Search Results (181)

Gel-based novel drug delivery systems (NDDS) occupy a mechanistically distinct niche among controlled-release platforms because they decouple three design variablesnetwork cross-link density, continuous-phase polarity, and stimulus sensitivitythat in particulate carriers (liposomes, polymeric nanoparticles) are often interdependent. This critical review synthesizes 102 primary and secondary sources published predominantly between 2010 and 2026 to interrogate, rather than merely catalog, how hydrogels, organogels, aerogels, nanogels, in situ gelling systems, and hydrogel-forming microneedles have been engineered for site-specific pharmacotherapy. Beyond a taxonomic overview, the review quantitatively contrasts formulation parameters sol–gel transition temperatures (typically 32–37 °C for poloxamer 407/188 systems), swelling ratios, mesh sizes, and reported drug-release half-lives across oncology, chronic diabetic wound care, ophthalmic and nasal-to-brain delivery, musculoskeletal (intra-articular) therapy, subunit vaccine depots, periodontal pocket therapy, and glucose-responsive insulin delivery. Particular attention is paid to the mechanistic basis of burst release, the porosity–mechanical-integrity trade-off inherent to interconnected hydrogel networks, and the divergence between preclinical rodent efficacy and the comparatively sparse controlled human trial data available for most gel platforms. The review concludes that while stimuli-responsive and 3D/4D-printed gel architectures have matured substantially as engineering constructs, clinical translation remains bottlenecked less by materials science than by inconsistent characterization standards, unresolved terminal-sterilization compatibility, and a paucity of head-to-head comparative trials against existing standard-of-care formulations. Full article

Liquid water in hydrogels exhibits an adsorption-desorption dynamic equilibrium with the surrounding environment, which leads to the instability of mechanical properties. To address this limitation, we propose an innovative design of conductive composite organogels by incorporating compatible linear lauryl alcohol (LA) and multi-walled carbon nanotubes (CNTs) into a poly(butyl methacrylate) (PBMA) network. Carbon chains of LAform physical crosslinks with PBMA side chains, effectively replacing inherent polymer chain entanglements. This structural innovation facilitates rapid chain rotation and sliding during stretching, so that the gel has a super stretching property of up to 2460%. At elevated temperatures, weakened interactions between LA–PBMA and PBMA–PBMA chains reduce physical confinement of CNTs within the PBMA network. Simultaneously applying a directional electric field, CNTs undergo rotation and translation to reconstruct an optimized conductive pathway, granting the composite distinctive temperature-sensitive electrical conductivity. Critically, all components in the PBMA/LA/CNTs (PLCs) exhibit low volatility and hydrophobicity. These characteristics enable the organogel to retain excellent flexibility and stable electrical performance after prolonged immersion in deionized water, exposure to vacuum, and even under extreme conditions at 120 °C. Such comprehensive stability suggests promising applications in deep-sea exploration and aerospace engineering. Full article

The growing demand for sustainable, natural-based polymeric materials has accelerated research into cellulose-derived gels. Ethyl cellulose (EC) is a promising candidate; however, its high brittleness, limited flexibility, and insufficient water barrier properties often require the use of a plasticizer to improve its performance. In this study, we synthesized hydroxylated linseed oil polyol (LPO) and evaluated its performance as a bio-based plasticizer for EC-derived dried gels. LPO was characterized by ¹H NMR, ¹³C NMR and FTIR. In addition, quantitative tests further confirmed high hydroxyl value of 280.36 ± 28.96 mg KOH/g. Incorporating LPO into the EC organogel matrix improved the functional performance of dried gel composites, including their mechanical, water vapor barrier, thermal, and morphological properties. The greatest plasticizing performance was achieved at the highest concentration investigated (30% w/w), with a fivefold increase in elongation at break compared to the pristine EC, together with the lowest WVP value (~13 g·mm·m⁻²·kPa⁻¹·day⁻¹), while maintaining good thermal stability and a smooth, homogeneous surface morphology. In addition, FTIR, SEM, and accelerated aging analyses supported the good compatibility and stability of the EC/LPO system. These effects are attributed to intermolecular interactions between EC chains and LPO. Overall, LPO is demonstrated to be an effective bio-based plasticizer for advancing sustainable bioplastic materials, highlighting its potential to replace conventional plasticizers. Full article

