Complex Nanoarchitectures Research Articles

Use of a novel proteomimetic nanoplatform for simultaneous delivery of antigens with adjuvants to impact tumor growth in multiple tumor models.

40 Background: Patient-specific cancer vaccines derived from tumor antigen have been explored as a promising therapeutic strategy, however, challenges delivering vaccine components in a coordinated fashion to elicit antitumor responses remain. To overcome these, we utilize a novel nanoplatform called the Protein-Like Polymer (PLP), which allows for sustained and targeted delivery of tumor antigens in conjunction with adjuvants. Methods: PLPs containing peptide antigens were synthesized via ROMP and characterized. A library of compounds with different sidechain linkage chemistries, degrees of polymerization (DP), and inclusion/exclusion of Oligo-ethylene glycol (OEG) were made to determine design rules for immune activation. Cell uptake and functional assays using payload-specific T Cells were conducted. Immunization in three independent tumor models was done to show generalizability. Ability of PLPs to co-deliver adjuvants was tested by electrostatically coupling small molecule STING agonist, 2’3’ cGAMP. Results: Conjugating antigens to the polymer via a cleavable disulfide linkage, which reduces intracellularly in APCs, resulted in increased endosomal localization, higher levels of induced T cell proliferation, cytokine production, and expression of activation markers in CTLs and APCs. Incorporating a diluent amount of OEG side chains reduced enzymatic degradation while increasing immunogenicity and uptake. Additionally, increasing the DP, and therefore the density of antigen side chains, further improved vaccine efficacy and resistance to proteolysis. Antigen-PLP conjugates enhanced dendritic cell activation and T-cell response only when paired with cells from their cognate system, with no activity in immune cells not expressing receptors for the payload demonstrating antigen-specificity. Mice bearing established B16F10, MC38, or TC-1 tumors treated with PLPs containing gp100, adpgk, or E7 respectively all showed increased survival times, reduced tumor burden with corresponding changes in immune cell profiles, and immunological memory upon rechallenge. Impressively, mice treated with STING-PLP complexes had significantly smaller tumors vs control at day 14 (0.038g vs 0.76g; p < 0.0001) and allowed for subcutaneous administration of 2’3’ cGAMP, which traditionally requires intratumoral injection. Studies on the effects of vaccinating with pools of neoantigens multiplexed onto one PLP are ongoing. Conclusions: This work validates the ability of PLPs to overcome major limitations in cancer vaccine development. The modularity of the platform allows for complex nano-architectures including systems capable of delivering challenging compounds, ie small molecule STING agonists, subcutaneously through electrostatic coupling, highlighting its potential to revolutionize cancer vaccinology.

Topology Selectivity of a Conformationally Flexible Precursor by Selenium Doping

Conformational arrangements within nanostructures play a crucial role in shaping the overall configuration and determining the properties, for example in covalent/metal organic framework (COF/MOF) synthesis. In on-surface synthesis, conformational diversity often leads to uncontrollable or disordered structures. Therefore, exploration on controlling and directing the conformational arrangements is significant in achieving desired nanoarchitectures. In this study, a conformationally flexible precursor 2,4,6-tris(3-bromophenyl)-1,3,5-triazine (mTBPT) was employed, and a random phase consisting of C3h and Cs conformers was first obtained after deposition of mTBPT on Cu(111) from room temperature (RT) to ~365 K as expected. By low coverage (0.01 ML) selenium (Se) doping, we achieved the selectivity of the C3h conformer greatly and improved the nanopore structural homogeneity. The ordered 2D metal organic nanostructure from mTBPT could be fulfilled by Se doping from RT to ~365 K, and the deposition sequence of mTBPT and Se did not make any difference. Through the combination of high-resolution scanning tunneling microscopy and non-contact atomic force microscopy, we explored the regulation of the conformationally flexible mTBPT on Cu(111) and achieved the high topology selectivity by low coverage Se doping. Density functional theory calculations revealed the energy regulation of organometallics before and after Se doping at atomic level. These results could enrich the on-surface synthesis toolbox of conformationally flexible precursors, for the design of complex nanoarchitectures, and for future development of engineered nanomaterials and nanodevices. Figure 1

