The eminent aim for advance wound management is to provide a great impact on the quality of life. Therefore, an excellent strategy for an ideal wound dressing is being developed that eliminates certain drawbacks while promoting tissue regeneration for the prevention of bacterial invasion. The aim of this study is to develop a bilayer hybrid biomatrix of natural origin for wound dressing. The bilayer hybrid bioscaffold was fabricated by the combination of ovine tendon collagen type I and palm tree-based nanocellulose. The fabricated biomatrix was then post-cross-linked with 0.1% (w/v) genipin (GNP). The physical characteristics were evaluated based on the microstructure, pore size, porosity, and water uptake capacity followed by degradation behaviour and mechanical strength. Chemical analysis was performed using energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectrophotometry (FTIR), and X-ray diffraction (XRD). The results demonstrated a uniform interconnected porous structure with optimal pore size ranging between 90 and 140 μm, acceptable porosity (>70%), and highwater uptake capacity (>1500%). The biodegradation rate of the fabricated biomatrix was extended to 22 days. Further analysis with EDX identified the main elements of the bioscaffold, which contains carbon (C) 50.28%, nitrogen (N) 18.78%, and oxygen (O) 30.94% based on the atomic percentage. FTIR reported the functional groups of collagen type I (amide A: 3302 cm-1, amide B: 2926 cm-1, amide I: 1631 cm-1, amide II: 1547 cm-1, and amide III: 1237 cm-1) and nanocellulose (pyranose ring), thus confirming the presence of collagen and nanocellulose in the bilayer hybrid scaffold. The XRD demonstrated a smooth wavy wavelength that is consistent with the amorphous material and less crystallinity. The combination of nanocellulose with collagen demonstrated a positive effect with an increase of Young's modulus. In conclusion, the fabricated bilayer hybrid bioscaffold demonstrated optimum physicochemical and mechanical properties that are suitable for skin wound dressing.
Observations and modeling studies have shown that during CO2 injection into underground carbonate reservoirs, the dissolution of CO2 into formation water forms acidic brine, leading to fluid-rock interactions that can significantly impact the hydraulic properties of the host formation. However, the impacts of these interactions on the pore structure and macroscopic flow properties of host rock are poorly characterized both for the near-wellbore region and deeper into the reservoir. Little attention has been given to the influence of pressure drop from the near-wellbore region to reservoir body on disturbing the ionic equilibrium in the CO2-saturated brine and consequent mineral precipitation. In this paper, we present the results of a novel experimental procedure designed to address these issues in carbonate reservoirs. We injected CO2-saturated brine into a composite core made of two matching grainstone carbonate core plugs with a tight disk placed between them to create a pressure profile of around 250 psi resembling that prevailing in reservoirs during CO2 injection. We investigated the impacts of fluid-rock interactions at pore and continuum scale using medical X-ray CT, nuclear magnetic resonance, and scanning electron microscopy. We found that strong calcite dissolution occurs near to the injection point, which leads to an increase in primary intergranular porosity and permeability of the near injection region, and ultimately to wormhole formation. The strong heterogeneous dissolution of calcite grains leads to the formation of intra-granular micro-pores. At later stages of the dissolution, the internal regions of ooids become accessible to the carbonated brine, leading to the formation of moldic porosity. At distances far from the injection point, we observed minimal or no change in pore structure, pore roughness, pore populations, and rock hydraulic properties. The pressure drop of 250 psi slightly disturbed the chemical equilibrium of the system, which led to minor precipitation of sub-micron sized calcite crystals but due to the large pore throats of the rock, these deposits had no measurable impact on rock permeability. The trial illustrates that the new procedure is valuable for investigating fluid-rock interactions by reproducing the geochemical consequences of relatively steep pore pressure gradients during CO2 injection.
