Engineered Hydrogels in Cancer Therapy and Diagnosis

Current advance of nanotechnology in diagnosis and treatment for malignant tumors

Cancer remains a significant risk to human health. Nanomedicine is a new multidisciplinary field that is garnering a lot of interest and investigation. Nanomedicine shows great potential for cancer diagnosis and treatment. Specifically engineered nanoparticles can be employed as contrast agents in cancer diagnostics to enable high sensitivity and high-resolution tumor detection by imaging examinations. Novel approaches for tumor labeling and detection are also made possible by the use of nanoprobes and nanobiosensors. The achievement of targeted medication delivery in cancer therapy can be accomplished through the rational design and manufacture of nanodrug carriers. Nanoparticles have the capability to effectively transport medications or gene fragments to tumor tissues via passive or active targeting processes, thus enhancing treatment outcomes while minimizing harm to healthy tissues. Simultaneously, nanoparticles can be employed in the context of radiation sensitization and photothermal therapy to enhance the therapeutic efficacy of malignant tumors. This review presents a literature overview and summary of how nanotechnology is used in the diagnosis and treatment of malignant tumors. According to oncological diseases originating from different systems of the body and combining the pathophysiological features of cancers at different sites, we review the most recent developments in nanotechnology applications. Finally, we briefly discuss the prospects and challenges of nanotechnology in cancer.

Emerging 2D Nanomaterials-Integrated Hydrogels: Advancements in Designing Theragenerative Materials for Bone Regeneration and Disease Therapy

This review highlights recent advancements in the synthesis, processing, properties, and applications of 2D-material integrated hydrogels, with a focus on their performance in bone-related applications. Various synthesis methods and types of 2D nanomaterials, including graphene, graphene oxide, transition metal dichalcogenides, black phosphorus, and MXene are discussed, along with strategies for their incorporation into hydrogel matrices. These composite hydrogels exhibit tunable mechanical properties, high surface area, strong near-infrared (NIR) photon absorption and controlled release capabilities, making them suitable for a range of regeneration and therapeutic applications. In cancer therapy, 2D-material-based hydrogels show promise for photothermal and photodynamic therapies, and drug delivery (chemotherapy). The photothermal properties of these materials enable selective tumor ablation upon NIR irradiation, while their high drug-loading capacity facilitates targeted and controlled release of chemotherapeutic agents. Additionally, 2D-materials -infused hydrogels exhibit potent antibacterial activity, making them effective against multidrug-resistant infections and disruption of biofilm generated on implant surface. Moreover, their synergistic therapy approach combines multiple treatment modalities such as photothermal, chemo, and immunotherapy to enhance therapeutic outcomes. In bio-imaging, these materials serve as versatile contrast agents and imaging probes, enabling their real-time monitoring during tumor imaging. Furthermore, in bone regeneration, most 2D-materials incorporated hydrogels promote osteogenesis and tissue regeneration, offering potential solutions for bone defects repair. Overall, the integration of 2D materials into hydrogels presents a promising platform for developing multifunctional theragenerative biomaterials.

Programmable Release of Chemotherapeutics from Ferrocene-Based Injectable Hydrogels Slows Melanoma Growth

Hydrogel-based injectable drug delivery systems provide temporally and spatially controlled drug release with reduced adverse effects on healthy tissues. Therefore, they represent a promising therapeutic option for unresectable solid tumor entities. In this study, a peptide-starPEG/hyaluronic acid-based physical hydrogel is modified with ferrocene to provide a programmable drug release orchestrated by matrix-drug interaction and local reactive oxygen species (ROS). The injectable ROS-responsive hydrogel (hiROSponse) exhibits adequate biocompatibility and biodegradability, which are important for clinical applications. HiROSponse is loaded with the two cytostatic drugs (hiROSponsedox/ptx) doxorubicin (dox) and paclitaxel (ptx). Dox is a hydrophilic compound and its release is mainly controlled by Fickian diffusion, while the hydrophobic interactions between ptx and ferrocene can control its release and thus be regulated by the oxidation of ferrocene to the more hydrophilic state of ferrocenium. In a syngeneic malignant melanoma-bearing mouse model, hiROSponsedox/ptx slows tumor growth without causing adverse side effects and doubles the relative survival probability. Programmable release is further demonstrated in a tumor model with a low physiological ROS level, where dox release, low dose local irradiation, and the resulting ROS-triggered ptx release lead to tumor growth inhibition and increased survival.

Recent Advancements in Biomaterials for Chimeric Antigen Receptor T Cell Immunotherapy

Cellular immunotherapy is an innovative cancer treatment method that utilizes the patient's own immune system to combat tumor cells effectively. Currently, the mainstream therapeutic approaches include chimeric antigen receptor T cell (CAR-T) therapy, T cell receptor gene-modified T cell therapy and chimeric antigen receptor natural killer-cell therapy with CAR-T therapy mostly advanced. Nonetheless, the conventional manufacturing process of this therapy has shortcomings in each step that call for improvement. Marked efforts have been invested for its enhancement while notable progresses achieved in the realm of biomaterials application. With CAR-T therapy as a prime example, the aim of this review is to comprehensively discuss the various biomaterials used in cell immunotherapy, their roles in regulating immune cells, and their potential for breakthroughs in cancer treatment from gene transduction to efficacy enhancement. This article additionally addressed widely adopted animal models for efficacy evaluating.

Alginate-Chitosan Biodegradable and Biocompatible Based Hydrogel for Breast Cancer Immunotherapy and Diagnosis: A Comprehensive Review

Breast cancer is the most common type of cancer and the second leading cause of cancer-related mortality in females. There are many side effects due to chemotherapy and traditional surgery, like fatigue, loss of appetite, skin irritation, and drug resistance to cancer cells. Immunotherapy has become a hopeful approach toward cancer treatment, generating long-lasting immune responses in malignant tumor patients. Recently, hydrogel has received more attention toward cancer therapy due to its specific characteristics, such as decreased toxicity, fewer side effects, and better biocompatibility drug delivery to the particular tumor location. Researchers globally reported various investigations on hydrogel research for tumor diagnosis. The hydrogel-based multilayer platform with controlled nanostructure has received more attention for its antitumor effect. Chitosan and alginate play a leading role in the formation of the cross-link in a hydrogel. Also, they help in the stability of the hydrogel. This review discusses the properties, preparation, biocompatibility, and bioavailability of various research and clinical approaches of the multipolymer hydrogel made of alginate and chitosan for breast cancer treatment. With a focus on cases of breast cancer and the recovery rate, there is a need to find out the role of hydrogel in drug delivery for breast cancer treatment.