Topology selectivity of a conformationally flexible precursor through selenium doping

Conformational arrangements within nanostructures play a crucial role in shaping the overall configuration and determining the properties, for example in covalent/metal organic frameworks. In on-surface synthesis, conformational diversity often leads to uncontrollable or disordered structures. Therefore, the exploration of controlling and directing the conformational arrangements is significant in achieving desired nanoarchitectures. Herein, a conformationally flexible precursor 2,4,6-tris(3-bromophenyl)−1,3,5-triazine is employed, and a random phase consisting of C3h and Cs conformers is firstly obtained after deposition of the precursor on Cu(111) at room temperature to 365 K. At low coverage (0.01 ML) selenium doping, we achieve the selectivity of the C3h conformer and improve the nanopore structural homogeneity. The ordered two-dimensional metal organic nanostructure can be fulfilled by selenium doping from room temperature to 365 K. The formation of the conformationally flexible precursor on Cu(111) is explored through the combination of high-resolution scanning tunneling microscopy and non-contact atomic force microscopy. The regulation of energy diagrams in the absence or presence of the Se atom is revealed by density functional theory calculations. These results can enrich the on-surface synthesis toolbox of conformationally flexible precursors, for the design of complex nanoarchitectures, and for future development of engineered nanomaterials.

Abstract 481: Proteomimetic polymers limit tumor growth in multiple models via potent antigen-specific T cell activation

Abstract Background: Patient-specific cancer vaccines derived from tumor antigen have been explored as a promising therapeutic strategy, however, challenges delivering vaccine components in a coordinated fashion to elicit antitumor responses remain. To overcome these, we utilize a novel nanoplatform called the Protein-Like Polymer (PLP), which allows for sustained and targeted delivery of tumor antigens in conjunction with adjuvants. Methods: PLPs containing peptide antigens were synthesized via ring-opening metathesis polymerization (ROMP) and characterized. A library of compounds with different sidechain linkage chemistries, degrees of polymerization (DP), and inclusion/exclusion of Oligo-ethylene glycol (OEG) were made to determine design rules for immune activation. Cell uptake and functional assays using payload-specific T Cells were conducted. Immunization in three independent tumor models was done to show generalizability. Ability of PLPs to co-deliver adjuvants was tested by electrostatically coupling small molecule STING agonist, 2’3’ cGAMP. Results: Conjugating peptide antigens to the polymer via a cleavable disulfide linkage, which reduces intracellularly in APCs, resulted in increased endosomal localization, higher levels of induced T cell proliferation, cytokine production, and expression of activation markers in CTLs and APCs. Incorporating a diluent amount of OEG side chains reduced enzymatic degradation while increasing immunogenicity and uptake. Additionally, increasing the DP, and therefore the density of antigen side chains, further improved vaccine efficacy and resistance to proteolysis. Antigen-PLP conjugates enhanced dendritic cell activation and T-cell response only when paired with cells from their cognate system, with no activity in immune cells not expressing receptors for the payload demonstrating antigen-specificity. Mice bearing established B16F10, MC38, or TC-1 tumors treated with PLPs containing gp100, adpgk, or E7 respectively all showed increased survival times, reduced tumor burden with corresponding changes in immune cell profiles, and immunological memory upon rechallenge. Impressively, mice treated with STING-PLP complexes had significantly smaller tumors vs control at day 14 (0.038g vs 0.76g; p <0.0001) and allowed for subcutaneous administration of 2’3’ cGAMP, which traditionally requires intratumoral injection. Studies on the effects of vaccinating with pools of neoantigens multiplexed onto one PLP are ongoing. Conclusion: This work validates the ability of PLPs to overcome major limitations in cancer vaccine development. The modularity of the platform allows for complex nano-architectures including systems capable of delivering challenging compounds, ie small molecule STING agonists, subcutaneously through electrostatic coupling, highlighting its potential to revolutionize cancer vaccinology. Citation Format: Max Wang, Miran Choi, Bin Zhang, Nathan Gianneschi. Proteomimetic polymers limit tumor growth in multiple models via potent antigen-specific T cell activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 481.