Traumatic brain injury (TBI) presents a mechanically sensitive and pharmacologically complex environment in which therapeutic delivery remains challenging. Bigels may offer a formulation strategy for incorporating therapeutics with differing physicochemical properties while providing soft, viscoelastic matrices with properties that may be relevant to neural delivery applications. This study evaluated the in vitro formulation feasibility of a biphasic stearate organogel–methylcellulose/gelatin bigel as a mechanically compliant biphasic vehicle for localized delivery of neurotherapeutic agents. Bigels were fabricated by hot emulsification and genipin crosslinking to generate hydrogel-dominant dual-phase systems. Hydrogel:organogel formulations of 95:5 (BG1) and 85:15 (BG2) showed storage moduli of approximately 250 Pa and 200 Pa, respectively, and compressive Young’s moduli of 0.39 and 0.70 kPa, within reported ranges for soft brain tissue. Stress relaxation confirmed viscoelastic behaviour, while minimal oil leakage (<0.2%) indicated phase stability. BG1 showed 52% porosity, pore sizes of 1.8–22 µm, and approximately 14% weight gain. Drug release followed Weibull kinetics (R² = 0.99–0.999), with nicotinamide showing faster release and N-acetylcysteine and TPGS showing more sustained release. Both unloaded and drug-loaded bigels maintained >70% PC12 cell viability. These findings support the formulation feasibility of biphasic bigels as mechanically compliant vehicles capable of accommodating therapeutics with differing physicochemical properties and exhibiting differential release behaviour. Further studies are required to evaluate degradation, tissue interactions, retention, and therapeutic performance in advanced in vitro and in vivo models. Full article

The demand for eco-friendly viscosity modifiers in food, cosmetics, and lubricants has increased, promoting the development of high-performance, sustainable materials. Low-molecular-weight gelators (LMWGs) are promising candidates, though their behavior in complex systems remains underexplored. In this study, a novel alkylamido isophthalic acid-based LMWG (AIPA–gallic acid) was synthesized. Its performance was evaluated in vegetable oil, mineral oil, and cocoa butter using rheological measurements across varying concentrations and temperatures, with all dynamic rheological measurements conducted in the viscoelastic region. Cacao butter is solid at 15 °C, so the flow curve that can be obtained at this temperature should show high values not comparable with the other liquid oils. No slippage phenomenon was observed. Using a step-rate protocol before acquiring the flow curves, no time-dependent behavior (thixotropy) was observed. Frequency and flow sweep tests were used to assess viscoelastic properties, interaction strength, and coordination number. Results revealed that incorporating AIPA–gallic acid at 4 wt% increased the viscosity by 74 times (at 25 °C) in mineral oil, compared to an increase of about four orders of magnitude in vegetable oil. This suggests the formation of intermolecular interactions that lead to an increased momentum transport process, which is significantly higher in vegetable oil. In contrast, cocoa butter exhibited minimal rheological changes, suggesting that no gelation occurred. Analysis using the weak gel model confirmed that viscosity enhancement arises from a structured network in mineral and vegetable oils, but not in cocoa butter. Temperature-dependent variations in structural parameters further highlight the role of molecular interactions between the gelator and the oil matrix. Full article

