Poly Lactic Acid Research Articles

Demonstrating the key role of Bacillus in poly lactic acid film degradation through statistical analysis and strain screening.

Plastic films are extensively utilized in agriculture, construction, and manufacturing, with their annual production reaching staggering figures. Addressing the global plastic pollution crisis is imperative. One promising approach is the augmentation of plastic films degradation through microbial agents. Consequently, we undertook composting experiments employing various plastics, including Polyethylene (PE), Poly lactic acid (PLA), and a treatment without plastic films addition (CK), mixed with kitchen waste. Employing bipartite association networks and difference significance analysis methods, we scrutinized the impact of different plastics on the microbial community within the compost piles. There were significant disparities in the microbial community composition among three composting piles. To pinpoint the key microorganisms responsible for PLA degradation, we conducted a comparative analysis of microbial species present on PLA compost piles and PLA film surfaces (PLAS), utilizing variance analysis, co-occurrence network analysis, and Spearman's correlation analysis. Our findings identified Bacillus as the pivotal microorganism involved in PLA degradation. Furthermore, employing function prediction by PICRUSt 2, we identified K00016 as the crucial gene facilitating PLA degradation by Bacillus. Subsequently, employing strain screening techniques, we isolated a highly effective PLA-degrading bacterium, Bacillus amyloliquefaciens strain ML274. The PLA films degradation rate of ML274 reached 3.18%. and other strains was lower than 3.0%. Thus, Bacillus emerges as the primary microorganism driving PLA degradation, emphasizing the significance of focusing on Bacillus genus microorganisms in the development of plastic-degrading bacterial agents for future endeavors.

Shock Response of Sandwich Panels with Additively Manufactured Polymer Gyroid Lattice Cores

This work evaluates the shock response of sandwich structures with gyroid lattice cores made from Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), and Thermoplastic Polyurethane (TPU) using shock tube experiments coupled with high-speed photography and digital image correlation (DIC). The study found that gyroid lattice structures exhibit high energy absorption capacity and good structural integrity under shock loading, making them suitable for high strength-to-weight ratio and energy absorption applications in aerospace and defense industries. The sandwich panel with a TPU-core structure exhibited the highest deformation under shock loading, with a maximum deflection of approximately 6mm, followed by ABS at 0.9mm and PLA at 0.82mm. Under shock loading, the sandwich panel with TPU gyroid core exhibited the highest specific deformation energy (0.146J/g), which is consistent with its flexibility, though it remained in the same general order as ABS (0.104J/g) and PLA (0.070J/g). Interestingly, the specific total energy of the TPU gyroid core sandwich, while the lowest at 39.310J/g, was still relatively close to ABS (54.098J/g) and PLA (52.620J/g), despite the substantial difference in inherent stiffness of TPU compared to ABS and PLA. This suggests that while TPU's stiffness is much lower compared to PLA and ABS, its total energy absorption capability in gyroid form is not as drastically reduced, indicating the importance of geometry and mass distribution within the gyroid structure. Overall, the results of this study highlight the importance of careful design and optimization of these structures to utilize their unique properties fully.

Developing novel hybrid bilayer nanofibers based on polylactic acid with impregnation of chamomile essential oil and gallic acid-stabilized silver nanoparticles

