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HfO2can assume different crystalline structures, such as monoclinic, orthorhombic, and cubic polymorphs, each one characterized by unical properties. The peculiarities of this material are also strongly related to the presence of doping elements in the unit cell. Thus, the present paper has the main purpose of studying and comparing twelve different systems characterized by diverse polymorphs and doping percentages. In particular, three different crystalline structures were considered: the monoclinicP21/c, the orthorhombicPca21, and the cubicFm3̲3¯mphases of HfO2. Each one has been studied by using Y as a doping agent with three different contents: 0% Y:HfO2, 8% Y:HfO2, 12% Y:HfO2, and 16% Y:HfO2. For all the systems, density functional theory (DFT) methods based on PBE/GGA, and on the HSE hybrid functionals were used to optimize the geometry as well as to study their optical properties. Depending on the polymorphs, Y affects the formation energy in different ways and causes changes in the optical properties. When the percentage of Y did not exceed 12%, a stabilization of the cubic phase fraction and an increase of the dielectric constant was observed. Additionally, the calculated optical bandgap energies and the refractive index are examined to provide an overview of the systems and are compared with experimental data. The bandgaps obtained are in perfect agreement with the experimental values and show a slight increase as the doping percentage grows, while only minor differences are found between the three polymorphs in terms of both refractive index and optical band gap. The adopted first principles study generates a reasonable prediction of the physical-chemical properties of all the systems, thus identifying the effects of doping phenomena.

We have studied the structural, electronic, magnetic, and optical properties of the VO2(B) polymorph using first-principles calculations based on density functional theory (DFT). This polymorph was found to display four optimized structures namely VO2(B)PP, VO2(B)LP, VO2(B)PPD, and VO2(B)LPDusing the generalized gradient approximation (GGA) PBE exchange-correlation functional by including/excluding van der Waals interaction. Our derivation provides a theoretical justification for adding an on-site CoulombUvalue in the conventional DFT calculations to allow a direct comparison of the two methods. We predicted a zero bandgap of the VO2(B) structure based on GGA/PBE. However, by GGA/PBE + U, we found accurate bandgap values of 0.76, 0.66, and 0.70 eV for VO2(B)PP, VO2(B)LP, and VO2(B)PPD, respectively. The results obtained from DFT + U were accompanied by a structural transition from the metallic to semiconductor property. Here, we verified the non-magnetic characteristic of the monoclinic VO2(B) phase with some available experimental and theoretical data. However, the debate on the magnetic property of this polymorph remains unresolved. Imaginary and real parts of the dielectric function, as computed with the GGA/PBE functional and the GGA/PBE + U functional, were also reported. The first absorption peaks of all considered geometries in the imaginary part of the dielectric constants indicated that the VO2(B) structure could perfectly absorb infrared light. The computed static dielectric constants with positive values, as derived from the optical properties, confirmed the conductivity of this material. Among the four proposed geometries of VO2(B) in this study, the outcomes obtained by VO2(B)PPDreveal good results owing to the excellent consistency of its bandgap, magnetic and optical properties with other experimental and theoretical observations. The theoretical framework in our study will provide useful insight for future practical applications of the VO2(B) polymorph in electronics and optoelectronics.

This work aimed to precisely evaluate the physical properties of vanadium dioxide (M), particularly the optical characteristics. We employed different exchange-correlation functionals to determine the phase stability, band gap properties, and optical characteristics of an experimentally recognized monoclinic VO2(M) polymorph. The calculations not only correctly interpreted the VO2(M) origin but also predicted other optical properties including the extinction coefficient (k�) and refractive index (n�), which have not been reported in experimental measurements. Phonon dispersion calculations confirmed the presence of negative frequencies for acoustic modes in the phononic curves. When the HSE functional correctly reproduced the experimental band gap, here for the first time, our calculations based on PBE and PBEsol yielded non-zero electronic bandgaps of 0.23 and 0.15eV for bulk VO2(M). Our predictions showed that semi-local functionals can adequately predict the semiconductor properties of VO2(M) and performed better than all previously reported theoretical works on nulled band gaps. In addition to the better prediction of the peak position in the absorption spectra with HSE hybrid functional, this method also reasonably well described the static dielectric constant of 7.54, showing an excellent match to the experimental values. In general, the results of this study reveal that hybrid functionals yield superior outcomes compared to semi-local functionals for optical properties of a VO2(M) polymorph. Our results suggest that the PBEsol + HSE approach allows the efficient characterization of smart materials for electronic and optoelectronic applications.

