Nanoemulsions: Formulation, characterization, biological fate, and potential role against COVID-19 and other viral outbreaks

Curcumin and quercetin co-encapsulated in nanoemulsions for nasal administration: A promising therapeutic and prophylactic treatment for viral respiratory infections

One of the most frequent causes of respiratory infections are viruses. Viruses reaching the airways can be absorbed by the human body through the respiratory mucosa and mainly infect lung cells. Several viral infections are not yet curable, such as coronavirus-2 (SARS-CoV-2). Furthermore, the side effect of synthetic antiviral drugs and reduced efficacy against resistant variants have reinforced the search for alternative and effective treatment options, such as plant-derived antiviral molecules. Curcumin (CUR) and quercetin (QUE) are two natural compounds that have been widely studied for their health benefits, such as antiviral and anti-inflammatory activity. However, poor oral bioavailability limits the clinical applications of these natural compounds. In this work, nanoemulsions (NE) co-encapsulating CUR and QUE designed for nasal administration were developed as promising prophylactic and therapeutic treatments for viral respiratory infections. The NEs were prepared by high-pressure homogenization combined with the phase inversion temperature technique and evaluated for their physical and chemical characteristics. In vitro assays were performed to evaluate the nanoemulsion retention into the porcine nasal mucosa. In addition, the CUR and QUE-loaded NE antiviral activity was tested against a murine β-COV, namely MHV-3. The results evidenced that CUR and QUE loaded NE had a particle size of 400 nm and retention in the porcine nasal mucosa. The antiviral activity of the NEs showed a percentage of inhibition of around 99 %, indicating that the developed NEs has interesting properties as a therapeutic and prophylactic treatment against viral respiratory infections.

Nanomaterial-Driven Precision Immunomodulation: A New Paradigm in Therapeutic Interventions

Immunotherapy is a rapidly advancing field of research in the treatment of conditions such as cancer and autoimmunity. Nanomaterials can be designed for immune system manipulation, with precise targeted delivery and improved immunomodulatory efficacy. Here, we elaborate on various strategies using nanomaterials, including liposomes, polymers, and inorganic NPs, and discuss their detailed design intricacies, mechanisms, and applications, including the current regulatory issues. This type of nanomaterial design for targeting specific immune cells or tissues and controlling release kinetics could push current technological frontiers and provide new and innovative solutions for immune-related disorders and diseases without off-target effects. These materials enable targeted interactions with immune cells, thereby enhancing the effectiveness of checkpoint inhibitors, cancer vaccines, and adoptive cell therapies. Moreover, they allow for fine-tuning of immune responses while minimizing side effects. At the intersection of nanotechnology and immunology, nanomaterial-based platforms have immense potential to revolutionize patient-centered immunotherapy and reshape disease management. By prioritizing safety, customization, and compliance with regulatory standards, these systems can make significant contributions to precision medicine, thereby significantly impacting the healthcare landscape.

Potential Activity of Micafungin and Amphotericin B Co-Encapsulated in Nanoemulsion against Systemic Candida auris Infection in a Mice Model

The Candida auris species is a multidrug-resistant yeast capable of causing systemic and lethal infections. Its virulence and increase in outbreaks are a global concern, especially in hospitals where outbreaks are more recurrent. In many cases, monotherapy is not effective, and drug combinations are opted for. However, resistance to antifungals has increased over the years. In view of this, nanoemulsions (NEs) may represent a nanotechnology strategy in the development of new therapeutic alternatives. Therefore, this study developed a co-encapsulated nanoemulsion with amphotericin B (AmB) and micafungin (MICA) (NEMA) for the control of infections caused by C. auris. NEs were developed in previous studies. Briefly, the NEs were composed of a mixture of 10% sunflower oil and cholesterol as the oil phase (5:1), 10% Polyoxyethylene (20) cetyl ether (Brij® 58) and soy phosphatidylcholine as surfactant/co-surfactant (2:1), and 80% PBS as the aqueous phase. The in vivo assay used BALB/c mice weighing between 25 and 28 g that were immunosuppressed (CEUA/FCF/CAr n° 29/2021) and infected with Candida auris CDC B11903. The in vivo results show the surprising potentiate of the antifungal activity of the co-encapsulated drugs in NE, preventing yeast from causing infection in the lung and thymus. Biochemical assays showed a higher concentration of liver and kidney enzymes under treatment with AmB and MICAmB. In conclusion, this combination of drugs to combat the infection caused by C. auris can be considered an efficient therapeutic option, and nanoemulsions contribute to therapeutic potentiate, proving to be a promising new alternative.

