Search Results (90)

Amphotericin B (AmB) is a broad-spectrum antifungal agent and a long-standing standard of care; however, its clinical use is compromised by poor solubility, off-target tissue distribution and severe dose-limiting toxicity. AmB-loaded poly (D, L-lactide-co-glycolide) nanoparticles (PLGA-AmB-NPs) were developed and characterized with respect to their physicochemical properties, antifungal activity against A. fumigatus biofilms, in vivo efficacy in the Galleria mellonella infection model, and hemolytic toxicity in vitro. Blank PLGA nanoparticles (PLGA-NPs) and PLGA-AmB-NPs exhibited mean diameters of 165 nm (PDI 0.075) and 120 nm (PDI 0.210), respectively, with negative zeta potential values consistent with colloidal stability in aqueous media. PLGA-AmB-NPs showed significantly enhanced activity against 24 h A. fumigatus biofilms compared with free AmB at concentrations of 5 and 10 µg/mL, while unloaded PLGA-NPs were inactive. Infected G. mellonella larvae treated with PLGA-AmB-NPs displayed markedly improved survival over a 5-day period relative to those receiving equivalent doses of free AmB. Furthermore, PLGA-AmB-NPs induced substantially lower hemolysis of human red blood cells than free AmB across all tested concentrations (5–20 µg/mL). PLGA-AmB-NPs represent a promising polymeric platform for the treatment of A. fumigatus infections. Full article

Alginate hydrogels offer mild ionic gelation and tunable porosity for drug delivery, yet their hydrophilic, macroporous networks suffer from rapid initial burst release of water-soluble payloads. Here we introduce a hierarchical barrier-engineering strategy in which poly(D,L-lactide-co-glycolide)/poly(ethylene glycol) (PLGA/PEG) blend coatings are applied via dip-coating to Ca²⁺-cross-linked alginate beads (~1 mm) and microgels (~100 µm). For beads, three-cycle PLGA/PEG multilayer coating suppressed the initial swelling rate (dQ/dt) by ~50% and reduced 1 h burst release from >85% to ~60%, functioning as an “early-burst buffer” rather than a long-term depot. For microgels, a single PLGA/PEG layer partially attenuated burst release; however, an additional PLGA outer shell (double-barrier architecture) shifted the release-governing mechanism from swelling-dominated to diffusion-barrier-dominated control, limiting 10 min release to <10%. Core–shell formation was verified by confocal laser scanning microscopy (CLSM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS); thermogravimetric analysis (TGA) showed ~73–79% coating retention after 9 days in phosphate-buffered saline (PBS, 37 °C). A vacuum re-loading process further improved encapsulation efficiency (>50% for beads, >20% for microgels) without compromising gel integrity. In beads, burst control was governed by swelling suppression; in microgels, the additional PLGA shell shifted control to diffusion-barrier-dominated release, demonstrating that barrier architecture must be adapted to particle scale. Full article

This study aims to assess the rate and duration of rat brain retention after a single intranasal administration of indocyanine green (ICG) as an aqueous solution or encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles. Near-infrared fluorescence emission of ICG from the brain and visceral organs was measured at 1, 4, and 24 h, as well as at 1 and 2 weeks after administration. It was observed that both ICG formulations stained the olfactory bulbs and brainstem, the latter mainly in the basolateral region of the pons. Reduced staining was observed on day 7 after treatment, and the signal remains detectable on day 14. Additionally, while emission from ICG-labeled brains in water decreased after two weeks compared to day 7, in ICG-loaded nanoparticles, the emission was significantly higher on day 14. It is concluded that ICG is transported into the brain via both nose-to-brain delivery pathways—through and along olfactory or trigeminal nerves—and that ICG is a useful dye for in vivo studies due to its long-lasting emission and low toxicity. Furthermore, the suggested penetration of ICG-encapsulated PLGA nanoparticles via these transport mechanisms makes them a useful carrier for brain delivery of substances that are rapidly eliminated from circulation or do not cross the blood–brain barrier. Full article

