Application of ZnO-Based Nanocomposites for Vaccines and Cancer Immunotherapy

Breaking barriers: Smart vaccine platforms for cancer immunomodulation

Despite significant advancements in cancer treatment, current therapies often fail to completely eradicate malignant cells. This shortfall underscores the urgent need to explore alternative approaches such as cancer vaccines. Leveraging the immune system's natural ability to target and kill cancer cells holds great therapeutic potential. However, the development of cancer vaccines is hindered by several challenges, including low stability, inadequate immune response activation, and the immunosuppressive tumor microenvironment, which limit their efficacy. Recent progress in various fields, such as click chemistry, nanotechnology, exosome engineering, and neoantigen design, offer innovative solutions to these challenges. These achievements have led to the emergence of smart vaccine platforms (SVPs), which integrate protective carriers for messenger ribonucleic acid (mRNA) with functionalization strategies to optimize targeted delivery. Click chemistry further enhances SVP performance by improving the encapsulation of mRNA antigens and facilitating their precise delivery to target cells. This review highlights the latest developments in SVP technologies for cancer therapy, exploring both their opportunities and challenges in advancing these transformative approaches.

Use of Antimicrobial Nanoparticles for the Management of Dental Diseases

Dental diseases represent a significant global health concern, with traditional treatment methods often proving costly and lacking in long-term efficacy. Emerging research highlights nanoparticles as a promising, cost-effective therapeutic alternative, owing to their unique properties. This review aims to provide a comprehensive overview of the application of antimicrobial and antioxidant nanoparticles in the management of dental diseases. Silver and gold nanoparticles have shown great potential for inhibiting biofilm formation and thus preventing dental caries, gingivitis, and periodontitis. Various dental products can integrate copper nanoparticles, known for their antimicrobial properties, to combat oral infections. Similarly, zinc oxide nanoparticles enhance the antimicrobial performance of dental materials, including adhesives and cements. Titanium dioxide and cerium oxide nanoparticles possess antimicrobial and photocatalytic properties, rendering them advantageous for dental materials and oral hygiene products. Chitosan nanoparticles are effective in inhibiting oral pathogens and reducing inflammation in periodontal tissues. Additionally, curcumin nanoparticles, with their antimicrobial, anti-inflammatory, and antioxidant properties, can enhance the overall performance of dental materials and oral care products. Incorporating these diverse nanoparticles into dental materials and oral care products holds the potential to significantly reduce the risk of infection, control biofilm formation, and improve overall oral health. This review underscores the importance of continued research and development in this promising field to realize the full potential of nanoparticles in dental care.

Polypeptides-Based Nanocarriers in Tumor Therapy

Cancer remains a worldwide problem, and new treatment strategies are being actively developed. Peptides have the characteristics of good biocompatibility, strong targeting, functional diversity, modifiability, membrane permeable ability, and low immunogenicity, and they have been widely used to construct targeted drug delivery systems (DDSs). In addition, peptides, as endogenous substances, have a high affinity, which can not only regulate immune cells but also work synergistically with drugs to kill tumor cells, demonstrating significant potential for application. In this review, the latest progress of polypeptides-based nanocarriers in tumor therapy has been outlined, focusing on their applications in killing tumor cells and regulating immune cells. Additionally, peptides as carriers were found to primarily provide a transport function, which was also a subject of interest to us. At the end of the paper, the shortcomings in the construction of peptide nano-delivery system have been summarized, and possible solutions are proposed therein. The application of peptides provides a promising outlook for cancer treatment, and we hope this article can provide in-depth insights into possible future avenues of exploration.