Chia nanoemulsion: anti-inflammatory mechanism, biological behavior and cellular interactions

Aim: This study explores chia oil, rich in ω-3 fatty acids and nutraceutical components, as a potential remedy for diseases, especially those linked to inflammation and cancer. Methods/materials: A chia oil-based nanoemulsion, developed through single emulsification, underwent comprehensive analysis using various techniques. In vitro and in vivo assays, including macrophage polarization, nitrite and cytokine production, cellular uptake and biodistribution, were conducted to assess the anti-inflammatory efficacy. Results & conclusion: Results reveal that the chia nanoemulsion significantly inhibits inflammation, outperforming pure oil with twice the efficacy. Enhanced uptake by macrophage-like cells and substantial accumulation in key organs indicate its potential as an economical and effective anti-inflammatory nanodrug, addressing global economic and health impacts of inflammation-related diseases.

Formulation and in vitro characterization of nanoemulsions containing remdesivir or licorice extract: A potential subcutaneous injection for coronavirus treatment

The management of coronavirus necessitates that medicines are available, reasonably priced, and easy to administer. The work aimed at formulating and characterizing remdesivir and licorice extract nanoemulsions and comparing their efficacy against coronavirus for further subcutaneous injection. First, the solubility of remdesivir was determined in different oils, surfactants, and co-surfactants to choose the optimal nanoemulsion components. Nanoemulsions were optimized concerning surfactant: co-surfactant ratio (5:1, 4:1, 3:1, 2:1, and 1:1) and oil to surfactant: co-surfactant ratio (1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, and 1:1). The formulations were evaluated concerning % transmittance, emulsification time, pH, viscosity, droplet size, polydispersity index, zeta potential, drug content, transmission electron microscopy, in-vitro drug release, stability (of the optimal formulas), and antiviral effect against coronavirus. The optimal nanoemulsion formula was F7, exhibiting an acceptable pH level, a rapid emulsification rate, a viscosity of 20 cP, and 100% drug content. The formulation droplet size was 16 and 17 nm, the polydispersity index was 0.18 and 0.26, and the zeta potential was - 6.29 and - 10.34 mV for licorice extract and remdesivir nanoemulsions, respectively. However, licorice extract nanoemulsion exhibited better release and physical stability. Licorice extract nanoemulsion may be a potential subcutaneous injection for combating mild to moderate coronavirus.

Evaluating the effects of surfactant types on the properties and stability of oil-in-water Rhodiola rosea nanoemulsion

Different types and ratios of surfactant, co-surfactant, and oil phase, have a greater impact on nanoemulsion preparation. The presence of surfactants in the nanoemulsion can reduce surface tension and characteristic stability. In this study, four groups of oil-in-water (O/W) nanoemulsions (NEs) with different ratios of surfactant and co-surfactant, and two oils were formulated as carriers of Rhodiola rosea. The variable optimization was investigated and then indicated as optimization group A (Opt A) with the formula of 10% of transcutol, 16.63% of tween 80, Opt B with 10% of tween 80, 29.87% of span 80, Opt C with 28.42% of transcutol, 30% of labrasol, and Opt D with 30% of transcutol, 30% of tween 80. Labrafac and soybean oil were used as the oil phase. The optimized formula using the response surface method (RSM) by design expert software showed the ideal conditions with a higher desirability score. Desirability score are 0.72% (Opt A), 0.81% (Opt B), 0.76% (Opt C) and 0.98% (Opt D), the desirability rating close to 1 indicates a high possibility that the projected values would closely match the experimental results for the optimum formula. All of the optimized formulation were also checked for the characteristics of nanoemulsion including particle size, polydispersity index (PDI), zeta potential, viscosity, encapsulation efficiency, transmission electron microscope (TEM), antioxidant activity, skin irritation test and stability studies. Our study provides a promising combination of surfactant-co-surfactant and oil phases to produce a stable nanoemulsion that can be used in pharmaceuticals and cosmetics in the future.

Antimicrobial and anti-aflatoxigenic activities of nanoemulsions based on Achillea millefolium and Crocus sativus flower extracts as green promising agents for food preservatives

BACKGROUND

Although the mechanism of action of nanoemulsion is still unclear, the modern use of nanoemulsions made from natural extracts as antimicrobial and anti-aflatoxigenic agents represents a potential food preservation and a safety target.

