Glycolate Research Articles

A PLGA/Silk Fibroin Nanofibre Membrane Loaded with Natural Flavonoid Compounds Extracted from Green Cocoons for Wound Healing.

The use of biodegradable materials combined with natural metabolites in wound dressings has received much attention. Flavonoids (FLs) from green cocoons, as metabolites, have antibacterial, antioxidant, anti-inflammatory, and other pharmacological effects. In this study, composite membranes of FL-loaded polylactic glycolic acid (PLGA)/silk fibroin (SF) were prepared by an electrospinning method. The prepared membranes, including SF, exhibited a good slow-release effect and cytocompatibility. An in vitro evaluation of the FL-loaded PLGA/SF membranes demonstrated good antioxidant, antibacterial, and anti-inflammatory properties. Animal experiments showed that the wound healing rate of PLGA/SF-2.5FL membranes within 15 days was 97.3%, and that of the control group was 72.5%. The PLGA/SF-2.5FL membranes shortened the inflammatory period of a full-layer wound model and promoted skin regeneration and wound healing by downregulating expression of the pro-inflammatory cytokines IL-1β and TNF-α and promoting expression of the growth factors VEGF, TGF-β, and EGF. In summary, the PLGA/SF-2.5FL composite nanofibre membrane with anti-inflammatory properties is an ideal wound dressing to promote acute wound healing.

Structure and Kinetics of Organic Acid Radicals Formed in Reaction with •OH Radicals.

The study investigated •OH-derived radicals from certain organic acids employed in nuclear fuel processing and separation using EPR spectroscopy and quantum chemistry methods. Hydroxyl radicals were generated through a Fenton-like reaction within the EPR resonator under both acidic and basic conditions, allowing for the detection of neutral and radical anions, respectively. The spectral assignment and analysis were conducted using a combination of literature data and quantum chemical calculations employing DFT theory with B3LYP or LPBE functionals and the L2a_3 basis set. The reaction of the •OH radical with lactic and glycolic acids yielded primary C-centered radicals through hydrogen abstraction from these acids. In contrast, the •OH radical exclusively generated secondary radicals from oxalic acid, whereas for citric acid, it resulted in both primary and secondary species induced by decarboxylation. The EPR spectrum of acetohydroxamic acid, upon reaction with the •OH radical, displayed a complex pattern featuring primary •N-type and N-O•-type radicals. The decay pathways of the generated radicals were primarily attributed to radical-radical reactions, with the extracted reaction rate constants generally falling within the typical range observed for such reactions. The EPR parameters calculated for potential radicals using B3LYP and LPBE functionals with L2a_3 basis set demonstrated good accuracy for neutral radicals, albeit requiring minor adjustments for radical anions.

Screening and fermentation of high-yield glycolic acid strains

Glycolic acid is an important chemical product widely used in various fields, including cosmetics, detergents, textiles, and more. Currently, microbial production of glycolic acid has disadvantages such as poor genetic stability, low yield, and high cost. Additionally, whole-cell catalytic production of glycolic acid typically requires the addition of relatively expensive sorbitol as a carbon source, which limits its industrial production. To develop an industrially applicable method for glycolic acid production, this study used ethylene glycol as a substrate to screen the glycolic acid-producing strains through whole-cell catalysis, obtaining a Rhodotorula sp. capable of producing glycolic acid. The strain was then subjected to UV mutagenesis and high throughput screening, and the positive mutant strain RMGly-20 was obtained. After optimization in shake flasks, the glycolic acid titer of RMGly-20 reached 17.8 g/L, a 10.1-fold increase compared to the original strain. Using glucose as the carbon source and employing a fed-batch culture in a 5 L fermenter, strain RMGly-20 produced 61.1 g/L of the glycolic acid. This achievement marks the preliminary breeding of a genetically stable glycolic acid-producing strain using a cheap carbon source, providing a new host for the biosynthesis of glycolic acid and promoting further progress toward industrial production.

