Graham J. Leggett’s research while affiliated with The University of Sheffield and other places

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Publications (203)


Achieving High Quality Factor Interband Nanoplasmonics in the Deep Ultraviolet Spectrum via Mode Hybridization
  • Article

February 2025

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19 Reads

Nano Letters

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Yan Liu

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Interband plasmons (IBPs) enable plasmonic behavior in nonmetallic materials, such as semiconductors. Originating from interband electronic transitions, IBPs are characterized by negative real permittivity that can extend into deep ultraviolet (DUV) spectrum, as demonstrated using silicon. However, the practical applications of IBPs are limited by their inherently broad resonances. In this study, we address this limitation by hybridizing the localized plasmon resonance of silicon nanostructures with the Fabry–Pérot resonance of a SiO2 dielectric layer atop a silicon substrate. This design achieves a simulated quality factor (Q-factor) of ∼43, with experimental measurements yielding a Q-factor of 37 at ∼4.6 eV within the DUV region. Furthermore, we demonstrate a 5.4-fold enhancement in DUV absorption for lignin-modified polyethylene glycol films when integrated with the hybridized DUV cavity, showcasing the potential for UV blocking applications. Our findings offer a versatile platform that can be adapted to other IBP systems and open new opportunities in UV-specific applications.


Figure 1. Nile red and Coumarin-7 are FRET acceptors with DPH donor in the presence of an αHB. (a) Surface and cartoon representation of the heptameric αHB crystal structure (PDB code 6g66). The hydrophobic channel is depicted by red sticks. (b−d) Steady-state emission spectra after DPH excitation within the heptamer with (b) Nile red, (c) Coumarin-7, and (d) Methyl orange. Conditions: λ ex = 352 nm, 3 μM potential acceptor 3 μM DPH, 5 μM peptide assembly, HEPES, 10% v/v MeCN, pH 7. Key: DPH emission spectrum, blue line; acceptor emission spectrum, broken black line; mixed DPH + acceptor emission spectrum, red line.
Figure 2. Screening for αHBs that coencapsulate DPH and Nile red. (a) Apparent steady-state FRET efficiency for the 15 screened peptides with the heptamer in blue (#1); the octamer, green (#2); the hexamer, red (#4); and the remaining peptides, orange. E app = I acceptor I acceptor I donor ( ) ( ) ( ) + . 2D excitation−emission spectra and the saturation binding curves for the top two hits: (b) the heptamer, (c) the octamer, and (d) a negative hit, the hexamer. F/F max : normalized fluorescence at 450 nm (DPH, blue) or 593 nm (Nile red, red). Fluorescence conditions: 3 μM Nile red, 3 μM DPH, 5 μM peptide assembly. Saturation binding curve conditions: 0.5 μM DPH or Nile red, 0−30 μM peptide assembly, data are the mean of three independent repeats, and error bars represent the standard deviation from the mean. All data collected in HEPES, 10% v/v MeCN, pH 7. See Table S1 for peptide biophysical data and sequences. See Figure S8 for the steady-state FRET spectra.
Figure 3. TCSPC and transient absorption measurements reveal ultrafast FRET between DPH and Nile red. (a) Fluorescence decay in the heptamer for DPH (blue) and Nile red (red) after excitation at 352 nm. (b) Wavelength resolved transient absorption of the heptamer for DPH and Nile red after 352 nm excitation for 8 different pump−probe time delays. ΔmOD: change in milli-optical density. (c) Kinetics obtained by integration over the Nile red stimulated emission signal for the heptamer with Nile red after 535 nm excitation (black circles) and the heptamer with DPH and Nile red using 352 nm photoexcitation (red circles), and overlaid fits (solid lines). (d) Early time dynamics of the data shown in (c) illustrating the difference between photoexcitation of DPH or Nile red on the Nile red stimulation emission kinetics. (e) Kinetic model of FRET and radiative decay pathways determined for DPH and Nile red in the heptamer. Similar time constants were obtained for the octamer (Tables S5− S9). TCSPC conditions: 3 μM DPH and Nile red, 5 μM peptide assembly, HEPES, 10% v/v MeCN, pH 7. TA conditions: 10 μM DPH and Nile red, 15 μM peptide assembly, HEPES, 10% v/v MeCN, pH 7. For TCSPC fitting parameters and time-resolved emission spectra, see Tables S5− S8, Figures S22 and S23. For TA fitting parameters and wavelength resolved transient absorption, see Table S9 and Figure S26.
Figure 4. Free energy landscape sampling the distance between DPH (blue) and Nile red (red) within the αHBs. (a) The heptamer has two minima at 3.5 Å (−93 ± 5 kJ mol −1 ) and 10.0 Å (−92 ± 1 kJ mol −1 ). (b) The octamer shows a broad global minimum at 4.1 Å (−94.6 ± 2 kJ mol −1 ). 3 ×1 μs simulations were started independently from the starting poses in Figures S29 and S35. Standard deviation from the mean is shown in pale blue.
Figure 5. αHB channel dimensions control anthracene photodimerization in aqueous solution. (a) Lowest energy AutoDock Vina poses (both −18.7 kcal mol −1 dimer) for anthracene dimer in the heptamer, showing reactive (1) and offset (2) conformations. (b) Induced CD signal upon anthracene binding to the heptamer and the hexamer. (c) Decrease in anthracene emission upon irradiation at 365 nm. Color key same as in (b): hexamer, red; heptamer, blue; trimer, green; MeCN, purple; buffer, orange. (d) Proton NMR spectra without illumination (top) and after 30 min of excitation at 365 nm (bottom) for anthracene dimerization reaction within the heptamer. Conditions: 14 μM anthracene, 7 μM peptide assembly, HEPES, 10% v/v MeCN, pH 7, and peptides were removed before collecting NMR data.
Confinement and Catalysis within De Novo Designed Peptide Barrels
  • Article
  • Full-text available