I sedimenti rappresentano la principale sede di accumulo di specie chimiche organiche ed inorganiche veicolate dalle acque fluviali alle aree marino-costiere. Svariati sono gli studi incentrati sulla geochimica dei sedimenti in termini di presenza, distribuzione e mobilità di contaminanti organici ed elementi in tracce potenzialmente tossici (Covelli et al., 2001). Tuttavia, poche sono le informazioni ad oggi esistenti relativamente a quelli che vengono definiti contaminanti emergenti, tra cui rientrano gli elementi delle Terre Rare (Rare Earth Elements, REE). Le REE comprendono 17 elementi metallici che includono l’intera serie dei lantanidi, unitamente allo scandio (Sc) e all’ittrio (Y) e vengono generalmente distinte in REE leggere e pesanti (LREE, HREE) in funzione del peso atomico. Nonostante siano definiti rari, questi elementi sono piuttosto diffusi nella crosta terrestre e ampiamente utilizzati in attività agricole, ospedaliere e in ambito industriale per la produzione di svariati dispositivi tecnologici di uso quotidiano. Per queste ragioni, la loro presenza in diverse matrici ambientali quali sedimenti, acque eparticellato in sospensione, è spesso oggetto di studio da parte della comunità scientifica internazionale. Infatti, le REE possono essere utilizzate come traccianti di fenomeni naturali, come processi erosivi, ma anche di attività antropiche (Viers et al., 2009; Piper and Bau, 2013; da Silva et al., 2018). Questo studio si pone come obiettivo una valutazione preliminare della presenza e distribuzione delle REE nei sedimenti superficiali dell’Alto Adriatico, rappresentativi di un’area compresa tra il Golfo di Trieste e il delta del fiume Po. Questi sedimenti sono stati oggetto di una precedente indagine sulla contaminazione da metalli pesanti e da idrocarburi nei sedimenti superficiali dei mari italiani (CoNISMa, 2001). Di conseguenza, il presente studio si propone di ampliare le informazioni già esistenti allo scopo ultimo di valutare l’origine di questi elementi unitamente alla presenza di eventuali anomalie nelle concentrazioni delle REE dovute a potenziali contributi antropici.

Human skin forms a unique interface between the body and the external environment. Its main role is to protect the internal organs from external factors. Notably, the outermost skin layer, stratum corneum, forms a remarkable barrier for permeation of xenobiotics in general, but unfortunately it may become an entry route of hazardous substances. Metals can penetrate and permeate the skin inducing local effects such as skin sensitization with allergic contact dermatitis and potential metals diffusion into the bloodstream with systemic intoxication[1] [2]. Metals in nano dimensions penetrate and permeate the skin in higher amount[3] [4] compared to bulk materials due to their smaller dimensions[5].Therefore, if the stratum corneum is damaged to various factors such as inflammation, desquamation, defects in lipid distribution or epidermal thickening, the transcutaneous passage of a molecule is expected to be drastically enhanced[6] [7]. In this study, we investigate the percutaneous penetration of metals from the road dust powder in intact as well damaged skin to mimic the effect of skin lesions. In addition, porcine and human skin were compared as skin models. The certified reference material BCR®-723 provided by the European Institute for Reference Materials and Measurements was used as road dust formulation. To evaluate the extent of ionization of metals from BCR®-723, the dissolution of powder in synthetic sweat solutions at two different pH (pH 4.5, 6.5) was carried out. Periodic quantification of metals concentration was monitored and analyzed via inductively coupled plasma - optical emission spectroscopy (ICP-OES). The choice of synthetic sweat solution at pH 4.5 was dictated to reproduce the workplace conditions. Dermal absorption from donor compartment containing metals was monitored for 24 hours. The amounts of metals retained in skin were quantified post-exposure by inductively coupled plasma - mass spectrometer (ICP-MS). Percutaneous absorption of lead (Pb) was higher in both intact skin models (549 ng/cm2 in porcine skin vs 68.80 ng/cm2 in human model). Moreover, cobalt (Co) accumulation was higher in porcine skin reaching a value of 518 ng/cm2 than those found in human skin (1.85 ng/cm2). In contrast with the observations reported in human skin model, chromium (Cr) achieved the lowest skin absorption in porcine model (183 ng/cm2). As expected, metals permeation on damaged skin was enhanced due to the removal of the barrier function. These consequence differences may be due to the skin tissues, but pig skin appeared as the most suitable replacement for human skin.