Enhanced glioma cell death with ZnO nanorod flowers and temozolomide combination therapy through autophagy and mitophagy pathways

In recent years, the application of engineered NMts has significantly contributed to various biomedical fields. ZnO NMts (ZnO NMts) are widely utilized due to their biocompatibility, unique physical and chemical properties, stability, and cost-effectiveness for large-scale production. They have emerged as potential materials for anti-cancer applications. This study aims to study the impact of ZnO Nanorod flowers (ZnO NRfs) and their combination with temozolomide (TMZ) on glioma cells. Normal mouse microglia (BV2) will be used as a control to assess the effects on mouse glioma cells (G422) and human glioma cells (LN229). The effects of these substances were evaluated on G422 and LN229 cells through various parameters such as IC50 value, Zn2+ accumulation, ROS production, apoptosis, mitochondrial membrane potential (MMP) depolarization, and examination of organelles like mitochondria and lysosomes. Additionally, hypoxia-inducible factor-1α (HIF-1α), endothelial cell PAS domain protein 1 (EPAS1), autophagy markers (LC3), mitophagy and phagocytosis marker (BNIP3) were assessed. The results demonstrated that the combination of ZnO NRfs and TMZ could influence the expression of HIF-1α, EPAS1, LC3, and BNIP3 proteins, leading to mitophagy in glioma cells. This combination treatment has the potential to effectively eliminate glioma cells by activating the mitophagy pathway, which provides a good prospect for the clinical treatment of glioma.

Carboxymethylcellulose encapsulated fingolimod, siRNA@ZnO hybrid nanocomposite as a new anti-Alzheimer's material

Alzheimer's disease (AD) is a fatal neurological disorder that causes cognitive and memory function to deteriorate. A critical pathogenic event that speeds up the development of AD is the interaction between dysfunctional microglia and amyloid-β (Aβ). We have developed a hybrid nanocomposite material to treat AD by normalizing the dysfunctional microglia. The material is based on carboxymethylcellulose (CMC) encapsulated fingolimod, siRNA, and zinc oxide (ZnO) with variable loading (CMC-Fi-siRNA@ZnO a-d ). The material was characterized using different techniques including FTIR, XRD, thermal analysis, SEM with EDX, and TEM micrographs. The chemical structure was confirmed by FTIR and XRD analyses, which indicated the successful integration of ZnO nanoparticles (NPs) into the polymer matrix, signifying a well-formed composite structure. The thermal stability order at 10% weight loss was CMC-Fi-siRNA@ZnO c > CMC-Fi-siRNA@ZnO b > CMC-Fi-siRNA@ZnO d > CMC-Fi-siRNA@ZnO a . The CMC-Fi-siRNA@ZnO d dramatically alleviates the priming of microglia by lowering the level of proinflammatory mediators and increasing the secretion of BDNF. This considerably improves the phagocytosis of Aβ. In the cell viability test in immortalized microglia cells (IMG), the hybrid nanocomposite (NP) exhibited no significant effect on cell survival after 48 hours of incubation. The NP also decreased the cytotoxicity caused by Aβ. Therefore, the CMC-hybrid NP has high potential as a drug delivery system in the development of therapeutic strategies for AD.

Engineering mesoporous bioactive glasses for emerging stimuli-responsive drug delivery and theranostic applications

Mesoporous bioactive glasses (MBGs), which belong to the category of modern porous nanomaterials, have garnered significant attention due to their impressive biological activities, appealing physicochemical properties, and desirable morphological features. They hold immense potential for utilization in diverse fields, including adsorption, separation, catalysis, bioengineering, and medicine. Despite possessing interior porous structures, excellent morphological characteristics, and superior biocompatibility, primitive MBGs face challenges related to weak encapsulation efficiency, drug loading, and mechanical strength when applied in biomedical fields. It is important to note that the advantageous attributes of MBGs can be effectively preserved by incorporating supramolecular assemblies, miscellaneous metal species, and their conjugates into the material surfaces or intrinsic mesoporous networks. The innovative advancements in these modified colloidal inorganic nanocarriers inspire researchers to explore novel applications, such as stimuli-responsive drug delivery, with exceptional in-vivo performances. In view of the above, we outline the fabrication process of calcium-silicon-phosphorus based MBGs, followed by discussions on their significant progress in various engineered strategies involving surface functionalization, nanostructures, and network modification. Furthermore, we emphasize the recent advancements in the textural and physicochemical properties of MBGs, along with their theranostic potentials in multiple cancerous and non-cancerous diseases. Lastly, we recapitulate compelling viewpoints, with specific considerations given from bench to bedside.

