Montmorillonite-based polyacrylamide hydrogel rings for controlled vaginal drug delivery

Highly effective removal of basic fuchsin dye using carboxymethyl konjac glucomannan grafted acrylic acid-acrylamide/montmorillonite composite hydrogel

This study developed a nanocomposite hydrogel, CAM4-MMT, for efficiently removing basic fuchsin dye from water. The hydrogel was prepared by grafting a copolymer of acrylic acid (AA) and acrylamide (AM) onto carboxymethyl konjac glucomannan (CMKGM), and doped with montmorillonite (MMT), exhibited excellent thermal stability, a porous inner structure, large specific surface area (1.407 m2/g), and high swelling capacity (107.3 g/g). The hydrogel achieved a maximum adsorption capacity of 694.1 mg/g and a removal rate of 99.5 %. The Langmuir isotherm and pseudo-second-order kinetic model best described the adsorption process. Regeneration and reuse tests confirmed that the hydrogel has excellent recyclability. In conclusion, the CAM4-MMT composite hydrogel efficiently removed basic fuchsin from water solutions, offering a new scheme for eliminating basic fuchsin using natural polysaccharides with promising applications.

Nanoclay-Composite Hydrogels for Bone Tissue Engineering

Nanoclay-composite hydrogels represent a promising avenue for advancing bone tissue engineering. Traditional hydrogels face challenges in providing mechanical strength, biocompatibility, and bioactivity necessary for successful bone regeneration. The incorporation of nanoclay into hydrogel matrices offers a potential unique solution to these challenges. This review provides a comprehensive overview of the fabrication, physico-chemical/biological performance, and applications of nanoclay-composite hydrogels in bone tissue engineering. Various fabrication techniques, including in situ polymerization, physical blending, and 3D printing, are discussed. In vitro and in vivo studies evaluating biocompatibility and bioactivity have demonstrated the potential of these hydrogels for promoting cell adhesion, proliferation, and differentiation. Their applications in bone defect repair, osteochondral tissue engineering and drug delivery are also explored. Despite their potential in bone tissue engineering, nanoclay-composite hydrogels face challenges such as optimal dispersion, scalability, biocompatibility, long-term stability, regulatory approval, and integration with emerging technologies to achieve clinical application. Future research directions need to focus on refining fabrication techniques, enhancing understanding of biological interactions, and advancing towards clinical translation and commercialization. Overall, nanoclay-composite hydrogels offer exciting opportunities for improving bone regeneration strategies.

Injectable and Photocurable Gene Scaffold Facilitates Efficient Repair of Spinal Cord Injury

RNA interference-based gene therapy has led to a strategy for spinal cord injury (SCI) therapy. However, there have been high requirements regarding the optimal gene delivery vector for siRNA-based SCI gene therapy. Here, we developed an injectable and photocurable lipid nanoparticle GelMA (PLNG) hydrogel scaffold for controlled dual siRNA delivery at the SCI wound site. The prepared PLNG scaffold could efficiently protect and retain the bioactivity of the siRNA nanocomplex. It facilitated sustainable siRNA release along with degradation in 7 days. After loading dual siRNA targeting phosphatase and tensin homologue (PTEN) and macrophage migration inhibitory factor (MIF) simultaneously, the locally administered siRNAs/PLNG scaffold efficiently improved the Basso mouse scale (BMS) score and recovered ankle joint movement and plantar stepping after treatment with only three doses. We further proved that the siRNAs/PLNG scaffold successfully regulated the activities of neurons, microglia, and macrophages, thus promoting neuron axon regeneration and remyelination. The protein array results suggested that the siRNAs/PLNG scaffold could increase the expression of growth factors and decrease the expression of inflammatory factors to regulate neuroinflammation in SCI and create a neural repair environment. Our results suggested that the PLNG scaffold siRNA delivery system is a potential candidate for siRNA-based SCI therapy.

Chondroitin Sulphate: An emerging therapeutic multidimensional proteoglycan in colon cancer

Chondroitin sulfate (CS) is a sulfated glycosaminoglycan (GAG) that has captured massive attention in the field of drug delivery. As the colon is considered the preferred site for local and systemic delivery of bioactive agents for the treatment of various diseases, colon-targeted drug delivery rose to the surface of research. Amid several tactics to attain colon-targeted drug release, the exploitation of polymers degraded by colonic bacteria holds great promise. Chondroitin sulfate as a biodegradable, biocompatible mucopolysaccharide is known for its anti-inflammatory, anti-osteoarthritis, anti-atherosclerotic, anti-oxidant, and anti-coagulant effects. Besides these therapeutic functions, CS thrived to play a major role in nanocarriers as a matrix material, coat, and targeting ligand. This review focuses on the role of CS in nanocarriers as a matrix material or as a targeting moiety for colon cancer therapy, relating the present applications to future perspectives.