Sediments are considered reservoirs of contaminants, but they can also act as a secondary source of contamination since remobilisation processes at the sediment-water interface (SWI) may affect the water quality (Caplat et al., 2005; Petranich et al., 2018). The estuarine system of the Timavo River is located in the Gulf of Trieste (northern Adriatic Sea). The innermost sector of the estuary was recognised as the most critical area showing high concentrations of potentially toxic elements (PTEs) in sediments and scarce water circulation which led to a permanent oxic-hypoxic interface along the water column (Pavoni et al., 2020). Field activity was performed before (June) and after (September) the forced aeration of a system of porous pipes laid on the bottom aiming at re-oxygenating the water column in summer. Sampling was carried out along the water column, short sediment cores were collected to investigate both solid phase and porewaters and in situ benthic chamber experiments were conducted at the SWI. The primary aim of the work was to understand if and how biogeochemical processes may affect PTE (As, Cr, Hg, Fe, Mn, Ni, Pb, V) mobility and related fluxes at the SWI. The water column was found to be oxygen stratified and hypoxia occurred at the bottom, mostly in June (2.29 mg/L) when reductive conditions were also observed (-58 mV). As a result, dissolved PTEs increased with depth reaching maximum values at the bottom due to dissolution/desorption processes of Fe and Mn oxy-hydroxides (Dellwig et al., 2010). This evidence was confirmed by the benthic chamber experiments highlighting a gradual oxygen depletion inside the chamber due to organic matter remineralisation with subsequent increase of dissolved PTEs. The porewater profiles were found to be different between the two campaigns showing the highest PTE concentrations in June, mostly at the top of the sedimentary sequence suggesting that release of PTEs at the SWI is promoted in hypoxic conditions.

