Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Modular Attachment of Nanoparticles on Microparticle Supports via Multifunctional Polymers

Nanoparticles are key to a range of applications, due to the properties that emerge as a result of their small size. However, their size also presents challenges to their processing and use, especially in relation to their immobilization on solid supports without losing their favorable functionalities. Here, we present a multifunctional polymer-bridge-based approach to attach a range of presynthesized nanoparticles onto microparticle supports. We demonstrate the attachment of mixtures of different types of metal-oxide nanoparticles, as well as metal-oxide nanoparticles modified with standard wet chemistry approaches. We then show that our method can also create composite films of metal and metal-oxide nanoparticles by exploiting different chemistries simultaneously. We finally apply our approach to the synthesis of designer microswimmers with decoupled mechanisms of steering (magnetic) and propulsion (light) via asymmetric nanoparticle binding, aka Toposelective Nanoparticle Attachment. We envision that this ability to freely mix available Nanoparticle ability freely nanoparticles to produce composite films will help bridge the fields of catalysis, nanochemistry, and active matter toward new materials and applications.ISSN:0897-475

Microswimmers from Toposelective Nanoparticle Attachment

Microswimmers hold promise for applications ranging from targeted delivery to enhanced mixing at the microscale. However, current fabrication techniques suffer from limited throughput and material selection. Here, a versatile route enabling the synthesis of microswimmers from off-the-shelf micro- and nano-particles is demonstrated. The protocol hinges on the toposelective attachment of photocatalytic nanoparticles onto microparticles, exploiting a multi-functional polymer and a Pickering-wax emulsification step, to yield large quantities of photo-responsive active Janus particles. The polymer presents both silane and nitrocatechol groups, binding silica microspheres to a range of metal oxide nanoparticles. The Pickering-wax emulsions protect part of the microspheres' surface, enabling asymmetric functionalization, as required for self-propulsion. The resulting photocatalytic microswimmers display a characteristic orientation-dependent 3D active motion upon ultra-violet illumination, different from that conventionally described in the literature. By connecting the extensive library of heterogeneous nanoparticle photocatalysts with the nascent field of active matter, this versatile material platform lays the groundwork toward designer microswimmers, which can swim by catalyzing a broad range of chemical reactions with potential for future applications.ISSN:1616-3028ISSN:1616-301

Microswimmers from Scalable Galvanic Displacement

Microswimmers are small particles capable of converting available energy sources into propulsion owing to their compositional asymmetry, and are promising for applications ranging from targeted delivery to enhanced mixing at the microscale. However, current fabrication techniques demonstrate limited scalability and/or rely on the excessive use of expensive precursor materials. Here, a scalable Pickering-wax emulsion technique is combined with galvanic electrochemistry, to grow platinum films from copper nanoparticles asymmetrically seeded onto SiO₂ microparticle supports. In this manner, large quantities of Pt-SiO₂ Janus microswimmers are obtained. Utilizing copper as a templating material not only has the potential to reduce synthesis time, material costs, and toxic waste, but also facilitates the further extension of this methodology to a range of functional materials. This electrochemical approach builds upon previous attempts to overcome the current limitations in microswimmer synthesis and offers exciting opportunities for their future development.ISSN:0934-0866ISSN:1521-411

3-D rotation tracking from 2-D images of spherical colloids with textured surfaces

Tracking the three-dimensional rotation of colloidal particles is essential to elucidate many open questions, e.g. concerning the contact interactions between particles under flow, or the way in which obstacles and neighboring particles affect self-propulsion in active suspensions. In order to achieve rotational tracking, optically anisotropic particles are required. We synthesise here rough spherical colloids that present randomly distributed fluorescent asperities and track their motion under different experimental conditions. Specifically, we propose a new algorithm based on a 3-D rotation registration, which enables us to track the 3-D rotation of our rough colloids at short time-scales, using time series of 2-D images acquired at high frame rates with a conventional wide-field microscope. The method is based on the image correlation between a reference image and rotated 3-D prospective images to identify the most likely angular displacements between frames. We first validate our approach against simulated data and then apply it to the cases of: particles flowing through a capillary, freely diffusing at solid-liquid and liquid-liquid interfaces, and self-propelling above a substrate. By demonstrating the applicability of our algorithm and sharing the code, we hope to encourage further investigations in the rotational dynamics of colloidal systems.ISSN:1744-683XISSN:1744-684

Sub-nanoscale Surface Engineering of TiO2 Nanoparticles by Molecular Layer Deposition of Poly(ethylene terephthalate) for Suppressing Photoactivity and Enhancing Dispersibility

