Liquid Hydrogel Research Articles

Quasi-solid-state silicon-air batteries with high capacities and wide-temperature adaptabilities

Silicon-air batteries (SABs) have emerged as significant energy conversion devices due to its high theoretical energy density and favorable energy-to-cost ratios. However, their application is limited by low anode utilization, electrolyte leakage and aqueous configuration. According, herein, a PAAK-M-ionic liquid (IL) hydrogel (PAAK-M-IL) has been developed using a hygroscopic IL, 1-ethyl-3-methylimidazolium chloride (EMImCl), as an additive for the twin-chain PAAK-M. This PAAK-M-IL demonstrates a high conductivity of 332 mS cm-1 and a significant water uptake of 1486 % at room temperature. Quasi-solid-state silicon-air batteries (QSSSABs) constructed based on the PAAK-M-IL exhibit a remarkable specific capacity of 184.47 Ah kg-1, achieving a lifespan of nearly 121 h. Crucially, the QSSSABs exhibit excellent stability and practicality across a wide temperature range (-10 °C to 60 °C) and under harsh conditions, such as water immersion, rinsing, and liquid nitrogen soaking. A QSSSAB is capable of powering a digital clock/a music player in extreme weather and adverse environments. This research marks a groundbreaking achievement in the development of high-performance, practical, and adaptable QSSSABs, effectively addressing the challenges of SABs application in practical scenarios and providing a robust technical foundation for their future advancement.

A novel biological antibacterial polyvinyl alcohol/polyionic liquid hydrogel for wound dressing.

The release of antibiotics or anions by traditional bacteriostatic agents led to the development of bacterial drug resistance and environmental pollution. Ionic liquids (ILs) have become important choices for antibacterial agents because of their excellent physical, chemical and biological properties. In this paper, the bioactivities of 1-vinyl-3-butylimidazolium chloride ([VBIM]Cl, IL) and poly (1-vinyl-3-butylimidazolium chloride) (P[VBIM]Cl, PIL) were evaluated, and the potential antibacterial material was used to synthesize hydrogels. Using the colony formation assay and the Oxford cup method, antibacterial effect of IL and PIL were tested. Cell-Counting-Kit-8 (CCK-8) experiments were used to study the IC50 (half maximal inhibitory concentration) values of IL and showed 1.47mg/mL, 0.35mg/mL and 0.33mg/mL at 24 h, 48 h and 72 h, respectively. The IC50 value of PIL were 12.15μg/mL, 12.06μg/mL and 11.76μg/mL at 24 h, 48 h and 72 h, respectively. The PIL is further crosslinked with polyvinyl alcohol (PVA) to form a novel hydrogel through freeze-thaw cycles. The newly fabricated hydrogel exhibited a high water content, excellent water absorption properties and outstanding mechanical performance. Using the colony formation assay and the inhibition zone assay, the hydrogels exhibited favorable antibacterial effects (against E.coli and S.aureus) such that nearly 100% of the bacteria were killed in liquid medium while cultivating with H4 (synthesized by 0.5g PIL and 1g PVA). In addition, the cytotoxicity of PIL was significantly reduced through hydrogen bond crosslinking. H4 showed the highest antibacterial activity and a good biocompatibility. The results indicated that the PVA&PIL hydrogels had great potential for wound dressing.

Rodent Model of Masseter Volumetric Muscle Loss for Studying Bioengineering Materials.

Craniofacial volumetric muscle loss (VML) injuries can occur as a result of severe trauma, surgical excision, inflammation, and congenital or other acquired conditions. Treatment of craniofacial VML involves surgical, functional muscle transfer. However, these procedures are unable to restore normal function, sensation, or expression, and more commonly, these conditions go untreated. Very little research has been conducted on skeletal muscle regeneration in animal models of craniofacial VML. This manuscript describes a rat model for the study of craniofacial VML injury and a protocol for the histological evaluation of biomaterials in the treatment of these injuries. Liquid hydrogel and freeze-dried scaffolds are applied at the time of surgical VML creation, and masseters are excised at terminal time points up to 12 weeks with high retention rates and negligible complications. Hematoxylin and eosin (HE), Masson's Trichrome, and immunohistochemical analysis are used to evaluate parameters of skeletal muscle regeneration as well as biocompatibility and immunomodulation. While we demonstrate the study of a hyaluronic-acid-based hydrogel, this model provides a means for evaluating subsequent iterations of materials in VML injuries.

