DNA-Based Hybrid Hydrogels Sustain Water-Insoluble Ophthalmic Therapeutic Delivery against Allergic Conjunctivitis

Developing hydrogels for gene therapy and tissue engineering

Hydrogels are a class of highly absorbent and easily modified polymer materials suitable for use as slow-release carriers for drugs. Gene therapy is highly specific and can overcome the limitations of traditional tissue engineering techniques and has significant advantages in tissue repair. However, therapeutic genes are often affected by cellular barriers and enzyme sensitivity, and carrier loading of therapeutic genes is essential. Therapeutic gene hydrogels can well overcome these difficulties. Moreover, gene-therapeutic hydrogels have made considerable progress. This review summarizes the recent research on carrier gene hydrogels for the treatment of tissue damage through a summary of the most current research frontiers. We initially introduce the classification of hydrogels and their cross-linking methods, followed by a detailed overview of the types and modifications of therapeutic genes, a detailed discussion on the loading of therapeutic genes in hydrogels and their characterization features, a summary of the design of hydrogels for therapeutic gene release, and an overview of their applications in tissue engineering. Finally, we provide comments and look forward to the shortcomings and future directions of hydrogels for gene therapy. We hope that this article will provide researchers in related fields with more comprehensive and systematic strategies for tissue engineering repair and further promote the development of the field of hydrogels for gene therapy.

Advancements in Regenerative Hydrogels in Skin Wound Treatment: A Comprehensive Review

This state-of-the-art review explores the emerging field of regenerative hydrogels and their profound impact on the treatment of skin wounds. Regenerative hydrogels, composed mainly of water-absorbing polymers, have garnered attention in wound healing, particularly for skin wounds. Their unique properties make them well suited for tissue regeneration. Notable benefits include excellent water retention, creating a crucially moist wound environment for optimal healing, and facilitating cell migration, and proliferation. Biocompatibility is a key feature, minimizing adverse reactions and promoting the natural healing process. Acting as a supportive scaffold for cell growth, hydrogels mimic the extracellular matrix, aiding the attachment and proliferation of cells like fibroblasts and keratinocytes. Engineered for controlled drug release, hydrogels enhance wound healing by promoting angiogenesis, reducing inflammation, and preventing infection. The demonstrated acceleration of the wound healing process, particularly beneficial for chronic or impaired healing wounds, adds to their appeal. Easy application and conformity to various wound shapes make hydrogels practical, including in irregular or challenging areas. Scar minimization through tissue regeneration is crucial, especially in cosmetic and functional regions. Hydrogels contribute to pain management by creating a protective barrier, reducing friction, and fostering a soothing environment. Some hydrogels, with inherent antimicrobial properties, aid in infection prevention, which is a crucial aspect of successful wound healing. Their flexibility and ability to conform to wound contours ensure optimal tissue contact, enhancing overall treatment effectiveness. In summary, regenerative hydrogels present a promising approach for improving skin wound healing outcomes across diverse clinical scenarios. This review provides a comprehensive analysis of the benefits, mechanisms, and challenges associated with the use of regenerative hydrogels in the treatment of skin wounds. In this review, the authors likely delve into the application of rational design principles to enhance the efficacy and performance of hydrogels in promoting wound healing. Through an exploration of various methodologies and approaches, this paper is poised to highlight how these principles have been instrumental in refining the design of hydrogels, potentially revolutionizing their therapeutic potential in addressing skin wounds. By synthesizing current knowledge and highlighting potential avenues for future research, this review aims to contribute to the advancement of regenerative medicine and ultimately improve clinical outcomes for patients with skin wounds.

Evolution of Hybrid Hydrogels: Next-Generation Biomaterials for Drug Delivery and Tissue Engineering