METHODS

Two natural nanoemulsion extracts of Crocus sativus (the saffron flower) and Achillea millefolium (the yarrow flower) were produced in the current study using a low-energy method that included carboxymethylcellulose and Arabic gum. The synthesized nanoemulsion was fully identified by different analytical methods. Detection of the volatile content was completed using GC-MS analysis. The antioxidant potential, and phenolic compounds content were analyzed in the extractions. The synthesized nanoemulsions were screened for their antimicrobial potential in addition to their anti-aflatoxigenic activity.

RESULTS

The droplet size of Saffron flowers was finer (121.64 ± 2.18 nm) than yarrow flowers (151.21 ± 1.12 nm). The Zeta potential measurements of the yarrow flower (-16.31 ± 2.54 mV) and the saffron flower (-18.55 ± 2.31 mV) both showed high stability, along with low PDI values (0.34-0.41). The nanoemulsion of yarrow flower revealed 51 compounds using gas chromatography-mass spectrometry (GCMS), with hexanal (16.25%), β-Pinene (7.41%), β-Myrcene (5.24%), D-Limonene (5.58%) and Caryophyllene (4.38%) being the most prevalent. Additionally, 31 compounds were detected in the saffron nanoemulsion, with D-limonene (4.89%), isophorone (12.29%), 4-oxy isophorone (8.19%), and safranal (44.84%) being the most abundant. Compared to the nanoemulsion of the yarrow flower, the saffron nanoemulsion had good antibacterial and antifungal activity. Saffron nanoemulsion inhibited total fungal growth by 69.64-71.90% in a simulated liquid medium and demonstrated the most significant decrease in aflatoxin production. Infected strawberry fruits coated with nanoemulsion extracts exhibited high antimicrobial activity in the form of saffron flower and yarrow flower extract nanoemulsions, which inhibited and/or controlled the growth of Aspergillus fungi. Due to this inhibition, the lag phase was noticeably prolonged, the cell load decreased, and the stability time increased.

CONCLUSION

This study will contribute to expanding the theoretical research and utilization of nanoemulsions as green protective agents in agricultural and food industries for a promising protection from the invasion of some pathogenic bacteria and fungi.

Development and Optimization of a Novel Lozenge Containing a Metronidazole-Peppermint Oil-Tranexamic Acid Self-Nanoemulsified Delivery System to Be Used after Dental Extraction: In Vitro Evaluation and In Vivo Appraisal

In-depth studies on essential oil-based nanoemulsions (NEs) have centered on a variety of oral health issues. NEs improve the delivery of nonpolar active agents to sites and thereby boost the dissolution and distribution of the agents. Metronidazole-peppermint oil-tranexamic acid self-nanoemulsifying drug delivery systems (MZ-PO-TX-SNEDDS) were created and loaded into novel lozenges to act as antifungal, hemostatic, antimicrobial, and analgesic dosage forms after dental extractions. The design-of-experiments approach was used in creating them. To generate the NEs, different concentrations of MZ-PO (240, 180, and 120 mg), 2% TX (600, 450, and 300 mg), and Smix1:1 (600, 400, and 200 mg) were used. The ideal formulation had serum levels of 1530 U/mL of interleukin-6, a minimal inhibitory concentration against bacteria of 1.5 µg/mL, a droplet size of 96 nm, and a blood coagulation time of 16.5 min. Moreover, the produced NE offered better MZ release. The adopted design was used to produce the ideal formulation; it contained 240 mg of MZ-PO, 600 mg of 2% TX, and 600 mg of Smix1:1. It was incorporated into lozenges with acceptable characteristics and an improved capability for drug release. These lozenges had reasonable coagulation times, IL-6 serum levels, and MIC values. All of these characteristics are desirable for managing symptoms following tooth extractions. Therefore, these lozenges loaded with MZ-PO-TX-SNEDDs might be considered a beneficial paradigm for relieving complications encountered after tooth extractions.

