Development and Characterization of Photoinduced Acrylamide-Grafted Polylactide Films for Biomedical Applications

Surface grafting of biodegradable/biocompatible polylactide (PLA) films by a UV-assisted reaction has been developed by employing a hydrophilic acrylamide (Am) monomer, an N,N′-methylenebisacrylamide (MBAm) cross-linker, and a camphorquinone (CQ)/N,N′-dimethylaminoethylmethacrylate (DMAEMA) photoinitiator/coinitiator system. The accomplishment of the process is confirmed by FTIR and XPS analyses. Physicochemical changes of the grafted PLA films are evaluated in terms of chemical structures, radiation-induced degradation followed by crystallization, morphology, thermal properties, and mechanical behavior. The results reveal that a low degree of PLA degradation through chain scission is observed in both blank and grafted PLA films. This generates more polar chain ends that can further induce crystallization. Results from contact angle measurements indicate that the grafted films have higher hydrophilicity and pH-responsive behavior. The incorporation of PAm on the film’s surface and the induced crystallization lead to improvements in certain aspects of mechanical properties of the films. The materials have high potential for use in biomedical and environmental applications, such as cell culture substrates or scaffolds or pH-sensitive absorbents

A Preliminary Review of Poly(lactic acid)-based Biodegradable Foam and its Techno-economic Model

Biodegradable polymers using renewable resources with properties that are comparable to bio-based and fossil-based polymer materials at a comparable cost have been studied and developed in an effort to solve environmental issues, especially expanded polystyrene. One potential raw main material to replace EPS is poly(lactic acid), a synthetic polymer made from lactic acid, which is made by fermenting organic materials like sweetcorn, rice, soya, potatoes, or whey. It is used in food and non-food packaging, drug-controlled release, agriculture, automotive, and electronic accessories. Foaming is vital in developing lighter, more cost-effective materials that may be utilized for a range of purposes due to their general features, such as lightweight, good heat, more ductile (elastic), and excellent energy absorption (impact resistance). In this review, different types of foaming processes and their process parameters are focused at. It was written following the procedures outlined in the PRISMA2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines for conducting a review to reports and evaluating a wide variety of interventions. Furthermore, a sustainable material should focus on the efficacy of its resource consumption and the economic feasibility of the product it creates. An economic feasibility study is also provided in this article aims to evaluate how much profit a production plant can make. The techno-economic model developed in this study yielded a profit on sales of 69.69% and an internal rate of return of 44.0%. Techno-economic modeling favored the commercial use of poly(lactic acid)-based biodegradable foam based on its positive net present value, short payback period, and high internal rate of return

Preparation and Properties of Electrospun Fibers of Titanium Dioxide-Loaded Polylactide/Polyvinylpyrrolidone Blends

Nanofibers of polylactide (PLA)/polyvinylpyrrolidone (PVP) blends loaded with titanium dioxide (TiO2) particles have been prepared by an electrospinning technique. TiO2 particles are formed by sol-gel mechanisms from titanium (IV) iso-propoxide (TTIP) precursor. Effect of TiO2 formation rate on properties of the fibers are examined by adding iso-propyl alcohol (iPOH) to slow down the TiO2 precipitation process. The use of iPOH produces fiber mats consisting of slightly bigger and smoother filaments, but smaller-sized embedded TiO2 particles. Both materials show a distinct UV absorption characteristic of TiO2 at λmax 300 nm, which can be applied in catalytic applications. Degradation behaviors of the materials in phosphate buffer solutions have also been investigated. The materials have high potential for use as epoxidation catalysts for conversion of vegetable oils to polymeric building blocks and plasticizers.

Development of ammonia gas sensor based on Ni-doped reduce graphene oxide

The work aims to develop a simple and low cost ammonia gas sensor based on reduced graphene oxide (rGO). Reduced graphene oxide doped with nickel sulfate (NiSO4/rGO) was used as a sensing material. The sensor was fabricated by a simple drop-cast and spin-coat technique. The performance of the nickel-doped reduce graphene oxide were studied in terms of electrical changes as well as chemical interactions. It was found that after the fabricated sensor was exposed to ammonia vapour for 10 min, the average resistivity was increased to 43% from initial resistance and retained about 8% resistance change upon ammonia removal. The mechanism of the sensor reaction with the ammonia gas is also studied using Fourier Transform Infrared Spectroscopy (FTIR) and is discussed. This preliminary work may help develop the highly sensitive ammonia gas sensor

Biodegradable porous micro/nanoparticles with thermoresponsive gatekeepers for effective loading and precise delivery of active compounds at the body temperature

International audienceAbstract Stimuli-responsive controlled delivery systems are of interest for preventing premature leakages and ensuring precise releases of active compounds at target sites. In this study, porous biodegradable micro/nanoparticles embedded with thermoresponsive gatekeepers are designed and developed based on Eudragit RS100 (PNIPAM@RS100) and poly(N-isopropylacrylamide) via a double emulsion solvent evaporation technique. The effect of initiator types on the polymerization of NIPAM monomer/methylene-bis-acrylamide (MBA) crosslinker was investigated at 60 °C for thermal initiators and ambient temperature for redox initiators. The crosslinked PNIPAM plays a key role as thermal-triggered gatekeepers with high loading efficiency and precise release of a model active compound, Nile Blue A (NB). Below the volume phase transition temperature (T VPT ), the gatekeepers possess a swollen conformation to block the pores and store NB within the cavities. Above its T VPT , the chains rearrange, allowing gate opening and a rapid and constant release rate of the compound until completion. A precise “on–off” switchable release efficiency of PNIPAM@RS100 was demonstrated by changing the temperatures to 4 and 40 °C. The materials are a promising candidate for controlled drug delivery systems with a precise and easy triggering mechanism at the body temperature for effective treatments