The crystal engineering of 3d-metal with two tetrazole-phenyl-carboxylate linkers and multiple post-synthetic metal exchange

Ligand with mixed-groups contributes to the construction of special structure motif with novel properties, yet it is challenging to understand and regulate the competitive coordination of different functional groups toward metal ions. Herein, the crystal engineering for MOF construction from two linear di-topic linkers of 4-(1H-tetrazol-5-yl)benzoic acid (H2tzba) and the longer 4′-(1H-tetrazol-5-yl)-[1,1′-biphenyl]-4-carboxylic acid (H2tzbba) featuring dual groups of phenyl-carboxylate and tetrazole, with three typical 3d metal ions (Mn2+, Fe2+ and Zn2+) were investigated. A series of five new MOFs, that are [Mn3(tzba)3(dmf)4]·11dmf (1, dmf = N,N-Dimethylformamide), [Mn(tzba)(H2O)] (2), [Zn2(tzba)2(dmf)]·0.5dmf (3), [Fe2(tzba)2(dmf)]·0.5dmf (4) and [Zn2(tzbbz)(gac)(dmf)2]·1.5dmf (5), were synthesized under solvothermal reactions. The modified solvent template and temperature effects lead to 3D framework of 1 (dmf solution under 433 K) with [Mn3(tz)3(COO)3] nodes and 1D hexagonal channels, while the 2 (water solution under 373 K) posssesses compact pillared-layer motif from [Mn2(tz)2] nodes. Under changed metal salt reactents but same solvent of dmf, the generated 3 and 4 have isoreticular and porous pillared-layer structure constituted of [M2(COO)2] nodes. The use of tzbba coupled with a crucial auxiliary ligand of glycollic acid, leads to 5 as porous pillared-layer MOFs with 1D rounded channels. The porous flexible skeleton of 1 constructed from [Mn3] node with four coordinated dmf facilitates post-synthetic metal exchange of the Mn2+ by radius similar metal ions following priority of Cu2+ < Zn2+ < Ni2+< Co2+, with maximum exchange percentage ranging from 17 % to 69 %. Time dependent ICP-AES analysis revealed the quite wide feasible solvents for post-synthetic metal exchange, as well as the fine control on substituting degree based on soaking temperature and time. Particularly, the compatible introduce of four different metal ions support the potential of preparing bi-, tri-, tetra- and penta- metal MOF crystals, that can not be obtained by traditional solvothermal reactions.

Engineering p-d orbital hybridization in PdSb bimetallene for energy-saving H2 production parallel upgrade plastic waste

The electrochemical conversion of PET-derived ethylene glycol into high-quality chemicals parallel energy-saving H2 production is an optimal solution to the serious environmental pollution of plastics. In this paper, p-d orbital hybrid PdSb bimetallene with defect-rich crimped surface is synthesized by a one-step solvent approach. PdSb bimetallene exhibits excellent electrocatalytic performance in ethylene glycol and PET hydrolysate oxidation attributed to the unconventional p-d orbital hybridization feature and metallene structure. PdSb bimetallene shows better properties than Pd metallene and commercial Pd black catalysts under ethylene glycol conditions and PET hydrolysate. Besides PdSb bimetallene can oxidize ethylene glycol to produce the valuable product glycolic acid with high Faradaic efficiency and selectivity. Besides, PdSb bimetallene can oxidize PET-derived ethylene glycol into glycolic acid with high selectivity in EGOR||HER system. This study provides insights into the synthesis of metallene with p-d orbital hybridization properties, coupled with energy-saving H2 production parallel upgrade plastic waste.

Synthesis of 3D hierarchical flower-like calcium sulfate microspheres for cadmium removal from wastewater

Novel three-dimensional hierarchical flower-like calcium sulfate microspheres (CSMs) were successfully prepared with the assistance of polyethylene glycol, trisodium citrate, and polyacrylic acid. The CSMs were monodispersed as flower-like microspheres constructed from interspersed nanosheets. Their average diameter and Brunauer–Emmett–Teller specific surface area were 15 μm and 16.09 m2/g, respectively. The prepared CSMs were employed as adsorbents in cadmium (Cd(II)) removal from wastewater and their Cd(II) adsorption performances were analyzed. The adsorption kinetic data were best fitted to the pseudo-first-order kinetic model and the experimental isotherm data were precisely fitted to the Freundlich isothermal model. The maximum adsorption capacity of the CSMs could reach up to 18.13 mg/g at 293 K under neutral conditions, affirming the potential utility of the CSMs in Cd(II) removal from wastewater.