Background/Objectives. This research supports the development of long-acting injectables (LAIs) via in situ gel (ISG) technology by illustrating the influence of drug properties and formulation variables on in vitro drug release (Part 1), and providing an example of a point-to-point in vitro–in vivo correlation (IVIVC) for celecoxib ISGs (Part 2). Methods/Results. Part 1 evaluated the in vitro release (IVR) for ISGs containing 10 mg/g of five model drugs—paracetamol, theophylline, felbinac, indomethacin, and celecoxib—using two different poly(D,L-lactide-co-glycolide) (PLGA) grades with lactide/glycolide ratios (L/G) of 50:50 or 85:15 in N-methyl-2-pyrrolidone (NMP) at polymer/solvent ratios of 30/70% or 40/60% (w/w). The results demonstrated sustained IVR, with approximately 80% of the drug released within 1 to 5 days for the sparingly soluble compounds paracetamol and theophylline ISGs, and within 1.5 to 11 days, 3 to over 20 days, and 19 to 74 days for the slightly soluble compounds felbinac, indomethacin, and celecoxib, respectively. The IVR rate increased with decreasing polymer lipophilicity and concentration and with increasing drug solubility in the IVR medium. In Part 2, the pharmacokinetics of celecoxib ISGs were assessed following subcutaneous (SC) injection in rats. A point-to-point IVIVC was established between the fraction of drug absorbed derived via deconvolution (deconvoluted F_abs) and the fraction dissolved (observed F_diss) obtained in Part 1, based on Korsmeyer–Peppas fitting and release phase-specific scaling. Conclusions. In summary, this research highlights the significant impact of drug solubility, polymer grade, and concentration on the IVR rates of ISGs and provides an example of a point-to-point IVIVC for celecoxib ISGs with varying polymer concentrations and grades, following SC injection in rats. Full article

Background: Targeting cancer tumors using PLGA (Poly(D, L-lactide-co-glycolide)) nanoparticles (NPs) requires clathrin-mediated endocytosis (CME) and lysosomal degradation to provide release within cancer cells. However, Caveolae-mediated endocytosis (CavME) provides lysosomal escape, which is favorable in oral applications. Macropinocytosis (MPC) is a non-targeted way of endocytosis, used by immune cells. Methods: In this proof-of-concept study, we investigated how polysaccharide surface coatings modulate the endocytic uptake of FITC-labeled PLGA nanomicelles (FPM) in MCF-7 breast cancer cells using spectrophotometry. This research involved the surface modification of FPM using polysaccharides: cellulose (FPCM) as a polyglucan and Halomonas Levan (FPLM) as a polyfructan, to modify the NP and cell-surface association. Results: MPC was found to be the major internalization pathway for the nanomicelles ~200 nm. However, after surface modification, FPCM and FPM remained highly MPC-dependent with additional CavME/CME involvement, whereas FPLM showed relatively reduced MPC dependence and a higher CME contribution. Conclusion: Overall, the results indicate that simple polysaccharide coatings can bias the relative use of MPC, CME, and CavME for PLGA nanomicelles in MCF-7 cells, providing a basis for pathway-oriented nanocarrier design. Validation by flow cytometry, studies in additional breast cancer cell lines, and transporter-level investigations will be needed to generalize and refine these findings. Full article

Background/Objectives: Tuberculosis (TB) remains the leading cause of death from a single infectious agent worldwide. In line with the World Health Organization’s (WHO) goal to end TB by 2035, the rapid development and clinical implementation of new, effective vaccines is urgently needed. To support global TB control efforts, we developed a novel candidate subunit multistage vaccine. Methods: This vaccine incorporates multiple Mycobacterium tuberculosis antigens expressed during both dormant and active stages of infection, fused into a single recombinant protein (ESAT6-CFP10-Ag85A-Rv2660c-Rv1813c). The antigen was encapsulated in biodegradable poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles along with the pattern recognition receptor (PRR) agonists monophosphoryl lipid A (MPLA) and muramyl dipeptide (MDP), which function as adjuvants. Results: Using a mixed intramuscular/nasal prime-boost regimen, the vaccine elicited a mixed Th1/Th17 cell-mediated immune response, as well as a robust humoral response characterized by sustained systemic IgG (lasting at least one year) and prominent local secretory IgA. The vaccine demonstrated protective efficacy as a prophylactic booster following BCG priming in both murine and guinea pig models and was also effective in a therapeutic setting in a murine infection model. Conclusions: The results of this study provide empirical evidence that multistage tuberculosis vaccines represent a promising strategy for achieving global TB control. Full article

