A development of a gelatin and sodium carboxymethyl cellulose hydrogel system for dual-release transdermal delivery of lidocaine hydrochloride

This study introduces a dual-release transdermal drug delivery system using a hydrogel matrix of cross-linked gelatin and sodium carboxymethyl cellulose (NaCMC). Designed for immediate drug release from microneedles (MNs) and sustained release from microcapsules (MCs), this system utilizes lidocaine hydrochloride as the model drug. The fabrication process involved casting the hydrogel into MN molds, with MCs embedded in the backing layer, establishing a dual-release mechanism. MCs of gelatin and NaCMC were prepared by emulsion-crosslinking method and using glutaraldehyde as a crosslinker. MCs ranged in size from 50 to 264 μm and exhibited the highest drug release in acidic environments, showcasing a pH-responsive nature. Drug loading efficiency reached 9.8 %, while encapsulation efficiency was 75.8 %. The MNs, which had a conical shape and strong mechanical properties, demonstrated excellent penetration capabilities. The in vitro release profile indicated an initial burst within 10 min, followed by sustained release over 240 min, in line with the Korsmeyer-Peppas model. Additionally, the system displayed significant antimicrobial properties and good biocompatibility, with cell viability exceeding 86 %. This confirms its potential as a safe and effective platform for transdermal drug delivery.

Tribological Properties of Synthetic and Biosourced Lubricants Enhanced by Graphene and Its Derivatives: A Review

This review explores the tribological properties of biosourced lubricants (biolubricants) enhanced by graphene (Gr) and its derivatives and hybrids. Friction and wear at mechanical interfaces are the primary causes of energy loss and machinery degradation, necessitating effective lubrication strategies. Traditional lubricants derived from mineral oils present environmental challenges, leading to an increased interest in biolubricants derived from plant oils and animal fats. Biolubricants offer high biodegradability, renewability, and low toxicity, positioning them as ecofriendly alternatives. This work extensively reviews the role of Gr-based nanoadditives in enhancing the lubrication properties of biolubricants. Gr with its exceptional physicomechanical properties has shown promise in reducing friction and wear. The review covers various Gr derivatives, including Gr oxide (GO) and reduced Gr oxide (r-GO), and their performance as lubrication additives. The discussion extends to Gr hybrids with metals, polymers, and other 2D materials, highlighting their synergistic effects on the tribological performance. The mechanisms through which these additives enhance lubrication, such as the formation of protective films and improved interactions between lubricants and tribopairs, are examined. Emphasis is placed on the environmental benefits and potential performance improvements of Gr-based biolubricants. Finally, by analyzing current research and technological trends, the paper outlines future prospects for optimizing lubricant formulations with Gr-based nanoadditives, aiming for more sustainable and efficient tribological applications.

Recent Advances in Multifunctional Naturally Derived Bioadhesives for Tissue Engineering and Wound Management

Recent advancements in naturally derived bioadhesives have transformed their application across diverse medical fields, including tissue engineering, wound management, and surgery. This review focuses on the innovative development and multifunctional nature of these bioadhesives, particularly emphasizing their role in enhancing adhesion performance in wet environments and optimizing mechanical properties for use in dynamic tissues. Key areas covered include the chemical and physical mechanisms of adhesion, the incorporation of multi‐adhesion strategies that combine covalent and non‐covalent bonding, and bioinspired designs mimicking natural adhesives such as those of barnacles and mussels. Additionally, the review discusses emerging applications of bioadhesives in the regeneration of musculoskeletal, cardiac, neural, and ocular tissues, highlighting the potential for bioadhesive‐based therapies in complex biological settings. Despite substantial progress, challenges such as scaling lab‐based innovations for clinical use and overcoming environmental and mechanical constraints remain critical. Ongoing research in bioadhesive technologies aims to bridge these gaps, promising significant improvements in medical adhesives tailored for diverse therapeutic needs.

Nanogels in Biomedical Engineering: Revolutionizing Drug Delivery, Tissue Engineering, and Bioimaging

Nanogels represent a significant innovation in the fields of nanotechnology and biomedical engineering, combining the properties of hydrogels and nanoparticles to create versatile platforms for drug delivery, tissue engineering, bioimaging, and other biomedical applications. These nanoscale hydrogels, typically ranging from 10 to 1000 nm, possess unique characteristics such as high water content, biocompatibility, and the ability to encapsulate both hydrophilic and hydrophobic molecules. The review explores the synthesis, structural configurations, and stimuli‐responsive nature of nanogels, highlighting their adaptability for targeted drug delivery, including across challenging barriers like the blood–brain barrier. Furthermore, the paper delves into the biomedical applications of nanogels, particularly in drug delivery systems, tissue engineering, and bioimaging, demonstrating their potential to revolutionize these fields. Despite the promising preclinical results, challenges remain in translating these technologies into clinical practice, including issues related to stability, scalability, and regulatory approval. The review concludes by discussing future perspectives, emphasizing the need for further research to optimize the properties and applications of nanogels, ultimately aiming to enhance their efficacy and safety in clinical settings.