Fabrication and Photovoltaic Conversion Performances of Imidazolyl and Fumaric Acid Composite Langmuir-Blodgett Membranes.

Novel organic small molecule structures have received increasing attention in the preparation of multifunctional thin film materials and have become the subject of research in many cutting-edge directions. In this work, imidazolyl and transbutylene glycolic acid molecules and dye molecules were designed and prepared as composite films by supramolecular self-assembly in the LB technique, and their morphological features and spectral properties were analyzed. The results showed that the prepared LB films presented different aggregation states. In addition, their photoelectrochemical properties, on ITO sheets were tested, all of which showed good optoelectronic properties, and their binding energies, structure optimization, and electrostatic potentials were theoretically calculated by DFT simulations, which proved that the prepared films have good optoelectronic properties, and have the potential to become optoelectronic multifunctional ultrathin film devices.

Evaluating the antibacterial, antibiofilm, and anti-toxigenic effects of postbiotics from lactic acid bacteria on Clostridium difficile.

The most common cause of healthcare-associated diarrhea is Clostridium difficile infection (CDI), which causes severe and recurring symptoms. The increase of antibiotic-resistant C. difficile requires alternate treatments. Postbiotics, metabolites produced by probiotics, fight CDI owing to their antibacterial capabilities. This study aims to evaluate the antibacterial, antibiofilm, and anti-toxigenic potential of postbiotics in combating CDI. GC-MS evaluated postbiotics from Bifidobacterium bifidum and Lactobacillus plantarum. Disk diffusion and broth microdilution determined C. difficile antibacterial inhibition zones and MICs. Microtiter plates assessed antibiofilm activity. MTT assay evaluated postbiotics anti-viability on HEK293. ELISA testing postbiotic detoxification of toxins A and B. Postbiotics were examined for tcdA and tcdB genes expression using real-time PCR. The most identified B. bifidum and L. plantarum postbiotic compounds were glycolic acid (7.2%) and butyric acid (13.57%). B. bifidum and L. plantarum displayed 13 and 10 mm inhibition zones and 2.5 and 5 mg/ml MICs against C. difficile. B. bifidum reduced biofilm at 1.25 mg/ml by 49% and L. plantarum by 31%. MTT assay showed both postbiotics had little influence on cell viability, which was over 80%. The detoxification power of postbiotics revealed that B. bifidum decreased toxin A and B production more effectively than L. plantarum, and also their related tcdA and tcdB genes expression reduction were statistically significant (p < 0.05). Postbiotics' ability to inhibit bacterial growth, biofilm disruption, and toxin reduction makes them a promising adjunctive for CDI treatment and a good solution to pathogens' antibiotic resistance.

Energy-Saving Ambient Electrosynthesis of Nylon-6 Precursor Coupled with Electrocatalytic Upcycling of Polyethylene Terephthalate.

Cyclohexanone oxime is an important intermediate in the chemical industry, especially for the manufacture of nylon-6. The traditional cyclohexanone oxime production strongly relies on cyclohexanone-hydroxylamine and cyclohexanone ammoxidation processes, which require harsh reaction conditions and consume considerable amounts of energy. Herein, direct electrosynthesis of cyclohexanone oxime is reported from environmental pollutants nitrite and cyclohexanone with almost 100% yield by using low-cost Cu2Se nanosheets as electrocatalysts. Combination of in situ Fourier transform infrared spectroscopy and theoretical calculations verifies that the p-d orbital hybridization between Cu and Se elements could synergistically optimize the surface electronic structure and enable improved adsorption and formation of the key active N intermediate NH2OH*, thereby enhancing cyclohexanone/nitrite-to-cyclohexanone oxime conversion over the Cu2Se nanosheets. Based on these, an efficient asymmetric co-electrolysis system is further demonstrated by coupling cyclohexanone/nitrite-to-cyclohexanone oxime conversion with the upcycling of polyethylene terephthalate plastics, achieveing energy-saving simultaneously production of value-added products (cyclohexanone oxime and glycolic acid).