A critical review on metal-organic frameworks (MOFs) based nanomaterials for biomedical applications: Designing, recent trends, challenges, and prospects

Nanomaterials (NMs) have garnered significant attention in recent decades due to their versatile applications in a wide range of fields. Thanks to their tiny size, enhanced surface modifications, impressive volume-to-surface area ratio, magnetic properties, and customized optical dispersion. NMs experienced an incredible upsurge in biomedical applications including diagnostics, therapeutics, and drug delivery. This minireview will focus on notable examples of NMs that tackle important issues, demonstrating various aspects such as their design, synthesis, morphology, classification, and use in cutting-edge applications. Furthermore, we have classified and outlined the distinctive characteristics of the advanced NMs as nanoscale particles and hybrid NMs. Meanwhile, we emphasize the incredible potential of metal-organic frameworks (MOFs), a highly versatile group of NMs. These MOFs have gained recognition as promising candidates for a wide range of bio-applications, including bioimaging, biosensing, antiviral therapy, anticancer therapy, nanomedicines, theranostics, immunotherapy, photodynamic therapy, photothermal therapy, gene therapy, and drug delivery. Although advanced NMs have shown great potential in the biomedical field, their use in clinical applications is still limited by issues such as stability, cytotoxicity, biocompatibility, and health concerns. This review article provides a thorough analysis offering valuable insights for researchers investigating to explore new design, development, and expansion opportunities. Remarkably, we ponder the prospects of NMs and nanocomposites in conjunction with current technology.

Polysaccharide from Atractylodes macrocephala Koidz Binding with Zinc Oxide Nanoparticles as a Novel Mucosal Immune Adjuvant for H9N2 Inactivated Vaccine

H9N2 avian influenza poses a significant public health risk, necessitating effective vaccines for mass immunization. Oral inactivated vaccines offer advantages like the ease of administration, but their efficacy often requires enhancement through mucosal adjuvants. In a previous study, we established a novel complex of polysaccharide from Atractylodes macrocephala Koidz binding with zinc oxide nanoparticles (AMP-ZnONPs) and preliminarily demonstrated its immune-enhancing function. This work aimed to evaluate the efficacy of AMP-ZnONPs as adjuvants in an oral H9N2-inactivated vaccine and the vaccine's impact on intestinal mucosal immunity. In this study, mice were orally vaccinated on days 0 and 14 after adapting to the environment. AMP-ZnONPs significantly improved HI titers, the levels of specific IgG, IgG1 and IgG2a in serum and sIgA in intestinal lavage fluid; increased the number of B-1 and B-2 cells and dendritic cell populations; and enhanced the mRNA expression of intestinal homing factors and immune-related cytokines. Interestingly, AMP-ZnONPs were more likely to affect B-1 cells than B-2 cells. AMP-ZnONPs showed mucosal immune enhancement that was comparable to positive control (cholera toxin, CT), but not to the side effect of weight loss caused by CT. Compared to the whole-inactivated H9N2 virus (WIV) group, the WIV + AMP-ZnONP and WIV + CT groups exhibited opposite shifts in gut microbial abundance. AMP-ZnONPs serve as an effective and safe mucosal adjuvant for oral WIV, improving cellular, humoral and mucosal immunity and microbiota in the gastrointestinal tract, avoiding the related undesired effects of CT.

