Application of PLGA as a Biodegradable and Biocompatible Polymer for Pulmonary Delivery of Drugs

3D cryo-printed hierarchical porous scaffolds provide immobilization of surface-functionalized sleep-inspired small extracellular vesicles: synergistic therapeutic strategies for vascularized bone regeneration based on macrophage phenotype modulation and angiogenesis-osteogenesis coupling

Bone defect healing is a multi-factorial process involving the inflammatory microenvironment, bone regeneration and the formation of blood vessels, and remains a great challenge in clinical practice. Combined use of three-dimensional (3D)-printed scaffolds and bioactive factors is an emerging strategy for the treatment of bone defects. Scaffolds can be printed using 3D cryogenic printing technology to create a microarchitecture similar to trabecular bone. Melatonin (MT) has attracted attention in recent years as an excellent factor for promoting cell viability and tissue repair. In this study, porous scaffolds were prepared by cryogenic printing with poly(lactic-co-glycolic acid) and ultralong hydroxyapatite nanowires. The hierarchical pore size distribution of the scaffolds was evaluated by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Sleep-inspired small extracellular vesicles (MT-sEVs) were then obtained from MT-stimulated cells and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)-inorganic pyrophosphate (DSPE-PEG-PPi) was used to modify the membrane of MT-sEVs to obtain PPi-MT-sEVs. RNA sequencing was performed to explore the potential mechanisms. The results demonstrated that PPi-MT-sEVs not only enhanced cell proliferation, migration and angiogenesis, but also regulated the osteogenic/adipogenic fate determination and M1/M2 macrophage polarization switch in vitro. PPi-MT-sEVs were used to coat scaffolds, enabled by the capacity of PPi to bind to hydroxyapatite, and computational simulations were used to analyze the interfacial bonding of PPi and hydroxyapatite. The macrophage phenotype-modulating and osteogenesis-angiogenesis coupling effects were evaluated in vivo. In summary, this study suggests that the combination of hierarchical porous scaffolds and PPi-MT-sEVs could be a promising candidate for the clinical treatment of bone defects.

Osteoconductive composite membranes produced by rotary jet spinning bioresorbable PLGA for bone regeneration

Bone defects and injuries are common, and better solutions are needed for improved regeneration and osseointegration. Bioresorbable membranes hold great potential in bone tissue engineering due to their high surface area and versatility. In this context, polymers such as poly(lactic-co-glycolic acid) (PLGA) can be combined with osteoconductive materials like hydroxyapatite (HA) nanoparticles (NPs) to create membranes with enhanced bioactivity and bone regeneration. Rotary Jet spinning (RJS) is a powerful technique to produce these composite membranes. This study presents an innovative and efficient method to obtain PLGA-HA(NPs) membranes with continuous fibers containing homogeneous HA(NPs) distribution. The membranes demonstrated stable thermal degradation, allowing HA(NPs) quantification. In addition, the PLGA-HA(NPs) presented osteoconductivity, were not cytotoxic, and had high cell adhesion when cultured with pre-osteoblastic cells. These findings demonstrate the potential of RJS to produce PLGA-HA(NPs) membranes for easy and effective application in bone regeneration.

Biliary stents for active materials and surface modification: Recent advances and future perspectives

Demand for biliary stents has expanded with the increasing incidence of biliary disease. The implantation of plastic or self-expandable metal stents can be an effective treatment for biliary strictures. However, these stents are nondegradable and prone to restenosis. Surgical removal or replacement of the nondegradable stents is necessary in cases of disease resolution or restenosis. To overcome these shortcomings, improvements were made to the materials and surfaces used for the stents. First, this paper reviews the advantages and limitations of nondegradable stents. Second, emphasis is placed on biodegradable polymer and biodegradable metal stents, along with functional coatings. This also encompasses tissue engineering & 3D-printed stents were highlighted. Finally, the future perspectives of biliary stents, including pro-epithelialization coatings, multifunctional coated stents, biodegradable shape memory stents, and 4D bioprinting, were discussed.