This study presents fabrication and characterization of novel chamomile essential oil (CMO)/gallic acid-stabilized silver nanoparticles (gallic acid-nanosilver, GNS), embedded into polylactic acid (PLA)-based hybrid bilayer nanofibers (NFs). Where CMO was impregnated into polyvinyl alcohol (PVA)-polyethylene glycol (PEG) solution and electrospun simultaneously with PLA to obtain PLA/PVA-PEG-CMO NFs (PLA/CMO A2). Meanwhile, GNS were added to PVA-PEG-CMO and electrospun to obtain PLA/PVA-PEG-CMO-GNS NFs (PLA/CMO-GNS A3). Where pure PLA/PVA-PEG NFs were coded pure PLA/A1. Physicochemical properties of fabricated bilayer-NFs were performed using various approaches. Besides, porosity%, swelling, biodegradability, CMO release pattern, antioxidant, antibacterial activity and cytotoxicity were investigated. Study investigation revealed PLA-based bilayer NFs exhibited a biphasic release profile for impregnated CMO. Due to presence of GA, antioxidant property and biocompatibility of PLA/CMO-GNS A3 was superior compared to pure PLA/A1 and PLA/CMO A2. Antibacterial activity was enhanced in presence of CMO in PLA/CMO A2 than pure PLA/A1. Furthermore, addition of GNS in PLA/CMO-GNS A3 displayed highest antibacterial activity due to synergy of CMO/GNS. Finally, MTT assay with HFB4 fibroblasts demonstrated absence of cytotoxicity of bilayer-based NFs. Thus, study suggests that developed PLA/PVA-PEG NFs could be a promising candidate for tissue regeneration and food edible packaging in particular when impregnated with both CMO/GNS.

High efficient synthesis of benzyl lactate through waste PLA alcoholysis by protic ionic salt

Benzyl lactate (BL) is a critical reagent in pharmaceutical and chemical synthesis due to its versatility. Traditional synthesis of BL was constrained by the high cost and low yield, thereby hindering the feasibility of large-scale production. Here, we reported a novel synthesis strategy for BL by utilizing the alcoholysis of waste polylactic acid (PLA) by benzyl alcohol with the protic ionic salt, HTBD-OAc, as the catalyst. The gram-scale experiments achieved a 94.9 % yield, and the robustness of this reaction was evidenced by the yield maintaining 92.5 % across six recycling experiments. More impressively, kilogram-scale synthesis facilitated a complete conversion of PLA to BL, achieving an unprecedented yield of 98.7 % at 180 °C within two hours. The exceptional catalytic efficiency of this reaction is attributed to the synergistic functions between the HTBD+ cation and OAc− anion in the catalyst HTBD-OAc. This study heralds a significant stride towards the sustainable and scalable production of high-purity benzyl lactate, paving the way for extended industrial applicability for this essential compound.

Bone regeneration in rabbit cranial defects: 3D printed polylactic acid scaffolds gradually enriched with marine bioderived calcium phosphate

ObjectiveThis study aimed to evaluate the in vivo biocompatibility, mechanical performance and osteoconductive potential of 3D-printed polylactic acid (PLA) scaffolds enriched with marine bioderived calcium phosphate (bioCaP) for bone tissue engineering. Materials and MethodsPLA-bioCaP composite scaffolds were specifically designed for the rabbit cranial defect model by 3D printing, with a uniform distribution of open square-shaped pores and contributions in bioCaP. Physicochemical and mechanical characterization and the evaluation of biological response are presented. ResultsThe scaffolds demonstrated mechanical properties comparable to human bones, integration with the host bone, and osteoconductive behavior promoting cell ingrowth from the defect edge. Strong mineralized tissue ingrowth through the scaffolds’ pores was observed, providing notable support to the host bone. In quantitative terms, micro-CT and histomorphometry analysis post-implantation revealed no significant differences in bone regeneration across all groups. ConclusionThe 3D-printed scaffolds with perpendicular patterning, open porosity, and proposed composition displayed satisfactory mechanical properties, biocompatibility, and osteoconductive response. The scaffolds promoted bone regeneration at similar levels as the PLA. The highest contribution of bioCaP promoted a positive influence in certain histomorphometric parameters; however, it did not significantly improve their osteogenic capability. Further research is required to optimize scaffold composition and enhance their osteogenic potential. Clinical RelevanceThis study presents a significant advancement in bone tissue engineering through the development of personalized composite scaffolds for bone-related applications. The clinical implications of this research are profound, especially considering the increasing demand for functional bone regeneration technologies capable of producing cost-effective producing cost-effective customized scaffolds.