Discriminating macromolecular interactions based on an impedimetric fingerprint supported by multivariate data analysis for rapid and label-free Escherichia coli recognition in human urine

This manuscript presents a novel approach to address the challenges of electrode fouling and highly complex electrode nanoarchitecture, which are primary concerns for biosensors operating in real environments. The proposed approach utilizes multiparametric impedance discriminant analysis (MIDA) to obtain a fingerprint of the macromolecular interactions on flat glassy carbon surfaces, achieved through self-organized, drop-cast, receptor-functionalized Au nanocube (AuNC) patterns. Real-time monitoring is combined with singular value decomposition and partial least squares discriminant analysis, which enables selective identification of the analyte from raw impedance data, without the use of electric equivalent circuits. As a proof-of-concept, the authors demonstrate the ability to detect Escherichia coli in real human urine using an aptamer-based biosensor that targets RNA polymerase. This is significant, as uropathogenic E. coli is a difficult-to-treat pathogen that is responsible for the majority of hospital-acquired urinary tract infection cases. The proposed approach offers a limit of detection of 11.3 CFU/mL for the uropathogenic E. coli strain No. 57, an analytical range in all studied concentrations (up to 105 CFU/mL), without the use of antifouling strategies, yet not being specific vs other E.coli strain studied (BL21(DE3)). The MIDA approach allowed to identify negative overpotentials (−0.35 to −0.10 V vs Ag/AgCl) as most suitable for the analysis, offering over 80% sensitivity and accuracy, and the measurement was carried out in just 2 min. Moreover, this approach is scalable and can be applied to other biosensor platforms.

Use of proteomimetic polymers for delivery of tumor antigens and adjuvants through formation of stable electrostatic complexes with small molecule STING agonists.

2583 Background: Utilizing tumor antigens for the development of patient-specific cancer vaccines has been a promising therapeutic strategy. However, significant challenges remain in delivering subunit vaccine components to elicit antitumor immune responses. To overcome these, we developed rationally designed cancer vaccines using a new nanoplatform called the Protein-Like Polymer (PLP) with unique characteristics that allow for sustained delivery of tumor antigens in conjunction with immunomodulatory compounds. Methods: PLPs containing antigens were synthesized via ring-opening metathesis polymerization (ROMP) and characterized using HPLC, LC-MS, NMR, and GPC. A library of compounds were generated with different sidechain linkage chemistries (amide, ester, or disulfide linkage), DPs, and inclusion of PEG side chains. In vitro assays using gp100-specific T Cells were conducted with fluorescently labeled and non-labeled polymers. In vivo experiments were done using B16 murine melanoma transplanted tumor models. Ability of PLPs to co-deliver immunomodulatory compounds was tested using a small molecule STING agonist 2’3’ cGAMP. Results: Conjugating antigens to the polymer backbone using a cleavable disulfide linkage, designed to be reduced intracellularly, resulted in the best subcellular localization and immune activation (higher levels of immune cell proliferation, cytokine production, and expression of activation markers). Incorporating a diluent amount of PEG side chains increased resistance to enzymatic degradation while improving bioactivity and cell uptake. In vivo studies using PLPs conjugated with melanoma-associated antigen gp100 showed the reductions in tumor size with increased immune cell proliferation and activation in a B16 melanoma model. Additionally, increasing the degree of polymerization, and therefore the density of antigen side chains per unit polymer, improved vaccine efficacy and resistance to proteolysis. Mice treated with STING agonists electrostatically coupled to PLPs showed significantly smaller tumors vs no-treatment at day 14 (0.038g vs 0.76g; p <0.0001) and allowed for subcutaneous administration of the small molecule, which normally must be injected intratumorally. Conclusions: Our work demonstrates the potential of PLPs to overcome inherent difficulties associated with developing cancer vaccines. The modularity of the platform allows for complex nano-architectures including systems capable of delivering challenging compounds, ie small molecule STING agonists, subcutaneously through electrostatic coupling. This technology has the potential to revolutionize cancer vaccinology.

