Angularly resolved characterization of ion beams from laser-ultrathin foil interactions

Methods and techniques used to capture and analyze beam profiles produced from the interaction of intense, ultrashort laser pulses and ultrathin foil targets using stacks of Radiochromic Film (RCF) and Columbia Resin #39 (CR-39) are presented. The identification of structure in the beam is particularly important in this regime, as it may be indicative of the dominance of specific acceleration mechanisms. Additionally, RCF can be used to deconvolve proton spectra with coarse energy resolution while mantaining angular information across the whole beam

Luminescent Metal-organic frameworks for sensing of pollutants

contamination of soils, water and air by heavy metals, pesticides, gases, dioxins etc. pose a severe treat to environment and human health and affect the future generations. For these reasons, researchers around the world are currently working on developing new materials and technologies to preserve nature and offer a better future for the next generations. Metal-organic frameworks (MOFs) are materials that could help in this challenge thanks to their outstanding properties, extreme flexibility and relative ease of synthesis. In recent years, MOFs are showing that they are not only extremely porous materials and excellent catalysts, but some of them have also interesting optical properties making them good candidates for LEDs and luminescent sensors.[1] In particular, using luminescent MOFs (LMOFs) as sensors for qualitative and quantitative detection of pollutants has notable advantages: the crystalline structure of the MOFs is capable to select and concentrate the analyte and exclude potential interfering species enhancing considerably the sensitivity. Moreover, it is possible to design sensors that could be reused by recovering the MOFs.[2] Two main interaction and transduction mechanisms are possible in luminescent MOFs while used as sensor: on one hand a change in luminescent intensity (quenching or enhancement); on the other hand a change in the position of the emission band.[3] To develop sensors based on LMOFs are possible two different approaches: synthesize intrinsically luminescent MOFs or loading luminescent species (Dyes, QDs etc.) inside the MOFs by exploiting their porosity. In this study, we have synthesized two LMOFs, each one example of these two different approaches presented before and tested as sensors for heavy metal ions in water solutions: the intrinsically luminescent AgBDC and Zr-MOF-808 loaded with luminescent gold clusters Au25@BSA (Au25@MOF-808). AgBDC was synthesized from AgNO3 and terephthalic acid and characterized by XRD and FTIR, and then tested as luminescent sensor for heavy metals ions in water solutions. Our results show that Mn2+ and Hg2+ ions in μM concentrations are capable to quench the luminescence of AgBDC, making this MOFs a promising candidate as luminescent chemosensor for these two metal ions. Meanwhile Au25BSA@MOF-808 was obtained by loading into Zr-MOF-808 luminescent gold clusters Au25@BSA. It was structurally characterized by XRD, FTIR and N2 gas adsorption and later tested as sensor for heavy metals in water. Brillant results were obtained showing how this LMOF acts as highly sensitive sensor for Hg2+ ions in trace concentrations (nM) with very high selectivity, respect to many common metal ions in water solutions. Moreover, the Zr-MOF-808 structure is capable to shield the Au25 clusters from organic pollutants, increasing their selectivity and improves their thermal and temporal stability. Our result shows that AgBDC and Au25@MOF-808 could be used as sensors for heavy metal ions with excellent sensitivity and selectivity. More specifically Au25@MOF-808 is capable to detect Hg2+ in trace concentrations just by simple fluorescence measurements. In addition, these two LMOFs open the way to developments of solid-state sensors based on them for example: coatings, films, polymer matrix membrane which could be easily recovered and reused. These results have strong impact in sensoristics demonstrating that LMOFs can be valid candidates to design efficient, sensitive and selective sensors for pollutants helping us in the continuous environmental monitoring

Investigation on the luminescence properties of bare and Rhodamine B functionalized Zr-MOF-808

Metal organic frameworks (MOFs) are materials well known for their high surface and catalytic properties as well as because they are relatively easy to synthesize and, in some cases, extremely f lexible.[1] Recently, there has been also a growing interest in the optical properties of these materials, particularly in luminescence, which has potential applications in various fields, such as sensors, LEDs, scintillators, and bioimaging agents....

