More Like this

1. Full solar spectrum optical and photothermal characterization of antimony tin oxide (ATO) films with tunable NIR absorptivity for energy-efficient building envelope applications

   https://doi.org/10.1063/5.0284333  

   Elmi, Mohammad; Wang, Julian (October 2025, APL Materials)

   This work investigates the full-spectrum optical and photothermal properties of Antimony Tin Oxide (ATO)-coated glass for application in energy-efficient building glazing. A simple, scalable dip-coating method was employed to deposit ATO films, and their spectral optical performance was characterized across a broad wavelength range of 250 nm–20 µm [UV–Vis–near-infrared (NIR)–mid-infrared (MIR)]. In this study, for the first time, comprehensive optical data, including spectral transmittance, reflectance, absorptance, visible light transmittance, haze, and spectral and total mid-infrared emissivity (5–20 µm), are reported together for the full solar spectrum, along with the photothermal performance. UV–Vis–NIR spectroscopy and Fourier transform infrared analysis were performed for optical characterization, and surface morphology and nanoparticle dispersion were examined using scanning electron microscopy. The results reveal that ATO-coated glass exhibits high photothermal performance with light-to-heat efficiency greater than 65%, while deposition parameters can significantly affect this efficiency. ATO-coated glass shows high transparency in the visible region with strong and tunable spectral absorptance in the near- and mid-infrared regions, which is a critical feature for thermal control in building applications. The ability to fine-tune near-infrared (NIR) absorption through deposition parameters allows for tailored performance suited to specific environmental conditions. In addition, the coated glass shows low reflectance and high total emissivity in the MIR region (>0.9), specifically in the atmospheric window, enabling efficient radiative heat dissipation. By combining the tunable NIR-selective absorption for solar-heat shielding with controllable MIR radiative dissipation, this study identifies ATO as a promising photothermal material for energy-efficient glazed façade technologies. The comprehensive optical data provided in this study are essential for architectural applications and establish a foundation for future research on photothermal materials in building envelope systems. 

   more » « less
2. Linear and multivalent PEGylation of the tobacco mosaic virus and the effects on its biological properties

   https://doi.org/10.3389/fviro.2023.1184095  

   Caballero, Reca Marian; González-Gamboa, Ivonne; Craig, Stephen L.; Steinmetz, Nicole F. (June 2023, Frontiers in Virology)

   Plant virus-based nanoparticles (VNPs) offer a bioinspired approach to the delivery of drugs and imaging agents. The chemical addressability, biocompatibility, and scalable manufacturability of VNPs make them a promising alternative to synthetic delivery platforms. However, VNPs, just like other proteinaceous or synthetic nanoparticles (NPs), are readily recognized and cleared by the immune system and mechanisms such as opsonization and phagocytosis. Shielding strategies, such as PEGylation, are commonly used to mitigate premature NP clearance. Here, we investigated polyethylene glycol (PEG) coatings on the tobacco mosaic virus (TMV), which was used as a model nanocarrier system. Specifically, we evaluated the effects of linear and multivalent PEG coatings at varying chain lengths on serum protein adsorption, antibody recognition, and macrophage uptake. Linear and multivalent PEGs of molecular weights 2,000 and 5,000 Da were successfully grafted onto the TMV at ≈ 20%–60% conjugation efficiencies, and the degree of cross-linking as a function of PEG valency and length was determined. PEGylation resulted in the modulation of TMV–macrophage interactions and reduced corona formation as well as antibody recognition. Linear and multivalent PEG 5,000 formulations (but not PEG 2,000 formulations) reduced α-TMV antibody recognition, whereas shorter, multivalent PEG coatings significantly reduced α-PEG recognition—this highlights an interesting interplay between the NP and the PEG itself in potential antigenicity and should be an important consideration in PEGylation strategies. This work provides insight into the PEGylation of VNPs, which may improve the possibility of their implementation in clinical applications. 

   more » « less
3. The Landscape of Gold Nanocrystal Surface Chemistry

   https://doi.org/10.1021/acs.accounts.3c00109  

   Greskovich, Katherine M.; Powderly, Kelly M.; Kincanon, Maegen M.; Forney, Nathan B.; Jalomo, Catherine A.; Wo, Anita; Murphy, Catherine J. (January 2023, Accounts of Chemical Research)

