The PEP++ study protocol: a cluster-randomised controlled trial on the effectiveness of an enhanced regimen of post-exposure prophylaxis for close contacts of persons affected by leprosy to prevent disease transmission.

BACKGROUND: Leprosy is an infectious disease with a slow decline in global annual caseload in the past two decades. Active case finding and post-exposure prophylaxis (PEP) with a single dose of rifampicin (SDR) are recommended by the World Health Organization as measures for leprosy elimination. However, more potent PEP regimens are needed to increase the effect in groups highest at risk (i.e., household members and blood relatives, especially of multibacillary patients). The PEP++ trial will assess the effectiveness of an enhanced preventive regimen against leprosy in high-endemic districts in India, Brazil, Bangladesh, and Nepal compared with SDR-PEP. METHODS: The PEP++ study is a cluster-randomised controlled trial in selected districts of India, Brazil, Bangladesh, and Nepal. Sub-districts will be allocated randomly to the intervention and control arms. Leprosy patients detected from 2015 - 22 living in the districts will be approached to list their close contacts for enrolment in the study. All consenting participants will be screened for signs and symptoms of leprosy and tuberculosis (TB). In the intervention arm, eligible contacts receive the enhanced PEP++ regimen with three doses of rifampicin (150 - 600 mg) and clarithromycin (150 - 500 mg) administered at four-weekly intervals, whereas those in the control arm receive SDR-PEP. Follow-up screening for leprosy will be done for each individual two years after the final dose is administered. Cox' proportion hazards analysis and Poisson regression will be used to compare the incidence rate ratios between the intervention and control areas as the primary study outcome. DISCUSSION: Past studies have shown that the level of SDR-PEP effectiveness is not uniform across contexts or in relation to leprosy patients. To address this, a number of recent trials are seeking to strengthen PEP regimens either through the use of new medications or by increasing the dosage of the existing ones. However, few studies focus on the impact of multiple doses of chemoprophylaxis using a combination of antibiotics. The PEP++ trial will investigate effectiveness of both an enhanced regimen and use geospatial analysis for PEP administration in the study communities. TRIAL REGISTRATION: NL7022 on the Dutch Trial Register on April 12, 2018. Protocol version 9.0 updated on 18 August 2022 https://www.onderzoekmetmensen.nl/en/trial/23060.

Hyphenation of lipophilic ruthenium(II)-diphosphine core with 5-fluorouracil: an effective metallodrug against glioblastoma brain cancer cells.

Glioblastoma multiforme (GBM) is the most common highly aggressive malignant brain tumor, with a very limited chance for survival post-diagnosis and post-treatment. Despite significant advancement in GBM genomics implicated in molecularly targeted chemotherapies, the prognosis remains poor and requires new drug discovery approaches. We used fluoropyrimidine 5-fluorouracil (5-FU), an antimetabolite anticancer drug conjugated or 'caged' within a lipophilic Ru(II)-diphosphine (dppe) core formulated as [RuII(dppe)2(5-FU)]PF6 (Ru-DPPE-5FU), where dppe = 1,2-bis(diphenylphosphino)ethane, and evaluated its in vitro cytotoxicity in depth with aggressive GBM cells (LN229). The hydrophilic nature of 5-FU limits its passage through the blood-brain barrier (BBB), which prevents its effective accumulation and efficacy for GBM tumors. Herein, we attempted to modulate the lipophilicity of 5-FU by inserting it within a well-designed lipophilic {Ru(dppe)2}-core with anticipated higher efficiency towards GBM. The physicochemical properties of [RuII(dppe)2(5-FU)]PF6 (Ru-DPPE-5FU) were studied using various spectroscopic and analytical techniques. The molecular structure was determined using X-ray crystallography, showing a distorted {RuP4NO} octahedral geometry with bidentate (N, O) binding of 5-FU and its aromatization in the Ru(II)-bound form. The 31P-NMR spectra of Ru-DPPE-5FU showed four closely spaced distinct 31P-signals, indicating four unique chemical environments around P, and the strong coupling constants between them make it a second-order spectrum. The RuII/RuIII redox potential in Ru-DPPE-5FU shifted by ∼0.91 V towards the anodic region as compared to its precursor complex cis-[Ru(dppe)2Cl2] (Ru-DPPE-Cl). DFT-based theoretical calculations have been performed to correlate the experimental electronic absorption spectra and redox behaviours of the complexes. The electrostatic potential (ESP) plots indicate the delocalization of the charge density on the O-/F-atom from the 5-FU ligand towards Ru(II) upon its complexation. The antioxidant properties of all the compounds were quantified by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The hyphenation of the 5-fluorouracil (5-FU) ligand to the lipophilic {Ru(dppe)2}-core endowed lipophilicity to Ru-DPPE-5FU with higher in vitro cytotoxicity (IC50 = 2.37 µM) against the LN229 GBM cells as compared to the hydrophilic 5-FU, suggesting efficient cellular uptake. Further biological assays indicated that the complex is highly potent in inhibiting significant proliferation and spheroid formation and restricting the migratory potentials of the GBM cells. Increased caspase 3/7 activity and the presence of apoptotic bodies at the center of 3-D GBM spheroids as revealed by AO/EB dual staining indicated a deeper penetration of the lipophilic complex. The Ru-DPPE-5FU complex displayed lower cytotoxicity in HaCaT normal cells (IC50 = 7.27 µM) in comparison to LN229 cancer cells with a selectivity index (S.I.) of ≥3. Overall, the synergism and caging of 5-FU within the hydrophobic {Ru(dppe)2}-core improves the pharmacokinetic profile of Ru-DPPE-5FU as a potent anticancer agent for glioblastoma.

