Poly L-lactic Acid Research Articles

MXene-coated piezoelectric poly-L-lactic acid membrane accelerates wound healing by biomimicking low-voltage electrical pulses

Electrical stimulation therapy is effective in promoting wound healing by rescuing the decreased endogenous electrical field, where self-powered and miniaturized devices such as nanogenerators become the emerging trends. While high-voltage and unidirectional electric field may pose thermal effect and damage to the skin, nanogenerators with lower voltages, pulsed or bidirectional currents, and less invasive electrodes are preferred. Herein, we construct a polydopamine (PDA)-modified poly-L-lactic acid (PLLA) /MXene (PDMP/MXene) nanofibrous composite membrane that generates piezoelectric voltages matching the transepithelial potential (TEP) to accelerate wound healing. PDA coating not only enhances the piezoelectricity of PLLA by dipole attraction and alignment, but also increases its hydrophilicity and facilitates subsequent MXene adhesion for electrical conductivity and stability in physiological environment. When applied as wound dressings in mice, the PDMP/MXene membranes act as a nanogenerators with reduced internal resistances and satisfactory piezoelectric performances that resemble bioelectric potentials (~10 mV) responding to physical activities. The membrane significantly accelerates wound closure by facilitating fibroblast migration, collagen deposition and angiogenesis, and suppressing the expression of inflammatory responses. This piezoelectric fibrous membrane therefore provides a convenient solution for speeding up wound healing by sustained low voltage mimicking bioelectricity, better cell affinity.

Melatonin-coated nanofiber cell sheets promote periodontal regeneration through ROS scavenging and preservation of stemness

Mesenchymal stem cell (MSC)-based cell sheet engineering holds great promise for periodontal tissue engineering and restoring damaged tissues. However, achieving optimal regenerative outcomes remains a challenge. This study introduces a novel approach that integrates melatonin-coated nanofiber fragments (mNFs) into dental follicle stem cell sheets (mNF-CSs) to enhance their regenerative potential. The mNF-CSs were engineered using electrospun poly-L-lactic acid (PLLA) nanofiber sheets fragmented into mNFs and coated with melatonin, a potent antioxidant and osteogenic agent. The mNF-CSs exhibited a homogenous morphology with sustained melatonin release over 21 days, providing a prolonged antioxidative effect critical for tissue regeneration. In vitro experiments demonstrated that mNF-CSs significantly reduced intracellular reactive oxygen species (ROS) levels and upregulated antioxidative proteins such as SOD1 and SOD2, resulting in improved cell viability, maintenance of stemness, and enhanced osteogenic differentiation potential of dental follicle stem cells (DFCs). In vivo studies using both a nude mouse and a rat periodontal defect model demonstrated that mNF-CSs promoted alveolar bone repair and periodontal tissue regeneration, with enhanced retention of MSCs at the defect site and increased expression of periodontal tissue-related markers. Transcriptome analysis revealed the upregulation of genes associated with biomineralization, odontogenesis, and autophagy pathways in mNF-CSs, suggesting their ability to modulate crucial cellular processes for tissue regeneration. Overall, mNF-CSs offer a promising strategy for enhancing periodontal tissue engineering applications, providing a platform for improving bone grafts and regenerative medicine strategies in the context of periodontal diseases.

Piezoelectric Biomedical Material, Poly-L-Lactic Acid (PLLA), in the Treatment of Spinal Epidural Compression: Diagnosis, Monitoring, and Postoperative Support

