Search Results (2,196)

Facial aging is not a singular phenomenon but a cascade of anatomical and biological transformations unfolding across the skeleton, fat, ligaments, muscles, dermis, and epidermis. Its clinical expression-volume loss, sagging, wrinkling, and surface irregularities-cannot be adequately explained by simplistic metaphors of “filling” or “lifting.” This article is a narrative review synthesizing current anatomical, physiological, and clinical evidence relevant to multimodal facial rejuvenation. Traditional monotherapies, while sometimes effective in isolation, are increasingly inadequate for contemporary patients who demand outcomes that are natural, harmonious, and durable. Modern esthetic practice has therefore shifted toward multimodal approaches that address aging across multiple planes. Hyaluronic acid (HA) fillers provide volumetric scaffolding and hydration; collagen stimulators such as poly-L-lactic acid (PLLA) and calcium hydroxylapatite (CaHA) induce neocollagenesis and long-term dermal remodeling; botulinum toxin restores balance to muscular vectors and improves expression dynamics; while energy-based devices (EBDs), including fractional lasers, radiofrequency microneedling, and high-intensity focused ultrasound (HIFU), enhance skin texture, tone, and elasticity. When applied in a sequenced and evidence-based manner, these modalities act synergistically to deliver results unattainable by any single intervention. In addition to established modalities, the field has recently witnessed aggressive promotion of “regenerative” therapies-growth factors, exosomes, platelet-rich plasma (PRP), and platelet-rich fibrin (PRF). While biologically plausible, their efficacy and safety remain uncertain due to the absence of robust, randomized clinical trials and the heterogeneity of current data. This raises a critical question: is aesthetic medicine advancing through science, or being driven by novelty and marketing? This review synthesizes current anatomical and physiological knowledge of aging, evaluates the mechanisms, clinical applications, and safety considerations of major treatment modalities, and proposes practical sequencing strategies. It also emphasizes the ethical imperative that aesthetic medicine, while innovative and fast-evolving, must remain anchored in scientific evidence and patient safety—because aesthetic medicine is, fundamentally, still medicine. Full article

Vanadium carbide (V₂C) MXene shows great potential for addressing challenging implant-associated infections in bone regeneration due to its strong photothermal conversion efficiency. However, its photothermal efficacy is restricted to the near-infrared I (NIR-I) region due to a limited absorption range. To address this, we designed platinum nanoparticle-decorated V₂C heterostructures (Pt@V₂C) via an in situ growth method, leveraging Pt’s plasmonic and catalytic properties to extend the photoresponse to the NIR-II window. Subsequently, Pt@V₂C was integrated into poly-L-lactic acid (PLLA) to fabricate PLLA-Pt@V₂C scaffolds with photothermal antibacterial function by selective laser sintering. The optimized PLLA-Pt@V₂C scaffold achieves a record photothermal conversion efficiency (56.03% at 1064 nm), triggering simultaneous hyperthermia (>52 °C) and catalytic ·OH radical generation. In vitro studies demonstrate exceptional antibacterial efficacy against Staphylococcus aureus and Escherichia coli, achieving over 99% killing rates upon 1064 nm near-infrared irradiation. Furthermore, the scaffold demonstrated significant inhibition of biofilm formation, achieving over 90% reduction in biofilm biomass. Moreover, the scaffold demonstrated high cell viability, confirming its dual functionality of potent bactericidal activity and biocompatibility that supports tissue regeneration. This work provides a feasible strategy for combating implant-associated infections. Full article

Background/Objectives: Poly(lactic-co-glycolic acid) (PLGA) microspheres offer sustained drug delivery but often suffer from broad particle size distribution (PSD), leading to inconsistent release profiles. This study investigates wet sieving as a post-processing strategy to precisely control PSD, quantified by the Span value, and evaluates its impact on the performance of triamcinolone acetonide (TA)-loaded PLGA microspheres. Methods: Triamcinolone acetonide-loaded PLGA microspheres were prepared via emulsification-solvent evaporation. Wet sieving was employed as a post-processing strategy to obtain distinct particle size fractions and groups with defined polydispersity (Span values). The microspheres were characterized for particle size distribution, drug loading, surface morphology, and in vitro release kinetics. To establish the in vivo relevance of polydispersity control, the pharmacokinetic profiles of different Span groups were first determined using LC-MS/MS following intra-articular injection in rats. Subsequently, their therapeutic efficacy was evaluated in a rat model of knee osteoarthritis, with outcomes assessed by joint swelling measurement and histopathological analysis. Results: Microspheres were prepared, fractionated into distinct size groups (0–20, 20–28, 28–40, 40–50, >50 μm) and polydispersity groups (Span = 1.4, 0.8, 0.5). We identified Span as a dominant factor independent of mean particle size. Reducing the Span from 1.4 to 0.5 significantly decreased burst release (24.15% to 14.51%), prolonged mean residence time (MRT 88.52 to 123.53 h), and enhanced anti-inflammatory and cartilage-protective effects in a rat model of knee osteoarthritis. Conclusions: This work establishes Span ≤ 0.5 as a critical quality attribute and presents wet sieving as a simple, effective method to ensure batch-to-batch consistency and predictable in vivo performance for PLGA microsphere products. Full article

