Slow Degradation Research Articles

Degradation of Poly(ε-caprolactone) Resorbable Multifilament Yarn under Physiological Conditions.

Poly(ε-caprolactone) (PCL) is a hydrophobic, resorbable aliphatic polymer recognized for its low tenacity and extensive elongation at break, making it a popular choice for fabricating biodegradable tissue engineering scaffolds. PCL's slow degradation rate typically results in a complete resorption period of 2 to 3 years. While numerous studies have examined the degradation of PCL in various forms such as films and webs, no study to date has investigated its physiological degradation in multifilament yarn form. In this study, we subjected PCL multifilament yarn samples to physiological conditions in phosphate-buffered saline (PBS) maintained at a consistent temperature of 37 ± 2 °C and agitated at 45 rpm for a period of 32 weeks. We retrieved samples at five different intervals to analyze the degradation profile of the multifilament yarn. This allowed us to estimate the complete resorption time and rate under these in vitro conditions. Over the 32-week period, the multifilament yarn's mass decreased by 4.8%, its elongation at break declined by 42%, the tenacity dropped by 40%, and the peak load at break fell by 46.5%. Based on these findings, we predict that a scaffold structure incorporating PCL multifilament yarn would undergo complete resorption in approximately 14 months under physiological conditions, such as in PBS solution at a pH of approximately 7 and a temperature of 37 °C.

Marine litter-fauna interactions: a standardised reporting framework and critical review of the current state of research with a focus on submarine canyons

Litter is ubiquitous in the ocean, interacting with fauna and causing impacts that are unquantified at present. Mainly sourced from land, marine litter is very persistent, and undergoes slow degradation upon settling on the ocean floor. Submarine canyons contain more litter than other oceanographic features due to hydrological processes, but study of litter in canyons is made difficult by logistical requirements. Monitoring and quantification of marine litter often do not consider interactions between fauna and litter, meaning impacts are largely unconsidered and unknown. Among publications that have reported litter-fauna (L-F) interactions in canyons, the large majority occur in the Mediterranean Sea, and the most reported interaction is of corals entangled in fishing gear. When it occurs, the reporting of L-F interactions is unstandardised, resulting in a lack of global comparison and trend analysis. A standardised, comprehensive framework for the reporting of L-F interactions has been created and includes 6 major categories: entanglement, ingestion, smothering, habitat provision, adaptive behaviour, and encountering (entanglement and smothering occur on abiotic features as well). Use of the framework will aid in research collaboration and creation of a global dataset of L-F interactions. Impacts resulting from interactions are plentiful, most coming from entanglement and smothering.

Apoptin NLS2 homodimerization strategy for improved antibacterial activity and bio-stability.

The emergence of antibiotic resistance prompts exploration of viable antimicrobial peptides (AMPs) designs. The present study explores the antimicrobial prospects of Apoptin nuclear localization sequence (NLS2)-derived peptide ANLP (PRPRTAKRRIRL). Further, we examined the utility of the NLS dimerization strategy for improvement in antimicrobial activity and sustained bio-stability of AMPs. Initially, the antimicrobial potential of ANLP using antimicrobial peptide databases was analyzed. Then, ANLP along with its two homodimer variants namely ANLP-K1 and ANLP-K2 were synthesized and evaluated for antimicrobial activity against Escherichia coli and Salmonella. Among three AMPs, ANLP-K2 showed efficient antibacterial activity with 12µM minimum inhibitory concentration (MIC). Slow degradation of ANLP-K1 (26.48%) and ANLP-K2 (13.21%) compared with linear ANLP (52.33%) at 480min in serum stability assay indicates improved bio-stability of dimeric peptides. The AMPs presented no cytotoxicity in Vero cells. Dye penetration assays confirmed the membrane interacting nature of AMPs. The zeta potential analysis reveals effective charge neutralization of both lipopolysaccharide (LPS) and bacterial cells by dimeric AMPs. The dimeric AMPs on scanning electron microscopy studies showed multiple pore formations on the bacterial surface. Collectively, proposed Lysine scaffold dimerization of Apoptin NLS2 strategy resulted in enhancing antibacterial activity, bio-stability, and could be effective in neutralizing the off-target effect of LPS. In conclusion, these results suggest that nuclear localization sequence with a modified dimeric approach could represent a rich source of template for designing future antimicrobial peptides.