This study aims to design an intelligent biomedical piezoelectric material for monitoring the pressure in the spinal epidural space caused by postoperative hematoma compression (spinal epidural hematoma). Hematoma compression in the spinal epidural space is a clinically challenging condition that is difficult to diagnose, and failure to address it within forty-eight hours may lead to severe consequences. Given its urgency, prompt and accurate diagnosis and intervention are crucial. Due to its elusive diagnostic nature, patients often miss the opportune time for treatment. Therefore, this study utilizes poly L-lactic acid (PLLA), an FDA-approved highly biocompatible biomaterial. After undergoing high-pressure polarization, PLLA exhibits excellent piezoelectric properties, making it an ideal material for monitoring intracavitary pressure. Additionally, since postoperative hematoma formation is a primary cause of spinal epidural membrane compression, this study integrates urokinase, a potent thrombolytic protein, with PLLA electrospun fibers, enabling preliminary treatment upon pressure detection.This intelligent organic biomedical material not only enables real-time monitoring of postoperative spinal epidural space pressure but also passively utilizes ultrasound to release urokinase from PLLA fibers for initial treatment when pressure is detected. Furthermore, the application of electrospun PLLA biomedical material makes the material more easily moldable and simplifies the manufacturing process, expanding its potential applications. In summary, this technology combines expertise in organic materials science, electrochemistry, and clinical medicine, offering an innovative approach to addressing the crisis posed by hematoma compression in the spinal epidural space. In future clinical applications, this technology holds the promise of providing earlier and more effective treatment for patients, potentially becoming a significant breakthrough in the fields of medical electronics and biomedical engineering. Keywords: Piezoelectric Biomaterial, Pressure Monitoring Sensor, Drug Control Release, Postoperative Support, Diagnostic Innovation

An In Vitro Model of the Blood-Brain Barrier for the Investigation and Isolation of the Key Drivers of Barriergenesis.

The blood-brain barrier (BBB) tightly regulates substance transport between the bloodstream and the brain. Models for the study of the physiological processes affecting the BBB, as well as predicting the permeability of therapeutic substances for neurological and neurovascular pathologies, are highly desirable. Existing models, such as Transwell utilizing-models, do not mimic the extracellular environment of the BBB with their stiff, semipermeable, non-biodegradable membranes. To help overcome this, we engineered electrospun membranes from poly L-lactic acid in combination with a nanometric coating of poly(ethyl acrylate) (PEA) that drives fibrillogenesis of fibronectin, facilitating the synergistic presentation of both growth factors and integrin binding sites. Compared to commercial semi-porous membranes, these membranes significantly improve the expression of BBB-related proteins in brain endothelial cells. PEA-coated membranes in combination with different growth factors and extracellular protein coatings reveal nerve growth factor (NGF) and fibroblast growth factor (FGF-2) caused formation of better barriers in vitro. This BBB model offers a robust platform for studying key biochemical factors influencing barrier formation that marries the simplicity of the Transwell model with the highly tunable electrospun PEA-fibronectin membranes. This enables the generation of high-throughput drug permeability models without the need of complicated co-culture conditions.

Lactate triggers KAT8-mediated LTBP1 lactylation at lysine 752 to promote skin rejuvenation by inducing collagen synthesis in fibroblasts

Decreased collagen synthesis by fibroblasts is a key aspect of skin aging. Poly-L-Lactic Acid (PLLA) is a bioabsorbable material that can release lactate continuously, stimulating endogenous collagen synthesis in the skin. Herein, this study aimed to investigate the impact of PLLA-released lactate on collagen production in fibroblasts for skin rejuvenation. Human fibroblasts were exposed to varying concentrations of PLLA in vitro, while PLLA was injected into the back skin of aged mice in vivo. Safety and efficacy of PLLA on collagen synthesis and skin rejuvenation were evaluated through Calcein-AM/PI staining, EdU proliferation assay, and analysis of collagen I and collagen III expression in fibroblasts using western blotting and immunofluorescence. To elucidate the underlying mechanisms, lactate contents in cell-free supernatant and cell lysates from PLLA-treated fibroblasts, as well as total lysine lactylation (Pan Kla) levels were measured. Additionally, we found that fibroblasts can uptake extracellular lactate released from PLLA through monocarboxylate transporter-1 (MCT1) to facilitate latent-transforming growth factor beta-binding protein 1 (LTBP1) lactylation at lysine 752 (K752) via a KAT8-dependent mechanism, then increases the protein levels of collagen I and collagen III in fibroblasts. Overall, this study highlights a valuable insight into lactylation modification of non-histone protein for skin rejuvenation.