This paper presents the efficient synthesis of 2-amino-4H-benzo[b]pyrans using mesoporous poly-melamine-formaldehyde as a polymeric heterogeneous catalyst. According to the principals of green chemistry, the reaction was performed by the planetary ball milling process at ambient and neat conditions. The heterogeneous catalyst could be reused up to five runs with no reducing of catalytic efficiency. A variety of substituted 2-amino-4H-benzo[b]pyrans were obtained in good to excellent yields under eco-friendly conditions. Other advantages of the current methodology include short reaction time, wide substrate-scope, and use of a metal-free polymeric catalyst. Also, the current method avoids the use of hazardous reagents and solvents, tedious workup and multi-step purification. This work revealed that porous organic polymers containing Lewis base sites having acceptor-donner hydrogen bonding functional groups, and high porosity could play a vital role in the promotion of the one-pot multicomponent reactions in the solid-phase synthesis.
Activated carbons have been reported to be useful for adsorptive removal of the volatile anaesthetic sevoflurane from a vapour stream. The surface functionalities on activated carbons could be modified through aqueous oxidation using oxidising solutions to enhance the sevoflurane adsorption. In this study, an attempt to oxidise the surface of a commercial activated carbon to improve its adsorption capacity for sevoflurane was conducted using 6 mol/L nitric acid, 2 mol/L ammonium persulfate, and 30 wt per cent (wt%) of hydrogen peroxide (H2O2). The adsorption tests at fixed conditions (bed depth: 10 cm, inlet concentration: 528 mg/L, and flow rate: 3 L/min) revealed that H2O2 oxidation gave desirable sevoflurane adsorption (0.510 ± 0.005 mg/m2). A parametric study was conducted with H2O2 to investigate the effect of oxidation conditions to the changes in surface oxygen functionalities by varying the concentration, oxidation duration, and temperature, and the Conductor-like Screening Model for Real Solvents (COSMO-RS) was applied to predict the interactions between oxygen functionalities and sevoflurane. The H2O2 oxidation incorporated varying degrees of both surface oxygen functionalities with hydrogen bond (HB) acceptor and HB donor characters under the studied conditions. Oxidised samples with enriched oxygen functionalities with HB acceptor character and fewer HB donor character exhibited better adsorption capacity for sevoflurane. The presence of a high amount of oxygen functional groups with HB donor character adversely affected the sevoflurane adsorption despite the enrichment of oxygen functional groups with HB acceptor character that have a higher tendency to adsorb sevoflurane.
Introduction: Diabetic foot ulcer (DFU) is the most distressing complication of diabetes mellitus and often associated with risk of non-traumatic lower extremity amputations. Available formulations and wound dressings for DFU treatment are unfortunately less effective both on controlling and healing DFU. Issues commonly found are associated with providing an optimum environment which facilitates healing process; moist environment, effective oxygen exchange, preventing infection, controlling exudate and also patients compliance. The challenge is therefore to develop a novel drug delivery which address this unmet medical need for better wound treatment of chronic and slow healing DFU. This study aimed to develop a biomaterial based nanofibrous wound dressing formulation containing deferoxamine (DFO), which reported as a potential therapeutic approach to improve wound healing. Deferoxamine regulates the expression and increase stability of hypoxia-inducible factor-1α (HIF-1 α), growthfactor that crucial in wound repair, and thus increase neovascularization. Preparation and characterization of chosen polymers; chitosan/ alginate/polyvinyl alcohol (PVA) for nanofiber formulation will be carried out. Such biodegradable polymer nanofiber is a great benefit for drug delivery owing to its high surface area to volume ratio and high porosity which creates ideal environment to aid in wound healing. Methods: Nanofibers loaded DFO will be fabricated by electrospinning
method that utilizes electrostatic force to produce fine fibers from the polymeric solution. Results: Various polymers concentrations and ratios are investigated to obtain the desired fibers characteristics. The selected optimized DFO nanofibers will be studied for its efficacy in wound healing through in-vivo animal studies. Conclusion: The proposed formulation would be an ideal low cost novel wound dressing with improved healing potential for efficient treatment
of diabetic foot ulcer.