Environmentally friendly approaches for tailoring interfacial adhesion and mechanical performance of biocomposites based on poly(lactic acid)/rice straw.

In the present research, plant-based biocomposites containing poly(lactic acid) (PLA) and rice straw (RS) as an annually renewable agricultural waste were studied. To enhance the properties of these filled systems, two environmentally friendly pulping methods were applied to remove the non-cellulosic components of RS and fibrillate the fibers. In addition, two reactive compatibilizers based on functional epoxy and maleic anhydride groups were incorporated into the biocomposites, using a reactive extrusion process. By pulping the RS fibers and modifying the PLA/lignocellulosic filler interface, the plant-based biocomposites with enhanced performance were attained. Furthermore, the elastic modulus, tensile strength, tensile toughness, impact strength, hardness, density and Vicat softening point of PLA and filled PLA system with untreated RS were improved. The impact resistance, tensile strength and elastic modulus of neat PLA were enhanced by 40 %, 160 % and 100 % for the modified biocomposites containing the environmentally friendly RS pulps. The obtained results showed that, these biocomposites had even higher mechanical performance than the PLA biocomposites containing RS pulp obtained through common soda-pulping method. The reasons behind these improvements are the partial pulping of RS, as well as the chain extension of PLA macromolecules and PLA grafting onto the lignocellulosic fiber surfaces induced by the reactive compatibilizers.

Continuous fiber printing of a modular heater for ion mobility spectrometry

Ion mobility spectrometry (IMS) is a powerful analytical method for separating and detecting gaseous substances like volatile organic compounds (VOCs). It is highly versatile, used both as a standalone technique and in combination with chromatographic methods for pre-separation or mass spectrometry for complex matrix analysis. This study explores the use of an advanced 3D printing technology to print a heater for an IMS-device.A continuous fiber printer, commonly used to enhance the mechanical properties of printed objects, was used to create a customized heating element by embedding a copper wire within the polymer matrix during the printing process. Cyclic olefin copolymer (COC) was chosen as the matrix material due to its analytical properties, such as low off-gassing and higher thermal stability, compared to the more commonly used polylactic acid (PLA).The 3D printed heater was incorporated into a drift tube ion mobility spectrometer, and its performance was evaluated by analyzing the separation of various ketones. The results show that the 3D printed heater effectively controlled the temperature within the drift tube, improving the resolving power of overlapping peaks.This study shows the potential of 3D printing technology to improve fabrication and functionality of IMS devices. The flexibility in design and material selection afforded by 3D printing not only enhances the analytical performance of IMS but also allows for customization and rapid prototyping of other analytical instruments or laboratory devices.

Preparation and Characterization of Waste Cotton Fabric Reinforced Polylactic Acid Green Composites with Multifunctional Properties in a Low-Carbon Process

The development and design of eco-friendly materials prove crucial for promoting the recycling of waste cotton textiles and reducing environmental pollution. In this study, waste cotton fabric (WCF) and polylactic acid (PLA) serve to produce cotton fabric-reinforced PLA composite material (CF/P). The CF/P is then integrated with traditional porous sound-absorbing materials to create a novel composite plate. This research highlights the potential of WCF reinforced plates for sound absorption and thermal insulation applications in the construction field of construction and reports the effects of variables such as hot pressing temperature, WCF mass fraction, and WCF layer alignment angle on the material properties. The optimum tensile strength, water absorption, and thermal conductivity of the prepared CF/P are 64.2 ± 1.8MPa, 1.98% ± 0.04%, and 0.03W/(m·K), respectively. By combining with porous sound-absorbing materials and modifying the layering structure of composite plates, its acoustic performance can be adjusted. The highest Sound Absorption Average (SAA) of plates with a multilayer composite structure is 0.67. Direct shaping through hot pressing diminishes the use of adhesives, thereby reducing costs and health hazards. This approach offers a practical and efficient solution for the recycling and repurposing of natural fibers.