Adaptive evolution of Sphingopyxis sp. MC4 conferred degradation potential for persistent β- and δ-Hexachlorocyclohexane (HCH) isomers

Hexachlorocyclohexane (HCH), an organochlorine pesticide imposes several harmful impacts on the ecosystem. β- and δ-isomers of HCH are highly toxic, persistent, and recalcitrant to biodegradation, slow and incomplete degradation of β- and δ- isomers have been reported in a few strains. We have isolated a strain designated as Sphingopyxis strain MC4 that can tolerate and degrade high concentrations of α-, β-, γ- and δ-HCH isomers. To date, no other Sphingopyxis strain has been reported to degrade β- and δ-isomers. To understand the underlying genetic makeup contributing to adaptations, the whole genome of strain MC4 was sequenced. Comparative genome analysis showed that strain MC4 harbors the complete pathway (lin genes) required for HCH degradation. Genetic footprints such as presence of lin genes on genomic islands, IS6100 elements in close proximity of lin genes, and synteny in lin flanking regions with other strains reflects the horizontal gene transfer in strain MC4. Positive selection and HGT drive the adaptive evolution of strain MC4 under the pressure of HCH contamination that it experienced in its surrounding niche. In silico analyses showed efficient binding of β- and δ-isomers with enzymes leading to rapid degradation that need further validation by cloning and biochemical experiments.

Comparative Study of Environmental Migration Issues in Bangladesh and Singapore

As the global climate crisis increasingly exacerbates, many countries are faced with more frequent natural disasters and the acceleration of slow on-set environmental degradation. In such context, environmental migration, comes into the international communitys view. Though not a new phenomenon, environmental migration fails to fit in the current migration framework due to its multidisciplinary nature, as a result, therere no explicit legal documents and mechanism to protect environmental migrants. In response to the inaction, this article investigates the key factors of environmental migration and possible pathways through the comparative study of Bangladesh and Singapore. In the first part, the impact of climate change on both states are examined and compared. In the next part, the difficulties in defining and tackling environmental migration issues are proposed, followed by the overview of current legal pathways of Bangladesh, Singapore and international law. In the third part, principles concerning environmental migrants human rights protection are discussed, and viable policy options are based on those principles and previous review of Bangladesh and Singapores situation, reflecting on how the two states could act as examples to inspire the international community.

Developing a Prolamin-Based Gel for Food Packaging: In-Vitro Assessment of Cytocompatibility.

Growing environmental concerns drive efforts to reduce packaging waste by adopting biodegradable polymers, coatings, and films. However, biodegradable materials used in packaging face challenges related to barrier properties, mechanical strength, and processing compatibility. A composite gel was developed using biodegradable compounds (prolamin, d-mannose, citric acid), as a coating to increase the oxygen barrier of food packaging materials. To improve gel stability and mechanical properties, the gels were physically cross-linked with particles synthesized from tetraethyl orthosilicate and tetramethyl orthosilicate precursors. Additionally, biocompatibility assessments were performed on human keratinocytes and fibroblasts, demonstrating the safety of the gels for consumer contact. The gel properties were characterized, including molecular structure, morphology, and topography. Biocompatibility of the gels was assessed using bioluminescent ATP assay to detect cell viability, lactate dehydrogenase assay to determine cell cytotoxicity, and a leukocyte stimulation test to detect inflammatory potential. A composite gel with strong oxygen barrier properties in low-humidity environments was prepared. Increasing the silane precursor to 50 wt% during gel preparation slowed degradation in water. The addition of citric acid decreased gel solubility. However, higher precursor amounts increased surface roughness, making the gel more brittle yet mechanically resistant. The increase of precursor in the gel also increased gel viscosity. Importantly, the gels showed no cytotoxicity on human keratinocytes or fibroblasts and had no inflammatory effects on leukocytes. This composite gel holds promise for oxygen barrier food packaging and is safe for consumer contact. Further research should focus on optimizing the stability of the oxygen barrier in humid environments and investigate the potential sensitizing effects of biodegradable materials on consumers.