Skin aging could lead to dermal collagen loss and elastic fiber degradation, ultimately manifesting as skin laxity. We aimed to counteract this by using poly-L-lactic acid (PLLA) microsphere (MS)-based fillers to facilitate long-term volume restoration through collagen regeneration. However, conventional MSs exhibit limitations such as broad size distribution and surface irregularities, which are frequently associated with significant adverse reactions. This study employed shirasu porous glass (SPG) membrane emulsification to fabricate uniform and well-shaped polyethylene glycol-block-poly (L-lactic acid) (PEG-PLLA) MSs. A single-factor experiment was employed to optimize the parameters. The optimal preparation conditions for PEG-PLLA MSs were as follows: PEG-PLLA concentration of 40 mg/mL, polyvinyl alcohol (PVA) concentration of 0.5%, and magnetic stirring speed of 200 rpm. Under the optimal conditions, the average particle size of PEG-PLLA MSs was 58.982 μm, and the span value (SPAN) was 1.367. In addition, a cytotoxicity assay was performed, and the results revealed no significant toxicity of the MSs toward L929 mouse fibroblasts at concentrations below 500 μg/mL. Furthermore, PEG-PLLA MSs significantly enhanced the production of key extracellular matrix (ECM) components—type I collagen (Col-I), type III collagen (Col-III), and hyaluronic acid (HA)—while simultaneously alleviating cellular oxidative stress responses. This work offers a reliable and reproducible fabrication strategy for developing biocompatible MS fillers with controllable particle sizes. Full article

Temporomandibular joint (TMJ) disorders represent chronic degenerative musculoskeletal conditions with a high prevalence in the general population and limited regenerative treatment options. Owing to the insufficient efficacy of current conservative and surgical therapies, there is a growing clinical need for biologically based regenerative approaches. Tissue engineering (TE), particularly scaffold-based strategies, has emerged as a promising avenue for TMJ regeneration. This systematic review analyzed preclinical in vivo studies investigating scaffold-based interventions for TMJ disc and osteochondral repair. A structured literature search of PubMed and Scopus databases identified 39 eligible studies. Extracted data included scaffold composition, use of cellular and bioactive components, animal models, and reported histological, radiological, and functional outcomes. Natural scaffolds, such as decellularized extracellular matrix and collagen-based hydrogels, demonstrated favorable biocompatibility and support for fibrocartilaginous regeneration, whereas synthetic materials including polycaprolactone, poly (lactic-co-glycolic acid), and polyvinyl alcohol provided superior mechanical stability and structural tunability. Cells were used in 17/39 studies (43%); quantitative improvements were variably reported across these studies. Bioactive molecule delivery, including transforming growth factor-β, histatin-1, and platelet-rich plasma, further enhanced tissue regeneration, while emerging drug- and gene-delivery approaches showed potential for modulating local inflammation. Despite encouraging results, the reviewed studies exhibited substantial heterogeneity in experimental design, outcome measures, and animal models, limiting direct comparison and translational interpretation. Scaffold-based approaches show preclinical promise but heterogeneity in design and incomplete quantitative reporting limit definitive conclusions. Future research should emphasize standardized methodologies, long-term functional evaluation, and the use of clinically relevant large-animal models to facilitate translation toward clinical application. However, functional and biomechanical outcomes were inconsistently reported and rarely standardized, preventing robust conclusions regarding the relationship between structural regeneration and restoration of TMJ function. Full article