Total Reflection X-ray Fluorescence Spectrometric Analysis of Ten Lanthanides at the Ultratrace Level Having a High Degree of Overlap in the Emission Lines.

The extensive use of lanthanide elements in the medical, electrical, agricultural, and nuclear fields has increased their contamination in the environment. The detrimental effect of lanthanides on human health can be reduced or eliminated by their fast determination in the concerned specimen. For this purpose, an offline conjugation of the cloud point extraction (CPE) process with total reflection X-ray fluorescence (TXRF) spectrometry was done. This process was found to provide simple, quick, and precise simultaneous determination of ten lanthanides whose emission lines have a high degree of overlap at the ultratrace level. N,N,N',N'-tetra-octyl-diglycolamide in triton X-114 micelles was found to offer a selective CPE of all of the lanthanides in the presence of higher concentrations of naturally abundant cations and anions. A multivariative partial least-squares regression (PLSR) calibration approach was preferred due to the complex overlapped spectra of L lines of the lanthanides. Ten lanthanides, viz., La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, and Lu, were simultaneously determined by this method, having concentrations in the range from 10 to 5 × 103 µg L-1. The proposed method was validated by analyzing three certified reference materials (CRMs), viz., NASS-7 seawater, SRLS-6 river water, and NIST 1640a natural water, via standard addition with the relative standard deviations of ≤10%.

Liposomes Containing Zinc-Based Chemotherapeutic Drug Block Proliferation and Trigger Apoptosis in Breast Cancer Cells.

Platinum-based chemotherapeutic drugs are effective in killing malignant cells but often trigger drug resistance or off-target side effects. Unlike platinum, zinc is used as an endogenous cofactor for several cellular enzymes and may, thus, display increased biocompatibility. In this present study, we have rationally designed and synthesized two substituted phenanthro[9,10-d]imidazole-based ligands L1 and L2 with pyridine and quinoline substitution at the 2 position and their corresponding Zn(II) complexes; (L1)2Zn and (L2)2Zn, which are characterized by standard analytical and spectroscopic methods. (L2)2Zn, but not (L1)2Zn has intrinsic fluorescence, indicating its potential utility in imaging applications. To facilitate cellular uptake, we generated liposomal formations with a phospholipid DMPC (1,2-Dimyristoyl-sn-glycero-3-phosphocholine) through molecular self-assembly. These liposomal formulations Lip-(L1)2Zn and Lip-(L2)2Zn were able to enter breast cancer cells, induce DNA fragmentation, arrest the cell cycle at the G0/G1 phase, decrease proliferation, and promote apoptosis by activating the DNA damage response. Importantly, both Lip-(L1)2Zn and Lip-(L2)2Zn decreased the size of breast cancer cell-based spheroids, indicating they may be capable of suppressing tumor growth. Our work represents an important proof-of-concept exercise demonstrating that successful liposomal formation of phenanthro[9,10-d]imidazole-based Zn(II) complexes with inherent optical properties have great promise for the development of imaging probes and efficient anticancer drugs.

Ruthenium(II) Polypyridyl-Based Photocages for an Anticancer Phytochemical Diallyl Sulfide: Comparative Dark and Photoreactivity Studies of Caged and Precursor Uncaged Complexes.