Non-isocyanate polyurethane-co-polyglycolic acid electrospun nanofiber membrane wound dressing with high biocompatibility, hemostasis, and prevention of chronic wound formation

The prevention of chronic wound formation has already been a primary subject in wound management, particularly for deep wounds. The electrospun nanofiber membranes hold tremendous potential in the prevention of chronic wounds due to their micro/nano pore structures. Currently, many natural and synthetic materials have been utilized in the fabrication of nanofiber membranes. However, striking a balance between the structural stability and the biocompatibility remains challenging. It is necessary not only to ensure the long-term durability of nanofiber membranes but also to enhance their biocompatibility for alleviating patients' suffering. In this study, we reported a nanofiber membrane dressing with excellent biocompatibility and mechanical properties, which is potential for the treatment of deep wounds. The basal material chosen for the preparation of the nanofiber membrane was a co-polyester (NI-LPGD5) synthesized by non-isocyanate polyurethane (NIPU) and polyglycolic acid with a dihydroxy structure (LPGD-synthesized from glycolic acid and neopentyl glycol). Moreover, curcumin was also added as a bioactive substance to enhance the pro-healing effect of dressings. The physicochemical properties of the prepared nanofiber membranes were characterized through various physicochemical tools. Our results demonstrated that the NI-LPGD5 co-polymer can be electrospun into smooth fibers. Meanwhile, curcumin-loaded nanofiber membranes (Cur/NI-LPGD5) also exhibited a favorable microscopic morphology. The fabricated membranes exhibited suitable mechanical properties, outstanding hygroscopic-swelling rate and water vapor transmittance. Besides, in vitro cell culturing, the cells on the NI-LPGD5 membrane maintained their maximum viability. The potential of in vivo wound healing was further demonstrated through animal experiments. The experimental results showed that the nanofiber membranes effectively prevented chronic wounds from forming and promoted granulation tissue growth without replacing the dressing throughout the healing process. We also found that these nanofiber membranes could effectively promote the expression of related biomarkers to accelerate wound healing, particularly the Cur/NI-LPGD5 membrane. In conclusion, the fabricated membranes possess suitable physicochemical properties and promising bioactivity. As a result, it effectively prevented the formation of chronic wounds and demonstrated significant potential in reducing the frequency of dressing changes.

Curcumin-loaded scaffolds in bone regeneration

In recent years, there has been a notable surge in the development of engineered bone scaffolds intended for the repair of bone defects. While autografts and allografts have traditionally served as the primary methods in bone tissue engineering, their inherent limitations have spurred the exploration of novel avenues in biomedical implant development. The emergence of bone scaffolds not only facilitates bone reconstruction but also offers a platform for the targeted delivery of therapeutic agents. There exists a pervasive interest in leveraging various drugs, proteins, growth factors, and biomolecules with osteogenic properties to augment bone formation, as the enduring side effects associated with current clinical modalities necessitate the pursuit of safer alternatives. Curcumin, the principal bioactive compound found in turmeric, has demonstrated notable efficacy in regulating the proliferation and differentiation of bone cells while promoting bone formation. Nevertheless, its utility is hindered by restricted water solubility and poor bioavailability. Strategies aimed at enhancing the solubility, stability, and bioavailability of curcumin, including formulation techniques such as liposomes and nanoparticles or its complexation with metals, have been explored. This investigation is dedicated to exploring the impact of curcumin on the proliferation, differentiation, and migration of osteocytes, osteoblasts, and osteoclasts.