January 2025

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23 Reads

Journal of the American Chemical Society

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Covalent Capture of Nanoparticle-Stabilized Oil Droplets via Acetal Chemistry Using a Hydrophilic Polymer Brush

December 2024

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15 Reads

Langmuir

We report the capture of nanosized oil droplets using a hydrophilic aldehyde-functional polymer brush. The brush was obtained via aqueous ARGET ATRP of a cis-diol-functional methacrylic monomer from a planar silicon wafer. This precursor was then selectively oxidized using an aqueous solution of NaIO4 to introduce aldehyde groups. The oil droplets were prepared by using excess sterically stabilized diblock copolymer nanoparticles to prepare a relatively coarse squalane-in-water Pickering emulsion (mean droplet diameter = 20 μm). This precursor was then further processed via high-pressure microfluidization to produce ∼200 nm squalane droplets. We demonstrate that adsorption of these nanosized oil droplets involves acetal bond formation between the cis-diol groups located on the steric stabilizer chains and the aldehyde groups on the brush. This interaction occurs under relatively mild conditions and can be tuned by adjusting the solution pH. Hence this is a useful model system for understanding oil droplet interactions with soft surfaces.


Figure 1. Nile Red and Coumarin-7 are FRET acceptors with DPH donor in the presence of an HB. (a) Surface representation of the heptamer HB crystal structure (PDB code 6g66). Colored by chain. (b -d) Steady-state emission spectra after DPH excitation within the heptamer with (b) Nile Red, (c) Coumarin-7 and (d) Methyl orange. Conditions: λex = 352 nm, 3 μM potential acceptor 3 μM DPH, 5 μM peptide assembly, HEPES, 10% v/v MeCN, pH 7. Key: DPH emission spectrum, blue line; acceptor emission spectrum, broken black line; mixed DPH + acceptor emission spectrum, red line.
Confinement and Catalysis Within De Novo Designed Peptide Barrels

August 2024

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36 Reads

De novo protein design has advanced such that many peptide assemblies and protein structures can be generated predictably and quickly. The drive now is to bring functions to these structures, for example, small-molecule binding and catalysis. The formidable challenge of binding and orienting multiple small molecules to direct chemistry is particularly important for paving the way to new functionalities. To address this, here we describe the design, characterization, and application of small-molecule:peptide ternary complexes in aqueous solution. This uses α-helical barrel (αHB) peptide assemblies, which comprise 5 or more α-helices arranged around central channels. These channels are solvent accessible, and their internal dimensions and chemistries can be altered predictably. Thus, αHBs are analogous to ‘molecular flasks’ made in supramolecular, polymer, and materials chemistry. Using Förster resonance energy transfer as a readout, we demonstrate that specific αHBs can accept two different organic dyes, 1,6-diphenyl-1,3,5-hexatriene and Nile Red in close proximity. In addition, two anthracene molecules can be accommodated within an αHB to promote photocatalytic anthracene-dimer formation. However, not all ternary complexes are productive, either in energy transfer or photocatalysis, illustrating the control that can be exerted by judicious choice and design of the αHB.


