Nano, micro particulate and cosmetic delivery systems of polylactic acid: A mini review

Enhanced biodegradation of polylactic acid by Aspergillus oryzae lipase: Toward sustainable plastic end-of-life solutions

This study investigates the enhanced biodegradation of polylactic acid (PLA) films and microparticles using a commercial lipase enzyme from Aspergillus oryzae. To evaluate the effect of pH on the bioprocess efficiency, the enzymatic hydrolysis of PLA films was initially examined at pH values ranging from 7.0 to 8.5, at 37℃, for 28 days, using an enzyme activity of 2,425 U/mL. Changes in the surface morphology and chemical structure of the films were more pronounced at pH 8.0, while it was found that the lipase preferentially targets the amorphous regions of PLA, leaving its crystalline structures intact during the treatment period. The treated PLA films exhibited significant alterations in their surface morphology, with enhanced roughness and increased hydrophilicity compared to the untreated films. Using pH 8.0 as the optimum condition, the effect of higher lipase enzyme activities on the biodegradation of both PLA films and microparticles was studied, showing a clear acceleration in enzymatic hydrolysis. Additionally, the production of lactic acid during the degradation process was confirmed through high-performance liquid chromatography. These findings highlight the potential of enzymatic approaches to efficiently degrade PLA-based materials, enabling their bioconversion into valuable lactic acid monomers. By addressing the end-of-life challenges of PLA, this work demonstrates its viability as a sustainable alternative to conventional plastics, contributing to a circular economy and reducing environmental impact.

Enhancing Skin Regeneration Efficacy of Human Dermal Fibroblasts Using Carboxymethyl Cellulose-Coated Biodegradable Polymer

BACKGROUND

Polylactic acid (PLA) is extensively used in the medical and cosmetic industries for skin regeneration and as a dermal filler due to its biocompatibility and biodegradability. However, the effectiveness of PLA as a cosmetic filler is limited by its slow degradation rate and poor cell attachment properties. Recent studies have focused on enhancing the performance of PLA by combining it with other materials. This study aimed to evaluate the performance of carboxymethyl cellulose (CMC), known for its high biocompatibility, in comparison with the widely used hyaluronic acid (HA).

METHODS

Two types of PLA-based particles, HA-PLA and CMC-PLA were synthesized by combining PLA with HA and CMC, respectively. After characterizing the particles, we evaluated cell adhesion and viability using human dermal fibroblasts and analyzed gene and protein expression related to cell attachment and angiogenic paracrine factors.

RESULTS

The CMC-PLA particles maintained a more uniform size distribution than the HA-PLA particles and exhibited superior cell adhesion properties. Cells attached on the CMC-PLA particles showed enhanced secretion of angiogenic paracrine factors, suggesting a potential improvement in therapeutic efficacy.

CONCLUSION

CMC-PLA particles demonstrated superior cell adhesion and secretion capabilities compared with HA-PLA particles, indicating their potential for application in skin regeneration and tissue recovery. Further research, including in vivo studies, is required to fully explore and validate the therapeutic potential of CMC-PLA particles.

Exosome-Based Therapeutics in Dermatology

Exosomes (Exos) are tiny extracellular vesicles containing a variety of active biomolecules that play important parts in intercellular communication and influence the functions of target cells. The potential of Exos in the treatment of dermatological diseases has recently been well appreciated. This review highlights the constituents, function, and delivery of Exos, with a particular focus on their applications in skin therapy. Firstly, we offer a concise overview of the biochemical properties of Exos, including their sources, structures, and internal constituents. Subsequently, the biomedical functions of Exos and the latest advances in the extraction and purification of Exos are summarized. We further discuss the modes of delivery of Exos and underscore the potential of biomaterials in this regard. Finally, we summarize the application of Exo-aided therapy in dermatology. Overall, the objective of this review is to provide a comprehensive perspective on the applications and recent advancements of Exo-based approaches in treating skin diseases, with the intention of guiding future research efforts.