Nano-based formulations of curcumin: elucidating the potential benefits and future prospects in skin cancer

Skin cancer refers to any malignant lesions that occur in the skin and are observed predominantly in populations of European descent. Conventional treatment modalities such as excision biopsy, chemotherapy, radiotherapy, immunotherapy, electrodesiccation, and photodynamic therapy (PDT) induce several unintended side effects which affect a patient's quality of life and physical well-being. Therefore, spice-derived nutraceuticals like curcumin, which are well tolerated, less expensive, and relatively safe, have been considered a promising agent for skin cancer treatment. Curcumin, a chemical constituent extracted from the Indian spice, turmeric, and its analogues has been used in various mammalian cancers including skin cancer. Curcumin has anti-neoplastic activity by triggering the process of apoptosis and preventing the multiplication and infiltration of the cancer cells by inhibiting some signaling pathways and thus subsequently preventing the process of carcinogenesis. Curcumin is also a photosensitizer and has been used in PDT. The major limitations associated with curcumin are poor bioavailability, instability, limited permeation into the skin, and lack of solubility in water. This will constrain the use of curcumin in clinical settings. Hence, developing a proper formulation that can ideally release curcumin to its targeted site is important. So, several nanoformulations based on curcumin have been established such as nanogels, nanoemulsions, nanofibers, nanopatterned films, nanoliposomes and nanoniosomes, nanodisks, and cyclodextrins. The present review mainly focuses on curcumin and its analogues as therapeutic agents for treating different types of skin cancers. The significance of using various nanoformulations as well non-nanoformulations loaded with curcumin as an effective treatment modality for skin cancer is also emphasized.

Advancement in Solubilization Approaches: A Step towards Bioavailability Enhancement of Poorly Soluble Drugs

A drug's aqueous solubility is defined as the ability to dissolve in a particular solvent, and it is currently a major hurdle in bringing new drug molecules to the market. According to some estimates, up to 40% of commercialized products and 70-90% of drug candidates in the development stage are poorly soluble, which results in low bioavailability, diminished therapeutic effects, and dosage escalation. Because of this, solubility must be taken into consideration when developing and fabricating pharmaceutical products. To date, a number of approaches have been investigated to address the problem of poor solubility. This review article attempts to summarize several conventional methods utilized to increase the solubility of poorly soluble drugs. These methods include the principles of physical and chemical approaches such as particle size reduction, solid dispersion, supercritical fluid technology, cryogenic technology, inclusion complex formation techniques, and floating granules. It includes structural modification (i.e., prodrug, salt formation, co-crystallization, use of co-solvents, hydrotrophy, polymorphs, amorphous solid dispersions, and pH variation). Various nanotechnological approaches such as liposomes, nanoparticles, dendrimers, micelles, metal organic frameworks, nanogels, nanoemulsions, nanosuspension, carbon nanotubes, and so forth have also been widely investigated for solubility enhancement. All these approaches have brought forward the enhancement of the bioavailability of orally administered drugs by improving the solubility of poorly water-soluble drugs. However, the solubility issues have not been completely resolved, owing to several challenges associated with current approaches, such as reproducibility in large scale production. Considering that there is no universal approach for solving solubility issues, more research is needed to simplify the existing technologies, which could increase the number of commercially available products employing these techniques.

D-limonene nanoemulsion: lousicidal activity, stability, and effect on the cuticle of Columbicola columbae

The current study was conducted to investigate the efficacy and stability of D-limonene (DL) and its nanoemulsion (DLN) against pigeon feather lice (Columbicola columbae) and their mode of action. DL pure form and DLN were prepared and characterized freshly and after storage for 50 days. In vitro bioassay on live lice was conducted with different concentrations of DL, DLN, and deltamethrin (DM). The results revealed significant mortality rates in the DL-, DLN-, DM-treated groups when compared with the control (p < 0.05). The scanning electron micrographs of lice treated with DL and DLN revealed collapsed bodies with destruction in the cuticle of the mouthparts and damaged antennae. The 50 days stored DLN showed stability in their effectiveness when compared with the freshly prepared formulation. DL and DLN caused significant inhibition (p ≤ 0.05) in acetylcholinesterase activity (AchE). Malondialdehyde level (MDA) was significantly increased while glutathione was significantly decreased in DL- and DLN-treated lice. In conclusion, DL and DLN have significant lousicidal activities. DLN showed better stability than DL after storage for 50 days. In addition, the mode of action of DL may associate with its effect on the cuticle of the lice body, inhibition of AchE, and increasing oxidative stress in the treated lice.