Hydrogel: a new material for intravesical drug delivery after bladder cancer surgery

The standard treatment for non-muscle invasive bladder cancer (NMIBC) is transurethral resection of bladder tumor (TURBT). However, this procedure may miss small lesions or incompletely remove them, resulting in cancer recurrence or progression. As a result, intravesical instillation of chemotherapy or immunotherapy drugs is often used as an adjunctive treatment after TURBT to prevent cancer recurrence. In the traditional method, drugs are instilled into the patient's bladder through a urinary catheter under sterile conditions. However, this treatment exposes the bladder mucosa to the drug directly, leading to potential side effects like chemical cystitis. Furthermore, this treatment has several limitations, including a short drug retention period, susceptibility to urine dilution, low drug permeability, lack of targeted effect, and limited long-term clinical efficacy. Hydrogel, a polymer material with a high-water content, possesses solid elasticity and liquid fluidity, making it compatible with tissues and environmentally friendly. It exhibits great potential in various applications. One emerging use of hydrogels is in intravesical instillation. By employing hydrogels, drug dilution is minimized, and drug absorption, retention, and persistence in the bladder are enhanced due to the mucus-adhesive and flotation properties of hydrogel materials. Furthermore, hydrogels can improve drug permeability and offer targeting capabilities. This article critically examines the current applications and future prospects of hydrogels in the treatment of bladder cancer.

Current status of development and biomedical applications of peptide-based antimicrobial hydrogels

Microbial contamination poses a serious threat to human life and health. Through the intersection of material science and modern medicine, advanced bionic hydrogels have shown great potential for biomedical applications due to their unique bioactivity and ability to mimic the extracellular matrix environment. In particular, as a promising antimicrobial material, the synthesis and practical biomedical applications of peptide-based antimicrobial hydrogels have drawn increasing research interest. The synergistic effect of peptides and hydrogels facilitate the controlled release of antimicrobial agents and mitigation of their biotoxicity while achieving antimicrobial effects and protecting the active agents from degradation. This review reports on the progress and trends of researches in the last five years and provides a brief outlook, aiming to provide theoretical background on peptide-based antimicrobial hydrogels and make suggestions for future related work.

3D sponge loaded with cisplatin-CS-calcium alginate MPs utilized as a void-filling prosthesis for the efficient postoperative prevention of tumor recurrence and metastasis

Intraoperative bleeding is a pivotal factor in the initiation of early recurrence and tumor metastasis following breast cancer excision. Distinct advantages are conferred upon postoperative breast cancer treatment through the utilization of locally administered implant therapies. This study devised a novel 3D sponge implant containing cisplatin-loaded chitosan-calcium alginate MPs capable of exerting combined chemotherapy and hemostasis effects. This innovative local drug-delivery implant absorbed blood and residual tumor cells post-tumor resection. Furthermore, the cisplatin-loaded chitosan-calcium alginate MPs sustainably targeted and eliminated cancer cells, thereby diminishing the risk of local recurrence and distant metastasis. This hydrogel material can also contribute to breast reconstruction, indicating the potential application of the 3D sponge in drug delivery for breast cancer treatment.

Injectable liposome-containing click hydrogel microparticles for release of macromolecular cargos

Hydrogel microparticles ranging from 0.1-100 μm, referred to as microgels, are attractive for biological applications afforded by their injectability and modularity, which allows facile delivery of mixed populations for tailored combinations of therapeutics. Significant efforts have been made to broaden methods for microgel production including via the materials and chemistries by which they are made. Via droplet-based-microfluidics we have established a method for producing click poly-(ethylene)-glycol (PEG)-based microgels with or without chemically crosslinked liposomes (lipo-microgels) through the Michael-type addition reaction between thiol and either vinyl-sulfone or maleimide groups. Unifom spherical microgels and lipo-microgels were generated with sizes of 74 ± 16 μm and 82 ± 25 μm, respectively, suggesting injectability that was further supported by rheological analyses. Super-resolution confocal microscopy was used to further verify the presence of liposomes within the lipo-microgels and determine their distribution. Atomic force microscopy (AFM) was conducted to compare the mechanical properties and network architecture of bulk hydrogels, microgels, and lipo-microgels. Further, encapsulation and release of model cargo (FITC-Dextran 5 kDa) and protein (equine myoglobin) showed sustained release for up to 3 weeks and retention of protein composition and secondary structure, indicating their ability to both protect and release cargos of interest.

Engineered cyclodextrin-based supramolecular hydrogels for biomedical applications

Cyclodextrin (CD)-based supramolecular hydrogels are polymer network systems with the ability to rapidly form reversible three-dimensional porous structures through multiple cross-linking methods, offering potential applications in drug delivery. Although CD-based supramolecular hydrogels have been increasingly used in a wide range of applications in recent years, a comprehensive description of their structure, mechanical property modulation, drug loading, delivery, and applications in biomedical fields from a cross-linking perspective is lacking. To provide a comprehensive overview of CD-based supramolecular hydrogels, this review systematically describes their design, regulation of mechanical properties, modes of drug loading and release, and their roles in various biomedical fields, particularly oncology, wound dressing, bone repair, and myocardial tissue engineering. Additionally, this review provides a rational discussion on the current challenges and prospects of CD-based supramolecular hydrogels, which can provide ideas for the rapid development of CD-based hydrogels and foster their translation from the laboratory to clinical medicine.

Application of pyroptosis in tumor research (Review)

As a potent clinical strategy, cancer therapy has sparked an academic boom over the past few years. Immune checkpoint inhibitors (ICIs) have been demonstrated to be highly successful. These achievements have progressed cancer treatment and have made an indelible mark on cancer. However, the inherent complexity of cancer means that only part of the population can benefit from this treatment. Pyroptosis is a new suicidal cellular mechanism that induces inflammation by releasing immunogenic cellular components. Inflammatory signaling cascades mediated by pyroptosis commonly inspire numerous cell lysis in immune diseases. Contrariwise, this consequence may be a promising target in cancer research. Therefore, the present study briefly described programmed cell death processes and their potential roles in cancer. Because of the rapid development of bioengineering in cancer, the present study also examined the associated scaffolding available for cancer, highlighting advances in tumor engineering approaches. Ultimately, an improved understanding of pyroptosis and tumor scaffolding might shed light on a combination that can be manipulated for therapeutic purposes.