Decommissioned mines represent a worldwide concern for the environment even for decades to hundreds of years since the activities ceased, and also in those areas located at long distances from the mining sites. The most important mining district of the Friuli Venezia Giulia region is the Pb-Zn Raibl mine, sited in the NE sector of the Julian Alps, near the border with Austria and Slovenia. The mine had a secular history since the first evidence of mining activity is dated to 1320 whereas it closure is dated back to 1991. Only in the 1976-1991 period, almost 4 million tons of mine tailings, products from milling and enrichment (flotation) processes of sphalerite (ZnS) and galena (PbS), have been stored in a tailings impoundment nearby the main stream flowing the area, the Rio del Lago creek. The tailings contain very high concentrations of base metals (Zn, Pb and Fe) and potentially toxic trace elements (PTEs: As, Cd, Tl, Sb). The site is currently under remediation to mitigate the impact on the environment, however, since the availability of such elements in the stream waters represent a concern for the freshwater ecosystem, the water quality is constantly monitored. Ten years of groundwater monitoring results in several piezometers in the area conducted by ARPA FVG and the University of Trieste are presented. The time-series of the hydrochemistry evolution of tailings groundwaters has given the opportunity to observe the long- and short-term variations of elemental concentrations, thus suggesting the processes that lead the release of potential toxic elements (Tl, Zn and Pb) to groundwaters and some possible scenarios about future perspectives of contamination. The short-term hourly data from groundwaters, entrapped in the tailing ponds, indicate high frequency relationship between hydrology and oxidation of sulfides that release PTEs. On the contrary, long-term hydrochemical series indicate that groundwaters inside the ponds are generally depleting in dissolved metals, due to both remediation actions and chemical depletion of the source. Groundwaters undergo a progressive enrichment of the main PTE concentrations, although this enrichment is limited to a few hundreds of meters downstream the impoundment. Time-series analysis on the decay of PTEs performed with first-order rate constants (Newell et al., 2002), estimates that the dissolved metal contents in groundwater entrapped in the tailings could drop below the national law limits in a time interval from a couple of years to some decades. On the contrary, uncertain future scenarios about downstream enrichment have arisen.

Mercury (Hg) contamination in the Gulf of Trieste (GT, northern Adriatic Sea) is due to historical mining activity in Idrija (Slovenia) and still represents an environmental issue of great concern (Covelli et al., 2001; Covelli et al., 2021). Indeed, the freshwater inputs from the Isonzo/Soča River have been identified as the main source of Hg into the GT. At the river mouth, the element was found to be mainly associated with the suspended particulate matter, especially following periods of medium-high river discharge and river plume events in the GT (Covelli et al., 2006; 2007). The primary aim of this research is to evaluate the occurrence and distribution of both dissolved (DHg) and particulate (PHg) Hg along the water column in the northernmost sector of the GT, a shallow and sheltered embayment suitable for the accumulation of fine sediments and contaminants. In order to achieve this objective, sediment and water samples were collected at six sites which were representative of different targets, such as mussel farming and tourism activities. Moreover, different environmental conditions including unperturbed and perturbed hydrological conditions, induced by both natural and anthropogenic factors, were taken into account. The amount of Hg in the surface sediments (0.77–6.39 μg g-1) as well as the relationship between the Hg concentration and the percentage of the 2-16 μm grain size fraction from this study were found to be consistent with previous research focused on the whole Gulf, thus testifying the common origin of the sediment. Results showed a notable variability of DHg (0.07–149 ng L-1) and PHg (0.39–12.5 ng L-1) depending on the interaction between riverine and meteo-marine hydrological conditions at the time of sampling. Mercury was found to be mainly partitioned in the suspended particles and elevated values of PHg were observed following periods of high discharge from the Isonzo/Soča River confirming that the river discharge may represent an important factor in regulating the amount of PHg in the GT.

Sediments often act as reservoirs of contaminants, but they can also be considered a secondary source of contamination due to remobilisation processes at the sediment-water interface (SWI) which may affect the quality of the overlying water and aquatic biota [1,2]. The estuarine system of the Timavo/Reka River is located in the Gulf of Trieste (northern Adriatic Sea) and the innermost sector of the estuary was recognised as the most critical area. There, elevated concentrations of potentially toxic trace elements (PTEs) were detected in surface sediments and the scarce water circulation led to a permanent oxic-hypoxic interface along the water column [3]. This research aims at understanding if and how biogeochemical processes may affect PTE (As, Cr, Hg, Fe, Mn, Ni, Pb, V) mobility and related fluxes at the SWI. Sampling activities were performed before (June) and after September) the forced aeration by means of a system of porous pipes laid on the bottom with the aim to re-oxygenate the water column in summer. Water aliquots were sampled along the water column, short sediment cores were collected to investigate the solid (sediments) and dissolved (porewater) phases and in situ benthic chamber experiments were conducted at the SWI. Results showed that the water column was oxygen stratified and hypoxic conditions were observed in the bottom water layer, mostly in June (2.29 mg/L of dissolved oxygen) when reductive conditions also occurred (-58 mV). Consequently, dissolved PTE concentrations increased with increasing depth and were maximum at the bottom due to dissolution/desorption processes involving Fe and Mn oxy-hydroxides [4]. A gradual oxygen depletion was also observed inside the chamber during the benthic chamber experiments testifying to organic matter remineralisation processes and subsequent increase of dissolved PTEs. Regarding PTE profiles in porewater, the highest PTE concentrations were observed in June, especially at the top of the sedimentary sequence implying that hypoxic conditions may promote the release of PTEs at the SWI.