XPS Depth-Profiling Studies of Chlorophyll Binding to Poly(cysteine methacrylate) Scaffolds in Pigment-Polymer Antenna Complexes Using a Gas Cluster Ion Source

July 2024

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31 Reads

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2 Citations

Langmuir

X-ray photoelectron spectroscopy (XPS) depth-profiling with an argon gas cluster ion source (GCIS) was used to characterize the spatial distribution of chlorophyll a (Chl) within a poly(cysteine methacrylate) (PCysMA) brush grown by surface-initiated atom-transfer radical polymerization (ATRP) from a planar surface. The organization of Chl is controlled by adjusting the brush grafting density and polymerization time. For dense brushes, the C, N, S elemental composition remains constant throughout the 36 nm brush layer until the underlying gold substrate is approached. However, for either reduced density brushes (mean thickness ∼20 nm) or mushrooms grown with reduced grafting densities (mean thickness 6–9 nm), elemental intensities decrease continuously throughout the brush layer, because photoelectrons are less strongly attenuated for such systems. For all brushes, the fraction of positively charged nitrogen atoms (N⁺/N⁰) decreases with increasing depth. Chl binding causes a marked reduction in N⁺/N⁰ within the brushes and produces a new feature at 398.1 eV in the N1s core-line spectrum assigned to tetrapyrrole ring nitrogen atoms coordinated to Zn²⁺. For all grafting densities, the N/S atomic ratio remains approximately constant as a function of brush depth, which indicates a uniform distribution of Chl throughout the brush layer. However, a larger fraction of repeat units bound to Chl is observed at lower grafting densities, reflecting a progressive reduction in steric congestion that enables more uniform distribution of the bulky Chl units throughout the brush layer. In summary, XPS depth-profiling using a GCIS is a powerful tool for characterization of these complex materials.


Transcending Lifshitz Theory: Reliable Prediction of Adhesion Forces between Hydrocarbon Surfaces in Condensed Phases Using Molecular Contact Thermodynamics

June 2024

Langmuir

Lifshitz theory is widely used to calculate interfacial interaction energies and underpins established approaches to the interpretation of measurement data from experimental methods including the surface forces apparatus and the atomic force microscope. However, a significant limitation of Lifshitz theory is that it uses the bulk dielectric properties of the medium to predict the work of adhesion. Here, we demonstrate that a different approach, in which the interactions between molecules at surfaces and in the medium are described by a set of surface site interaction points (SSIPs), yields interaction free energies that are correlated better with experimentally determined values. The work of adhesion W(Lifshitz) between hydrocarbon surfaces was calculated in 260 liquids using Lifshitz theory and compared with interaction free energies ΔΔG calculated using the SSIP model. The predictions of these models diverge in significant ways. In particular, ΔΔG values for hydrocarbon surfaces are typically small and vary little, but in contrast, W(Lifshitz) values span 4 orders of magnitude. Moreover, the SSIP model yields significantly different ΔΔG values in some liquids for which Lifshitz theory predicts similar values of W(Lifshitz). These divergent predictions were tested using atomic force microscopy. Experimentally determined works of adhesion were closer to the values predicted using the SSIP model than Lifshitz theory. In mixtures of methanol and benzyl alcohol, even greater differences were found in the interaction energies calculated using the two models: the value of ΔΔG calculated using the SSIP model declines smoothly as the benzyl alcohol concentration increases, and values are well correlated with experimental data; however, W(Lifshitz) decreases to a minimum and then increases, reaching a larger value for benzyl alcohol than for methanol. We conclude that the SSIP model provides more reliable estimates of the work of adhesion than Lifshitz theory.