Contact Antibacterial and Biocompatible Polymeric, Composite with Copper Zeolite Filler and Copper Oxide, Nanoparticles: A Step Towards New Raw Materials for the Biomedical Industry

This paper introduces a simple procedure for developing composite materials with antibacterial and biocompatible properties using polylactic acid (PLA) and polypropylene (PP). These composites incorporate three variants of zeolites in different percentages as filler agents: pure zeolite (PZ), copper ion-saturated zeolite (LZ), and copper-ion-saturated zeolite with copper oxide nanoparticles (LZ-nCu). The composites were prepared by the extrusion method and manufactured by injection molding. The impact of these zeolites on various material properties was evaluated, including morphology, thermal stability, mechanical properties, antibacterial capacity, biocompatibility, water absorption, and chemical resistance. The results demonstrated that (i) the incorporation of zeolite into the PP matrix improved thermal stability and increased the tensile modulus of the composites. For PLA-based composites, although there was a slight decrease in these values compared to pure PLA, they remained within acceptable ranges; (ii) zeolite LZ and LZnCu composites at 5 and 10% by weight effectively inhibited the growth of Gram-positive and Gram-negative bacteria within a maximum of 2 hours of contact; and (iii) composites containing 10% by weight of PZ, LZ, or LZ-nCu showed reduced mechanical properties due to a tendency to form agglomerates. Additionally, LZ and LZ-nCu composites with the same percentage proved highly toxic to human gingival fibroblast cells (HGFs). PLA/LZ-nCu at 5% and PP/LZ at 5% composites exhibited antibacterial properties with bactericidal effects upon contact, high biocompatibility, and lower water absorption compared to the pure polymeric matrix. These results highlight the operational effectiveness of the procedure and suggest the potential of these composites in biomedical applications, such as in vitro dentistry, without contamination risks.

Role of crosslinkers in advancing chitosan-based biocomposite scaffolds for bone tissue engineering: A comprehensive review.

Bone tissue engineering (BTE) aims to repair and regenerate damaged bone tissue by combining cells, scaffolds, and signaling molecules. Various macromolecules, including natural polymers like chitosan (CS), collagen, hyaluronic acid, and alginate, as well as synthetic polymers such as polyethylene glycol and polylactic acid, are used in scaffold fabrication. Among these, CS holds significant potential in BTE due to its biocompatibility, biodegradability, and other features. The inherent mechanical weaknesses of CS-based scaffolds require the implementation of crosslinking strategies to improve their stability and overall performance. Physical crosslinkers like ultra-violet irradiation and freeze-thaw cycles are biocompatible but offer limited mechanical strength. Chemical crosslinkers like glutaraldehyde significantly improve mechanical strength, but they may induce cytotoxicity. We briefly outline here the critical role of physical and chemical crosslinkers in improving the physicochemical properties, mechanical strength, biocompatibility, and biological functions of CS-based scaffolds, including effective bone regeneration. The influence of crosslinking on the CS-based scaffolds' bioactivity, including the controlled release of bioactive molecules, is also discussed. A thorough understanding of crosslinker chemistry and application in CS-based scaffolds is essential for advancing bone regeneration therapies.

Insights into the photosensitivity and photobleaching of dissolved organic matter from microplastics: Structure-activity relationship and transformation mechanism

Revealing the structure-activity relationship between physicochemical properties and photoactivities of microplastic dissolved organic matter (MPDOM) is significant for understanding the environmental fate of MPs. Here, we systematically analyzed the physicochemical properties and molecular composition of DOM derived from MPs including polystyrene (PS), polyethylene glycol terephthalate (PET), polyadipate/butylene terephthalate (PBAT), polylactic acid (PLA), polypropylene (PP), and compared their photosensitivity and photobleaching behaviors. Results indicated that PSDOM and PETDOM had more similar properties and compositions, and showed stronger photosensitivity and photobleaching effects than PBATDOM, PLADOM and PPDOM. The [3DOM∗]SS and [1O2]SS varied in the range of 0.31-13.03 × 10-14 and 1.71-5.49 × 10-13M, respectively, which were within the reported range of DOM from other sources. The SUVA254, HIX, AImodwa, Xcwa and lignin/CRAM-like component showed positive correlation with the [3DOM∗]SS, [1O2]SS and Φ3DOM*. The negative correlation between E2/E3 and [3DOM∗]SS was due to the higher proportion of low-molecular weight components in MPDOM. The lignin/CRAM-like component was identified to be the crucial photobleaching-component. The lignin/CRAM-like in PSDOM showed a deepened oxidation degree, while its change trend in PETDOM was from unsaturated to saturated. These findings provide new insights into the relevant photochemical fate of MPDOM.

