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Polylactic acid (PLA) is a thermoplastic polymer produced from lactic acid that has been chiefly utilized in biodegradable material and as a composite matrix material. PLA is a prominent biomaterial that is widely used to replace traditional petrochemical-based polymers in various applications owing environmental concerns. Green composites have gained greater attention as ecological consciousness has grown since they have the potential to be more appealing than conventional petroleum-based composites, which are toxic and nonbiodegradable. PLA-based composites with natural fiber have been extensively utilized in a variety of applications, from packaging to medicine, due to their biodegradable, recyclable, high mechanical strength, low toxicity, good barrier properties, friendly processing, and excellent characteristics. A summary of natural fibers, green composites, and PLA, along with their respective properties, classification, functionality, and different processing methods, are discussed to discover the natural fiber-reinforced PLA composite material development for a wide range of applications. This work also emphasizes the research and properties of PLA-based green composites, PLA blend composites, and PLA hybrid composites over the past few years. PLA’s potential as a strong material in engineering applications areas is addressed. This review also covers issues, challenges, opportunities, and perspectives in developing and characterizing PLA-based green composites.

Over recent years, enthusiasm towards the manufacturing of biopolymers has attracted considerable attention due to the rising concern about depleting resources and worsening pollution. Among the biopolymers available in the world, polylactic acid (PLA) is one of the highest biopolymers produced globally and thus, making it suitable for product commercialisation. Therefore, the effectiveness of natural fibre reinforced PLA composite as an alternative material to substitute the non-renewable petroleum-based materials has been examined by researchers. The type of fibre used in fibre/matrix adhesion is very important because it influences the biocomposites’ mechanical properties. Besides that, an outline of the present circumstance of natural fibre-reinforced PLA 3D printing, as well as its functions in 4D printing for applications of stimuli-responsive polymers were also discussed. This research paper aims to present the development and conducted studies on PLA-based natural fibre bio-composites over the last decade. This work reviews recent PLA-derived bio-composite research related to PLA synthesis and biodegradation, its properties, processes, challenges and prospects.

Triamcinolone acetonide extended-release (ER) 32 mg (Zilretta ® ) is approved in the USA for the management of osteoarthritis (OA) pain of the knee and is administered as a single, 5 mL intra-articular (IA) injection. Although the therapeutic effects from IA corticosteroids are typically short-lived, triamcinolone acetonide ER is formulated in poly (lactic-co-glycolic acid) (PLGA) microspheres that slowly release triamcinolone acetonide in the synovium, enabling their prolonged presence in the joint. This reduces systemic exposure and lessens corticosteroid-related systemic adverse reactions, such as blood glucose elevations. In a 24-week, randomized, phase III clinical trial, triamcinolone acetonide ER 32 mg significantly improved mean average daily pain intensity in patients with knee OA relative to placebo, and pain, stiffness and physical function (according to WOMAC criteria) relative to placebo and triamcinolone acetonide crystalline suspension (CS). Triamcinolone acetonide ER was generally well tolerated, with a tolerability profile similar to that of triamcinolone acetonide CS and placebo. Findings from a single-arm phase IIIb study indicated that a repeat administration of triamcinolone acetonide ER may be similarly efficacious to an initial injection without having deleterious effects on cartilage or other aspects of joint structure. Thus, triamcinolone acetonide ER expands the treatment options available for the management of OA pain of the knee.

Administration of drugs via the buccal route has attracted much attention in recent years. However, developing systems with satisfactory adhesion under wet conditions and adequate drug bioavailability still remains a challenge. Here, we propose a mussel-inspired mucoadhesive film. Ex vivo models show that this film can achieve strong adhesion to wet buccal tissues (up to 38.72 ± 10.94 kPa). We also demonstrate that the adhesion mechanism of this film relies on both physical association and covalent bonding between the film and mucus. Additionally, the film with incorporated polydopamine nanoparticles shows superior advantages for transport across the mucosal barrier, with improved drug bioavailability (~3.5-fold greater than observed with oral delivery) and therapeutic efficacy in oral mucositis models (~6.0-fold improvement in wound closure at day 5 compared with that observed with no treatment). We anticipate that this platform might aid the development of tissue adhesives and inspire the design of nanoparticle-based buccal delivery systems. Minimally invasive drug delivery is of wide interest and oral tissue is an attractive target for this. Here, the authors report on the creation of mussel-inspired films for retention on the wet oral tissue for the delivery of drugs by diffusion and transport though the mucosal tissue.

