Release Mechanism Research Articles

Polyurea-urethane Temperature-responsive Hydrogels for Sustained Delivery of Anti-VEGF Therapeutics.

Temperature-responsive hydrogels, or thermogels, have emerged as a leading platform for sustained delivery of both small molecule drugs and macromolecular biologic therapeutics. Although thermogel properties can be modulated by varying the polymer's hydrophilic-hydrophobic balance, molecular weight and degree of branching, varying the supramolecular donor-acceptor interactions on the polymer remains surprisingly overlooked. Herein, to study the influence of enhanced hydrogen bonding on thermogelation, we synthesized a family of amphiphilic polymers containing urea and urethane linkages using quinuclidine as an organocatalyst. Our findings showed that the presence of strongly hydrogen bonding urea linkages significantly enhanced polymer hydration in water, in turn affecting hierarchical polymer self-assembly and macroscopic gel properties such as sol-gel phase transition temperature and gel stiffness. Additionally, analysis of the sustained release profiles of Aflibercept, an FDA-approved protein biologic for anti-angiogenic treatment, showed that urea bonds on the thermogel were able to significantly alter the drug release mechanism and kinetics compared to usage of polyurethane gels of similar composition and molecular weight. Our findings demonstrate the unrealized possibility of modulating gel properties and outcomes of sustained drug delivery through judicious variation of hydrogen bonding motifs on the polymer structure.

Microfluidic aerosol-assisted synthesis of gefitinib anticancer drug nanocarrier based on chitosan natural polymer

An aerosol-assisted approach was devised to synthesize gefitinib anticancer drug-loaded chitosan nanocarriers (GefNCs). The nanocarrier synthesis involves mixing and interacting gefitinib molecules with chitosan natural polymer within a microfluidic chip. The combination was nebulized with an on-chip integrated micropneumatic nebulizer with N2 as the nebulizer gas. The aerosol was collected in a beaker containing a glutaraldehyde cross-linking agent while magnetically stirring. The chip was created by CO2 laser engraving on polymethyl methacrylate sheets. The synthesized GefNCs were characterized using FTIR, DLS, FESEM, and TEM. The FESEM images revealed a nanoparticle size distribution of 18.5 ± 4.6 nm. After adjusting numerous experimental parameters such as chip design, polymer concentration, solution flow rate, and nebulizer gas flow rate, the synthesized nanocarrier's release mechanism was investigated using various kinetic models. The results demonstrated that the release behavior of GefNCs is pH-sensitive and greater at acidic pH values than physiological pH, making the synthesized nanocarrier a potential for targeted gefitinib delivery to cancer cells. Furthermore, the kinetic studies revealed that the drug's release mechanism best matches Fick's diffusion rule. Under optimal conditions, the encapsulation efficiency was 77.8 %. The cytotoxicity of the produced nanocarrier was investigated on the A549 non-small cell lung carcinoma. The MTT test revealed that the produced nanocarrier had a lower IC50 than the free medication. Furthermore, cytotoxicity experiments on empty nanocarriers revealed that the materials utilized to synthesize nanocarriers have no appreciable cytotoxicity. The developed microfluidic-assisted approach provides a quicker synthesis procedure with a high encapsulation efficiency.

Insight into the mechanism of adsorption and release of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in sewage by modeling regional suspended particles for evaluation of the influence on monitoring of cannabis illicit abuse

The adsorption of 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THC-COOH) by the suspended particles in sewage makes it fail to accurately monitor cannabis abuse. In this work, the model sewage sample was prepared through equivalent mixing the sewage from 10 different sewage treatment plants in Guangdong province of China and used as a comprehensive representative for investigating the adsorption and release behavior of THC-COOH on the suspended particles under different temperature and pH. The solid-liquid distribution of THC-COOH in sewage depended strongly on the adsorption and release properties which were susceptible to the temperature and pH, specially adjusting pH to 11.0 could release more than 90 % of THC-COOH from the suspended particles. By means of the kinetics models, pseudo-second-order kinetic and Weber-Morris models revealed the mechanism of adsorption and release of THC-COOH in sewage that was a relatively reversible and controllable process with multiple interactions, and then it was further confirmed by the validation experiment in a variety of actual sewage samples. According to the suggested pH, the modification of the existing detection protocol prior to high performance liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-TQ-MS/MS), was successfully applied to determination of THC-COOH in the stimulated positive samples, and the recoveries and RSDs were respectively 95.48–99.79 % and 4.0–5.6 %. The finding could greatly help improving the accuracy of not only the detection of THC-COOH in sewage but also the estimation data of the consumption level of cannabis in the related regions.