Design and Optimization of a Novel Proteomimetic Polymer Nanoplatform for the Co-delivery of Antigens with Adjuvants

Abstract We describe here a novel nanoplatform called the Protein-Like Polymer (PLP) with unique characteristics allowing for sustained delivery of tumor antigens in conjunction with STING agonists. Methods: A library of PLP formulations were synthesized via ROMP and characterized. Cell uptake/functional assays were conducted with payload-specific T Cells. Ability of PLPs to co-deliver adjuvants was tested by electrostatically coupling 2′3′ cGAMP, forming stable nanostructures. Results: Conjugating antigens to the polymer backbone using a cleavable disulfide linkage (reduces in APCs) resulted in increased endosomal localization and T cell proliferation/activation. Incorporating OEG side chains reduced enzymatic degradation while increasing immunogenicity and APC uptake. Increasing the density of side chains further improved vaccine efficacy and resistance to proteolysis. Antigen-PLP conjugates is effective only when paired with cells from their cognate system, demonstrating payload-specificity. Mice bearing established B16F10 tumors treated with gp100-PLPs resulted in increased survival time and reduced tumor burden with corresponding changes in immune cell profiles. Notably, STING-PLP complexes showed significantly smaller tumors at day 14 and allowed for subcutaneous administration of 2′3′ cGAMP. Studies looking at multiplexing pools of neoantigens onto one PLP and generation of immunological memory are ongoing. Conclusion: The modularity of the PLP platform allows for complex nano-architectures including systems capable of delivering challenging compounds, ie small molecule STING agonists, subcutaneously through electrostatic coupling, highlighting its potential to revolutionize cancer vaccinology. Supported by grants from the NIH (5F30CA257519-03)

Controlled Morphological Bending of 3D-FEBID Structures via Electron Beam Curing

Focused electron beam induced deposition (FEBID) is one of the few additive, direct-write manufacturing techniques capable of depositing complex 3D nanostructures. In this work, we explore post-growth electron beam curing (EBC) of such platinum-based FEBID deposits, where free-standing, sheet-like elements were deformed in a targeted manner by local irradiation without precursor gas present. This process diminishes the volumes of exposed regions and alters nano-grain sizes, which was comprehensively characterized by SEM, TEM and AFM and complemented by Monte Carlo simulations. For obtaining controlled and reproducible conditions for smooth, stable morphological bending, a wide range of parameters were varied, which will here be presented as a first step towards using local EBC as a tool to realize even more complex nano-architectures, beyond current 3D-FEBID capabilities, such as overhanging structures. We thereby open up a new prospect for future applications in research and development that could even be further developed towards functional imprinting.

A novel polymeric peptide delivery platform and association with targeted co-delivery of antigens and STING agonists with antitumor immune response.

2564 Background: Use of tumor antigens for the development of patient-specific cancer vaccines has been a promising therapeutic strategy. However, challenges remain in delivering subunit vaccine components in a coordinated fashion to elicit antitumor immune responses. To overcome these, we developed rationally designed vaccines using a novel nanoplatform called the Protein-Like Polymer (PLP), in reference to its globular structure reminiscent of native proteins, with unique characteristics that allow for sustained/targeted delivery of tumor antigens in conjunction with STING agonists. Methods: PLPs containing a model melanoma antigen were synthesized via ring-opening metathesis polymerization (ROMP) and characterized. A library of compounds were generated with different sidechain linkage chemistries (amide, ester, or disulfide), degrees of polymerization, and inclusion/exclusion of Oligo(ethylene glycol) (OEG) side chains. In vitro uptake and functional assays using gp100-specific T Cells were conducted with fluorescently-labeled and non-labeled polymers respectively. In vivo experiments were done using a B16F10 murine melanoma tumor model over-expressing gp100. Ability of PLPs to co-deliver immunomodulatory compounds was tested by electrostatically coupling a small molecule STING agonist 2’3’ cGAMP which formed stable nanostructures. The optimized construct was also tested in an OVA system to prove generalizability. Results: Conjugating peptide antigens using a cleavable disulfide linkage, which reduces intracellularly in antigen presenting cells (APCs), resulted in increased endosomal localization and efficacy. Incorporating a diluent amount of OEG side chains increased resistance to enzymatic degradation while improving bioactivity and uptake by APCs. In vivo studies using PLPs conjugated with gp100 resulted in significant increases in survival time and reduced tumor burden in B16 melanoma. Increasing the DP, and therefore the density of antigen side chains, improved vaccine efficacy and resistance to proteolysis. Mice treated with STING-PLP complexes showed significantly smaller tumors vs control at day 14 (0.038g vs 0.76g; p < 0.0001) and allowed for subcutaneous administration of 2’3’ cGAMP, which otherwise diffuses rapidly away from the injection site. OVA-PLPs behaved similarly in their cognate system but showed no activity when tested on gp100-specific cells and vice versa demonstrating antigen-specificity. Conclusions: This work validates the potential of PLPs to overcome major limitations in cancer vaccine development. The modularity of the platform allows for complex nano-architectures including systems capable of delivering challenging compounds, ie small molecule STING agonists, subcutaneously through electrostatic coupling. This technology has the potential to revolutionize cancer vaccinology.