The growing demand for sustainable materials and the valorization of waste streams have intensified research on wastewater biorefineries and bioplastics. Within this framework, this study aims to develop and characterize poly (lactic acid) (PLA)-based films partially substituted with microalgae biomass derived from wastewater treatment at different concentrations (PLA-MA: 0, 10, 20, 30, 40, and 50%). The films were produced and systematically characterized in terms of their morphological (SEM), structural (FTIR), physical (thickness, weight, swelling, and solubility), thermal (TGA), mechanical (tensile strength, elongation at break, and Young’s modulus), optical (colorimetry and UV–Vis), barrier (water vapor permeability), and biodegradability properties. FTIR analysis confirmed the successful incorporation of microalgae biomass into the polymeric matrix and indicated good compatibility at low biomass loadings, whereas higher concentrations (>20%) introduced hydrophilic functional groups associated with increasing structural incompatibility. Partial substitution of PLA with microalgae biomass significantly modulated the physical, mechanical, and optical properties of the resulting composites. Notably, biodegradability assays revealed that the PLA-MA 50% composite achieved 89% degradation within 120 days, demonstrating that microalgal biomass markedly accelerates material decomposition. Furthermore, antimicrobial tests conducted for PLA-MA 0%, 20%, and 50% confirmed the safety of wastewater-derived microalgae for incorporation into the polymer matrix. Overall, these results highlight the potential of wastewater-derived microalgae biomass as a promising and sustainable component for short-life-cycle bioplastic applications, particularly in the agricultural sector. Full article

Poly(lactic acid) (PLA)/starch composites have attracted considerable attention as promising eco-friendly materials due to their renewable origins and complementary properties. The system synergized benefits including cost reduction and enhancing biodegradation through filled with starch, and reducing moisture sensitivity by adding PLA. In recent years, PLA/starch composites have also emerged as functional materials for controlled-release applications, benefiting from their inherent phase-separated structures and distinct water solubility and degradation behaviors of the two components. By tailoring starch content and dispersion, starch-rich domains can serve as water-responsive pathways within the PLA matrix, enabling tunable release of functional substances from films or coatings. This concept has been successfully demonstrated in applications such as antimicrobial food packaging and slow-release fertilizer coatings. This review first outlines the fundamental aspects of PLA/starch composites, including microstructure, interfacial compatibility, and biodegradability. It then focuses on their design and performance as controlled-release systems, covering fabrication strategies, structure–property relationships, and evaluation methods. Finally, the advantages and limitations of current PLA/starch-based controlled-release materials are critically discussed, and future research directions are proposed to guide the development of sustainable, multifunctional materials for food packaging and agricultural applications. Full article

Poly(lactic acid) (PLA) is the most widely used feedstock in material extrusion (MEX) 3D printing. In this study, PLA was combined with 0–40 wt.% of poly(butylene adipate-co-terephtalate) (PBAT) to improve its ductility. The resulting blends were processed into filaments suitable for MEX 3D printing and used to fabricate specimens for mechanical characterization using three distinct raster angles (RAs; 0°, ±45°, and 90°) to statistically evaluate the individual and joint effects of blend composition and raster orientation. Melt flow index (MFI) measurements showed that increasing PBAT content reduced the MFI from 40.4 g/10 min to 34.4 g/10 min, which led to weaker bonding between printed beads, as shown in scanning electron microscopic images. Tensile strength, modulus, and impact strength were evaluated using tensile and Charpy tests. Statistical analysis showed that RA, PBAT concentration, and their interaction all significantly influenced (p < 0.05) mechanical performance. Both strength and modulus decreased as PBAT content and RA increased, with the highest values of 50 MPa and 2.78 GPa observed for neat PLA 3D-printed at 0° RA, and the lowest values of 15 MPa and 1.05 GPa for 40 wt.% PBAT at 90° RA. In contrast, incorporating PBAT improved impact strength, showing its toughening effect. Meanwhile, no clear trend between impact resistance and RA was observed. The highest impact strength (52.7 kJ/m²) was found at 40 wt.% PBAT content and ±45° RA. Full article

Lower respiratory tract infections caused by Pseudomonas aeruginosa are a global concern. Patients with chronic lung diseases such as cystic fibrosis and non-cystic fibrosis bronchiectasis often do not receive adequate antibiotic delivery through conventional routes. P. aeruginosa employs several mechanisms, including biofilm formation and efflux pumps to limit the accumulation of bactericidal drug concentrations. Direct drug delivery to the lung epithelial lining fluid can increase antibiotic concentration and reduce treatment failure rates. This review discusses current research and developments in inhaled antibiotic formulations for treating P. aeruginosa infections. Recent studies on particle engineering for the dry powder inhalers of antibiotics emphasized three fundamental principles of development: micro, nano, and nano-in-microparticles. Carrier-free microparticles showed potential for high-dose delivery but suffered from poor aerosolization, which could be improved through a drug–drug combination. Amino acids in a co-spray-dried system improved powders’ aerodynamics and reduced moisture sensitivity while incorporating the chitosan/poly(lactic-co-glycolic acid) (PLGA)-modified release of the drug. Nano-in-microsystems, embedding lipid carriers, showed improved antibiofilm activity and controlled release. We also highlight emerging biologics, including antibacterial proteins/peptides, vaccines, bacteriophages, and probiotics. Research on antibiotics and biologics for inhalation suggests excellent safety profiles and encouraging efficacy for some formulations, including antimicrobial peptides and bacteriophage formulations. Further research on novel molecules and synergistic biologic combinations, supported by comprehensive animal lung safety investigations, will be required in future developments. Full article