Research on the Design of Aviation and Aerospace Hatch Door Mechanisms and Their Future Bionic Prospects

The design of the space hatch door mechanisms is crucial in the aerospace field, impacting not only durability and reliability but also the life safety of astronauts during space missions. This review extensively researches vehicle doors and hatches in civil and military systems across various environments, including land, sea, deep sea, aviation, aerospace, and extreme conditions. Specially, it focuses on the structural design of hatches and related mechanisms in civil aviation and military aerospace environments, such as opening and closing mechanisms, release mechanisms, locking mechanisms, sealing mechanisms, and the ergonomic design of door structures. The review highlights the integration of bionic design principles with hatch mechanisms to explore future solutions. By systematically examining these aeras, this review addresses the lack of comprehensive studies in previous reviews, which often overlook the interconnectivity and applicability of hatch mechanisms across different fields. The absence of such holistic reviews has led to fragmented knowledge and missed opportunities for cross-industry innovation. This review aims to fill these gaps by providing a wide range of design solutions and offering insights that can enhance the development of more reliable, efficient, and safe hatch mechanisms in aerospace and other high-stakes environments.

Histamine in the neocortex: Towards integrating multiscale effectors.

Histamine is a modulatory neurotransmitter, which has received relatively less attention in the central nervous system than other neurotransmitters. The functional role of histamine in the neocortex, the brain region that controls higher-order cognitive functions such as attention, learning and memory, remains largely unknown. This article focuses on the emerging roles and mechanisms of histamine release in the neocortex. We describe gaps in current knowledge and propose the application of interdisciplinary tools to dissect the detailed multiscale functional logic of histaminergic action in the neocortex ranging from sub-cellular, cellular, dendritic and synaptic levels to microcircuits and mesoscale effects.

Some like it hot: Seed thermal threshold variation in obligate seeding Acacia pulchella along a climate gradient

Dormancy in seeds is a key persistence mechanism for many flowering plants. Physically dormant (PY) seeds have water impermeable seed coats, and in fire-prone systems a common mechanism for dormancy release is fire-induced soil heating. However, the thermal thresholds innate to seeds with PY may be influenced by vegetation, climate, and fire regimes, varying substantially between populations of the same species. To investigate intraspecific variation of thermal thresholds in PY seeds, we sampled obligate seeding Acacia pulchella (Fabaceae) which produces PY seeds. Sampling was undertaken from 13 populations across a climate gradient of rainfall and temperature, and between two vegetation communities in fire-prone Mediterranean-type ecosystems of south-west Western Australia. To test a range of weather and fire-induced soil heating dormancy-break scenarios, we conducted dry heat shock experiments between 40 and 140 °C for 10 min and scored germination for 16 weeks. We created population-specific thermal performance curves and extracted the dormancy release temperature at which 50 % of the seeds had germinated (DRT50), the optimum dormancy-breaking temperature to stimulate maximum germination (T0), and the lethal temperature at which 50 % of the seeds were killed (LT50). Generalised linear models were used to examine relationships between thermal thresholds and possible vegetation, climate, and fire regime drivers of intraspecific variation in seed traits. We found that thermal thresholds differed between vegetation communities, with thresholds consistently higher in forest-type ecosystems compared to open woodland, and the influence of climate varied significantly between the two communities. Seeds from Jarrah Forest populations had a DRT50 16.0 °C higher, a T0 9.7 °C higher, and LT50 7.8 °C higher than seeds from Banksia woodlands. A high rate of non-dormancy was identified in one population that had lost fire in its system and displayed significant germination after both summer and fire-related temperatures. The PY thermal thresholds modelled here provide insight into the strong influence of variable soil heating as a function of vegetation and fuel dynamics in fire-prone environments. Our findings highlight the significant intraspecific variation for this species and suggest that fire-induced soil heating generated by vegetation characteristics may be an overlooked element of fire regimes shaping seed traits.