Evaluating Osteogenic Cell Differentiation Efficacy in the Presence of Polylactide Samples With Varied Compositions for Bone Grafting: In Vitro Study.

In oral implantology, surgeons often confront the need to improve alveolar bone quality and volume before implantation in patients with bone defects. Whereas guided bone regeneration with titanium meshes is a clinical gold standard for bone augmentation, mesh removal pre-implantation presents a drawback. This study explores biodegradable scaffolds as an alternative. The research investigates the impact of various compositions of customized bone-grafting scaffolds on proliferation and osteogenic differentiation processes in vitro. Plates (10 × 10 × 0.5 mm) were fabricated from polylactide (PLA), PLA with 15% hydroxyapatite nanoparticles (PLA/HA), and polylactide with glycolic acid copolymers (PLGA 60:40 and 85:15). Gingival fibroblasts assessed the influence of experimental samples on proliferation and osteogenic differentiation in a low-glucose medium. Osteogenic differentiation was induced, and alizarin red staining measured extracellular matrix calcification via spectrophotometry. Active proliferation of gingival fibroblasts occurred along scaffold edges during cultivation. Although cells proliferated with experimental samples, rates were lower than control cells. PLA/HA showed higher alizarin red staining intensity, indicating enhanced matrix calcification. Experimental samples (PLA, PLA/HA, PLGA 85:15, PLGA 60:40) supported cell proliferation at lower rates than control. PLA/HA demonstrated increased matrix calcification. Biodegradable membranes were nontoxic, suggesting potential for bone augmentation.

Synergistic interaction of biochar, Phragmites australis, and rhizosphere microorganisms for enhanced 1,4-dioxane biodegradation

The application of constructed wetlands (CW) system for removing of emerging contaminants from wastewater industry has been recently investigated. However, there is still a research gap in ensuring adequate synergism between aquatic plants and rhizosphere microorganisms for removal of 1,4-dioxane. This research gap was comprehensively addressed here by implementing biochar-amended constructed wetlands (BCWs) for treatment of 1,4-dioxane-laden wastewater, focusing on the biodegradation mechanisms, and associated microbial activity and diversity. Three sequential BCW1, BCW2 and BCW3 units provided an effluent quality of 60.9 ± 20.8 mg/L for chemical oxygen demand (COD), 3.7 ± 0.9 mg/L for 1,4-dioxane, and 5.6 ± 1.9 mg/L for total nitrogen at total hydraulic retention time (HRT) of 1.4 d., and hydraulic loading rate of 178.6 L/m2. d. The main metabolites by-products were ethylene glycol (8.3–13.8 mg/L), glycolaldehyde (6.6–8.3 mg/L), glycolic acid (4.5–8.9 mg/L), and oxalic acid (3.0–6.3 mg/L). Acidobacteriota (3.7 %), Bacteroidota (26.0 %), Chloroflexi (4.6 %), and Proteobacteria (25.5 %) were abundant at the phylum level, whereas Afipia (1.4 %) and Mycobacterium (6.5 %), i.e., dioxane degraders, were dominant at the genus level. The main 1,4-dioxane removal mechanisms were uptake/volatilization by Phragmites australis (40.9 ± 3.8 %) and biodegradation by biofilm-attached biochar (33.04 ± 2.2 %) followed photo-oxidation (16 ± 1.8 %). Hence, biochar/wetlands cultivated by Phragmites australis could be efficiently employed for treatment of dioxane-laden industrial effluents.