Hydrogels, being hydrophilic polymer networks capable of absorbing and retaining aqueous fluids, hold significant promise in biomedical applications owing to their high water content, permeability, and structural similarity to the extracellular matrix. Recent chemical advancements have bolstered their versatility, facilitating the integration of the molecules guiding cellular activities and enabling their controlled activation under time constraints. However, conventional synthetic hydrogels suffer from inherent weaknesses such as heterogeneity and network imperfections, which adversely affect their mechanical properties, diffusion rates, and biological activity. In response to these challenges, hybrid hydrogels have emerged, aiming to enhance their strength, drug release efficiency, and therapeutic effectiveness. These hybrid hydrogels, featuring improved formulations, are tailored for controlled drug release and tissue regeneration across both soft and hard tissues. The scientific community has increasingly recognized the versatile characteristics of hybrid hydrogels, particularly in the biomedical sector. This comprehensive review delves into recent advancements in hybrid hydrogel systems, covering the diverse types, modification strategies, and the integration of nano/microstructures. The discussion includes innovative fabrication techniques such as click reactions, 3D printing, and photopatterning alongside the elucidation of the release mechanisms of bioactive molecules. By addressing challenges, the review underscores diverse biomedical applications and envisages a promising future for hybrid hydrogels across various domains in the biomedical field.

DNA Adjuvant Hydrogel-Optimized Enzymatic Cascade Reaction for Tumor Chemodynamic-Immunotherapy

Chemodynamic therapy (CDT) shows immense potential in cancer treatment as it not only directly kills tumor cells but also induces anti-tumor immune responses. However, the efficacy of CDT is hampered by challenges in targeting CDT catalysts specifically to tumors using nanomaterials, along with the limitations of low H2 O2 levels and short catalyst duration within the tumor microenvironment. In this study, DNA adjuvant hydrogel to arrange a glucose oxidase-ferrocene cascade for continuously generating reactive oxygen species (ROS) from glucose in situ for tumor CDT combined with immunotherapy is employed. By precisely tuning the catalyst spacing with DNA double helix, ROS production efficiency is elevated by up to nine times compared to free catalysts, resulting in stronger immunogenetic cell death. Upon intratumoral injection, the DNA hydrogel system elicited potent anti-tumor immune responses, thereby effectively inhibiting established tumors and rejecting re-challenged tumors. This work offers a novel platform for integrated CDT and immunotherapy in cancer treatment.

Rational Design of DNA Hydrogels Based on Molecular Dynamics of Polymers

In recent years, DNA has emerged as a fascinating building material to engineer hydrogel due to its excellent programmability, which has gained considerable attention in biomedical applications. Understanding the structure-property relationship and underlying molecular determinants of DNA hydrogel is essential to precisely tailor its macroscopic properties at molecular level. In this review, the rational design principles of DNA molecular networks based on molecular dynamics of polymers on the temporal scale, which can be engineered via the backbone rigidity and crosslinking kinetics, are highlighted. By elucidating the underlying molecular mechanisms and theories, it is aimed to provide a comprehensive overview of how the tunable DNA backbone rigidity and the crosslinking kinetics lead to desirable macroscopic properties of DNA hydrogels, including mechanical properties, diffusive permeability, swelling behaviors, and dynamic features. Furthermore, it is also discussed how the tunable macroscopic properties make DNA hydrogels promising candidates for biomedical applications, such as cell culture, tissue engineering, bio-sensing, and drug delivery.

Stimulus-Responsive Hydrogels as Drug Delivery Systems for Inflammation Targeted Therapy

Deregulated inflammations induced by various factors are one of the most common diseases in people's daily life, while severe inflammation can even lead to death. Thus, the efficient treatment of inflammation has always been the hot topic in the research of medicine. In the past decades, as a potential biomaterial, stimuli-responsive hydrogels have been a focus of attention for the inflammation treatment due to their excellent biocompatibility and design flexibility. Recently, thanks to the rapid development of nanotechnology and material science, more and more efforts have been made to develop safer, more personal and more effective hydrogels for the therapy of some frequent but tough inflammations such as sepsis, rheumatoid arthritis, osteoarthritis, periodontitis, and ulcerative colitis. Herein, from recent studies and articles, the conventional and emerging hydrogels in the delivery of anti-inflammatory drugs and the therapy for various inflammations are summarized. And their prospects of clinical translation and future development are also discussed in further detail.