Hydrogels and Carbon Nanotubes: Composite Electrode Materials for Long-Term Electrocardiography Monitoring.

This paper presents methods for developing high-performance interface electrode materials designed to enhance signal collection efficacy during long-term (over 24 h) electrocardiography (ECG) monitoring. The electrode materials are fabricated by integrating commercial ECG liquid hydrogels with carbon nanotubes (CNTs), which are widely utilized in dry-electrode technologies and extensively discussed in the current scientific literature. The composite materials are either prepared by dispersing CNTs within the commercial liquid hydrogel matrix or by encasing the hydrogels in macroscopic CNT films. Both approaches ensure the optimal wetting of the epidermis via the hydrogels, while the CNTs reduce material impedance and stabilize the drying process. The resulting electrode materials maintain their softness, allowing for micro-conformal skin attachment, and are biocompatible. Empirical testing confirms that the ECG electrodes employing these hybrid hydrogels adhere to relevant standards for durations exceeding 24 h. These innovative hybrid solutions merge the benefits of both wet and dry ECG electrode technologies, potentially facilitating the extended monitoring of ECG signals and thus advancing the diagnosis and treatment of various cardiac conditions.

Curcumin-Based Ionic Liquid Hydrogel for Topical Transdermal Delivery of Curcumin To Improve Its Therapeutic Effect on the Psoriasis Mouse Model.

Psoriasis is a systemic, recurrent, chronic autoimmune skin disease. However, psoriasis drugs have poor skin permeability and high toxicity, resulting in low bioavailability and affecting their clinical application. In this study, we propose a curcumin-based ionic liquid hydrogel loaded with ilomastat (Cur-Car-IL@Ilo hydrogel), which can effectively maintain the sustained release of drugs and improve the skin permeability of drugs. We used a model of imiquimod-induced psoriasis and demonstrated that local application of Cur-Car-IL@Ilo hydrogel can improve skin lesions in mice with significantly reduced expression levels of inflammatory factors, matrix metalloproteinase 8, and collagen-I. The expressions of iron death-related proteins SLC7A11 and ASL4 were significantly decreased after treatment with Cur-Car-IL@Ilo hydrogel. Flora analysis showed that the content of anaerotruncus, proteus, and UCG-009 bacteria in the gut of psoriatic mice increased. The levels of paludicola, parabacteroides, prevotellaceae_UCG-001, escherichia-shigella, and aerococcus decreased, and the levels of some of the above bacteria tended to be normal after treatment. Therefore, the curcumin-based ionic liquid hydrogel can be used as a multifunctional, nonirritating, noninvasive, and highly effective percutaneous treatment of psoriasis.

Versatile Mechanically Tunable Hydrogels for Therapeutic Delivery Applications.

Hydrogels provide a versatile platform for biomedical material fabrication that can be structurally and mechanically fine-tuned to various tissues and applications. Applications of hydrogels in biomedicine range from highly dynamic injectable hydrogels that can flow through syringe needles and maintain or recover their structure after extrusion to solid-like wound-healing patches that need to be stretchable while providing a selective physical barrier. In this study, a toolbox is designed using thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) polymeric matrices and nanocelluloses as reinforcing agent to obtain biocompatible hydrogels with altering mechanical properties, from a liquid injectable to a solid-like elastic hydrogel. The liquid hydrogels possess low viscosity and shear-thinning properties at 25 °C, which allows facile injection at room temperature, while they become viscoelastic gels at body temperature. In contrast, the covalently cross-linked solid-like hydrogels exhibit enhanced viscoelasticity. The liquid hydrogels are biocompatible and are able to delay the in vitro release and maintain the bioactivity of model drugs. The antimicrobial agent loaded solid-like hydrogels are effective against typical wound-associated pathogens. This work presents a simple method of tuning hydrogel mechanical strength to easily adapt to applications in different soft tissues and broaden the potential of renewable bio-nanoparticles in hybrid biomaterials with controlled drug releasecapabilities.