Different from other 3D printing techniques such as selective laser sintering (SLS), stereolithography (SLA), three-dimensional printing (3DP), and laminated object manufacturing (LOM), the fused deposition modeling (FDM) technology is widely used in aerospace, automobile making, bio-medicals, smart home, stationery and training aids, and creative gifts for its easy use, simple operation, and low cost. The polylactic acid (PLA) is a material most extensively applied in FDM technology for its low melting point, non-poison, non-irritation, and sound biocompatibility. The FDM 3D-printed PLA parts are a research hotspot in the 3D printing field. This paper is intended to sum up the latest research results and achievements made in recent years in the interface bonding property, mechanical properties, and shape precision promotion of FDM 3D-printed PLA parts as well as the functional expansion of the PLA parts based on vast domestic and overseas literature. The literature research collection focuses on the following two aspects: one is the macroscopic technical research on the optimal settings of key technological parameters; the other one is the PLA modification research on improvement of cross-linking state and crystallinity of PLA molecular chains, carbon reinforced phase modification of PLA, and PLA functional compound modification. The researches in the two aspects are of importance in improving whole properties, enhancing functional applications, and expanding and enriching the applications of FDM 3D-printed PLA parts. This paper is expected to give some helps and references to the researchers who are specializing in the 3D printing field.

Radiofrequency ablation (RFA) is clinically adopted to destruct solid tumors, but is often incapable of completely ablating large tumors and those with multiple metastatic sites. Here we develop a CaCO 3 -assisted double emulsion method to encapsulate lipoxidase and hemin with poly(lactic-co-glycolic acid) (PLGA) to enhance RFA. We show the HLCaP nanoreactors (NRs) with pH-dependent catalytic capacity can continuously produce cytotoxic lipid radicals via the lipid peroxidation chain reaction using cancer cell debris as the fuel. Upon being fixed inside the residual tumors post RFA, HLCaP NRs exhibit a suppression effect on residual tumors in mice and rabbits by triggering ferroptosis. Moreover, treatment with HLCaP NRs post RFA can prime antitumor immunity to effectively suppress the growth of both residual and metastatic tumors, also in combination with immune checkpoint blockade. This work highlights that tumor-debris-fueled nanoreactors can benefit RFA by inhibiting tumor recurrence and preventing tumor metastasis. Radiofrequency ablation (RFA) is a minimally invasive tumor ablation method, however incomplete ablation and the induction of an immunosuppressive microenvironment limit its efficacy in the clinic. Here the authors design a pH-responsive lipoxidase-loaded nanoreactor, that by triggering ferroptosis and anti-tumor immunity, amplify the therapeutic benefits of RFA in preclinical models.

Polylactic acid (PLA) is produced from renewable materials, has a low melting temperature and has a low carbon footprint. These advantages have led to the extensive use of polylactic acid in additive manufacturing, particularly by fused filament fabrication (FFF). PLA parts that are 3D printed for industrial applications require stable mechanical properties and predictability regarding their dependence on the process parameters. Therefore, the development of the FFF process has been continuously accompanied by the development of software packages that generate CNC codes for the printers. A large number of user-controllable process parameters have been introduced in these software packages. In this respect, a lot of articles in the specialized literature address the issue of the influence of the process parameters on the mechanical properties of 3D-printed specimens. A systematic review of the research targeting the influence of process parameters on the mechanical properties of PLA specimens additively manufactured by fused filament fabrication was carried out by the authors of this paper. Six process parameters (layer thickness, printing speed, printing temperature, build plate temperature, build orientation and raster angle) were followed. The mechanical behavior was evaluated by tensile, compressive and bending properties.