Caenorhabditis elegans as a Prediction Platform for Nanotechnology-Based Strategies: Insights on Analytical Challenges

Nanotechnology-based strategies have played a pivotal role in innovative products in different technological fields, including medicine, agriculture, and engineering. The redesign of the nanometric scale has improved drug targeting and delivery, diagnosis, water treatment, and analytical methods. Although efficiency brings benefits, toxicity in organisms and the environment is a concern, particularly in light of global climate change and plastic disposal in the environment. Therefore, to measure such effects, alternative models enable the assessment of impacts on both functional properties and toxicity. Caenorhabditis elegans is a nematode model that poses valuable advantages such as transparency, sensibility in responding to exogenous compounds, fast response to perturbations besides the possibility to replicate human disease through transgenics. Herein, we discuss the applications of C. elegans to nanomaterial safety and efficacy evaluations from one health perspective. We also highlight the directions for developing appropriate techniques to safely adopt magnetic and organic nanoparticles, and carbon nanosystems. A description was given of the specifics of targeting and treatment, especially for health purposes. Finally, we discuss C. elegans potential for studying the impacts caused by nanopesticides and nanoplastics as emerging contaminants, pointing out gaps in environmental studies related to toxicity, analytical methods, and future directions.

Towards novel nano-based vaccine platforms for SARS-CoV-2 and its variants of concern: Advances, challenges and limitations

Vaccination is the most effective tool available for fighting the spread of COVID-19. Recently, emerging variants of SARS-CoV-2 have led to growing concerns about increased transmissibility and decreased vaccine effectiveness. Currently, many vaccines are approved for emergency use and more are under development. This review highlights the ongoing advances in the design and development of different nano-based vaccine platforms. The challenges, limitations, and ethical consideration imposed by these nanocarriers are also discussed. Further, the effectiveness of the leading vaccine candidates against all SARS-CoV-2 variants of concern are highlighted. The review also focuses on the possibility of using an alternative non-invasive routes of vaccine administration using micro and nanotechnologies to enhance vaccination compliance and coverage.

Production of Minor Ginsenoside CK from Major Ginsenosides by Biotransformation and Its Advances in Targeted Delivery to Tumor Tissues Using Nanoformulations

For over 2000 years, ginseng (roots of Panax ginseng C.A. Meyer) has been used as a traditional herbal medicine. Ginsenosides are bioactive compounds present in ginseng responsible for the pharmacological effects and curing various acute diseases as well as chronic diseases including cardiovascular disease, cancer and diabetes. Structurally, ginsenosides consist of a hydrophobic aglycone moiety fused with one to four hydrophilic glycoside moieties. Based on the position of sugar units and their abundance, ginsenosides are classified into major and minor ginsenosides. Despite the great potential of ginsenosides, major ginsenosides are poorly absorbed in the blood circulation, resulting in poor bioavailability. Interestingly, owing to their small molecular weight, minor ginsenosides exhibit good permeability across cell membranes and bioavailability. However, extremely small quantities of minor ginsenosides extracted from ginseng plants cannot fulfill the requirement of scientific and clinical studies. Therefore, the production of minor ginsenosides in mass production is a topic of interest. In addition, their poor solubility and lack of targetability to tumor tissues limits their application in cancer therapy. In this review, various methods used for the transformation of major ginsenosides to minor ginsenoside compound K (CK) are summarized. For the production of CK, various transformation methods apply to major ginsenosides. The challenges present in these transformations and future research directions for producing bulk quantities of minor ginsenosides are discussed. Furthermore, attention is also paid to the utilization of nanoformulation technology to improve the bioavailability of minor ginsenoside CK.

Nanocarriers for Drug Delivery: An Overview with Emphasis on Vitamin D and K Transportation

Mounting evidence shows that supplementation with vitamin D and K or their analogs induces beneficial effects in various diseases, e.g., osteoarticular, cardiovascular, or carcinogenesis. The use of drugs delivery systems via organic and inorganic nanocarriers increases the bioavailability of vitamins and analogs, enhancing their cellular delivery and effects. The nanotechnology-based dietary supplements and drugs produced by the food and pharmaceutical industries overcome the issues associated with vitamin administration, such as stability, absorption or low bioavailability. Consequently, there is a continuous interest in optimizing the carriers' systems in order to make them more efficient and specific for the targeted tissue. In this pioneer review, we try to circumscribe the most relevant aspects related to nanocarriers for drug delivery, compare different types of nanoparticles for vitamin D and K transportation, and critically address their benefits and disadvantages.