Synthesis and characterization of 4-nitro benzaldehyde with ZnO-based nanoparticles for biomedical applications

Globally, cancer is the leading cause of death and morbidity, and skin cancer is the most common cancer diagnosis. Skin problems can be treated with nanoparticles (NPs), particularly with zinc oxide (ZnO) NPs, which have antioxidant, antibacterial, anti-inflammatory, and anticancer properties. An antibacterial activity of zinc oxide nanoparticles prepared in the presence of 4-nitrobenzaldehyde (4NB) was also tested in the present study. In addition, the influence of synthesized NPs on cell apoptosis, cell viability, mitochondrial membrane potential (MMP), endogenous reactive oxygen species (ROS) production, apoptosis, and cell adhesion was also examined. The synthesized 4-nitro benzaldehyde with ZnO (4NBZnO) NPs were confirmed via characterization techniques. 4NBZnO NPs showed superior antibacterial properties against the pathogens tested in antibacterial investigations. As a result of dose-based treatment with 4NBZnO NPs, cell viability, and MMP activity of melanoma cells (SK-MEL-3) cells were suppressed. A dose-dependent accumulation of ROS was observed in cells exposed to 4NBZnO NPs. As a result of exposure to 4NBZnO NPs in a dose-dependent manner, viable cells declined and apoptotic cells increased. This indicates that apoptotic cell death was higher. The cell adhesion test revealed that 4NBZnO NPs reduced cell adhesion and may promote apoptosis of cancer cells because of enhanced ROS levels.

The advancing of polymeric core-shell ZnO nanocomposites containing 5-fluorouracil for improving anticancer activity in colorectal cancer

The study investigated the use of 5-fluorouracil-loaded ZnO nanocomposites (5-FU/Gd-ZnO NCs) as a potential treatment for cancer. 5-FU is a commonly used drug for cancer treatment but has undesirable side effects. The materials were characterized using various techniques, including PXRD, FTIR, FESEM, TEM, DLS, £-potential, and AFM. The data showed that the nanocomposites had a plate-like agglomeration with particle diameters ranging from 317.6 to 120.1 nm. The IC50 value of 5-FU-ZnO, which inhibits cell growth, was found to be 1.85 ppm. The effects of 5-FU-ZnO on inflammatory markers were also examined. While 5-FU increased the levels of TNF-a and IL-1b, the nanocomposites were able to reduce these levels. Additionally, the 5-FU/Gd-ZnO-NCs group showed an increase in thiol levels and a decrease in catalase and superoxide dismutase levels. Flow cytometry results showed that 5-FU, ZnO-NCs, and 5-FU/Gd-ZnO-NCs did not have any additive or synergistic effects on the suppression or eradication of cancer cells. In vivo, experiments showed that the 5-FU/Gd-ZnO NCs had similar necrotic characteristics and reduced fibrosis and collagen deposition compared to the free medication. The nanocomposites also exhibited higher antioxidative activity and lower inflammatory responses compared to the 5-FU group. It was shown that 5-FU/Gd-ZnO-NCs successfully inhibit cell proliferation. The in vivo results were comparable to those obtained with free 5-FU, suggesting the potential of these nanocomposites as therapeutic agents.

Multifunctional nanocomposites modulating the tumor microenvironment for enhanced cancer immunotherapy

Cancer immunotherapy has gained momentum for treating malignant tumors over the past decade. Checkpoint blockade and chimeric antigen receptor cell therapy (CAR-T) have shown considerable potency against liquid and solid cancers. However, the tumor microenvironment (TME) is highly immunosuppressive and hampers the effect of currently available cancer immunotherapies on overall treatment outcomes. Advancements in the design and engineering of nanomaterials have opened new avenues to modulate the TME. Progress in the current nanocomposite technology can overcome immunosuppression and trigger robust immunotherapeutic responses by integrating synergistic functions of different molecules. We will review recent advancements in nanomedical applications and discuss specifically designed nanocomposites modulating the TME for cancer immunotherapy. In addition, we provide information on the current landscape of clinical-stage nanocomposites for cancer immunotherapy.