Elucidating and Optimizing the Photochemical Mechanism of Coumarin-Caged Tertiary Amines.

Photoactivatable or "caged" pharmacological agents combine the high spatiotemporal specificity of light application with the molecular specificity of drugs. A key factor in all optopharmacology experiments is the mechanism of uncaging, which dictates the photochemical quantum yield and determines the byproducts produced by the light-driven chemical reaction. In previous work, we demonstrated that coumarin-based photolabile groups could be used to cage tertiary amine drugs as quaternary ammonium salts. Although stable, water-soluble, and useful for experiments in brain tissue, these first-generation compounds exhibit relatively low uncaging quantum yield (Φu < 1%) and release the toxic byproduct formaldehyde upon photolysis. Here, we elucidate the photochemical mechanisms of coumarin-caged tertiary amines and then optimize the major pathway using chemical modification. We discovered that the combination of 3,3-dicarboxyazetidine and bromine substituents shift the mechanism of release to heterolysis, eliminating the formaldehyde byproduct and giving photolabile tertiary amine drugs with Φu > 20%─a 35-fold increase in uncaging efficiency. This new "ABC" cage allows synthesis of improved photoactivatable derivatives of escitalopram and nicotine along with a novel caged agonist of the oxytocin receptor.

Studies on Sorption and Release of Doxycycline Hydrochloride from Zwitterionic Microparticles with Carboxybetaine Moieties.

The aim of this study was to examine the use of zwitterionic microparticles as new and efficient macromolecular supports for the sorption of an antibiotic (doxycycline hydrochloride, DCH) from aqueous solution. The effect of relevant process parameters of sorption, like dosage of microparticles, pH value, contact time, the initial concentration of drug and temperature, was evaluated to obtain the optimal experimental conditions. The sorption kinetics were investigated using Lagergren, Ho, Elovich and Weber-Morris models, respectively. The sorption efficiency was characterized by applying the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The calculated thermodynamic parameters (ΔH, ΔS and ΔG) show that the sorption of doxycycline hydrochloride onto zwitterionic microparticles is endothermic, spontaneous and favorable at higher temperatures. The maximum identified sorption capacity value is 157.860 mg/g at 308 K. The Higuchi, Korsmeyer-Peppas, Baker-Lonsdale and Kopcha models are used to describe the release studies. In vitro release studies show that the release mechanism of doxycycline hydrochloride from zwitterionic microparticles is predominantly anomalous or non-Fickian diffusion. This study could provide the opportunity to expand the use of these new zwitterionic structures in medicine and water purification.

Mechanical release of homogenous proteins from supramolecular gels

A long-standing challenge is how to formulate proteins and vaccines to retain function during storage and transport and to remove the burdens of cold-chain management. Any solution must be practical to use, with the protein being released or applied using clinically relevant triggers. Advanced biologic therapies are distributed cold, using substantial energy, limiting equitable distribution in low-resource countries and placing responsibility on the user for correct storage and handling. Cold-chain management is the best solution at present for protein transport but requires substantial infrastructure and energy. For example, in research laboratories, a single freezer at −80 °C consumes as much energy per day as a small household1. Of biological (protein or cell) therapies and all vaccines, 75% require cold-chain management; the cost of cold-chain management in clinical trials has increased by about 20% since 2015, reflecting this complexity. Bespoke formulations and excipients are now required, with trehalose2, sucrose or polymers3 widely used, which stabilize proteins by replacing surface water molecules and thereby make denaturation thermodynamically less likely; this has enabled both freeze-dried proteins and frozen proteins. For example, the human papilloma virus vaccine requires aluminium salt adjuvants to function, but these render it unstable against freeze–thaw4, leading to a very complex and expensive supply chain. Other ideas involve ensilication5 and chemical modification of proteins6. In short, protein stabilization is a challenge with no universal solution7,8. Here we designed a stiff hydrogel that stabilizes proteins against thermal denaturation even at 50 °C, and that can, unlike present technologies, deliver pure, excipient-free protein by mechanically releasing it from a syringe. Macromolecules can be loaded at up to 10 wt% without affecting the mechanism of release. This unique stabilization and excipient-free release synergy offers a practical, scalable and versatile solution to enable the low-cost, cold-chain-free and equitable delivery of therapies worldwide.