Biodegradable Fiber Preparation Technique to Meet Industrial Requisites Through Sheath-Core Melt-Spinning

Biodegradable polymers are essential for sustainable plastic life cycles and contribute to a carbon-neutral society. Here, we explore the development of biodegradable fibers with excellent mechanical properties using polypropylene (PP) and thermoplastic starch (TPS) blends. To address the inherent immiscibility between hydrophobic PP and hydrophilic TPS, hydrophilic modification and a masterbatch approach were employed. Melt-spinning trials demonstrated that the modified PP and TPS blends (mPP/TPS) exhibited excellent spinnability and processability comparable to virgin PP. A sheath-core configuration was introduced to enhance biodegradability while maintaining structural stability, with an mPP-rich part as the core and a TPS-rich part with a biodegradable promoter (BP) as the sheath. SEM and DSC analyses confirmed strong interfacial compatibility, uniform fiber morphology, and single melting points, indicating no phase separation. Mechanical testing showed that the sheath-core fibers met industrial requirements, achieving a tenacity of up to 2.47 gf/den and tensile strain above 73%. The addition of a BP increased the biodegradability rate, with PP/TPS/BP fibers achieving 65.93% biodegradation after 115 days, compared to 37.00% for BP-free fibers. These results demonstrate the feasibility of blending petroleum-based polymers with bio-based components to create fibers that balance biodegradability, spinnability, and mechanical performance, offering a sustainable solution for industrial applications.

Preparation and Evaluation of Complexed Ubiquinone (Coenzyme Q10) Antiaging Hyaluronic Acid-Vitamin C Serum for Skin Care

BACKGROUND

Coenzyme Q10 (CoQ10) is widely recognized for its powerful antioxidant properties, sparking considerable interest in its application within skincare treatments. However, its inherently poor water solubility has posed a major challenge in formulating effective skincare products.

METHODS

This research aimed to develop and evaluate a water-soluble CoQ10 serum by forming a complex with hydroxypropyl β-cyclodextrin (HPβCD). The study focused on assessing its physicochemical properties, CoQ10 concentration, spread ability, viscosity, pH, physical stability, irritation potential, and diffusion performance. The complexation process was carried out using kneading and trituration techniques, with thorough characterization via validated analytical methods such as solubility tests, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) analyses.

RESULTS

The CoQ10-HPβCD complex prepared using the trituration technique at a 2:1 ratio (CoQ10 to HPβCD) demonstrated superior water solubility, reaching 17.5 ± 1.8 mg mL-1, the highest among the tested formulations. Moreover, this formulation achieved the greatest encapsulation efficiency, retaining 71% ± 3.8% of CoQ10. FTIR and DSC analyses confirmed the successful formation of the complex. The formulated serum exhibited shear-thinning behavior, an optimal pH of 4.3 ± 0.2 closely aligning with the skin's natural acidity for enhanced compatibility-along with excellent spreadability and stability. Diffusion tests revealed a significant enhancement in solubility when CoQ10 was complexed, effectively overcoming its solubility barrier. Irritation tests validated the serum's safety for topical use.

CONCLUSION

This study successfully developed a CoQ10 serum that overcame its solubility limitation, demonstrating favorable properties for skincare application. With its strong physicochemical characteristics and biocompatibility, this formulation shows significant promise for broader incorporation into skincare products.

Medical applications and prospects of polylactic acid materials

Polylactic acid (PLA) is a biodegradable and bio-based polymer that has gained significant attention as an environmentally friendly alternative to traditional petroleum-based plastics. In clinical treatment, biocompatible and non-toxic PLA materials enhance safety and reduce tissue reactions, while the biodegradability allows it to breakdown over time naturally, avoiding a second surgery. With the emergence of nanotechnology and three-dimensional (3D) printing, medical utilized-PLA has been produced with more structural and biological properties at both micro and macro scales for clinical therapy. This review summarizes current applications of the PLA-based biomaterials in drug delivery systems, orthopedic treatment, tissue regenerative engineering, and surgery and medical devices, providing viewpoints regarding the prospective medical utilization.

Microplastics in Cosmetics: Open Questions and Sustainable Opportunities

The cosmetic industry is now changing or rather having an ecological transition in which formulations such as creams, lotions, and powders for make-up, skin and hair care must not contain microplastics, now a taboo word in this field. Nowadays, many companies are intensifying their research and development (R&D) work to align with recent and future legislation that provides for their elimination to safeguard the ecosystem. The production of new eco-sustainable materials is currently a hot topic which finds its place in a market worth above 350 billion dollars which will reach more than 700 billion dollars in a very short time. This review offers an overview of the main advantages and adverse issues relating to the use of microplastics in cosmetics and of their impact, providing an insight into the properties of the polymeric materials that are currently exploited to improve the sensorial characteristics of cosmetic products. In addition, the various regulatory restrictions in the different geographical areas of the world are also described, which is matter for reflection on future direction. Finally, a prospective vision of possible solutions to replace microplastics with sustainable alternatives complete the picture of the next generation personal care products to support decision-making in the cosmetic marketplace.