ZnO nanomaterials target mitochondrial apoptosis and mitochondrial autophagy pathways in cancer cells

In recent years, the application of engineering nanomaterials has significantly contributed to the development of various biomedical fields. Zinc oxide nanomaterials (ZnO NMts) have gained wide popularity due to their biocompatibility, unique physical and chemical properties, stability, and cost-effectiveness for large-scale production. They have emerged as potential materials for anticancer applications. This article provides a comprehensive review of the synthesis methods of ZnO NMts and highlights the advantages of combining ZnO NMts with anticancer drugs as a nano platform for cancer treatment. Additionally, the article briefly explains the mechanism of action of ZnO NMts in tumor cells, focusing on the mitochondrial pathways that target cell apoptosis and autophagy. It is observed that these pathways are primarily influenced by reactive oxygen species generated through oxidative stress. The article discusses the promising prospects of ZnO NMts combined with anticancer drugs in the field of cancer medicine and emphasizes the need for further in-depth research on the mitochondrial apoptosis and mitochondrial autophagy pathways.

Recent Advances in ZnO Nanomaterial-Mediated Biological Applications and Action Mechanisms

In recent years, with the deepening research, metal zinc oxide (ZnO) nanomaterials have become a popular research object in the biological field, particularly in biomedicine and food safety, which is attributed to their unique physicochemical properties such as high surface area and volume ratio, luminescence effect, surface characteristics and biological activities. Herein, this review provides a detailed overview of the ZnO nanomaterial-mediated biological applications that involve anti-bacterial, anti-tumor, anti-inflammation, skin care, biological imaging and food packaging applications. Importantly, the corresponding action mechanisms of ZnO nanomaterials are pointed. Additionally, the structure and structure-dependent physicochemical properties, the common synthesis methods and the biosafety of ZnO nanoparticles are revealed in brief. Finally, the significance and future challenges of ZnO nanomaterial applications are concluded.

The advance anticancer role of polymeric core-shell ZnO nanoparticles containing oxaliplatin in colorectal cancer

We evaluated the activity of core-shell ZnO nanoparticles (ZnO-NPs@polymer shell) containing Oxaliplatin via polymerization through in vitro studies and in vivo mouse models of colorectal cancer. ZnO NPs were synthesized in situ when the polymerization step was completed by co-precipitation. Gadolinium coordinated-ZnONPs@polymer shell (ZnO-Gd NPs@polymer shell) was synthesized by exploiting Gd's oxophilicity (III). The biophysical properties of the NPs were studied using powder X-ray diffraction (PXRD), Fourier transforms infrared spectroscopy, Ultraviolet-visible spectroscopy (UV-Vis), field emission electron microscopy (FESEM), transmission electron microscopy (TEM), atomic force microscopy, dynamic light scattering, and z-potential. (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) was used to determine the antiproliferative activity of ZnO-Gd-OXA. Moreover, a xenograft mouse model of colon cancer was exerted to survey its antitumor activity and effect on tumor growth. In the following, the model was also evaluated by histological staining (H-E; Hematoxylin & Eosin and trichrome staining) and gene expression analyses through the application of RT-PCR/ELISA, which included biochemical evaluation (MDA, thiols, SOD, CAT). The formation of ZnO NPs, which contained a crystallite size of 16.8 nm, was confirmed by the outcomes of the PXRD analysis. The Plate-like morphology and presence of Pt were obtained in EDX outcomes. TEM analysis displayed the attained ZnO NPs in a spherical shape and a diameter of 33 ± 8.5 nm, while the hydrodynamic sizes indicated that the particles were highly aggregated. The biological results demonstrated that ZnO-Gd-OXA inhibited tumor growth by inducing reactive oxygen species and inhibiting fibrosis, warranting further research on this novel colorectal cancer treatment agent.