Gamma-Irradiated Gum Arabic Grafted with 2-Hydroxyethyl Methacrylate: A Novel Superabsorbent Polymer for Controlled Folic Acid Release.

This study explores the synthesis and characterization of superabsorbent hydrogels derived from chemically modified gum Arabic, designed for controlled folic acid release. The synthesis involves a two-step process: carboxymethylation followed by grafting with 2-hydroxyethyl methacrylate via gamma irradiation. The resulting hydrogels exhibit enhanced mechanical strength and controlled diffusivity, essential for nutrient delivery systems. Key factors such as copolymer composition and irradiation dose are investigated, affecting the synthesis process. Systematic studies of swelling behaviors reveal that the hydrogel achieves a maximum swelling of 888.1% at 40°C. The hydrogels are loaded with folic acid, and in vitro, sustained release profiles are examined under various pH conditions. The maximum release of 83.3% is observed after 24h at pH 7.0, following a Korsmeyer-Peppas release mechanism. Different characterization techniques, confirm the successful synthesis and unique properties of the superabsorbent hydrogels. Rheological behavior analysis, scanning electron microscopy, and biocompatibility assessments provide a comprehensive understanding of the hydrogel structures. Gamma irradiation ensures a homogeneous network structure, crucial for optimal swelling behavior and mechanical properties. This research highlights the potential of eco-friendly biopolymer hydrogels in precise drug delivery applications, leveraging the safety and process control benefits of gamma irradiation.

A magnetic-guided nano-antibacterial platform for alternating magnetic field controlled vancomycin release in staphylococcus aureus biofilm eradication.

Bacterial resilience within biofilms, rendering them up to 1000 times more resistant to antibiotic drugs, poses a formidable challenge. This study introduces a targeted biofilm eradication strategy, termed "target-penetration-killing-eradication", implemented through magnetic micro-robotic technology. Specifically, we present the development of a magnetic-guided nano-antibacterial platform designed for alternating magnetic field (AMF) controlled vancomycin release in the eradication of Staphylococcus aureus biofilms. To address the issue of premature vancomycin release in physiological conditions, we employed a temperature-sensitive linking agent, 4,4'-azobis(4-cyano valeric acid), facilitating the conjugation of vancomycin onto Fe3O4/CS nanocomposites, resulting in the novel construct Fe3O4@CS-ACVA-VH. The release mechanism adheres to first-order kinetics and Fickian diffusion, with each 10-min AMF treatment releasing approximately 8.4 ± 1.1% of vancomycin. The potency of vancomycin in the release solution was similar to that of the original drug (MIC: 7.4 ± 3.5 vs. 5.6μg/mL). Fe3O4@CS-ACVA-VH exhibited sustained antibacterial efficacy, inhibiting bacterial growth for four consecutive days and preventing the formation of bacterial biofilms on its surface. Contact-inhibition bacterial activity of Fe3O4@CS-ACVA-VH against S. aureus was 0.046875mg/mL. Conceptually validating our approach, we emphasize Fe3O4@CS-ACVA-VH's exceptional ability to penetrate S. aureus biofilms under static magnetic field attraction. Furthermore, the nano-platform offers the unique advantage of on-demand vancomycin release through alternating magnetic field stimulation, effectively clearing a larger biofilm area. This multifunctional nano-platform demonstrates magnetic-guided biofilm penetration followed by controlled vancomycin release, presenting a promising strategy for enhanced biofilm eradication.

High-Efficiency Degradation of PET Plastics by Glutathione S-Transferase under Mild Conditions.