Development of ammonia gas sensor based on Ni-doped reduce graphene oxide

The work aims to develop a simple and low cost ammonia gas sensor based on reduced graphene oxide (rGO). Reduced graphene oxide doped with nickel sulfate (NiSO4/rGO) was used as a sensing material. The sensor was fabricated by a simple drop-cast and spin-coat technique. The performance of the nickel-doped reduce graphene oxide were studied in terms of electrical changes as well as chemical interactions. It was found that after the fabricated sensor was exposed to ammonia vapour for 10 min, the average resistivity was increased to 43% from initial resistance and retained about 8% resistance change upon ammonia removal. The mechanism of the sensor reaction with the ammonia gas is also studied using Fourier Transform Infrared Spectroscopy (FTIR) and is discussed. This preliminary work may help develop the highly sensitive ammonia gas sensor

Slow Release of Menthol Using Sorbents Developed from Microwave Graphene Oxide

Menthol is a key ingredient in many of the traditional Thai aroma products such as potpourri and herbal air freshener. However, it suffers from the rapid evaporation and sublimation loss. In this work, microwave graphene oxide (mGO) has been prepared as sorbent and tested for the slow release of menthol. Menthol was loaded into microwave graphene oxide at loading ratios of 1:0.5 and 1:1. The release performance of the mGO as compared to traditional essential oil reed diffuser and the pure menthol was studied by monitoring the menthol weight loss at the temperature of 80°C until all of the menthol evaporated using thermogravimetric analysis. It was found that mGO can significantly slow down the menthol release rate compared to that of the pure menthol by up to eight times slower. The interaction and adsorption mechanism of the menthol-loaded microwave graphene oxide was also studied using Fourier Transform Infrared Spectroscopy (FTIR) which indicates that menthol adsorbs strongly onto the mGO leading to the slow release rate

Preparation of Eumelanin-Encapsulated Stereocomplex Polylactide Nano/Microparticles for Degradable Biocompatible UV-Shielding Products

The role of eumelanin as a natural pigment in protecting human skin from ultraviolet (UV) light has drawn vast interest in the research and industrial community. Encapsulation of the compound by various shell materials has been extensively studied to optimize and prolong its shielding efficiency from UV penetration through the skin. Polylactide (PLA)-based copolymers have been widely used in the encapsulation of various active compounds due to their biocompatibility and biodegradability that facilitate sustained release of the active compounds. In this work, stereocomplex PLA (sc-PLA) derived from mixtures of poly(D-lactide-caprolactone-D-lactide), P(DLA-b-CL-b-DLA), a triblock copolymer with linear poly(L-lactide), and PLLA are employed to encapsulate eumelanin by an oil-in-water emulsion (O/W) technique. The effect of eumelanin distribution in PLA’s enantiomers and ultrasonication on the physicochemical properties, encapsulation efficiency, and release behavior of the nano/microparticles were evaluated. The potential application of the resulting particles for sunscreen products was assessed in terms of UV absorbance and in vitro sun protection factor (SPF). The nano/microparticles show a hollow spherical structure, whose size can be controlled by ultrasonication. The distribution of eumelanin and the ultrasonication process play a key role in the growth of sc-PLA and the crystalline structure of the particles. The highest encapsulation efficiency of 46.6% was achieved for sc-PLA2U particles. The high content of eumelanin and the hollow structure with a large surface area lead to improvement in the UV absorbance and sunscreen performance of the particles, as revealed by the increase in the SPF value from 9.7 to 16.5. The materials show high potential for various applications, especially in cosmetic and pharmaceutical fields, as UV-shielding products

Facile Fabrication of Oxygen‐Enriched MXene‐Based Sensor and Their Ammonia Gas‐Sensing Enhancement

Abstract Various sensing materials have been demonstrated to increase the precision of sensing technology. Nevertheless, this complicates the fabrication process for materials integration to obtain devices that can simultaneously accommodate various gas detectors, like electronic nose. The study here focuses on exploring the sensing response of different functionalization of specific sensing materials to provide an alternative way to achieve selective response to multiple gases. Triethoxysilylpropyl succinic anhydride silane (TESPSA) was introduced on 2D material MXene‐Ti3C2Tx to form carboxylic acid terminated MXene (COOH‐Ti3C2Tx) and alternately coated with polyaniline (COOH‐Ti3C2Tx/PANI). This modification doubled up the gas binding sites and improved the binding strength of the Ti3C2Tx surface to NH3 gas molecules. The 5CC‐COOH‐Ti3C2Tx/PANI sensor prepared from five coating cycles showed the highest sensitivity (214.70 %) with fast gas response rate at 80 ppm NH3 (1.75 % s‐1). Therefore, the different signal responses from specific functionalization of the same sensing material functionalization will allow the possible sensor array fabrication to achieve fingerprint‐like sensing map recognition in the presence of mixed gases