Poly(D,L-lactide-co-glycolide) (PLGA) has emerged as a cornerstone in the development of advanced drug delivery systems, particularly for intranasal and pulmonary routes. Its biodegradability, biocompatibility, and adaptability make it an ideal platform for addressing challenges associated with conventional therapies. By enabling sustained and controlled drug release, PLGA formulations reduce dosing frequency, improve patient compliance, and enhance therapeutic efficacy. These systems demonstrate versatility, accommodating hydrophilic and hydrophobic drugs, biological molecules, and co-delivery of synergistic agents. Moreover, surface modifications and advanced preparation techniques enhance targeting, bioavailability, and stability, expanding PLGA’s applications to treat complex diseases such as tuberculosis, cancer, pulmonary fibrosis, and CNS disorders. This manuscript provides an in-depth review of PLGA’s materials, properties, preparation methods, and therapeutic applications, alongside a critical evaluation of challenges and future opportunities in this field. Full article

Background/Objectives: The escalating challenge of antimicrobial resistance (AMR) necessitates the development of targeted antibiotic delivery platforms, minimising systemic administration. Polymer-based drug delivery emerges as a promising solution, ensuring sustained release and prolonged efficacy of bioactive compounds, ensuring long-term efficacy. Methods: This study focuses on encapsulating rifampicin (RIF), a key antibiotic for orthopaedic and wound-related infections, within Poly(d,l-lactide-co-glycolide) (PLGA), a biodegradable polymer, through solvent casting, to formulate a PLGA-RIF composite membrane. Comprehensive characterisation, employing Fourier-transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal analysis and X-ray Diffraction (XRD), confirmed the integrity of both the starting and produced materials. UV-Vis spectroscopy revealed a controlled drug release profile over 21 days in various media, with the chosen media influencing the drug release, notably the tryptic soya broth (TSB) caused the highest release. The quantitative assessment of the antimicrobial efficacy of the developed PLGA-RIF composite was conducted by measuring the size of the inhibition zones against both Gram-negative and Gram-positive bacteria. Results: The results confirmed the composite’s potential as a robust antibacterial biomaterial, demonstrating a rapid and effective antibacterial response. Cytocompatibility tests incorporated human fibroblast and osteoblast-like cell lines and demonstrated that the RIF:PLGA (1:8) formulation maintained eukaryotic cell viability, indicating the composite’s potential for targeted medical applications in combating bacterial infections with minimal systemic impact. Conclusions: This study presents the significance of investigating drug release within appropriate and relevant physiological media. A key novelty of this work therefore lies in the exploration of drug release dynamics across different media, allowing for a comprehensive understanding of how varying physiological conditions may influence drug release and its effect on biological responses. Full article

Haemonchus contortus is a gastrointestinal parasite that adversely impacts small ruminants, resulting in a notable reduction in animal productivity. In the current investigation, we developed a nanovaccine by encapsulating the recombinant protein rHcES-15, sourced from the excretory/secretory products of H. contortus, within biodegradable poly (D, L-lactide-co-glycolide) (PLGA) nanoparticles (NPs). The development of this nanovaccine involved the formulation of PLGA NPs using a modified double emulsion solvent evaporation technique. Scanning electron microscopy (SEM)verified the successful encapsulation of rHcES-15 within PLGA NPs, exhibiting a size range of 350–400 nm. The encapsulation efficiency (EE) of the antigen in the nanovaccine was determined to be 72%. A total of forty experimental mice were allocated into five groups, with the nanovaccine administered on day 0 and the mice euthanized at the end of the 14-day trial. The stimulation index (SI) from the mice subjected to the nanovaccine indicated heightened lymphocyte proliferation (*** p < 0.001) and a noteworthy increase in anti-inflammatory cytokines (IL-4, IL-10, and IL-17). Additionally, the percentages of T-cells (CD4⁺, CD8⁺) and dendritic cell phenotypes (CD83⁺, CD86⁺) were significantly elevated (** p < 0.01, *** p < 0.001) in mice inoculated with the nanovaccine compared to control groups and the rHcES-15 group. Correspondingly, higher levels of antigen-specific serum immunoglobulins (IgG1, IgG2a, IgM) were observed in response to the nanovaccine in comparison to both the antigenic (rHcES-15) and control groups (* p < 0.05, ** p < 0.01). In conclusion, the data strongly supports the proposal that the encapsulation of rHcES-15 within PLGA NPs effectively triggers immune cells in vivo, ultimately enhancing the antigen-specific adaptive immune responses against H. contortus. This finding underscores the promising potential of the nanovaccine, justifying further investigations to definitively ascertain its efficacy. Full article