Laboratory simulated aging of polystyrene particles and characterization of the resulting nanoscale plastics

Plastics are increasingly produced and used worldwide for their easy accessibility and cost-effectiveness. However, improper plastic disposal has led to ecosystem pollution due to their slow degradation in the natural environment. While worldwide polystyrene (PS) production is estimated at around 21 million tons (8% of all polymer types), the observed PS in recovered plastics from environmental samples does not align with this production volume. Therefore, we hypothesize that the chemical composition of PS might undergo alternations during natural weathering, resulting in fewer identifiable PS components in extracted waste or other environmental samples. To test this hypothesis and comprehend the potential fate and behavior of PS after aging, we conducted lab-accelerated aging processes on pristine PS particles. Through thermal aging and probe sonication, the size distribution of 500 nm polystyrene particles (PS500) was reduced to around 200 nm, as measured by dynamic light scattering (DLS). We further examined the morphology of processed PS500 using atomic force microscopy (AFM), which confirmed changes in shape and size. In total, 97% of PS500 experienced distinct structural changes, whereas 40% of the particles exhibited a ring-opening reaction arising from the conjugated C=C bond breakage, followed by the C-H bond breakage after the laboratory-accelerate aging process; the remaining particles went through chemical changes to different extents. These physical and chemical changes resulting from the simulated aging process contribute to our understanding of the potential destiny of microplastics, underscoring the significance of weathering factors in micro/nanoplastics research.

Magnetic energy drives mass transfer processes to accelerate the degradation of Fe-based implant

The main obstacle of Fe towards the orthopedic application is the slow degradation rate. In this work, a FeGa alloy is developed by mechanical alloying and selective laser melting, and exposed to magnetic field to investigate the influence of magnetic energy on the degradation behavior of the alloy. The magnetic field magnetizes the FeGa alloy and establishes an induced magnetic field, which forms gradient magnetic energy around the corrosion pits during the degradation period. The gradient magnetic energy transfers the paramagnetism corrosion product particles like FexOy and GaOx to the edge of the corrosion pits and avoids the deposition of passive corrosion product layer, thereby maintaining the erosion of immersion solution to achieve a continuous corrosion process. Moreover, the magnetic field subjects Lorentz forces to oxygen and the corrosive ions in the medium, which provides driving forces for transferring them to the alloy surface, thereby accelerating the oxygen absorption degradation reaction. Results indicate that FeGa alloy coupled with magnetic field has a smaller charge transfer resistance of 3297.8 Ω than FeGa alloy (4877.2 Ω) and Fe (5951.1 Ω) in the absence of magnetic field, indicating a lower corrosion resistance of the corrosion product layer. Furthermore, the FeGa alloy in magnetic field exhibits high corrosion current density of 28.12 ± 0.35 μA/cm2 and fast corrosion rate of 0.25 ± 0.02 mm/year, which are significantly higher than FeGa alloy and Fe without magnetic field. The findings of this work suggest that combining component design with external field interactions can effectively regulate the degradation of Fe-based implants.

The long-term performance of a bituminous geomembrane (BGM) under single-sided exposure conditions

A custom-designed apparatus (referred to as the Ageing Column) is used to age a 4.8-mm thick elastomeric bituminous geomembrane (BGM) under single-sided exposure to a synthetic municipal solid waste (MSW) leachate and a synthetic high pH mining solution (pH 11.5) at 55 °C, 70 °C, and 85 °C. This apparatus involves a closer simulation of the BGM's chemical exposure conditions in the field than the double-sided immersion tests in which the BGM is exposed to the solution from both surfaces. The mechanical, rheological, and chemical properties of the BGM are examined to assess the degradation in the BGM components relative to double-sided immersion experiments. While the single-sided ageing of the BGM reduces the degradation rates in the BGM mechanical properties, it does not affect the degradation rate of the bitumen coat relative to the double-sided exposure. Additionally, the exposure of the BGM to the MSW leachate resulted in faster degradation in its mechanical properties but slower degradation in the bitumen coat than that obtained in the exposure to the mining solution. However, predictions of the time to nominal failure of the BGM established using Arrhenius modelling at different temperatures show that the temperature effect is more significant on the BGM durability than the chemistry of the considered solutions.

