Electrospun microporous gelatin–polycaprolactone blend tubular scaffold as a potential vascular biomaterial

The work reported involved the fabrication of an electrospun tubular conduit of a gelatin and polycaprolactone (PCL) blend as an adventitia‐equivalent construct. Gelatin was included as the matrix for increased biocompatibility with the addition of PCL for durability. This is contrary to most of the literature available for biomaterials based on blends of gelatin and PCL where PCL is the major matrix. The work includes the assiduous selection of key electrospinning parameters to obtain smooth bead‐free fibres with a narrow distribution of pore size and fibre diameter. Few reports elucidate the optimization of all electrospinning parameters to fabricate tubular conduits with a focus on obtaining homogeneous pores and fibres. This stepwise investigation would be unique for the fabrication of gelatin–PCL electrospun tubular constructs. The fabricated microfibrous gelatin–PCL constructs had pores of size ca 50–100 μm reportedly conducive for cell infiltration. The measured value of surface roughness of 57.99 ± 17.4 nm is reported to be favourable for protein adhesion and cell adhesion. The elastic modulus was observed to be similar to that of the tunica adventitia of the native artery. Preliminary in vitro and in vivo biocompatibility tests suggest safe applicability as a biomaterial. Minimal cytotoxicity was observed using MTT assay. Subcutaneous implantation of the scaffold demonstrated acute inflammation which decreased by day 15. The findings of this study could enable the fabrication of smooth bead‐free microfibrous gelatin–PCL tubular construct as viable biomaterial which can be included in a bilayer or a trilayer scaffold for vascular tissue engineering. © 2019 Society of Chemical Industry     

Isolation of antimicrobial agent from the marine algae Cystoseira hakodatensis

Cystoseira hakodatensis is an unutilised brown algae belonging to family Sargassaceae. A crude methanol extract from the algae showed inhibitory effects on the growths of Bacillus cereus and Bacillus licheniformis. To isolate the major antimicrobial agent, a sequential active‐guided isolation procedure was applied: liquid–liquid extraction, column chromatography and bio‐autography. A marked antimicrobial agent (active α) was isolated in hydrophobic fraction and was determined to phenolics without carbohydrates and proteins by phytochemical test. Regarding the antimicrobial potential, the isolated active α showed better inhibitory effects against B. cereus and B. licheniformis at 2 and 4 times of lower concentrations (62.5 and 31.3 μg mL^?1) in comparison with epigallocatechin gallate. These results showed that C. hakodatensis is a potential source of antimicrobial agent capable of preventing the growth of the two bacteria.     

Energy Recovery in Pressurized Hydraulic Networks

Water Resources Management - This paper aims to evaluate the possibility of using non-utilized hydraulic energy in urban water distribution systems. For this purpose, the viability and possible...     

Biodegradation of poly(lactic acid)—cassava bagasse composites produced by injection molding

Neat poly (lactic acid) (PLA) and PLA/cassava bagasse (CB) composites were used to produce seedling tubes by extrusion and injection molding. The tubes were buried in simulated soil, and their biodegradation was investigated by weight loss, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). After 180 days, the composites' biodegradation was higher than neat PLA material, and the higher the CB content, the higher the biodegradation, which caused fissures and voids in the material. The biodegradation of PLA/CB composites increased the phosphorus content in the soil after 180 days. Composites of PLA with CB, an abundant agro-industrial residue in Brazil, are promising because they can reduce the environmental impact due to CB's proper destination, and the composites' costs and biodegradation are faster than pure PLA material. Both the faster biodegradation of the tube and the higher P content are advantageous for seedling tubes.