Increasing the structural and compositional diversity of ion-track templated 1D nanostructures through multistep etching, plastic deformation, and deposition

Ion-track etching represents a highly versatile way of introducing artificial pores with diameters down into the nm-regime into polymers, which offers considerable synthetic flexibility in template-assisted nanofabrication schemes. While the mechanistic foundations of ion-track technology are well understood, its potential for creating structurally and compositionally complex nano-architectures is far from being fully tapped. In this study, we showcase different strategies to expand the synthetic repertoire of ion-track membrane templating by creating several new 1D nanostructures, namely metal nanotubes of elliptical cross-section, funnel-shaped nanotubes optionally overcoated with titania or nickel nanospike layers, and concentrical as well as stacked metal nanotube-nanowire heterostructures. These nano-architectures are obtained solely by applying different wet-chemical deposition methods (electroless plating, electrodeposition, and chemical bath deposition) to ion-track etched polycarbonate templates, whose pore geometry is modified through plastic deformation, consecutive etching steps under differing conditions, and etching steps intermitted by spatially confined deposition, providing new motifs for nanoscale replication.

Tracking the Evolution of Metastasis with Self-Functionalized 3D Nanoprobes.

Despite recent advances in cancer treatment, metastasis is the cause of mortality in 90% of cancer cases. It has now been well-established that dissemination of cancer cells to distant sites occurs very early during tumorigenesis, resulting in the minimal effect of surgical or chemotherapeutic treatments after the detection of metastasis. The underlying reason for this challenge is mostly due to the limited understanding of molecular mechanisms of the metastasis cascade, particularly related to metastatic traits. Therefore, there is an urgent need to investigate this currently invisible evolution of metastasis. The tracking of metastasis evolution has not been addressed yet. Here, we introduce, for the first time, a synchronous approach to unveil the molecular mechanisms of the metastasis cascade. As cancer stem cells (CSCs) demonstrate cancer initiation, drug resistance, metastasis, and tumor relapse and can exist in a quasi-intermediate epithelial-mesenchymal transition state, the tumor-initiating events during a CSCs metamorphosis were monitored with single-cell sensitivity. Because of the invasive and resistive properties of the metastable intermediate CSCs, investigation of the molecular profiles of the quasi-intermediate CSCs was necessary for the detection of metastasis dissemination. For this purpose, the ultrasensitive technique of surface-enhanced Raman scattering (SERS) was adopted. Titanium-based, biocompatible three-dimensional (3D) nanoprobes that were synthesized for multiphoton ionization achieved a substantial SERS enhancement of ∼80-fold due to the oxygen vacancy-enriched composition of the nanoprobes. The 3D interconnected complex nanoarchitecture of the nanoprobes enabled us to entrap the nonadherent CSCs of three metastatic cancer cell lines (triple negative breast adenocarcinoma (MDAMB231), human Caucasian colon adenocarcinoma (COLO 205), and cervical adenocarcinoma (HeLa)─all very aggressive forms of cancer). The nanoprobes not only promoted the CSC proliferation to successfully attain the quasi-intermediate states but also monitored its reprogramming into a cancer cell state. The nanoprobes substantially amplified weak intracellular Raman signals to capture the molecular events during a CSC transformation. The detection of cancer was achieved with 100% accuracy. We experimentally demonstrated that the molecular signatures of CSC reprogramming are cancer-type specific. This observation enabled us to identify the origin of metastasis with 100% accuracy, providing more clarity on the relatively unknown quasi-intermediate states. This first demonstration of CSC-based tracking of metastasis evolution has the potential to provide an insightful perspective of tumorigenesis that could be useful in cancer diagnosis and prognosis as well as in the monitoring of therapeutic interventions.