Emerging applications of nanotechnology in context to immunology: A comprehensive review

Numerous benefits of nanotechnology are available in many scientific domains. In this sense, nanoparticles serve as the fundamental foundation of nanotechnology. Recent developments in nanotechnology have demonstrated that nanoparticles have enormous promise for use in almost every field of life sciences. Nanoscience and nanotechnology use the distinctive characteristics of tiny nanoparticles (NPs) for various purposes in electronics, fabrics, cosmetics, biopharmaceutical industries, and medicines. The exclusive physical, chemical, and biological characteristics of nanoparticles prompt different immune responses in the body. Nanoparticles are believed to have strong potential for the development of advanced adjuvants, cytokines, vaccines, drugs, immunotherapies, and theranostic applications for the treatment of targeted bacterial, fungal, viral, and allergic diseases and removal of the tumor with minimal toxicity as compared to macro and microstructures. This review highlights the medical and non-medical applications with a detailed discussion on enhanced and targeted natural and acquired immunity against pathogens provoked by nanoparticles. The immunological aspects of the nanotechnology field are beyond the scope of this Review. However, we provide updated data that will explore novel theragnostic immunological applications of nanotechnology for better and immediate treatment.

Cytotoxicity of Metal-Based Nanoparticles: From Mechanisms and Methods of Evaluation to Pathological Manifestations

Metal-based nanoparticles (NPs) are particularly important tools in tissue engineering-, drug carrier-, interventional therapy-, and biobased technologies. However, their complex and varied migration and transformation pathways, as well as their continuous accumulation in closed biological systems, cause various unpredictable toxic effects that threaten human and ecosystem health. Considerable experimental and theoretical efforts have been made toward understanding these cytotoxic effects, though more research on metal-based NPs integrated with clinical medicine is required. This review summarizes the mechanisms and evaluation methods of cytotoxicity and provides an in-depth analysis of the typical effects generated in the nervous, immune, reproductive, and genetic systems. In addition, the challenges and opportunities are discussed to enhance future investigations on safer metal-based NPs for practical commercial adoption.

Zinc Oxide Nanoparticles and Their Biosynthesis: Overview

Zinc (Zn) is plant micronutrient, which is involved in many physiological functions, and an inadequate supply will reduce crop yields. Its deficiency is the widest spread micronutrient deficiency problem; almost all crops and calcareous, sandy soils, as well as peat soils and soils with high phosphorus and silicon content are expected to be deficient. In addition, Zn is essential for growth in animals, human beings, and plants; it is vital to crop nutrition as it is required in various enzymatic reactions, metabolic processes, and oxidation reduction reactions. Finally, there is a lot of attention on the Zn nanoparticles (NPs) due to our understanding of different forms of Zn, as well as its uptake and integration in the plants, which could be the primary step toward the larger use of NPs of Zn in agriculture. Nanotechnology application in agriculture has been increasing over recent years and constitutes a valuable tool in reaching the goal of sustainable food production worldwide. A wide array of nanomaterials has been used to develop strategies of delivery of bioactive compounds aimed at boosting the production and protection of crops. ZnO-NPs, a multifunctional material with distinct properties and their doped counterparts, were widely being studied in different fields of science. However, its application in environmental waste treatment and many other managements, such as remediation, is starting to gain attention due to its low cost and high productivity. Nano-agrochemicals are a combination of nanotechnology with agrochemicals that have resulted in nano-fertilizers, nano-herbicides, nano-fungicides, nano-pesticides, and nano-insecticides being developed. They have anti-bacterial, anti-fungal, anti-inflammatory, antioxidant, and optical capabilities. Green approaches using plants, fungi, bacteria, and algae have been implemented due to the high rate of harmful chemicals and severe situations used in the manufacturing of the NPs. This review summarizes the data on Zn interaction with plants and contributes towards the knowledge of Zn NPs and its impact on plants.