In vitro evaluation of lipidic nanocarriers for mebendazole delivery to improve anticancer activity

OBJECTIVE

To enhance the anticancer activity of the repurposed drug mebendazole (MBZ) against A549 cell lines by developing nanostructured lipid carriers (NLCs).

SIGNIFICANCE

MBZ, an anthelmintic drug, exhibits anticancer properties primarily through the inhibition of Ran GTPase and mitotic spindle assembly. Enhancing its delivery and efficacy via NLC could provide a novel and effective approach for lung cancer treatment.

METHODS

NLCs were prepared by mixing different ratios of solid lipid (stearic acid) and liquid lipid (oleic acid) with surfactants and emulsifiers. The NLCs were fully characterized to ensure stability, particle size, zeta potential, and encapsulation efficiency (EE%). The stability of the NLCs was monitored over a 3-week period. The anticancer activity of MBZ-NLCs was evaluated using IC50 assays and in vitro scratch assays.

RESULTS

The NLCs exhibited an average particle size of 300 ± 10 nm and a zeta potential of -27 ± 0.5 mV, indicating good stability. EE% significantly improved from 40% in conventional liposome formulations to 90.7% in NLCs. The anticancer activity of MBZ-NLCs was markedly enhanced, with an IC50 of 62 nM compared to 581 nM for free MBZ, representing a 10-fold increase in potency. Additionally, in vitro scratch assays revealed that MBZ-NLCs effectively prevented cell-cell contact, further supporting their potential for improved therapeutic efficacy.

CONCLUSION

MBZ-NLCs exhibit significantly improved stability, EE%, and anticancer activity compared to free MBZ. These promising results suggest that MBZ-NLCs could be a potent therapeutic approach for lung cancer treatment, warranting further in vivo studies and exploration of different administration routes.

Advancements of metallic nanoparticles: A promising frontier in cancer treatment

The incidence of cancer is increasing and evolving as a major source of mortality. Nanotechnology has garnered considerable scientific interest in recent decades and can offer a promising solution to the challenges encountered with traditional chemotherapy. Nanoparticle utilization holds promise in combating cancer and other diseases, offering exciting prospects for drug delivery systems and medicinal applications. Metallic nanoparticles exhibit remarkable physical and chemical properties, such as their minute size, chemical composition, structure, and extensive surface area, rendering them versatile and cost-effective. Research has demonstrated their significant and beneficial impact on cancer treatment, characterized by enhanced targeting abilities, gene activity suppression, and improved drug delivery efficiency. By incorporating targeting ligands, functionalized metal nanoparticles ensure precise energy deposition within tumors, thereby augmenting treatment accuracy. Moreover, beyond their therapeutic efficacy, metal nanoparticles serve as valuable tools for cancer cell visualization, contributing to diagnostic techniques. Utilizing metal nanoparticles in therapeutic systems allows for simultaneous cancer diagnosis and treatment, while also facilitating controlled drug release, thus revolutionizing cancer care. This narrative review investigates the advancements of metal nanoparticles in cancer treatment, types and mechanisms in targeting cancer cells, application in clinical scenarios, and potential toxicity in medicine.

Poly-d,l-lactic Acid (PDLLA) Application in Dermatology: A Literature Review

Poly-d,l-lactic acid (PDLLA) is a biodegradable and biocompatible polymer that has garnered significant attention in dermatology due to its unique properties and versatile applications. This literature review offers a comprehensive analysis of PDLLA's roles in various dermatological conditions and wound-healing applications. PDLLA demonstrates significant benefits in enhancing skin elasticity and firmness, reducing wrinkles, and promoting tissue regeneration and scar remodeling. Its biodegradable properties render it highly suitable for soft tissue augmentation, including facial and breast reconstruction. We discuss the critical importance of understanding PDLLA's physical and chemical characteristics to optimize its performance and safety, with a focus on how nano- and micro-particulate systems can improve delivery and stability. While potential complications, such as granuloma formation and non-inflammatory nodules, are highlighted, effective monitoring and early intervention strategies are essential. PDLLA's applications extend beyond dermatology into orthopedics and drug delivery, owing to its superior mechanical stability and biocompatibility. This review underscores the need for ongoing research to fully elucidate the mechanisms of PDLLA and to maximize its therapeutic potential across diverse medical fields.

