Objective: To explore the crystallization promotion effect of a representative bio-based polymer, poly(lactic acid), on its stereo isomeric polymer material, and to clarify the structure-activity relationship of nucleating agents in this process. Methods: Different molecular weights of poly(D-lactic acid) (PDLA) were prepared, and the effects of the addition amount, crystallization temperature, and mixing method on the crystallization properties, heat resistance, and mechanical properties of the final material were investigated. Finally, the crystallization promotion effect of PDLA and several commonly used commercial nucleating agents on poly lactic acid was compared to explore the mechanism of the experimental results in this process and to verify the feasibility of PDLA as a nucleating agent for poly lactic acid materials. Results: A variety of molecular weight PDLA bio-based polymer materials were successfully prepared, and the relationship between PDLA molecular weight and its crystallization promotion effect was clarified. The influence of PDLA addition on the crystallization properties of poly lactic acid materials was also clarified. It was verified that different mixing methods and crystallization conditions had no effect on the crystallization promotion effect of PDLA, and it was proved that the crystallization nucleation effect of optimized PDLA was superior to that of commercially available nucleating agents. Conclusion: As a stereoisomer of poly lactic acid, PDLA can be used as a nucleating agent in poly lactic acid material systems, with the advantages of high nucleation efficiency, bio-based, good compatibility, low cost, and degradability.
Objective: The aim of this study is to optimize the preparation process, formulation, and evaluation methods for fish vaccine adjuvants derived from chitosan and its derivatives. Methods: Chitosan and its quaternary ammonium salt granule adjuvant were synthesized from chitosan of specific molecular weight and concentration through high-pressure homogenization and spray-drying techniques suitable for large-scale production. These adjuvants were loaded with inactivated Vibrio anguillarum, subsequently homogenized and emulsified with fish oil to produce an oral vaccine, which was incorporated into the feed and administered to turbot. The concentration of Vibrio anguillarum and the duration of immersion were systematically adjusted to establish an optimal immersion challenge model. Additionally, sodium alginate, β-glucan, and chitosan derivatives were combined to form a composite adjuvant. The immunoprotective efficacy of various composite adjuvants was assessed by evaluating the survival rates and the expression levels of immunity-related genes in turbot after exposure using the immersion challenge model. Results: Chitosan and chitosan quaternary ammonium salt, characterized by a molecular weight of 50 kDa and a mass concentration of 10 mg/mL, were utilized to generate homogeneous particles with a particle size of 220 nm, which served as oral vaccine adjuvants. An immersion challenge model was established for turbot where fish were exposed to Vibrio anguillarum at a concentration of 108 CFU/mL for 12 h. In the immersion challenge experiments, the composite adjuvant formulation combining chitosan quaternary ammonium salt particles and sodium alginate significantly increased the expression levels of immune-related cytokines, such as MHC-I, by 2 to 8 times, and improved the survival rate of turbot from 0% to 30%. Conclusion: The preparation process for chitosan and its quaternary ammonium salt particle adjuvants is suitable for scale-up production. Furthermore, the composite adjuvant of chitosan quaternary ammonium salt particles and sodium alginate significantly improved the immunoprotection conferred by the oral vaccine in turbot during Vibrio anguillarum immersion challenge experiments. This research lays the foundation for the development and industrial production of an oral vaccine adjuvant system for fish based on chitosan and its derivatives.
