Bacterial cellulose impregnated with andaliman (Zanthoxylum acanthopodium) microencapsulation as diabetic wound dressing.

Diabetic foot ulcer (DFU) is a common complication of diabetes mellitus which can cause infection, amputation and even death. One of many treatments that can be applied to support the DFU healing processes is by using wound dressings. Bacterial cellulose (BC) is a good material to be used as a wound dressing. However, some of the limitations of BC to be applied as wound dressing are does not possess antibacterial properties and support the healing process. Andaliman (Zanthoxylum acanthopodium) is known to have antioxidant, antibacterial and anti-inflammatory abilities that can support BC as a wound dressing. This research focused on the manufacture of BC/Z. acanthopodium microencapsulated wound dressing composites and evaluate their potential as a DFU wound dressing with a variety of gelatin composition in microencapsulation. The results of FTIR and SEM analysis showed that the Z. acanthopodium impregnation process in BC was successful. The variation of gelatine that used in microencapsulation affected the morphological and effectiveness of the wound dressing. However, overall, the wound dressings showed good antibacterial effect on E. coli and S. aureus bacteria and accelerating the wound closure process 8 times faster (BCAMc12) on the 17th day compared to wounds that did not receive any treatment.

Photocatalytic Degradation of Methylene Blue Using N-Doped ZnO/Carbon Dot (N-ZnO/CD) Nanocomposites Derived from Organic Soybean.

This study reports on successful synthesis of carbon dots (CDs), nitrogen-doped zinc oxide (N-ZnO), and N-ZnO/CD nanocomposites as photocatalysts for degradation of methylene blue. The first part was the synthesis of CDs utilizing a precursor from soybean and ethylenediamine as a dopant by a hydrothermal method. The second part was the synthesis of N-ZnO with urea as the nitrogen dopant carried out by a calcination method in a furnace at 500 °C for 2 h in an N2 atmosphere (5 °C min-1). The third part was the synthesis of N-ZnO/CD nanocomposites. The characteristics of CDs, N-ZnO, and N-ZnO/CD nanocomposites were analyzed through Fourier transform infrared (FTIR), UV-vis absorbance, photoluminescence (PL), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), thermal gravimetry analysis (TGA), field-emission scanning electron microscopy energy-dispersive spectroscopy (FESEM EDS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analysis. Based on the HR-TEM analysis, the CDs had a spherical shape with an average particle size of 4.249 nm. Meanwhile, based on the XRD and HR-TEM characterization, the N-ZnO and N-ZnO/CD nanocomposites have wurtzite hexagonal structures. The materials of N-ZnO and N-ZnO/CD show increased adsorption in the visible light region and low energy gap E g. The E g values of N-ZnO and N-ZnO/CDs were found to be 2.95 and 2.81 eV, respectively, whereas the surface area (S BET) values 3.827 m2 g-1 (N-ZnO) and 3.757 m2 g-1(N-ZnO/CDs) belonged to the microporous structure. In the last part, the photocatalysts of CDs, N-ZnO, and N-ZnO/CD nanocomposites were used for degradation of MB (10 ppm) under UV-B light irradiation pH = 7.04 (neutral) for 60 min at room temperature. The N-ZnO/CD nanocomposites showed a photodegradation efficiency of 83.4% with a kinetic rate of 0.0299 min-1 higher than N-ZnO and CDs. The XRD analysis and FESEM EDS of the N-ZnO/CDs before and after three cycles confirm the stability of the photocatalyst with an MB degradation of 58.2%. These results have clearly shown that the N-ZnO/CD nanocomposites could be used as an ideal photocatalytic material for the decolorization of organic compounds in wastewater.

Acetylated lignin from oil palm empty fruit bunches and its electrospun nanofibres with PVA: Potential carbon fibre precursor.