Additive manufacturing (AM) is a promising technology for the rapid tooling and fabrication of complex geometry components. Among all AM techniques, fused filament fabrication (FFF) is the most widely used technique for polymers. However, the consistency and properties control of the FFF product remains a challenging issue. This study aims to investigate physical changes during the 3D printing of polylactic acid (PLA). The correlations between the porosity, crystallinity and mechanical properties of the printed parts were studied. Moreover, the effects of the build-platform temperature were investigated. The experimental results confirmed the anisotropy of printed objects due to the occurrence of orientation phenomena during the filament deposition and the formation both of ordered and disordered crystalline forms (α and δ, respectively). A heat treatment post-3D printing was proposed as an effective method to improve mechanical properties by optimizing the crystallinity (transforming the δ form into the α one) and overcoming the anisotropy of the 3D printed object.

With emerging supremacy, cancer immunotherapy has evolved as a promising therapeutic modality compared to conventional antitumor therapies. Cancer immunotherapy composed of biodegradable poly(lactic- co -glycolic acid) (PLGA) particles containing antigens and toll-like receptor ligands induces vigorous antitumor immune responses in vivo. Here, we demonstrate the supreme adjuvant effect of the recently developed and pharmaceutically defined double-stranded (ds)RNA adjuvant Riboxxim especially when incorporated into PLGA particles. Encapsulation of Riboxxim together with antigens potently activates murine and human dendritic cells, and elevated tumor-specific CD8 + T cell responses are superior to those obtained using classical dsRNA analogues. This PLGA particle vaccine affords primary tumor growth retardation, prevention of metastases, and prolonged survival in preclinical tumor models. Its advantageous therapeutic potency was further enhanced by immune checkpoint blockade that resulted in reinvigoration of cytotoxic T lymphocyte responses and tumor ablation. Thus, combining immune checkpoint blockade with immunotherapy based on Riboxxim-bearing PLGA particles strongly increases its efficacy. PLGA based cancer immunotherapy incorporating antigen and TLR ligands has resulted in enhancement of the anti-tumour response. Here, the authors explore the use of a defined double stranded RNA adjuvant, Riboxxim, and test its incorporation with PLGA immunotherapy in the context of in vivo tumour models and show enhanced induction of the anti-tumour response.

Acute kidney injury (AKI) caused by sepsis is a serious disease which mitochondrial oxidative stress and inflammatory play a key role in its pathophysiology. Ceria nanoparticles hold strong and recyclable reactive oxygen species (ROS)-scavenging activity, have been applied to treat ROS-related diseases. However, ceria nanoparticles can't selectively target mitochondria and the ultra-small ceria nanoparticles are easily agglomerated. To overcome these shortcomings and improve therapeutic efficiency, we designed an ROS-responsive nano-drug delivery system combining mitochondria-targeting ceria nanoparticles with atorvastatin for acute kidney injury. : Ceria nanoparticles were modified with triphenylphosphine (TCeria NPs), followed by coating with ROS-responsive organic polymer (mPEG-TK-PLGA) and loaded atorvastatin (Atv/PTP-TCeria NPs). The physicochemical properties, drug release profiles, mitochondria-targeting ability, antioxidant, anti-apoptotic activity and treatment efficacy of Atv/PTP-TCeria NPs were examined. : Atv/PTP-TCeria NPs could accumulate in kidneys and hold a great ability to ROS-responsively release drug and TCeria NPs could target mitochondria to eliminate excessive ROS. study suggested Atv/PTP-TCeria NPs exhibited superior antioxidant and anti-apoptotic activity. study showed that Atv/PTP-TCeria NPs effectively decreased oxidative stress and inflammatory, could protect the mitochondrial structure, reduced apoptosis of tubular cell and tubular necrosis in the sepsis-induced AKI mice model. This ROS-responsive nano-drug delivery system combining mitochondria-targeting ceria nanoparticles with atorvastatin has favorable potentials in the sepsis-induced AKI therapy.