Plastic pollution is a significant environmental concern globally. Plastics are normally considered chemically inert and resistant to biodegradation. Although many papers have reported enzyme-induced biodegradation of plastics, these studies are primarily limited to enzymes of microbial origin or engineered enzymes. This study reveals that poly(ethylene terephthalate) (PET, ∼6000 Da and 100 kDa) particles and plastic bottle debris (PBD, 24.9 kDa) can be efficiently degraded by a mammal-origin natural phase II metabolic isozyme, glutathione S-transferase (GST), under mild conditions. The degradation efficiency of PET plastics reached 98.9%, with a degradation rate of 2.6 g·L-1·h-1 under ambient or physiological conditions at 1 atm. PET plastics can be degraded by GST with varying environmental or biological factors (i.e., temperature, light irradiation, pH, and presence of humic acid or protein). We suggest a novel mechanism for PET degradation other than hydrolysis, i.e., the mechanism of cleavage and release of PET plastic monomers via nitridation and oxidation. This finding also reveals a novel function of GST, previously thought to only degrade small molecules (<1000 Da). This method has been successfully applied in real human serum samples. Additionally, we have tested and confirmed the ability to degrade PET of a mammal-origin natural digestive enzyme (trypsin) and a human-derived natural metabolic enzyme (CYP450). Overall, our findings provide a potential new route to plastic pollution control and contribute to our understanding of the metabolism and fate of plastics in organisms.

Positive feedback in Ras activation by full-length SOS arises from autoinhibition release mechanism

Signaling through the Ras-MAPK pathway can exhibit switch-like activation, which has been attributed to the underlying positive feedback and bimodality in the activation of RasGDP to RasGTP by SOS. SOS contains both catalytic and allosteric Ras binding sites, and a common assumption is that allosteric activation selectively by RasGTP provides the mechanism of positive feedback. However, recent single-molecule studies have revealed that SOS catalytic rates are independent of the nucleotide state of Ras in the allosteric binding site, raising doubt about this as a positive feedback mechanism. Here, we perform detailed kinetic analyses of receptor-mediated recruitment of full-length SOS to the membrane while simultaneously monitoring its catalytic activation of Ras. These results, along with kinetic modeling, expose the autoinhibition release step in SOS, rather than either recruitment or allosteric activation, as the underlying mechanism giving rise to positive feedback in Ras activation.

Ultrasonic Preparation of Nano-CaCO3 Templates and Hollow Mesoporous SiO2 Nanoparticles for Voriconazole Loading

CaCO3 nanoparticles (nano-CaCO3) as nano-templates were prepared using CaCl2 and Na2CO3 solutions under controlled sonication (19.5 kHz). Using the same ultrasonic device, subsequently, hollow mesoporous silica nanoparticles (HMSNs) were obtained by the hard template of nano-CaCO3. HMSNs were selected as carriers for the antifungal drug voriconazole (VOR) loading to overcome poor water solubility. Three-dimensional CaCO3 nanosheets HMSNs were obtained under gentle sonication. Three-dimensional CaCO3 nanosheets of 24.5 nm (hydrodynamic diameter) were obtained under 17.6 W for 3 min. HMSNs were synthesized by double-template method with nano-CaCO3 as the hard template. Transmission electron microscopy measurements showed that the prepared HMSNs possess hollow structures with particle size between 110 and 120 nm. Nitrogen physisorption at -196 °C revealed that the HMSNs had high surface area (401.57 m2/g), high pore volume (0.11 cm3/g), and uniform pore size (2.22 nm) that facilitated the effective encapsulation of VOR in the HMSNs. The loading capacity of VOR (wt%) on the HMSNs was 7.96%, and the total VOR release amount of VOR-HMSNs material was 71.40% at 480 min. The kinetic model confirmed that the release mechanism of HMSNs nanoparticles followed Fickian diffusion at pH = 7.4 and 37 °C. Moreover, the cumulative VOR release at 42 °C (86.05%) was higher than that at 37 °C (71.40%). The cumulative release amount of VOR from the VOR-HMSNs material was 92.37% at pH = 5.8 at the same temperature. Both nano-CaCO3 templates and HMSNs were prepared by sonication at 19.5 kHz. The as-prepared HMSNs can effectively encapsulate VOR and released drug by Fickian diffusion.Graphical Nano-CaCO3 Templates and Hollow Mesoporous SiO2 Nanoparticles

Analysis of volatile floral fragrance components of Camellia yuhsienensis Hu by HS‐SPME/GC–MS