The electrospinning of acetylated lignin/polyvinyl alcohol (PVA) nanofibres was carried out to expand the application of lignin materials obtained from oil palm empty fruit bunches (OPEFB). Lignin was isolated by the steam explosion method and subsequently precipitated using H2SO4. Acetylated lignin was produced by mixing acetic anhydride and pyridine at a 2:1 v/v ratio. Following the acetylation process, FTIR analysis showed the absorption of the C=O carbonyl group at wavenumber 1714.6 cm-1. The chemical structures of isolated and acetylated lignin were established using 1H NMR spectral analysis, and XRD examination demonstrated their amorphous character. The electrospinning process of acetylated lignin and PVA solution was then carried out at 15 kV voltage, 0.8 mL/h flow rate, and 12 cm distance between the needle and collector. The sample exhibited electrical conductivity of 443 µS/cm and viscosity of 2.8 × 10-3 Pa s. The morphology analysis showed that there were more beads on the surface of lignin/PVA nanofibres than acetylated lignin/PVA nanofibres. In addition, acetylated lignin/PVA nanofibre was more stable than lignin/PVA. The G-band of carbonized material increased with the presence of lignin. The works presented suggest the potential of using waste materials such as OPEFB as a suitable precursor for the preparation of carbon fibre.

Bioactive bacterial cellulose wound dressings for burns with collagen in-situ and chitosan ex-situ impregnation.

Bacterial cellulose (BC) is a biopolymer that commonly used for wound dressings regarding to its high in-vitro and in-vivo biocompatibility. Moreover, the three-dimensional fibers in BC become an advantageous for bioactive wound dressing application as they serve as templates for impregnation other supportive materials. Chitosan and collagen are two of the materials that can be impregnated to optimize the BC properties for serve as wound dressing material. Collagen can help skin cells grow on the wound sites, where chitosan has anti-bacterial properties and can bind red blood cells. BC-based wound dressings were made by impregnating collagen via in-situ method followed by immersing chitosan via ex-situ method into BC fibers for 24 h. The intermolecular interactions of amine groups in the wound dressing were confirmed by FTIR. The XRD diffractogram showed wider peaks at 14.2°, 16.6°, and 22.4° due to the presence of collagen and chitosan molecules in the BC fibers. SEM images confirmed that chitosan and collagen could penetrate BC fibers well. Other tests, such as water content, porosity, antibacterial properties, and haemocompatibility, indicated that the wound dressing was non-hemolytic. In-vivo test indicated that BC/collagen/chitosan wound dressing supported the wound healing process on second degree burn.

Carbon-Nano Fibers Yield Improvement with Iodinated Electrospun PVA/Silver Nanoparticle as Precursor via One-Step Synthesis at Low Temperature.

High temperature is required in carbon fiber synthesis in the carbonization step. However, direct high-temperature heating without the presence of additive materials would affect the yield and structure of carbon fibers produced. Thus, this study aims to synthesize carbon fibers from poly-vinyl alcohol (PVA), as the precursor and reducing agent, using silver nanoparticles (SNP) from silver nitrate (AgNO3) as additives. The pre-treatment of PVA was performed in three steps, i.e., mixing PVA/AgNO3, electrospinning, and iodination. The interaction of PVA and AgNO3 was assessed by FTIR, and SEM was used to characterize the electro-spun fibers prior and after iodination; Raman spectrophotometer was carried out to confirm the yield of carbon fibers. There was reduction in oxygen groups (3000-3800 cm-1) and emergence of -C=O (1100 cm-1) and -C=C- (1627 cm-1) functional groups, indicating formation of carbon layers. Based on the DT/GA results, the silver nanoparticles reduce the need of high temperature with optimum carbonization at 350 °C and lead to the formation of more regular graphene layers. Graphene layers with a size distribution of 0.438 nm and well-organized structures were successfully formed, and the Raman shifting showed higher intensities of G and G' bands in the presence of Ag. Based on DT/GA results, the yield of carbon fibers with iodinated PVA fibers and SNP as additive had higher rates around 800 µg/min, reaching 33% at 500 °C. Thus, it is demonstrated that iodinated PVA/AgNO3 samples can significantly improve carbon fiber yield at low temperatures.

Antimicrobial and antihemolytic properties of a CNF/AgNP-chitosan film: A potential wound dressing material.