Objective: Based on the unique advantage of the microfluidic method to precisely control the particle size and size distribution of liposomes in liposome preparation, and in order to overcome the shortcomings such as poor water solubility of Celastrol, Cel-LPs were prepared and the therapeutic effect of Cel-LPs on colorectal cancer was investigated with the aim of providing a safe and effective platform. Methods: Cel-LPs were prepared by the microfluidic method and the formulations were optimized by one-way testing; the morphology, particle size, polydispersity index (PDI), Zeta potential, in vitro release and stability of the optimized formulations of Cel-LPs were investigated; the toxicity of Cel and Cel-LPs on human colon cancer cells (HCT116) was determined by the CCK-8 method; coumarin 6 (coumarin 6, Cou6) was used as a fluorescent substance to prepare coumarin 6 liposomes (Cou6-LPs). The uptake behavior of Cou6-LPs by HCT116 cells was investigated by inverted fluorescence microscopy. Results: The optimized formulation was as follows: aqueous phase to oil phase flow rate ratio of 4.5:1; drug to phospholipid ratio of 1:4; cholesterol to phospholipid ratio of 1:5. Cel-LPs prepared according to the optimized prescription had a spherical appearance and uniform distribution, with particle sizes and PDIs of (85.02 ± 0.43) nm and 0.12 ± 0.01, respectively, a Zeta potential of (-11.4 ± 0.25) mV, and an encapsulation rate of (95.42 ± 0.12)%. The prepared liposomes had good stability and showed a good slow release effect in the in vitro release experiments.Cel-LPs showed good cytotoxicity against HCT116 cells, and inhibited their proliferation more than Cel, with a half inhibitory concentration (IC50) of 6.26 μg/mL.The in vitro cellular uptake experiments showed that HCT116 cells had a better uptake effect of Cou6-LPs in the in vitro cellular uptake experiments. Conclusion: A stable, homogeneous, well-dispersed liposome of tretinoin with a high encapsulation rate was successfully prepared by the microfluidic method, confirming its unique characteristics and promising prospects as a liposome preparation method. The study showed that the liposome could be well taken up and slowly released by HCT116 cells, effectively inhibited the proliferation of HCT116 cells, and demonstrated good anti-tumor effect.
Objective: To study the effects of cell membrane biomimetic gold nanoparticles on cell phenotypes such as proliferation, growth and apoptosis as well as cell ultrastructure during the interactions between cell membrane biomimetic gold nanoparticles and membrane-derived cells. We will then evaluate the coexistence status of nanoparticles and cells. Methods: Hepatic stellate cell membrane biomimetic gold nanoparticle (AuNP@HSCM) were prepared using a mixed mechanical extrusion method. High-resolution transmission electron microscope was used to characterize the nano-biomimetic membrane interaction structure of AuNP@HSCM, and to analyze the subcellular ultrastructural changes of LX-2 hepatic stellate cells before and after treatment with AuNP@HSCM. Optical microscopy, flow cytometry and the CCK-8 method were used to determine the growth status, proliferation and apoptosis phenotypic characteristics of LX-2 hepatic stellate cells. Results: The cell membrane and nanoparticle surface of AuNP@HSCM are well coupled. Compared with polyethylene glycol-modified gold nanoparticles (AuNP@PEG), AuNP@HSCM can be transported to the cell nucleus and has a stronger cellular internalization ability. Unlike AuNP@PEG, which caused the degradation of organelle structures in the cytoplasm, AuNP@HSCM induced bleb-like structures near the cell membrane in LX-2 cells. Compared with AuNP@PEG acting on LX-2 cells, AuNP@HSCM has weaker cytotoxicity at low dose concentrations (≤ 1.5 μg/mL) and can significantly reduce the apoptosis level of LX-2 cells. Conclusion: Cell membrane biomimetic gold nanoparticles AuNP@HSCM have a stable nano-biomimetic membrane coupling structure, and can better achieve structural and functional coexistence with the membrane-derived cell LX-2.
Objective: Pullulan is a microbial polysaccharide with excellent biocompatibility. It has found applications in cosmetics as a moisturizer and thickener. Nevertheless, its limited bioactivity hampers its broader application. Methods: In this study, a pullulan-polyphenol conjugate was synthesized by a mild chemical reaction aimed at enhancing its biological activity. Pullulan was activated by oxidation with sodium periodate followed by reduced amination involving an active amino group. The activated pullulan was grafted with polyphenol through a dehydration condensation reaction catalyzed by EDC, resulting in the formation of the polyphenol conjugate. Results: The successful grafting of polyphenols onto pullulan was confirmed by UV spectroscopy, Fourier transform infrared spectroscopy, and 1H NMR. In vitro comparisons with native pullulan or polyphenols revealed that the pullulan-polyphenol conjugate exhibits enhanced thermal stability, antioxidant activity and moisturizing properties. Additionally, it demonstrated a commendable protective and reparative effect on human immortalized keratinocytes against oxidative damage. Conclusion: The pullulan-polyphenol conjugate has comparable antioxidant and moisturizing properties. It can be developed as a cosmetic raw material.