Recent Advances on Cell Culture Platforms for In Vitro Drug Screening and Cell Therapies: From Conventional to Microfluidic Strategies

The clinical translations of drugs and nanomedicines depend on coherent pharmaceutical research based on biologically accurate screening approaches. Since establishing the 2D in vitro cell culture method, the scientific community has improved cell-based drug screening assays and models. Those advances result in more informative biochemical assays and the development of 3D multicellular models to describe the biological complexity better and enhance the simulation of the in vivo microenvironment. Despite the overall dominance of conventional 2D and 3D cell macroscopic culture methods, they present physicochemical and operational challenges that impair the scale-up of drug screening by not allowing a high parallelization, multidrug combination, and high-throughput screening. Their combination and complementarity with microfluidic platforms enable the development of microfluidics-based cell culture platforms with unequivocal advantages in drug screening and cell therapies. Thus, this review presents an updated and consolidated view of cell culture miniaturization's physical, chemical, and operational considerations in the pharmaceutical research scenario. It clarifies advances in the field using gradient-based microfluidics, droplet-based microfluidics, printed-based microfluidics, digital-based microfluidics, SlipChip, and paper-based microfluidics. Finally, it presents a comparative analysis of the performance of cell-based methods in life research and development to achieve increased precision in the drug screening process.

Poly Ethylene Glycol (PEG)-Based Hydrogels for Drug Delivery in Cancer Therapy: A Comprehensive Review

Hydrogel-based drug delivery systems (DDSs) can leverage therapeutically beneficial outcomes in cancer therapy. In this domain, polyethylene glycol (PEG) has become increasingly popular as a biomedical polymer and has found clinical use. Owing to their excellent biocompatibility, facile modifiability, and high drug encapsulation rate, PEG hydrogels have shown great promise as drug delivery platforms. Here, the progress in emerging novel designs of PEG-hydrogels as DDSs for anti-cancer therapy is reviewed and discussed, focusing on underpinning multiscale release mechanisms categorized under stimuli-responsive and non-responsive drug release. The responsive drug delivery approaches are discussed, and the underpinning release mechanisms are elucidated, covering the systems functioning based on either exogenous stimuli-response, such as photo- and magnetic-sensitive PEG hydrogels, or endogenous stimuli-response, such as enzyme-, pH-, reduction-, and temperature-sensitive PEG hydrogels. Special attention is paid to the commercial potential of PEG-based hydrogels in cancer therapy, highlighting the limitations that need to be addressed in future research for their clinical translation.

Localized Drug Delivery Systems: An Update on Treatment Options for Head and Neck Squamous Cell Carcinomas

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers in the world, with surgery, radiotherapy, chemotherapy, and immunotherapy being the primary treatment modalities. The treatment for HNSCC has evolved over time, due to which the prognosis has improved drastically. Despite the varied treatment options, major challenges persist. HNSCC chemotherapeutic and immunotherapeutic drugs are usually administered systemically, which could affect the patient's quality of life due to the associated side effects. Moreover, the systemic administration of salivary stimulating agents for the treatment of radiation-induced xerostomia is associated with toxicities. Localized drug delivery systems (LDDS) are gaining importance, as they have the potential to provide non-invasive, patient-friendly alternatives to cancer therapy with reduced dose-limiting toxicities. LDDSs involve directly delivering a drug to the tissue or organ affected by the disease. Some of the common localized routes of administration include the transdermal and transmucosal drug delivery system (DDSs). This review will attempt to explore the different treatment options using LDDSs for the treatment of HNSCC and radiotherapy-induced damage and their potential to provide a better experience for patients, as well as the obstacles that need to be addressed to render them successful.

Nanoparticles as drug delivery systems in the treatment of oral squamous cell carcinoma: current status and recent progression

Oral squamous cell carcinoma (OSCC) is a common human malignancy with an estimated incidence of around 377,713 new cases worldwide in 2020. Despite the advance in clinical management, some of OSCC patients still miss the opportunity of completable resection of tumor, and have to accept medical therapies, e.g., chemotherapy, radiotherapy, or immunotherapy when the disease develops into the advanced stage. However, these therapies have been reported to be far from ideal due to the low efficiency of conventional delivery approaches. To obtain a better therapeutic effect, considerable attempts have been made toward to develop an effective drug delivery system (DDS). Nanoparticles (NPs) including inorganic NPs, polymer NPs, lipid NP, extracellular vesicles and cell membrane-based NPs have been evaluated as the better DDS candidates that can specifically accumulate in the tumor microenvironment along with a large amount of blood vessels. Emerging evidence suggested that NPs formulated with anticancer drugs including chemotherapeutic drugs, radiotherapy and immunotarget antibodies could remarkably improve the release and increase concentration of these drugs at the tumor site and show a better therapeutic efficacy, suggesting that NPs might serve as promising DDSs in the treatment of OSCC. Therefore, we have conducted this review to summarize recent progression and current status of diverse NPs as DDSs in this research field.

Gel Formulations for Topical Treatment of Skin Cancer: A Review

Skin cancer, with all its variations, is the most common type of cancer worldwide. Chemotherapy by topical application is an attractive strategy because of the ease of application and non-invasiveness. At the same time, the delivery of antineoplastic agents through the skin is difficult because of their challenging physicochemical properties (solubility, ionization, molecular weight, melting point) and the barrier function of the stratum corneum. Various approaches have been applied in order to improve drug penetration, retention, and efficacy. This systematic review aims at identifying the most commonly used techniques for topical drug delivery by means of gel-based topical formulations in skin cancer treatment. The excipients used, the preparation approaches, and the methods characterizing gels are discussed in brief. The safety aspects are also highlighted. The combinatorial formulation of nanocarrier-loaded gels is also reviewed from the perspective of improving drug delivery characteristics. Some limitations and drawbacks in the identified strategies are also outlined and considered within the future scope of topical chemotherapy.

Hydrogel-Based Flexible Electronics

Flexible electronics is an emerging field of research involving multiple disciplines, which include but not limited to physics, chemistry, materials science, electronic engineering, and biology. However, the broad applications of flexible electronics are still restricted due to several limitations, including high Young's modulus, poor biocompatibility, and poor responsiveness. Innovative materials aiming for overcoming these drawbacks and boost its practical application is highly desirable. Hydrogel is a class of 3D crosslinked hydrated polymer networks, and its exceptional material properties render it as a promising candidate for the next generation of flexible electronics. Here, the latest methods of synthesizing advanced functional hydrogels and the state-of-art applications of hydrogel-based flexible electronics in various fields are reviewed. More importantly, the correlation between properties of the hydrogel and device performance is discussed here, to have better understanding of the development of flexible electronics by using environmentally responsive hydrogels. Last, perspectives on the current challenges and future directions in the development of hydrogel-based multifunctional flexible electronics are provided.