Ginger essential oils (GEO) are natural products with antibacteria properties consisting of many different volatile
compounds have high potential to be used in many applications. In this study, the ginger GEO was successfully
encapsulated in chitosan as a carrier agent using a spray drying technique. The extraction of Zingiber officinale
(ginger) essential oil is performed by steam distillation method. The GEO was encapsulated in chitosan as a carrier
agents at 1:3, GEO:chitosan ratio by using spray drying technique. GEO together with encapsulated GEO were
further assayed for antimicrobial activity by disc-diffusion method. For characterization of encapsulated GEO,
Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FESEM) were
used. FTIR analysis revealed that there was no existence of a new functional group in the encapsulated GEO
showing that there is only physical interaction between GEO and chitosan. Besides, FESEM analysis showed the
encapsulated GEO were in micro in sizes and possessed spherical shape with smooth and porous surface.
Furthermore, Both GEO and encapsulated GEO showed in vitro antimicrobial activity against Escheriachia coli,
Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi with encapsulated GEO possessed higher in
the activities for all studied bacteria compared to GEO. The encapsulated GEO demonstrated a superior performance
against Salmonella typhi with the inhibition zone of 22.5 mm compared to GEO only 13.5 mm. The results obtained
indicated that due to the volatility and instability of the GEO when exposed to environmental factors, its encapsulation considerably improve and enhanced its performance.
This paper describes an investigation on the effect of microbial removal using IMF for high quality drinking water production. The comparison of IMF and IMF-PAC configuration was carried out in the study to highlight the importance of PAC in the system. The specific objective of this study was to study the effect of PAC adsorption in the IMF-PAC system particularly in removing microbial substances from contaminated raw water. A bench scale IMF-PAC configuration using a flat sheet microfiltration membrane was set up for experimental purposes. Experimentally, the result has shown high removal of microbial substances with the IMF-PAC system compared to IMF. The result of E. coli removal achieved was below the detectable level due to the microbial size, which is bigger than membrane pore size. The addition of PAC has shown a direct effect on total microbial removal. The adsorption of microbial onto PAC surfaces reduced the amount of smaller microbial present in permeate samples. As a conclusion, the configuration of IMF is a promising separation process in removing microbial substances, especially when the system is combined with PAC.
In this research, novel ultrafiltration nanocomposite membranes were prepared by incorporating self-synthesized nanoporous titanium dioxide (NTiO2) nanoparticles into polysulfone. The surface of the nanoparticle was treated with a silane-based modifier to improve its distribution in the host polymer. Atomic-force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, transmission electron microscopy, energy-dispersive x-ray spectroscopy, porosity and contact angle tests were conducted to characterize the properties of the particles as well as the fabricated nanocomposite membranes. The effects of the nanoparticle incorporation were evaluated by conducting ultrafiltration experiments. It was reported that the membrane pure water flux was increased with increasing NTiO2 loading owing to the high porosity of the nanoparticles embedded and/or formation of enlarged pores upon addition of them. The antifouling capacity of the membranes was also tested by ultrafiltration of bovine serum albumin fouling solution. It was found that both water flux and antifouling capacity tended to reach desired level if the NTiO2 added was at optimized loading.