High‐Efficiency Dimethyl Adipate Hydrogenation for 1,6‐Hexanediol Synthesis Over the Cu/SiO2 Nanoparticles with Reasonably Modulations of Pore Structure and Dispersion via Surface‐Assisted Method

AbstractSurfactant‐assisted co‐precipitation for catalyst preparation is an excellent potential preparation method for enhanced metal‐support interactions and abundant oxygen vacancy. Cu/SiO2 catalysts were prepared containing either glycolic acid ethoxylate lauryl ether (BRIJ35, B5), polyethylene oxide‐polypropylene oxide‐polyethylene oxide (P123 P3), or no surfactant. After further treatment with surfactants, the 1,6‐hexanediol selectivity was significantly increased, especially for P123 surfactant. The Cu/SiO2‐P3 catalyst showed good performance, which may be related to more surface basic amount, the larger dispersion of the Cu and abundant oxygen vacancy. Abundant Ovac may facilitate the hydrogenation of DMA by weakening the C=O bond. After the Cu/SiO2 catalyst was treated with surfactant, the micropores disappeared and SBET of the catalyst increased. Among them, Cu/SiO2‐P3 had the largest specific surface area (312.6 m2 g−1).

Overexpression of the β-Subunit of Acid Ceramidase in the Epidermis of Mice Provokes Atopic Dermatitis-like Skin Symptoms.

We previously reported that a pathogenic abnormality in the barrier and water-holding functions of the stratum corneum (SC) in the skin of patients with atopic dermatitis (AD) is mainly attributable to significantly decreased levels of total ceramides in the SC. That decrease is mediated by the abnormal expression of a novel ceramide-reducing enzyme, sphingomyelin/glucosylceramide deacylase (SGDase), which is the β-subunit (ASAH1b) of acid ceramidase. In this study, we determined whether mice overexpressing ASAH1b in their epidermis develop AD-like skin symptoms. We generated transgenic (TG) mice overexpressing ASAH1b, regulated by the involucrin promoter, to localize its expression in the upper epidermis. After hair removal using a depilatory cream containing glycolic acid, the TG mice without any visible skin inflammation at 8 weeks of age had increased levels of ASAH1b and decreased levels of SC ceramide, with disrupted barrier functions measured by trans-epidermal water loss compared to the wild-type (WT) mice. Interestingly, enzymatic assays revealed that SGDase activity was not detectable in the skin of the TG mice compared to WT mice. Immunological staining revealed that there was an increased expression level of IL-33 in the epidermis and an accumulation of macrophages in the dermis of TG mice compared to WT mice, which are phenotypic characteristics of AD, that were exacerbated by tape-stripping of the skin. In the skin of the TG mice, the mRNA levels of IL-5, CCL11, IL-22, CXCL10, and IFNγ were significantly upregulated compared to the WT mice, and tape-stripping significantly increased the mRNA levels of IL-4, IL-33, CXCL1, CXCL12, TLR9, and CD163 compared to WT mice. These findings strongly indicate that the skin of the depilatory cream-treated TG mice exists in an atopic dry skin condition that is highly sensitive to various environmental stimuli. The sum of our results suggests that ASAH1b itself, even in the absence of its enzymatic activity, is a major etiologic factor for atopic dry skin symptoms via an unknown mechanism.

Photoelectrochemical Oxidation of Glycerol over g-C3N4 Nanosheets Coupled with Metal-Assisted Hybrid Carbon Quantum Dots