Tunable structure and linear viscoelastic properties of poly(glycerol adipate urethane)-based elastomeric composites for tissue regeneration

Elastomeric biocomposites based on poly(glycerol adipate urethane) and hydroxyapatite were fabricated for tissue regeneration. The poly(glycerol adipate urethane) (PGAU) elastomeric composite matrices were obtained by chemical crosslinking of the poly(glycerol adipate) prepolymer (pPGA) with diisocyanate derivative of L-lysine. Two series of composites varying in the amount of L-lysine diisocyanate ethyl ester (LDI) used as a crosslinking agent were manufactured. As a ceramic filler both unmodified and L-lysine surface-modified hydroxyapatite (HAP) particles were used. The novelty of our research consists in the manufactured elastomeric materials and characterization of their linear viscoelastic (LVE) properties. The LVE properties of the composites were investigated by means of dynamic thermomechanical analysis. Frequency sweep and amplitude sweep measurements were performed in shear mode. The influence of the crosslinking agent (LDI) amount, HAP content and surface modification of HAP on the LVE properties of the composites was determined based on the analysis of the master curves of storage (G') and loss (G″) moduli and of tanδ of the composites. Depending on the amount of LDI, HAP and surface modification, the materials differ in the values of rubber elasticity plateau modulus (G0) and G' and G″ determined at selected shear frequencies and at the glassy state. G0 ranges from 278 kPa to 3.98 MPa, G' in the glassy state is within the range of 219 MPa-459 MPa. The G0 values of the PGAU-based composites are within the stiffness range of soft tissue. In view of the choice of HAP as the ceramic component and the G0 values, elastomeric composites have the potential to be used as filling materials in small bone defects (due to their mechanical similarity to osteoid) as well as materials for cartilage tissue regeneration.

Degradable biomedical elastomers: paving the future of tissue repair and regenerative medicine

Degradable biomedical elastomers (DBE), characterized by controlled biodegradability, excellent biocompatibility, tailored elasticity, and favorable network design and processability, have become indispensable in tissue repair. This review critically examines the recent advances of biodegradable elastomers for tissue repair, focusing mainly on degradation mechanisms and evaluation, synthesis and crosslinking methods, microstructure design, processing techniques, and tissue repair applications. The review explores the material composition and cross-linking methods of elastomers used in tissue repair, addressing chemistry-related challenges and structural design considerations. In addition, this review focuses on the processing methods of two- and three-dimensional structures of elastomers, and systematically discusses the contribution of processing methods such as solvent casting, electrostatic spinning, and three-/four-dimensional printing of DBE. Furthermore, we describe recent advances in tissue repair using DBE, and include advances achieved in regenerating different tissues, including nerves, tendons, muscle, cardiac, and bone, highlighting their efficacy and versatility. The review concludes by discussing the current challenges in material selection, biodegradation, bioactivation, and manufacturing in tissue repair, and suggests future research directions. This concise yet comprehensive analysis aims to provide valuable insights and technical guidance for advances in DBE for tissue engineering.

Layer-by-layer assembly of poly-l-lysine/hyaluronic acid protein reservoirs on poly(glycerol sebacate) surfaces

The modification of biomaterial surfaces has become increasingly relevant in the context of ongoing advancements in tissue engineering applications and the development of tissue-mimicking polymer materials. In this study, we investigated the layer-by-layer (LbL) deposition of polyelectrolyte multilayer protein reservoirs consisting of poly-l-lysine (PLL) and hyaluronic acid (HA) on the hydrophobic surface of poly(glycerol sebacate) (PGS) elastomer. Using the methods of isothermal titration calorimetry and surface plasmon resonance, we systematically investigated the interactions between the polyelectrolytes and evaluated the deposition process in real time, providing insight into the phenomena associated with film assembly. PLL/HA LbL films deposited on PGS showed an exceptional ability to incorporate bone morphogenetic protein-2 (BMP-2) compared to other growth factors tested, thus highlighting the potential of PLL/HA LbL films for osteoregenerative applications. The concentration of HA solution used for film assembly did not affect the thickness and topography of the (PLL/HA)10 films, but had a notable impact on the hydrophilicity of the PGS surface and the BMP-2 release kinetics. The release kinetics were successfully described using the Weibull model and hyperbolic tangent function, underscoring the potential of these less frequently used models to compare the protein release from LbL protein reservoirs.