Polydopamine-modified biochar supported polylactic acid and zero-valent iron affects the functional microbial community structure for 1,1,1-trichloroethane removal in simulated groundwater

In-situ enhanced bioreduction by functional materials is a cost-effective technology to remove chlorinated hydrocarbons in groundwater. Herein, a novel polydopamine (PDA)-modified biochar (BC)-based composite containing nanoscale zero-valent iron (nZVI) and poly-l-lactic acid (PLLA) (PB-PDA-Fe) was synthesized to enhance the removal of 1,1,1-trichloroethane (1,1,1-TCA) in simulated groundwater with actual site sediments. Its impact on functional microbial community structure in system was also investigated. The typical characterizations revealed uniform dispersion of PLA and nZVI particles on the BC surface, being smoother after PDA coating. The composite exhibited a significantly higher performance on 1,1,1-TCA removal (82.38%, initial concentration 100 mg/L) than Fe-PDA and PB-PDA treatments. The diversity and richness of the microbial community in the composite treatment consistently decreased during incubation due to a synergistic effect between PLLA-BC and nZVI. Desulfitobaterium, Pedobacter, Sphaerochaeta, Shewanella, and Clostridium were identified as enriched genera by the composite through DNA-stable isotope probing (DNA-SIP), playing a crucial role in the bioreductive dechlorination process. All the above results demonstrate that this novel composite selectively enhances the activity of microorganisms with extracellular respiration functions to efficiently dechlorinate 1,1,1-TCA. These findings could contribute to understanding the responsive microbial community by carbon-iron composites and expedite the application of in-situ enhanced bioreduction for effective remediation of chlorinated hydrocarbon-contaminated groundwater.

Comparative Rheology of Hyaluronic Acid Fillers, Poly-l-lactic Acid, and Varying Dilutions of Calcium Hydroxylapatite.

This study examines the rheological properties of various dermal fillers, including hyaluronic acid (HA) fillers, poly-L-lactic acid (PLLA), and calcium hydroxylapatite-carboxymethylcellulose (CaHA-CMC) gels, with a particular focus on the impact of aqueous dilution on CaHA-CMC's rheology and potential clinical implications. Using standardized rheological analysis, we measured and compared the elastic modulus (G'), viscous modulus (G″), and the tan δ values of different dilutions of CaHA-CMC against published values of HA and PLLA fillers. The study aimed to determine the potential clinical use of application-specific CaHA-CMC hydrogel dilutions along a range of gel strength and cohesion for hydrogel fillers in current use. The findings demonstrate that CaHA-CMC's rheological properties can be tailored across a broad spectrum of viscoelastic parameters through titrated dilution, ranging from high elasticity to low cohesion. Varying the aqueous volume allows for the rheomodulation of CaHA-CMC, potentially matching the entire rheological spectrum of HA fillers and suggesting an expanded range of clinical applications. The versatility of CaHA-CMC through dilution may offer a customizable approach for clinical applications, providing practitioners with the ability to fine-tune the properties of fillers to meet specific patient needs and treatment goals. This study lays the groundwork for the potential future use of filler dilutional rheomodulation in clinical practice, tailored to patient- and application-specific needs.

Targeted and Therapeutic Efficacy of 5-Fluorouracil-Loaded Polylactic Acid Nanocomplexes in Gastric Cancer