A novel sustainable wood-based negative air anion generator utilizing in-situ polymerization of polylactic acid to reinforce the cellulose framework

The generation of negative air ions (NAI) by furniture contributes to indoor air purification and enhances the living environment. However, commercially available furniture typically relies on surface coatings to release NAI. Over time, the degradation of these coatings leads to a significant decline in NAI release performance, presenting a persistent challenge for sustained effectiveness. Here, a novel sustainable wood-based negative air anion generator (SWNG) had been developed, utilizing a cellulose framework as the substrate. The in-situ synthesis of polylactic acid (PLA) within the wood incorporated titanium dioxide (TiO2), tourmaline (TL), and cellulose acetate, firmly anchoring these materials within the wood structure. Compared to the cellulose framework alone, the NAI production of the SWNG had increased by 406.67 %. The impregnation with PLA enhanced the enduring photocatalytic activity of TiO2 and TL in this innovative wooden NAI generator. After undergoing 200 cycles of testing between −40 °C and 50 °C, it continued to sustain NAI production, demonstrating exceptional antibacterial performance. Overall, this study introduced a novel sustainable wood-based negative air ion generator as a highly stable material with sustainable properties, offering significant potential for applications in improving indoor air quality and in the domain of home construction.

Enhancing the oil/water separation efficiency of polylactic acid fiber membrane via polydimethylsiloxane-polycaprolactone copolymer

Membrane technology is one of the important methods of treating oily wastewater due to low energy consumption. How to design the membrane with high efficiency, biodegradable, reusable and good mechanical properties has attracted increasing interest. In this work, a polydimethylsiloxane-polycaprolactone (PDMS- PCL) was synthesized to endow polylactic acid (PLA) fiber membrane with superhydrophobicity and superoleophilicity via electrospinning without secondary processing. When the blend ratio of PDMS-PCL/PLA is 15wt%, the water contact angle of the fiber membrane is 155.1 ± 3°, and the oil contact angle is almost zero. The tensile strength and elongation at break are 2.05 ± 0.16MPa and 37.9 ± 2.3%, respectively. The fiber membrane exhibited high oil/water separation performance and quick adsorption of oil drop underwater. The permeate flux and separation efficiency for n-hexane are 3550 ± 50L·m-2·h-1 and 99.3 ± 0.2%, separately. It also has excellent self-cleaning and durable properties. The fiber membrane maintains high oil flux, separation efficiency, and mechanical properties after more than 10 rounds of separation. The fiber membrane can resist the external environment variation such as to some extent. The water contact angle of the fiber membrane undergoing friction and heating at 100 °C stably remains at about 150°. The weight loss is little in salt solution. Then this simple efficient method is suitable large-scale production and will promote membrane technologies in application of oil/water separation.

Realization of the shape memory effect in a composite material PLA/Diopside with different supramolecular structures

This study explores the realization of the shape memory effect (SME) in composite materials composed of polylactide (PLA) filled with diopside particles exhibiting varied supramolecular structures, such as spherulites and amorphous lamellar structures. We investigated the influence of diopside filler on the thermomechanical properties and shape recovery behavior of PLA-based composites. Different supramolecular structures of PLA were achieved through controlled crystallization processes. Comprehensive characterization techniques, including differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA), were employed to elucidate the structure-property relationships. The results indicate that the diopside enhances the SME of PLA composites, with the degree of improvement being dependent on the specific supramolecular structure of the polymer matrix. Our findings provide insights into the design of advanced SMPs with tailored properties for potential applications in medicine.