Flexible and wearable electronics require soft sensing materials that balance mechanical compliance, stable signal transduction, and durability for human–machine interfaces (HMIs). To address the limitations of single-filler systems, we propose a poly(vinyl alcohol) (PVA)/aramid nanofiber (ANF)/MXene organogel (PAM) as a multifunctional soft platform. This design integrates a PVA physically crosslinked network with ANF for mechanical reinforcement and MXene for electrical functionality. The optimized PAM composite exhibits outstanding mechanical properties, including a fracture stress of 2931 kPa, a fracture strain of 676%, and a fracture toughness of 9.04 MJ m⁻³. Importantly, PAM serves as a single material platform configurable into three sensing modalities. The resistive strain sensor achieves a gauge factor of 3.1 over 10–100% strain and enables the reliable recognition of human joint movements and gestures. The capacitive pressure sensor delivers a sensitivity of 0.298 kPa⁻¹, rapid response/recovery times of 30/10 ms, and is integrated with a wireless module to control a smart car. Furthermore, the PAM-based triboelectric nanogenerator (TENG) delivers excellent electrical outputs (V_oc = 123 V, I_sc = 0.52 μA, Q_sc = 58 nC) and functions as a self-powered smart handwriting pad, achieving a machine-learning-based recognition accuracy of 97.6%. This work demonstrates the immense potential of the PAM organogel for advanced, self-powered HMIs. Full article

Nitric oxide (NO) is a gaseous biocompatible radical molecule with demonstrated biomedical and antimicrobial benefits. Developing adaptable, long-lasting delivery systems for NO has become an essential goal for both combating resistant bacterial growth and providing sustained medical benefits. Silsesquioxane (SQ)-based organogels were chosen and synthesized as robust, tunable NO-release platforms. These highly stable SQ gel frameworks, composed of silicon–oxygen backbones with variable R groups, exhibited high porosity and surface area and offered chemical versatility, enabling control over NO loading and release. 3-Mercaptopropyl groups were utilized as sulfur-based NO-releasing substituents (-RSNOs), with additional R groups capable of altering accessibility to RSNO sites through hydrophobicity and steric hindrance. The NO release profile, rate, and duration of the functionalized gels were also tailored by adjusting the number of RSNO sites in the elastomeric system, thereby enabling a customizable release profile. This combination of NO-releasing silsesquioxanes with silicone elastomers yields composite materials that are integratable into biomedical applications, offering NO release up to 40 days within modeled physiological conditions in PBS buffer. Full article

The development of new advanced functional materials from low-molecular-weight gelators and their new potential applications have occupied a considerable place in research. The present study involves the design of dipeptide-based organogelators with enhanced hydrogen bonding network potentials and phase-selective capacities, possessing a minimum gelation concentration of 0.2–0.4% w/v in different fluids. Seven new dipeptide organogelators were prepared based on a one-step reaction from two-component salt forms, the combination of Nε-alkanoyl-L-lysine ethyl ester with N-alkanoyl-L-amino acids (L-alanine, L-leucine, and L-phenylalanine), with high yields of up to 90. All the gel materials were extremely stable at room temperature, having a shelf life of several months, and formed gels in pharmaceutical fluids such as ethyl palmitate, ethyl myristate, and ethyl laurate, 1,2-propanediol, and liquid paraffin (oils widely used in pharmaceutical formulations), which meet the criteria of biological materials delivery. Their gelation properties were evaluated by rheological measurements. A very significant breakthrough in the current study is that organogels remove the toxic dye, crystal violet (CV), from water in a phase-selective manner with an extremely low gelator concentration. The dye and gelators are successively recovered via ethanol precipitation after the completion of the phase extraction process. Molecular dynamic calculations provide evidence for the 3D structures of the gels. Full article

Deep eutectic solvent (DES), when used as the continuous phase of eutectogels, can significantly improve their electrical and mechanical properties due to its excellent conductivity, freeze resistance and chemical stability. The development of eutectogels effectively solves the key limitations of traditional hydrogels and organogels, such as low-temperature freezing, high-temperature volatilization, and organic solvent leakage. It also realizes the collaborative optimization of environmental friendliness and comprehensive performance, which makes it show broad application prospects in the field of flexible sensing. This review summarizes the design principles, material selection, sensing mechanisms, and flexible sensing applications of eutectogels. By examining the design of eutectogels, the selection of DES, and the synthesis of the gel network, it provides a theoretical basis for the development of eutectogel-based sensor devices. A detailed description of the sensing mechanism is provided to elucidate the signal generation and transition in eutectogels toward the purpose of the practical applications. Finally, the application prospects of eutectogels for high-performance sensors and detection devices are discussed. Additionally, we provide a theoretical support for their structural design, performance optimization, and practical application. Full article