Nanostructured photoanodes were prepared via a novel combination of titanium dioxide (TiO2) nanoparticles and mesoporous carbon (C). Four different photoanodes were synthesized by sol-gel spin coating onto a glassy substrate of fluorine-doped tin oxide. The photocatalytic activities of TiO2, TiO2/C/TiO2, TiO2/C/C/TiO2, and TiO2/C/TiO2/C/TiO2 photoanodes were evaluated by exposing the synthesized photoanodes to UV-visible light. The photocurrent density observed in these photoanodes confirmed that an additional layer of mesoporous carbon could successfully increase the photocurrent density. The highest photocurrent density of ~1.022 mA cm(-2) at 1 V/saturated calomel electrode was achieved with TiO2/C/C/TiO2 under an illumination intensity of 100 mW cm(-2) from a solar simulator. The highest value of surface roughness was measured for a TiO2/C/C/TiO2 combination owing to the presence of two continuous layers of mesoporous carbon. The resulting films had a thickness ranging from 1.605 µm to 5.165 µm after the calcination process. The presence of double-layer mesoporous carbon resulted in a 20% increase in the photocurrent density compared with the TiO2/C/TiO2 combination when only a single mesoporous carbon layer was employed. The improved performance of these photoanodes can be attributed to the enhanced porosity and increased void space due to the presence of mesoporous carbon. For the first time, it has been demonstrated here that the photoelectrochemical performance of TiO2 can be improved by integrating several layers of mesoporous carbon. Comparison of the rate of removal of humic acid by the prepared photoanodes showed that the highest performance from TiO2/C/C/TiO2 was due to the highest photocurrent density generated. Therefore, this study showed that optimizing the sequence of mesoporous carbon layers can be a viable and inexpensive method for enhanced humic acid removal.
Dentistry has searched for an ideal material to place in osseous defects for many years. Endogenous bone replacement has been the golden standard but involves additional surgery and may be available in limited quantities. Also, the exogenous bone replacement poses a risk of viral or bacterial transmission and the human body may even reject them. Therefore, before new biomaterials are approved for medical use, mutagenesis systems to exclude cytotoxic, mutagenic or carcinogenic properties are applied worldwide. The present preliminary study was carried out in five male New Zealand white rabbits (Oryctolagus cuniculus). Porous form of synthetic hydroxyapatite granules (500 mg), manufactured by School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Penang, was implanted in the femur of the rabbits. Blood samples were collected prior to implantation and one week after implantation. The blood was cultured in vitro and the cell division was arrested at metaphase using colcemid. This was followed by the hypotonic treatment and fixation. Then, the chromosomes were prepared and stained for analysis. The modal chromosome number of rabbit (Oryctolagus cuniculus) was found to be 2n=44. The mean mitotic index values prior to and after implantation were 3.30 ± 0.66 and 3.24 ± 0.27 per cent respectively. No gross chromosome aberrations, both numerical and structural were noticed either prior to or after implantation of the biomaterial. These findings indicate that the test substance, synthetic hydroxyapatite granules does not produce gross chromosome aberrations under the present test conditions in rabbits.
In this work, mesoporous-activated carbon (CSAC) was prepared from chitosan flakes (CS) via single-step sodium hydroxide activation for the adsorption of methylene blue (MB). CSAC was prepared using different impregnation ratios of NaOH:CS (1:1, 2:1, 3:1, and 4:1) at 800°C for 90min. The adsorption performance of CSAC was evaluated for MB at different adsorption variables, such MB initial concentrations (25-400mg/L), solution pH (3-11), and temperature (30-50°C). The adsorption isotherm data of CSAC-MB were well fitted to Langmuir model with a maximum adsorption capacity 143.53mg/g at 50°C. Best representation of kinetic data was obtained by the pseudo-second order model. CSAC exhibited excellent adsorption uptake for MB and can potentially be used for other cationic dyes.
A new technique was accepted to fill the porosity of Al coating applied by arc thermal spray process to enhance corrosion resistance performance in artificial ocean water. The porosity is the inherent property of arc thermal spray coating process. In this study, applied coating was treated with different concentrations of ammonium phosphate mono basic (NH4H2PO4: AP) solution thereafter dried at room temperature and kept in humidity chamber for 7d to deposit uniform film. The corrosion resistance of Al coating and treated samples have been evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic techniques with exposure periods in artificial ocean water. Electrochemical techniques, X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM) and field emission-scanning electron microscopy (FE-SEM) indicated that phosphate ion would have been retarding corrosion of Al coating effectively. The formation of AHP (Ammonium Aluminum Hydrogen Phosphate Hydrate: NH4)3Al5H6(PO4)8.18H2O) on Al coating surface after treatment with AP is nano sized, crystalline and uniformly deposited but after exposure them in artificial ocean water, they form AHPH (Aluminum hydroxide phosphate hydrate Al3(PO4)2(OH)3(H2O)5) that is very protective, adherent, uniform and plate like morphology of corrosion products. The AHPH is sparingly soluble and adherent to surface and imparted improved corrosion resistance.