Traumatic nerve defects result in dysfunctions of sensory and motor nerves and are usually accompanied by pain. Nerve guidance conduits (NGCs) are widely applied to bridge large-gap nerve defects. However, few NGCs can truly replace autologous nerve grafts to achieve comprehensive neural regeneration and function recovery. Herein, a three-dimensional (3D) sponge-filled nanofibrous NGC (sf@NGC) resembling the structure of native peripheral nerves was developed. The conduit was fabricated by electrospinning a poly(L-lactide-co-glycolide) (PLGA) membrane, whereas the intraluminal filler was obtained by freeze-drying a collagen-based matrix (ColM) resembling the extracellular matrix. The effects of the electrospinning process and of the composition of ColM on the physicochemical performance of sf@NGC were investigated in detail. Furthermore, the biocompatibility of the PLGA sheath and ColM were evaluated. The continuous and homogeneous PLGA nanofiber membrane had high porosity and tensile strength. ColM was shown to exhibit an ECM-like architecture characterized by a multistage pore structure and a high porosity level of over 70%. The PLGA sheath and ColM were shown to possess stagewise degradability and good biocompatibility. In conclusion, sf@NGC may have a favorable potential for the treatment of nerve reconstruction. Full article

Cardiovascular tissue engineering is providing many solutions to cardiovascular diseases. The complex disease demands necessitating tissue-engineered constructs with enhanced functionality. In this study, we are presenting the production of a dexamethasone (DEX)-loaded electrospun tubular polymeric poly(l-lactide) (PLA) or poly(d,l-lactide-co-glycolide) (PLGA) construct which contains iPSC-CMs (induced pluripotent stem cell cardiomyocytes), HUVSMCs (human umbilical vein smooth muscle cells), and HUVECs (human umbilical vein endothelial cells) embedded in fibrin gel. The electrospun tube diameter was calculated, as well as the DEX release for 50 days for 2 different DEX concentrations. Furthermore, we investigated the influence of the polymer composition and concentration on the function of the fibrin gels by imaging and quantification of CD31, alpha-smooth muscle actin (αSMA), collagen I (col I), sarcomeric alpha actinin (SAA), and Connexin 43 (Cx43). We evaluated the cytotoxicity and cell proliferation of HUVECs and HUVSMCs cultivated in PLA and PLGA polymeric sheets. The immunohistochemistry results showed efficient iPSC-CM marker expression, while the HUVEC toxicity was higher than the respective HUVSMC value. In total, our study emphasizes the combination of fibrin gel and electrospinning in a functionalized construct, which includes three cell types and provides useful insights of the DEX release and cytotoxicity in a tissue engineering perspective. Full article

Tendons are responsible for transmitting mechanical forces from muscles to bones for body locomotion and joint stability. However, tendons are frequently damaged with high mechanical forces. Various methods have been utilized for repairing damaged tendons, including sutures, soft tissue anchors, and biological grafts. However, tendons experience a higher rate of retear post-surgery due to their low cellularity and vascularity. Surgically sutured tendons are vulnerable to reinjury due to their inferior functionality when compared with native tendons. Surgical treatment using biological grafts also has complications such as joint stiffness, re-rupture, and donor-site morbidity. Therefore, current research is focused on developing novel materials that can facilitate the regeneration of tendons with histological and mechanical characteristics similar to those of intact tendons. With respect to the complications in association with the surgical treatment of tendon injuries, electrospinning may be an alternative for tendon tissue engineering. Electrospinning is an effective method for fabrication of polymeric fibers with diameters ranging from nanometers to micrometers. Thus, this method produces nanofibrous membranes with an extremely high surface area-to-volume ratio, which is similar to the extracellular matrix structure, making them suitable candidates for application in tissue engineering. Moreover, it is possible to fabricate nanofibers with specific orientations that are similar to those of the native tendon tissue using an adequate collector. To increase the hydrophilicity of the electrospun nanofibers, natural polymers in addition to synthetic polymers are used concurrently. Therefore, in this study, aligned nanofibers composed of poly-d,l-lactide-co-glycolide (PLGA) and small intestine submucosa (SIS) were fabricated using electrospinning with rotating mandrel. The diameter of aligned PLGA/SIS nanofibers was 568.44 ± 135.594 nm, which closely resembles that of native collagen fibrils. Compared to the results of the control group, the mechanical strength exhibited by the aligned nanofibers was anisotropic in terms of break strain, ultimate tensile strength, and elastic modulus. Elongated cellular behavior was observed in the aligned PLGA/SIS nanofibers using confocal laser scanning microscopy, indicating that the aligned nanofibers were highly effective with regard to tendon tissue engineering. In conclusion, considering its mechanical properties and cellular behavior, aligned PLGA/SIS is a promising candidate for tendon tissue engineering. Full article