Dendritic Oligoethylenimine Decorated Liposome with Augmented Corneal Retention and Permeation for Efficient Topical Delivery of Antiglaucoma Drugs

The topically administered glaucoma medications usually encounter serious precorneal drug loss and low corneal penetration, leading to a low bioavailability. In addition, due to the complexity of glaucoma etiology, a single medication is often insufficient. In this work, we report a novel dendritic oligoethylenimine decorated liposome for codelivery of two antiglaucoma drugs, latanoprost and timolol. The liposome showed a uniform nanoscopic particle size, positive surface charge, and excellent dual-drug loading capacity. A prolonged precorneal retention is observed by using this liposomal delivery system. This liposomal delivery system presents increased cellular uptake and tight junctions opening capacity, contributing respectively to the transcellular and paracellular permeation, thereby enhancing the trans-corneal transportation. Following topical administration of one eye drop in brown Norway rats, the dual-drug-loaded liposome formulation resulted in a sustained and effective intraocular pressure reduction as long as 5 days, without inducing ocular inflammation, discomfort, and tissue damage.

Inhibition of IKKβ via a DNA-Based In Situ Delivery System Improves Achilles Tendinopathy Healing in a Rat Model

BACKGROUND

The inhibition of IKKβ by the inhibitor 2-amino-6-[2-(cyclopropylmethoxy)-6-hydroxyphenyl]-4-(4-piperidinyl)-3-pyridine carbonitrile (ACHP) is a promising strategy for the treatment of Achilles tendinopathy. However, the poor water solubility of ACHP severely hinders its in vivo application. Moreover, the effective local delivery of ACHP to the tendon and its therapeutic effects have not been reported.

PURPOSE

To investigate the therapeutic effects of IKKβ inhibition via injection of ACHP incorporated into a DNA supramolecular hydrogel in a collagenase-induced tendinopathy rat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Dendritic DNA, a Y-shaped monomer, and a crosslinking monomer were mixed with ACHP and self-assembled into an ACHP-DNA supramolecular hydrogel (ACHP-Gel). The effects of ACHP-Gel in tendon stem/progenitor cells were investigated via RNA sequencing and validated using quantitative reverse transcription polymerase chain reaction (qRT-PCR). A total of 120 collagenase-induced rats were randomly assigned to 5 groups: blank, phosphate-buffered saline (PBS), DNA-Gel, ACHP, and ACHP-Gel. Healing outcomes were evaluated using biomechanic and histologic evaluations at 4 and 8 weeks.

RESULTS

ACHP-Gel enhanced the solubility of ACHP and sustained its release for ≥21 days in vivo, which significantly increased the retention time of ACHP and markedly reduced the frequency of administration. RNA sequencing and qRT-PCR showed that ACHP effectively downregulated genes related to inflammation and extracellular matrix remodeling and upregulated genes related to tenogenic differentiation. The cross-sectional area (P = .024), load to failure (P = .002), stiffness (P = .039), and elastic modulus (P = .048) significantly differed between the ACHP-Gel and PBS groups at 8 weeks. The ACHP-Gel group had better histologic scores than the ACHP group at 4 (P = .042) and 8 weeks (P = .009). Type I collagen expression (COL-I; P = .034) and the COL-I/collagen type III ratio (P = .015) increased while interleukin 6 expression decreased (P < .001) in the ACHP-Gel group compared with the ACHP group at 8 weeks.

CONCLUSION

DNA supramolecular hydrogel significantly enhanced the aqueous solubility of ACHP and increased its release-retention time. Injection frequency was markedly reduced. ACHP-Gel suppressed inflammation in Achilles tendinopathy and promoted tendon healing in a rat model.

CLINICAL RELEVANCE

ACHP-Gel injection is a promising strategy for the treatment of Achilles tendinopathy in clinical practice.

DNA-Based Hydrogels with Multidrug Sequential Release for Promoting Diabetic Wound Regeneration

Diabetic wound (DW) regeneration is highly challenging due to persistent bacterial infection, excessive production of reactive oxygen species (ROS), prolonged inflammatory response, and insufficient angiogenesis. Ideal management requires the integration and sequential release of bactericidal, antioxidative, anti-inflammatory, and angiogenic agents during DW repair. Here, we develop a DNA-based multidrug hydrogel, termed Agilegel, to promote the efficient healing of DW. Hierarchically structured Agilegel can precisely control the sequential release of vascular endothelial growth factor-alpha (VEGF-α), silver nanoclusters (AgNCs), and interleukin-10 (IL-10) through covalent bonds in its primary structure (phosphate backbone), noncovalent bonds in its secondary structure (base pairs), and physical encapsulation in its advanced structure (pores), respectively. We demonstrate that Agilegel can effectively eliminate bacterial infection through AgNCs and mitigate ROS production through DNA scaffolds. Moreover, during the inflammatory phase, Agilegel promotes the polarization of macrophages from pro-inflammatory M1 to anti-inflammatory M2 phenotype using IL-10. Subsequently, Agilegel stimulates cell proliferation, angiogenesis, and extracellular matrix formation through the action of VEGF-α, thereby accelerating the closure of DW. Our results indicate that DNA hydrogels confer the capacity to regulate the sequential release of drugs, enabling them to effectively manage the phased intervention of multiple drugs in the treatment of complex diseases within physiological environments.