Expanding FEBID-Based 3D-Nanoprinting toward Closed High-Fidelity Nanoarchitectures

3D-nanoprinting via focused electron beam induced deposition (FEBID) is a highly flexible additive-fabrication technique that has gained importance in the past few years for its variable design possibilities on the micro and nanoscale. In this work, we show the transition from mesh-like toward closed (sheet-like) structures and the development of necessary compensations (height correction, temperature compensation, and proximity correction) to minimize deviations between the target structure and the actual deposit. To accomplish this, we investigate the growth behavior, the influence of beam heating, and the electron trajectories in extensive experimental series as well as finite-difference simulations. Out of this, we derive a modular Python tool taking all compensations into account, enabling the controlled and accurate deposition of 3D-nanostructures in an individually adjusted layer-by-layer approach. This approach forms the basis for accurately fabricating closed, sheet-like objects on the nanoscale and lays the foundation for depositing complex nanoarchitectures for various applications in research and development.

A microfluidic approach for synthesis and kinetic profiling of branched gold nanostructures.

Automatized approaches for nanoparticle synthesis and characterization represent a great asset to their applicability in the biomedical field by improving reproducibility and standardization, which help to meet the selection criteria of regulatory authorities. The scaled-up production of nanoparticles with carefully defined characteristics, including intrinsic morphological features, and minimal intra-batch, batch-to-batch, and operator variability, is an urgent requirement to elevate nanotechnology towards more trustable biological and technological applications. In this work, microfluidic approaches were employed to achieve fast mixing and good reproducibility in synthesizing a variety of gold nanostructures. The microfluidic setup allowed exploiting spatial resolution to investigate the growth evolution of the complex nanoarchitectures. By physically isolating intermediate reaction fractions, we performed an advanced characterization of the shape properties during their growth, not possible with routine characterization methods. Employing an in-house developed method to assign a specific identity to shapes, we followed the particle growth/deformation process and identified key reaction parameters for more precise control of the generated morphologies. Besides, this investigation led to the optimization of a one-pot multi-size and multi-shape synthesis of a variety of gold nanoparticles. In summary, we describe an optimized platform for highly controlled synthesis and a novel approach for the mechanistic study of shape-evolving nanomaterials.

A Review of the State of the Art towards Biological Applications of Graphene-based Nanomaterials

The field of nanoscience has evolved into a wide variety of successes over the past two decades and the emphasis on nanotechnology is to revolve around various dynamic fields, such as sensor, biomedical, and many useful applications. Advances in related fields are certainly due to the ability to synthesize nanoparticles from a variety of materials, structures, and to convert samples into complex nanoarchitectures. The promises of nanomedicine are broad. Graphene (Gr), the first 2-dimensional material to stand alone, is a type of new nanomaterial that leads to the excitement of natural biological applications. Number of researches has been conducted on applicability of GBNs in the area of environment, biomedical, and healthcare sectors. As compared to other nanomaterials, extraordinary properties of graphene-based nanomaterials (GBNs) like high surface area, multilayers, multifunctional and excellent biocompatibility make them capable to play great roll of highly-tailored multifunctional delivery vehicles for drugs delivery, gene delivery, phototherapy and bioimaging. However, research communities performed plenty of research works on GBNs synthesis and biological acitivity evaluation, but there is limited comprehensive reviews published so far biological applications. So, we have studied a large number of scientific reports and investigations, presented in this review describing recent progress and modern perspectives with respect to graphene and related nanomaterials for biological applications.