The mechanical, thermal, and morphological properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA) based scaffold were investigated. In this study, a scaffold containing P. purpureum and PLA was produced using the solvent casting and particulate leaching method. P. purpureum fibre, also locally known as Napier grass, is composed of 46% cellulose, 34% hemicellulose, and 20% lignin. PLA composites with various P. purpureum contents (10%, 20%, and 30%) were prepared and subsequently characterised. The morphologies, structures and thermal behaviours of the prepared composite scaffolds were characterised using field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The morphology was studied using FESEM; the scaffold possessed 70-200μm-sized pores with a high level of interconnectivity. The moisture content and mechanical properties of the developed porous scaffolds were further characterised. The P. purpureum/PLA scaffold had a greater porosity factor (99%) and compression modulus (5.25MPa) than those of the pure PLA scaffold (1.73MPa). From the results, it can be concluded that the properties of the highly porous P. purpureum/PLA scaffold developed in this study can be controlled and optimised. This can be used to facilitate the construction of implantable tissue-engineered cartilage.
High proportion of copper has become a global challenge owing to its negative impact on the environment and public health complications. The present study focuses on the fabrication of a polyvinylidene fluoride (PVDF)-polyvinyl pyrrolidone (PVP) fiber membrane incorporated with varying loading (0, 0.5, 1.0, 1.5, and 2.0 wt%) of titanium dioxide (TiO2) nanoparticles via phase inversion technique to achieve hydrophilicity along with high selectivity for copper removal. The developed fibers were characterized based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), permeability, porosity, zeta potential, and contact angle. The improved membrane (with 1.0 wt% TiO2) concentration recorded the maximum flux (223 L/m2·h) and copper rejection (98.18%). Similarly, 1.0 wt% concentration of TiO2 nanoparticles made the membrane matrix more hydrophilic with the least contact angle of 50.01°. The maximum copper adsorption capacity of 69.68 mg/g was attained at 1.0 wt% TiO2 concentration. The experimental data of adsorption capacity were best fitted to the Freundlich isotherm model with R2 value of 0.99573. The hybrid membrane developed in this study has considerably eliminated copper from leachate and the concentration of copper in the permeate was substantially reduced to 0.044 mg/L, which is below standard discharge threshold.
The current research aimed at designing mesoporous silica nanoparticles (MSNs) for a controlled coadministration of salicylic acid (SA) and ketoconazole (KCZ) to effectively treat highly resistant fungal infections. The sol-gel method was used to formulate MSNs, which were further optimized using central composite rotatable design (CCRD) by investigating mathematical impact of independent formulation variables such as pH, stirring time, and stirring speed on dependent variables entrapment efficiency (EE) and drug release. The selected optimized MSNs and pure drugs were subjected to comparative in vitro/in vivo antifungal studies, skin irritation, cytotoxicity, and histopathological evaluations. The obtained negatively charged (-23.1), free flowing spherical, highly porous structured MSNs having a size distribution of 300-500 nm were suggestive of high storage stability and improved cell proliferation due to enhanced oxygen supply to cells. The physico-chemical evaluation of SA/KCZ-loaded MSNs performed through powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) indicates absolute lack of any interaction between formulation components and successful encapsulation of both drugs in MSNs. The EESA, EEKCZ, SA release, and KCZ release varied significantly from 34 to 89%, 36 to 85%, 39 to 88%, and 43 to 90%, respectively, indicating the quadratic impact of formulation variables on obtained MSNs. For MSNs, the skin tolerability and cell viability percentage rate were also having an extraordinary advantage over suspension of pure drugs. The optimized SA/KCZ-loaded MSNs demonstrated comparatively enhanced in vitro/in vivo antifungal activities and rapid wound healing efficacy in histopathological evaluation without any skin irritation impact, suggesting the MSNs potential for the simultaneous codelivery of antifungal and keratolyic agents in sustained release fashion.