Multiphysics modeling of subcritical crack growth in glass

Subcritical crack growth starting from flaws on glass surfaces/edges causes slow degradation in glass strength. This phenomenon involves multiple physics and is very challenging to predict. In this work, we introduce a novel multiphysics model for subcritical crack growth in glass. This model considers water-assisted stress relaxation, stress-dependent chemical reaction between water and glass, diffusion of water to the crack tip, and reaction-driven slow crack growth. Stress relaxation is achieved by using a Prony series in the bond-based peridynamic viscoelastic model, and a new bond breakage criterion based on the concentration of reaction product is introduced. A displacement-loaded double beam with a pre-crack is used to obtain the crack velocity vs. stress intensity factor (v-K) curve. With proper simplifications and assumptions, v-K curves obtained from the model successfully reproduced their typical patterns in experiments. This model will help us better understand fundamental mechanisms and make predictions for subcritical crack growth in glass.

Design and construction of artificial microbial consortia to enhance lignocellulosic biomass degradation

Cellulose-rich agricultural residues are promising renewable sources for producing various value-added products such as 2nd generation biofuels. However, the efficiency of the bioconversion process is not always satisfactory due to the slow and incomplete degradation of lignocellulosic biomass. An interesting approach would be using microbial communities with high lignocellulose-degrading ability for environmentally friendly pretreatment. This study focused on characterizing the degradation performance of bacteria, fungal, and yeast strains and designing and constructing different microbial consortia for solid-state treatment of wheat bran and wheat straw. The microbial consortia, namely BFY4 and BFY5, contained different bacteria, fungal, and yeast led to high ratios of sugar accumulation ranging from 3.21 to 3.5 with degradation rates over 33%, owing to more favorable hydrolytic enzyme activities and improved reducing sugar yield during the process. After 72 h, the highest FPase (0.213 IU/gds) and xylanase (7.588 IU/gds) activities were also detected in the wheat straw pretreated by BFY4 and BFY5, respectively, while CMCase activity peaked (0.928 IU/gds) when wheat bran was used as substrate. The amount of released glucose increased during the treatment process when the two substrates were used in the same ratio. Our results indicated that substrate composition also plays an important role in the degradation capacity of mixed cultures. These findings can be instrumental in advancing the primary knowledge required to apply such bioprocesses at the pilot scale.

Electrospun nanofiber composite mat based on ulvan for wound dressing applications

Wound dressings can be used to create a temporary healing environment and expedite the wound healing process. Ulvan (ULV) is a sulfated polysaccharide with potent antiviral and anti-inflammatory activities. Polycaprolactone (PCL) is a hydrophobic biodegradable polyester that exhibits slow degradation, strong mechanical strength, and excellent biocompatibility. Electrospun nanofiber matrices mimic the microstructure of the extracellular matrix, allowing them to promote cell proliferation and differentiation. Therefore, the primary objective of this study was to fabricate a polycaprolactone-ulvan fibrous composite mat (PCL-ULV) using the electrospinning technique and to investigate its physical and chemical properties. To assess the characteristics of PCL-ULV, scanning electron microscopy (SEM) was utilized to examine its morphology and diameter distribution. Fourier transform infrared (FTIR) spectroscopy, calcofluor white staining, and monosaccharide analysis were employed to analyze the components of PCL-ULV. Additionally, the water contact angle was measured to evaluate the hydrophilicity. Furthermore, the proliferation and morphology of and gene expression in NIH3T3 fibroblasts on PCL-ULV were assessed. The results showed that the average PCL-ULV fiber diameter was significantly smaller than that of the PCL fibers. The water contact angle measurements indicated that PCL-ULV exhibited better hydrophilicity than the PCL mat. FTIR, calcofluor white staining, and monosaccharide analyses demonstrated that ULV could be successfully coelectrospun with PCL. NIH3T3 fibroblasts cultured on PCL and PCL-ULV showed different cellular behaviors. On PCL-ULV, cell adhesion, proliferation, and stretching were greater than those on PCL. Moreover, the behavior of NIH3T3 fibroblasts on PCL and PCL-ULV differed, as the cells on PCL-ULV exhibited higher proliferation and more stretching. Furthermore, NIH3T3 fibroblasts cultured on ULV-PCL showed higher α-SMA and MMP-9 gene expression and a lower ratio of TIMP-1/MMP-9 than those cultured on PCL. Notably, scarless wounds display lower TIMP/MMP expression ratios than scarring wounds. Thus, the fibrous composite mat PCL-ULV shows potential as a wound dressing for scarless wound healing.