Fabrication of highly flame retardancy and impact strength polylactide foams with phosphorus-containing and agricultural waste-derived multifuctional additives

Research on green polymeric foams is crucial for sustainable development. A polylactide (PLA) foam with a bio-based multifunctional flame-retardant additive derived from agricultural waste was developed and evaluated. Various PLA-based foams were prepared using melt extrusion. A PLA foam with 10 phr of trioctyl phosphate (TOP) showed enhanced crystallization ability, desirable impact strength, and excellent flame retardancy. However, TOP presents concerns for health and the environment. Therefore, bio-based flame retardants (BFRs) derived from agricultural waste were used to partially replace TOP and support the environment friendly and sustainable practices of the bio-circular-green (BCG) economic model. The study used a combination of 2.5 phr of pumpkin shell powder (PK) and 7.5 phr of TOP to produce a PLA foam that achieved a UL-94 V-0 rating, indicating excellent flame retardancy. The impact strength of this foam was about 84 % greater than that of neat PLA foam. The successful incorporation of agricultural waste-derived additives in PLA foam could not only contribute to sustainability but also add value to agricultural waste by repurposing it for a useful application.

Highly air-permeable and dust-holding protective membranes by hierarchical structuring of electroactive poly(lactic acid) micro- and nanofibers

The application of biodegradable electrospun poly(lactic acid) (PLA) fibrous membranes (FMs) toward respiratory protection has long been dwarfed by the poor electret effect and short service life. Herein, a micro-on-nano (MON) approach was proposed to fabricate highly electroactive dual-scale poly(lactic acid) (DS-PLA) FMs consisting of inner-layer nanofibers (667nm) and outer-layer microfibers (1.22µm). Customized Ag-decorated BTO (Ag-BTO) dielectrics were incorporated to improve the electret effect and charge storage stability of DS-PLA FMs, contributing to the improved dielectric constants (1.40), surface potential (11.4kV), and triboelectric performance (output voltage of 34.2V at 10N, 0.5Hz). The unique hierarchies and profound electrostatic adsorption effect synergistically allowed the DS-PLA FMs to achieve high PM filtration efficiencies (99.10% for PM2.5, 90.37% for PM0.3, 32L/min) at a reduced pressure drop (only 58.8Pa). Furthermore, benefiting from the cascade filtration mechanisms, the DS-PLA FMs demonstrated superior dust holding capacity (9.4g/m2), which was 3.2 times higher than that of normal PLA. With the assistance of convolutional neural network (CNN), a set of breathing patterns could be recognized with a classification accuracy as high as 96.7%. This work provides a facile pathway to significantly prolong the service life of electrospun PLA filters for high-performance air filtration and deep learning-assisted respiratory monitoring.

Synthesis of Renewable and Seawater-degradable Polyesters Based on a Fully Biobased Diester

The design and development of biobased plastics that can degrade in seawater is a potential approach to address the seawater pollution of fossil plastics. Herein, N,N'-pentamethylene-bis(pyrrolidone-4-methyl carboxylate) (PBPC), a biobased diester with two pyrrolidone rings, was synthesized from renewable 1,5-pentanediamine and dimethyl itaconate. PBPC was polymerized with three α,ω-diols to prepare biobased homopolyesters with number-average molecular weight (Mn) around 25 kDa. These amorphous homopolyesters presented remarkable UV shielding abilities compared with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS). Incubation experiments in artificial seawater for 150 days indicated that the homopolyesters based on PBPC exhibited rapid seawater-degradability. Then, PBPC was copolymerized with 1,4-butanediol and terephthalic acid to prepare a series of copolyesters with Mn around 20 kDa. The introduction of PBPC into poly(butylene terephthalate) (PBT) resulted in the elevated toughness and sensitivity to seawater degradation. Depending on the composition of PBPC, the thermal, mechanical, and degradation rate of the copolyesters were adjustable. Overall, the PBPC-based polyesters are promising alternatives to commercial packaging materials in improving the renewability of raw materials and achieving seawater degradation.