Development of alginate-based hydrogels: Crosslinking strategies and biomedical applications

Natural polysaccharide-based hydrogels have drawn much concern in the biomedical fields. Among them, alginate, a natural polyanionic polysaccharide, has become one of the research hotspots, because of its abundant source, biodegradability, biocompatibility, solubility, modification flexibility, and other characteristics or physiological functions. Recently, through adopting various physical or chemical crosslinking strategies, selecting suitable crosslinking or modification reagents, precisely controlling the reaction conditions, or introducing organic or inorganic functional materials, a variety of alginate-based hydrogels with excellent performance have been continuously developed, considerably expanding the breadth and depth of their applications. Here, various crosslinking strategies in the preparation of alginate-based hydrogels are comprehensively introduced. The representative application progress of alginate-based hydrogels in drug carrier, wound dressing and tissue engineering is also summarized. Meanwhile, the application prospects, challenges and development trends of alginate-based hydrogels are discussed. It is expected to provide guidance and reference for the further development of alginate-based hydrogels.

Modeling Gas Plasma-Tissue Interactions in 3D Collagen-Based Hydrogel Cancer Cell Cultures

Gas plasma jet technology was recently identified as a potential adjuvant in the fight against cancer. Here, the partial ionization of gas yields the local formation of an exceptional variety of highly reactive oxygen (ROS) and nitrogen (RNS) species, which are considered the main actors of plasma-induced antitumor effects. Yet, fundamental knowledge in preclinical plasma research relies on the predominant use of two-dimensional cell culture systems, despite causing significant shifts in redox chemistries that largely limit translational relevance. So far, the intricacy of studying complex plasma–tissue interactions causes substantial knowledge gaps concerning the key mechanisms and therapeutical limitations of plasma treatment in a living organism. Identifying physiologically relevant yet simplified tissue models is vital to address such questions. In our study, a side-by-side comparison of conventional and pre-established hydrogel models emphasized this discrepancy, revealing a marked difference in plasma-induced toxicity related to species distribution dynamics. Chemically embedded, fluorescent reporters were further used to characterize reactive species’ fingerprints in hydrogels compared to liquids. In addition, a thirteen cell-line screening outlined the widespread applicability of the approach while indicating the need to optimize growth conditions dependent on the cell line investigated. Overall, our study presents important implications for the implementation of clinically relevant tissue culture models in preclinical plasma medicine in the future.

Recent advances in hydrogels for preventing tumor recurrence

Malignant tumors remain a high-risk disease with high mortality all over the world. Among all the cancer treatments, surgery is the primary approach in the clinical treatment of tumors. However, tumor invasion and metastasis pose challenges for complete tumor resection, accompanied by high recurrence rates and reduced quality of life. Hence, there is an urgent need to explore effective adjuvant therapies to prevent postoperative tumor recurrence and relieve the pain of the patients. Nowadays, the booming local drug delivery systems which can be applied as postoperative adjuvant therapies have aroused people's attention, along with the rapid development in the pharmaceutical and biological materials fields. Hydrogels are a kind of unique carrier with prominent biocompatibility among a variety of biomaterials. Due to their high similarity to human tissues, hydrogels which load drugs/growth factors can prevent rejection reactions and promote wound healing. In addition, hydrogels are able to cover the postoperative site and maintain sustained drug release for the prevention of tumor recurrence. In this review, we survey controlled drug delivery hydrogels such as implantable, injectable and sprayable formulations and summarize the properties required for hydrogels used as postoperative adjuvant therapies. The opportunities and challenges in the design and clinical application of these hydrogels are also elaborated.

Cell migration induces apoptosis in osteosarcoma cell via inhibition of Wnt-β-catenin signaling pathway

The current design scheme on anti-cancer materials is mainly through tuning the mechanical properties of the materials to induce apoptosis in cancer cells, with the involvement of Rho/ROCK signaling pathway. We hypothesize that tuning the motility is another potential important approach to modifying the tumor microenvironment and inducing tumor apoptosis. To this aim, we have prepared RGD-modified substrates to regulate cell motility through modification of RGD with different concentrations, and systematically examined the effect of motility on the apoptosis of tumor cells, and the potential involvement of Wnt signaling pathway. Our studies indicated that RGD modification could be readily used to tune the motility of cancer cells. High RGD concentration significantly suppressed the migration of cancer cells, leading to significantly increased apoptosis rate, about three times of that of the unmodified samples. Western-blot analysis also showed that cell with low motility expressed more caspase-3 and PARP proteins. Further RNA sequence study strongly suggested that low motility inhibited the canonical Wnt signaling pathway, which in turn led to the activation of the mitochondria-associated caspase signaling pathway, and ultimately to the apoptosis of osteosarcoma cells. Activation of the Wnt-β-catenin pathway through HLY78 significantly suppressed the apoptosis of MG-63 cells, further suggesting the critical role of Wnt pathway in motility-regulated-apoptosis of tumor cells. Our findings shed insights to understand the underlying mechanisms that induced the tumor cell apoptosis, and might provide new strategy for designing the novel anti-tumor materials.

Pluronic® triblock copolymer-based nanoformulations for cancer therapy: A 10-year overview

This paper provides a review of the literature on the use of Pluronic® triblock copolymers for drug encapsulation over the last 10 years. A special focus is given to the progress of drug delivery systems (e.g., micelles, liposomes, micro/nanoemulsions, hydrogels and nanogels, and polymersomes and niosomes); the beneficial aspects of Pluronic® triblock copolymers as biological response modifiers and as pharmaceutical additives, adjuvants, and stabilizers, are also discussed. The advantages and limitations encountered in developing site-specific targeting approaches based on Pluronic-based nanostructures in cancer treatment are highlighted, in addition to innovative examples for improving tumor cytotoxicity while reducing side effects.