Effect of Amino Acid Types on the Mechanical and Antimicrobial Properties of Amino Acid-Based Polyionic Liquid Hydrogels.

Polyionic liquid hydrogels attract increasing attention due to their unique properties and potential applications. However, research on amino acid-based polyionic liquid hydrogels is still in its infancy stage. Moreover, the effect of amino acid types on the properties of hydrogels is rarely studied to date. In this work, amino acid-based polyionic liquid hydrogels (D/L-PCAA hydrogels) are synthesized by copolymerizing vinyl choline-amino acid ionic liquids and acrylic acids using Al3+ as a crosslinking agent and bacterial cellulose (BC) as a reinforcing agent. The effects of amino acid types on mechanical and antimicrobial properties are systematically investigated. D-arginine-based hydrogel (D-PCArg) shows the highest tensile strength (220.7 KPa), D-phenylalanine-based hydrogel (D-PCPhe) exhibits the highest elongation at break (1346%), and L-aspartic acid-based hydrogel (L-PCAsp) has the highest elastic modulus (206.9 KPa) and toughness (1.74MJ m-3). D/L-PCAsp hydrogels demonstrate stronger antibacterial capacity against Escherichia coli and Staphylococcus aureus, and D/L-PCPhe hydrogels possess higher antifungal activity against Cryptococcus neoformans. Moreover, the resultant hydrogels exhibit prominent hemocompatibility and low toxicity, as well as excellent self-healing capabilities (86%) and conductivity (2.8 S m-1). These results indicate that D/L-PCAA hydrogel provides a promise for applications in wound dressings.

Acoustic Cell Patterning for Structured Cell-Laden Hydrogel Fibers/Tubules.

Cell-laden hydrogel fibers/tubules are one of the fundamentals of tissue engineering. They have been proven as a promising method for constructing biomimetic tissues, such as muscle fibers, nerve conduits, tendon and vessels, etc. However, current hydrogel fiber/tubule production methods have limitations in ordered cell arrangements, thus impeding the biomimetic configurations. Acoustic cell patterning is a cell manipulation method that has good biocompatibility, wide tunability, and is contact-free. However, there are few studies on acoustic cell patterning for fiber production, especially on the radial figure cell arrangements, which mimic many native tissue-like cell arrangements. Here, an acoustic cell patterning system that can be used to produce hydrogel fibers/tubules with tunable cell patterns is shown. Cells can be pre-patterned in the liquid hydrogel before being extruded as cross-linked hydrogel fibers/tubules. The radial patterns can be tuned with different complexities based on the acoustic resonances. Cell viability assays after 72h confirm good cell viability and proliferation. Considering the biocompatibility and reliability, the present method can be further used for a variety of biomimetic fabrications.

Enhanced Stability and Catalytic Activity of a Nanocatalyst with Reusable Ionic Liquid Hydrogels for the Reduction of Organic Pollutants.

Nitroaromatic compounds have a wide range of applications. However, they pose a significant threat to both the environment and human health. Ionic liquid hydrogels (ILs-gels) have emerged as a cost-effective and environmentally friendly option for various applications. However, conventional ILs-gels are known to possess mechanical flaws or defects. The procedure utilized a facile synthesis route that involved the polymerization of acrylamide (AM) and ionic liquids (ILs) to create a novel candidate for nanoparticle absorption. This study resolved this issue by creating toughened hydrophobic combined hydrogels synthesized through the addition of SiO2@poly(butyl acrylate) core-shell inorganic-organic hybrid latex particles (SiO2@PBA) to the AM-ILs mixture. The SiO2@PBA particles were chosen to provide the hydrogels with exceptional stretchability (up to 4050% strain) and high mechanical properties (tensile strength of 126 kPa) by acting as both a nanotoughener and a cross-linking point for hydrophobic linkage. Additionally, the P(AM/ILs)-SiO2@PBA hydrogel served as a template for the in situ and stable formation of palladium (Pd) nanoparticles. By incorporation of these Pd nanoparticles as catalysts into P(AM/ILs)-SiO2@PBA hydrogel carriers, the resulting P(AM/ILs)-SiO2@PBA/Pd hydrogels exhibited the ability to catalyze the degradation of p-nitrophenol. Remarkably, even after 15 applications, the efficiency of the degradation process remained consistently above 90%. Thus, the innovative SiO2@PBA toughened ILs-hydrogel design strategy can be utilized to develop robust and stretchable hydrogel materials for catalytic use in the sewage disposal industry.