Objective: The use of immobilized enzyme technology overcomes the disadvantages of soluble enzymes in industrial applications, such as difficult recovery, environmental sensitivity and high cost, improving enzyme environmental stability and reusability of enzymes and reducing application costs. Methods: Balsa wood was selected as the raw material for the carriers, and the wood-based carriers were prepared by removing the lignin. The wood-based carriers were modified and immobilized with horseradish peroxidase (HRP) using citric acid modification, glutaraldehyde activation, and a combination of the two treatments, respectively. The functional groups and structures of the original balsa wood, wood, and HRP@wood were investigated using Fourier infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Conclusion: The wood-based carrier with the combination of the two treatments had a higher immobilization of the enzyme up to 43.0 mg/g, and this immobilized enzyme material was named HRP@wood. Three dyes, crystal violet, methylene blue and Congo red, were selected to test the static decolorization performance of HRP@wood, and the optimal decolorization conditions of HRP@wood for a variety of dyes were determined by investigating the effects of dye concentration, H2O2 concentration and reaction time on the decolorization effect of the dyes. Results: The dyes were decolored at up to 76.9%, 78.2%, and 82.4%, respectively in the first half hour when decolorized under ideal circumstances, which included 12 mg/L crystal violet and 2 mmol/L H2O2, 4 mg/L methylene blue and 0.5 mmol/L H2O2, and 100 mg/L Congo red and 2 mmol/L H2O2. The decolorization rate of methylene blue can reach 100% when the decolorization period was increased to 120 mins. A dynamic decolorization reactor was constructed with this HRP@wood, and the results showed that the reactor had excellent recyclability and decolorization effect.
Objective: A surface grafting method was explored for the preparation of macroporous anion-exchange chromatography media. The chromatographic performance of the medium obtained was evaluated in the present study. Methods: A macroporous anionic chromatography medium was prepared by redox-initiated graft polymerization of 3-(methacryloylamino) propyl trimethylammonium chloride using polyacrylate-based macroporous microspheres as the substrate. The optimal preparation process was determined by single-factor experiments, and the effects of the reaction factors on the chromatographic performance of the medium were investigated in detail. The esterase-like activity of proteins was measured before and after adsorption to determine the change in activity due to the interaction of the medium with the protein molecule. The pressure resistance of the medium was tested under different flow conditions. The stability properties of the medium were tested using 1 mol/L NaOH solution. Th non-specific adsorption of proteins on the medium was tested under non-adsorptive conditions. Plate heights for media packed columns were determined at different flow rates to evaluate column efficiency. High-purity protein was purified from egg white using anion-exchange chromatography. Results: The static binding capacity of the protein on the prepared medium could reach up to 138.94 mg/mL under the optimal preparation conditions. Recovery of protein activity from the medium was up to 98%. The dynamic binding capacity of the medium decreased from 99.234 mg/mL to 93.981 mg/mL in the linear velocity range of 143 to 574 cm/h. The column pressure increased linearly in the range of 143 to 3 871 cm/h linear velocity. The surface and internal morphology of the medium was examined using a scanning electron microscope and it was found that grafting polymers had no effect on the pore diameter of the medium. The minimum plate height was 0.059 9 mm at an eluent flow rate of 535 cm/h. The anion-exchange chromatography medium adsorbed 0.136 mg/mL of bovine serum albumin under non-adsorption conditions. The static binding capacity of the protein in the medium decreased by only 2.4% after 96 h of immersion in 1 mol/L NaOH solution. The one-step purification of egg white proteins with the medium resulted in high purity of lysozyme, ovalbumin and ovotransferrin. Conclusion: The media have better mass transfer performance, higher protein activity recovery and lower non-specific adsorption values, with good stability and rigidity compared to conventional media. This type of medium has great potential for high-throughput protein separation.
Objective: By introducing straw fillers from herbaceous plant into polyethylene (PE) resin with high content, large size and fibrous structure, the research on polyethylene based herbal plastic composite was carried out. Methods: Using self-designed equipment to integrate straw and PE particles for feeding, it achieves the temperature up to the melting point of PE through high-speed friction heating before mixing to form a herb-plastic composite. Results: Inside the composite, the size of the straw filler reaches 0.8 ~ 1.0 cm to form a criss-cross structure, thus improving the overall performance. The bending strength and modulus of the composite are 42.8 ~ 76.1 MPa and 3 590 ~ 4 990 MPa, respectively. After soaking for 60 d, the water absorption rates of the composites are all less than 18%. The thermal deformation temperature is 93.5~101.1℃. The nail holding force is up to 3 520 ~ 3 900 N. Conclusion: Through the establishment and development of this technology, it not only lays the foundation for the design and preparation of the bio-based materials from straw with high performances, but also creates a new methodology for high-quality off-field utilization of straw.