(Invited) The Role of Surface Inhibition in Deterministic Controlled Electrodeposition

Templated electrodeposition is a common practice for the fabrication of metal nanostructures. The nanostructure architecture is set by that of the nanoporous template. For complex nano-architectures such as the metal nanomesh (see Figure) which was developed in our group [1,2], templates will remain necessary. Nonetheless, the 3D nanoporous anodized aluminum oxide (AAO) used for the templated electrodeposition, did form by self-assembly. Regular AAO made from pure Al has only vertical pores with a hexagonal arrangement. The additional horizontal pores in the 3D-AAO are formed with regular interval by doping of the aluminum with Cu [1]. Such level of deterministic control on the growth direction is not yet achievable with electrodeposition. Yet, directed growth of pillars and nanowires has been achieved by control of current inhibiting surface layers, either introduced by additives [3] or intrinsic to the metal electrochemistry [4]. We will shortly discuss the example of indium electrodeposition where InCl intermediate adsorbate is believed to form a coating around electrodeposited indium, leading to large single crystalline morphologies and nanowires when guided by a shallow pattern [3].Conformal deposition of thin-film coatings on high aspect ratio structures is typically claimed by Atomic and Molecular Layer Deposition (ALD and MLD). The nature of the surface limited reactions of these vapor-phase methods allows for the formation of continuous sub-nanometer to a few tens of nanometer thin films with uniform thickness over the most complex architectures. The accuracy of the technique goes at the cost of long deposition cycles especially when very large surface areas with extreme aspect ratios (>100) are involved. In recent years, electrodeposition processes have shown where the metal electrodeposition reaction for e.g. Ni or Pt can be inhibited early on, similarly leading to sub-nanometer to few nanometer thick coatings by cycling [5, 6]. In this paper, we will show examples where this process can be used also to coat nano-architectures such as our nanomesh with very large surface area (100 cm2 per planar cm2) and aspect ratio (100x).Finally, the electrochemical fabrication of oxide thin-films by electro-precipitation and electrochemically induced sol-gel reactions will be discussed. The poor electronic conductivity of oxides makes that the reaction is maintained by ionic conduction through the films, similar as for oxide formation by anodization. The resistive nature of the layers typically allows also for good conformality over high aspect ratio substrates [7]. Similarly, thin polymer films such as poly-phenylene oxide or PPO can be made conformally [8].[1] "The Formation Mechanism of 3D Porous Anodized Aluminum Oxide Templates from an Aluminum Film with Copper Impurities" Johannes Vanpaemel, Alaa Abd-Elnaiem, Stefan De Gendt, Philippe M. Vereecken, J. Phys. Chem. C, 119 (4), 2105–2112 (2015); [2] “Combining High Porosity with High Surface Area in Flexible Interconnected Nanowire Meshes for Hydrogen Generation and Beyond" Stanislaw Zankowski and Philippe M. Vereecken, ACS Appl. Mater. Interfaces, 10 (51), pp 44634–44644 (2018); [3] “Electrodeposited free-standing single-crystal indium nanowires" G. Hautier, J. D’Haen, K. Maex and P.M. Vereecken, ESL 11, K49 (2008); [4] “Fabrication of complex architectures using electrodeposition into patterned self-assembled monolayers” N.S.Pesika, A. Radisic, K.J. Stebe, P.C. Searson, Nano Letters. 6, 1023-1026 (2006); [5] Electro-chemical deposition of sub-nanometer Ni films on TiN” Johannes Vanpaemel, Masahito Sugiura ,Daniel Cuypers, Marleen H. van der Veen, Stefan De Gendt, Stefan and Philippe M. Vereecken, Langmuir, 30 (8), 2047–2053 (2014); [6] “Self-Terminating Growth of Platinum Films by Electrochemical Deposition” Yihua Liu, Dincer Gokcen, Dincer Gokcen, Ugo Bertocci, Tom Moffat, Science 338(6112):1327-30 (2012); [7] "Electrodeposition of Adherent Submicron to Micron Thick Manganese Dioxide Films with Optimized Current Collector Interface for 3D Li-Ion Electrodes" Marina Timmermans, Nouha Labyedh, Felix Mattelaer, Stanislaw Zankowski, Stella Deheryan, Christophe Detavernier, and Philippe M. Vereecken, J. Electrochem. Soc. 164 , 14, D954-D963 (2017); [8] “Self-limiting electropolymerisation of ultrathin, pinhole free poly(phenylene oxide) film on Carbon Nanosheets” S. Deheryan, D. J. Cott, R. Muller, M. Heyns and P. M. Vereecken, Carbon, , 88, 42-50, (2015). Figure 1