Cytotoxicity towards Breast Cancer Cells of Pluronic F-127/Hyaluronic Acid Hydrogel Containing Nitric Oxide Donor and Silica Nanoparticles Loaded with Cisplatin

The incorporation of both nitric oxide (NO) donor (S-nitrosoglutathione, GSNO) and silica nanoparticles loaded with cisplatin (SiO₂@CisPt NPs) into a polymeric matrix represents a suitable approach to creating a drug-delivery system with sustained and localized drug release against tumor cells. Herein, we report the synthesis, characterization, and cytotoxicity evaluation of Pluronic F-127/hyaluronic acid hydrogel containing GSNO and SiO₂@CisPt NPs against breast cancer cells. SiO₂@CisPt NPs were successfully synthesized, revealing a spherical morphology with an average size of 158 ± 20 nm. Both GSNO and SiO₂@CisPt NPs were incorporated into the thermoresponsive Pluronic/hyaluronic hydrogel for sustained and localized release of both NO and cisplatin. The kinetics of NO release from a hydrogel matrix revealed spontaneous and sustained release of NO at the millimolar range for 24 h. The MTT assay showed concentration-dependent cytotoxicity of the hydrogel. The combination of GSNO and SiO₂@CisPt incorporated into a polymeric matrix decreased the cell viability 20% more than the hydrogel containing only GSNO or SiO₂@CisPt. At 200 µg/mL, this combination led to a critical cell viability of 30%, indicating a synergistic effect between GSNO and SiO₂@CisPt NPs in the hydrogel matrix, and, therefore, highlighting the potential application of this drug-delivery system in the field of biomedicine.

Cellulose-based hydrogels towards an antibacterial wound dressing

Hydrogels are promising candidates for wound healing bandages because they can mimic the native skin microenvironment. Additionally, there is increasing growth in the use of naturally derived materials and plant-based biomaterials to produce healthcare products with healing purposes because of their biocompatibility and biodegradation properties. In this study, cellulose extracted from biodiverse sources in Ecuador was used as the raw material for the fabrication of hydrogels with enhanced antifouling properties. Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to characterize the cellulose and hydrogels. In vitro and ex vivo tests were performed to evaluate the antimicrobial activity of hydrogels against Gram-negative bacteria as a model. Finally, the hydrogel synthesized with cellulose extracted from pitahaya showed improved antibacterial activity when applied over pigskin as a proof of concept for wound dressing. Therefore, the present results suggest that cellulose-based hydrogels are good candidates for application as wound dressings.

Hopping Behavior Mediates the Anomalous Confined Diffusion of Nanoparticles in Porous Hydrogels

Diffusion is an essential means of mass transport in porous materials such as hydrogels, which are appealing in various biomedical applications. Herein, we investigate the diffusive motion of nanoparticles (NPs) in porous hydrogels to provide a microscopic view of confined diffusion. Based on the mean square displacement from particle tracking experiments, we elucidate the anomalous diffusion dynamics of the embedded NPs and reveal the heterogeneous pore structures in hydrogels. The results demonstrate that diffusive NPs can intermittently escape from single pores through void connective pathways and exhibit non-Gaussian displacement probability distribution. We simulate this scenario using the Monte Carlo method and clarify the existence of hopping events in porous diffusion. The resultant anomalous diffusion can be fully depicted by combining the hopping mechanism and the hydrodynamic effect. Our results highlight the hopping behavior through the connective pathways and establish a hybrid model to predict NP transport in porous environments.

Three-Dimensional in Vitro Models: A Promising Tool To Scale-Up Breast Cancer Research

Common models used in breast cancer studies, including two-dimensional (2D) cultures and animal models, do not precisely model all aspects of breast tumors. These models do not well simulate the cell-cell and cell-stromal interactions required for normal tumor growth in the body and lake tumor like microenvironment. Three-dimensional (3D) cell culture models are novel approaches to studying breast cancer. They do not have the restrictions of these conventional models and are able to recapitulate the structural architecture, complexity, and specific function of breast tumors and provide similar in vivo responses to therapeutic regimens. These models can be a link between former traditional 2D culture and in vivo models and are necessary for further studies in cancer. This review attempts to summarize the most common 3D in vitro models used in breast cancer studies, including scaffold-free (spheroid and organoid), scaffold-based, and chip-based models, particularly focused on the basic and translational application of these 3D models in drug screening and the tumor microenvironment in breast cancer.

Scaffold-mediated switching of lymphoma metabolism in culture

Background

Diffuse large B cell lymphoma (DLBCL) is an aggressive subtype of non-Hodgkin lymphoma (NHL) and accounts for about a third of all NHL cases. A significant proportion (~40%) of treated DLBCL patients develop refractory or relapsed disease due to drug resistance which can be attributed to metabolomic and genetic variations amongst diverse DLBCL subtypes. An assay platform that reproduces metabolic patterns of DLBCL in vivo could serve as a useful model for DLBCL.

Methods

This report investigated metabolic functions in 2D and 3D cell cultures using parental and drug-resistant DLBCL cell lines as compared to patient biopsy tissue.

Results

A 3D culture model controlled the proliferation of parental and drug-resistant DLBCL cell lines, SUDHL-10, SUDHL-10 RR (rituximab resistant), and SUDHL-10 OR (obinutuzumab resistant), as well as retained differential sensitivity to CHOP. The results from metabolic profiling and isotope tracer studies with d-glucose-¹³C₆ indicated metabolic switching in 3D culture when compared with a 2D environment. Analysis of DLBCL patient tumor tissue revealed that the metabolic changes in 3D grown cells were shifted towards that of clinical specimens.

Conclusion

3D culture restrained DLBCL cell line growth and modulated metabolic pathways that trend towards the biological characteristics of patient tumors. Counter-intuitively, this research thereby contends that 3D matrices can be a tool to control tumor function towards a slower growing and metabolically dormant state that better reflects in vivo tumor physiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40170-022-00291-y.

Gene Regulations upon Hydrogel-Mediated Drug Delivery Systems in Skin Cancers-An Overview

The incidence of skin cancer has increased dramatically in recent years, particularly in Caucasian populations. Specifically, the metastatic melanoma is one of the most aggressive cancers and is responsible for more than 80% of skin cancer deaths around the globe. Though there are many treatment techniques, and drugs have been used to cure this belligerent skin cancer, the side effects and reduced bioavailability of drug in the targeted area makes it difficult to eradicate. In addition, cellular metabolic pathways are controlled by the skin cancer driver genes, and mutations in these genes promote tumor progression. Consequently, the MAPK (RAS-RAF-MEK-ERK pathway), WNT and PI3K signaling pathways are found to be important molecular regulators in melanoma development. Even though hydrogels have turned out to be a promising drug delivery system in skin cancer treatment, the regulations at the molecular level have not been reported. Thus, we aimed to decipher the molecular pathways of hydrogel drug delivery systems for skin cancer in this review. Special attention has been paid to the hydrogel systems that deliver drugs to regulate MAPK, PI3K-AKT-mTOR, JAK-STAT and cGAS-STING pathways. These signaling pathways can be molecular drivers of skin cancers and possible potential targets for the further research on treatment of skin cancers.

