Search Results (572)

Intratumoral injections of macromolecules, such as biologics and immunotherapeutics, show promise in overcoming dose-limiting side effects associated with systemic injections and improve treatment efficacy. However, the retention of injectates in the tumor microenvironment is a major underappreciated challenge. High interstitial pressures and dense tumor architectures create shear forces that rapidly expel low-viscosity solutions post-injection. Injectable hydrogels may address these concerns by providing a viscoelastic delivery vehicle that shields loaded therapies from rapid expulsion from the tumor. A chitosan–glycerol hydrogel was thus developed and characterized with the goal of improving the injection retention of loaded therapeutics. The gelation parameters and mechanical properties of the hydrogel were explored to reveal a shear-thinning gel that is injectable through a 27-gauge needle. Biocompatibility studies demonstrated that the chitosan–glycerol hydrogel was nontoxic. Retention studies revealed significant improvements in the retention of model therapeutics when formulated with the chitosan–glycerol hydrogel compared to less-viscous solutions. Finally, release studies showed that there was a sustained release of model therapeutics of various molecular sizes from the hydrogel. Overall, the chitosan–glycerol hydrogel demonstrated injectability, enhanced retention, biocompatibility, and sustained release of macromolecules, indicating its potential for future clinical use in intratumoral macromolecule delivery. Full article

Background: Oral lichen planus is a chronic, potentially malignant disorder affecting the mucous membrane. As the etiology remains not fully understood, the treatment of this condition is mainly symptomatic, involving corticosteroids and other immunosuppressive agents, e.g., calcineurin inhibitors. One of the alternative therapeutic approaches includes platelet concentrates, which are autologous bioactive materials. The aim of this review was to evaluate the effects of platelet concentrates in the treatment of oral lichen planus and to compare them to other therapeutic strategies. Methods: The electronic databases PubMed/Medline, Web of Science, and Cochrane Library were searched for articles published up to 30 March 2025, describing clinical studies focused on oral lichen planus and treatment with platelet concentrates. Results: Fourteen studies describing the effects of oral lichen planus therapy with three types of platelet concentrates (injectable platelet-rich plasma, injectable platelet-rich fibrin, and platelet-rich plasma gel) were included in this review. Comparative strategies included steroids and immunosuppressive agents. The treatment duration ranged from 3 weeks to 2 months. The follow-up period varied from 4 weeks to 6 months. In most of the studies, comparable efficacy was achieved for platelet derivatives and alternative treatments. Two of the studies demonstrated more beneficial effects for platelet concentrates compared to controls, while in one of the studies, more severe adverse reactions were revealed in the platelet group compared to the controls. Conclusions: Autologous platelet concentrates showed comparable efficacy in achieving clinical improvement in patients with oral lichen planus to steroids and immunosuppressive drugs. Platelet derivatives could be considered as an alternative treatment to topical immunosuppressives, especially in steroid-refractory cases. Full article

Channeling in cementing causes interlayer interference, severely restricting oilfield recovery. Existing channeling plugging agents, such as cement and gels, often lead to reservoir damage or insufficient strength. Oil-soluble resin (OSR) particles show great potential in selective plugging of channeling fractures due to their excellent oil solubility, temperature/salt resistance, and high strength. However, their application is limited by the efficient filling and retention in deep fractures. This study innovatively combines the OSR particle plugging system with the mature rapid filtration loss plugging mechanism in drilling, systematically exploring the influence of particle size and sorting on their filtration, packing behavior, and plugging performance in channeling fractures. Through API filtration tests, visual fracture models, and high-temperature/high-pressure (100 °C, salinity 3.0 × 10⁵ mg/L) core flow experiments, it was found that well-sorted large particles preferentially bridge in fractures to form a high-porosity filter cake, enabling rapid water filtration from the resin plugging agent. This promotes efficient accumulation of OSR particles to form a long filter cake slug with a water content <20% while minimizing the invasion of fine particles into matrix pores. The slug thermally coalesces and solidifies into an integral body at reservoir temperature, achieving a plugging strength of 5–6 MPa for fractures. In contrast, poorly sorted particles or undersized particles form filter cakes with low porosity, resulting in slow water filtration, high water content (>50%) in the filter cake, insufficient fracture filling, and significantly reduced plugging strength (<1 MPa). Finally, a double-slug strategy is adopted: small-sized OSR for temporary plugging of the oil layer injection face combined with well-sorted large-sized OSR for main plugging of channeling fractures. This strategy achieves fluid diversion under low injection pressure (0.9 MPa), effectively protects reservoir permeability (recovery rate > 95% after backflow), and establishes high-strength selective plugging. This study clarifies the core role of particle size and sorting in regulating the OSR plugging effect based on rapid filtration loss, providing key insights for developing low-damage, high-performance channeling plugging agents and scientific gradation of particle-based plugging agents. Full article