Programmable DNA Hydrogel Provides Suitable Microenvironment for Enhancing TSPCS Therapy in Healing of Tendinopathy

Tendon stem/progenitor cells (TSPCs) therapy is a promising strategy for enhancing cell matrix and collagen synthesis, and regulating the metabolism of the tendon microenvironment during tendon injury repair. Nevertheless, the barren microenvironment and gliding shear of tendon cause insufficient nutrition supply, damage, and aggregation of injected TSPCs around tendon tissues, which severely hinders their clinical application in tendinopathy. In this study, a TSPCs delivery system is developed by encapsulating TSPCs within a DNA hydrogel (TSPCs-Gel) as the DNA hydrogel offers an excellent artificial extracellular matrix (ECM) microenvironment by providing nutrition for proliferation and protection against shear forces. This delivery method restricts TSPCs to the tendons, significantly extending their retention time. It is also found that TSPCs-Gel injections can promote the healing of rat tendinopathy in vivo, where cross-sectional area and load to failure of injured tendons in rats are significantly improved compared to the free TSPCs treatment group at 8 weeks. Furthermore, the potential healing mechanism of TSPCs-Gel is investigated by RNA-sequencing to identify a series of potential gene and signaling pathway targets for further clinical treatment strategies. These findings suggest the potential pathways of using DNA hydrogels as artificial ECMs to promote cell proliferation and protect TSPCs in TSPC therapy.

Applications of Functional DNA Materials in Immunomodulatory Therapy

In recent years, nanoscale or microscale functional materials derived from DNA have shown great potential for immunotherapy as superior delivery carriers. DNA nanostructures with excellent programmability and addressability enable the precise assembly of molecules or nanoparticles. DNA hydrogels have predictable structures and adjustable mechanical strength, thus being advantageous in controllable release of cargos. In addition, utilizing systematic evolution of ligands by exponential enrichment technology, a variety of DNA aptamers have been screened for specific recognition of ions, molecules, and even cells. Moreover, a wide variety of chemical modifications can further enrich the function of DNA. The unique advantages of functional DNA materials make them extremely attractive in immunomodulation. Recently, functional DNA materials-based immunotherapy has shown great potential in fighting against many diseases like cancer, viral infection, and inflammation. Therefore, in this review, we focus on discussing the progress of the applications of functional DNA materials in immunotherapy; before that, we also summarize the characteristics of the functional DNA materials descried above. Finally, we discuss the challenges and future opportunities of functional DNA materials in immunomodulatory therapy.

Injectable DNA Hydrogel-Based Local Drug Delivery and Immunotherapy

Regulated drug delivery is an important direction in the field of medicine and healthcare research. In recent years, injectable hydrogels with good biocompatibility and biodegradability have attracted extensive attention due to their promising application in controlled drug release. Among them, DNA hydrogel has shown great potentials in local drug delivery and immunotherapy. DNA hydrogel is a three-dimensional network formed by cross-linking of hydrophilic DNA strands with extremely good biocompatibility. Benefiting from the special properties of DNA, including editable sequence and specificity of hybridization reactions, the mechanical properties and functions of DNA hydrogels can be precisely designed according to specific applications. In addition, other functional materials, including peptides, proteins and synthetic organic polymers can be easily integrated with DNA hydrogels, thereby enriching the functions of the hydrogels. In this review, we first summarize the types and synthesis methods of DNA hydrogels, and then review the recent research progress of injectable DNA hydrogels in local drug delivery, especially in immunotherapy. Finally, we discuss the challenges facing DNA hydrogels and future development directions.