Capturing Enzyme-Loaded Diblock Copolymer Vesicles Using an Aldehyde-Functionalized Hydrophilic Polymer Brush

June 2024

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68 Reads

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2 Citations

Langmuir

Compared to lipids, block copolymer vesicles are potentially robust nanocontainers for enzymes owing to their enhanced chemical stability, particularly in challenging environments. Herein we report that cis-diol-functional diblock copolymer vesicles can be chemically adsorbed onto a hydrophilic aldehyde-functional polymer brush via acetal bond formation under mild conditions (pH 5.5, 20 °C). Quartz crystal microbalance studies indicated an adsorbed amount, Γ, of 158 mg m–2 for vesicle adsorption onto such brushes, whereas negligible adsorption (Γ = 0.1 mg m–2) was observed for a control experiment conducted using a cis-diol-functionalized brush. Scanning electron microscopy and ellipsometry studies indicated a mean surface coverage of around 30% at the brush surface, which suggests reasonably efficient chemical adsorption. Importantly, such vesicles can be conveniently loaded with a model enzyme (horseradish peroxidase, HRP) using an aqueous polymerization-induced self-assembly formulation. Moreover, the immobilized vesicles remained permeable toward small molecules while retaining their enzyme payload. The enzymatic activity of such HRP-loaded vesicles was demonstrated using a well-established colorimetric assay. In principle, this efficient vesicle-on-brush strategy can be applied to a wide range of enzymes and functional proteins for the design of next-generation immobilized nanoreactors for enzyme-mediated catalysis.