AbstractThe flowers of selected Camellia yuhsienensis Hu specimens were studied at different stages of flowering to determine the volatile components of floral fragrance and how their concentrations changed during efflorescence. The mechanism of fragrance formation and release was also studied in order to provide a theoretical basis for the practical use of C. yuhsienensis Hu flowers. Headspace solid‐phase microextraction (HS‐SPME) was used to extract the natural floral volatile oils of C. yuhsienensis Hu at the different stages, and the floral fragrance components were analysed by gas chromatography–mass spectrometry (GC–MS). A total of 31, 59 and 55 compounds were detected at the budding, early‐blooming and full‐blooming stages respectively. These floral fragrance components included terpene alcohols, as well as other aromatic and aliphatic compounds, and the relative concentrations of the various compounds at different stages of flowering, were different, and those of fatty alcohols and terpene alcohols having higher relative contents at all stages. The main component at the budding stage of C. yuhsienensis Hu was ocimene, which has a grassy fragrance, accompanied by the scent of neroli oil, which gives it a refreshing, gentle and sweet, and explains why the floral fragrance of C. yuhsienensis Hu at the budding stage is extremely thin: the main component during the early‐blooming stage was 3‐carene. A higher percentage of 3‐carene increased the sweetness of the scent, manifesting the typical fragrant characteristics of C. yuhsienensis Hu. The main identified compound at the full‐blooming stage was α‐farnesene, which has a delicate fragrance, accompanied by a balsamic aroma, similar to the scent of gardenia, which is consistent with the sensory characteristics of C. yuhsienensis Hu.

Optimization of Diclofenac-Loaded Bicomponent Nanofibers: Effect of Gelatin on In Vitro and In Vivo Response.

The use of electrospun fibers as anti-inflammatory drug carriers is currently one of the most interesting approaches for the design of drug delivery systems. In recent years, biodegradable polymers blended with naturally derived ones have been extensively studied to fabricate bioinspired platforms capable of driving biological responses by releasing selected molecular/pharmaceutical signals. Here, sodium diclofenac (DicNa)-loaded electrospun fibers, consisting of polycaprolactone (PCL) or gelatin-functionalized PCL, were studied to evaluate fibroblasts' in vitro and in vivo response. In vitro studies demonstrated that cell adhesion of L929 cells (≈70%) was not affected by the presence of DicNa after 4 h. Moreover, the initial burst release of the drug from PD and PGD fibers, e.g., 80 and 48%, respectively, after 5 h-combined with its sustained release-did not produce any cytotoxic effect and did not negatively influence the biological activity of the cells. In particular, it was demonstrated that the addition of gelatin concurred to slow down the release mechanism, thus limiting the antiproliferative effect of DicNa, as confirmed by the significant increase in cell viability and collagen deposition after 7 days, with respect to PCL alone. In vivo studies in a rat subcutaneous model also confirmed the ability of DicNa-loaded fibers to moderate the inflammatory/foreign body response independently through the presence of gelatin that played a significant role in supporting the formation of small-caliber vessels after 10 days of implantation. All of these results suggest using bicomponent fibers loaded with DicNa as a valid therapeutic tool capable of supporting the wound healing process and limiting in vivo inflammation and rejection phenomena.

Fluconazole adsorption and release study using KIT-6 for targeted and controlled drug delivery system

ABSTRACT This study presents the development of a mesoporous silica, i.e. KIT-6 synthesised using the hydrothermal technique, followed by the loading of fluconazole as the model drug using the post-impregnation method. The results of drug entrapment studies exposed that 76% of the drug was entrapped in the silica matrix. The drug release rate was investigated in phosphate buffer with pH = 6.8. The fluconazole-loaded KIT-6 prolonged the drug’s release for 12 hours, ensuring Higuchi’s square root kinetics, with diffusion via the matrix as the releasing mechanism, which revealed that the release rate was under control. The MTT assay-based biocompatibility experiments on Vero cells show that the pure and drug-loaded composite systems have minimal cytotoxicity. Hence, drug delivery and adsorption may be facilitated, and repeated administration of drugs is reduced by a controlled drug release rate using the prepared silicious composite.