Cellulose nanofibers (CNFs), chitosan, and silver nanoparticles (AgNPs) are widely used to enhance the active functions and antibacterial properties of wound dressings. This study was conducted to prepare CNF/AgNP-chitosan using a straight incorporation method and to assess its antimicrobial activity. CNFs were isolated from oil palm empty fruit bunches (OPEFBs) using the pulping method and acid hydrolysis. AgNPs were synthesized using a green synthesis method. The wound dressing was produced by mixing a 10% CNF solution in LiCl/DMAc and AgNP-chitosan in a glass plate with various ratios of CNF/AgNP-chitosan, i.e., 100:0, 80:20, 60:40, and 50:50. UV-visible and TEM analyses were conducted to confirm the formation of AgNPs and CNFs at the nanoscale. The results showed particles with an absorption wavelength of 435 nm and spherical shapes. Based on the calculation using ImageJ software, the diameters of CNFs were approximately 50 nm, and the lengths were several micrometers. FTIR was used to analyze the chemical bonding of AgNP-chitosan and the incorporated AgNP-chitosan in CNFs. Based on the XRD analysis, the presence of AgNPs did not affect the crystallinity of the CNFs. SEM images showed that the addition of AgNPs resulted in the stretching of CNF pores on the pads. Thermal degradation of the film increased with the addition of AgNP-chitosan by up to 40%. Antimicrobial tests and hemocompatibility tests showed that the formed CNF/AgNP-chitosan film successfully inhibited bacterial growth and was classified as a nonhemolytic material; thus, its potential as a wound dressing should be further studied.

Characterization of Bacterial Cellulose-Based Wound Dressing in Different Order Impregnation of Chitosan and Collagen.

Bacterial cellulose (BC), chitosan (Chi), and collagen (Col) are known as biopolymers which have met some properties that are required as wound dressing. This study focused on investigating the fabrication of BC-based wound dressing with chitosan and collagen, since chitosan has red blood cells binding and anti-bacterial properties, while collagen can support cell and tissue growth for skin wounds. The BC-based wound dressing was prepared by impregnating BC fibers in the chitosan and/or collagen solution for 24 h. FTIR was used to confirm the intermolecular interaction of amine and hydroxyl group of chitosan and/or collagen in BC-based wound dressing. Furthermore, the XRD diffractogram of the wound dressing show broader peaks at 14.2°, 16.6°, and 22.4° due to the presence of chitosan and collagen molecules in BC fibers. These results were then supported by SEM images which confirmed that chitosan and collagen were well penetrated into BC fibers. TGA curves revealed that BC/Chi/Col has better thermal properties based on the Tmax compare to BC/Col/Chi. Feasibility of the mats to be applied as wound dressing was also supported by other tests, i.e., water content, porosity, and hemocompatibility, which indicates that the wound dressing is classified as nonhemolytic materials. However, BC/Col/Chi was considered a more potential wound dressing to be applied compared to BC/Chi/Col since it has larger pores and showed better antibacterial properties (larger zones of inhibition) against S. aureus and E. coli via disk diffusion tests.

Fabrication and In-Vivo Study of Micro-Colloidal Zanthoxylum acanthopodium-Loaded Bacterial Cellulose as a Burn Wound Dressing.

Bacterial cellulose (BC) is a biopolymer commonly used for wound dressing due to its high biocompatible properties either in-vitro or in-vivo. The three-dimensional fiber structure of BC becomes an advantage because it provides a template for the impregnation of materials in order to improve BC's properties as a wound dressing, since BC has not displayed any bioactivity properties. In this study, micro-colloidal Zanthoxylum acanthopodium (MZA) fruit was loaded into BC fibers via an in-situ method. Z. acanthopodium is known to have anti-inflammatory, antioxidant and antimicrobial activities that can support BC to accelerate the wound healing process. The FTIR, XRD and SEM analysis results showed that the loading process of MZA and the composite fabrication were successfully carried out. The TGA test also showed that the presence of MZA in BC fibers decreased Tmax composite from BC, from 357.8 to 334.5 °C for BC-MZA3. Other aspects, i.e., water content, porosity, hemocompatibility and histology studies, also showed that the composite could potentially be used as a wound dressing.