A Revolutionary Blueprint for Mitigation of Hypertension via Nanoemulsion

Hypertension is one of the most important causes of mortality, affecting the health status of the patient. At the same time, hypertension causes a huge health and economic burden on the whole world. The incidence and prevalence of hypertension are rising even among young people in both urban as well as rural communities. Although various conventional therapeutic moieties are available for the management of hypertension, they have serious flaws such as hepatic metabolism, reduced dose frequency, poor aqueous solubility, reduced bioavailability, and increased adverse effects, making the drug therapy ineffective. Therefore, it is required to design a novel drug delivery system having the capability to solve the constraints associated with conventional treatment of hypertension. Nanotechnology is a new way of using and manipulating the matter at the molecular level, whose functional organization is measured in nanometers. The applications of nanotechnology in the field of medicine provide an alternative and novel direction for the treatment of cardiovascular diseases and show excellent performance in the field of targeted drug therapy. Various nanotechnologies based drug delivery systems, such as solid lipid nanoparticles, nanosuspension, nanoemulsion, liposome, self-emulsifying systems, and polymeric nanoparticles, are available. Among them, nanoemulsion has provided a niche to supplement currently available therapeutic choices due to numerous benefits like stability, ease of preparation, enhanced drug absorption, reduced hepatic metabolism, increased dose frequency, enhanced bioavailability, and encapsulation of hydrophilic as well as hydrophobic drugs. This present review provides an in-depth idea about progression in treatment of hypertension, constraints for antihypertensive drug therapy, need of nanoemulsions to overcome these constraints, comparative analysis of nanoemulsions over other nanostructure drug delivery systems, pharmacodynamics studies of nanoemulsions for treatment of hypertension, recent patents for drug-loaded nanoemulsions meant for hypertension, and marketed formulations of nanoemulsions for hypertension.

Amelioration of oxidative stress utilizing nanoemulsion loaded with bromocriptine and glutathione for the management of Parkinson's disease

Parkinson's disease (PD) is triggered by the formation of free radicals in dopaminergic neurons, which results in oxidative stress-induced neurodegeneration. The objective of the work was to relieve oxidative stress by employing intranasal delivery of Bromocriptine Mesylate (BRM) and Glutathione (GSH) loaded nanoemulsion for the better management of PD. The depth of permeation of the nanoemulsion was assessed through confocal laser scanning microscopy (CLSM) which revealed higher nanoemulsion permeation in contrast to suspension. Biocompatibility of nanoemulsion was confirmed by nasal cilio toxicity study. The DPPH study showed that the nanoemulsion had significant antioxidant activity. Biochemical estimation studies in Wistar rats were carried out in order to determine the effect of nanoemulsion on oxidative stress. The levels of GSH, superoxide dismutase (SOD), and catalase (CAT) were significantly enhanced; and the level of thiobarbituric acid reactive substances (TBARS) was significantly reduced after the intranasal administration of nanoemulsion in the haloperidol-induced model of PD. Furthermore, the levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were also determined which reduced significantly after the administration of nanoemulsion. The oxidative stress levels were lowered with nanoemulsion, showing the combined antioxidant capability of BRM and GSH. The neuroprotective effect of the prepared nanoemulsion was confirmed by histopathological studies. Pharmacokinetic study revealed a higher concentration of BRM and GSH in the brain of Wistar rats after intranasal administration of nanoemulsion with a higher Brain/Plasma ratio. A higher value of AUC_(0-8) of nanoemulsion in the brain after intranasal administration revealed that BRM and GSH remained in the brain for a longer period due to sustained release from nanoemulsion. According to the findings, BRM and GSH loaded nanoemulsion has the potential to provide a combined and synergistic anti-oxidant effect for efficient management of PD.

The Importance of Nanocarrier Design and Composition for an Efficient Nanoparticle-Mediated Transdermal Vaccination

The World Health Organization estimates that the pandemic caused by the SARS-CoV-2 virus claimed more than 3 million lives in 2020 alone. This situation has highlighted the importance of vaccination programs and the urgency of working on new technologies that allow an efficient, safe, and effective immunization. From this perspective, nanomedicine has provided novel tools for the design of the new generation of vaccines. Among the challenges of the new vaccine generations is the search for alternative routes of antigen delivery due to costs, risks, need for trained personnel, and low acceptance in the population associated with the parenteral route. Along these lines, transdermal immunization has been raised as a promising alternative for antigen delivery and vaccination based on a large absorption surface and an abundance of immune system cells. These features contribute to a high barrier capacity and high immunological efficiency for transdermal immunization. However, the stratum corneum barrier constitutes a significant challenge for generating new pharmaceutical forms for transdermal antigen delivery. This review addresses the biological bases for transdermal immunomodulation and the technological advances in the field of nanomedicine, from the passage of antigens facilitated by devices to cross the stratum corneum, to the design of nanosystems, with an emphasis on the importance of design and composition towards the new generation of needle-free nanometric transdermal systems.