To construct a high-performance avermectin (Avm) carrier system, this study utilized the advantages of stereocomplex (SC) crystal formation between poly (L-lactic acid) (PLLA) and poly (D-lactic acid) (PDLA) to prepare Avm-loaded stereocomplex polylactic acid (SC-PLA) nanoformulations via the emulsion solvent evaporation method. The results showed the successful formation of SC-PLA after introducing PDLA into the PLLA matrix, and the influence of SC-PLA crystallinity enabled the fabrication of tunable Avm@SC-PLA nanospheres with a regular spherical morphology. Avm@SC-PLA exhibited controlled release characteristics and possessed pH-responsive properties with specific release behaviors under pH 5.5, 7.4, and 8.0 conditions. The Avm@SC-PLA sustained-release nano system had a series of advantages, including controllable particle size, efficient drug loading, excellent sustained-release performance, good UV-shielding ability, high stability, favorable spreadability, and strong affinity for different leaves. In conclusion, the Avm@SC-PLA nanoformulation not only achieves effective loading and stable encapsulation of Avm but also possesses good structural stability and environmental responsiveness. It provides a novel PLA-based carrier strategy for the efficient delivery of Avm and holds potential application value in the pesticide and pharmaceutical fields. Full article

Metformin is a promising small molecule for dentin regeneration, but an effective local delivery system for pulp applications has been underexplored. This study encapsulated metformin in poly(lactic-co-glycolic acid) (PLGA) microspheres and incorporated them into calcium phosphate–chitosan cement (CPCC) as a direct pulp-capping material (DPC). Metformin-PLGA microspheres were prepared by double emulsion and mixed with CPCC at a concentration of 0% to 20% by weight. Microsphere morphology, encapsulation efficiency, chemical composition, and physico-mechanical properties were characterized, and compatibility with human dental pulp stem cells (hDPSCs) was evaluated by live/dead assay and SEM. The microspheres were spherical (5.43 ± 0.17 µm) with (51 ± 3.69%) encapsulation efficiency, and FTIR confirmed metformin incorporation. The 15% Met-PLGA-CPCC group showed flexural strength (15.22 ± 1.98 MPa), elastic modulus (4.60 ± 0.73 GPa), and work of fracture (104.96 ± 12.48 J/m²) comparable to or higher than CPCC and MTA, while all Met-PLGA-CPCC groups had shorter setting times ranging from 18 min to 27 min than CPCC (39.15 ± 2.10 min) and MTA (123 ± 4.2 min). Metformin release increased proportionally with Met-PLGA content. hDPSCs exhibited good attachment and high viability on all materials over the evaluated period. In conclusion, Met-PLGA-CPCC provides fast-setting and favorable physico-mechanical properties, sustained metformin delivery, and excellent hDPSC compatibility. These properties support its potential as a bioactive direct pulp-capping material and as a versatile platform for regenerative applications. Full article

Polylactic acid (PLA) is a promising biodegradable polymer whose widespread application is hindered by inherent brittleness. Polyethylene glycol (PEG) is a common plasticizer, but the effects of intermediate molecular weights, such as 4000 g/mol, on the coupled thermal, mechanical, and rheological properties of PLA remain insufficiently understood. This study presents a comprehensive analysis of PLA plasticized with 0–20 wt% PEG 4000, employing differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and rheology. DSC confirmed excellent miscibility and a significant glass transition temperature (T_g) depression exceeding 19 °C for the highest concentration. A complex, non-monotonic evolution of crystallinity was observed, associated with the formation of different crystalline forms (α′ and α). Critically, DMA revealed that the material’s thermo-mechanical response is dominated by its thermal history: while the plasticizing effect is masked in highly crystalline, as-cast films, it is unequivocally demonstrated in quenched amorphous samples. The core finding emerges from a targeted rheological investigation. An anomalous increase in melt viscosity and elasticity at intermediate PEG concentrations (5–15 wt%), observed at 180 °C, was systematically shown to vanish at 190 °C and in amorphous samples. This proves that the anomaly stems from residual crystalline domains (α′ precursors) persisting near the melting point, not from a transient molecular network. These results establish that PEG 4000 is a highly effective PLA plasticizer whose impact is profoundly mediated by processing-induced crystallinity. This work provides essential guidelines for tailoring PLA properties by controlling thermal history to optimize flexibility and processability for advanced applications, specifically in melt-processing for flexible packaging. Full article