Functional Nanoparticles for Enhanced Cancer Therapy

Cancer is the leading cause of death in people worldwide. The conventional therapeutic approach is mainly based on chemotherapy, which has a series of side effects. Compared with traditional chemotherapy drugs, nanoparticle-based delivery of anti-cancer drugs possesses a few attractive features. The application of nanotechnology in an interdisciplinary manner in the biomedical field has led to functional nanoparticles achieving much progress in cancer therapy. Nanoparticles have been involved in the diagnosis and targeted and personalized treatment of cancer. For example, different nano-drug strategies, including endogenous and exogenous stimuli-responsive, surface conjugation, and macromolecular encapsulation for nano-drug systems, have successfully prevented tumor procession. The future for functional nanoparticles is bright and promising due to the fast development of nanotechnology. However, there are still some challenges and limitations that need to be considered. Based on the above contents, the present article analyzes the progress in developing functional nanoparticles in cancer therapy. Research gaps and promising strategies for the clinical application are discussed.

Encapsulation of miRNA and siRNA into Nanomaterials for Cancer Therapeutics

Globally, cancer is amongst the most deadly diseases due to the low efficiency of the conventional and obsolete chemotherapeutic methodologies and their many downsides. The poor aqueous solubility of most anticancer medications and their low biocompatibility make them ineligible candidates for the design of delivery systems. A significant drawback associated with chemotherapy is that there are no advanced solutions to multidrug resistance, which poses a major obstacle in cancer management. Since RNA interference (RNAi) can repress the expression of genes, it is viewed as a novel tool for advanced drug delivery. this is being explored as a promising drug targeting strategy for the treatment of multiple diseases, including cancer. However, there are many obstructions that hinder the clinical uses of siRNA drugs due to their low permeation into cells, off-target impacts, and possible unwanted immune responses under physiological circumstances. Thus, in this article, we review the design measures for siRNA conveyance frameworks and potential siRNA and miRNA drug delivery systems for malignant growth treatment, including the use of liposomes, dendrimers, and micelle-based nanovectors and functional polymer-drug delivery systems. This article sums up the advancements and challenges in the use of nanocarriers for siRNA delivery and remarkably centers around the most critical modification strategies for nanocarriers to build multifunctional siRNA and miRNA delivery vectors. In short, we hope this review will throw light on the dark areas of RNA interference, which will further open novel research arenas in the development of RNAi drugs for cancer.

Call the Eckols: Present and Future Potential Cancer Therapies

In recent years, an increased interest in marine macroalgae bioactive compounds has been recorded due to their benefits to human health and welfare. Several of their bioactivities have been demonstrated, such as anti-inflammatory, antioxidant, anticarcinogenic, antibacterial and antiviral behavior. However, there still lacks a clear definition regarding how these compounds exert their bioactive properties. Of all the bioactive compounds derived from marine macroalgae, attention has been focused on phenolic compounds, specifically in phlorotannins, due to their potential for biomedical applications. Phlorotannins are a diverse and wide group of phenolic compounds, with several structural variations based on the monomer phloroglucinol. Among the diverse phlorotannin structures, the eckol-family of phlorotannins demonstrates remarkable bioactivity, notably their anti-tumoral properties. However, the molecular mechanisms by which this activity is achieved remain elusive and sparse. This review focuses on the described molecular mechanisms of anti-tumoral effects by the eckol family of compounds and the future prospects of these molecules for potential application in oncology therapies.

PEIGel: A biocompatible and injectable scaffold with innate immune adjuvanticity for synergized local immunotherapy

Intratumoral immunotherapeutic hydrogel administration is emerging as an effective method for inducing a durable and robust antitumor immune response. However, scaffold hydrogels that can synergize with the loaded drugs, thus potentiating therapeutic efficacy, are limited. Here, we report a ternary hydrogel composed of polyvinyl alcohol (PVA), polyethylenimine (PEI)‒a cationic polymer with potential immunoactivation effects, and magnesium ions‒a stimulator of the adaptive immune response, which exhibits an intrinsic immunomodulation function of reversing the immunologically "cold" phenotype of a murine breast tumor to a "hot" phenotype by upregulating PD-L1 expression and promoting M1-like macrophage polarization. PEI hydrogel (PEIGel) encapsulating an immune checkpoint blockade (ICB) inhibitor‒anti-PD-L1 antibody (α-PDL1) exhibits synergistic effects resulting in elimination of primary tumors and remote metastases and prevention of tumor relapse after surgical resection. A preliminary mechanistic study revealed a probably hidden role of PEI in modulating the polyamine metabolism/catabolism of tumors to potentiate the immune adjuvant effect. These results deepen our understanding of the innate immune activation function of PEI and pave the way for harnessing PEI as an immune adjuvant for ICB therapy.

Application and Prospects of Hydrogel Additive Manufacturing

Hydrogel has become a commonly used material for 3D and 4D printing due to its favorable biocompatibility and low cost. Additive manufacturing, also known as 3D printing, was originally referred to as rapid prototyping manufacturing. Variable-feature rapid prototyping technology, also known as 4D printing, is a combination of materials, mathematics, and additives. This study constitutes a literature review to address hydrogel-based additive manufacturing technologies, introducing the characteristics of commonly used 3D printing hydrogel methods, such as direct ink writing, fused deposition modeling, and stereolithography. With this review, we also investigated the stimulus types, as well as the advantages and disadvantages of various stimulus-responsive hydrogels in smart hydrogels; non-responsive hydrogels; and various applications of additive manufacturing hydrogels, such as neural catheter preparation and drug delivery. The opportunities, challenges, and future prospects of hydrogel additive manufacturing technologies are discussed.

Hydrogels for localized chemotherapy of liver cancer: a possible strategy for improved and safe liver cancer treatment

The systemic drug has historically been preferred for the treatment of the majority of pathological conditions, particularly liver cancer. Indeed, this mode of treatment is associated with adverse reactions, toxicity, off-target accumulation, and rapid hepatic and renal clearance. Numerous efforts have been made to design systemic therapeutic carriers to improve retention while decreasing side effects and clearance. Following systemic medication, local administration of therapeutic agents allows for higher 'effective' doses with fewer side effects, kidney accumulation, and clearance. Hydrogels are highly biocompatible and can be used for both imaging and therapy. Hydrogel-based drug delivery approach has fewer side effects than traditional chemotherapy and can deliver drugs to tumors for a longer time. The chemical and physical flexibility of hydrogels can be used to achieve disease-induced in situ accumulation as well as subsequent drug release and hydrogel-programmed degradation. Moreover, they can act as a biocompatible depot for localized chemotherapy when stimuli-responsive carriers are administrated. Herein, we summarize the design strategies of various hydrogels used for localized chemotherapy of liver cancer and their delivery routes, as well as recent research on smart hydrogels.