Carbon quantum dots (CDs) are the most promising candidates of the carbon family with a size of less than 10nm. They owned superior properties such as high solubility in aqueous medium, low toxicity, biocompatibility, stable photoluminescence, spectral convertor, and act as electron reservoirs. These properties make CDs suitable for photo-electrochemical catalytic applications. Low quantum yield and activity in the visible light spectrum of CDs may restrict their applicability. To address this issue, doping and surface passivation of CDs is the only approach to improve their physicochemical characteristics, visible light absorption, and quantum yield by altering their size and structure. Metals are electron-efficient entities and act as electron donors. As a result, when metal ions are doped into CDs, the charge density and charge transition between the core of the CDs and the metal ions increases. This results in a greater improvement in the physicochemical properties of CDs as compared to non-metal doping[1]. Metal-assisted CDs i.e. hybrid CDs tend to modulate energy band positions, change the electronic structure, increase quantum yield, and generate new emissive traps in CDs. The photoluminescence property of CDs can be enhanced due to the surface plasmonic resonance (SPR) effects of metal nanoparticles (NPs). Hybrid CDs also show better catalytic performance as compared to the pristine CDs. It helps to enhance the active sites on the CDs surface to facilitate catalytic performance.By keeping these properties, the hybrid CDs were effectively utilized in the field of dye decolorization, degradation of water pollutants, storage materials, and as a sensor[2][3]. The photo-assisted electrochemical glycerol valorization is one of the prominent methods for producing value-added chemicals such as glycolic acid. However, it is a challenge to achieve high yield and selectivity of products. This research investigated the fabrication of heterojunction of g-C3N4 (CN) with CDs and Bi-assisted CDs (BiCD) as a sustainable photoactive material. The heterojunction was obtained by incorporating CDs and BiCD (5wt.% each) onto CN nanosheets by in-situ thermal polymerization treatment and named CDCN and BiCDCN. The prepared composite was analyzed by structural (XRD), functional (XPS) microscopic (FESEM, FETEM) spectroscopic (UV-Vis, PL, TRPL, EDS), and photoelectrochemical characterization techniques.The band gap of CN was obtained as 2.78 eV which was reduced to 2.69 eV for CDCN and 2.62eV for BiCDCN, increasing the absorbance in the visible light zone. The existence of CDs and BiCDs was confirmed by, FETEM investigation (Fig.1a). The XPS analysis of the composite revealed the presence of Bi 4f chemical state of bismuth metal. The calculated TRPL lifetime was 0.28ns for BiCDCN and 2.51 ns for CDCN which was lower than that of CN (9.31 ns) suggesting the rapid electron transfer ability of BiCDCN. In the presence of light and glycerol, the composite BiCDCN had the maximum photocurrent density of 12 mA/cm2, followed by CDCN (1.6 mA/cm2) and CN (1.3 mA/cm2) at 1.2 V. The photoelectrochemical oxidation of glycerol was performed at 0.8V for 3h. The detected products were glycolic acid, glyceric, glyoxylic acid, and oxalic acid. The addition of CD to CN increased the glycerol conversion and yield of glycolic acid & glyoxylic acid significantly. The composite exhibited 43% selectivity towards glycolic acid and 34% for glyoxylic acid. The glycerol conversion and yield of these two products were further enhanced by Bi doping. BiCDCN had a total glycerol conversion of 21%, followed by CDCN at 5.7% and CN at 3.8%. The BiCDCN had the highest yield of glycolic acid at 8.9 % and that for CDCN was 2.4 % and 1.2 % for CN (Fig.1b). The glyoxylic acid yield was 7.2%, 2.2%, and 0.8% for BiCDCN, CDCN, and CN, respectively. Figure 1

Electrochemical Conversion of Low-Cost Glycerol to Valuable Products

Over the last years, biodiesel production, a renewable fuel derived from biomass, has significantly increased, reaching an output of 40 million tons annually. This surge in production has resulted in excessive glycerol production, as a byproduct, accounting for 10 wt.% of biodiesel production. By 2025, it is predicted that glycerol production will amount to 6.3 million tons.1 However, the low demand for glycerol not only causes high disposal costs for this waste byproduct but also poses a threat to the ecosystem. Consequently, the valorization of glycerol is crucial for enhancing the biodiesel industry's economic viability and environmental sustainability.Among all the techniques for the valorization of glycerol, such as catalytic oxidation, dehydration, and hydrogenolysis, the electrochemical oxidation of glycerol stands out for its cost-effectiveness, simplicity, and eco-friendliness. The glycerol electrooxidation reaction (GOR) can yield a wide range of valuable chemicals, such as C3 products (glyceraldehyde, lactic acid, glyceric acid, tartronic acid), C2 products (glycolic acid, oxalic acid, acetic acid), and C1 products (formic acid). Among all the products, C3 products have notably higher economic value compared to others. In particular, glyceric acid stood out by having a price of over 200 folds of glycerol and having the highest worldwide demand among all the GOR products.2 However, a significant technical challenge lies in developing a highly selective catalyst for C3 products showing high activity, and stability. Thus far, most of the catalyst developed for GOR includes noble metals or their alloys, which limits their usage in realistic systems due to their high cost and scarcity.3 Therefore, developing a cost-effective catalyst with high selectivity, activity, and stability is necessary to make the valorization of glycerol economically viable.In this work, we demonstrate a bimetallic catalyst that, despite its low noble metal content, achieves high selectivity towards glyceric acid, along with notable catalytic activity and stability. Our analysis focuses on the impact of noble metal amount on activity and stability, and parametric analysis to improve the selectivity of C3 products. Furthermore, we outline the reasons for the discrepancies in the quantification of GOR products, especially in applying H-NMR analysis, and discuss the methods to improve the precision in GOR product analysis.