Encapsulation of gingerol into nanoliposomes: Evaluation of in vitro anti-inflammatory and anti-cancer activity

Nanoliposomes (NLs) are ideal carriers for delivering complex molecules and phytochemical products, but ginger by-products, despite their therapeutic benefits, have poor bioavailability due to their low water solubility and stability. Crude ginger extracts (CGEs) and 6-gingerol were individually encapsulated within NLs for in vitro activity assessment. In vitro evaluation of anti-proliferative and anti-inflammatory properties of encapsulated 6-gingerol and CGE was performed on healthy human periodontal ligament (PDL) fibroblasts and MDA-MB-231 breast cancer cells. Encapsulation efficiency and loading capacity of 6-gingerol reached 25.23% and 2.5%, respectively. NLs were found stable for up to 30 days at 4°C with a gradual load loss of up to 20%. In vitro cytotoxic effect of encapsulated 6-gingerol exceeded 70% in the MDA-MB-231 cell line, in a comparable manner with non-encapsulated 6-gingerol and CGE. The effect of CGE with an IC50 of 3.11 ± 0.39, 7.14 ± 0.80, and 0.82 ± 0.55 μM and encapsulated 6-gingerol on inhibiting IL-8 was evident, indicating its potential anti-inflammatory activity. Encapsulating 6-gingerol within NLs enhanced its stability and facilitated its biological activity. All compounds, including vitamin C, were equivalent at concentrations below 2 mg/mL, with a slight difference in antioxidant activity. The concentrations capable of inhibiting 50% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) substrate were comparable.

Optimized Synthesis of Poly(Lactic Acid) Nanoparticles for the Encapsulation of Flutamide

Biopolymeric nanoparticles (NPs) have gained significant attention in several areas as an alternative to synthetic polymeric NPs due to growing environmental and immunological concerns. Among the most promising biopolymers is poly(lactic acid) (PLA), with a reported high degree of biocompatibility and biodegradability. In this work, PLA NPs were synthesized according to a controlled gelation process using a combination of single-emulsion and nanoprecipitation methods. This study evaluated the influence of several experimental parameters for accurate control of the PLA NPs' size distribution and aggregation. Tip sonication (as the stirring method), a PLA concentration of 10 mg/mL, a PVA concentration of 2.5 mg/mL, and low-molecular-weight PLA (Mw = 5000) were established as the best experimental conditions to obtain monodisperse PLA NPs. After gelification process optimization, flutamide (FLU) was used as a model drug to evaluate the encapsulation capability of the PLA NPs. The results showed an encapsulation efficiency of 44% for this cytostatic compound. Furthermore, preliminary cell viability tests showed that the FLU@PLA NPs allowed cell viabilities above 90% up to a concentration of 20 mg/L. The comprehensive findings showcase that the PLA NPs fabricated using this straightforward gelification method hold promise for encapsulating cytostatic compounds, offering a novel avenue for precise drug delivery in cancer therapy.

Investigating the efficacy of topical application of Ipomoea carnea herbal cream in preventing skin damage induced by UVB radiation in a rat model

Ultraviolet-B irradiation is a common environmental stressor that has detrimental effects on human skin. Natural sunscreens are well-known for their ability to benefit inflamed sunburn and dry skin. This study examined the effect of formulated Ipomoea carnea herbal cream on UVB-induced skin damage. We screened the bioactive compounds of I. carnea crude extract, showing significant antioxidant activity. Additionally, we evaluated the cytotoxicity, revealing that I. carnea extract has less toxicity to vero cells (IC50 98.45 μg/mL) than to A375 cells (IC50 48.95 μg/mL). Based on this, we formulated the I. carnea herbal cream (FIHC) at 50, 100 and 200 mg concentrations and evaluated its organoleptic characteristics. Then, the rats were exposed to UVB radiation (32,800 J/m2) four times/week (on alternate days) before the cream was applied topically to the dorsal skin surface. Under UVB stress without treatment, rats showed deep dermal damage. In contrast, rats treated with the FIHC exhibited significantly reduced sunburn. Moreover, the histopathological and biochemical assays were confirmed by the topical application of FIHC, which had potentially reduced the skin elasticity and maintained the imbalanced enzyme and non-enzymatic antioxidant activity. Our findings amply demonstrate that the FIHC significantly accelerated the recovery of UVB-induced lesions through antioxidant and down-regulation of skin photodamage.