Targeted therapy with polymeric nanoparticles in PBRM1-mutant biliary tract cancers: Harnessing DNA damage repair mechanisms

Biliary tract cancers (BTCs) are aggressive malignancies with a dismal prognosis that require intensive targeted therapy. Approximately 10 % of BTCs have PBRM1 mutations, which impede DNA damage repair pathways and make cancer cells more susceptible to DNA-damaging chemicals. This review focus on development of poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles targeting delivery system to selectively deliver chemotherapy into PBRM1-deficient BTC cells. These nanoparticles improve therapy efficacy by increasing medication targeting and retention at tumour locations. In preclinical studies, pharmacokinetic profile of this nanoparticle was encouraging and supported its ability to achieve extended circulation time with high drug accumulation in tumor. The review also highlights potential of Pou3F3:I54N to expedite bioassays for patient selection in BTC targeted therapies.

Injectable drug-loaded thermosensitive hydrogel delivery system for protecting retina ganglion cells in traumatic optic neuropathy

Currently, generalized therapy for traumatic optic neuropathy (TON) is lacking. Various strategies have been developed to protect and regenerate retinal ganglion cells (RGCs) after TON. Intravitreal injection of supplements has been approved as a promising approach, although serious concerns, such as low delivery efficacy and pain due to frequent injections, remain. In this study, we tested an injectable thermosensitive hydrogel drug delivery system engineered to deliver ciliary neurotrophic factor (CNTF) and triamcinolone acetonide (TA). The results of rheological studies showed that the prepared drug-loaded hydrogel possessed a suitable mechanical modulus of ∼300 Pa, consistent with that of vitreum. The hydrogel exhibited thermosensitive with sustained drug release performance. In vitro co-culture of the CNTF-loaded hydrogel system with primary RGCs also induced significant axon regeneration, with 38.5% increase in neurite length, indicating the regenerative response of the thermosensitive hydrogel drug delivery system. A Sprague-Dawley rat optic nerve crush model was constructed and applied to determine the neuroprotective and regenerative capacities of the system. The results demonstrated that a single intravitreal injection of the drug-loaded hydrogel (PLGA-PEG-PLGA + TA or PLGA-PEG-PLGA + CNTF) significantly increased RGC survival at both 14 and 28 days. The RGC survival rate was 31.05 ± 1.41% for the drug-loaded hydrogel system (the control group was 16.79 ± 1.50%) at Day 28. These findings suggest that the injectable drug-loaded thermosensitive hydrogel delivery system is a promising therapeutic tool for treating optic nerve degeneration.

Modulating the Thermoresponsive Characteristics of PLGA-PEG-PLGA Hydrogels via Manipulation of PLGA Monomer Sequences

Hydrogels are promising materials for biomedical applications, particularly in drug delivery and tissue engineering. This study highlights thermoresponsive hydrogels, specifically poly(lactic-co-glycolic acid) (PLGA)-poly(ethylene glycol) (PEG)-PLGA triblock copolymers, and introduces a feed rate-controlled polymerization (FRCP) method. By utilizing an organic catalyst and regulating the monomer feed rate, the sequence distribution of PLGA within the triblock copolymer is controlled. Various analyses, including 13C NMR and rheological measurements, were conducted to investigate the impact of sequence distribution. Results show that altering sequence distribution significantly influences the sol-gel transition, hydrophobicity-hydrophilicity balance, and drug release profile. Increased sequence uniformity lowers the glass transition temperature, raises the sol-gel transition temperature due to enhanced hydrophilicity, and promotes a more uniform drug (curcumin) distribution within the PLGA domain, resulting in a slower release rate. This study emphasizes the importance of PLGA sequence distribution in biomedical applications and the potential of FRCP to tailor thermoresponsive hydrogels for biomedical advancements.