Background Tumor-associated antigens recognized by humoral effectors of the immune system are a very attractive target for human cancer diagnostics and therapy. Recent advances in molecular techniques have led to molecular definition of immunogenic tumor proteins based on their reactivity with autologous patient sera (SEREX). Methods Several high complexity phage-displayed cDNA libraries from breast carcinomas, human testis and breast carcinoma cell lines MCF-7, MDA-MB-468 were constructed. The cDNAs were expressed in the libraries as fusion to bacteriophage lambda protein D. Lambda-displayed libraries were efficiently screened with sera from patients with breast cancer. Results A panel of 21 clones representing 18 different antigens, including eight proteins of unknown function, was identified. Three of these antigens (T7-1, T11-3 and T11-9) were found to be overexpressed in tumors as compared to normal breast. A serological analysis of the 21 different antigens revealed a strong cancer-related profile for at least five clones (T6-2, T6-7, T7-1, T9-21 and T9-27). Conclusions Preliminary results indicate that patient serum reactivity against five of the antigens is associated with tumor disease. The novel T7-1 antigen, which is overexpressed in breast tumors and recognized specifically by breast cancer patient sera, is potentially useful in cancer diagnosis.

Reliable point-of-care (POC) rapid tests are crucial to detect infection and contain the spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The emergence of several variants of concern (VOC) can reduce binding affinity to diagnostic antibodies, limiting the efficacy of the currently adopted tests, while showing unaltered or increased affinity for the host receptor, angiotensin converting enzyme 2 (ACE2). We present a graphene field-effect transistor (gFET) biosensor design, which exploits the Spike-ACE2 interaction, the crucial step for SARS-CoV-2 infection. Extensive computational analyses show that a chimeric ACE2-Fragment crystallizable (ACE2-Fc) construct mimics the native receptor dimeric conformation. ACE2-Fc functionalized gFET allows in vitro detection of the trimeric Spike protein, outperforming functionalization with a diagnostic antibody or with the soluble ACE2 portion, resulting in a sensitivity of 20 pg/mL. Our miniaturized POC biosensor successfully detects B.1.610 (pre-VOC), Alpha, Beta, Gamma, Delta, Omicron (i.e., BA.1, BA.2, BA.4, BA.5, BA.2.75 and BQ.1) variants in isolated viruses and patient's clinical nasopharyngeal swabs. The biosensor reached a Limit Of Detection (LOD) of 65 cps/mL in swab specimens of Omicron BA.5. Our approach paves the way for a new and reusable class of highly sensitive, rapid and variant-robust SARS-CoV-2 detection systems.

The skin constitutes a protective barrier to external physical and chemical aggressions. Although it is constantly exposed to various xenobiotics, it is generally considered poorly permeable to them, as for example metal ions, becoming unfortunately an entry route of such substances. Metals may penetrate inside the skin inducing more or less local effects such as skin sensitization and potential metals diffusion into the bloodstream. The objective of the study was to investigate the percutaneous penetration of metals in vitro - ex vivo in Franz cell with intact as well damaged skin applying a road dust powder. Moreover, porcine and human skins were compared. This study demonstrated that, after the application of a road dust powder on the skin, metals can penetrate and permeate this cutaneous membrane. From this experimental analysis, in intact skin lead (Pb) achieved the highest skin absorption in both human and porcine skin, while skin absorption profile of cobalt (Co) was the lowest in human skin than the one in porcine model. The concentrations of Ni present in receiving solution were higher compared to other metals in all experiments performed. The present work, definitely shows that metals permeation through damaged skin is accelerated than intact skin, as a result of the weaker cutaneous barrier function. According to published data, pig skin appeared as a suitable model for human skin. Our results confirmed that skin absorption of metals can be relevant in environmental exposures.