Exploring yeast biodiversity and process conditions for optimizing ethylene glycol conversion into glycolic acid.

Plastics have become an indispensable material in many fields of human activities, with production increasing every year; however, most of the plastic waste is still incinerated or landfilled, and only 10% of the new plastic is recycled even once. Among all plastics, polyethylene terephthalate (PET) is the most produced polyester worldwide; ethylene glycol (EG) is one of the two monomers released by the biorecycling of PET. While most research focuses on bacterial EG metabolism, this work reports the ability of Saccharomyces cerevisiae and nine other common laboratory yeast species not only to consume EG, but also to produce glycolic acid (GA) as the main by-product. A two-step bioconversion of EG to GA by S. cerevisiae was optimized by a design of experiment approach, obtaining 4.51±0.12g l-1 of GA with a conversion of 94.25±1.74% from 6.21±0.04g l-1 EG. To improve the titer, screening of yeast biodiversity identified Scheffersomyces stipitis as the best GA producer, obtaining 23.79±1.19g l-1 of GA (yield 76.68%) in bioreactor fermentation, with a single-step bioprocess. Our findings contribute in laying the ground for EG upcycling strategies with yeasts.

Surface Microfabrication of Lactic Acid–Glycolic Acid Copolymers Using a Gas-Permeable Porous Mold

We attempted to perform surface microfabrication of the bioabsorbable material lactic acid–glycolic acid copolymer (LG-80) using a micro-imprint lithography technique with a gas-permeable porous mold at less than 5 °C. As a result, high-resolution surface micromachining with a height of 1.26 μm and a pitch of 2.97 μm was achieved using a convex sapphire mold with a height of 1.3 μm and a pitch of 3 μm. After processing, the LG-80 exhibited high water repellency, and FT-IR analysis of the surface showed no significant change in its chemical structure, confirming that the surface microfabrication was successful, while retaining the properties of the material. This demonstrated new possibilities for surface microfabrication technology for bioabsorbable materials, which are expected to be applied in the medical and life science fields in products such as surgical implants, tissue regeneration materials, and cell culture scaffold materials. In particular, the use of micro-imprint lithography enables low-cost and high-precision processing, which will be a major step toward the practical application of bioabsorbable materials.

Effects of low-molecular-weight organic acids on the transport of polystyrene nanoplastics: An insight at the structure of organic acids

Plastic nanoparticles are extensively used in various products, leading to inevitable pollution in soil. Understanding their transport in soils where various organic substances exist is crucial. This study examined the impact of low-molecular-weight organic acids (LMWOAs) on the transport of polystyrene nanoplastics (PS-NPs) through saturated quartz sand. The experiments involved three dibasic acids—malonic acid (MA1), malic acid (MA2) and tartaric acid (TA) — and four monobasic acids— formic acid (FA), acetic acid (AA), propanoic acid (PA) and glycolic acid (GA) —under different pH levels (4.0, 5.5, 7.0) and in the presence of cations (Na+, Ca2+). The results demonstrated that in the presence of Na+, dibasic acids significantly enhanced PS-NPs transport, with TA being the most effective, followed by MA2 and MA1. This enhancement is attributed to the adsorption of LMWOAs onto the nanoparticles and sand, creating a more negative ζ-potential, which increases the electrostatic repulsion and decreases the PS-NPs deposition, thereby facilitating the transport. Applying the Derjaguin-Landau-Verwey-Overbeek theory, higher pH levels increased the energy barrier and secondary energy minimum, decreasing PS-NPs deposition. Moreover, dibasic acids significantly enhanced the hydrophilicity of PS-NPs. Conversely, monobasic acids, except for GA, slightly reduced the hydrophilicity of PS-NPs, as indicated by a small increase in the water contact angle, hereby minimally affecting PS-NPs transport. As for GA, although it is a monobasic acid, the additional -OH group in its molecular structure promoted PS-NPs transport, similar to dibasic acids. For example, GA also significantly enhanced the hydrophilicity of PS-NPs. In the presence of Ca2+, the enhancement of PS-NPs transport by LMWOAs was comparable to that with Na+, primarily due to the complex-forming and bridging effects of Ca2+ with the organic acids and PS-NPs. These findings provide important insights into predicting and analyzing the transport behaviors of PS-NPs.