Advances in medical polyesters for vascular tissue engineering

Blood vessels are highly dynamic and complex structures with a variety of physiological functions, including the transport of oxygen, nutrients, and metabolic wastes. Their normal functioning involves the close and coordinated cooperation of a variety of cells. However, adverse internal and external environmental factors can lead to vascular damage and the induction of various vascular diseases, including atherosclerosis and thrombosis. This can have serious consequences for patients, and there is an urgent need for innovative techniques to repair damaged blood vessels. Polyesters have been extensively researched and used in the treatment of vascular disease and repair of blood vessels due to their excellent mechanical properties, adjustable biodegradation time, and excellent biocompatibility. Given the high complexity of vascular tissues, it is still challenging to optimize the utilization of polyesters for repairing damaged blood vessels. Nevertheless, they have considerable potential for vascular tissue engineering in a range of applications. This summary reviews the physicochemical properties of polyhydroxyalkanoate (PHA), polycaprolactone (PCL), poly-lactic acid (PLA), and poly(lactide-co-glycolide) (PLGA), focusing on their unique applications in vascular tissue engineering. Polyesters can be prepared not only as 3D scaffolds to repair damage as an alternative to vascular grafts, but also in various forms such as microspheres, fibrous membranes, and nanoparticles to deliver drugs or bioactive ingredients to damaged vessels. Finally, it is anticipated that further developments in polyesters will occur in the near future, with the potential to facilitate the wider application of these materials in vascular tissue engineering.

A Comprehensive Review of Nanoparticles: From Classification to Application and Toxicity

Nanoparticles are structures that possess unique properties with high surface area-to-volume ratio. Their small size, up to 100 nm, and potential for surface modifications have enabled their use in a wide range of applications. Various factors influence the properties and applications of NPs, including the synthesis method and physical attributes such as size and shape. Additionally, the materials used in the synthesis of NPs are primary determinants of their application. Based on the chosen material, NPs are generally classified into three categories: organic, inorganic, and carbon-based. These categories include a variety of materials, such as proteins, polymers, metal ions, lipids and derivatives, magnetic minerals, and so on. Each material possesses unique attributes that influence the activity and application of the NPs. Consequently, certain NPs are typically used in particular areas because they possess higher efficiency along with tenable toxicity. Therefore, the classification and the base material in the NP synthesis hold significant importance in both NP research and application. In this paper, we discuss these classifications, exemplify most of the major materials, and categorize them according to their preferred area of application. This review provides an overall review of the materials, including their application, and toxicity.

The Effect of Different Factors on Poly(lactic-co-glycolic acid) Nanoparticle Properties and Drug Release Behaviors When Co-Loaded with Hydrophilic and Hydrophobic Drugs

Poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) are versatile drug nanocarriers with a wide spectrum of applications owing to their extensive advantages, including biodegradability, non-toxic side effects, and low immunogenicity. Among the numerous nanoparticle preparation methods available for PLGA NPs (the hydrophobic polymer), one of the most extensively utilized preparations is the sonicated-emulsified solvent evaporation method, owing to its simplicity, speed, convenience, and cost-effectiveness. Nevertheless, several factors can influence the outcomes, such as the types of concentration of the surfactants and organic solvents, as well as the volume of the aqueous phase. The objective of this article is to explore the influence of these factors on the properties of PLGA NPs and their drug release behavior following encapsulation. Herein, PLGA NPs were fabricated using bovine serum albumin (BSA) as a surfactant to investigate the impact of influencing factors, including different water-soluble organic solvents such as propylene carbonate (PC), ethyl acetate (PA), and dichloromethane (DCM). Notably, the size of PLGA NPs was smaller in the EA group compared to that in the DCM group. Moreover, PLGA NPs showed excellent stability, ascribed to the presence of the BSA surfactant. Furthermore, PLGA NPs were co-loaded with varying concentrations of hydrophilic drugs (doxorubicin hydrochloride) and hydrophobic drugs (celecoxib), and exhibited pH-sensitive drug release behavior in PBS with pH 7.4 and pH 5.5.