Pipeline for rationally seeded computational design of de novo protein folds
a, Robust sequence-to-structure relationships for coiled-coil oligomers were used as rules to seed the design of new protein scaffolds. b,c, Antiparallel (b) and parallel (c) α-helical barrel protein design targets. For both targets, MASTER51,52 was used to search known experimental protein structures for segments with the potential to connect adjacent helices and generate single-chain models. For the antiparallel designs (b), the sequences and structures of identified short connectors were used directly. However, the parallel targets required longer structured loops (c), for which we targeted helix–turn–helix–turn–helix motifs. ProteinMPNN⁸ and AlphaFold2 (refs. 55,56) were then used iteratively to optimize the sequences and models of these three-helix bundle motifs. d, For each design, a small number of synthetic genes were made and expressed in E. coli for biophysical and structural characterization. Peptide and protein chains are shown in chainbows from the N termini to the C termini (blue to red), except for the initially placed central helices of the helix–turn–helix–turn–helix motifs in the parallel designs, which are shown in white. α-HB, α-helical barrel.
Biophysical and structural characterization of the apCC-Hex peptide and the sc-apCC-6-LLIA protein
a, Helical-wheel representation of part of an antiparallel α-helical barrel highlighting the a–g heptad repeats: red, a sites; green, d sites; magenta, g sites; and cyan, e sites; N and C labels refer to the termini of the helices closest to the viewer. b–d, X-ray crystal structure (1.4-Å resolution) of apCC-Hex (PDB ID, 8QAB). Coiled-coil regions identified by Socket2 (ref. ⁷²) (packing cutoff, 7.0 Å) are colored as chainbows from N termini to C termini (blue to red) (b,c). d, A slice through the structure of a heptad repeat with KIH packing colored the same as in the helical wheel in a. e–h, Comparison of the biophysical data for the apCC-Hex α-helical barrel peptide (gray) and the sc-apCC-6-LLIA α-helical barrel protein (green). Circular dichroism spectra were recorded at 5 °C (e). f, Thermal responses of the α-helical circular dichroism signal at 222 nm. g, AUC sedimentation velocity data at 20 °C are fitted to a single-species model; fits returned a peptide assembly of 18.7 kDa (hexamer) and a protein of 24.0 kDa (monomer). h, Fitted data for DPH binding to the peptide and protein; fits returned dissociation constant (Kd) values of 0.8 ± 0.3 µM and 4.0 ± 0.4 µM, respectively. Fitted data are the mean and s.d. of three independent repeats. i, SEC-SAXS data for sc-apCC-6-LLIA fitted using FoXS57,58 to an AlphaFold2 model of the design (χ² = 1.50). j, X-ray crystal structure (2.25 Å) of sc-apCC-6-LLIA (PDB ID, 8QAD) with coiled-coil regions identified by Socket2 (ref. ⁷²) (packing cutoff, 7.0 Å) colored as chainbows. k, A slice through the structure of a heptad repeat showing KIH packing, colored as in a. l,m, Overlays of the experimental apCC-Hex (gray) and sc-apCC-6-LLIA protein (green) structures (RMSD for backbone atoms (RMSDbb) = 1.177 Å). The conditions were as follows: circular dichroism spectroscopy, 50 µM peptide, 10 µM protein in PBS, pH 7.4; AUC, 100 µM peptide, 15 µM protein in PBS, pH 7.4; DPH binding, oligomer concentration was 0–30 µM peptide, 0–30 µM protein in PBS, pH 7.4, 20 °C, final concentration was 1 µM DPH (5% v/v DMSO); SEC-SAXS, 10 mg ml⁻¹ protein in PBS, pH 7.4. deg., degrees; MRE, mean residue ellipticity; res., residue.
Source data
Biophysical and structural characterisation of sc-CC-7 de novo proteins
a, Helical-wheel representation for part of a parallel single-chain α-helical barrel showing KIH packing for the buttressing helices (shaded red) and the inner barrel (shaded blue): red, a sites; green, d sites; magenta, g sites; and cyan, e sites; N and C labels refer to the termini of the helices closest to the viewer. b, Sequence pileups and registers for the inner (blue register) and buttressing (red register) helices of sc-CC-7-LI. c,d, Circular dichroism spectrum recorded at 5 °C (c) and thermal-response curve (d) for sc-CC-7-LI. e, AUC sedimentation velocity data for sc-CC-7-LI fitted to a single-species model, which returned MW = 37.4 kDa (monomer). f, Fitted binding data of DPH to sc-CC-7-LI, which returned Kd = 3.8 ± 0.8 µM. Fitted data are the mean and s.d. of three independent repeats. g, SEC-SAXS data fitted using the final AlphaFold2 model and FoXS (χ² = 1.43)57,58. h, X-ray crystal structure of sc-CC-7-LI at a 2.5-Å resolution (PDB ID, 8QAI). Coiled-coil regions identified by Socket2 (ref. ⁷²) (packing cutoff, 7 Å) are colored as chainbows from N termini to C termini (blue to red). i, A slice through the structure of a heptad repeat showing KIH packing with a-type (red) and d-type (green) knobs. j, Overlay of the middle helical turns from the sc-CC-7-LI structure (cyan) and the final AlphaFold2 model (magenta) (RMSDbb = 0.433 Å). The conditions were as follows: circular dichroism spectroscopy, 5 µM protein in PBS, pH 7.4; AUC, 25 µM protein in PBS, pH 7.4; DPH binding, 0–24 µM protein in PBS, pH 7.4, final concentration was 0.5 µM DPH (5% v/v DMSO); SEC-SAXS, 10 mg ml⁻¹ protein in PBS, pH 7.4.
Source data
Structural characterization of five-helix, six-helix and eight-helix targets
a–d, Top, X-ray crystal structures of sc-apCC-8 at a 2.0-Å resolution (PDB ID, 8QAF) (a), sc-CC-5 at a 1.9-Å resolution (PDB ID, 8QKD) (b), sc-CC-6-95 at a 2.8-Å resolution (PDB ID, 8QAG) (c) and sc-CC-8-58 at a 2.35-Å resolution (PDB ID, 8QAH) (d). Coiled-coil regions identified by Socket2 (ref. ⁷²) (packing cutoff, 7.5 Å for sc-apCC-8, sc-CC-5-24, sc-CC-6-95 and sc-CC-8-58 at 7.0 Å) are colored as chainbows from N termini (blue) to C termini (red). Bottom, overlays for the middle helical turns of each crystal structure (cyan) and the corresponding AlphaFold2 (refs. 55,56) model (magenta); RMSDbb = 0.413 Å (a), RMSDbb = 0.371 Å (b), RMSDbb = 0.300 Å (c) and RMSDbb = 0.530 Å (d).
Source data
Comparison of de novo α-helical barrel proteins against existing and predicted protein folds
Foldseek⁶⁶ was used for this comparison. Each de novo α-helical barrel protein structure determined in this study (cyan) is overlaid with the top match from the AlphaFold2–Swiss-Prot database,55,69 and natural and de novo sequences from the PDB67,68 (red). Within each box, the top value is the ID of the matched structure, the middle value is the backbone RMSD between the query and match, and the bottom value is the template modeling score⁷⁰ between the two structures.
Source data
Rationally seeded computational protein design of ɑ-helical barrels

June 2024

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93 Reads

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8 Citations

Nature Chemical Biology

Computational protein design is advancing rapidly. Here we describe efficient routes starting from validated parallel and antiparallel peptide assemblies to design two families of α-helical barrel proteins with central channels that bind small molecules. Computational designs are seeded by the sequences and structures of defined de novo oligomeric barrel-forming peptides, and adjacent helices are connected by loop building. For targets with antiparallel helices, short loops are sufficient. However, targets with parallel helices require longer connectors; namely, an outer layer of helix–turn–helix–turn–helix motifs that are packed onto the barrels. Throughout these computational pipelines, residues that define open states of the barrels are maintained. This minimizes sequence sampling, accelerating the design process. For each of six targets, just two to six synthetic genes are made for expression in Escherichia coli. On average, 70% of these genes express to give soluble monomeric proteins that are fully characterized, including high-resolution structures for most targets that match the design models with high accuracy.