Pyrolysis kinetic analysis of molten bioplastics based on the combination of real-time characterization and Guassian deconvolution: Case study of poly(lactic acid) materials.

Pyrolysis remains a promising method for the utilization of biogradable plastics. However, the kinetics and mechanisms of molten polymer pyrolysis are not well understood, and the effect of additives (mainly inorganic nucleating agents) on the reaction pathway has not been widely explored. In this work, we conducted a method using the thermogravimetric analysis-Fourier transform infrared spectrometry (TG-FTIR) combined with a model-fitting method, instead of a traditional method subjectively selecting a reaction model. The FTIR curves provided information for sub-reaction determination, and the detailed parameters were determined using Gaussian deconvolution. The calculation results revealed that the whole process of poly(latic acid) (PLA) pyrolysis is the random nucleation and nuclei growth model. The introduction of inorganic nucleating agents provided nuclei for PLA decomposition, decreasing the initial activation energy (E) from approximately 136kJ·mol-1 to 88 and 79kJ·mol-1 at a conversion rate of 0.01. However, the nucleating agent could hinder the generation of nuclei from PLA ontology, which led to the increase of E value after the nucleating agents were occupied.

3D printed TC4 titanium alloy bone scaffolds with TNTs-VA-PLGA composite coating on the surface:improved infection resistance and biocompatibility

Titanium-based bone scaffolds are prone to aseptic infection and loosening after implantation,which seriously limits their clinical applications. Preparation of titanium dioxide nanotubes (TNTs) on the surface of the scaffolds and loading of anti-infective drugs is an effective method to solve this problem, but the current TNTs prepared on the surface of titanium-based scaffolds have a high internal and external variability in morphology and low drug loading capacity. In this study, we prepared TNTs on the surface of three kinds of TC4 titanium alloy scaffolds with TPMS structure with controllable morphology, tube diameter of 90-125 nm and tube length of 14-35 μm,and the difference between inner and outer diameters of the tubes was less than 2 μm,and the drug released from the composite scaffolds was maintained at a concentration of more than 1.5 μg/ml within 11 days after loading anti-infective drug Vancomycin-polylactic acid-hydroxyacetic acid copolymer(VA-PLGA) on the surface of the TNTs. Based on the simulation of drug release, the TNTs-VA-PLGA drug delivery system conforms to the Korsmeyer-Peppas model. Cell experiments confirmed that the composite scaffolds significantly increased cell proliferation by 65.33% compared with the unmodified scaffolds. The results indicated that the TNTs coating containing vancomycin and polylactic acid-hydroxyacetic acid copolymer had a promising application in orthopedic implants.

Preparation of disulfiram-Cu2+-polylactide nanofibrous membranes via electrostatic spinning and evaluation of their in vitro anticancer effects

The antitumor effects of disulfiram (DSF) —a conventional medication used to treat alcohol dependence—have been documented in numerous studies. However, because of its low water solubility and Cu2+-dependent anticancer effects, the application of DSF in cancer therapy has been limited. Nanofibrous membranes produced via electrospinning have large specific surface areas. Consequently, they have been extensively used in biomedical applications, such as tissue scaffolding, drug delivery. In this study, a polylactic acid nanofibrous membrane was designed to encapsulate Cu2+ and DSF. The encapsulated drug was released when the membranes came into contact with the tumor tissue. DSF functioned as a Cu-ion carrier and combined with Cu2+ to induce tumor-cell apoptosis. The anticancer properties of the drug-loaded nanofibrous membrane were verified at the cellular level using in vitro experiments with cells. The results indicated that DSF and Cu2+ were released from the fiber membrane, and the combination of DSF and Cu2+ exhibited a better of cancer are proposed.