In this work, we report molecular layer deposition (MLD) of ultrathin poly(ethylene terephthalate) (PET) films on gram-scale batches of ultrafine particles for the first time. TiO2 P25 nanoparticles (NPs) are coated up to 50 cycles in an atmospheric-pressure fluidized-bed reactor at ∼150 °C using terephthaloyl chloride and ethylene glycol as precursors. Ex-situ diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis, and transmission electron microscopy show the linear growth at ∼0.05 nm/cycle of uniform and conformal PET films, which are unattainable with conventional wet-phase approaches. The sub-nanoscale and nanoscale PET films not only suppress the photocatalytic activity of TiO2 NPs by hindering the access of water and reactant molecules to the TiO2 surface but also improve the dispersibility of TiO2 NPs in both organic and aqueous media. Still, the bulk optical properties, electronic structure, and surface area of TiO2 are essentially unaffected by the MLD process. This study demonstrates the industrial relevance of MLD to simultaneously suppress the photoactivity and enhance the dispersibility of commercial TiO2 P25 nanopowders, which is crucial for their use for example as UV-screening agents in sunscreens and as white pigments in paints. Moreover, by rapidly modifying the surface properties of particles in a controlled manner at the sub-nanometer scale, particle MLD can serve many other applications ranging from nanofluids to emulsions to polymer nanocomposites.ISSN:2574-097

Drug powders with tunable wettability by atomic and molecular layer deposition: From highly hydrophilic to superhydrophobic

The wettability of pharmaceuticals is a key physical property which influences their dissolution rate, dispersibility, flowability and solid-state stability. Here, we provide a platform of surface nanoengineering methods capable of tuning the wettability of drug powders from high hydrophilicity to superhydrophobicity with drug loadings up to 95–99%. Specifically, we functionalize gram-scale micronized budesonide, a commercial active pharmaceutical ingredient for respiratory diseases, in a vibrated fluidized bed reactor with inorganic Al2O3, TiO2 and SiO2 by atomic layer deposition (ALD), organic poly(ethylene terephthalate) (PET) by molecular layer deposition (MLD) and inorganic/organic titanicone by hybrid ALD/MLD. Transmission electron microscopy shows the formation of smooth and uniform films for each deposition process without significantly affecting the surface morphology of the budesonide particles. Crucially, the deposition processes do not alter the solid-state structure and cytocompatibility of budesonide. The ceramic ALD films are able to convert the originally hydrophobic budesonide into highly hydrophilic powders with water contact angles (WCAs) of ~10° within a few seconds. The purely organic PET films grown via MLD deliver superhydrophobic powders with a WCA of 145–150°. In contrast, the titanicone hybrid ALD/MLD films lead to mild hydrophilicity with WCAs ranging from ~80° to ~60°. Modifying the wetting properties of inhaled drug powders such as budesonide is relevant to improve bioavailability, enhance the dispersion of formulations in suspension-based inhalers or prevent moisture interactions in dry powder inhalers. Moreover, by tuning the surface chemical composition at the atomic or molecular level, particle ALD, MLD and hybrid ALD/MLD enable control over powder wettability for several pharmaceutical dosage forms with applications in oral, orally inhaled and parenteral delivery.</p

Subnano Surface Engineering of TiO2 Nanoparticles by PET Molecular Layer Deposition: Tuning Photoactivity and Dispersibility

In this work, we report molecular layer deposition (MLD) of ultrathin poly(ethylene terephthalate) (PET) films on gram-scale batches of ultrafine particles for the first time. TiO2 P25 nanoparticles (NPs) are coated up to 50 cycles in an atmospheric-pressure fluidized bed reactor at 150 °C using terephthaloyl chloride and ethylene glycol as precursors. Ex-situ diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis and transmission electron microscopy show the linear growth at 0.05 nm/cycle of uniform and conformal PET films, which are unattainable with conventional wet-phase approaches. The subnano and nano PET films not only suppress the photocatalytic activity of TiO2 NPs by reducing the generation of hydroxyl radicals, but also improve the dispersibility of TiO2 NPs in both organic and aqueous media. Still, the bulk optical properties, electronic structure and surface area of TiO2 are essentially unaffected by the MLD process. This study demonstrates the industrial relevance of MLD to simultaneously tune the photoactivity and dispersibility of the commercial photocatalyst TiO2 P25. Moreover, by rapidly modifying the surface properties of particles in a controlled manner at the subnanometer scale, particle MLD can serve many applications ranging from nanofluids to emulsions to polymer nanocomposites