PDA-BPs integrated mussel-inspired multifunctional hydrogel coating on PPENK implants for anti-tumor therapy, antibacterial infection and bone regeneration.

Currently, many cancer patients with bone defects are still threatened by tumor recurrence, postoperative bacterial infection, and massive bone loss. Many methods have been studied to endow bone implants with biocompatibility, but it is difficult to find an implant material that can simultaneously solve the problems of anticancer, antibacterial and bone promotion. Here, a multifunctional gelatin methacrylate/dopamine methacrylate adhesive hydrogel coating containing 2D black phosphorus (BP) nanoparticle protected by polydopamine (pBP) is prepared by photocrosslinking to modify the surface of poly (aryl ether nitrile ketone) containing phthalazinone (PPENK) implant. The multifunctional hydrogel coating works in conjunction with pBP, which can deliver drug through photothermal mediation and kill bacteria through photodynamic therapy at the initial phase followed by promotion of osteointegration. In this design, photothermal effect of pBP control the release of doxorubicin hydrochloride loaded via electrostatic attraction. Meanwhile, pBP can generate reactive oxygen species (ROS) to eliminate bacterial infection under 808nm laser. In the slow degradation process, pBP not only effectively consumes excess ROS and avoid apoptosis induced by ROS in normal cells, but also degrade into PO43- to promote osteogenesis. In summary, nanocomposite hydrogel coatings provide a promising strategy for treatment of cancer patients with bone defects.

Managing Microplastics in the Kingston, Ontario, Community: A Novel One Health Innovation

The adverse impacts of microplastics on human health, non-human animals, and the environment are long-standing issues that affect communities across Canada and worldwide. The slow degradation of plastics and their bioaccumulation in plants, animals, and ecosystems can lead to poor growth outcomes and physiological side effects. Comprehensive initiatives that address the "Reduce, Reuse, Recycle" principles for plastic are urgently needed. To support Kingston City Council's mission to reduce plastic and waste contamination in waterways, this proposed initiative aims to redirect plastic bags from entering the environment and repurpose them into sleeping bags.

Fabrication, characterization and potential application of biodegradable polydopamine-modified scaffolds based on natural macromolecules

Sodium alginate (SA)-based implantable scaffolds with slow-release drugs have become increasingly important in the fields of biomedical and tissue engineering. However, high-molecular-weight SA is difficult to remove from the body due to the lack of SA-degrading enzymes. The very slow degradation properties of SA-based scaffolds limit their applications. Herein, we designed a series of biodegradable oxidized SA (OSA)-based scaffolds through amide bonds, imine bonds and hydrogen bridges between OSA and silk fibroin (SF). SF/OSA-0.4 with a blend ratio of 4/1 was chosen for further polydopamine (PDA) surface modification studies through the optimization of those parameters such as different OSA oxidation degrees, and blend ratios. PDA modified SF/OSA-0.4 (Dopa/SF/OSA-0.4) showed the excellent stability, better stretchable properties, a uniform interconnective porous structure, high thermal stability, a low hemolysis ratio and cytotoxicity. In vitro degradation experiments showed that the degradation rate of SF/OSA was significantly higher than that of SF/SA, but the degradation slowed again after PDA modification. Interestingly, the degradation of Dopa/SF/OSA-0.4 in vivo was significantly faster than that in vitro. Dopa/SF/OSA-0.4 was also more conducive to new tissue growth and collagen bundle formation. Moreover, Dopa/SF/OSA-0.4 improved the absorbability of RhB (model drug) and reduced the sudden release of RhB during the sustained release.