Gastric cancer (GC), arising from gastric mucosal cells, necessitates innovative treatment strategies beyond conventional surgical approaches. While 5-fluorouracil (5-FU) has demonstrated efficacy in various cancers, its lack of selectivity for cancer cells and limited half-life pose challenges. This study focuses on assessing the therapeutic potential of 5-FU-loaded L-polylactic acid (PLLA) nanofibers (NFs) for targeted GC treatment. The preparation of 5-FU/PLLA NFs involved refining the drug delivery approach to enhance drug impact on GC cell proliferation and apoptosis. Utilizing an organic phase separation methodology, 5-FU was incorporated into PLLA NFs, and the NF morphology was examined using scanning electron microscopy, with optical microscopy used for diameter measurement. Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) explored binding state and PLLA crystallinity. Drug loading (DL) capacity and in vitro release characteristics were evaluated by UV-visible spectrophotometry, while NF degradation and stability were assessed. The human gastric adenocarcinoma (AGS) cell line was employed in cell experiments, with three groups: normal culture (Normal group), single drug treatment with 5-FU (5 μmol/L, 5-FU group), and 5-FU-loaded PLLA group (5-FU/PLLA group) containing 5 μmol/L 5-FU. Cell Counting Kit-8 gauged cell proliferation and viability, and Annexin V-FITC/PI assay determined cell apoptosis. Results revealed a (1,230.8±18.9) nm diameter for 5-FU/PLLA NFs with 18.3% crystallinity. FTIR and DSC analyses indicated a simple physical mixture of 5-FU and PLLA in 5-FU/PLLA. DL capacity was (18.1±2.3)%, with a DL efficiency of (92.5±9.4)%. in vitro release performance of 5-FU/PLLA surpassed that of raw 5-FU. The mass loss rate of 5-FU/PLLA was consistent across different pH buffer solutions, with a stable drug release (DR) rate over various storage times. In cell experiments, both 5-FU and 5-FU/PLLA groups exhibited reduced proliferation and viability compared to the Normal group, with higher apoptosis rates (P < 0.05). Furthermore, the 5-FU/PLLA group showed decreased proliferation and viability compared to the 5-FU group, accompanied by higher apoptosis rates (P < 0.05). In conclusion, 5-FU-loaded PLLA NFs, with excellent DR properties, demonstrated significant inhibitory and cytotoxic effects on GC cells.

Poly-L-Lactic Acid Reduces the Volume of Dermal Adipose Tissue Through its Metabolite Lactate.

Poly-L-lactic acid (PLLA), a well-established biostimulator that induces collagenases, is widely used among clinical practice to treat skin aging. However, the precise regulatory effect of PLLA on different dermal cell subsets beyond fibroblast has not been fully elucidated. In this study, we constructed in vivo PLLA injection and in vitro PLLA-adipocyte co-culture models to analyze the regulatory effects of PLLA on the volume, differentiation, lipolysis, and thermogenic capacity of dermal adipocyte. We found that PLLA injection significantly reduced the thickness of dermal fat in mice. In co-culture assay, PLLA showed no effect on adipogenesis, but stimulated the lipolysis activity. Interestingly, PLLA also enhanced the differentiation of fat cells into beige fat cells, which possess higher thermogenic capacity. In mechanical study, we blocked adipocyte lactate uptake with a monocarboxylate transporter (MCT1/4) inhibitor and found that the regulatory effect of PLLA on dermal adipocyte relies on its metabolite lactate. In summary, our results suggest that PLLA has complex regulatory effects on the dermal cells, and its ability to improve skin aging is not fully attributed to stimulating collagen synthesis, but also partially involves adipocytes.No Level Assigned This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Employing novel biocompatible composite scaffolds with bioglass 58S and poly L-lactic acid for effective bone defect treatment.

Bioglass materials have gained significant attention in the field of tissue engineering due to their osteoinductive and biocompatible properties that promote bone cell differentiation. In this study, a novel composite scaffold was developed using a sol-gel technique to combine bioglass (BG) 58S with a poly L-lactic acid (PLLA). The physiochemical properties, morphology, and osteoinductive potential of the scaffolds were investigated by X-ray diffraction analysis, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The results showed that the SiO2-CaO-P2O5 system was successfully synthesized by the sol-gel method. The PLLA scaffolds containing BG was found to be osteoinductive and promoted mineralization, as demonstrated by calcium deposition assay, upregulation of alkaline phosphatase enzyme activity, and Alizarin red staining data. These in vitro studies suggest that composite scaffolds incorporating hBMSCs are a promising substitute material to be implemented in bone tissue engineering. The PLLA/BG scaffolds promote osteogenesis and support the differentiation of bone cells, such as osteoblasts, due to their osteoinductive properties.