Origin of the solid-state luminescence of MIL-53(Al) and its connection to the local crystalline structure

Metal-organic frameworks (MOFs) are extensively studied due to their unique surface properties, enabling many intriguing applications. Breathing MOFs, a subclass of MOFs, have gained recent interest for their ability to undergo structural changes based on factors like temperature, pressure, adsorbed molecules. Certain MOFs also exhibit remarkable optical properties useful for applications such as sensors, light-emitting diodes, and scintillators. The most promising MOFs possess high porosity, breathing properties, and photoluminescence activities, allowing for improved device responsiveness and selectivity. Understanding the relationship between crystal structures and photoluminescence properties is crucial in these cases. As studies on this topic are still very limited, we report for the first time an exhaustive study on the solid-state luminescence of the breathing MOF MIL-53(Al), that can stabilize in three different crystalline structures: open-pore, hydrated narrow-pore and closed-pore. We unveil a fascinating solid-state luminescence spectrum, comprising three partially overlapping bands, and elucidate the intricate electronic transitions within each band as well as their intimate correlation with the local crystalline structures. Our characterizations of spectroscopic properties and decay times provide a deeper understanding of the luminescent behaviour of MIL-53(Al) and demonstrate that is possible to identify present crystalline structures by optical measurements or to modify the optical properties inducing structural transitions for this type of materials. These insights could help to design next-generation, selective sensors or smart light emitting devices

Inactivating SARS-CoV-2 virus with MOF-composites as smart face masks

Funding: European Research Council. Grant Number: 787073; EPSRC Light Element Analysis Facility. Grant Number: EP/T019298/1; Scottish Funding Council. Grant Number: SFC/AN/08/020 (XRR064); Engineering and Physical Sciences Research Council. Grant Number: EP/R023751/1; Open access funding enabled and organized by Projekt DEAL.The significant impact of the SARS-CoV-2 (COVID-19) pandemic outbreak on people's lives has highlighted the urgent need for effective personal protective equipment. To improve the limited protection of existing surgical face masks, the fabrication of face masks containing porous metal–organic framework (MOF) nanoparticles is proposed. Utilizing low toxicity MOFs, such as Al-Fumarate and HKUST-1(Cu), allows i) the modification of their external surface with active moieties to specifically bind on proteins or virus surfaces, such as the spike protein of the SARS-CoV-2 virus; ii) the adsorption of large amounts of water in their pores, enabling them to dehydrate virus aerosols; and iii) the preparation of MOF-based composites, providing good breathability. To ensure optimal binding, the MOFs are grown in situ on the fabric and then functionalized with test antiviral agents. Carefully evaluating their protein binding performance with bovine albumin serum (BSA) shows a ten-fold higher binding of proteins than surgical face masks. Further plaque assays with a SARS-CoV-2 virus with an incubation period of 30 min verifies the great potential of MOF-composites to effectively reduce the recovered viable SARS-CoV-2 particles up to 99%. Consequently, the smart MOF-composites represent an elegant and innovative approach to effectively combat airborne viruses and reduce their spread.Peer reviewe

Surface functionalized metal-organic frameworks for binding coronavirus proteins

This work was supported by University of St Andrews Restarting Research Funding Scheme (SARRF), funded through the SFC grant reference SFC/AN/08/020 (XRR064) and European Research Council grant ADOR (Advanced Grant 787073). The authors acknowledge the EPSRC Light Element Analysis Facility Grant (EP/T019298/1) and the EPSRC Strategic Equipment Resource Grant (EP/R023751/1).Since the outbreak of SARS-CoV-2, a multitude of strategies have been explored for the means of protection and shielding against virus particles: filtration equipment (PPE) has been widely used in daily life. In this work, we explore another approach in the form of deactivating coronavirus particles through selective binding onto the surface of metal–organic frameworks (MOFs) to further the fight against the transmission of respiratory viruses. MOFs are attractive materials in this regard, as their rich pore and surface chemistry can easily be modified on demand. The surfaces of three MOFs, UiO-66(Zr), UiO-66-NH2(Zr), and UiO-66-NO2(Zr), have been functionalized with repurposed antiviral agents, namely, folic acid, nystatin, and tenofovir, to enable specific interactions with the external spike protein of the SARS virus. Protein binding studies revealed that this surface modification significantly improved the binding affinity toward glycosylated and non-glycosylated proteins for all three MOFs. Additionally, the pores for the surface-functionalized MOFs can adsorb water, making them suitable for locally dehydrating microbial aerosols. Our findings highlight the immense potential of MOFs in deactivating respiratory coronaviruses to be better equipped to fight future pandemics.Publisher PDFPeer reviewe