Background: Diabetes mellitus is common and associated with numerous complications including diabetic foot ulcers (DFU), which affect a third of patients and are associated with high morbidity and mortality. There are limited pharmacologic treatment options available with mixed efficacy. We have developed a novel therapeutic targeting inflammation and oxidative stress by conjugating microRNA-146a to cerium oxide nanoparticles to create CNP-miR146a and have found that injectable CNP-miR146a is associated with improved wound healing in a diabetic murine model. We hypothesized that a topical formulation of CNP-miR146a would be associated with equivalent improvements in wound healing. Methods: Release tests of CNP conjugated to fluorescein isothiocyanate were performed to determine the optimal gel base for sustained release. Diabetic (db/db) mice were cutaneously wounded and treated with topical CNP-miR146a, empty gel, injectable CNP-miR146a, or injectable phosphate-buffered saline (PBS). Wound healing over time was compared between groups. Histological samples were collected and analyzed for CD45 and CD31 positivity at multiple timepoints. Results: CNP-miR146a in a topical pluronic lecithin organogel (PLO) base was associated with significantly improved wound healing compared to empty gel or injected PBS and equivalent to injected CNP-miR146a. Treatment with CNP-miR146a was also associated with decreased CD45 positivity and increased CD31 positivity, suggesting decreased inflammation and improved angiogenesis. Conclusions: Topical delivery of CNP-miR46a in a PLO base holds significant promise as a potential therapeutic for DFU and may improve patient compliance due to ease of delivery. Full article

With the rapid development of artificial intelligence and wearable electronics, there is an increasing demand for skin-like, flexible, and self-powered sensors capable of continuously perceiving mechanical stimuli and human motions. Triboelectric nanogenerator (TENG)-based sensors incorporating stretchable conductive gels represent a promising approach to meet these requirements by combining soft mechanical compliance with efficient electromechanical signal transduction. However, conventional metallic or composite electrodes often suffer from mechanical mismatch with soft skin-like systems, motivating the exploration of intrinsically soft and stretchable conductive gels. In this review, we present a comprehensive and structured overview with comparative perspectives of stretchable skin-like conductive gel-based triboelectric devices. First, different classes of conductive gels, including hydrogels, organogels, ionogels, and other emerging gel systems, are systematically summarized and compared in terms of their composition, crosslinking strategies, conductivity, and mechanical characteristics. Next, the pivotal role of conductive gels in bridging skin-like sensing functions and triboelectric applications is elucidated, highlighting how their intrinsic softness, stretchability, self-healing capability, and interfacial conformability enable intimate skin contact and reliable electromechanical coupling. The key performance attributes of gel-based skin-like triboelectric sensors, including stretchability, self-healing behavior, optical and thermal tolerance, electrical durability, and environmental stability, are critically discussed with representative examples and comparative analysis. Typical device configurations, such as thin-film, fiber-shaped, and textile-based architectures, are further reviewed to illustrate structure–function relationships and application-oriented design strategies. Finally, current challenges, limitations, and future research directions for stretchable conductive gel-based triboelectric systems are outlined, aiming to provide practical guidelines and insights for the rational design of high-performance skin-like triboelectric sensors based on conductive gels. Full article

Sugar fatty acid esters represent promising scaffolds for technological applications. These compounds are low-cost and allow rapid modulation of their properties. In this study, we have shown that lipase obtained from solid fermentation from Aspergillus niger (hydrolytic activity of 8.32 × 10⁶ U/g) can promote a selective route towards the 2,5-dissubstituted D-mannitol laurate. Indeed, the lipase hydrolytic activity allowed the yield of 80% in DMF (P.A.) at 55 °C and 6 h. Finally, Mg/Al layered double hydroxides (LDH) were compared towards the selectivity of the expected dissubstituted product. The data obtained through the comparative analysis allows establishing some variables such as solvent (DMF), temperature (55 °C) and solvent dehydration degree for obtaining these molecules for future application studies in supramolecular gelation systems. Full article