Strong coupling in molecular systems: a simple predictor employing routine optical measurements

April 2024

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130 Reads

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2 Citations

We provide a simple method that enables readily acquired experimental data to be used to predict whether or not a candidate molecular material may exhibit strong coupling. Specifically, we explore the relationship between the hybrid molecular/photonic (polaritonic) states and the bulk optical response of the molecular material. For a given material, this approach enables a prediction of the maximum extent of strong coupling (vacuum Rabi splitting), irrespective of the nature of the confined light field. We provide formulae for the upper limit of the splitting in terms of the molar absorption coefficient, the attenuation coefficient, the extinction coefficient (imaginary part of the refractive index) and the absorbance. To illustrate this approach, we provide a number of examples, and we also discuss some of the limitations of our approach.


Chlorophyll Binding to Poly(cysteine methacrylate) Scaffolds in Pigment-Polymer Antenna Complexes studied by Depth-Profiling X-Ray Photoelectron Spectroscopy with a Gas Cluster Ion Source

April 2024

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15 Reads

X-ray photoelectron spectroscopy (XPS) depth-profiling with an argon gas cluster ion source (GCIS) was used to characterize the spatial distribution of chlorophyll a (Chl) within a poly(cysteine methacrylate) (PCysMA) brush grown by surface-initiated atom-transfer radical polymerization (ATRP) from a planar surface. The organization of Chl is controlled by adjusting the brush grafting density and polymerization time. For dense brushes, the C, N, S elemental composition remains constant throughout the 36 nm brush layer until the underlying gold substrate is approached. However, for either reduced density brushes (mean thickness 20 nm) or mushrooms grown with reduced grafting densities (mean thickness 6-9 nm), elemental intensities decrease continuously throughout the brush layer, because photoelectrons are less strongly attenuated for such systems. For all brushes, the fraction of positively charged nitrogen atoms (N+/N0) decreases with increasing depth. Chl binding causes a marked reduction in N+/N0 within the brushes and yields a new feature at 398.1 eV in the N1s spectrum assigned to tetrapyrrole ring nitrogen atoms coordinated to Zn2+. For all grafting densities, the N/S ratio remains approximately constant as a function of brush depth, which indicates a uniform distribution of Chl throughout the brush layer. However, a larger fraction of repeat units bound to Chl is observed at lower grafting densities, reflecting a progressive reduction in steric congestion that enables more uniform distribution of the bulky Chl units throughout the brush layer. In summary, XPS depth-profiling using a GCIS is a powerful tool for characterization of these complex materials.


Citations (76)


... 41 Moreover, recently, we have shown that the αHB peptide assemblies can be converted to thermostable single-chain proteins by linking multiple helices together through computational protein design. 49 These single-chain proteins are produced by expression from synthetic genes, which opens possibilities for desymmetrization and functionalization through further rational computational protein design, and to improve activity using directed evolution. 6,50 Thus, the αHB peptides and proteins offer an exciting platform for combining the shape complementarity and confinement offered by organic molecular flasks with the diversity of binding-site geometries and substrate selectivity seen in natural enzymes. ...

Reference:

Confinement and Catalysis within De Novo Designed Peptide Barrels
Rationally seeded computational protein design of ɑ-helical barrels

Nature Chemical Biology

... In particular, Rider et al. [20] show us how using molecular absorption properties one can screen for materials that are guaranteed to showcase large Rabi splittings. Schwennicke and Yuen-Zhou [21] use it to provide a prescription to extract collective coupling intensities from disordered ensembles (a ubiquitous scenario in molecular materials) given information from linear absorption, reflection, and transmission spectra. ...

Strong coupling in molecular systems: a simple predictor employing routine optical measurements

... In addition to neutral polymer brushes, it is also possible to have charged polymer brushes, and the study of the brush-particle interactions in these systems has also received some attention. For instance, the controlled adsorption of nanoparticles on polyelectrolyte brushes via pH has been addressed by Astier et al. [88]. Furthermore, Popova et al. [89] using mean-field Poisson-Boltzmann approximation, have shown that a charged brush uptakes the nanoparticles when the interaction between the brush and the particle promotes changes in the ionization state of the weak cationic and anionic groups on the surface of the nanoparticle. ...

