ABSTRACT
The global COVID-19 pandemic has triggered a huge demand for the protective nonwovens. However, the main raw material of nonwovens comes from petroleum, and the massive consumption of petroleum-based polymers brings great pressure to ecosystem. Therefore, it is significant to develop biodegradable protective barrier products. In this work, a polylactic-based composite (a tri-layer nonwovens composed of spunbond, meltblown and spunbond, SMS) was prepared and applied for protective apparel. The surface morphology and chemical changes of the fibers were characterized and analyzed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). The liquid contact angle and permeability, breathability and moisture permeability, frictional charge and mechanical strength of the samples were evaluated and compared. The samples degradability was also recorded. The results demonstrate that the optimum formula for anti-fouling treatment on SMS is F-30. The treated fabric possesses superior liquid repellency and anti-permeability, with contact angles of water and alcohol at 128° and 115° respectively, while the alcohol repellent grade reaches level 7. The treated sample has less strength loss but exhibits favorable breathability, moisture permeability and anti-static properties, which can meet the requirements of protective apparels. After fluorine resin coating, the composite still provide excellent degradation performance, and the weight loss rate reaches more than 80% after 10 days water degradation. These results provide new insights for the application of PLA-based SMS in biodegradable protective apparel. © 2023 The Textile Institute.
ABSTRACT
The establishment of novel disruptive technologies represents a common requirement for the sustainable development as reported in the 2030 agenda established by United Nations. As demonstrated by the Covid-19 pandemic, and furtherly highlighted by the current global challenges, i.e. precision agriculture, decentralized testing, personalized medicine, the field of portable devices is growing day-by-day. Relatively to the electrochemical portable strips, globally represented by glucose strips for diabetes patients, the use of plastic-based products is still very high. In this work, two bacterial polymers have been deeply characterized and compared with the gold standard polyester that is the most used material to produce printed electrochemical strips. In particular, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV with micro-fibrillated cellulose (MFC), namely PHBV/MFC, have been produced with different porosities and have been morphologically, mechanically and electrochemically characterized. Scanning electron microscopy, contact angle, tensil tests, cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, stripping voltammetry and chronoamperometry have been used to evaluate and confirm the suitability of PHBV-based substrates for future sustainable application in the (bio)electroanalytical field. In particular these novel substrates have been applied towards the development of two sensing platforms, namely iron ions and organophosphate pesticides. As shown, in comparison with the gold standard polyester for sensors and biosensors development, the use of PHBV-based substrates allowed to reach similar detection limit and repeatability. In particular, iron ions were detected down to 140 and 150 ppb and dichlorvos was detect with an inhibition biosensor down to 0.4 and 0.5 ppb, respectively for PHBV and PHBV/MFC. These novel substrates may represent a starting point towards the development of sustainable platforms for decentralized applications. • PHBV-based materials are 100% bio-compatible and bio-degradable. • Cellulose merging is able to provide new functionalities. • Polyester-based substrates can be replaced by more sustainable ones. • A novel starting point to make sustainable electrochemical (bio)sensors. • Facile detection of iron ions and organophosphate as the case of study. [ FROM AUTHOR]
ABSTRACT
This article presents current possibilities of using polyester-based materials in hard and soft tissue engineering, wound dressings, surgical implants, vascular reconstructive surgery, ophthalmology, and other medical applications. The review summarizes the recent literature on the key features of processing methods and potential suitable combinations of polyester-based materials with improved physicochemical and biological properties that meet the specific requirements for selected medical fields. The polyester materials used in multiresistant infection prevention, including during the COVID-19 pandemic, as well as aspects covering environmental concerns, current risks and limitations, and potential future directions are also addressed. Depending on the different features of polyester types, as well as their specific medical applications, it can be generally estimated that 25-50% polyesters are used in the medical field, while an increase of at least 20% has been achieved since the COVID-19 pandemic started. The remaining percentage is provided by other types of natural or synthetic polymers; i.e., 25% polyolefins in personal protection equipment (PPE).