Environment Assessment of Modified Red Mud Utilized in Roadbed

Utilization of red mud in road projects is an effective way to consume large amounts of red mud on a large scale. In order to meet the requirements for road performance, a modified material, Heinchem, has been developed on the basis of extensive experiments, and the long-term environmental risks of red mud modified by this material have been investigated. By collecting and modifying original red mud samples, a series of continuous leaching tank experiments are carried out based on the exposure scenario analysis. According to the leaching content of pollution in the original and modified red mud, the characteristic pollutants are identified. The release mechanism of these characteristic pollutants in the modified red mud is revealed, and the long-term release amount is predicted. Furthermore, in light of the actual road use scenario of the modified red mud, a risk assessment model is established and used to simulate the release, migration, and transformation of characteristic pollutants during the use of modified red mud as roadbed material. The groundwater environmental risk is then assessed. Finally, an acute toxicity test of earthworms and a seed germination test are conducted to investigate the impact of the modified red mud on the farmlands. The results showed that the proposed red mud modified materials have obvious curing effects on V, As, Se, Mo, and F. When the leaching contents of V, Cr6+, Cr3+, As3+, Se4+, Se6+, Mo, and F in the modified red mud were lower than 0.15 mg/L, 0.1 mg/L, 0.2 mg/L, 0.012 mg/L, 0.012 mg/L, 0.012 mg/L, 0.075 mg/L, and 1.2 mg/L, respectively, the environmental risk of modified red mud during long-term road use is acceptable. This study provides a new way for the resource utilization of red mud.

Long-term escape behavior and release mechanism of organic emissions from asphalt materials

In the context of carbon neutrality and carbon peaking, investigating the long-term escape behavior and release mechanism of organic emissions from asphalt materials can contribute to the development of environmentally sustainable asphalt pavements. In this study, the long-term emission behavior and release mechanism of organic emissions from asphalt materials were unraveled by combining the headspace gas chromatography–mass spectrometry (HS-GC–MS), differential scanning calorimetry (DSC), fluorescence microscopy (FM), and Fourier transform infrared spectroscopy (FTIR) tests. The results demonstrate that the pressure aging vessel (PAV) test and the ultraviolet (UV) aging test can result in a notable reduction in the concentration of organic emissions from asphalt materials, respectively. This indicates that asphalt pavements can potentially release a substantial quantity of organic emissions during their long-term service life. Besides, the aging mechanism of asphalt materials is established to unravel the release mechanism of organic emissions from asphalt materials. Aging increases the probability of organic emissions being released and volatilized from asphalt materials, which leads to the organic emissions from asphalt materials being more likely to be released and volatilized. Consequently, the aging process facilitates a greater release and volatilization of organic emissions from asphalt materials, resulting in a decrease in the detected concentration of these emissions after aging.

Curcumin-shellac nanoparticle-loaded GelMA/SilMA hydrogel for colorectal cancer therapy

In this study, a novel approach was employed to develop a therapeutic system for colorectal cancer treatment. Specifically, a GelMA/SilMA hydrogel loaded with curcumin-shellac nanoparticles (Cur@Lac NPs) was created. A microfluidic swirl mixer was utilized to formulate stable Cur@Lac NPs, ensuring their consistent and effective encapsulation. The pH-specific release of curcumin from the NPs demonstrated their potential for colon cancer treatment. By carefully regulating the ratio of GelMA (gelatin methacrylate) and SilMA (silk fibroin methacrylate), a GelMA/SilMA dual network hydrogel was generated, offering controlled release and degradation capabilities. The incorporation of SilMA notably enhanced the mechanical properties of the dual network matrix, improving compression resistance and mitigating deformation. This mechanical improvement is crucial for maintaining the structural integrity of the hydrogel during in vivo applications. In comparison to the direct incubation of curcumin, the strategy of encapsulating curcumin into NPs and embedding them within the GelMA/SilMA hydrogel resulted in more controlled release mechanisms. This controlled release was achieved through the disintegration of the NPs and the swelling and degradation of the hydrogel matrix. The encapsulating strategy also demonstrated enhanced cellular uptake of curcumin, leveraging the advantages of both NPs and in-situ hydrogel injection. This combination ensures a more efficient and sustained delivery of the therapeutic agent directly to the tumor site. Overall, this approach holds significant promise as a smart drug delivery system, potentially improving the efficacy of colorectal cancer treatments by providing targeted, controlled, and sustained drug release with enhanced mechanical stability and biocompatibility.