Trimethylsilane Plasma-Nanocoated Silver Nanowires for Improved Stability.

The objective of this study was to evaluate the effectiveness of trimethylsilane (TMS) plasma nanocoatings in protecting silver nanowires (AgNWs) from degradation and thus to improve their stability. TMS plasma nanocoatings at various thicknesses were deposited onto AgNWs that were prepared on three different substrates, including glass, porous styrene-ethylene-butadiene-styrene (SEBS), and poly-L-lactic acid (PLLA). The experimental results showed that the application of TMS plasma nanocoatings to AgNWs induced little increase, up to ~25%, in their electrical resistance but effectively protected them from degradation. Over a two-month storage period in summer (20-22 °C, 55-70% RH), the resistance of the coated AgNWs on SEBS increased by only ~90%, compared to a substantial increase of ~700% for the uncoated AgNWs. On glass, the resistance of the coated AgNWs increased by ~30%, versus ~190% for the uncoated ones. When stored in a 37 °C phosphate-buffered saline (PBS) solution for 2 months, the resistance of the coated AgNWs on glass increased by ~130%, while the uncoated AgNWs saw a ~970% rise. Increasing the TMS plasma nanocoating thickness further improved the conductivity stability of the AgNWs. The nanocoatings also transformed the AgNWs' surfaces from hydrophilic to hydrophobic without significantly affecting their optical transparency. These findings demonstrate the potential of TMS plasma nanocoatings in protecting AgNWs from environmental and aqueous degradation, preserving their electrical conductivity and suitability for use in transparent electrodes and wearable electronics.

Clinical applications of a novel poly-L-lactic acid microsphere and hyaluronic acid suspension for facial depression filling and rejuvenation.

Poly L-lactic acid (PLLA) can stimulate fibrous tissue regeneration to exert a filling effect. However, severe inflammatory reactions and unsatisfactory effects remain a concern. Herein, we describe the mechanism of action, efficacy, and safety of PLLA microspheres in suspension (PLLA-b-PEG/HA) for facial contouring and soft tissue augmentation. PLLA-b-PEG/HA, ssynthesized by copolymerization with ethylene glycol, were suspended in hyaluronic acid (HA). Physiological verification was performed using scanning electron microscopy and X-ray computed tomography. PLLA-b-PEG/HA were subcutaneously injected into the dorsal region of 4-month-old rabbits. Ultrasound assessed volumetric capacity at 3 days and 1, 2, 4, and 12 weeks. The inflammatory response, collagen production, and HA degradation were evaluated. A retrospective case series of 10 patients who received PLLA-b-PEG/HA injections was conducted to assess long-term efficacy and safety. PLLA-b-PEG exhibited a spherical structure with a smooth surface (20-45 μm diameter). In rabbits, implant site volume increased within 4 weeks, gradually decreasing thereafter. Fibrous capsules, microvessel density, and new collagen fiber formation progressively increased at 4, 12, and 26 weeks after injection. Clinical data demonstrated significant improvements in face contouring at months 3 and 12 after injection. All patients showed improved internal contours based on the Global Aesthetic Improvement Scale. After 12 months, 90% of the patients retained good shaping and support effects with minimal adverse reactions. PLLA-b-PEG/HA demonstrated superior biocompatibility and facial regeneration potential, with outstanding dual collagen-stimulating properties. The clinical efficacy and safety of PLLA-b-PEG/HA have been validated and established as a promising therapeutic option.

Cross-linked Sodium Hyaluronate Gel with PLLA-b-PEG Microsphere for Facial Contouring in Chinese: A Retrospective Study.