   ConspectusGold nanoparticles (AuNPs) exhibit unique size- and shape-dependent properties not obtainable at the macroscale. Gold nanorods (AuNRs), with their morphology-dependent optical properties, ability to convert light to heat, and high surface-to-volume ratios, are of great interest for biosensing, medicine, and catalysis. While the gold core provides many fascinating properties, this Account focuses on AuNP soft surface coatings, which govern the interactions of nanoparticles with the local environments. Postmodification of AuNP surface chemistry can greatly alter NP colloidal stability, nano-bio interactions, and functionality. Polyelectrolyte coatings provide controllable surface-coating thickness and charge, which impact the composition of the acquired corona in biological settings. Covalent modification, in which covalently bound ligands replace the original capping layer, is often performed with thiols and disulfides due to their ability to replace native coatings. N-heterocyclic carbenes and looped peptides expand the possible functionalities of the ligand layer.The characterization of surface ligands bound to AuNPs, in terms of ligand density and dynamics, remains a challenge. Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for understanding molecular structures and dynamics. Our recent NMR work on AuNPs demonstrated that NMR data were obtainable for ligands on NPs with diameters up to 25 nm for the first time. This was facilitated by the strong proton NMR signals of the trimethylammonium headgroup, which are present in a distinct regime from other ligand protons’ signals. Ligand density analyses showed that the smallest AuNPs (below 4 nm) had the largest ligand densities, yet spin–spin T2 measurements revealed that these smallest NPs also had the most mobile ligand headgroups. Molecular dynamics simulations were able to reconcile these seemingly contradictory results.While NMR spectroscopy provides ligand information averaged over many NPs, the ligand distribution on individual particles’ surfaces must also be probed to fully understand the surface coating. Taking advantage of improvements in electron energy loss spectroscopy (EELS) detectors employed with scanning transmission electron microscopy (STEM), a single-layer graphene substrate was used to calibrate the carbon K-edge EELS signal, allowing quantitative imaging of the carbon atom densities on AuNRs with sub-nanometer spatial resolution. In collaboration with others, we revealed that the mean value for surfactant-bilayer-coated AuNRs had 10–30% reduced ligand density at the ends of the rods compared to the sides, confirming prior indirect evidence for spatially distinct ligand densities.Recent work has found that surface ligands on nanoparticles can, somewhat surprisingly, enhance the selectivity and efficiency of the electrocatalytic reduction of CO2 by controlling access to the active site, tuning its electronic and chemical environment, or denying entry to impurities that poison the nanoparticle surface to facilitate reduction. Looking to the future, while NMR and EELS are powerful and complementary techniques for investigating surface coatings on AuNPs, the frontier of this field includes the development of methods to probe the surface ligands of individual NPs in a high-throughput manner, to monitor nano-bio interactions within complex matrices, and to study structure–property relationships of AuNPs in biological systems. 

   more » « less
4. Redox-Active Polymer-Grafted Particles as Redox Mediators for Enhanced Charge Transport in Solution-State Electrochemical Systems

   Avais, M; Thakur, R; Fox, E; Lutkenhaus, J; Pentzer, E (March 2025, Chemical science)

   Efficient charge transport pathways in solutions of redox-active polymers are essential for advancing nextgeneration energy storage systems. Herein, we report the grafting of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) and poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate) (PTMA) polymer brushes onto silica particles with different molecular weights and grafting densities, and the impact of these composite particles in solutions of PTMA. The polymer-grafted particles are characterized using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) techniques. The grafted polymers have molecular weights of 2.5 kDa and 5.0 kDa, with corresponding grafting densities of 0.688 and 0.378 chains nm−2 for SiO2-PTMA-2.5k and SiO2-PTMA-5k, respectively, with the grafting density decreasing with increasing graft length. To investigate the effect of these composite particles on charge transport in solutions of PTMA, different concentrations of the grafted particles were added to solutions of PTMA of different concentrations (near overlap concentration, C*) in 0.1 M LiTFSI in acetonitrile. Electrochemical analysis reveals that below C* the addition of SiO2-PTMA-5k increases the apparent diffusion coefficient (Dapp) 15.2% to 1.041 × 10−6 cm2 s−1 , the exchange rate constant (kex,app) by 9.5% to 1.546 × 1011 L mol−1 s−1, and the heterogeneous electron transfer rate constant (k0) by 24.6%, to 5.526 × 10−4 cm s−1. These results indicate that the synergistic interactions between unbound PTMA polymer chains in solution and PTMA-grafted particles facilitate interchain charge transfer kinetics. This highlights that grafted redoxactive particles can enhance charge transport without the limitations of polymer-only solutions (e.g., chain entanglement) and presents a promising design strategy for high-performance electrochemical applications, such as redox flow batteries (RFBs). 

   more » « less
5. Zwitterlation mitigates protein bioactivity loss in vitro over PEGylation

   https://doi.org/10.1039/c8sc01777h  

   Han, Yanjiao; Yuan, Zhefan; Zhang, Peng; Jiang, Shaoyi (November 2018, Chemical Science)

   Conjugation with poly(ethylene glycol) (PEG) or PEGylation is a widely used tool to overcome the shortcomings of native proteins, such as poor stability, inadequate pharmacokinetic (PK) profiles, and immunogenicity. However, PEGylation is often accompanied by an unwanted detrimental effect on bioactivity, particularly, resulting from the amphiphilic nature of PEG. This is especially true for PEGylated proteins with large binding targets. Pegasys, a PEGylated interferon alpha-2a (IFN-α2a) bearing a 40 kDa branched PEG, is a typical example that displays only 7% in vitro activity of the unmodified IFN-α2a. In this work, by employing IFN-α2a as a model protein, we demonstrated that a protein conjugated with zwitterionic polymers (or zwitterlation) could significantly mitigate the antiproliferative bioactivity loss in vitro after polymer conjugation. The retained antiproliferative activity of zwitterlated IFN-α2a is 4.4-fold higher than that of the PEGylated IFN-α2a with the same polymer molecular weight, or 3-fold higher than that of the PEGylated IFN-α2a with a similar hydrodynamic size. It is hypothesized that nonspecific interactions between zwitterionic polymers and IFN-α2a/IFN-α2a receptors can be mitigated due to the super-hydrophilic nature of zwitterionic polymers. This, in turn, reduces the ‘nonspecific blocking’ between IFN-α2a and IFN-α2a receptors. In addition, we demonstrated that zwitterlated IFN-α2a showed a prolonged circulation time and a mitigated accelerated blood clearance after repeated injections in rats. 

   more » « less