The spatiotemporal control over the drug's action offered by ruthenium(II) polypyridyl complexes by the selective activation of the prodrug inside the tumor has beaconed toward much-desired selectivity issues in cancer chemotherapy. The photocaging of anticancer bioactive ligands attached synergistically with cytotoxic Ru(II) polypyridyl cores and selective release thereof in cancer cells are a promising modality for more effective drug action. Diallyl sulfide (DAS) naturally found in garlic has anticancer, antioxidant, and anti-inflammatory activities. Herein, we designed two Ru(II) polypyridyl complexes to cage DAS having a thioether-based donor site. For in-depth photocaging studies, we compared the reactivity of the DAS-caged compounds with the uncaged Ru(II)-complexes with the general formula [Ru(ttp)(NN)(L)]+/2+. Here, in the first series, ttp = p-tolyl terpyridine, NN = phen (1,10-phenanthroline), and L = Cl- (1-Cl) and H2O (1-H2O), while for the second series, NN = dpq (pyrazino[2,3-f][1,10]phenanthroline), and L = Cl- (2-Cl) and H2O (2-H2O). The reaction of DAS with 1-H2O and 2-H2O yielded the caged complexes [Ru(ttp)(NN)(DAS)](PF6)2, i.e., 1-DAS and 2-DAS, respectively. The complexes were structurally characterized by X-ray crystallography, and the solution-state characterization was done by 1H NMR and ESI-MS studies. Photoinduced release of DAS from the Ru(II) core was monitored by 1H NMR and UV-vis spectroscopy. When irradiated with a 470 nm blue LED in DMSO, the photosubstitution quantum yields (Φ) of 0.035 and 0.057 were observed for 1-DAS and 2-DAS, respectively. Intriguing solution-state speciation and kinetic behaviors of the uncaged and caged Ru(II)-complexes emerged from 1H NMR studies in the dark, and they are depicted in this work. The caged 1-DAS and 2-DAS complexes remained mostly structurally intact for a reasonably long period in DMSO. The uncaged 1-Cl and 2-Cl complexes, although did not undergo substitution in only DMSO but in the 10% DMSO/H2O mixture, completely converted to the corresponding DMSO-adduct within 16 h. Toward gaining insights into the reactivity with the biological targets, we observed that 1-Cl upon hydrolysis formed an adduct with 5'-GMP, while a small amount of GSSG-adduct was observed when 1-Cl was reacted with GSH in H2O at 323 K. 1-Cl after hydrolysis reacted with l-methionine, although the rate was slightly slower compared with that with DMSO, suggesting varying reaction kinetics with different sulfur-based linkages. Although 1-H2O reacted with sulfoxide and thioether ligands at room temperature, the rate was much faster at higher temperatures obviously, and thiol-based systems needed higher thermal energy for conjugation. Overall, these studies provide insight for thoughtful design of new generation Ru(II) polypyridyl complexes for caging suitable bioactive organic molecules.

Co-Existence of Nodular Purpura and Vaccine Induced Panniculitis in a 4-Month-Old Baby-A Diagnostic Dilemma.

Vitamin K deficient bleeding (VKDB) disorder is a rare but fatal disorder that needs prompt diagnosis and timely intervention. Among its varied clinical manifestations, nodular purpura is rare one. Proper knowledge of this presentation helps clinicians to exclude other close differentials and avoid unnecessary delays in diagnosis. Though bleeding from the vaccination site could be a manifestation of VKDB, the concomitant presence of nodular purpura and vaccine-induced panniculitis in the same patient is rare. We report a case of a 4-month-old baby presenting with both, posing a diagnostic dilemma.

Selective Extraction of Thorium(IV) from Uranium and Rare Earth Elements Using Tetraphenylethane-1,2-diylbis(phosphoramidate).

Tetraphenylethane-1,2-diylbis(phosphoramidate) in conjugation with a room temperature ionic liquid in chloroform medium is reported for the first time in the liquid-liquid extraction of thorium (Th). The extracted Th(IV) is collected as a white solid in the organic medium, thereby facilitating its easy separation. A high distribution ratio (D) of (12.4 ± 0.1) × 103 in 2-8 mol L-1 acidity range and high decontamination factors (α) of Th(IV) from uranium, lanthanides, and a number of transition elements makes this extraction process versatile and selective. A number of experimental investigations in synergism with extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) studies are interpreted to confirm the structure of the chelated complex. A 1:2 metal/ligand complex in which the two oxygen and two nitrogen atoms of each bis(phosphoramidate) molecule satisfying the eight coordination sites of Th(IV) is found to be formed. The extracted white solid thorium complex is easily converted to ThO2 after washing and heating at 1300 °C under O2 atmosphere. This work is expected to find direct application in the thorium fuel cycle, especially in the mining process of thorium from its ores and in the separation of fissile 233U from fertile 232Th in irradiated fuel.