Isolation and Characterisation of Cellulose Nanofibre and Lignin from Oil Palm Empty Fruit Bunches.

A study on isolation and characterisation of cellulose nanofibre (CNF) and lignin was conducted to expand the application of CNF and lignin from oil palm biomass. CNF was extracted by steam explosion and the by-product was precipitated to obtain lignin by using the soda-pulping method. The concentrations of NaOH used for CNF by-product precipitation were 2%, 4%, and 6%. The morphology of CNF and lignin was characterised using scanning electron microscopy (SEM). The nanofibre of CNF with dimension between 50 nm and 100 nm was investigated using transmission electron microscopy (TEM). The functional group was observed using Fourier-transform infrared (FTIR) spectroscopy, showing that CNF had the structure of cellulose-I. In addition, the chemical structures of isolated and commercial lignin were analysed using 1H-NMR spectrometry. CNF had a 72% crystallinity index characterised by X-ray diffraction (XRD), while lignin showed an amorphous form. The characterisation of isolated lignin was compared with commercial lignin. The two lignins had similar particle size distribution from 1 to 100 µm. From UV-visible analysis, the lignin had aromatic rings/non-conjugated phenolic groups. The morphology of isolated lignin was rough and flaky. Commercial lignin was in powder form with near-spherical morphology. Thermogravimetric analysis (TGA) of CNF showed 30% of residue at 600 °C. The results showed a simple method to isolate CNF and lignin from oil palm empty fruit bunches.

Mechanical and thermal properties of bacterial-cellulose-fibre-reinforced Mater-Bi(®) bionanocomposite.

The effects of the addition of fibres of bacterial cellulose (FBC) to commercial starch of Mater-Bi(®) have been investigated. FBC produced by cultivating Acetobacter xylinum for 21 days in glucose-based medium were purified by sodium hydroxide 2.5 wt % and sodium hypochlorite 2.5 wt % overnight, consecutively. To obtain water-free BC nanofibres, the pellicles were freeze dried at a pressure of 130 mbar at a cooling rate of 10 °C min(-1). Both Mater-Bi and FBC were blended by using a mini twin-screw extruder at 160 °C for 10 min at a rotor speed of 50 rpm. Tensile tests were performed according to ASTM D638 to measure the Young's modulus, tensile strength and elongation at break. A field emission scanning electron microscope was used to observe the morphology at an accelerating voltage of 10 kV. The crystallinity (T c) and melting temperature (T m) were measured by DSC. Results showed a significant improvement in mechanical and thermal properties in accordance with the addition of FBC into Mater-Bi. FBC is easily incorporated in Mater-Bi matrix and produces homogeneous Mater-Bi/FBC composite. The crystallinity of the Mater-Bi/FBC composites decrease in relation to the increase in the volume fraction of FBC.

Investigation into the structural, morphological, mechanical and thermal behaviour of bacterial cellulose after a two-step purification process.

Bacterial cellulose (BC) is a natural hydrogel, which is produced by Acetobacter xylinum (recently renamed Gluconacetobacter xylinum) in culture and constitutes of a three-dimensional network of ribbon-shaped bundles of cellulose microfibrils. Here, a two-step purification process is presented that significantly improves the structural, mechanical, thermal and morphological behaviour of BC sheet processed from these hydrogels produced in static culture. Alkalisation of BC using a single-step treatment of 2.5 wt.% NaOH solution produced a twofold increase in Young's modulus of processed BC sheet over untreated BC sheet. Further enhancements are achieved after a second treatment with 2.5 wt.% NaOCl (bleaching). These treatments were carefully designed in order to prevent any polymorphic crystal transformation from cellulose I to cellulose II, which can be detrimental for the mechanical properties. Scanning electron microscopy and thermogravimetric analysis reveals that with increasing chemical treatment, morphological and thermal stability of the processed films are also improved.