Synthetic solutions for re‐growing human corneas

Cornea blindness is still treated mainly by corneal transplantation, using donated allograft human corneas. However, a severe global shortfall leaves an estimated 12.7 million patients on waiting lists despite methods of using one cornea for two different partial‐thickness grafts. Even more individuals are not on waiting lists because they have no access to transplantation in their countries or regions. However, even if donor tissues were readily available, patients with inflamed, severely damaged corneas are at high risk of rejecting conventional transplantation. Various solutions have been proposed as alternatives to corneal allografting, including the development of keratoprostheses and stem cell grafting. We posited using cell‐free implants that mimic the extracellular matrix of the human cornea to recapitulate the environment during corneal development and stimulate the endogenous cells within the patient's eyes to affect regeneration. We used cell‐free corneal implants made from chemically crosslinked recombinant human collagen to promote in situ tissue regeneration in pathologic corneas, including high‐risk ones. We successfully developed and tested recombinant human solid collagen‐based implants that promoted stable regeneration in inflamed human patient corneas based on phosphorylcholine (MPC). However, solid corneas require a full operating theatre and staffing, which is costly and not accessible to more remote regions in Canada and globally. Burns and severe infections that can lead to perforations are medical emergencies that require immediate methods to seal the eye. In many centres, cyanoacrylate glue is used as a sealant, but this is toxic and kills surrounding cells, often necessitating follow‐on transplantation. We developed a synthetic, biocompatible, and adhesive liquid hydrogel (LiQD Cornea), which would replace these toxic cyanoacrylate glues. LiQD cornea is applied as a liquid but quickly adheres and gels within corneal tissue defects like a dental filling. It can be used to fill ulcers and other damaged areas. Then its similarity at a molecular level to a natural tissue framework promotes tissue regeneration, treating corneal perforations effectively without transplantation. Further, due to the synthetic nature of the material, risks associated with disease transmission are reduced compared to natural products. We see LiQD Cornea potentially used in outpatient clinics instead of operating theatres, maximizing practicality and minimizing health care costs.

Cellulosic protic ionic liquid hydrogel confined Pd nanoparticles for selective hydrogenation of α-angelica lactone and alkenes

A cellulosic protic ILs hydrogel with confining ability to Pd NPs was synthesized through a cyclic anhydride cross-linking reaction in TMG/DMSO/CO2 solvent system, presenting good catalytic activity for the hydrogenation of α-AL and common alkenes.

Facile Preparation of a Photo-Cross-Linked Silk Fibroin-Poly Ionic Liquid Hydrogel with Antifreezing and Ion Conductive Properties.

The silk fibroin (SF)/ionic liquid (IL) based hydrogel is a kind of remarkable substrate for flexible devices because of its subzero-temperature elasticity, electrical conductivity, and water retention, although the procedure of the gelation is considered complex and time-consuming. In this work, we introduced an approximate method for the development of novel photo-cross-linked SF/IL hydrogel, that is, SF-IMA/PIL hydrogel via the modification of silk fibroin chain with 2-isocyanatoethyl methacrylate (SF-IMA) in a certain ionic liquid with an unsaturated double bond. The chemical cross-linking between methacrylated SF and IL was triggered by UV light, while the physical cross-linking of the hydrogel was attributed to the β-sheet formation of SF in SF-IMA/IL mixed solution. In addition to being a UV-induced three-dimensional (3D) printable one, the SF-IMA/PIL hydrogel performed significant ionic conductivity between room temperature and -50 °C and water retention within a wide range of relative humidity, which were the featured advantages as the ionic liquid involved. Moreover, the static and dynamic mechanical tests demonstrated that the hydrogel reserved its great elasticity at -50 °C and displayed its stiffness transition temperatures between -100 and -70 °C.