Filaggrin gene polymorphisms in Indian children with atopic dermatitis: A cross-sectional multicentre study.

Background Filaggrin (FLG) gene encoding the protein filaggrin plays an important role in barrier function of the skin and its alteration is a predisposing factor for atopic dermatitis. FLG gene variants result in absent or decreased filaggrin protein. Worldwide, the prevalence of FLG variants ranges from 14 to 56%. FLG null variants are distinct in each population. Objectives To study the FLG gene polymorphisms in Indian children and attempt a genotype-phenotype correlation in atopic dermatitis. Methods This was a cross-sectional, multicentre study conducted on 75 Indian children. Demographic details, clinical features and identified FLG null variants were recorded. We performed a whole gene sequencing of the entire FLG coding region using next-generation sequencing technology. Results The prevalence of FLG null variants was 34.7%. A total of 20 different FLG loss of function variants in 26 children were documented. Sixteen (80%) variants were novel and four (20%) were previously reported in Asian and European populations. We found a statistically significant association between FLG variants with early age of onset of atopic dermatitis (P = 0.016) and elevated serum IgE levels (P = 0.051). There was no significant difference between atopic dermatitis phenotypes in children having one variant as compared to children harbouring two or more null variants. Limitation Small sample size. Conclusion Our study reports a unique set of FLG variants different from Asian and European populations, with these variants being significantly associated with an early age of onset of atopic dermatitis and elevated serum IgE levels.

An extended DNMA-based multi-criteria decision-making method and its application in the assessment of sustainable location for a lithium-ion batteries' manufacturing plant.

Lithium-ion battery (LiB), a leading residual energy resource for electric vehicles (EVs), involves a market presenting exponential growth with increasing global impetus towards electric mobility. To promote the sustainability perspective of the EVs industry, this paper introduces a hybridized decision support system to select the suitable location for a LiB manufacturing plant. In this study, single-valued neutrosophic sets (SVNSs) are considered to diminish the vagueness in decision-making opinions and evade flawed plant location assessments. This study divided into four phases. First, to combine the single-valued neutrosophic information, some Archimedean-Dombi operators are developed with their outstanding characteristics. Second, an innovative utilization of the Method based on the Removal Effects of Criteria (MEREC) and Stepwise Weight Assessment Ratio Analysis (SWARA) is discussed to obtain objective, subjective and integrated weights of criteria assessment with the least subjectivity and biasedness. Third, the Double Normalization-based Multi-Aggregation (DNMA) method is developed to prioritize the location options. Fourth, an illustrative study offers decision-making strategies for choosing a suitable location for a LiB manufacturing plant in a real-world setting. Our outcomes specify that Bangalore (L 2), with an overall utility degree (0.7579), is the best plant location for LiB manufacturing. The consistency and robustness of the presented methodology are discussed with the comparative study and sensitivity investigation. This is the first study in the current literature that has proposed an integrated methodology on SVNSs to select the best LiB manufacturing plant location by estimating both the objective and subjective weights of criteria and by considering ambiguous, inconsistent, and inexact manufacturing-based information.

PSS functionalized and stabilized carbon nanodots for specific sensing of iron in biological medium.

Carbon Quantum Dots (CQDs) are already emerged as an excellent sensing element for its exceptional behavior in fluorescence, biocompatibility, and water dispersibility. However, its poor stability, selectivity and reproducibility in complex medium still be a big problem for its practical application. To overcome this, in the work, we have developed a new type of carbon quantum dot-PSS fluorescent nanocomposites which has been used for specific Fe3+ detection. The polystyrene sulfonate (PSS) polymer not only stabilize the QDs but also produces specific sites for Fe3+ to make a co-ordinate complex via Fe3+-SO3. The detection limit is calculated as low as 1 ppm which is adequate for measuring Fe3+ in blood or water samples. The mechanism of the quenching is very specific towards the Fe3+ ion due to the presence of PSS which makes the sensor selective among other metal ions and possible interferences. The rapid process of sensing, simple instrumentation, and excellent performances in presence of 1 % BSA and serum samples indicates the possible application for diagnostic usage in near future.