Nanocomposite hydrogels for biomedical applications

Nanomaterials' unique structures at the nanometer level determine their incredible functions, and based on this, they can be widely used in the field of nanomedicine. However, nanomaterials do possess disadvantages that cannot be ignored, such as burst release, rapid elimination, and poor bioadhesion. Hydrogels are scaffolds with three‐dimensional structures, and they exhibit good biocompatibility and drug release capacity. Hydrogels are also associated with disadvantages for biomedical applications such as poor anti‐tumor capability, weak bioimaging capability, limited responsiveness, and so on. Incorporating nanomaterials into the 3D hydrogel network through physical or chemical covalent action may be an effective method to avoid their disadvantages. In nanocomposite hydrogel systems, multifunctional nanomaterials often work as the function core, giving the hydrogels a variety of properties (such as photo‐thermal conversion, magnetothermal conversion, conductivity, targeting tumor, etc.). While, hydrogels can effectively improve the retention effect of nanomaterials and make the nanoparticles have good plasticity to adapt to various biomedical applications (such as various biosensors). Nanocomposite hydrogel systems have broad application prospects in biomedicine. In this review, we comprehensively summarize and discuss the most recent advances of nanomaterials composite hydrogels in biomedicine, including drug and cell delivery, cancer treatment, tissue regeneration, biosensing, and bioimaging, and we also briefly discussed the current situation of their commoditization in biomedicine.

Hydrogels and Hydrogel Nanocomposites: Enhancing Healthcare through Human and Environmental Treatment

Humans are constantly exposed to exogenous chemicals throughout their life, which can lead to a multitude of negative health impacts. Advanced materials can play a key role in preventing or mitigating these impacts through a wide variety of applications. The tunable properties of hydrogels and hydrogel nanocomposites (e.g., swelling behavior, biocompatibility, stimuli responsiveness, functionality, etc.) have deemed them ideal platforms for removal of environmental contaminants, detoxification, and reduction of body burden from exogenous chemical exposures for prevention of disease initiation, and advanced treatment of chronic diseases, including cancer, diabetes, and cardiovascular disease. In this review, three main junctures where the use of hydrogel and hydrogel nanocomposite materials can intervene to positively impact human health are highlighted: 1) preventing exposures to environmental contaminants, 2) prophylactic treatments to prevent chronic disease initiation, and 3) treating chronic diseases after they have developed.

Versatility of Hydrogels: From Synthetic Strategies, Classification, and Properties to Biomedical Applications

Hydrogels are three-dimensional, cross-linked, and supramolecular networks that can absorb significant volumes of water. Hydrogels are one of the most promising biomaterials in the biological and biomedical fields, thanks to their hydrophilic properties, biocompatibility, and wide therapeutic potential. Owing to their nontoxic nature and safe use, they are widely accepted for various biomedical applications such as wound dressing, controlled drug delivery, bone regeneration, tissue engineering, biosensors, and artificial contact lenses. Herein, this review comprises different synthetic strategies for hydrogels and their chemical/physical characteristics, and various analytical, optical, and spectroscopic tools for their characterization are discussed. A range of synthetic approaches is also covered for the synthesis and design of hydrogels. It will also cover biomedical applications such as bone regeneration, tissue engineering, and drug delivery. This review addressed the fundamental, general, and applied features of hydrogels in order to facilitate undergraduates, graduates, biomedical students, and researchers in a variety of domains.

Targeted drug delivery in cervical cancer: Current perspectives

Cervical cancer is preventable yet one of the most prevalent cancers among women around the globe. Though regular screening has resulted in the decline in incidence, the disease claims a high number of lives every year, especially in the developing countries. Owing to rather aggressive and non-specific nature of the conventional chemotherapeutics, there is a growing need for newer treatment modalities. The advent of nanotechnology has assisted in this through the use of nanocarriers for targeted drug delivery. A number of nanocarriers are continuously being developed and studied for their application in drug delivery. The present review summarises the different drug delivery approaches and nanocarriers that can be useful, their advantages and limitation.

Hybrid in situ- forming injectable hydrogels for local cancer therapy

Injectable in situ forming hydrogels are amongst the efficient local drug delivery systems for cancer therapy. Providing a 3D hydrogel network within the target tissue capable of sustained release of the chemotherapeutics made them attractive candidates for increasing the therapeutic index. Remarkable swelling properties, mechanical strength, biocompatibility, wide composition variety and tunable polymeric moieties have led to preparation of injectable hydrogels which also could be used as cavity adaptive chemotherapeutic-loaded implants to prevent post -surgical cancer recurrence. Implementation of various polymers, nanoparticles, peptide and proteins and different crosslinking chemistry facilitated the fabrication of hybrid hydrogels with favorable characteristics such as stimuli sensitive platforms or multifunctional systems. In the current review, we focused on design and fabrication strategies of injectable in situ forming hydrogels and summarized recent hybrid hydrogels used for local cancer therapy.

Photothermal scaffolds/surfaces for regulation of cell behaviors

Regulation of cell behaviors and even cell fates is of great significance in diverse biomedical applications such as cancer treatment, cell-based therapy, and tissue engineering. During the past decades, diverse methods have been developed to regulate cell behaviors such as applying external stimuli, delivering exogenous molecules into cell interior and changing the physicochemical properties of the substrates where cells adhere. Photothermal scaffolds/surfaces refer to a kind of materials embedded or coated with photothermal agents that can absorb light with proper wavelength (usually in near infrared region) and convert light energy to heat; the generated heat shows great potential for regulation of cell behaviors in different ways. In the current review, we summarize the recent research progress, especially over the past decade, of using photothermal scaffolds/surfaces to regulate cell behaviors, which could be further categorized into three types: (i) killing the tumor cells via hyperthermia or thermal ablation, (ii) engineering cells by intracellular delivery of exogenous molecules via photothermal poration of cell membranes, and (iii) releasing a single cell or an intact cell sheet via modulation of surface physicochemical properties in response to heat. In the end, challenges and perspectives in these areas are commented.