Controlling Adsorption of Diblock Copolymer Nanoparticles onto an Aldehyde-Functionalized Hydrophilic Polymer Brush via pH Modulation

Langmuir

... The high-quality (Q) optical modes are advantageous for a variety of on-chip applications, like sensing [1], optical filtering [2], nonlinear optics [3], light absorption [4] and emission, etc [5,6]. Bound states in the continuum (BICs) are localized modes with infinite Q factor in the radiating continuum regime. ...

Engineering and Controlling Perovskite Emissions via Optical Quasi‐Bound‐States‐in‐the‐Continuum

... Indeed, protein design has largely sought to maximize the free energy difference between a single, desired, folded structure and the unfolded and alternative states. In this respect, the state of the art of protein design is impressive, as defined single states are increasingly being delivered with high accuracy [4][5][6][7] . However, many of these are hyperstable [8][9][10][11] , probably less dynamic than natural protein structures, and thus are limited for exploring conformational dynamics, alternative states and allostery. ...

Rationally seeded computational protein design

... Scientists generally use this post-synthetic polymer grafting strategy to increase the characteristics of the MOF. These alterations stimulate the dynamic responses in numerous biological applications yet depend on active ligands and limit specific applications [55]. Moreover, research on the ways in which the alteration of polymer characteristics influences the performance of MOFs also remains limited [56]. ...

Adsorption of Aldehyde-Functional Diblock Copolymer Spheres onto Surface-Grafted Polymer Brushes via Dynamic Covalent Chemistry Enables Friction Modification

Chemistry of Materials

... After the plasma activations and consequent insertions of oxygen-containing groups, most of the surface properties are affected, including the resulting ζ-potential [72]. The To better inspect the effect of the plasma activation on the film surfaces, we record the ζ-potential-pH curves, a technique widely used to investigate differences obtained after oxidation of materials surfaces [70]. ...

Hydrophilic Aldehyde-Functional Polymer Brushes: Synthesis, Characterization, and Potential Bioapplications

Macromolecules

... Biomimetic synthesis is a green and environmentally friendly strategy for the preparation of various functional nanomaterials, which can promote the formation of nanomaterials with desired shapes and functions through simulating the unique materials, structures, and functions in natural things. 1 Compared with other chemical and physical synthetic methods, biomimetic synthesis usually does not require redundant ligands, solvents, and reducing/oxidizing agents and can realize the synthesis and applications of nanomaterials under mild conditions with the assistance of biological substances. 2 Previous studies have indicated that the biomimetic synthesis of metal nanoparticles (NPs) can be realized by some methods, including templated synthesis, seedmediated synthesis, biomineralization, biometallization, and target anchoring. [3][4][5][6][7][8][9][10] For instance, Ruan et al. reported the synthesis of platinum nanoparticles (PtNPs) with peptide templates, which can further be used as nucleation sites for the formation of Pt nanowires at room temperature without the use of additional reagents. The reaction conditions were mild and controllable. ...

Active control of strong plasmon–exciton coupling in biomimetic pigment–polymer antenna complexes grown by surface-initiated polymerisation from gold nanostructures

... Such open cavity has an easy access to the volume in which an emitter can be placed. Plasmonic-photonic cavities that are able to support energy exchange in the strong coupling regime are promising for thresholdless nanolasers [6,7], ultra-sensitive optical sensing [8,9], modification of chemical reaction rates [10][11][12] and quantum information processing [13]. The strong coupling regime is achieved when energy exchange between the light-like mode (plasmonic resonance) and the matter like emitters (organic dye molecules) occurs during the coherent time [14]. ...

Turning the Challenge of Quantum Biology On its Head Biological Control of Quantum Optical Systems

Faraday Discussions

... 23 The diffusion of poly(ethylene oxide) (PEO) on surfaces is a function of other parameters such as the concentration of adsorbed polymer [24][25][26][27] or the presence of topographic constraints. 28,29 All of these experiments concern the diffusion at the solid-liquid interface. Little is known of how a polymer diffuses at the aqueous interface with a molten polymer film, which is subject to capillary waves, which themselves are influenced by the surface melting associated with the glass transition. ...

Slow polymer diffusion on brush-patterned surfaces in aqueous solution
  • Citing Article
  • March 2019

Nanoscale