Zinc associated nanomaterials and their intervention in emerging respiratory viruses: Journey to the field of biomedicine and biomaterials

Respiratory viruses represent a severe public health risk worldwide, and the research contribution to tackle the current pandemic caused by the SARS-CoV-2 is one of the main targets among the scientific community. In this regard, experts from different fields have gathered to confront this catastrophic pandemic. This review illustrates how nanotechnology intervention could be valuable in solving this difficult situation, and the state of the art of Zn-based nanostructures are discussed in detail. For virus detection, learning from the experience of other respiratory viruses such as influenza, the potential use of Zn nanomaterials as suitable sensing platforms to recognize the S1 spike protein in SARS-CoV-2 are shown. Furthermore, a discussion about the antiviral mechanisms reported for ZnO nanostructures is included, which can help develop surface disinfectants and protective coatings. At the same time, the properties of Zn-based materials as supplements for reducing viral activity and the recovery of infected patients are illustrated. Within the scope of noble adjuvants to improve the immune response, the ZnO NPs properties as immunomodulators are explained, and potential prototypes of nanoengineered particles with metallic cations (like Zn2+) are suggested. Therefore, using Zn-associated nanomaterials from detection to disinfection, supplementation, and immunomodulation opens a wide area of opportunities to combat these emerging respiratory viruses. Finally, the attractive properties of these nanomaterials can be extrapolated to new clinical challenges.

Nano dimensions/adjuvants in COVID-19 vaccines

A favorable outcome of the COVID-19 crisis might be achieved with massive vaccination. The proposed vaccines contain several different vaccine active principles (VAP), such as inactivated virus, antigen, mRNA, and DNA, which are associated with either standard adjuvants or nanomaterials (NM) such as liposomes in Moderna's and BioNTech/Pfizer's vaccines. COVID-19 vaccine adjuvants may be chosen among liposomes or other types of NM composed for example of graphene oxide, carbon nanotubes, micelles, exosomes, membrane vesicles, polymers, or metallic NM, taking inspiration from cancer nano-vaccines, whose adjuvants may share some of their properties with those of viral vaccines. The mechanisms of action of nano-adjuvants are based on the facilitation by NM of targeting certain regions of immune interest such as the mucus, lymph nodes, and zones of infection or blood irrigation, the possible modulation of the type of attachment of the VAP to NM, in particular VAP positioning on the NM external surface to favor VAP presentation to antigen presenting cells (APC) or VAP encapsulation within NM to prevent VAP degradation, and the possibility to adjust the nature of the immune response by tuning the physico-chemical properties of NM such as their size, surface charge, or composition. The use of NM as adjuvants or the presence of nano-dimensions in COVID-19 vaccines does not only have the potential to improve the vaccine benefit/risk ratio, but also to reduce the dose of vaccine necessary to reach full efficacy. It could therefore ease the overall spread of COVID-19 vaccines within a sufficiently large portion of the world population to exit the current crisis.

Engineering Optimal Vaccination Strategies: Effects of Physical Properties of the Delivery System on Functions

With rapid developments in medical science and technology, vaccinations have become the key to solving public health problems. Various diseases can be prevented by vaccinations, which mimic a disease by...

ZnO-based multifunctional nanocomposites to inhibit progression and metastasis of melanoma by eliciting antitumor immunity via immunogenic cell death

Rationale: The development of a highly effective and tumor-specific therapeutic strategy, which can act against the primary tumor and also condition the host immune system to eliminate distant tumors, remains a clinical challenge.

Methods: Herein, we demonstrate a facile yet versatile ZnO-capping and Doxorubicin (DOX)-loaded multifunctional nanocomposite (AuNP@mSiO₂@DOX-ZnO) that integrates photothermal properties of gold nanoparticles (NPs), pH-responsive properties and preferential selectivity to tumor cells of ZnO QDs and chemotherapeutic agent into a single NP. The photothermal performance, pH-triggered release and preferential phagocytic ability were assessed. The induced anti-tumor immunity was determined by analyzing immune cell profile in tumor in vivo and molecular mechanism were identified by detecting expression of immunogenic cell death (ICD) markers in vitro. Moreover, mice models of unilateral and bilateral subcutaneous melanoma and lung metastasis were established to evaluate the antitumor effects.