The present study reports the design and physicochemical characterization of a hybrid nanoparticle system for the potential intranasal delivery of galantamine (GAL), aimed at improving its bioavailability. Carbon dots (CDs) were used to load GAL, enhancing its dissolution and stability, and were subsequently incorporated into a poly(lactic-co-glycolic acid)–curcumin (PLGA–Cur) conjugate matrix. The successful formation of the PLGA-Cur conjugate was verified via ¹H-NMR and FTIR spectroscopy, while the loading of GAL and its physical state in the CDs was assessed via FTIR and pXRD, respectively. The resulting GAL-CD/PLGA–Cur nanoparticles were spherical, with particle sizes varying from 153.7 nm to 256.3 nm, a uniform morphology and a narrow size distribution. In vitro release studies demonstrated a multi-phase sustained release pattern extending up to 12 days. Spectroscopic and thermal analyses confirmed successful conjugation and molecular interactions between GAL and the carrier matrix. This proof-of-concept hybrid system demonstrates promising controlled, multi-phase sustained galantamine release in vitro, highlighting the role of curcumin conjugation in modulating polymer structure and release kinetics and providing a foundation for future biological evaluation. Full article

Spinal cord injury (SCI) remains a major clinical challenge due to the limited regenerative capacity of the central nervous system (CNS). Effective scaffolds for repair must combine mechanical compatibility with host tissue, controlled degradation matching the time course of regeneration, and microarchitectural features that promote neuronal survival. Electrospun nanofibrous scaffolds mimic the structural and mechanical features of the extracellular matrix, providing critical cues for neuronal adhesion and glial modulation in neural regeneration. Here, we fabricated biodegradable poly(lactic acid)/poly(ε-caprolactone) (PLA/PCL) scaffolds using a dichloromethane/tetrahydrofuran (DCM/THF) solvent system to induce surface porosity via solvent-driven phase separation. The DCM/THF solvent system formulation produced nanofibers with porous surfaces and increased area for cell interaction. PLA/PCL scaffolds showed a Young’s modulus of ~26 MPa and sustained degradation, particularly under oxidative conditions simulating the post-injury microenvironment. In vitro, these scaffolds enhanced neuronal density up to fivefold and maintained ~80% viability over 10 days in primary neuron–glia cultures. Morphometric analysis revealed that DCM/THF-based scaffolds supported astrocytes with preserved process complexity and reduced circularity, indicative of a less reactive morphology. In contrast, scaffolds fabricated with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) displayed reduced bioactivity and promoted morphological features associated with astrocyte reactivity, including cell rounding and process retraction. These findings demonstrate that solvent-driven control of scaffold microarchitecture is a powerful strategy to enhance neuronal integration and modulate glial morphology, positioning DCM/THF-processed PLA/PCL scaffolds as a promising platform for CNS tissue engineering. Full article

Tympanic membrane (TM) perforations, arising from infections, injuries, or chronic otitis media, remain a frequent clinical finding and can lead to hearing problems when the tissue does not regenerate adequately. Although autologous grafts are still the standard option for repairing persistent defects, they come with well-known limitations. Beyond the need for additional harvesting procedures, these grafts rarely reproduce the intricate, fibrous layering of the native TM, which can compromise sound transmission after healing. In search of alternatives, fibre-based scaffolds have attracted considerable interest. The primary advantage of this material is the level of structural control it affords. The fibre orientation, porosity, and overall microarchitecture can be adjusted to replicate the organisation and mechanical behaviour of the natural membrane. A range of biocompatible polymers—among them silk fibroin, poly(ε-caprolactone), poly(lactic acid), and poly(vinyl alcohol) and their composites—provide options for tuning stiffness, degradation rates, and interactions with cells, making them suitable building blocks for TM repair constructs. This review provides a comprehensive overview of contemporary fabrication methodologies, namely electrospinning, additive manufacturing, melt electrowriting, and hybrid strategies. In addition, it offers a detailed discussion of the evaluation procedures employed for these scaffolds and discusses how scaffold structure affects later performance. Mechanical testing, microstructural imaging, and in vitro biocompatibility assays help to determine how closely a construct can approach the performance of the native tissue. Bringing these elements together may support the gradual translation of fibre-based TM scaffolds into clinical practice. Full article