had a higher tensile strength value (26.64 N/mm²) than the pure chitosan membrane (11.97 N/mm²). The results of methanol permeability show that the Chi-Alg(3:1)/mPTA(2.0%) membrane has a lower methanol permeability value (8.17 × 10^-6 cm² s^-1) and a relatively high proton conductivity value, (45.8 × 10^-3 S cm^-1). Chi-Alg/mPTA membrane, simplicity of the used simple preparation method and the cost reduction can be applied as an electrolyte membrane for DMFC.

Abstract: The effect of bentonite (BT) on the structure and performance of sodium alginate (SA) as microsphere carrier of essential oil is studied. The addition of BT can improve the performance of alginate gel microspheres through the study of the properties of single carrier SA and composite carrier SA/BT. The experimental results show that the viscosity of composite carrier SA/BT solution is higher than that of carrier SA solution, and the increasing rate of viscosity of composite solution with temperature is less than that of SA. The addition of BT can effectively inhibit the swelling of SA microspheres. The hydrogen bonding between SA and BT is shown in FTIR, and the interlayer spacing of BT crystal structure is not changed in XRD analysis. The mass loss rate of SA/BT microspheres is lower than that of SA in TGA analysis. The more dense structure of SA/BT microspheres than that of SA microspheres is confirmed by SEM. The release rate of cinnamon oil in SA/BT gel microspheres is significantly lower than that in SA gel microspheres under different temperature conditions. The addition of BT could better control the volatilization of essential oil encapsulated in SA gel microspheres.

Abstract: Spinal cord injury is damage to the spinal cord which causes lesions in the spinal cord and leads to an increase in extracellular Ca²⁺. It results in additional neuronal loss which causes temporary/permanent disability or even death. The aim of this study was to determine characteristics and the best composition of alginate – chitosan hydrogel responsive to Calcium (Ca²⁺) for spinal cord injury. Hydrogel synthesis with its compositions, namely chitosan was dissolved in 0.4% acetic acid, neutralized in pH 7 with 0.5 M NaOH, added some 0.85% NaCl in it, and added 5 alginate variations which were dissolved in 0.85% NaCl, next will centrifugation method. Based on the FTIR test, hydrogel showed stretching vibrations of Chitosan’s O–H bonds appeared in 3415.93cm^-1 wavenumber, while Na groups of alginate isomer appeared in 1413.82 cm^-1 wavenumber. The results of the cytotoxicity test using the MTT Assay method showed live cell percentage from less than 50% to 52.61% in Sample B and 83.83% in Sample C. The results of the injectability test showed that all samples were injectable with the highest percentage of injectability at 98.283%. The results of the UV-Vis spectrophotometric test showed that all hydrogel samples were able to absorb Ca²⁺. Hydrogels can be degraded at more than 90% within 14 days. The results of the morphology test (SEM) obtained 84.7-99.6 μm pore sizes.