Optimized bone grafting.

Bone grafting is routinely performed in periodontology and oral surgery to fill bone voids. While autogenous bone is considered the gold standard because of its regenerative properties, allografts and xenografts have more commonly been utilized owing to their availability as well as their differential regenerative/biomechanical properties. In particular, xenografts are sintered at high temperatures, which allows for their slower degradation and resorption rates and/or nonresorbable features. As a result, clinicians have combined xenografts with other classes of bone grafts (most notably allografts and autografts in various ratios) for procedures requiring better long-term stability, such as contour grafting, sinus elevation procedures, and vertical bone augmentations. This review addresses the regenerative properties of each class of bone grafts and then highlights the importance of understanding each of their biomechanical and regenerative properties for clinical applications, including extraction site management, contour augmentation, sinus grafting, and horizontal and vertical augmentation procedures. Thereafter, an introduction toward the novel production of nonresorbable bone allografts (NRBAs) via high-temperature sintering is presented. These NRBAs not only pose the advantage of being more biocompatible than xenografts owing to their origin (human vs. animal bone) but also display nonresorbable properties similar to those of xenografts. Thus, while packaging allografts with xenografts in premixtures specific to various clinical indications has never been permitted owing to cross-species contamination and FDA/CE requirements, the discovery and production of NRBAs allows premixing with standard allografts in various ratios without regulatory restrictions. Therefore, premixtures of allografts with NRBAs can be produced in various ratios for specific indications (e.g., a 1:1 ratio similar to an allograft/xenograft mixture for sinus grafting) without the need for purchasing separate classes of bone grafts. This optimized form of bone grafting could theoretically provide clinicians more precise ratios without the need to purchase separate bone grafts. This review highlights the future potential for simplified and optimized bone grafting in periodontology and implant dentistry.

Fabrication andin vitroevaluation of photo cross-linkable silk fibroin - epsilon-poly-L-lysine hydrogel for wound repair.

An optimal wound-healing hydrogel requires effective antibacterial properties and a favorable cell adhesion and proliferation environment. AlthoughBombyx morisilk fibroin (SF) possesses inherent wound-healing properties, it lacks these essential qualities. This study aimed to fabricate a novel photo-polymerizable hydrogel by utilizing SF's wound-healing efficiency and the epsilon-poly-L-lysine (EPL) antimicrobial activity. The SF was modified with three different concentrations of glycidyl methacrylate (GMA) to obtain SF-GMA(L), SF-GMA(M), and SF-GMA(H). A methacrylated EPL (EPL-GMA) was also produced. Then, SF-GMA was mixed with EPL-GMA to produce photo-crosslinkable SF-GMA-EPL hydrogels. The SF-GMA(L)-EPL, SF-GMA(M)-EPL, and SF-GMA(H)-EPL hydrogels, fabricated with 20% EPL-GMA, demonstrated maximum antimicrobial activity and mammalian cell adhesion ability. The hydroxyl radical (•OH) scavenging efficiency of the hydrogels was tested and shown to be between 69% and 74%. These hydrogels also exhibited 60% efficiency in removing bacterial lipopolysaccharides. The water absorption ability of the hydrogels was consistent with the size of their internal pores. The hydrogels exhibited a slow degradation fashion, and their degradation products appeared cytocompatible. Finally, the elastomeric properties of the hydrogels were determined, and a storage modulus (G') of 300-600 Pa was demonstrated. In conclusion, the hydrogels created in this study possess excellent biological and physical properties to support wound healing.