Acellular dermal matrix in urethral reconstruction

The management of severe urethral stricture has always posed a formidable challenge. Traditional approaches such as skin flaps, mucosal grafts, and urethroplasty may not be suitable for lengthy and intricate strictures. In the past two decades, tissue engineering solutions utilizing acellular dermal matrix have emerged as potential alternatives. Acellular dermal matrix (ADM) is a non-immunogenic biological collagen scaffold that has demonstrated its ability to induce layer-by-layer tissue regeneration. The application of ADM in urethral reconstruction through tissue engineering has become a practical endeavor. This article provides an overview of the preparation, characteristics, advantages, and disadvantages of ADM along with its utilization in urethral reconstruction via tissue engineering.

Fatty Oil of Descurainia Sophia Nanoparticles Improve Monocrotaline-Induced Pulmonary Hypertension in Rats Through PLC/IP3R/Ca2+ Signaling Pathway

Purpose

Fatty oil of Descurainia Sophia (OIL) has poor stability and low solubility, which limits its pharmacological effects. We hypothesized that fatty oil nanoparticles (OIL-NPs) could overcome this limitation. The protective effect of OIL-NPs against monocrotaline-induced lung injury in rats was studied.

Methods

We prepared OIL-NPs by wrapping fatty oil with polylactic-polyglycolide nanoparticles (PLGA-NPs) and conducted in vivo and in vitro experiments to explore its anti-pulmonary hypertension (PH) effect. In vitro, we induced malignant proliferation of pulmonary artery smooth muscle cells (RPASMC) using anoxic chambers, and studied the effects of OIL-NPs on the malignant proliferation of RPASMC cells and phospholipase C (PLC)/inositol triphosphate receptor (IP3R)/Ca2+ signal pathways. In vivo, we used small animal echocardiography, flow cytometry, immunohistochemistry, western blotting (WB), polymerase chain reaction (PCR) and metabolomics to explore the effects of OIL-NPs on the heart and lung pathological damage and PLC/IP3R/Ca2+ signal pathway of pulmonary hypertension rats.

Results

We prepared fatty into OIL-NPs. In vitro, OIL-NPs could improve the mitochondrial function and inhibit the malignant proliferation of RPASMC cells by inhibiting the PLC/IP3R/Ca2+signal pathway. In vivo, OIL-NPs could reduce the pulmonary artery pressure of rats and alleviate the pathological injury and inflammatory reaction of heart and lung by inhibiting the PLC/IP3R/Ca2+ signal pathway.

Conclusion

OIL-NPs have anti-pulmonary hypertension effect, and the mechanism may be related to the inhibition of PLC/IP3R/Ca2+signal pathway.

OpiCa1-PEG-PLGA nanomicelles antagonize acute heart failure induced by the cocktail of epinephrine and caffeine

Background

Reducing Ca2+ content in the sarcoplasmic reticulum (SR) through ryanodine receptors (RyRs) by calcin is a potential intervention strategy for the SR Ca2+ overload triggered by β-adrenergic stress in acute heart diseases.

Methods

OpiCal-PEG-PLGA nanomicelles were prepared by thin film dispersion, of which the antagonistic effects were observed using an acute heart failure model induced by epinephrine and caffeine in mice. In addition, cardiac targeting, self-stability as well as biotoxicity were determined.

Results

The synthesized OpiCa1-PEG-PLGA nanomicelles were elliptical with a particle size of 72.26 nm, a PDI value of 0.3, and a molecular weight of 10.39 kDa. The nanomicelles showed a significant antagonistic effect with 100 % survival rate to the death induced by epinephrine and caffeine, which was supported by echocardiography with significantly recovered heart rate, ejection fraction and left ventricular fractional shortening rate. The FITC labeled nanomicelles had a strong membrance penetrating capacity within 2 h and cardiac targeting within 12 h that was further confirmed by immunohistochemistry with a self-prepared OpiCa1 polyclonal antibody. Meanwhile, the nanomicelles can keep better stability and dispersibility in vitro at 4 °C rather than 20 °C or 37 °C, while maintain a low but stable plasma OpiCa1 concentration in vivo within 72 h. Finally, no obvious biotoxicities were observed by CCK-8, flow cytometry, H&E staining and blood biochemical examinations.