Metallogels constitute a rapidly expanding class of hybrid soft materials in which metal ions, metal complexes, or metal-containing nanoparticles play a decisive structural and functional role within a three-dimensional gel network. Their unique combination of supramolecular assembly, metal-ligand coordination, and dynamic network behaviour provides tunable mechanical, optical, electrical, redox, and catalytic properties that are not accessible in conventional hydrogels or organogels. This review systematically summarises current knowledge on metallogels, beginning with a classification based on matrix type, dominant metal interaction and functional output, spanning metallohydrogels, metal-organic gels, metal-phenolic gels, nanoparticle-based gels, polymer-based metallogels and low-molecular-weight metallogels. Key synthesis pathways are discussed, including coordination-chemistry-driven formation, metal-ligand self-assembly, in situ reduction, diffusion-mediated strategies, sol-gel-like polymerisation, enzyme-assisted routes, and bio-derived fabrication. Particular emphasis is placed on structure-function relationships that enable the development of catalytic, conductive, luminescent, antimicrobial, and biomedical metallogels. The examples compiled here highlight the versatility and transformative potential of metallogels in next-generation soft technologies, including sensing, energy conversion, wound healing, drug delivery, and emerging applications such as soft electronics and on-skin catalytic or bioactive patches. By mapping current progress and emerging design principles, this review aims to support the rational engineering of metallogels for advanced technological and biomedical applications Full article

(1) Background: Gastroretentive systems are an interesting option for enhancing the bioavailability of weak bases and poorly soluble drugs. The aim of this study was to formulate supramolecular organogels based on cinnarizine (CIN) as a potential gastroretentive system. (2) Methods: The organogels were prepared with different oils in different ratios. Thereafter, their pharmaceutical characteristics and in vitro gastric retention were evaluated through in vitro and in silico simulations. (3) Results: Organogels with different proportions of CIN to oils were successfully obtained. The DSC thermal analysis results demonstrated that all organogels showed gel–sol temperature transitions. The frequency sweep test verified that all organogels presented frequency-independent behavior. Optical imaging revealed longitudinal spherulites of the 1:4 CIN in organogels in all oils. The CIN organogels in all oils (1:4) were observed to float in gastric media during the entire release study. The pharmacokinetic parameters of CIN in peppermint oil (1:4) revealed a close Cmax value to that of the 25 mg immediate-release tablet, but a different AUC. (4) Conclusions: The organogels in all oils floated throughout the release study, establishing their potential as a gastroretentive system. Furthermore, these dosage forms were assessed as a gastric-controlled system through in silico simulations, which enabled prediction of their pharmacokinetic parameters. Full article

Gel-based depots are increasingly recognized as platforms to extend the intratissue residence of local anesthetics (LAs) while reducing systemic exposure. Hydrogels, organogels, and emerging bigels represent three distinct architectures defined by their continuous phases and drug–matrix interactions. Hydrogels provide hydrated polymer networks with predictable injectability, tunable degradation, and diffusion- or stimulus-responsive release, enabling sustained analgesia in perineural, peri-incisional, intra-articular, and implant-adjacent settings. Organogels, formed by supramolecular assembly of low-molecular-weight gelators in lipids or semi-polar solvents, strongly solubilize lipophilic LA bases and enhance barrier partitioning, making them suitable for dermal, transdermal, and mucosal applications in outpatient or chronic pain care. Bigels integrate aqueous and lipid domains within biphasic matrices, improving rheology, spreadability, and dual-solubilization capacity, although their use in LA delivery remains at the formulation stage, with no validated in vivo pharmacology. This narrative review synthesizes the design principles, release mechanisms, and translational evidence across these platforms, highlighting domain-specific advantages and barriers related to mechanical robustness, sterilization, reproducibility, and regulatory feasibility. We propose a platform-level framework in which depot selection is aligned with LA chemistry, anatomical context, and clinical objectives to guide the development of workflow-compatible next-generation LA depots. Full article