Langmuir Blodgett (LB) film technology is a technique that can precisely control the assembly of thin films at the molecular level, and has a wide range of applications in various fields such as biological simulation, sensing technology, materials science and biomedical research. In terms of bio-based materials, LB film technology can produce single or multi-layer ultra-thin bio-based material films, and can effectively control the physical and chemical properties of the films by adjusting the composition of LB films, providing a powerful tool for constructing bio-based materials with specific functions and properties; in terms of bio-based material modification, LB film technology is used to improve the surface properties of materials and to produce coatings with special functions, thereby affecting the biocompatibility and functionality of materials and meeting specific application requirements; in terms of interface interactions between bio-based materials, LB film technology has been used to construct high-performance biosensors for detecting specific biomarkers and monitoring the interactions of biomolecules. As technology advances and the demand for bio-based materials increases, the potential applications of LB film technology in future bio-based material science and technology will continue to expand.
The pharmaceutical industry faces the critical challenge of delivering therapeutic drugs precisely to diseased tissue while minimizing adverse effects on healthy tissue. Achieving this goal requires the development of advanced drug delivery systems capable of efficient drug loading and transport. Diatom frustules, the silica shells of diatoms, have emerged as promising candidates for such systems due to their unique structural and functional properties. These include multi-level micro-nano porosity, a finely detailed natural microstructure, and modifiable surface chemistry. Additionally, diatom frustules offer excellent thermal stability, biocompatibility, accessibility, and environmental friendliness. This article provides a comprehensive review of the structural characteristics, physicochemical properties, and biological safety of diatom frustules in drug delivery applications. It compares these properties with those of other silicon-based nano/micro drug carriers, reviews recent advances in the construction of drug delivery systems utilizing various functionalization strategies applied to diatom frustules, and discusses the current challenges and future directions in the field.
Electrostatically sprayed polylactic acid-glycolic acid(PLGA) copolymer drug-loaded microspheres have promising medical applications due to their controllable particle size and morphology, high drug encapsulation rate, and ability to protect drug activity. The size and shape of microspheres have a significant impact on drug loading and absorption in vivo. By adjusting relevant parameters during electrostatic spraying, drug-loaded microspheres with specific characteristics can be produced.This article provides a comprehensive overview of electrostatic spraying, focusing on how various parameters impact the particle size and morphology of PLGA microspheres. It also delves into the utilization of drug-loaded microspheres in biomedicine and highlights the key challenges in this field. The findings presented heve are intended to serve as a valuable reference for ongoing research.
Chronic wounds in diabetes remain a major clinical and research challenge. Due to the vicious cycle of oxidative stress, bacterial infection, excessive inflammatory response, and impaired angiogenesis, the healing process of diabetic wounds is disrupted, leading to the formation of chronic wounds. Although a variety of clinical methods have been investigated for the treatment of diabetic wounds, the results have not been satisfactory. Metals and their composites are expected to solve these problems. The study found that metal ions are involved in the synthesis and transformation of a variety of enzymes and proteins, thereby affecting a range of cellular activities. However, due to the sudden release and cytotoxicity of metal ions, it is necessary to modify them. At present, silver (Ag), copper (Cu), zinc (Zn), gold (Au) and other metals as nanoparticles and metal-organic skeleton, as well as their composites combined with biological materials (such as chitosan, sodium alginate, and antibiotics) have been widely used and studied in diabetic wounds. In vitro experiments showed that the metals and their composites had good biocompatibility and stability, and inhibited the growth and reproduction of bacterial strains commonly found in diabetic wounds, including gram-positive and gram-negative bacteria. They demonstrated excellent anti-inflammatory, antioxidant, antibacterial and angiogenic properties, and ultimately promoted the healing of diabetic wounds. In summary, metals and their composites not only play a role in various stages of diabetic wound healing, but also provide a stable physiological environment for the process of diabetic wound healing, which is a promising new strategy for the treatment of diabetic wound healing.