Thermosensitive hydrogels undergo reversible sol-gel phase transitions in response to changes in temperature. Owing to their excellent biocompatibility, mild reaction conditions, and controllable gelation properties, these hydrogels represent a promising class of biomaterials suitable for minimally invasive treatment systems in diverse biomedical applications. This review systematically summarizes the gelation mechanisms of thermosensitive hydrogels and optimization strategies to enhance their performance for broader application requirements. In particular, we highlight recent advances in injectable thermosensitive hydrogels as a carrier within stem cells, bioactive substances, and drug delivery for treating various tissue defects and diseases involving bone, cartilage, and other tissues. Furthermore, we propose challenges and directions for the future development of thermosensitive hydrogels. These insights provide new ideas for researchers to explore novel thermosensitive hydrogels for tissue repair and disease treatment. Full article

Postoperative adhesions are a prevalent complication following abdominal surgeries, often leading to significant clinical challenges. This study introduces an innovative solution utilizing a polyethylene glycol (PEG)-based triblock copolymer to form an injectable, self-healing hydrogel aimed at preventing these adhesions. The hydrogel, formulated with temperature-responsive and self-healing properties through the incorporation of poly (N-isopropyl acrylamide) (PNIPAM) and anion–pi interactions, was synthesized using reversible addition–fragmentation chain transfer (RAFT) polymerization. The hydrogel’s physical properties, biocompatibility, hemostatic effect, and anti-adhesive capabilities were rigorously tested through in vitro and in vivo experiments involving rat models. It demonstrated excellent biocompatibility, effective tissue adhesion, and robust hemostatic properties. Most notably, it exhibited significant anti-adhesive effects in a rat abdominal wall–cecum model, reducing adhesion formation effectively compared to controls. The PEG-based injectable hydrogel presents a promising approach for postoperative adhesion prevention. Its ability to gel in situ triggered by body heat, coupled with its self-healing properties, provides a substantial advantage in clinical settings, indicating its potential utility as a novel anti-adhesion material. Full article

To investigate the energy conduction behavior of polymer gel profile control and flooding in low-permeability reservoirs, a parallel dual-tube displacement experiment was conducted to simulate reservoirs with different permeability ratios. Injection schemes included constant rates from 0.40 to 1.20 mL/min and dynamic injection from 1.20 to 0.40 mL/min. Pressure monitoring and shunt analysis were used to evaluate profile control and recovery performance. The results show that polymer gel preferentially enters high-permeability layers, transmitting pressure more rapidly than in low-permeability zones. At 1.20 mL/min, pressure onset at 90 cm in the high-permeability layer occurs earlier than in the low-permeability layer. Higher injection rates accelerate pressure buildup. At 0.80 mL/min, permeability contrast is minimized, achieving a 22.96% recovery rate in low-permeability layers. The combination effect of 1.2–0.4 mL/min is the best in dynamic injection, with the difference in shunt ratio of 9.6% and the recovery rate of low permeability layer increased to 31.23%. Polymer gel improves oil recovery by blocking high-permeability channels, expanding the swept volume, and utilizing viscoelastic properties. Full article