Montmorillonite-Sodium Alginate Oral Colon-Targeting Microcapsule Design for WGX-50 Encapsulation and Controlled Release in Gastro-Intestinal Tract

The montmorillonite-sodium alginate (MMT-SA) colon-targeting microcapsules have been designed as a WGX-50 encapsulation and controlled release vehicle used in oral administration. The MMT-SA microcapsule was formed from a cross-linking reaction, and the stable micropore in the microcapsule changed with a different MMT-SA mixed mass ratio. The MMT-SA microcapsule has a reinforced micropore structure and an enhanced swell-dissolution in SIF and SCF with alkaline environment, which is attributed to the incorporated MMT. The MMT-SA microcapsule exhibited a high WGX-50 encapsulation rate up to 98.81 ± 0.31% and an obvious WGX-50 controlled release in the simulated digestive fluid in vitro. The WGX-50 loaded with MMT-SA microcapsule showed a weak minimizing drug loss in SGF (Simulated Gastric Fluid) with an acidic environment, while it showed a strong maximizing drug release in SIF (Simulated Intestinal Fluid) and SCF (Simulated Colonic Fluid) with an alkaline environment. These features make the MMT-SA microcapsule a nominated vehicle for colon disease treatment used in oral administration.

pH-responsive magnetic biocompatible chitosan-based nanocomposite carrier for ciprofloxacin release

The pH-sensitive and magnetic-triggered release ensures the effective delivery of drugs. Chitosan carries amine pendants that encourage the fabrication of pH-responsive carriers. Montmorillonite (MMt), an attractive nano-clay in drug delivery possessing high encapsulation properties, was magnetized through the co-precipitation of Fe3+/Fe2+ ions. The study aimed to integrate the magnetic montmorillonite (mMMt) into the chitosan matrix and crosslinked by citric acid (CA) to achieve the nanocomposite carrier with double-responsive features for effective drug delivery. The release evaluation revealed that coating the mMMt with CA-crosslinked chitosan prevented the burst release of Ciprofluxcacin (Cip). The nanocomposite showed a high sustained release, and the release rate in the neutral environment (pH 7.4) was remarkably higher than in acidic media (pH 5.8). The new nanocomposite carrier showed high encapsulation efficiency to Cip (about 98 %). The study was developed by investigating external magnetic effects on the release rate, which lead to an increase in the release rate. The kinetics studies confirmed the diffusion mechanism for Cip release in all experimental media. The Cip-loaded nanocomposite carriers showed antibacterial activity against E. coli and S. aureus.

Vaginal Drug Delivery Systems to Control Microbe-Associated Infections

The vagina has been regarded as a crucial route for drug delivery. Despite the wide range of available vaginal dosage forms for vaginal infection control, poor drug absorptivity remains a significant challenge due to various biological barriers in the vagina, such as mucus, epithelium, immune systems, and others. To overcome these barriers, different types of vaginal drug delivery systems (VDDSs), with outstanding mucoadhesive, mucus-penetrating properties, have been designed to enhance the absorptivity of vagina-administered agents in the past decades. In this Review, we introduce a general understanding of vaginal administration, its biological barriers, the commonly used VDDSs, such as nanoparticles and hydrogels, and their applications in controlling microbe-associated vaginal infections. Additionally, further challenges and concerns regarding the design of VDDSs will be discussed.

Three-Dimensionally Printed Vaginal Rings: Perceptions of Women and Gynecologists in a Cross-Sectional Survey

Three-dimensional printing technologies can be implemented for the fabrication of personalized vaginal rings (VRs) as an alternative approach to traditional manufacturing. Although several studies have demonstrated the potential of additive manufacturing, there is a lack of knowledge concerning the opinions of patients and clinicians. This study aimed to investigate the perception of women and gynecologists regarding VRs with personalized shapes. The devices were printed with different designs (traditional, "Y", "M", and flat circle) by Fused Deposition Modeling for a cross-sectional survey with 155 participants. Their anticipated opinion was assessed through a questionnaire after a visual/tactile analysis of the VRs. The findings revealed that most women would feel comfortable using some of the 3D-printed VR designs and demonstrated good acceptability for the traditional and two innovative designs. However, women presented multiple preferences when the actual geometry was assessed, which directly related to their age, previous use of the vaginal route, and perception of comfort. In turn, gynecologists favored prescribing traditional and flat circle designs. Overall, although there was a difference in the perception between women and gynecologists, they had a positive opinion of the 3D-printed VRs. Finally, the personalized VRs could lead to an increase in therapeutic adherence, by meeting women's preferences.