Harnessing the power of polyol-based polyesters for biomedical innovations: synthesis, properties, and biodegradation

Polyesters based on polyols have emerged as promising biomaterials for various biomedical applications, such as tissue engineering, drug delivery systems, and regenerative medicine, due to their biocompatibility, biodegradability, and versatile physicochemical properties. This review article provides an overview of the synthesis methods, performance, and biodegradation mechanisms of polyol-based polyesters, highlighting their potential for use in a wide range of biomedical applications. The synthesis techniques, such as simple polycondensation and enzymatic polymerization, allow for the fine-tuning of polyester structure and molecular weight, thereby enabling the tailoring of material properties to specific application requirements. The physicochemical properties of polyol-based polyesters, such as hydrophilicity, crystallinity, and mechanical properties, can be altered by incorporating different polyols. The article highlights the influence of various factors, such as molecular weight, crosslinking density, and degradation medium, on the biodegradation behavior of these materials, and the importance of understanding these factors for controlling degradation rates. Future research directions include the development of novel polyesters with improved properties, optimization of degradation rates, and exploration of advanced processing techniques for fabricating scaffolds and drug delivery systems. Overall, polyol-based polyesters hold significant potential in the field of biomedical applications, paving the way for groundbreaking advancements and innovative solutions that could revolutionize patient care and treatment outcomes.

Co-delivery of an HIV prophylactic and contraceptive using PGSU as a long-acting multipurpose prevention technology

OBJECTIVES

Poly(glycerol sebacate) urethane (PGSU) elastomers formulated with 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA), levonorgestrel (LNG), or a combination thereof can function as multipurpose prevention technology implants for prophylaxis against HIV and unintended pregnancies. For these public health challenges, long-acting drug delivery technologies may improve patient experience and adherence. Traditional polymers encounter challenges delivering multiple drugs with dissimilar physiochemical properties. PGSU offers an alternative option that successfully delivers hydrophilic EFdA alongside hydrophobic LNG.

METHODS

This article presents the formulation, design, and characterization of PGSU implants, highlighting the impact of API loading, dimensions, and individual- versus combination-loading on release rates.

RESULTS

Co-delivery of hydrophilic EFdA alongside hydrophobic LNG acted as a porogen to accelerate LNG release. Increasing the surface area of LNG-only implants increased LNG release. All EFdA-LNG, EFdA-only, and LNG-only formulated implants demonstrated low burst release and linear release kinetics over 245 or 122 days studied to date.

CONCLUSION

PGSU co-delivers two APIs for HIV prevention and contraception at therapeutically relevant concentrations in vitro from a single bioresorbable, elastomeric implant. A new long-acting polymer technology, PGSU demonstrates linear-release kinetics, dual delivery of APIs with disparate physiochemical properties, and biocompatibility through long-term subcutaneous implantation. PGSU can potentially meet the demands of complex MPT or fixed-dose combination products, where better solutions can serve and empower patients.

Potential Biological Properties of Lycopene in a Self-Emulsifying Drug Delivery System

In recent years, lycopene has been highlighted due to its antioxidant and anti-inflammatory properties, associated with a beneficial effect on human health. The aim of this study was to advance the studies of antioxidant and anti-inflammatory mechanisms on human keratinocytes cells (HaCaT) of a self-emulsifying drug delivery system (SEDDS) loaded with lycopene purified from red guava (nanoLPG). The characteristics of nanoLPG were a hydrodynamic diameter of 205 nm, a polydispersity index of 0.21 and a zeta potential of -20.57, providing physical stability for the nanosystem. NanoLPG demonstrated antioxidant capacity, as shown using the ORAC methodology, and prevented DNA degradation (DNA agarose). Proinflammatory activity was evaluated by quantifying the cytokines TNF-α, IL-6 and IL-8, with only IL-8 showing a significant increase (p < 0.0001). NanoLPG showed greater inhibition of the tyrosinase and elastase enzymes, involved in the skin aging process, compared to purified lycopene (LPG). In vitro treatment for 24 h with 5.0 µg/mL of nanoLPG did not affect the viability of HaCaT cells. The ultrastructure of HaCaT cells demonstrated the maintenance of morphology. This contrasts with endoplasmic reticulum stresses and autophagic vacuoles when treated with LPG after stimulation or not with LPS. Therefore, the use of lycopene in a nanoemulsion may be beneficial in strategies and products associated with skin health.