Synergistic Effects of AgNPs and Biochar: A Potential Combination for Combating Lung Cancer and Pathogenic Bacteria

The synthesis of reliable biological nanomaterials is a crucial area of study in nanotechnology. In this study, Emericella dentata was employed for the biosynthesis of AgNPs, which were then combined with synthesized biochar, a porous structure created through biomass pyrolysis. The synergistic effects of AgNPs and biochar were evaluated through the assessment of pro-inflammatory cytokines, anti-apoptotic gene expression, and antibacterial activity. Solid biosynthesized AgNPs were evaluated by XRD and SEM, with SEM images revealing that most of the AgNPs ranged from 10 to 80 nm, with over 70% being less than 40 nm. FTIR analysis indicated the presence of stabilizing and reducing functional groups in the AgNPs. The nanoemulsion's zeta potential, hydrodynamic diameter, and particle distribution index were found to be -19.6 mV, 37.62 nm, and 0.231, respectively. Biochar, on the other hand, did not have any antibacterial effects on the tested bacterial species. However, when combined with AgNPs, its antibacterial efficacy against all bacterial species was significantly enhanced. Furthermore, the combined material significantly reduced the expression of anti-apoptotic genes and pro-inflammatory cytokines compared to individual treatments. This study suggests that low-dose AgNPs coupled with biochar could be a more effective method to combat lung cancer epithelial cells and pathogenic bacteria compared to either substance alone.

Formulating co-loaded nanoliposomes with gallic acid and quercetin for enhanced cancer therapy

Cancer is considered one of the top global causes of death. Natural products have been used in oncology medicine either in crude form or by utilizing isolated secondary metabolites. Biologically active phytomolecules such as gallic acid and quercetin have confirmed antioxidant, anti-bacterial, and neoplastic properties. There is an agreement that microorganisms could mediate oncogenesis or alter the immune system. This research project aims to develop a novel formulation of co-loaded gallic acid and quercetin into nanoliposomes and investigate the efficacy of the free and combined agents against multiple cancerous cell lines and bacterial strains. Thin-film hydration technique was adopted to synthesize the nanocarriers. Particle characteristics were measured using a Zetasizer. The morphology of nanoliposomes was examined by scanning electron microscopy, Encapsulation efficiency and drug loading were evaluated using High-Performance Liquid Chromatography. Cytotoxicity was determined against Breast Cancer Cells MCF-7, Human Carcinoma Cells HT-29, and A549 Lung Cancer Cells. The antibacterial activities were evaluated against Acinetobacter baumannii, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Staphylococcus aureus. Therapeutic formulas were categorized into groups: free gallic acid, free quercetin, free-mix, and their nano-counterparts. Findings revealed that drug loading capacity was 0.204 for the mix formula compared to 0.092 and 0.68 for free gallic acid and quercetin, respectively. Regarding the Zeta potential, the mix formula showed more amphiphilic charge than the free quercetin and free gallic acid formulas (P-values 0.003 and 0.002 receptively). On the contrary, no significant difference in polydispersity indices was reported. Lung cancerous cells were the most affected by the treatments. The best estimated IC50 values were observed in breast and lung cancer lines for the nano-gallic acid and co-loaded particles. The nano-quercetin formula exhibited the least cytotoxicity with an IC50 value of ≥200 μg/mL in both breast (MCF-7) and colorectal adenocarcinoma cell lines (HT-29) with no activity against the lung. A remarkable improvement in the efficacy of quercetin was measured after mixing it with gallic acid against the breast and lungs. The tested therapeutic agents exhibited antimicrobial activity against gram-positive bacteria. Nano-liposomes can either enhance or reduce the cytotoxicity activity of active compounds depending on the physical and chemical properties of drug-loaded and type of cancer cells.

Fungal-Mediated Silver Nanoparticle and Biochar Synergy against Colorectal Cancer Cells and Pathogenic Bacteria

Background: Silver nanoparticles (AgNPs) are attractive substrates for new medicinal treatments. Biochar is pyrolyzed biomass. Its porous architecture allows it to hold and gather minuscule particles, through which nanoparticles can accumulate in its porous structure. This study examined AgNPs’ antibacterial and anticancer properties alone and combined with biochar. Methods: The fungus Emericella dentata was responsible for biosynthesis of AgNPs. The characterization of AgNPs using STEM images and a Zetasizer was carried out. Accordingly, the antibacterial and antiproliferation activity of AgNPs and biochar was studied using MIC and MTT assays, respectively. To evaluate the antiangiogenic and anti-inflammatory effects of AgNPs with biochar, VEGF and cytokines including TNF alpha, IL-6 and IL-beta were tested using an ELISA assay. Results: The size of the AgNPs ranged from 10 to 80 nm, with more than 70% of them being smaller than 40 nm. The combination of AgNPs and biochar enhanced the antibacterial activity against all tested bacteria. Furthermore, this combination showed antiproliferative properties against HT29 cancer cells with high selectivity to fibroblasts at low concentrations. AgNPs with biochar significantly reduced VEGF and proinflammatory cytokine expression levels. Conclusions: Biochar and AgNPs may be novel treatments for bacteria and colorectal cancer cells, according to the current findings.