A novel nanocomposite containing zinc ferrite nanoparticles embedded in carboxymethylcellulose hydrogel plus carbon nitride nanosheets with multifunctional bioactivity

A novel and biologically active nanobiocomposite is synthesized based on carbon nitride nanosheet (g-C3N4) based carboxymethylcellulose hydrogels with embedded zinc ferrite nanoparticles. Physical-chemical aspects, morphological properties, and their multifunctional biological properties have been considered in the process of evaluation of the synthesized structure. The hydrogels' compressive strength and compressive modulus are 1.98 ± 0.03 MPa and 3.46 ± 0.05 MPa, respectively. Regarding the biological response, it is shown that the nanobiocomposite is non-toxic and biocompatible, and hemocompatible (with Hu02 cells). In addition, the developed material offers a suitable antibacterial activity for both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

Feather keratin-montmorillonite nanocomposite hydrogel promotes bone regeneration by stimulating the osteogenic differentiation of endogenous stem cells

Bone defects caused by bone trauma, infection, surgery, or other systemic diseases remain a severe challenge for the medical field. To address this clinical problem, different hydrogels were exploited to promote bone tissue regrowth and regeneration. Keratins are natural fibrous proteins found in wool, hair, horns, nails, and feather. Due to their unique characteristics of outstanding biocompatibility, great biodegradability, and hydrophilic, keratins have been widely applicated in different fields. In our study, the feather keratin-montmorillonite nanocomposite hydrogels that consist of keratin hydrogels serving as the scaffold support to accommodate endogenous stem cells and montmorillonite is synthesized. The introduction of montmorillonite greatly improves the osteogenic effect of the keratin hydrogels via bone morphogenetic protein 2 (BMP-2)/phosphorylated small mothers against decapentaplegic homolog 1/5/8 (p-SMAD 1/5/8)/runt-related transcription factor 2 (RUNX2) expression. Moreover, the incorporation of montmorillonite into hydrogels can improve the mechanical properties and bioactivity of the hydrogels. The morphology of feather keratin-montmorillonite nanocomposite hydrogels was shown by scanning electron microscopy (SEM) to have an interconnected porous structure. The incorporation of montmorillonite into the keratin hydrogels was confirmed by the energy dispersive spectrum (EDS). We prove that the feather keratin-montmorillonite nanocomposite hydrogels enhance the osteogenic differentiation of BMSCs. Furthermore, micro-CT and histological analysis of rat cranial bone defect demonstrated that feather keratin-montmorillonite nanocomposite hydrogels dramatically stimulated bone regeneration in vivo. Collectively, feather keratin-montmorillonite nanocomposite hydrogels can regulate BMP/SMAD signaling pathway to stimulate osteogenic differentiation of endogenous stem cells and promote bone defect healing, indicating their promising candidate in bone tissue engineering.

Release Kinetics of Metronidazole from 3D Printed Silicone Scaffolds for Sustained Application to the Female Reproductive Tract

Sustained vaginal administration of antibiotics or probiotics has been proposed to improve treatment efficacy for bacterial vaginosis. 3D printing has shown promise for development of systems for local agent delivery. In contrast to oral ingestion, agent release kinetics can be fine-tuned by the 3D printing of specialized scaffold designs tailored for particular treatments while enhancing dosage effectiveness via localized sustained release. It has been challenging to establish scaffold properties as a function of fabrication parameters to obtain sustained release. In particular, the relationships between scaffold curing conditions, compressive strength, and drug release kinetics remain poorly understood. This study evaluates 3D printed scaffold formulation and feasibility to sustain the release of metronidazole, a commonly used antibiotic for BV. Cylindrical silicone scaffolds were printed and cured using three different conditions relevant to potential future incorporation of temperature-sensitive labile biologics. Compressive strength and drug release were monitored for 14d in simulated vaginal fluid to assess long-term effects of fabrication conditions on mechanical integrity and release kinetics. Scaffolds were mechanically evaluated to determine compressive and tensile strength, and elastic modulus. Release profiles were fitted to previous kinetic models to differentiate potential release mechanisms. The Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin models best described the release, indicating similarity to release from insoluble or polymeric matrices. This study shows the feasibility of 3D printed silicone scaffolds to provide sustained metronidazole release over 14d, with compressive strength and drug release kinetics tuned by the fabrication parameters.