Introducing photo-crosslinked bio-nanocomposites based on polyvinylidene fluoride/poly(glycerol azelaic acid)-g-glycidyl methacrylate for bone tissue engineering

As a glycerol-based polyester, poly(glycerol azelaic acid) (PGAz) has shown great potential for biomedical applications, such as tissue engineering. However, it tends to show low mechanical strength and a relatively fast biodegradation rate, limiting its capability of mimicking and supporting a broad range of hard tissues such as bone. Moreover, the typical thermal curing process of poly(glycerol-co-diacids) is one of their drawbacks. To overcome these limitations, glycidyl methacrylate (GMA) moieties were first grafted on the backbone of PGAz herein to achieve a UV-curable PGAz-g-GMA (PGAG) resin. Then polyvinylidene fluoride (PVDF), nano-hydroxyapatite, and Cloisite Na⁺ nanoclay were used to fabricate photo-crosslinked PGAG/PVDF nanocomposites with efficient properties to mimic various hard tissues. Our results demonstrated that all nanocomposites possessed a semi-crystalline structure with noticeable PVDF β-phase fraction. The scaffolds yielded Young's modulus, ultimate tensile strength, and elongation at break of 15-24 MPa, 13-15 MPa, and 50-65%, respectively that could meet the requirements for supporting cancellous bone tissue. The presence of nanofillers improved the hydrophilicity and slightly accelerated the biodegradation rate of the scaffolds. Additionally, it was illustrated that the scaffolds had no noticeable in vitro cytotoxicity, and mouse fibroblast L929 cells and osteoblast MG-63 cells attached to and proliferated on their surface desirably. Our findings indicate that the PGAG/PVDF blend and its nanocomposites could be high-potential candidates for a range of hard tissues, specifically cancellous bones.

Preparation and characterization of a new sustainable bio-based elastomer nanocomposites containing poly(glycerol sebacate citrate)/chitosan/n-hydroxyapatite for promising tissue engineering applications

Poly (glycerol sebacate citrate) (PGSC) has potential applications in tissue engineering due to its biodegradability and suitable elasticity. However, its applications are restricted owing to its acidity and high degradation rate. In this study, a new bio-nanocomposite based on PGSC has been synthesized by incorporating chitosan (CS) and various concentrations of hydroxyapatite nanoparticles (n-HA). It is assumed that the basicity of a CS and hydroxyl groups of n-HA will reduce the acidity of PGSC and control the rate of degradation. Also, the biocompatibility of n-HA and inherent hydrophilicity of CS can improve cell adhesion and proliferation of PGSC-based scaffolds. FTIR, XRD, FESEM, and EDX tests confirmed the synthesis of these nanocomposites and the interaction between each of the components. The results of the DMTA test also indicated the elastic behavior of the samples embedded with n-HA. The hydrophilicity assay demonstrated that the water contact angle of the scaffolds decreased as the concentration of n-HA augmented, and it reached the value of 44 ± 0.9° for nanocomposite containing 5 wt.% n-HA. The degradation rate of all PGSC nanocomposites was reduced due to the anionic groups of n-HA and CS. TGA assay indicated that the incorporation of n-HA led to the enhancement of scaffolds' thermal stability. Furthermore, the synergistic effect of CS and n-HA on the enhancement of protein adsorption and cell proliferation was confirmed through protein adhesion and MTT assay, respectively. Consequently, the addition of n-HA and CS perform the new bio-nanocomposites scaffolds based on PGSC with sufficient hydrophilicity, flexibility, and thermal stability in tissue engineering applications.

Preparation and characterization of a new bio nanocomposites based poly(glycerol sebacic-urethane) containing nano-clay (Cloisite Na+ ) and its potential application for tissue engineering

Nanocomposites containing clay nanoparticles often present favorable properties such as good mechanical and thermal properties. They frequently have been studied for tissue engineering (TE) and regenerative medicine applications. On the other hand, poly(glycerol sebacate) (PGS), a revolutionary bioelastomer, has exhibited substantial potential as a promising candidate for biomedical application. Here, we present a facile approach to synthesizing stiff, elastomeric nanocomposites from sodium-montmorillonite nano-clay (MMT) in the commercial name of Cloisite Na⁺ and poly(glycerol sebacate urethane) (PGSU). The strong physical interaction between the intercalated Cloisite Na⁺ platelets and PGSU chains resulted in desirable property combinations for TE application to follow. The addition of 5% MMT nano-clay resulted in an over two-fold increase in the tensile modulus, increased the onset thermal decomposition temperature of PGSU matrix by 18°C, and noticeably improved storage modulus of the prepared scaffolds, compared with pure PGSU. As well, Cloisite Na⁺ enhanced the hydrophilicity and water uptake ability of the samples and accelerated the in-vitro biodegradation rate. Finally, in-vitro cell viability assay using L929 mouse fibroblast cells indicated that incorporating Cloisite Na⁺ nanoparticles into the PGSU network could improve the cell attachment and proliferation, rendering the synthesized bioelastomers potentially suitable for TE and regenerative medicine applications.