Vanillin Benzothiazole Derivative Reduces Cellular Reactive Oxygen Species and Detects Amyloid Fibrillar Aggregates in Alzheimer's Disease Brain.

The misfolding of amyloid beta (Aß) peptides into Aß fibrillary aggregates is a major hallmark of Alzheimer's disease (AD), which responsible for the excess production of hydrogen peroxide (H2O2), a prominent reactive oxygen species (ROS) from the molecular oxygen (O2) by the reduction of the Aß-Cu(I) complex. The excessive production of H2O2 causes oxidative stress and inflammation in the AD brain. Here, we have designed and developed a dual functionalized molecule VBD by using π-conjugation (C═C) in the backbone structure. In the presence of H2O2, the VBD can turn into fluorescent probe VBD-1 by cleaving of the selective boronate ester group. The fluorescent probe VBD-1 can undergo intramolecular charge transfer transition (ICT) by a π-conjugative system, and as a result, its emission increases from the yellow (532 nm) to red (590 nm) region. The fluorescence intensity of VBD-1 increases by 3.5-fold upon binding with Aß fibrillary aggregates with a high affinity (Kd = 143 ± 12 nM). Finally, the VBD reduces the cellular toxic H2O2 as proven by the CCA assay and DCFDA assay and the binding affinity of VBD-1 was confirmed by using in vitro histological staining in 8- and 18-month-old triple transgenic AD (3xTg-AD) mice brain slices.

Entropy and discrimination measures based q-rung orthopair fuzzy MULTIMOORA framework for selecting solid waste disposal method.

Fastest growing population, rapid urbanization, and growth in the disciplines of science and technology cause continually development in the amount and diversity of solid waste. In modern world, evaluation of an appropriate solid waste disposal method (SWDM) can be referred as multi-criteria decision-making (MCDM) problem due to involvement of several conflicting quantitative and qualitative sustainability indicators. The imprecision and ambiguity are usually arisen in SWDM assessment problem, and the q-rung orthopair fuzzy set (q-ROFS) has been recognized as one of the adaptable and valuable ways to tackle the complex uncertain information arisen in realistic problems. In the context of q-ROFSs, entropy is a significant measure for depicting fuzziness and uncertain information of q-ROFS and the discrimination measure is generally used to quantify the distance between two q-ROFSs by evaluating the amount of their discrimination. Thus, the aim of this study is to propose a novel integrated framework based on multi-attribute multi-objective optimization with the ratio analysis (MULTIMOORA) method with q-rung orthopair fuzzy information (q-ROFI). In this approach, an integrated weighting process is presented by combining objective and subjective weights of criteria with q-ROFI. Inspired by the q-rung orthopair fuzzy entropy and discrimination measure, objective weights of criteria are estimated by entropy and discrimination measure-based model. Whereas, the subjective weights are derived based on aggregation operator and the score function under q-ROFS environment. In this respect, novel entropy and discrimination measure are proposed for q-ROFSs. Furthermore, to display the feasibility and usefulness of the introduced approach, a case study related to SWD method selection is presented under q-ROFS perspective. Finally, comparison and sensitivity investigation are presented to confirm the robustness and solidity of the introduced approach.

Intermittent or Sequential Topical Tacrolimus in Atopic Dermatitis: Systematic Review and Meta-Analysis.

Topical calcineurin inhibitors (TCIs) and topical corticosteroids (TCS) are the mainstays of flare management for atopic eczema or atopic dermatitis (AD). Tacrolimus (an immunomodulator), belongs to the class of calcineurin inhibitors, with promising efficacy in AD. We performed this systematic review to obtain an up-to-date coverage map of controlled clinical trials of sequential or intermittent treatments with TCI as a therapeutic intervention for AD. Articles of interest were retrieved from PubMed, Google Scholar, and EMBASE published between between January 2000 and March 2023. Key words were "calcineurin inhibitors," "corticosteroids," "atopic dermatitis," "pruritus," "sequential," "intermittent" and "consecutive" while fixed language search consisted of "Intermittent topical calcineurin inhibitors AND topical corticosteroids AND atopic dermatitis OR eczema" AD patients who were administered sequential and/or intermittent applications of TCI for management of atopic eczema were included. Outcome measures included but were not limited to Scoring of Atopic Dermatitis (SCORAD) and the Eczema Area Severity Score (EASI). Four clinical trials were considered for the purpose of review. A total of 101 patients with AD were analysed. The risk of bias was low in two studies, while the other two had an unclear risk of bias. Overall, pooled data from two trials revealed that sequential therapy with TCS/TCI was comparable to monotherapy or emollients, as the test for overall effect determined was non-significant with a p-value of 0.33. The two studies were highly heterogeneous, as indicated by a very high I2 of 92% and an extremely significant p-value (p=0.0005). Sequential therapy with TCS and TCIs was effective and well tolerated in the management of AD and it may be considered an important treatment approach during the initial period.