Laponite-Based Nanocomposite Hydrogels for Drug Delivery Applications

Hydrogels are widely used for therapeutic delivery applications due to their biocompatibility, biodegradability, and ability to control release kinetics by tuning swelling and mechanical properties. However, their clinical utility is hampered by unfavorable pharmacokinetic properties, including high initial burst release and difficulty in achieving prolonged release, especially for small molecules (<500 Da). The incorporation of nanomaterials within hydrogels has emerged as viable option as a method to trap therapeutics within the hydrogel and sustain release kinetics. Specifically, two-dimensional nanosilicate particles offer a plethora of beneficial characteristics, including dually charged surfaces, degradability, and enhanced mechanical properties within hydrogels. The nanosilicate-hydrogel composite system offers benefits not obtainable by just one component, highlighting the need for detail characterization of these nanocomposite hydrogels. This review focuses on Laponite, a disc-shaped nanosilicate with diameter of 30 nm and thickness of 1 nm. The benefits of using Laponite within hydrogels are explored, as well as examples of Laponite-hydrogel composites currently being investigated for their ability to prolong the release of small molecules and macromolecules such as proteins. Future work will further characterize the interplay between nanosilicates, hydrogel polymer, and encapsulated therapeutics, and how each of these components affect release kinetics and mechanical properties.

Natural and Synthetic Clay Minerals in the Pharmaceutical and Biomedical Fields

Clay minerals are historically among the most used materials with a wide variety of applications. In pharmaceutical and biomedical fields, their healing properties have always been known and used in pelotherapy and therefore attractive for their potential. In recent decades, the research has therefore focused on the systematic investigation of these properties. This review aims to describe the most relevant and recent uses of clays in the pharmaceutical and biomedical field, especially for drug delivery and tissue engineering purposes. Clay minerals, which are biocompatible and non-toxic materials, can act as carriers for active ingredients while controlling their release and increasing their bioavailability. Moreover, the combination of clays and polymers is useful as it can improve the mechanical and thermal properties of polymers, as well as induce cell adhesion and proliferation. Different types of clays, both of natural (such as montmorillonite and halloysite) and synthetic origin (layered double hydroxides and zeolites), were considered in order to compare them and to assess their advantages and different uses.

Chitosan Hydrogels Cross-Linked with Trimesic Acid for the Delivery of 5-Fluorouracil in Cancer Therapy

Chitosan exhibits unique properties making it a suitable material for drug delivery. Considering the rising popularity of hydrogels in this field, this work offers a comprehensive study of hydrogels constituted by chitosan and cross-linked with 1,3,5-benzene tricarboxylic acid (BTC; also known as trimesic acid). Hydrogels were prepared by cross-linking chitosan with BTC in different concentrations. The nature of the gels was studied through oscillatory amplitude strain and frequency sweep tests within the linear viscoelastic region (LVE) limit. The flow curves of the gels revealed shear thinning behavior. High G′ values imply strong cross-linking with improved stability. The rheological tests revealed that the strength of the hydrogel network increased with the cross-linking degree. Hardness, cohesiveness, adhesiveness, compressibility, and elasticity of the gels were determined using a texture analyzer. The scanning electron microscopy (SEM) data of the cross-linked hydrogels showed distinctive pores with a pore size increasing according to increasing concentrations (pore size range between 3–18 µm). Computational analysis was performed by docking simulations between chitosan and BTC. Drug release studies employing 5-fluorouracil (5-FU) yielded a more sustained release profile with 35 to 50% release among the formulations studied in a 3 h period. Overall, this work demonstrated that the presence of BTC as cross-linker leads to satisfactory mechanical properties of the chitosan hydrogel, suggesting potential applications in the sustained release of cancer therapeutics.

Montmorillonite-Rifampicin Nanohybrid for pH-Responsive Release of the Tuberculostatic

The present work describes the development of a hybrid and pH-responsive system for rifampicin using the clay mineral 'montmorillonite' as a nanocarrier. The influence of operational variables on the drug incorporation process was evaluated using 2⁴ factorial designs. Under optimized conditions, the experiment allowed an incorporated drug dose equivalent to 98.60 ± 1.21 mg/g. Hybrid systems were characterized by different characterization techniques (FTIR, XRD, TGA, DSC, and SEM) to elucidate the mechanism of interaction between the compounds used. Through in vitro release studies, it was possible to verify the efficacy of the pH-dependent system obtained, with approximately 70% of the drug released after sixteen hours in simulated intestinal fluid. The adjustment of the experimental release data to the theoretical model of Higuchi and Korsmeyer-Peppas indicated that the release of rifampicin occurs in a prolonged form from montmorillonite. Elucidation of the interactions between the drug and this raw clay reinforces its viability as a novel carrier to develop an anti-TB/clay hybrid system with good physical and chemical stability.