In Asia, the demand for cosmetic facial treatments has surged due to technological advancements, increased social acceptability, and affordability. Poly-L-lactic acid (PLLA) fillers, known for their biocompatibility and biodegradability, have emerged as a popular choice for facial contouring, yet studies specifically addressing their use in Asian populations are scarce. This retrospective study examined 30 Chinese patients who underwent facial contouring with PLLA fillers, focusing on product composition, injection techniques, and safety measures. A comprehensive clinical evaluation was performed, including the Global Aesthetic Improvement Scale (GAIS) and Global Impression of Change Scale (GICS) for effectiveness and patient satisfaction, respectively. No significant difference in GAIS scores was observed between injectors and blinded evaluators over a 12-month period, indicating consistent effectiveness. Patient satisfaction remained high, with GICS scores reflecting positive outcomes. The safety profile was favorable, with no serious adverse events reported. The study highlighted the importance of anatomical knowledge to avoid complications, particularly in areas prone to blindness. PLLA fillers offer a safe, effective option for facial contour correction in the Asian population, achieving high patient satisfaction and maintaining results over time. The study underscores the need for tailored approaches in cosmetic procedures for Asians, considering their unique facial structures and aesthetic goals. Further research with larger, multicenter cohorts is recommended to validate these findings and explore long-term effects. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparison of the effect of oxygen and nitrogen plasma treatments on the surface activation of PLA/rGO composites

Cold plasma is known as a method to enhance the adsorption of proteins on the surface of biomaterials. In this experimental study, the efficacy of oxygen and nitrogen plasma treatment on the activation of Poly l-lactic acid/reduced graphene oxide composite (PLAG) was investigated. For this purpose, the chemical, physicochemical, and morphological characteristics, ability to adsorb amino acid l-tyrosine, and biological behavior of the oxygen and nitrogen plasma-treated composites (PLAG-O and PLAG-N) were studied. Following the exposure to oxygen and nitrogen plasma, (PLAG-O) composites presented more enhancement in Raman CC and CH bonds. The evaluation of l-tyrosine adsorption revealed the higher intensity of FTIR CN, CC and NH and Raman CH chemical bonds and also lower intensity of l-tyrosine UV absorbance in solution medium for l-tyrosine-adsorbed oxygen plasma-treated (PLAG-Ot) compared to l-tyrosine-adsorbed nitrogen plasma-treated (PLAG-Nt) composites. More apparent l-tyrosine island-shaped zones were appeared all over the surface of PLAG-Ot composites through FE-SEM experiment. Moreover, conducting detailed AFM study revealed a higher difference in surface roughness (Ra) of the PLAG-O and PLAG-Ot (140 nm) compared to the PLAG-N and PLAG-Nt composites (25 nm). From the biological point of view, the oxygen plasma-treated composites presented better HDF cell behavior in terms of viability and attachment, as well. According to the results of this study, the oxygen plasma treatment exhibits a higher potential to activate Poly l-lactic acid–reduced graphene oxide composite surface compared to the surface treatment in nitrogen plasma.

Piezo1 Activation Drives Enhanced Collagen Synthesis in Aged Animal Skin Induced by Poly L-Lactic Acid Fillers.