The Cananéia-Iguape estuarine–lagoon complex (São Paulo state, Brazil) is a natural laboratory to study metal binding by humic substances (HS) in subtropical settings. This transitional environment is evolving into a freshwater environment due to water input from the Ribeira River, funneled through the Valo Grande Canal (Iguape). Past mining activities in the Ribeira River basin and maritime traffic are suspected to be potential sources of trace metals in the system. In this study, the trace metal contents of Free Humic Acids (FHA), Bound Humic Acids (BHA), and Fulvic Acids (FA) extracted from sedimentary organic matter were investigated. Moreover, the sources of HS were traced using their stable carbon isotope compositions and C/N ratios. The results suggested a mixed marine–terrestrial source of FHA, BHA, and FA. Copper and Cr were the most abundant trace metals bound to HS. On average, Cu showed concentrations of 176, 115, and 37.9 μg g−1 in FHA, BHA, and FA, respectively, whereas Cr showed average concentrations of 47.4, 86.3, and 43.9 μg g−1 in FHA, BHA, and FA, respectively. Marine FHA showed the highest binding capacity for trace metals, whereas terrestrial FA derived from the decay of mangrove organic matter showed the lowest binding capacity.

Children are potentially exposed to products that contain nanoparticles (NPs). In particular, silver NPs are commonly present both in products used by and around children, primarily due to their antibacterial properties. However, very few data are available regarding the ability of silver NPs to penetrate through the oral mucosa in children. In the present work, we used baby porcine buccal mucosa mounted on vertical Franz diffusion cells, as an in vitro model to investigate penetration of silver NPs (19 �� 5 nm). Permeability experiments were performed using pristine physiologically-relevant saline solution in the receiver chamber and known concentrations of NPs or ions in the donor chamber; conditions mimicked the in vivo physiological pH conditions. After physicochemical characterization of silver nanoparticles dispersed in physiological solution, we evaluated the passage of ions and NPs through the mucosa, using single particle inductively coupled plasma mass spectrometry. A flux of 4.1 �� 1.7 ng cm���2 min���1 and a lag time of 159 �� 17 min were observed through mucosa exposed to silver nanoparticles. The latter suggests nanoparticle penetration through the baby porcine mucosa and release Ag+ ions in the receptor fluid, as confirmed by computational model. Due to physiological similarity between human and pig membranes it is reasonable to assume that a trans-oral mucosa penetration could occur in children upon contact with silver nanoparticles.

Mercury (Hg) contamination in the Gulf of Trieste (northern Adriatic Sea) due to mining activity in Idrija (Slovenia) still represents an issue of environmental concern. The Isonzo/Soča River’s freshwater inputs have been identified as the main source of Hg into the Gulf, especially following periods of medium-high discharge. This research aims to evaluate the occurrence and distribution of dissolved (DHg) and particulate (PHg) Hg along the water column in the northernmost sector of the Gulf, a shallow and sheltered embayment suitable for the accumulation of fine sediments. Sediment and water samples were collected under unperturbed and perturbed environmental conditions induced by natural and anthropogenic factors. Mercury in the sediments (0.77–6.39 µg g−1) and its relationship to grain size were found to be consistent with previous research focused on the entire Gulf, testifying to the common origin of the sediment. Results showed a notable variability of DHg (&lt, LOD–149 ng L−1) and PHg (0.39–12.5 ng L−1) depending on the interaction between riverine and marine hydrological conditions. Mercury was found to be mainly partitioned in the suspended particles, especially following periods of high discharge, thus confirming the crucial role of the river inputs in regulating PHg distribution in the Gulf.