Tunable Hydrogel Electronics for Diagnosis of Peripheral Neuropathy.

Peripheral neuropathy characterized by rapidly increasing numbers of patients is commonly diagnosed via analyzing electromyography signals obtained from stimulation-recording devices. However, existing commercial electrodes have difficulty in implementing conformal contact with skin and gentle detachment, dramatically impairing stimulation/recording performances. Here, we develop on-skin patches with polyaspartic acid-modified dopamine/ethyl-based ionic liquid hydrogel (PDEH) as stimulation/recording devices to capture electromyography signals for the diagnosis of peripheral neuropathy. Triggered by a one-step electric field treatment, the hydrogel achieves rapid and wide-range regulation of adhesion and substantially strengthened mechanical performances. Moreover, hydrogel patches assembled with a silver-liquid metal (SLM) layer exhibit superior charge injection and low contact impedance, capable of capturing high-fidelity electromyography. We further verify the feasibility of hydrogel devices for accurate diagnoses of peripheral neuropathy in sensory, motor, and mixed nerves. For various body parts, such as fingers, the elderly's loose skin, hairy skin, and children's fragile skin, we regulate the adhesion of PDEH-SLM devices to establish intimate device/skin interfaces or ensure benign removal. Noticeably, hydrogel patches achieve precise diagnoses of nerve injuries in these clinical cases while providing extra advantages of more effective stimulation/recording performances. These patches offer a promising alternative for the diagnosis and rehabilitation of neuropathy in future. This article is protected by copyright. All rights reserved.

Injectable bioorthogonal hydrogel (BIOGEL) accelerates tissue regeneration in degenerated intervertebral discs.

Intervertebral disc (IVD) degeneration is a leading cause of back pain and precursor to more severe conditions, including disc herniation and spinal stenosis. While traditional growth factor therapies (e.g., TGFβ) are effective at transiently reversing degenerated disc by stimulation of matrix synthesis, it is increasingly accepted that bioscaffolds are required for sustained, complete IVD regeneration. Current scaffolds (e.g., metal/polymer composites, non-mammalian biopolymers) can be improved in one or more IVD regeneration demands: biodegradability, noninvasive injection, recapitulated healthy IVD biomechanics, predictable crosslinking, and matrix repair induction. To meet these demands, tetrazine-norbornene bioorthogonal ligation was combined with gelatin to create an injectable bioorthogonal hydrogel (BIOGEL). The liquid hydrogel precursors remain free-flowing across a wide range of temperatures and crosslink into a robust hydrogel after 5-10min, allowing a human operator to easily inject the therapeutic constructs into degenerated IVD. Moreover, BIOGEL encapsulation of TGFβ potentiated histological repair (e.g., tissue architecture and matrix synthesis) and functional recovery (e.g., high water retention by promoting the matrix synthesis and reduced pain) in an in vivo rat IVD degeneration/nucleotomy model. This BIOGEL procedure readily integrates into existing nucleotomy procedures, indicating that clinical adoption should proceed with minimal difficulty. Since bioorthogonal crosslinking is essentially non-reactive towards biomolecules, our developed material platform can be extended to other payloads and degenerative injuries.

Flexible Zinc-Air Batteries with Ampere-Hour Capacities and Wide-Temperature Adaptabilities.