Physically Cross-Linked DNA Hydrogel-Based Sustained Cytokine Delivery for In Situ Diabetic Alveolar Bone Rebuilding

The development of a biodegradable and shape-adaptable bioscaffold that can enhance local cytokine retention and bioactivity is essential for the application of immunotherapy in periodontal diseases. Here, we report a biodegradable, anti-inflammatory, and osteogenic ILGel that uses a physically cross-linked DNA hydrogel as a soft bioscaffold for the long-term sustained release of cytokine interleukin-10 (IL-10) to accelerate diabetic alveolar bone rebuilding. Porous microstructures of ILGel favored the encapsulation of IL-10 and maintained IL-10 bioactivity for at least 7 days. ILGel can be gradually degraded or hydrolyzed under physiological conditions, avoiding the potential undesired side effects on dental tissues. Long-term sustained release of bioactive IL-10 from ILGel not only promoted M2 macrophage polarization and attenuated periodontal inflammation but also triggered osteogenesis of mesenchymal stem cells (MSCs), leading to accelerated alveolar bone formation and healing of alveolar bone defects under diabetic conditions in vivo. ILGel treatment significantly accelerated the defect healing rate of diabetic alveolar injury up to 93.42 ± 4.6% on day 21 post treatment compared to that of free IL-10 treatment (63.30 ± 7.39%), with improved trabecular architectures. Our findings imply the potential application of the DNA hydrogel as the bioscaffold for cytokine-based immunotherapy in diabetic alveolar bone injury and other periodontal diseases.

Ovalbumin-Induced Allergic Inflammation Diminishes Cross-Linked Collagen Structures in an Experimental Rabbit Model of Corneal Cross-Linking

Background

Allergic conjunctivitis (AC) is one of the reported potential risk factors of progression in keratoconus patients after corneal cross-linking surgery; however, the causal relationship is still inconclusive. Recent studies have indicated that various inflammatory cytokines play a vital role in the development of primary keratoconus. It is still unclear whether these inflammatory mediators also trigger CXL failures. This study aimed to investigate the impact of AC on the rabbit corneas after trans-epithelial corneal cross-linking (TCXL).

Methods

A total of six rabbits were kept untreated as the normal control (NC) group. A total of 18 rabbits were treated by TCXL and divided into three groups (six in each group), namely, no treatment (TCXL group); induction of AC (TCXL + AC group); and induction of AC plus topical prednisolone acetate (TCXL + AC + PA group), according to additional treatment. AC was induced by topical application of ovalbumin after intraperitoneal pre-sensitization with ovalbumin. Rabbits were evaluated by slit lamp, in vivo laser scanning confocal microscopy, anterior segment optical coherence tomography, and measurement of corneal biomechanics. The cornea specimens were collected for the transmission electron microscope, the collagenase I digestion test, and PCR assay for TNF-α, IL-6, IL-1β, matrix metalloproteinase 9 (MMP-9), lysyl oxidase (LOX), and tissue inhibitor of metalloproteinases 1 (TIMP-1) on the day (D) 28.

Results

On D28, the TNF-α, IL-6, IL-1β, MMP-9, and LOX levels were significantly increased while the TIMP-1 was decreased in the TCXL + AC group when compared with the TCXL and TCXL + AC + PA groups. In vivo confocal microscopy revealed that at a depth of 150–210 μm, a trabecular patterned hyperdense structure surrounded by elongated needle-like processes could be observed in the TCXL and TCXL + AC + PA groups, but hardly seen in the TCXL + AC group. The demarcation lines were indistinct and blurred in the TCXL + AC group. An electron microscope demonstrated less interlacing fibril lamellae and higher interfibrillar spacing in the TCXL + AC group. The stability of corneal biomechanics and resistance to collagenase were decreased in the TCXL + AC group.

Conclusion

The corneal microstructures induced by TCXL and biomechanical stability were diminished in rabbits with AC but could be maintained by topical anti-inflammatory treatment. Our results supported the causal relationship between altered cytokine profiles and corneal microstructure after primary corneal cross-linking.