In this study, we designed an injectable skin-rejuvenating formulation based on polyethylene glycol–polycaprolactone–polyethylene glycol (PEG-PCL-PEG) copolymers to provide a synergistic combination of biocompatibility, antioxidative capacity, and regenerative potential. Through the systematic optimization of the precursor molar ratio and molecular weight, well-defined PEG-PCL-PEG copolymers were synthesized and structurally characterized using gel permeation chromatography (GPC), proton nuclear magnetic resonance (¹H-NMR), and Fourier transform infrared (FT-IR) spectroscopy. An optimized precipitation and drying protocol effectively reduced residual solvents, as confirmed by gas chromatography (GC). Idebenone was incorporated as an antioxidant to prevent skin aging, while hyaluronic acid (HA), L-arginine, and glycerin were included to promote collagen regeneration. In vitro assays demonstrated that idebenone-loaded samples exhibited prolonged intracellular antioxidant activity with low cytotoxicity. The collagen-promoting formulation, containing HA, glycerin, and L-arginine, enhanced the expression of transforming growth factor-β (TGF-β) and type III collagen (COL3) while suppressing inflammatory genes, suggesting a favorable environment for extracellular matrix remodeling. In vivo evaluation corroborated these outcomes, showing angiogenesis, collagen reorganization, and progressive dermal thickness. Histological analysis further confirmed sustained matrix regeneration and tissue integration. These results highlight the potential of PEG-PCL-PEG-based injectables as a multifunctional platform for collagen regeneration, offering a promising strategy for both cosmetic and clinical applications. Full article

Due to its sarcoma-derived origin and the associated carcinogenic risks, as well as its lack of tissue-specific extracellular matrix biochemical cues, the use of the injectable gel scaffold Matrigel is generally restricted to research applications. Therefore, the development of new fully synthetic injectable gel scaffolds that exhibit performance comparable to Matrigel is a high priority. In this study, we developed a novel fully synthetic injectable gel scaffold by combining a biodegradable PLGA-PEG-PLGA copolymer, clay nanoparticle LAPONITE®, and L-arginine-loaded metal–organic frameworks (NU-1000) at the nano level. An aqueous solution of the developed hybrid scaffold (PLGA-PEG-PLGA/LAPONITE®/L-Arg@NU-1000) exhibited rapid sol–gel transition at body temperature following simple injection and formed a continuous bulk-sized gel, demonstrating good injectability. Long-term sustained slow release of L-arginine from the resultant gels can be achieved because NU-1000 is a suitable reservoir for L-arginine. PLGA-PEG-PLGA/LAPONITE®/L-Arg@NU-1000 hybrid gels exhibited good compatibility with and promoted the growth of human skeletal muscle satellite cells. Importantly, in vivo experiments using skeletal muscle injury model mice demonstrated that the tissue regeneration efficiency of PLGA-PEG-PLGA/LAPONITE®/L-Arg@NU-1000 gels is higher than that of Matrigel. Specifically, we judged the higher tissue regeneration efficacy of our gels by histological analysis, including MYH3 immunofluorescent staining, H&E staining, and Masson’s trichrome staining. Taken together, these data suggest that novel hybrid hydrogels could serve as injectable hydrogel scaffolds for in vivo tissue engineering and ultimately replace Matrigel. Full article

The recycling of plastics collected from household waste to produce post-consumer recycled (PCR) materials is a critical step of sustainable waste management. However, the processing of PCR materials presents unique challenges, particularly in the context of seasonal input stream fluctuations and resulting PCR material composition variations. Within this paper, the influence of batch-to-batch fluctuations on the processing stability and product properties of high-density polyethylene (HDPE) PCR from the German municipal waste system is analysed. It examines how variations in batch composition affect key parameters such as processing data (injection pressure, torque), mechanical properties (tensile strength, E-modulus, impact strength), and product quality (gel formation, part dimensions, part weight). Therefore, six consecutive household HDPE PCR material batches are analysed regarding their composition, contaminations, and rheological characteristics through ashing, differential scanning calorimetry, high-temperature gel permeation chromatography, and high-pressure capillary rheometry. The batches are then processed using blown- and cast-film extrusion as well as injection moulding, and the resulting process stability and product quality are analysed. The results show a strong correlation between thermal properties, such as crystallisation enthalpy, molecular weight, polypropylene (PP) content, varying batch viscosities, and changes in processing data as well as the resulting product properties. Full article

