Can the UK 'Netflix' Payment Model Boost the Antibacterial Pipeline?

The silent pandemic of antimicrobial resistance (AMR) is a global issue needing prompt attention. A comprehensive one-health approach across human and animal health, agriculture and the environment is needed to solve this, addressing overuse of antibacterials, and of course, optimising measures for preventing and controlling infection. We also need a robust pipeline of new antibacterials. However, the current pipeline is inadequate and several companies with new antibacterials have gone bankrupt due to low sales, leading to a 'broken market'. To address this, the UK has completed a project using novel approaches to value assessment and reimbursement for two antibacterials. The new funding arrangements for these products commenced on 1st July 2022, delinking reimbursement from volume of sales; a so-called 'pull incentive', with payments based on the added value to the whole-health and social-care system, not just to individual patients. This article describes how the project was devised, developed, and progressed. The learning from this work might help other countries to adopt or adapt the approach to fit with their national systems, and collectively achieve a global incentive to reinvigorate the antibacterial pipeline.

Modelling materials for solar fuel synthesis by artificial photosynthesis; predicting the optical, electronic and redox properties of photocatalysts.

In this mini-review, we discuss what insight computational modelling can provide into the working of photocatalysts for solar fuel synthesis and how calculations can be used to screen for new promising materials for photocatalytic water splitting and carbon dioxide reduction. We will extensively discuss the different relevant (material) properties and the computational approaches (DFT, TD-DFT, GW/BSE) available to model them. We illustrate this with examples from the literature, focussing on polymeric and nanoparticle photocatalysts. We finish with a perspective on the outstanding conceptual and computational challenges.

Chemical trends in the optical properties of rocksalt nanoparticles.

The nature and magnitude of the optical gaps of rocksalt alkaline earth (MgO, CaO, SrO, MgS, MgSe) and transition metal chalcogenide (CdO, PbS) nanoparticles are studied using time-dependent density functional theory (TD-DFT) calculations on (MX)32 nanoparticles. We demonstrate, just as we previously showed for MgO, that TD-DFT calculations on rocksalt nanoparticles require the use of hybrid exchange-correlation (XC-)functionals with a high percentage of Hartree-Fock like exchange (e.g. BHLYP) or range-separated XC-functionals to circumvent problems related to the description of charge-transfer excitations. Concentrating on the results obtained with TD-BHLYP we show that the optical gap in rocksalt nanoparticles displays a wide range of behavior; ranging from large optical gaps stemming from a localized excitation involving corner atoms in alkaline earth oxides to a delocalized excitation and small optical gaps in the transition metal chalcogenides. Finally, we rationalize this wide range of behaviour in terms of differences in the degree to which the Coulombic interaction between the excited electron and hole is screened in the different nanoparticles, and relate it to the optical dielectric constants of the bulk materials the nanoparticles are made from.

Optical excitation of MgO nanoparticles; a computational perspective.

The optical absorption spectra of magnesium oxide (MgO) nanoparticles, along with the atomic centres responsible, are studied using a combination of time-dependent density functional theory (TD-DFT) and coupled-cluster methods. We demonstrate that TD-DFT calculations on MgO nanoparticles require the use of range-separated exchange-correlation (XC-) functionals or hybrid XC-functionals with a high percentage of Hartree-Fock like exchange to circumvent problems related to the description of charge-transfer excitations. Furthermore, we show that the vertical excitations responsible for the experimentally studied range of the spectra of the MgO nanoparticles typically involve both 3-coordinated corner sites and 4-coordinated edge sites. We argue therefore that to label peaks in these absorption spectra exclusively as either corner or edge features does not provide insight into the full physical picture.