The current strategy for rapid wound healing treatment involves combining a biomaterial and cell-secreted proteins or biomolecules. This study was aimed at characterizing 3-dimensional (3D) collagen hydrogels fortified with dermal fibroblast-conditioned medium (DFCM) as a readily available acellular skin substitute. Confluent fibroblasts were cultured with serum-free keratinocyte-specific medium (KM1 and KM2) and fibroblast-specific medium (FM) to obtain DFCM. Subsequently, the DFCM was mixed with collagen (Col) hydrogel and chondroitin-4-sulphate (C4S) to fabricate 3D constructs termed Col/C4S/DFCM-KM1, Col/C4S/DFCM-KM2, and Col/C4S/DFCM-FM. The constructs successfully formed soft, semi-solid and translucent hydrogels within 1 h of incubation at 37 °C with strength of <2.5 Newton (N). The Col/C4S/DFCM demonstrated significantly lower turbidity compared to the control groups. The Col/C4S/DFCM also showed a lower percentage of porosity (KM1: 35.15 ± 9.76%; KM2: 6.85 ± 1.60%; FM: 14.14 ± 7.65%) compared to the Col (105.14 ± 11.87%) and Col/C4S (143.44 ± 27.72%) constructs. There were no changes in both swelling and degradation among all constructs. Fourier transform infrared spectrometry showed that all groups consisted of oxygen-hydrogen bonds (O-H) and amide I, II, and III. In conclusion, the Col/C4S/DFCM constructs maintain the characteristics of native collagen and can synergistically deliver essential biomolecules for future use in skin therapeutic applications.
In this study, poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) dual-layer membranes filled with 0-3 wt% cellulose nanowhisker (CNWs) were fabricated with aim to remove metal ions from wastewater. An integrated method was employed in the membrane fabrication process by combining water vapor-induced and crystallization-induced phase inversions. The membrane thickness was measured in between 11 and 13 μm, which did not pose significant flux deviation during filtration process. The 3% CNW filled membrane showed prominent and well-laminated two layers structure. Meanwhile, the increase in CNWs from 0 to 3% loadings could improve the membrane porosity (43-74%) but reducing pore size (2.45-0.54 μm). The heat resistance of neat membrane enhanced by 1% CNW but decreased with loadings of 2-3% CNWs due to flaming behavior of sulphated nanocellulose. Membrane with 3% CNW displayed the tensile strength (23.5 MPa), elongation at break (7.1%), and Young's modulus (0.75 GPa) as compared to other samples. For wastewater filtration performance, the continuous operation test showed that 3% CNW filled membrane exhibited the highest removal efficiency for both cobalt and nickel metal ions reaching to 83% and 84%, respectively. We concluded that CNWs filled dual-layer membranes have potential for future development in the removal of heavy metal ions from wastewater streams.
Hydrogels are an attractive system for a myriad of applications. While most hydrogels are usually formed from synthetic materials, lignocellulosic biomass appears as a sustainable alternative for hydrogel development. The valorization of biomass, especially the non-woody biomass to meet the growing demand of the substitution of synthetics and to leverage its benefits for cellulose hydrogel fabrication is attractive. This review aims to present an overview of advances in hydrogel development from non-woody biomass, especially using native cellulose. The review will cover the overall process from cellulose depolymerization, dissolution to crosslinking reaction and the related mechanisms where known. Hydrogel design is heavily affected by the cellulose solubility, crosslinking method and the related processing conditions apart from biomass type and cellulose purity. Hence, the important parameters for rational designs of hydrogels with desired properties, particularly porosity, transparency and swelling characteristics will be discussed. Current challenges and future perspectives will also be highlighted.