Results: As an efficient drug carrier, ZnO-capped NPs guarantee a high DOX payload and an in vitro, efficient release of at pH 5.0. In murine melanoma models, the nanocomposite can significantly inhibit tumor growth for a short period upon low-power laser irradiation. Importantly, ZnO NPs not only demonstrate preferential selectivity for melanoma cells but can also induce ICD. Meanwhile, AuNP@mSiO₂-based photothermal therapy (PTT) and DOX are directly cytotoxic towards cancer cells and demonstrate an elevated ICD effect. The induced ICD promotes maturation of dendritic cells, further stimulating the infiltration of effector T cells into tumor sites, preventing tumor growth and distant lung metastases.

Conclusions: This study highlights the novel mechanism of ZnO-triggered anti-tumor immunity via inducing ICD. Additionally, we shed light on the multifunctionality of nanocomposites in delivering localized skin tumor therapy as well as inhibiting metastatic growth, which holds great promise in clinical applications.

Metal Oxide Nanoparticles as Biomedical Materials

The development of new nanomaterials with high biomedical performance and low toxicity is essential to obtain more efficient therapy and precise diagnostic tools and devices. Recently, scientists often face issues of balancing between positive therapeutic effects of metal oxide nanoparticles and their toxic side effects. In this review, considering metal oxide nanoparticles as important technological and biomedical materials, the authors provide a comprehensive review of researches on metal oxide nanoparticles, their nanoscale physicochemical properties, defining specific applications in the various fields of nanomedicine. Authors discuss the recent development of metal oxide nanoparticles that were employed as biomedical materials in tissue therapy, immunotherapy, diagnosis, dentistry, regenerative medicine, wound healing and biosensing platforms. Besides, their antimicrobial, antifungal, antiviral properties along with biotoxicology were debated in detail. The significant breakthroughs in the field of nanobiomedicine have emerged in areas and numbers predicting tremendous application potential and enormous market value for metal oxide nanoparticles.

A Review of Microwave Synthesis of Zinc Oxide Nanomaterials: Reactants, Process Parameters and Morphoslogies

Zinc oxide (ZnO) is a multifunctional material due to its exceptional physicochemical properties and broad usefulness. The special properties resulting from the reduction of the material size from the macro scale to the nano scale has made the application of ZnO nanomaterials (ZnO NMs) more popular in numerous consumer products. In recent years, particular attention has been drawn to the development of various methods of ZnO NMs synthesis, which above all meet the requirements of the green chemistry approach. The application of the microwave heating technology when obtaining ZnO NMs enables the development of new methods of syntheses, which are characterised by, among others, the possibility to control the properties, repeatability, reproducibility, short synthesis duration, low price, purity, and fulfilment of the eco-friendly approach criterion. The dynamic development of materials engineering is the reason why it is necessary to obtain ZnO NMs with strictly defined properties. The present review aims to discuss the state of the art regarding the microwave synthesis of undoped and doped ZnO NMs. The first part of the review presents the properties of ZnO and new applications of ZnO NMs. Subsequently, the properties of microwave heating are discussed and compared with conventional heating and areas of application are presented. The final part of the paper presents reactants, parameters of processes, and the morphology of products, with a division of the microwave synthesis of ZnO NMs into three primary groups, namely hydrothermal, solvothermal, and hybrid methods.

Nanoparticles to Improve the Efficacy of Vaccines

This editorial aims to summarize the nine scientific papers that contributed to the Special Issue entitled 'Nanoparticles to Improve the Efficacy of Vaccines'.