Background: Effective pain management in children is essential, particularly when administering local anaesthesia. This study was undertaken to compare pain perception in children after application of pre-cooled and plain topical anaesthetic gel during local anaesthetic administration. Methods: A randomised, single-blinded controlled trial was conducted among 51 children between the ages of 6 and 12, visiting the paediatric clinic, Jazan (REC-45/10/1070). Children were allocated into one of the following three groups using a simple randomisation having a 1:1:1 allocation ratio into Group I (n = 17): Plain topical anaesthetic gel, Group II (n = 17): Pre-Cooled topical anaesthetic gel, and Group III (n = 17). An ice pack was applied for a period of 1 min at the injection site. The intensity of pain and the behaviour of the children were assessed using Face, Leg, Activity, Cry, Consolability (FLACC), the Modified Wong–Baker Scale (WBS) and the Frankel Behaviour Rating Scale (FBRS). Results: A significant difference in FBRS scores was observed during anaesthesia, with the highest median score [3 (3,3)] in the pre-cooled topical anaesthetic gel group (p value < 0.001). FLACC scores varied significantly among groups, with the ice pack group [3 (3, 3)] and [4 (4, 5)] showing the highest median score (p value < 0.001). WBS scores also differed significantly between groups (p value < 0.001) with a lower value in the pre-cooled topical gel group [0 (0, 0), 2 (0, 2)]. Conclusions: This study concluded that, the use of a pre-cooled topical anaesthetic gel before LA administration reduced the pain better than that of plain anaesthetic gel and ice pack application at the injection site during infiltration. Full article

This study develops and characterizes GelMA–dopamine conjugates as novel tissue adhesives, offering an alternative to sutures. GelMA was synthesized at 5%, 10%, and 15% (w/v) with medium and high dopamine (DOPA) conjugation. Adhesives were evaluated for swelling, degradation, mechanical strength, and cytocompatibility using AlamarBlue assays and F-actin staining to assess cell viability and adhesion. Our findings indicate that DOPA conjugation significantly reduced the swelling ratio while increasing the biodegradation rate, resulting in enhanced release of free methacrylate groups over time. The mechanical properties and adhesion capabilities showed a complex relationship with DOPA substitution. Notably, the formulation containing 10% GelMA with high dopamine conjugation (HD) exhibited superior adhesion and mechanical strength. All formulations demonstrated shear-thinning behavior and recovery, making them suitable for injection and bioprinting applications. Although increased DOPA levels negatively affected crosslinking, the optimal formulation achieved a balance between adhesion and gel concentration. Rapid crosslinking was achieved within five minutes, enhancing the material’s suitability for clinical applications. In vitro cell-based assays confirmed the non-cytotoxic nature of the optimal adhesives, with metabolic activity showing significant increases over a 7-day period. These advancements support the development of improved tissue adhesives, potentially reducing reliance on sutures and enhancing wound healing outcomes. Full article

In this study, a novel semi-liquid gel material based on bisphenol A-type epoxy resin (E51), methylhexahydrophthalic anhydride (MHHPA), and epoxidized soybean oil (ESO) was developed for high-performance wellbore sealing. The gel system exhibits tunable gelation times ranging from 1 to 10 h (±0.5 h) and maintains a low viscosity of <100 ± 2 mPa·s at 25 °C, enabling efficient injection into the wellbore. The optimized formulation achieved a compressive strength exceeding 112.5 ± 3.1 MPa and a breakthrough pressure gradient of over 50 ± 2.8 MPa/m with only 0.9 PV dosage. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of a dense, crosslinked polyester network. Interfacial adhesion was significantly enhanced by the incorporation of 0.25 wt% octadecyltrichlorosilane (OTS), yielding an adhesion layer thickness of 391.6 ± 12.7 nm—approximately 9.89 times higher than that of the unmodified system. Complete degradation was achieved within 48 ± 2 h at 120 °C using a γ-valerolactone and p-toluenesulfonic acid solution. These results demonstrate the material’s potential as a high-strength, injectable, and degradable sealing solution for complex subsurface environments. Full article