Ocular Nanomedicine

Intrinsic shortcomings associated with conventional therapeutic strategies often compromise treatment efficacy in clinical ophthalmology, prompting the rapid development of versatile alternatives for satisfactory diagnostics and therapeutics. Given advances in material science, nanochemistry, and nanobiotechnology, a broad spectrum of functional nanosystems has been explored to satisfy the extensive requirements of ophthalmologic applications. In the present review, the recent progress in nanosystems, both conventional and emerging nanomaterials in ophthalmology from state-of-the-art studies, are comprehensively examined and the role of their fundamental physicochemical properties in bioavailability, tissue penetration, biodistribution, and elimination after interacting with the ophthalmologic microenvironment emphasized. Furthermore, along with the development of surface engineering of nanomaterials, emerging theranostic methodologies are promoted as potential alternatives for multipurpose ocular applications, such as emerging biomimetic ophthalmology (e.g., smart electrochemical eye), thus provoking a holistic review of "ocular nanomedicine." By affording insight into challenges encountered by ocular nanomedicine and further highlighting the direction of future studies, this review provides an incentive for enriching ocular nanomedicine-based fundamental research and future clinical translation.

Drug Delivery Strategies and Biomedical Significance of Hydrogels: Translational Considerations

Hydrogels are a promising and attractive option as polymeric gel networks, which have immensely fascinated researchers across the globe because of their outstanding characteristics such as elevated swellability, the permeability of oxygen at a high rate, good biocompatibility, easy loading, and drug release. Hydrogels have been extensively used for several purposes in the biomedical sector using versatile polymers of synthetic and natural origin. This review focuses on functional polymeric materials for the fabrication of hydrogels, evaluation of different parameters of biocompatibility and stability, and their application as carriers for drugs delivery, tissue engineering and other therapeutic purposes. The outcome of various studies on the use of hydrogels in different segments and how they have been appropriately altered in numerous ways to attain the desired targeted delivery of therapeutic agents is summarized. Patents and clinical trials conducted on hydrogel-based products, along with scale-up translation, are also mentioned in detail. Finally, the potential of the hydrogel in the biomedical sector is discussed, along with its further possibilities for improvement for the development of sophisticated smart hydrogels with pivotal biomedical functions.

XT-type DNA hydrogels loaded with VEGF and NGF promote peripheral nerve regeneration via a biphasic release profile

Peripheral nerve injury (PNI) remains an unresolved challenge in the medicine area. With the development of biomaterial science and tissue engineering, a variety of nerve conduits were widely applied for repairing long defect PNI. DNA materials are developing rapidly due to their multiple advantages. In the present study, we aim to combine a DNA hydrogel, vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) to construct a new type of delivery system, which could achieve a biphasic release profile of VEGF and NGF by taking advantage of the different degradation rates between X- and T-type DNA. In vitro results showed that the DNA gel + VEGF/NGF system could promote proliferation, migration and myelination of Rat Schwann cells (RSC) while maintaining cell viability. In vivo results indicated a better effect of DNA gel + VEGF/NGF on promoting repair of long defect PNI than the hollow chitin conduits (CT), DNA gel or VEGF/NGF group. The new technology invention holds promising clinical application prospects for repairing PNI and may be used broadly after step-by-step improvement.

Harnessing the physicochemical properties of DNA as a multifunctional biomaterial for biomedical and other applications

The biological purpose of DNA is to store, replicate, and convey genetic information in cells. Progress in molecular genetics have led to its widespread applications in gene editing, gene therapy, and forensic science. However, in addition to its role as a genetic material, DNA has also emerged as a nongenetic, generic material for diverse biomedical applications. DNA is essentially a natural biopolymer that can be precisely programed by simple chemical modifications to construct materials with desired mechanical, biological, and structural properties. This review critically deciphers the chemical tools and strategies that are currently being employed to harness the nongenetic functions of DNA. Here, the primary product of interest has been crosslinked, hydrated polymers, or hydrogels. State-of-the-art applications of macroscopic, DNA-based hydrogels in the fields of environment, electrochemistry, biologics delivery, and regenerative therapy have been extensively reviewed. Additionally, the review encompasses the status of DNA as a clinically and commercially viable material and provides insight into future possibilities.