Conjugated polymer nanoparticles (CPNs) are a promising class of nanomaterials for biomedical applications, such as bioimaging, gene and drug delivery/release, photodynamic therapy (PDT), photothermal therapy (PTT), and environmental sensing. Over the past decade, many reports have been published detailing their synthesis and their various potential applications, including some very comprehensive reviews of these topics. In contrast, there is a distinct lack of overview of the role the stabilizing copolymer shells have on the properties of CPNs. This review attempts to correct this oversight by scrutinizing reports detailing the synthesis and application of CPNs stabilized with some commonly-used copolymers, namely F127 (Pluronic poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) diacrylate), PSMA (poly(styrene-co-maleic anhydride)), PLGA (poly(D, L-lactide-co-glycolide)) and PEG (polyethylene glycol) derivatives. The analysis of the reported physicochemical properties and biological applications of these CPNs provides insights into the advantages of each group of copolymers for specific applications and offers a set of guidance criteria for the selection of an appropriate copolymer when designing CPNs-based probes. Finally, the challenges and outlooks in the field are highlighted. Full article

Respiratory syncytial virus (RSV) is one of the leading causes of bronchiolitis and pneumonia in children ages five years and below. Recent outbreaks of the virus have proven that RSV remains a severe burden on healthcare services. Thus, a vaccine for RSV is a need of the hour. Research on novel vaccine delivery systems for infectious diseases such as RSV can pave the road to more vaccine candidates. Among many novel vaccine delivery systems, a combined system with polymeric nanoparticles loaded in dissolving microneedles holds a lot of potential. In this study, the virus-like particles of the RSV fusion protein (F-VLP) were encapsulated in poly (D, L-lactide-co-glycolide) (PLGA) nanoparticles (NPs). These NPs were then loaded into dissolving microneedles (MNs) composed of hyaluronic acid and trehalose. To test the in vivo immunogenicity of the nanoparticle-loaded microneedles, Swiss Webster mice were immunized with the F-VLP NPs, both with and without adjuvant monophosphoryl lipid A (MPL) NPs loaded in the MN. The mice immunized with the F-VLP NP + MPL NP MN showed high immunoglobulin (IgG and IgG2a) levels both in the serum and lung homogenates. A subsequent analysis of lung homogenates post-RSV challenge revealed high IgA, indicating the generation of a mucosal immune response upon intradermal immunization. A flowcytometry analysis showed high CD8+ and CD4+ expression in the lymph nodes and spleens of the F-VLP NP + MPL NP MN-immunized mice. Thus, our vaccine elicited a robust humoral and cellular immune response in vivo. Therefore, PLGA nanoparticles loaded in dissolving microneedles could be a suitable novel delivery system for RSV vaccines. Full article

The use of intranasal implantable drug delivery systems has many potential advantages for the treatment of different diseases, as they can provide sustained drug delivery, improving patient compliance. We describe a novel proof-of-concept methodological study using intranasal implants with radiolabeled risperidone (RISP) as a model molecule. This novel approach could provide very valuable data for the design and optimization of intranasal implants for sustained drug delivery. RISP was radiolabeled with ¹²⁵I by solid supported direct halogen electrophilic substitution and added to a poly(lactide-co-glycolide) (PLGA; 75/25 _D,L-Lactide/glycolide ratio) solution that was casted on top of 3D-printed silicone molds adapted for intranasal administration to laboratory animals. Implants were intranasally administered to rats, and radiolabeled RISP release followed for 4 weeks by in vivo non-invasive quantitative microSPECT/CT imaging. Percentage release data were compared with in vitro ones using radiolabeled implants containing either ¹²⁵I-RISP or [¹²⁵I]INa and also by HPLC measurement of drug release. Implants remained in the nasal cavity for up to a month and were slowly and steadily dissolved. All methods showed a fast release of the lipophilic drug in the first days with a steadier increase to reach a plateau after approximately 5 days. The release of [¹²⁵I]I⁻ took place at a much slower rate. We herein demonstrate the feasibility of this experimental approach to obtain high-resolution, non-invasive quantitative images of the release of the radiolabeled drug, providing valuable information for improved pharmaceutical development of intranasal implants. Full article