Poly L-lactic acid (PLLA) fillers stimulate collagen synthesis by activating various immune cells and fibroblasts. Piezo1, an ion channel, responds to mechanical stimuli, including changes in extracellular matrix stiffness, by mediating Ca2+ influx. Given that elevated intracellular Ca2+ levels trigger signaling pathways associated with fibroblast proliferation, Piezo1 is a pivotal regulator of collagen synthesis and tissue fibrosis. The aim of the present study was to investigate the impact of PLLA on dermal collagen synthesis by activating Piezo1 in both an H2O2-induced cellular senescence model in vitro and aged animal skin in vivo. PLLA elevated intracellular Ca2+ levels in senescent fibroblasts, which was attenuated by the Piezo1 inhibitor GsMTx4. Furthermore, PLLA treatment increased the expression of phosphorylated ERK1/2 to total ERK1/2 (pERK1/2/ERK1/2) and phosphorylated AKT to total AKT (pAKT/AKT), indicating enhanced pathway activation. This was accompanied by upregulation of cell cycle-regulating proteins (CDK4 and cyclin D1), promoting the proliferation of senescent fibroblasts. Additionally, PLLA promoted the expression of phosphorylated mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III in senescent fibroblasts, with GsMTx4 treatment mitigating these effects. In aged skin, PLLA treatment similarly upregulated the expression of pERK1/2/ERK1/2, pAKT/AKT, CDK4, cyclin D1, mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III. In summary, our findings suggest Piezo1's involvement in PLLA-induced collagen synthesis, mediated by heightened activation of cell proliferation signaling pathways such as pERK1/2/ERK1/2, pAKT/AKT, and phosphorylated mTOR/S6K1/4EBP1, underscoring the therapeutic potential of PLLA in tissue regeneration.

Facial skin rejuvenation with poly-l-lactic acid (PLLA): Four case studies

Background: Facial aging is characterized by the decline and loss of skin structure. Poly-l-lactic acid (PLLA) is a biopolymer and biodegradable injection material that functions as a collagen stimulator. This active ingredient works by stimulating the formation of skin collagen after interacting with the PLLA crystal component. The expected final result is an increase in the skin volume with the thickening and increased density of the skin layers due to collagen remodeling. At present, data on the application of PLLA for facial photorejuvenation remains limited. Case Illustration: Four patients aged 22-49 years old, with different severity of aging, underwent PLLA injection procedures. The active component was administered through injection with a dilution ratio of 1:1 to 1:2 for the cheeks and temporal area and without dilution for the forehead, smile lines, and chin area. After the injection, a gentle massage was performed, and the patient was instructed to self-massage every day. Each patient was evaluated on the twentieth day and underwent additional injection sessions up to two times. Discussion: All patients showed improvement as assessed using photography and the Global Aesthetic Improvement Scale (GAIS) 20 days after the procedure. All patients were satisfied with the final result. There was no significant pain during the procedure. Conclusion: PLLA injection is a safe and effective procedure that stimulates the formation of new collagen adequately. Patient satisfaction with the treatment was excellent, and no complications were observed in all patients.

Shelf Life of Minced Pork in Vacuum-Adsorbed Carvacrol@Natural Zeolite Nanohybrids and Poly-Lactic Acid/Triethyl Citrate/Carvacrol@Natural Zeolite Self-Healable Active Packaging Films.

Enhancing food preservation and safety using environmentally friendly techniques is urgently needed. The aim of this study was to develop food packaging films using biodegradable poly-L-lactic acid (PLA) as biopolymer and carvacrol (CV) essential oil as an antioxidant/antibacterial agent for the replacement of chemical additives. CV was adsorbed onto natural zeolite (NZ) via a new vacuum adsorption method. The novel nanohybrid CV@NZ with a high CV content contained 61.7%wt. CV. Pure NZ and the CV@NZ nanohybrid were successfully dispersed in a PLA/triethyl citrate (TEC) matrix via a melt extrusion process to obtain PLA/TEC/xCV@NZ and PLA/TEC/xNZ nanocomposite films with 5, 10, and 15%wt CV@NZ or pure NZ content. The optimum resulting film PLA/TEC/10CV@NZ contained 10%wt. CV@NZ and exhibited self-healable properties, 22% higher tensile strength, 40% higher elongation at break, 45% higher water barrier, and 40% higher oxygen barrier than the pure PLA/TEC matrix. This film also had a high CV release content, high CV control release rate as well as 2.15 mg/L half maximal effective concentration (EC50) and 0.27 mm and 0.16 mm inhibition zones against Staphylococcus aureus and Salmonella enterica ssp. enterica serovar Typhimurium, respectively. This film not only succeeded in extending the shelf life of fresh minced pork, as shown by the total viable count measurements in four days but also prevented the lipid oxidation of fresh minced pork and provided higher nutritional values of the minced meat, as revealed by the heme iron content determination. It also had much better and acceptable sensory characteristics than the commercial packaging paper.