Design and Development of Hybrid Hydrogels for Biomedical Applications: Recent Trends in Anticancer Drug Delivery and Tissue Engineering

The applications of hydrogels in biomedical field has been since multiple decades. Discoveries in biology and chemistry render this platform endowed with much engineering potentials and growing continuously. Novel approaches in constructing these materials have led to the production of complex hybrid hydrogels systems that can incorporate both natural and synthetic polymers and other functional moieties for mediated cell response, tunable release kinetic profiles, thus they are used and research for diverse biomedical applications. Recent advancement in this field has established promising techniques for the development of biorelevant materials for construction of hybrid hydrogels with potential applications in the delivery of cancer therapeutics, drug discovery, and re-generative medicines. In this review, recent trends in advanced hybrid hydrogels systems incorporating nano/microstructures, their synthesis, and their potential applications in tissue engineering and anticancer drug delivery has been discussed. Examples of some new approaches including click reactions implementation, 3D printing, and photopatterning for the development of these materials has been briefly discussed. In addition, the application of biomolecules and motifs for desired outcomes, and tailoring of their transport and kinetic behavior for achieving desired outcomes in hybrid nanogels has also been reviewed.

Ophthalmic Drops with Nanoparticles Derived from a Natural Product for Treating Age-Related Macular Degeneration

There is a continuing, urgent need for an ophthalmic (eye) drop for the clinical therapy of age-related macular degeneration (AMD), a leading cause of blindness. Here, we report the first formulation of an eye drop that is effective via autophagy for AMD treatment. This eye drop is based on a single natural product derivative (ACD), which is an amphiphilic molecule containing a 6-aminohexanoate group (H₂N(CH₂)₅COO-). We demonstrate that this eye drop reverses the abnormal angiogenesis induced in a primate model of AMD that has the pathological characteristics close to that of human AMD. The ACD molecule was self-assembled in an aqueous environment leading to nanoparticles (NPs) about 9.0 nm in diameter. These NPs were encapsulated in calcium alginate hydrogel. The resulting eye drop effectively slowed the release of ACD and displayed extended release periods in both simulated blood (pH 7.4) and inflammatory (pH 5.2) environments. We show that the eye drop penetrated both the corneal and blood-eye barriers and reached the fundus. With low cellular toxicity, the drop targeted S1,25D₃-membrane-associated rapid response steroid-binding protein (1,25D₃-MARRS) promoting autophagy in a dose-dependent manner. In addition, the drop inhibited cell migration and tubular formation. On the other hand, when protein 1,25D₃-MARRS was knocked down, the eye drop did not exhibit such inhibition functionalities. Our study indicates that the 6-aminohexanoate group on self-assembled NPs encapsulated in hydrogel leads to the positive in vivo outcomes. The present formulation offers a promising approach for clinical treatment of human AMD.

Rational Design of DNA Framework-Based Hybrid Nanomaterials for Anticancer Drug Delivery

Engineered DNA frameworks have been extensively exploited as affinity scaffolds for drug delivery. However, few studies focus on the rational design to comprehensively improve their stability, internalization kinetics, and drug loading efficiency. Herein, DNA framework-based hybrid nanomaterials are rationally engineered by using a molecular docking tool, where the framework acts as a template to support conjugated polymers. The hybrid materials exhibit high stability in biofluids owning to the multiple interactions between DNA and cationic conjugated polymer. Through molecular docking, it is found that a specific structure of the conjugated polymer at major grooves of DNA gives rise to a unique pocket for small-molecular drug doxorubicin (DOX) yielding lower binding energy than conventional DOX binding sites. This increases the binding affinity of DOX, allowing for high drug loading content and efficiency, and preventing drug leakage under physiological condition. As a proof of concept, the hybrid nanomaterials equipped with aptamer are used to carry DOX and antisense oligonucleotide G3139, which effectively inhibits solid tumor growth and shows negligible side effects on mice. It is anticipated that this approach would find broad applications in hybrid materials design and precise medicine.

Novel Protease-Free Long-Lasting Chemiluminescence System Based on the Dox-ABEI Chimeric Magnetic DNA Hydrogel for Ultrasensitive Immunoassay