Carrier cascade target delivery of 5-aminolevulinic acid nanoplatform to enhance antitumor efficiency of photodynamic therapy against lung cancer

5-Aminolevulinic acid (5-ALA) is a prodrug of porphyrin IX (PpIX). Disadvantages of 5-ALA include poor stability, rapid elimination, poor bioavailability, and weak cell penetration, which greatly reduce the clinical effect of 5-ALA based photodynamic therapy (PDT). Presently, a novel targeting nanosystem was constructed using gold nanoparticles (AuNPs) as carriers loaded with a CSNIDARAC (CC9)-targeting peptide and 5-ALA via Au-sulphur and ionic bonds, respectively, and then wrapped in polylactic glycolic acid (PLGA) NPs via self-assembly to improve the antitumor effects and reduce the side effect. The successful preparation of ALA/CC9@ AuNPs-PLGA NPs was verified using ultraviolet-visible, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The analyses revealed good sphericity with a particle size of approximately140 nm, Zeta potential of 10.11 mV, and slow-controlled release characteristic in a weak acid environment. Confocal microscopy revealed targeting of NCL-H460 cells by NPs by actively internalising CC9 and avoiding the phagocytic action of RAW264.7 cells, and live fluorescence imaging revealed targeting of tumours in tumour-bearing mice. Compared to free 5-ALA, the nanosystem displayed amplified anticancer activity by increasing production of PpIX and reactive oxygen species to induce mitochondrial pathway apoptosis. Antitumor efficacy was consistently observed in three-dimensionally cultured cells as the loss of integrity of tumour balls. More potent anti-tumour efficacy was demonstrated in xenograft tumour models by decreased growth rate and increased tumour apoptosis. Histological analysis showed that this system was not toxic, with lowered liver toxicity of 5-ALA. Thus, ALA/CC9@AuNPs-PLGA NPs deliver 5-ALA via a carrier cascade, with excellent effects on tumour accumulation and PDT through passive enhanced permeability and retention action and active targeting. This innovative strategy for cancer therapy requires more clinical trials before being implemented.

Influence of diode laser irradiation on microtensile bond strength of etch-and-rinse adhesive to dentin using two different etchants: An in vitro study

Aim: The aim of this study was to evaluate the influence of 970 nm diode laser (DL) irradiation on the microtensile bond strength (µTBS) of etch-and-rinse adhesive (ERA) to dentin using phosphoric acid (PA) or alpha-hydroxy glycolic acid (GA) as etchants. Materials and Methods: A total of 32 human third molars were selected and assigned randomly among two different groups and four subgroups based on etching protocols and DL irradiation: PA, PA-DL, GA, and GA-DL. After tooth preparation and subsequent incremental composite build-up, the samples were stored in distilled water for 24 h at 37°C. µTBS values were obtained using the universal testing machine. The failure modes observed in dentin were categorized as adhesive, cohesive within dentin/resin, or mixed. Statistical Analysis: The data were analyzed using one-way analysis of variance, followed by Tukey’s post hoc test (P ≤ 0.001). Results: GA showed better or similar bond strength values to PA. Furthermore, irradiation of DL increased the µTBS to dentin when both PA or GA are used as etchants. Conclusion: GA can be used as an alternative etchant to PA. DL irradiation stands as a promising approach for elevating the performance of ERA adhesive systems to dentin.