Bioinspired and Biomimetic Delivery Platforms for Cancer Vaccines

Cancer vaccines aim at eliciting tumor-specific responses for the immune system to identify and eradicate malignant tumor cells while sparing the normal tissues. Furthermore, cancer vaccines can potentially induce long-term immunological memory for antitumor responses, preventing metastasis and cancer recurrence, thus presenting an attractive treatment option in cancer immunotherapy. However, clinical efficacy of cancer vaccines has remained low due to longstanding challenges, such as poor immunogenicity, immunosuppressive tumor microenvironment, tumor heterogeneity, inappropriate immune tolerance, and systemic toxicity. Recently, bioinspired materials and biomimetic technologies have emerged to play a part in reshaping the field of cancer nanomedicine. By mimicking desirable chemical and biological properties in nature, bioinspired engineering of cancer vaccine delivery platforms can effectively transport therapeutic cargos to tumor sites, amplify antigen and adjuvant bioactivities, and enable spatiotemporal control and on-demand immunoactivation. As such, integration of biomimetic designs into delivery platforms for cancer vaccines can enhance efficacy while retaining good safety profiles, which contributes to expediting the clinical translation of cancer vaccines. Recent advances in bioinspired delivery platforms for cancer vaccines, existing obstacles faced, as well as insights and future directions for the field are discussed here.

3D-to-3D Microscale Shape-Morphing from Configurable Helices with Controlled Chirality

Tunable and reconfigurable materials with autonomic shape transformation in response to the environment have emerged as one of the most promising approaches for a variety of biomedical applications, such as tissue engineering, biosensing, and in vivo biomedical devices. Currently, it is still quite challenging to fabricate soft, microscaled 3D shape-reconfigurable structures due to either complicated microfabrication or limited microscale photopolymerization-based printing approaches to enable adaptive shape transformation. Here, a one-step photo-cross-linking approach has been demonstrated to obtain a 3D-to-3D morphological transformable microhelix from a self-rolled hydrogel microsheet, resulting in chirality conversion. It was enabled by a custom-designed "hard" stripe/"soft" groove topography on the microsheets for introducing, which introduced both in-planar and out-of-planar anisotropies. Both experiment and simulation confirmed that a stripe/groove geometry can effectively control the 3D transformation by activating in-planar or/and out-of-planar mismatch stress within the microsheets, resulting in switching of the rolling direction between perpendicular/parallel to the length of the stripe. Furthermore, versatile 3D microconstructs with the ability to transform between two distinct 3D configurations have been achieved based on controlled rolling of microhelices, demonstrated as "windmill"-to-"T-cross" and "cylinder"-to-"scroll" transformations and dynamic blossoming of biomimetic orchids. In contrast to conventional 2D-to-3D micro-origami, we have successfully demonstrated an approach for fabricating microscale, all-soft-material-based constructs with autonomic 3D-to-3D structural transformation, which presents an opportunity for designing more complex hydrogel-based microrobotics.

Multifunctional Photoactive Hydrogels for Wound Healing Acceleration

Light is an attractive tool that has a profound impact on modern medicine. Particularly, light-based photothermal therapy (PTT) and photodynamic therapy (PDT) show great application prospects in the prevention of wound infection and promoting wound healing. In addition, hydrogels have shown attractive advantages in the field of wound dressings due to their excellent biochemical effects. Therefore, multifunctional photoresponsive hydrogels (MPRHs) that integrate the advantages of light and hydrogels are increasingly used in biomedicine, especially in the field of wound repair. However, a comprehensive review of MPRHs for wound regeneration is still lacking. This review first focuses on various types of MPRHs prepared by diverse photosensitizers, photothermal agents (PHTAs) including transition metal sulfide/oxides nanomaterials, metal nanostructure-based PHTAs, carbon-based PHTAs, conjugated polymer or complex-based PHTAs, and/or photodynamic agents (PHDAs) such as ZnO-based, black-phosphorus-based, TiO₂-based, and small organic molecule-based PHDAs. We also then discuss how PTT, PDT, and photothermal/photodynamic synergistic therapy can modulate the microenvironments of bacteria to inhibit infection. Overall, multifunctional hydrogels with both therapeutic and tissue regeneration capabilities have been discussed and existing challenges, as well as future research directions in the field of MPRHs and their application in wound management are argued.

Thermoresponsive Hydrogel Containing Viscum album Extract for Topic and Transdermal Use: Development, Stability and Cytotoxicity Activity

Viscum album L. (Santalaceae), also known as European mistletoe, is a semi-parasitic plant that grows on different host trees. Our group recently demonstrated the antitumoral activity of ethanolic V. album extracts in vitro, depending on the dose and the host tree, V. album ssp abietis from Abies alba being the most active extract. The goal of this work focused on the development of a new topical formulation containing V. album extracts, evaluation of in vitro toxicity and ex vivo skin permeation assays. The Poloxamer 407 hydrogel containing 5% of dry (VA_DEH) or aqueous (VA_AEH) extract presented dermal compatible pH and microbiological stability for 180 days. The hydrogels flow curve presented a non-linear relation, characteristic of non-Newtonian fluids, and the mean viscosity for the VA_DEH and VA_AEH was 372.5 ± 7.78 and 331.0 ± 2.83 Pa.s, respectively, being statistically different (Welch’s t test; p < 0.01). Additionally, WST-1 in vitro assays revealed a dose-dependent toxicity for both formulations and VA_DEH presented a higher activity than the VA_AEH. The promising cytotoxic potential of VA_DEH lead to the ex vivo skin permeation assay with 2.73 ± 0.19 µg/cm² of chlorogenic acid, which permeated at 8 h, showing a transdermal potential. These in vitro results support the idea that VA_DEH is a novel promising candidate for mistletoe therapy. Therefore, further in vivo and pre-clinical experiments should be performed to evaluate the safety and efficacy of this new dermic delivery system.

Review of Recent Advances and Their Improvement in the Effectiveness of Hydrogel-Based Targeted Drug Delivery: A Hope for Treating Cancer

Using hydrogels for delivering cancer therapeutics is advantageous in pharmaceutical usage as they have an edge over traditional delivery, which is tainted due to the risk of toxicity that it imbues. Hydrogel usage leads to the development of a more controlled drug release system owing to its amenability for structural metamorphosis, its higher porosity to seat the drug molecules, and its ability to shield the drug from denaturation. The thing that makes its utility even more enhanced is that they make themselves more recognizable to the body tissues and hence can stay inside the body for a longer time, enhancing the efficiency of the delivery, which otherwise is negatively affected since the drug is identified by the human immunity as a foreign substance, and thus, an attack of the immunity begins on the drug injected. A variety of hydrogels such as thermosensitive, pH-sensitive, and magnetism-responsive hydrogels have been included and their potential usage in drug delivery has been discussed in this review that aims to present recent studies on hydrogels that respond to alterations under a variety of circumstances in "reducing" situations that mimic the microenvironment of cancerous cells.