ABSTRACT
When approached to write this piece, the author was overwhelmed with the magnitude of problems and deep challenges faced by school libraries in South Africa. As librarians, we resort to literature to make sense of the situation. Secondly, as we conduct activities of School Libraries' and Youth Services Interest Group under Library and Information Association of South Africa we can bear testimony. This makes sense, and one paragraph from the Government's literature could not be ignored. The adopted curriculum assumes all learners are competent and information literate. The seeming lack of political will to create functional school libraries cannot be ruled out. Since democracy, only 25, 82% of schools have libraries.
ABSTRACT
Messenger RNA (mRNA) has generated great attention due to its broad potential therapeutic applications, including vaccines, protein replacement therapy, and immunotherapy. Compared to other nucleic acids (e.g., siRNA and pDNA), there are more opportunities to improve the delivery efficacy of mRNA through systematic optimization. In this report, we studied a high-throughput library of 1200 functional polyesters for systemic mRNA delivery. We focused on the chemical investigation of hydrophobic optimization as a method to adjust mRNA polyplex stability, diameter, pKa, and efficacy. Focusing on a region of the library heatmap (PE4K-A17), we further explored the delivery of luciferase mRNA to IGROV1 ovarian cancer cells in vitro and to C57BL/6 mice in vivo following intravenous administration. PE4K-A17-0.2C8 was identified as an efficacious carrier for delivering mRNA to mouse lungs. The delivery selectivity between organs (lungs versus spleen) was found to be tunable through chemical modification of polyesters (both alkyl chain length and molar ratio in the formulation). Cre recombinase mRNA was delivered to the Lox-stop-lox tdTomato mouse model to study potential application in gene editing. Overall, we identified a series of polymer-mRNA polyplexes stabilized with Pluronic F-127 for safe and effective delivery to mouse lungs and spleens. Structure-activity relationships between alkyl side chains and in vivo delivery were elucidated, which may be informative for the continued development of polymer-based mRNA delivery.
ABSTRACT
BACKGROUND: High levels of oxidants, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), are typical characteristics of an inflammatory microenvironment and are closely associated with a various inflammatory pathologies, eg, cancer, diabetes, atherosclerosis, and neurodegenerative diseases. Therefore, the delivery of anti-inflammatory drugs by oxidation-responsive smart systems would be an efficient anti-inflammatory strategy that benefits from the selective drug release in an inflammatory site, a lower treatment dose, and minimizes side effects. PURPOSE: In this study, we present the feasibility of an oxidation-sensitive PEGylated alternating polyester, methoxyl poly(ethylene glycol)-block-poly(phthalic anhydride-alter-glycidyl propargyl ether) (mPEG-b-P(PA-alt-GPBAe)), as novel nanocarrier for curcumin (CUR), and explore the application in anti-inflammatory therapy. METHODS: The copolymers used were obtained by combining a click reaction and a ring-opening-polymerization method. CUR was loaded by self-assembly. The in vitro drug release, cytotoxicity toward RAW 264.7 cells and cellular uptake were investigated. Furthermore, the anti-inflammatory effects of CUR-loaded polymeric nanoparticles (NPs-CUR) were investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and tested in a murine model of ankle inflammation. RESULTS: Fast drug release from NPs-CUR was observed in trigger of 1 mM H2O2 in PBS. Compared with NPs and free drugs, the significant anti-inflammatory potential of NPs-CUR was proven in activated RAW 264.7 cells by inhibiting the production of TNF-α, IL-1ß, and IL-6 and increasing the level of an anti-inflammatory cytokine IL-10. Finally, a local injection of NPs-CUR at a dose of 0.25 mg/kg suppressed the acute ankle inflammatory response in mice by histological observation and further reduced the expression of pro-inflammatory cytokines in the affected ankle joints compared to that of free CUR. CONCLUSION: Both the significant in vitro and in vivo anti-inflammatory results indicated that our oxidation responsive polymeric nanoparticles are promising drug delivery systems for anti-inflammatory therapy.