Conclusion

Our study also provide a novel nanodelivery pathway for targeting RyRs and antagonizing the SR Ca2+ disordered heart diseases by actively releasing SR Ca2+ through RyRs with calcin.

Enhancing Anticancer Efficacy of Formononetin Microspheres via Microfluidic Fabrication

Formononetin is a flavonoid compound with anti-tumor and anti-inflammatory properties. However, its low solubility limits its clinical use. We employed microfluidic technology to prepare formononetin-loaded PLGA-PEGDA microspheres (Degradable polymer PLGA, Crosslinking agent PEGDA), which can encapsulate and release drugs in a controlled manner. We optimized and characterized the microspheres, and evaluated their antitumor effects. The microspheres had uniform size, high drug loading efficiency, high encapsulation efficiency, and stable release for 35 days. They also inhibited the proliferation, migration, and apoptosis. The antitumor mechanism involved the induction of reactive oxygen species and modulation of Bcl-2 family proteins. These findings suggested that formononetin-loaded PLGA-PEGDA microspheres, created using microfluidic technology, could be a novel drug delivery system that can overcome the limitations of formononetin and enhance its antitumor activity.

The Recent Applications of PLGA-Based Nanostructures for Ischemic Stroke

With the accelerated development of nanotechnology in recent years, nanomaterials have become increasingly prevalent in the medical field. The poly (lactic acid-glycolic acid) copolymer (PLGA) is one of the most commonly used biodegradable polymers. It is biocompatible and can be fabricated into various nanostructures, depending on requirements. Ischemic stroke is a common, disabling, and fatal illness that burdens society. There is a need for further improvement in the diagnosis and treatment of this disease. PLGA-based nanostructures can facilitate therapeutic compounds' passage through the physicochemical barrier. They further provide both sustained and controlled release of therapeutic compounds when loaded with drugs for the treatment of ischemic stroke. The clinical significance and potential of PLGA-based nanostructures can also be seen in their applications in cell transplantation and imaging diagnostics of ischemic stroke. This paper summarizes the synthesis and properties of PLGA and reviews in detail the recent applications of PLGA-based nanostructures for drug delivery, disease therapy, cell transplantation, and the imaging diagnosis of ischemic stroke.

Formulation of Resveratrol-Loaded Polycaprolactone Inhalable Microspheres Using Tween 80 as an Emulsifier: Factorial Design and Optimization

Resveratrol (RSV) is a bioactive phytoconstituent that has potential applications in respiratory diseases. However, poor oral bioavailability is the major hurdle to its clinical use. In the present work, resveratrol-loaded polycaprolactone (PCL) inhalable microspheres (MSs) were formulated to improve their therapeutic potential. The inhalable microspheres were formulated using the emulsion-solvent evaporation method. In this research, inhalable resveratrol microspheres were prepared using Tween 80 in place of polyvinyl alcohol which formed insoluble lumps. A 3² factorial design was applied taking polymer (PCL) and emulsifier (Tween 80) as independent variables and drug loading (DL) and encapsulation efficiency (EE) as dependent variables. The DL and EE of the optimized formulation were found to be 30.6% and 63.84% respectively. The in vitro aerosolization study performed using the Anderson cascade impactor showed that the fine particle fraction (FPF) of optimized resveratrol polycaprolactone microspheres (RSV-PCL-MSs) blended with lactose, and RSV-PCL-MSs were significantly higher than those of the pure drugs. The MMAD_T (theoretical mass median aerodynamic diameter) of optimized RSV-PCL-MSs was found to be 3.25 ± 1.15. The particle size of microspheres was within the inhalable range, i.e., between 1 and 5 µm. The morphological analysis showed spherical-shaped particles with smooth surfaces. The in vitro release study showed sustained drug release from the microspheres for up to 12 h. The study concluded that resveratrol-loaded inhalable microspheres may be an efficient delivery system to treat COPD.