Role of marine algal blooms in the release of arsenic at the sediment-seawater interface: Evidence from microcosm experiments

Algal blooms can aggravate arsenic (As) release from sediments and thus pose a pollution risk in the marine environment. However, the driving mechanism of algal blooms on sedimentary As cycling remains unclear. This study undertakes the first comprehensive examination of As release mechanisms under algal bloom conditions based on the evidence provided by temporal and depth profile changes of As species in the overlying water column, porewater and sediment, as well as As-related functional genes over the course of a 30-day incubation experiment using algal addition. The higher rate of increase of dissolved total As (dTAs) concentrations in a high biomass algal group (HAG) than an experimental control group (CG) suggested that algal degradation promoted the release of sedimentary As. The solid phase in all experimental groups remained rich in As(V), while in porewater As(III) and As(V) were the dominant As species during the initial rapid and subsequent slow degradation phases of organic matter, respectively, indicating that microbial reduction of As(V) and Fe(III) controlled the release of As during these two periods. A pronounced increase in arrA gene copies, and not a corresponding increase in the Geobacter copies, in HAG relative to CG supported the notion that algal blooms promoted microbial As(V) reduction. Additionally, the lower concentration of dissolved As(III) and cumulative dTAs flux in the sterilized-HAG treatment than in the sterilized-CG one further suggested that geochemically-mediated processes were not the main pathways of As release. Finally, it is estimated that summer algal blooms in the Changjiang Estuary can cause the release of 1440 kg of sedimentary As into the overlying water.

Antagonistic Potential of Endophytic Bacteria from Shallot against Colletotrichum gloeosporioides Causing Anthracnose Disease

Anthracnose, a highly destructive disease in fruit crops, is primarily caused by the widespread fungal pathogen Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. Currently, chemical fungicides are commonly used to effectively prevent anthracnose infection and spread. However, the excessive and prolonged use of these chemicals has led to the development of resistance in pathogenic fungi. Moreover, chemical fungicides contribute to environmental pollution due to their slow degradation and non-specific toxicity to non-target organisms. As a result, researchers have increasingly focused on developing and implementing alternative methods that are less reliant on fungicides and more environmentally friendly. Endophytic bacteria have been acknowledged as potential biocontrol agents for effectively managing plant diseases. They provide safer alternatives for controlling fungal infections, offering a more environmentally friendly approach compared to chemical fungicides. The objective of this study was to examine the inhibitory effects of fourteen isolates derived from shallot plants on C. gloeosporioides through an in vitro dual culture assay. The isolates were purified and identified as various species belonging to the Bacillus genus. The inhibitory activity was assessed by measuring the percentage inhibition of radial growth. The results indicated that B. velezensis exhibited the highest antagonistic activity (P<0.05), reducing radial growth by 90% compared to the non-treated control. This was followed by B. subtilis at 80%, B. cereus at 39%, B. megaterium at 38%, and B. licheniformis with the lowest inhibition rate at 36%. Furthermore, the production of antifungal volatiles significantly contributed to the antagonistic activity (P<0.05), particularly with B. licheniformis volatiles inhibiting the mycelial growth of C. gloeosporioides. The results of this study indicate that Bacillus species exhibit significant antifungal characteristics and have the potential to be used as biocontrol agents for effectively managing Anthracnose in a variety of crops.

Synthesis and Characterization of Photo-Cross-Linkable Silk Fibroin Methacryloyl Hydrogel for Biomedical Applications.

Photo-cross-linkable hydrogels have recently gained increased interest in the field of biomedical applications. In this study, silk fibroin was derivatized with methacrylic anhydride (MA) to obtain silk fibroin methacryloyl (SFMA), forming hydrogel under UV light exposure in 1 min. The SFMA sol-gel transition did not involve significant structural change at the early stage. Then, the formation of the irreversible β-sheet was confirmed after 24 h. The resulting SFMA hydrogel showed a homogeneous porous structure with pore sizes ranging from 400 to 700 μm, depending on the content. In addition, these hydrogels demonstrated a lower swelling capacity, higher rheological properties and compressive modulus, and slow degradation behavior at higher content, likely due to the higher degree of cross-linking. An experiment with cells indicated the good cell compatibility of these hydrogels, as revealed by Cell Counting Kit-8 (CCK-8) assays. As a tissue-engineered material, this photo-cross-linkable SFMA is expected to have a wide range of applications in the biomedical field.