Flexible Zn-air batteries (FZABs) have significant potentials as efficient energy storage devices for wearable electronics because of their safeties and high energy-to-cost ratios. However, their application is limited by their short cycle lives, low discharge capacities per cycle, and high charge/discharge polarizations. Accordingly, herein, a poly(sodium acrylate)-polyvinyl alcohol (PANa-PVA)-ionic liquid (IL) hydrogel (PANa-PVA-IL) is prepared using a hygroscopic IL, 1-ethyl-3-methylimidazolium chloride, as an additive for twin-chain PANa-PVA. PANa-PVA-IL exhibits a high conductivity of 306.9mScm-1 and a water uptake of 2515 wt% at room temperature. Moreover, a low-cost bifunctional catalyst, namely, Co9 S8 nanoparticles anchored on N- and S-co-doped activated carbon black pearls 2000 (Co9 S8 -NSABP), is synthesized, which demonstrates a low O2 reversibility potential gap of 0.629V. FZABs based on PANa-PVA-IL and Co9 S8 -NSABP demonstrate high discharge capacities of 1.67mAhcm-2 per cycle and long cycle lives of 330h.Large-scale flexible rechargeable Zn-air pouch cells exhibit total capacities of 1.03Ah and energy densities of 246Whkgcell -1 . This study provides new information about hydrogels with high ionic conductivities and water uptakes and should facilitate the application of FZABs in wearable electronics.

Topical Wound Treatment with a Nitric Oxide-Releasing PDE5 Inhibitor Formulation Enhances Blood Perfusion and Promotes Healing in Mice.

Chronic, non-healing wounds constitute a major health problem, and the current therapeutic options are limited. Therefore, pharmaceuticals that can be locally applied to complicated wounds are urgently needed. Such treatments should directly target the underlying causes, which include diabetes mellitus, chronic local pressure and/or vascular insufficiency. A common consequence of these disorders is impaired wound angiogenesis. Here, we investigated the effect of topical application of a nitric oxide-releasing phosphodiesterase 5 inhibitor (TOP-N53)-containing liquid hydrogel on wound repair in mice. The drug-loaded hydrogel promoted re-epithelialization and angiogenesis in wounds of healthy and healing-impaired diabetic mice. Using a non-invasive label-free optoacoustic microscopy approach combined with automated vessel analysis, we show that the topical application of TOP-N53 formulation increases the microvascular network density and promotes the functionality of the newly formed blood vessels, resulting in enhanced blood perfusion of the wounds. These results demonstrate a remarkable healing-stimulating activity of topically applied TOP-N53 formulation, supporting its further development as a wound therapeutic.

Zwitterionic liquid hydrogel sustained-release strategy for high-performance nanofiltration membrane

Controlling the diffusion of amine monomers plays a crucial role in fabricating well-defined architecture and high-performance nanofiltration (NF) membranes through interfacial polymerization (IP). Herein, a sustained-release strategy was proposed to regulate the interfacial polymerization through a zwitterionic liquid hydrogel transition layer. The hydrogel (Gel) was fabricated via in-situ one-step UV photo-initiated free-radical polymerization between 1-vinyl-3-ethylimidazolium chloride ([VEIm][Cl]) and 3-sulfopropyl methacrylate potassium salt (SMP) on the polyethersulfone (PES) substrate. The polyamide (PA) layer was then formed on the Gel layer by mitigating the diffusion of amine monomers. Low-field time-domain nuclear magnetic resonance (TD NMR) analysis demonstrated that the Gel layer significantly enhanced the water-absorbing capacity of the composite membrane. Positron annihilation lifetime spectroscopy (PALS) also confirmed the Gel-PA composite membrane possessed enlarged free volumes. The obtained Gel-PA composite membrane displayed a permeance of 13.22 L m−2 h−1 bar−1, a high Na2SO4 rejection of 98.23 %, a favorable NaCl/Na2SO4 selectivity of 49.75, outstanding long-term operational stability, and membrane antifouling properties. This sustained-release strategy provides a facile and feasible approach to controlling the IP process and obtaining high-performance nanofiltration membranes.