Modified kaolin hydrogel for Cu2+ adsorption

Removal of Cu2+ ions from contaminated water is an important but challenging task. This study reports the synthesis of a composite hydrogel from two natural polysaccharides, namely, sodium alginate and chitosan, using inexpensive kaolin as a raw material and polyacrylamide as a modifier. The hydrogel had a high adsorption capacity and selectivity for Cu2+. The composite hydrogel was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The pseudo-second-order kinetic model was the most suitable model for the kinetic results, and the Langmuir isotherm model was the most representative of the sorption system. The results revealed that the adsorption process was mainly controlled by chemisorption. The maximum adsorption capacity of the adsorbent was 106.4 mg·g−1. Therefore, this study presents a new perspective on the application of composite hydrogels as Cu2+ adsorbents.

Synthesis and characterization of modified bioactive arabinoxylan-psyllium: Evaluation of molecular interactions, physiochemical and biomedical properties

Keeping in view the future prospectus of carbohydrate polymers, present research report is an elaboration, exploration and execution of the research expectancy in area of these polymers by researchers like John F. Kennedy. Herein, molecular interactions and physiochemical properties of modified bioactive arabinoxylan-psyllium have been evaluated for drug delivery applications. Arabinoxylan-psyllium was modified with sulphated and amide copolymers and co-polymers were characterized by SEMs, AFM, FTIR, XRD, solid state ¹³C NMR, TGA-DSC and water absorption studies. The ¹³C-NMR and FTIR confirmed grafted copolymers. The polymer-blood interactions revealed non-thrombogenic nature with thrombose percentage 63.17 ± 5.61 % and polymer-mucous membrane interactions showed detachment force 0.237 ± 0.078Nwith bio-membrane in mucoadhesion test. The pH responsible gels exhibited 44.49 ± 3.12 % inhibitions of free radicals in DPPH assay. The polymer-drug interactions demonstrated sustained diffusion of methotrexate with non-Fickian diffusion and Korsmeyer-Peppas kinetic model. Overall, co-polymeric network structure was found useful in colon specific drug delivery.

A novel pH-responsive nanoniosomal emulsion for sustained release of curcumin from a chitosan-based nanocarrier: emphasis on the concurrent improvement of loading, sustained release, and apoptosis induction

Curcumin application as an anti-cancer drug is faced with several impediments. This study has developed a platform that facilitates the sustained release of curcumin, improves loading efficiency, and anti-cancer activity. Montmorillonite (MMT) nanoparticles were added to chitosan (CS)-agarose (Aga) hydrogel and then loaded with curcumin (Cur) to prepare a curcumin-loaded nanocomposite hydrogel. The loading capacity increased from 63% to 76% by adding MMT nanoparticles to a chitosan-agarose hydrogel. Loading the fabricated nanocomposite in the nanoniosomal emulsion resulted in sustained release of curcumin under acidic conditions. Release kinetics analysis showed diffusion and erosion are the dominant release mechanisms, indicating non-fickian (or anomalous) transport based on the Korsmeyer-Peppas model. FTIR spectra confirmed that all nanocomposite components were present in the fabricated nanocomposite. Besides, XRD results corroborated the amorphous structure of the prepared nanocomposite. Zeta potential results corroborated the stability of the fabricated nanocarrier. Cytotoxicity of the prepared CS-Aga-MMT-Cur on MCF-7 cells was comparable to that of curcumin-treated cells (p <0.001). Moreover, the percentage of apoptotic cells increased due to the enhanced release profile resulting from the addition of MMT to the hydrogel and the incorporation of the fabricated nanocomposite into the nanoniosomal emulsion. To recapitulate, the current delivery platform improved loading, sustained release, and curcumin anti-cancer effect. Hence, this platform could be a potential candidate to mitigate cancer therapy restrictions with curcumin. This article is protected by copyright. All rights reserved.

Eu3+- and Tb3+-Based Coordination Complexes of Poly(N-Isopropyl,N-methylacrylamide-stat-N,N-dimethylacrylamide) Copolymer: Synthesis, Characterization and Property

