Functionalised Hybrid Collagen-Elastin for Acellular Cutaneous Substitute Applications

Wound contracture, which commonly happens after wound healing, may lead to physical distortion, including skin constriction. Therefore, the combination of collagen and elastin as the most abundant extracellular matrix (ECM) skin matrices may provide the best candidate biomaterials for cutaneous wound injury. This study aimed to develop a hybrid scaffold containing green natural resources (ovine tendon collagen type-I and poultry-based elastin) for skin tissue engineering. Briefly, freeze-drying was used to create the hybrid scaffolds, which were then crosslinked with 0.1% (w/v) genipin (GNP). Next, the physical characteristics (pore size, porosity, swelling ratio, biodegradability and mechanical strength) of the microstructure were assessed. Energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FTIR) spectrophotometry were used for the chemical analysis. The findings showed a uniform and interconnected porous structure with acceptable porosity (>60%) and high-water uptake capacity (>1200%), with pore sizes ranging between 127 ± 22 and 245 ± 35 µm. The biodegradation rate of the fabricated scaffold containing 5% elastin was lower (<0.043 mg/h) compared to the control scaffold (collagen only; 0.085 mg/h). Further analysis with EDX identified the main elements of the scaffold: it contained carbon (C) 59.06 ± 1.36-70.66 ± 2.89%, nitrogen (N) 6.02 ± 0.20-7.09 ± 0.69% and oxygen (O) 23.79 ± 0.65-32.93 ± 0.98%. FTIR analysis revealed that collagen and elastin remained in the scaffold and exhibited similar functional amides (amide A: 3316 cm^-1, amide B: 2932 cm^-1, amide I: 1649 cm^-1, amide II: 1549 cm^-1 and amide III: 1233 cm^-1). The combination of elastin and collagen also produced a positive effect via increased Young's modulus values. No toxic effect was identified, and the hybrid scaffolds significantly supported human skin cell attachment and viability. In conclusion, the fabricated hybrid scaffolds demonstrated optimum physicochemical and mechanical properties and may potentially be used as an acellular skin substitute in wound management.

Ground improvement and its role in carbon dioxide reduction: a review

Environmental global issues affecting global warming, such as carbon dioxide (CO2), have attracted the attention of researchers around the world. This paper reviews and discusses the ground improvement and its contribution to reducing CO2 in the atmosphere. The approach is divided into three parts: the Streamlined Energy and Emissions Assessment Model (SEEAM), the replacement of soil stabilisation materials that lead to the emission of a large amount of CO2 with alternatives and mineral carbonation. A brief discussion about the first two is reviewed in this paper and a detailed discussion about mineral carbonation and its role in enhancing soil strength while absorbing a large amount of CO2. It is emphasised that natural mineral carbonation requires a very long time for a material to reach its full capacity to form CO2; as a result, different acceleration processes can be done from increasing pressure, temperature, the concentration of CO2 and the addition of various additives. In conclusion, it was found that magnesium is more attractive than calcium, and calcium is complicated in terms of strength behaviour. Magnesium has a larger capacity for CO2 sequestration and it has a greater potential to increase soil strength than calcium.

Rapid Evaluation and Optimization of Medium Components Governing Tryptophan Production by Pediococcus acidilactici TP-6 Isolated from Malaysian Food via Statistical Approaches

Tryptophan is one of the most extensively used amino acids in livestock industry owing to its effectiveness in enhancing the growth performance of animals. Conventionally, the production of tryptophan relies heavily on genetically modified Escherichia coli but its pathogenicity is a great concern. Our recent study demonstrated that a lactic acid bacterium (LAB), Pediococcus acidilactici TP-6 that isolated from Malaysian food was a promising tryptophan producer. However, the tryptophan production must enhance further for viable industrial application. Hence, the current study evaluated the effects of medium components and optimized the medium composition for tryptophan production by P. acidilactici TP-6 statistically using Plackett-Burman Design, and Central Composite Design. The optimized medium containing molasses (14.06 g/L), meat extract (23.68 g/L), urea (5.56 g/L) and FeSO4 (0.024 g/L) significantly enhanced the tryptophan production by 150% as compared to the control de Man, Rogosa and Sharpe medium. The findings obtained in this study revealed that rapid evaluation and effective optimization of medium composition governing tryptophan production by P. acidilactici TP-6 were feasible via statistical approaches. Additionally, the current findings reveal the potential of utilizing LAB as a safer alternative tryptophan producer and provides insight for future exploitation of various amino acid productions by LAB.

Isolation, Purification and Characterization of Antioxidative Bioactive Elastin Peptides from Poultry Skin

Muscle-based by-products are often undervalued although commonly reported having a high amount of natural bioactive peptides. In this study, elastin was isolated from the protein of broiler hen skin while its hydrolysate was prepared using Elastase. Assessment of antioxidative properties of elastin-based hydrolysate (EBH) was based on three different assays; 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical and metal chelating ability. The EBH was purified further using ultrafiltration, gel filtration and Reverse- Phase High-Performance Liquid Chromatography (RP-HPLC). The IC50 of ABTS radical activities for EBH were decreased as EBH further purified using ultrafiltration (EBH III; 0.66 mg/mL)>gel filtration (EB-II; 0.42 mg/mL)>RP-HPLC (EB-II4; 0.12 mg/mL). The sequential identification of the peptide was done by matrix-assisted laser desorption/ ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/ TOF-MS) of the potent fractions obtained from RP-HPLC (EB-II4). The presence of hydrophobic amino acids (Val and Pro) in the peptide sequences could potentially contribute to the high antioxidant activity of EBH. The sequences GAHTGPRKPFKPR, GMPGFDVR and ADASVLPK were identified as antioxidant peptides. In conclusion, the antioxidative potential from poultry skin specifically from elastin is evident and can be explored to be used in many applications such as health and pharmaceutical purposes.