A Simplified Approach for the Aqueous Synthesis of Luminescent CdSe/ZnS Core/Shell Quantum Dots and Their Applications in Ultrasensitive Determination of the Biomarker 3-Nitro-l-tyrosine.

In contrast to the hot-injection organometallic routes, synthesizing stable and highly luminescent core/shell nanocrystals with encapsulation of biocompatible groups through an aqueous route is a long-standing challenge. In recent years, relatively high quantum efficiency and unique properties of core/shell nanostructured materials (quantum dots) have contributed toward enhancement in sensing capability. The present work reports a facile aqueous synthesis process of core/shell CdSe/ZnS quantum dots (QDs) with encapsulation of glutathione (GSH). The optimal conditions for the synthesis of the most stable particles were ascertained, and the different experimental analyses suggest that the stable core/shell QDs in question have good crystallinity with a size around 4.7 nm with a shell thickness of 0.7 nm and a photoluminescence quantum yield of about 35%. Further, it is demonstrated that the as-synthesized material has great potential in detecting as low as 0.28 nM 3-nitro-l-tyrosine (3-NT), an important marker for oxidative stress, the level of which in our body signals several chronically diseased conditions. The enthalpy-driven interactions of CdSe/ZnS-GSH QDs with 3-NT were characterized through steady-state and time-resolved luminescence spectroscopy and isothermal microcalorimetry. The devised method of probing 3-NT was further validated with human serum samples. Thus, the proposed strategy may provide a protocol for selective determination of 3-NT under different pathological conditions.

Multiple attribute decision making based on Pythagorean fuzzy Aczel-Alsina average aggregation operators.

A useful expansion of the intuitionistic fuzzy set (IFS) for dealing with ambiguities in information is the Pythagorean fuzzy set (PFS), which is one of the most frequently used fuzzy sets in data science. Due to these circumstances, the Aczel-Alsina operations are used in this study to formulate several Pythagorean fuzzy (PF) Aczel-Alsina aggregation operators, which include the PF Aczel-Alsina weighted average (PFAAWA) operator, PF Aczel-Alsina order weighted average (PFAAOWA) operator, and PF Aczel-Alsina hybrid average (PFAAHA) operator. The distinguishing characteristics of these potential operators are studied in detail. The primary advantage of using an advanced operator is that it provides decision-makers with a more comprehensive understanding of the situation. If we compare the results of this study to those of prior strategies, we can see that the approach proposed in this study is more thorough, more precise, and more concrete. As a result, this technique makes a significant contribution to the solution of real-world problems. Eventually, the suggested operator is put into practise in order to overcome the issues related to multi-attribute decision-making under the PF data environment. A numerical example has been used to show that the suggested method is valid, useful, and effective.

Platform for Active Vaccine Formulation Using a Two-Mode Enhancement Mechanism of Epitope Presentation by Pickering Emulsion.

The efficiency of epitope-based vaccination (subunit vaccines) is tightly correlated with heterogeneity and the high density of epitope presentation, which maximizes the potential antigenic determinants. Here, we developed a two-mode platform for intensifying the epitope presentation of subunit vaccines. The two-mode epitope presentation enhancement includes a covalent attachment of high concentrations of SARS-CoV-2-S1 peptide epitope to the surface of virus-like-particles (VLPs) and the subsequent assembly of VLP/epitope conjugates on the oil droplet surface at an oil/water interface of an emulsion as Pickering stabilizers. The resultant emulsions were stable for weeks in ambient conditions, and our platform was challenged using the epitope of the SARS-CoV-2-S1 peptide that served as a model epitope in this study. In vivo assays showed that the αSARS-CoV-2-S1 immunoglobulin G (IgG) titers of the studied mouse antisera, developed against the SARS-CoV-2-S1 peptide under different epitope preparation conditions, showed an order of magnitude higher IgG titers in the studied VLP-based emulsions than epitopes dissolved in water and epitopes administered with an adjuvant, thereby confirming the efficacy of the formulation. This VLP-based Pickering emulsion platform is a fully synthetic approach that can be readily applied for vaccine development to a wide range of pathogens.