Most of chemiluminescence (CL) substrates exhibit the flash-type light emission. Therefore, the long-lasting CL system is always the crown in the field of CL-based analysis methodology. In this work, we constructed a Dox-ABEI chimeric magnetic DNA hydrogel (MDH) as a novel protease-free long-lasting CL reaction system. The functional MDH can transform flash-type ABEI/H₂O₂/CO²⁺ reaction into a glow-type CL system because of its block effect on delaying the diffusion rate of co-reactants, making the CL reaction gradually occur. More importantly, the functional MDH possessed the advantages of biocompatibility and controllability and could be well-designed to incorporate different biosensing strategies. Subsequently, we established a functional MDH-based long-lasting CL immunoassay system for ultrasensitive and highly specific detection of d-dimer and fibrin degradation products (FDPs). The designed CL immunoassay can detect d-dimer and FDP down to 53.7 and 31.6 fg/mL, respectively, with a wide line ranging from 100 fg/mL to 100 ng/mL, which was superior to the previously reported CL biosensing strategies. Moreover, benefiting from the magnetic separation of MDH and excellent CL performance, the developed immunoassaying method was successfully applied in the detection of clinical samples, which showed a close correlation with clinical reference technology. Thus, this functional MDH proved to be an excellent long-lasting CL system and a potential technical platform for clinical bioanalysis applications.

Distribution of serum specific IgE in children with allergic conjunctivitis and analysis of its concomitant allergic diseases

BACKGROUND

Allergic conjunctivitis (AC) is predominantly caused by serum specific-IgE (sIgE)-mediated type I allergy. This study aims to analyze the distribution of sIgE in children with AC, and the concomitant allergic diseases.

METHODS

The clinical data from 310 children, diagnosed with AC and admitted to our hospital from January 2017 to January 2019 were retrospectively collected. The children were divided into three groups: infant group (2 months to 1 year old, 91 cases), child group (1 to 3 years old, 112 cases), and preschool group (3 to 6 years old, 107 cases). Children in every group were analyzed for positive rates, the number of positive sIgE types, the distribution of positive inhaling and ingesting allergens and concomitant allergic diseases.

RESULTS

The sIgE positive rate of infant was significantly lower than that of the other two groups, and the number of 18.75% sIgE positive species was 1. The number of sIgE positive species in the child group and preschool group was more than 2 (78.30%, 71.15%). The positive rate of sIgE to dust mites, house dust, animal dander, eggs, beef, mutton and mango in the preschool group was significantly higher than the other groups (P<0.05). The positive rate of sIgE to milk in infant group was significantly higher than the other two groups (P<0.05). Children in the preschool group showed the highest incidence of AC, AC + allergic rhinitis, AC + allergic rhinitis + wheezing, while those in the infant group displayed the lowest incidence (P<0.05). AC + gastrointestinal allergy, AC + atopic dermatitis, AC + gastrointestinal allergy + atopic dermatitis in infant group was significantly higher than the other two groups (P<0.05). Patients in the child group displayed a significantly higher incidence of AC + infant wheezing than the other two groups (P<0.05).

CONCLUSIONS

We correlated children's age with the positive rate and gradual increase in types of AC allergens. Concomitant allergic diseases of children with AC at different ages conform to the natural course of allergic diseases. In clinic, improving the diagnostic efficiency of AC in children, and early interventional treatment will positively contribute to their prognosis, and reduce the risk of other allergic diseases.

New Developments in Medical Applications of Hybrid Hydrogels Containing Natural Polymers

New trends in biomedical applications of the hybrid polymeric hydrogels, obtained by combining natural polymers with synthetic ones, have been reviewed. Homopolysaccharides, heteropolysaccharides, as well as polypeptides, proteins and nucleic acids, are presented from the point of view of their ability to form hydrogels with synthetic polymers, the preparation procedures for polymeric organic hybrid hydrogels, general physico-chemical properties and main biomedical applications (i.e., tissue engineering, wound dressing, drug delivery, etc.).

Tailoring DNA Self-assembly to Build Hydrogels

DNA hydrogels are crosslinked polymeric networks in which DNA is used as the backbone or the crosslinker. These hydrogels are novel biofunctional materials that possess the biological character of DNA and the framed structure of hydrogels. Compared with other kinds of hydrogels, DNA hydrogels exhibit not only high mechanical strength and controllable morphologies but also good recognition ability, designable responsiveness, and programmability. The DNA used in this type of hydrogel acts as a building block for self-assembly or as a responsive element due to its sequence recognition ability and switchable structural transitions, respectively. In this review, we describe recent developments in the field of DNA hydrogels and discuss the role played by DNA in these hydrogels. Various synthetic strategies for and a range of applications of DNA hydrogels are detailed.