This contribution reports the syntheses, structural analyses and properties of europium (Eu³⁺)- and terbium (Tb³⁺)-based coordination complexes of poly(N-isopropyl,N-methylacrylamide-stat-N,N-dimethylacrylamide) (poly(iPMAm-stat-DMAm)) copolymer, named as poly-Eu(III) and poly-Tb(III), respectively. In greater detail, poly(iPMAm₈₅-stat-DMAm₁₅) is first prepared by random copolymerization of N-isopropyl,N-methylacrylamide (iPMAm) and N,N-dimethylacrylamide (DMAm) via group transfer polymerization (GTP). Next, poly(iPMAm₈₅-stat-DMAm₁₅) is used as the polymer matrix for chelating with Eu³⁺ and Tb³⁺ cations at its side amide groups, to produce poly-Eu(III) and poly-Tb(III). Their structural characterizations by FT-IR spectroscopy and XPS confirm the formation of polymeric complexes. The study on their fluorescence emission characteristics and luminescence lifetime demonstrates that Poly-Eu(III) shows four strong emission peaks at 578, 593, 622, and 651 nm, which are responsible for the electron transitions from the excited ⁵D₀ state to the multiplet ⁷F_J (J = 0, 1, 2, 3) states, respectively, and poly-Tb(III) also displays four emission peaks at 489, 545, 588, and 654 nm, mainly due to the electron transitions of ⁵D₄ → ⁷F_i (i = 6, 5, 4, 3). The luminescence lifetimes of poly-Eu(III) (τ_poly-Eu(III)) and poly-Tb(III) (τ_poly-Tb(III)) are determined to be 4.57 and 7.50 ms, respectively. In addition, in aqueous solutions, poly-Eu(III) and poly-Tb(III) are found to exhibit thermoresponsivity, with their cloud temperatures (T_cs) locating around 36.4 and 36.8 °C, respectively. Finally, the cytotoxicity study on the human colon carcinoma cells LoVo and DLD1 suggests that the luminescent Eu³⁺ and Tb³⁺ in the chelated state with poly(iPMAm-stat-DMAm) show much better biocompatibility and lower toxicity than their inorganic salts.

Recent progress in advanced biomaterials for long-acting reversible contraception

Unintended pregnancy is a global issue with serious ramifications for women, their families, and society, including abortion, infertility, and maternal death. Although existing contraceptive strategies have been widely used in people's lives, there have not been satisfactory feedbacks due to low contraceptive efficacy and related side effects (e.g., decreased sexuality, menstrual cycle disorder, and even lifelong infertility). In recent years, biomaterials-based long-acting reversible contraception has received increasing attention from the viewpoint of fundamental research and practical applications mainly owing to improved delivery routes and controlled drug delivery. This review summarizes recent progress in advanced biomaterials for long-acting reversible contraception via various delivery routes, including subcutaneous implant, transdermal patch, oral administration, vaginal ring, intrauterine device, fallopian tube occlusion, vas deferens contraception, and Intravenous administration. In addition, biomaterials, especially nanomaterials, still need to be improved and prospects for the future in contraception are mentioned.

Calcium montmorillonite as potential carrier in release of bisphosphonates

There is a strong need to search for more effective bisphosphonates carriers which will lead to increased bioavailability of bone tissue engineering. Montmorillonite and calcium montmorillonite were used as risedronate...

A tough synthetic hydrogel with excellent post-loading of drugs for promoting the healing of infected wounds in vivo

Bacterial infection is a major obstacle to the wound healing process. The hydrogel dressings with a simpler structure and good antibacterial and wound healing performance are appealing for clinical application. Herein, a robust hydrogel was synthesized from acrylamide (AM), acrylic acid (AA) and N,N'-methylene diacrylamide (MBA) via a redox initiating polymerization. The polymerization conditions were optimized to obtain the hydrogel with minimum unreacted monomers, which were 0.25% and 0.12% for AM and AA, respectively. The hydrogel had good mechanical strength, and could effectively resist damage by external forces and maintain a good macroscopic shape. It showed large water uptake capacity, and could post load a wide range of molecules via hydrogen bonding and electrostatic interaction. Loading of antibiotic doxycycline (DOX) enabled the hydrogel with good antibacterial activity against both Gram-positive bacteria and Gram-negative bacteria in vitro and in vivo. In a rat model of methicillin-resistant Staphylococcus aureus (MRSA)-infected full-thickness skin defect wound, the DOX-loaded hydrogel showed good therapeutic effect. It could significantly promote the wound closure, increased the collagen coverage area, down-regulate the expressions of pro-inflammatory TNF-α and IL-1β factors, and up-regulate the expressions of anti-inflammatory IL-4 factor and CD31 neovascularization factor.

Erythrocyte-mimicking subcutaneous platform with a laser-controlled treatment against diabetes

Exogenous insulin (INS) is critical for managing diabetes. However, owing to its short in vivo half-life, frequent injection of INS is un-avoidable, which is both painful and inconvenient, compromising the quality of life. Herein, we developed a laser-regulated INS release system (INS-ICG@ER hydrogel) that allowed an on-demand release of INS from the subcutaneous INS reservoir by remote laser control without the frequent injection of INS. The amino acid hydrogel functions as a hydrogel 3D scaffold material, which offers increased subcutaneous stability of drug loaded erythrocytes (ER). This INS-ICG@ER hydrogel would release INS due to the elevated content of reactive oxygen species (ROS), generated by ICG under laser irritation. Conversely, the ROS would be scavenged without the laser irradiation and stopped the release of INS from INS-ICG@ER hydrogel. Furthermore, the release of INS from INS-ICG@ER hydrogel could be regulated by laser irradiation. The INS-ICG@ER hydrogels could control the hyperglycemia within 2 h in diabetic mice and maintained their normal blood glucose level (BGL) for up to 6 days with laser irradiation 30 min prior to meals avoiding the frequent injection of free INS. This delivery system is an effective method that offers a spatiotemporally controlled release of INS to control the glucose level in vivo.