Highly compressible hydrogel reinforced with cellulose nanocrystals for ultrasound scanning via microwave-assisted synthesis

In this study, a rapid fabrication method was developed to prepare hydrogel structures with high mechanical strength and low attenuation coefficient for ultrasound scanning. Poly acrylic acid (PAA) hydrogel was first prepared via a free radical polymerization approach. To shorten the process time (~ 30 min in water bath), microwave heating was applied to facilitate the reaction and reduce the reaction time down to 80 s. The produced hydrogels showed excellent elasticity but had a low compressive strength of 100 kPa. To further enhance the mechanical strengths of PAA hydrogels, cellulosenanocrystals (CNCs) were added to the precursor solution. After the microwave assisted crosslinking process, the compressive strength of the hydrogel increased to 350 kPa. Moreover, the ultimate compressive strain was enhanced from 60 to 80% with great recoverability. The PAA/CNC hydrogel has a great ultrasound trnansimission for high-quality ultrasound images comparable to conventional liquid hydrogels. To demonstrate the feasibility of the PAA/CNC hydrogel in ultrasonic medical applications, a customized ultrasound probe coat was created with a 3D printed mold and practically used in the ultrasound scanning process.

A novel intrauterine barrier for preventing the recurrence of IUA after TCRA procedure

Intrauterine adhesion (IUA) is the result of abnormal endometrium repair after trauma and infection that damages the basal layer of the endometrium, which is then replaced by scar tissue. In such instances, the endometrium partially or completely loses the ability to conceive the embryo. Even after surgery-based comprehensive treatment, a high rate of adhesion remains. A thin endometrium, poor blood supply, and poor function may also lead to refractory infertility, resulting in a poor reproductive prognosis even when the uterine cavity has been completely restored to normal. Therefore, two key points of postoperative management are the use of an intrauterine barrier to prevent re-adhesion and medicine to promote endometrial repair. However, there is currently no clinically applicable barrier that can meet the personalized dimensions of uterine cavity shape and size or effectively separate the wound wall. We have designed an intrauterine barrier that consists of a unique uterine-shaped, estrogen-release intrauterine device (IUD), which can be combined with an injectable, temperature-sensitive hydrogel. For this study, we will insert an estrogen-release IUD into the uterine cavity following transcervical resection of adhesion (TCRA) surgery, at the same time injecting 3–5 mL of liquid hydrogel at room temperature into the uterine cavity via the cervical channel. Due to its temperature sensitivity, the hydrogel will gradually solidify into a jellylike consistency, filling the uterine cavity with a solid barrier and completely preventing contact with the wounded wall to avoid the recurrence of adhesion. The estrogen-release IUD will be wrapped in the hydrogel barrier, which has many pores that allow sustainable estrogen release to promote endometrial regeneration and repair. This protocol can meet the needs of postoperative management of TCRA, but experimental and clinical studies are still needed to demonstrate its effectiveness. If patients in the study group have a lower adhesion recurrence and higher pregnancy rate compared to controls, our hypothesis will be confirmed that this barrier will prove a clinical application to help the functional repair of the endometrium and achieve a good reproductive prognosis.

Focal injection of a radiopaque viscous spacer before focal brachytherapy as re-irradiation for locally recurrent prostate cancer

PURPOSEClose vicinity of the target volume and a sensitive organ may prevent an effective radiotherapy/brachytherapy. A liquid hydrogel spacer cannot be placed well focally in specific small areas or fatty tissue. The purpose of this study was to report the injection technique and results of a radiopaque viscous hydrogel spacer. METHODSThe radiopaque viscous spacer was applied focally using transrectal ultrasound guidance before focal brachytherapy in re-irradiated areas in two patients. The technical feasibility of the injection between the recurrence and the rectum / bladder, the resulting distance, visibility in different imaging modalities, stability within several months, dose distribution, toxicity and tumor control up to 18 months after treatment was analyzed. RESULTSAfter hydrodissection, the needle was moved from the base towards the apex during injection of each syringe, respectively. The viscous spacer could be successfully injected focally and resulted in a planned distancing of the target volume (right lobe and seminal vesicle area) and the rectum of at least 1 cm and additional distancing to the bladder of at least 5 mm. Both brachytherapy treatments were performed without relevant toxicities. The PSA nadirs indicated a satisfactory short-term response to the treatment. CONCLUSIONSThe viscous hydrogel spacer can be injected focally at a specific prostate lobe or seminal vesicles. A viscous spacer remains stable within fatty tissue in any areas that are accessible by an ultrasound guided needle injection to create a distance between the high brachytherapy dose within the target and the organ at risk.