Comprehensive Systematic Review of Poly-L-lactic Acid in Facial Clinical Application.

With the increasing global clinical application of regenerative injection materials, there is a growing recognition of the crucial role played by poly-L-lactic acid (PLLA). The aim of this study is to conduct a systematic review on the therapeutic efficacy and safety of PLLA in clinical applications for facial treatments. We conducted a search of the PubMed, EMBASE, Web of Science, and Wanfang databases, followed by screening of the retrieved articles based on predefined inclusion and exclusion criteria. We then performed an analysis on the final set of included articles that met our inclusion criteria. Within these included articles, quality assessment for randomized controlled trials (RCTs) was carried out using the Jadad scale, while non-randomized controlled trials (non-RCTs) were evaluated using the MINORS scale. Our search of above database, using the relevant search terms, yielded a total of 1300 PLLA-related articles. After applying the inclusion and exclusion criteria, 1280 articles were excluded. Only 20 articles, 16 in English and 4 in Chinese, were included in our final analysis, among them 16 NRCTs and 4 RCTs. According to the different clinical evaluation standards, the treatment of PLLA has achieved good outcomes. Most PLLA injection-related adverse events are mild and self-limited, without any additional treatment requirement. PLLA is a reasonably safe and effective facial injection material that can be applied in different facial injection areas and depth using various reconstitute and injection methods. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparative three-dimensional maxillary stability assessment: Bioresorbable miniplate vs. titanium miniplate systems in Le Fort I osteotomy

ObjectiveThis study aimed to evaluate the usefulness of bioresorbable miniplates by comparing the three-dimensional maxillary stability of poly L-lactic acid and titanium miniplate systems in Le Fort I osteotomy. MethodsFifty patients with jaw deformities underwent Le Fort I or bilateral sagittal split osteotomies. The patients were divided into two groups: the first group received the polylactic acid miniplate system for bone fixation, while the second group received the titanium miniplate system. Cone-beam computed tomography (CBCT) was performed before surgery and at 1 and 6 months after surgery. The acquired images were overlapped to quantify the extent of maxillary relapse by calculating the difference in the distance moved between 1 and 6 months after surgery. ResultsThere was no significant difference in maxillary stability between the two groups 6 months after surgery. ConclusionsThe postoperative stability achieved using the poly L-lactic acid miniplate system for maxillary fixation was comparable to that achieved using the titanium miniplate system.

Poly-l-Lactic Acid Scaffolds Additivated with Rosmarinic Acid: A Multi-Analytical Approach to Assess The Morphology, Thermal Behavior, and Hydrophilicity.

This study aims to demonstrate the possibility of incorporating a natural antioxidant biomolecule into polymeric porous scaffolds. To this end, Poly-l-Lactic Acid (PLLA) scaffolds were produced using the Thermally Induced Phase Separation (TIPS) technique and additivated with different amounts of rosmarinic acid (RA). The scaffolds, with a diameter of 4 mm and a thickness of 2 mm, were characterized with a multi-analytical approach. Specifically, Scanning Electron Microscopy analyses demonstrated the presence of an interconnected porous network, characterized by a layer of RA at the level of the pore's surfaces. Moreover, the presence of RA biomolecules increased the hydrophilic nature of the sample, as evidenced by the decrease in the contact angle with water from 128° to 76°. The structure of PLLA and PLLA containing RA molecules has been investigated through DSC and XRD analyses, and the obtained results suggest that the crystallinity decreases when increasing the RA content. This approach is cost-effective, and it can be customized with different biomolecules, offering the possibility of producing porous polymeric structures containing antioxidant molecules. These scaffolds meet the requirements of tissue engineering and could offer a potential solution to reduce inflammation associated with scaffold implantation, thus improving tissue regeneration.