Preparation of Chitosan/Calcium Alginate/Bentonite Composite Hydrogel and Its Heavy Metal Ions Adsorption Properties

In order to avoid the secondary pollution of the toxic residue of chemical crosslinking agent accompanied by chemical hydrogel adsorbent and enhance the adsorption performance of physical hydrogel, chitosan/calcium alginate/bentonite (CTS/CA/BT) composite physical hydrogel was constructed. The formation mechanism and structure of the composite hydrogel were determined by FTIR, XRD and SEM. Adsorption performances of the hydrogel toward Pb2+, Cu2+ and Cd2+ in water under different condition as well as multi-ion competitive sorption were investigated. The adsorption processes were described with the canonical adsorption kinetics and isotherms models. With the utilization of XPS analysis and adsorption thermodynamics analysis, it was found that the adsorptions were spontaneous physico-chemical adsorptions. The results showed that the maximum adsorption capacity of the hydrogel for Pb2+, Cu2+ and Cd2+ reached up to 434.89, 115.30 and 102.38 mg·g-1, respectively, better than those of other physical hydrogels or chitosan/bentonite composite. Moreover, the composite hydrogel improved the collectability of bentonite and showed a good reusability. The modification of bentonite and the formation of hydrogel were completed simultaneously, which greatly simplifies the operation process compared with the prior similar works. These suggest that the CTS/CA/BT composite hydrogel has promising application prospects for removal of heavy metal ions from water.

Magnetic κ-carrageenan/chitosan/montmorillonite nanocomposite hydrogels with controlled sunitinib release

This work aimed to design montmorillonite-incorporated pH-responsive and magnetic κ-carrageenan/chitosan hydrogels via a completely green route for controlled release of sunitinib anticancer drug. This was accomplished by ionic cross-linking of two biopolymers, κ-carrageenan and chitosan, in the presence of magnetic montmorillonite (mMMt) nanoplatelets. Interestingly, it was observed that the amount of mMMt affected not only the microstructure of hydrogels, but also the drug loading efficiency of nanocomposite hydrogels was noticeably increased by introducing mMMt (from 69 to 96%). The in vitro sunitinib release experiments showed that a low content of loaded sunitinib was released from all hydrogels in the buffered solution with pH 7.4. In contrast, a relatively sustained release with a high content of drug release was observed in the acidic solution of pH 5.5. During 48 h, the hydrogels nanocomposite containing a high content of mMMt showed cumulative release of 64.0 and 8.6% at pH 5.5 and 7.4, respectively. During two days, while the cumulative release of sunitinib was obtained 84.3% for the magnetic-free hydrogel, the magnetic ones showed 74.4 and 64% with the low and high contents of magnetic MMt, respectively. The developed κ-carrageenan/chitosan hydrogels with a high capacity of drug loading and subsequent pH-sensitive drug release can be considered in prolonged cancer therapy with reduced side effects.

Highlights in poloxamer-based drug delivery systems as strategy at local application for vaginal infections

Infectious diseases related to the vagina include diseases caused by the imbalance of the vaginal flora and by sexually transmitted infections. Some of these present themselves as a public health problem due to the lack of efficient treatment that leads to their complete cure, and others due to the growing resistance to drugs used in therapy. In this sense, new treatment strategies are desirable, with vaginal administration rout being a great choice since can bypass first-pass metabolism and decrease drug interactions and adverse effects. However, it is worth highlighting limitations related to patient's discomfort at application time. Thereby, the use of poloxamer-based drug delivery systems is desirable due its stimuli-sensitive characteristic. Therefore, the present review reports a brief overview of poloxamer properties, biological behavior and advances in poloxamer applications in controlled drug release systems for infectious diseases related to the vagina treatment and prevention.