The revolution of cosmeceuticals delivery by using nanotechnology: A narrative review of advantages and side effects

BACKGROUND

The qualified and paradigm jump in the formulation and production of cosmeceuticals refer in some way to the great revolution in nanotechnology. Nowadays, the industry of nano-formulated cosmeceuticals plays a significant and essential role in the evolution and growth of the pharmaceutical industries. This review manuscript focuses on the use of nanocarriers in delivering the cosmetic agents into the target area such as skin, hair, and nails.

METHODS

Many steps were performed in the preparation of this review including identification of different classes of nanocarriers for delivery of nanocosmeceuticals, literature survey of relevantstudies regarding the applications of nanotechnology in cosmeceuticals and their toxicological effects.

RESULTS

When nanoparticles introduced in the cosmetic industry, the quality and the elegance of the final products were raised significantly. Sadly, this revolution is accompanied by many health hazards as these tiny molecules can penetrate intact skin barriers and cause undesired effects. Cosmeceuticals with nanotechnology include sunscreens, hair cleansing products, nail products, and agents fighting fine lines.

CONCLUSIONS

The expansion and growth of the cosmetic industry and the introduction of nanotechnology in cosmeceuticals industry necessitates the urgent need for scientific research investigating their efficacy, safety profile and use.

Towards a selective synthetic route for cobalt amino acid complexes and their application in ring opening polymerization of rac-lactide

Catalysts based on cobalt amino acids and 2,2 bipyridine (bipy) present an attractive and cost-effective alternative as ring opening polymerization catalysts, yet this system remains underexplored despite the advantageous coordination properties of amino acids and bipy as ligands combined with the variety of accessible oxidation states and coordination geometries of cobalt. Here, metal complexes of type [Co(aa)2(bipy)] with amino acids (aa: glycine, leucine and threonine) as ligands are reported. The complexes were characterized spectroscopically (IR, UV-vis and 1H, 13C NMR for diamagnetic species), and by MS spectrometry and elemental analysis. The data reveal that the 2,2 bipyridine acts as a neutral bidentate donor coordinating to the metal ion through two nitrogen atoms and the amino acid acts as a bidentate ligand coordinating through the carboxylate and amino group forming a stable five membered ring and a pseudo-octahedral geometry around the Co center. The activity of the complexes for the ring opening polymerization (ROP) of rac-lactide is presented. The complexes are effective initiators for the ROP of rac-lactide (K obs = 9.05 × 10-4 s-1) at 100 : 1 [rac-lactide] : [catalyst] 1 M overall concentration of lactide in toluene at 403 K.

Molecular Dynamics Studies of Poly(Lactic Acid) Nanoparticles and Their Interactions with Vitamin E and TLR Agonists Pam1CSK4 and Pam3CSK4

Poly(lactic acid) (PLA) nanoparticles (NPs) are widely investigated due to their bioresorbable, biocompatible and low immunogen properties. Interestingly, many recent studies show that they can be efficiently used as drug delivery systems or as adjuvants to enhance vaccine efficacy. Our work focuses on the molecular mechanisms involved during the nanoprecipitation of PLA NPs from concentrated solutions of lactic acid polymeric chains, and their specific interactions with biologically relevant molecules. In this study, we evaluated the ability of a PLA-based nanoparticle drug carrier to vectorize either vitamin E or the Toll-like receptor (TLR) agonists Pam₁CSK₄ and Pam₃CSK₄, which are potent activators of the proinflammatory transcription factor NF-κB. We used dissipative particle dynamics (DPD) to simulate large systems mimicking the nanoprecipitation process for a complete NP. Our results evidenced that after the NP formation, Pam₁CSK₄ and Pam₃CSK₄ molecules end up located on the surface of the particle, interacting with the PLA chains via their fatty acid chains, whereas vitamin E molecules are buried deeper in the core of the particle. Our results allow for a better understanding of the molecular mechanisms responsible for the formation of the PLA NPs and their interactions with biological molecules located either on their surfaces or encapsulated within them. This work should allow for a rapid development of better biodegradable and safe vectorization systems with new drugs in the near future.