The covalent functionalization of (7, 6)-enriched single-walled carbon nanotubes (SWCNTs) with oligophenylenevinylene (OPV) moieties terminating with a dimethylamino group is proposed as an efficient way to enhance the affinity of CNTs with Spiro-MeOTAD in perovskite-based solar cells. The evidence of SWCNTs functionalization and the degree of OPV substitution on SWCNTs are established from TGA, XPS, TEM and Raman techniques. Our tailored doping materials display photovoltaic performances in line with conventional Li-doped spiro-MeOTAD system, showing at the same time a significantly improved chemical stability of the perovskite component over time. Furthermore, the comparison of the photovoltaic performances with those obtained with non-functionalized SWCNTs clearly suggest that the presence of the organic appends ensures highly reproducible PV performances. Our results demonstrate the suitability of this material as a valid doping agent for spiro-MeOTAD, representing a viable alternative to the conventional Li-salt.

In order to simulate a contamination at the processing plant, one batch of freshlyprocessed salami batter (20 kg) was inoculated (1% v:w) with 5 log colony forming unit (CFU)/g of a multi-strain cocktail of two strains of Escherichia coli O157:H7 (registered and wild strain). Another batch was inoculated (1% v:w) with sterile physiological saline solution and used to check the lactic acid bacteria (Lab) behaviour and the changes of physicochemical parameters (pH and aw). Both batches were then processed to obtain a semi-dry salami (Hungarian-style): microbiological and physico-chemical properties were monitored during 94 days of ripening. During the manufacturing process, the levels of pathogen decreased of about 2.18 log CFU/g with respect to the initial inoculated levels. The behaviour of the indigenous bacteria such as Lab and the physico-chemical properties can help to determine the fate of pathogens throughout processing.

The COVID-19 pandemic caused by SARS-CoV-2 has made the development of safe and effective vaccines a critical priority. To date, four vaccines have been approved by European and American authorities for preventing COVID-19, but the development of additional vaccine platforms with improved supply and logistics profiles remains a pressing need. Here we report the preclinical evaluation of a novel COVID-19 vaccine candidate based on the electroporation of engineered, synthetic cDNA encoding a viral antigen in the skeletal muscle. We constructed a set of prototype DNA vaccines expressing various forms of the SARS-CoV-2 spike (S) protein and assessed their immunogenicity in animal models. Among them, COVID-eVax—a DNA plasmid encoding a secreted monomeric form of SARS-CoV-2 S protein receptor-binding domain (RBD)—induced the most potent anti-SARS-CoV-2 neutralizing antibody responses (including against the current most common variants of concern) and a robust T cell response. Upon challenge with SARS-CoV-2, immunized K18-hACE2 transgenic mice showed reduced weight loss, improved pulmonary function, and lower viral replication in the lungs and brain. COVID-eVax conferred significant protection to ferrets upon SARS-CoV-2 challenge. In summary, this study identifies COVID-eVax as an ideal COVID-19 vaccine candidate suitable for clinical development. Accordingly, a combined phase I-II trial has recently started., Graphical abstract, We report the development, characterization, and preclinical evaluation of COVID-eVax, a novel COVID-19 vaccine candidate with improved supply and logistics profiles. The technology is based on the electroporation of engineered, synthetic cDNA encoding a secreted monomeric form of the receptor-binding domain of the SARS-CoV-2 spike protein.

[This corrects the article DOI: 10.3389/fvets.2024.1328284.]., (Copyright © 2024 Dubbert, Meester, Smith, Tobias, Di Bartolo, Johne, Pavoni, Krumova-Valcheva, Sassu, Prigge, Aprea, May, Althof, Ianiro, Żmudzki, Dimitrova, Alborali, D'Angelantonio, Scattolini, Battistelli and Burow.)