Niclosamide-Clay Intercalate Coated with Nonionic Polymer for Enhanced Bioavailability toward COVID-19 Treatment

Niclosamide (NIC), a conventional anthelmintic agent, is emerging as a repurposed drug for COVID-19 treatment. However, the clinical efficacy is very limited due to its low oral bioavailability resulting from its poor aqueous solubility. In the present study, a new hybrid drug delivery system made of NIC, montmorillonite (MMT), and Tween 60 is proposed to overcome this obstacle. At first, NIC molecules were immobilized into the interlayer space of cationic clay, MMT, to form NIC–MMT hybrids, which could enhance the solubility of NIC, and then the polymer surfactant, Tween 60, was further coated on the external surface of NIC–MMT to improve the release rate and the solubility of NIC and eventually the bioavailability under gastrointestinal condition when orally administered. Finally, we have performed an in vivo pharmacokinetic study to compare the oral bioavailability of NIC for the Tween 60-coated NIC–MMT hybrid with Yomesan^®, which is a commercially available NIC. Exceptionally, the Tween 60-coated NIC–MMT hybrid showed higher systemic exposure of NIC than Yomesan^®. Therefore, the present NIC–MMT–Tween 60 hybrid can be a potent NIC drug formulation with enhanced solubility and bioavailability in vivo for treating Covid-19.

Evolution of drug-eluting biomedical implants for sustained drug delivery

In the field of drug delivery, the most commonly used treatments have traditionally been systemically delivered using oral or intravenous administration. The problems associated with this type of delivery is that the drug concentration is controlled by first pass metabolism, and therefore may not always remain within the therapeutic window. Implantable drug delivery systems (IDDSs) are an excellent alternative to traditional delivery because they offer the ability to precisely control the drug release, deliver drugs locally to the target tissue, and avoid the toxic side effects often experienced with systemic administration. Since the creation of the first FDA-approved IDDS in 1990, there has been a surge in research devoted to fabricating and testing novel IDDS formulations. The versatility of these systems is evident when looking at the various biomedical applications that utilize IDDSs. This review provides an overview of the history of IDDSs, with examples of the different types of IDDS formulations, as well as looking at current and future biomedical applications for such systems. Though there are still obstacles that need to be overcome, ever-emerging new technologies are making the manufacturing of IDDSs a rewarding therapeutic endeavor with potential for further improvements.

Vaginal Administration of Contraceptives

While contraceptive drugs have enabled many people to decide when they want to have a baby, more than 100 million unintended pregnancies each year in the world may indicate the contraceptive requirement of many people has not been well addressed yet. The vagina is a well-established and practical route for the delivery of various pharmacological molecules, including contraceptives. This review aims to present an overview of different contraceptive methods focusing on the vaginal route of delivery for contraceptives, including current developments, discussing the potentials and limitations of the modern methods, designs, and how well each method performs for delivering the contraceptives and preventing pregnancy.

An effective vaginal gel to deliver CRISPR/Cas9 system encapsulated in poly (β-amino ester) nanoparticles for vaginal gene therapy

BACKGROUND

Gene therapy has held promises for treating specific genetic diseases. However, the key to clinical application depends on effective gene delivery.

METHODS

Using a large animal model, we developed two pharmaceutical formulations for gene delivery in the pigs' vagina, which were made up of poly (β-amino ester) (PBAE)-plasmid polyplex nanoparticles (NPs) based two gel materials, modified montmorillonite (mMMT) and hectorite (HTT).

FINDINGS

By conducting flow cytometry of the cervical cells, we found that PBAE-GFP-NPs-mMMT gel was more efficient than PBAE-GFP-NPs-HTT gel in delivering exogenous DNA intravaginally. Next, we designed specific CRISPR/SpCas9 sgRNAs targeting porcine endogenous retroviruses (PERVs) and evaluated the genome editing efficacy in vivo. We discovered that PERV copy number in vaginal epithelium could be significantly reduced by the local delivery of the PBAE-SpCas9/sgRNA NPs-mMMT gel. Comparable genome editing results were also obtained by high-fidelity version of SpCas9, SpCas9-HF1 and eSpCas9, in the mMMT gel. Further, we confirmed that the expression of topically delivered SpCas9 was limited to the vagina/cervix and did not diffuse to nearby organs, which was relatively safe with low toxicity.

INTERPRETATION

Our data suggested that the PBAE-NPs mMMT vaginal gel is an effective preparation for local gene therapy, yielding insights into novel therapeutic approaches to sexually transmitted disease in the genital tract.

FUNDING

This work was supported by the National Science and Technology Major Project of the Ministry of science and technology of China (No. 2018ZX10301402); the National Natural Science Foundation of China (81761148025, 81871473 and 81402158); Guangzhou Science and Technology Programme (No. 201704020093); National Ten Thousand Plan-Young Top Talents of China, Fundamental Research Funds for the Central Universities (17ykzd15 and 19ykyjs07); Three Big Constructions-Supercomputing Application Cultivation Projects sponsored by National Supercomputer Center In Guangzhou; the National Research FFoundation (NRF) South Africa under BRICS Multilateral Joint Call for Proposals; grant 17-54-80078 from the Russian Foundation for Basic Research.