Background/Objectives: This Phase 3, randomised, double-blind, multicentre trial evaluated the efficacy and safety of a novel hyaluronic acid hydrogel cross-linked with hexamethylenediamine (HMDA-HA) compared to a conventional 1,4-butanediol diglycidyl ether cross-linked HA (BDDE-HA) in patients with mild-to-moderate knee osteoarthritis (OA). Methods: A total of 223 adults (mean age 63.5 years; 167 women) with Kellgren–Lawrence (KL) grade I–III knee OA were randomised 1:1 to receive two intra-articular injections of HMDA-HA or BDDE-HA at baseline and at 24 weeks. The primary endpoint was changes from baseline in weight-bearing pain (WBP) on a 100 mm visual analogue scale (VAS) at Week 12, assessed in the per-protocol population. A non-inferiority margin of 10 mm was predefined. Secondary outcomes included global assessments, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index scores, responder rates, and rescue medication use [ClinicalTrials.gov: NCT06307847]. Results: At Week 12, least squares mean change (standard error [SE]) in WBP was −23.72 (1.88) mm in the HMDA-HA group (n = 83) and −25.99 (1.76) mm in the BDDE-HA group (n = 95), yielding a difference of 2.26 mm (95% confidence interval [CI]: −2.83 to 7.34; p = 0.3825), thus demonstrating the non-inferiority of HMDA-HA to BDDE-HA. Secondary outcomes were comparable between groups. A total of 136 adverse events were reported: 44 (41.1%) in the HMDA-HA group and 32 (28.1%) in the BDDE-HA group, with no treatment-related adverse drug reactions. Conclusions: A single-injection intra-articular regimen of HMDA-HA was effective and safe for the treatment of adult patients with mild-to-moderate knee OA. Full article

The inspection of oil storage tanks is a critical measure to prevent the risk of oil leakage. Therefore, research has focused on magnet-type climbing robots for automated tank inspections. While existing magnet-type climbing robots have demonstrated significant improvements in climbing steel structures, their capability in terms of metal thickness measurement has not been previously evaluated. During thickness inspections, ultrasonic thickness sensors require a probe to be pressed against target surfaces. To automate metal thickness measurements, this pressing motion of the probe needs to be performed by the robot. This study introduces a novel metal thickness measurement device comprising an ultrasonic probe, a linear actuator, a gel pump, and a pressure sensor designed for a magnet-type climbing robot. The linear actuator moves the probe to its initial position, the gel pump injects a coupling gel, and then the actuator moves the probe to the surface and back. Finally, our prototype of an ultrasonic probe with a linear actuator was installed on a magnet-type climbing robot to demonstrate its functionality in a practical application regarding an oil storage tank inspection system. The prototype achieved a measurement success rate of 65.9% and an average error of 0.7% compared to a reference thickness. This article details the design and development of the ultrasonic probe with a linear actuator to enable the probe to make contact with the surface. It then details the experimental results and evaluation of metal thickness measurement performed using the prototype and the climbing robot. Full article

Retinal diseases can result in blindness and visual impairment. They represent a significant medical burden and adversely affect life expectancy. Recently, antibody- and nucleic acid-based pharmaceuticals have increasingly been used to treat retinal diseases, with improvement or cure as the goal; however, these drugs are currently only administered by intravitreal injection. In this study, we present a novel approach to treating retinal diseases using eye drops that contain PnkRNA, a single-stranded RNA nucleic acid. PnkRNA-loaded liposomes were shown to effectively deliver retinal drugs and significantly inhibit retinal thickening in a mouse retinal-vein occlusion model. Cationic modification of the liposome surface enhanced the delivery of nucleic acids and therapeutic efficacy. Moreover, to reduce the frequency of eye-drop administration, liposomes were incorporated into the thermoresponsive gels. This formulation provided sustained retinal delivery and exhibited superior therapeutic efficacy compared with liposomal eye drops. This nucleic acid retinal delivery technology represents a significant advancement in drug-delivery technology, offering a safe and simple treatment for retinal diseases. Full article