X-ray Microspectroscopy and Ptychography on Nanoscale Structures in Rock Varnish

X-ray microspectroscopy is a powerful analytical method in geoscientific and environmental research as it provides a unique combination of nanoscale imaging with high spectroscopic sensitivity at relatively low beam-related sample damage. In this study, “classical” scanning transmission soft X-ray microscopy (STXM) with X-ray absorption spectroscopy and the recently established soft X-ray ptychography are applied to the analysis of selected rock varnish samples from urban and arid desert environments. X-ray ptychography enhances the spatial resolution relative to STXM by up to 1 order of magnitude. With its high chemical sensitivity, it can resolve nanoscale differences in valence states of the key varnish elements manganese (Mn) and iron. Our results emphasize the complex nanoarchitecture of rock varnish as well as the diverse mineralogy of the Mn oxy–hydroxide matrix and its embedded dust grains. In contrast to the fast-growing urban varnish, the slow-growing arid desert varnish revealed a remarkable nanoscale stratification of alternating Mn valence states, providing hints on the layer-wise and still enigmatic growth process.

Enhanced oxygen reduction and methanol oxidation reaction over self-assembled Pt-M (M = Co, Ni) nanoflowers

Herein, we introduce a facile approach to synthesize a unique class of Pt-M (M = Ni, Co) catalysts with a nanoflower structure for boosting both oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR). By controlling the surface-active agents, we modified the functional groups surrounding the Pt atoms, tuned the alloying of Pt and the transition metals Ni and Co, and prepared two different kinds of nanodendrites. Their successful synthesis depends on the selection and amount of surfactants (hexadecyltrimethylammonium bromide (CTAB), Polyvinylpyrrolidone (PVP)). Besides, by controlling reaction time, we also explored the forming procedures for Pt-Co globularia nanodendrite (Pt-Co GND) and Pt-Ni petalody nanodendrite (Pt-Ni PND). Our investigation highlights the importance of complex nanoarchitecture, which enables surface and interface modification to achieve excellent catalytic performance in fuel cell electrocatalysis. The characterization of the as-prepared catalysts reveals a high electrochemical surface area and mass activity (2041 mAmgPt-1and 950 mAmgPt-1 for Pt-Co GND and Pt-Ni PND, respectively, for ORR). Furthermore, Pt-Co GND showed a high MOR activity, with a mass activity value recorded at 1615 mAmgPt-1 which is far superior to that for Pt/C. Moreover, both catalysts retain high activity after accelerated durability tests (ADTs). The electron transfer number was calculated by performing the rotating ring-disk electrode (RRDE) measurements. Due to abundant active sites of Pt, both Pt-Co GND and Pt-Ni PND exhibit a 4e− pathway for ORR with electron transfer number of >3.95.

Surfactant-guided spatial assembly of nano-architectures for molecular profiling of extracellular vesicles

The controlled assembly of nanomaterials into desired architectures presents many opportunities; however, current preparations lack spatial precision and versatility in developing complex nano-architectures. Inspired by the amphiphilic nature of surfactants, we develop a facile approach to guide nanomaterial integration – spatial organization and distribution – in metal-organic frameworks (MOFs). Named surfactant tunable spatial architecture (STAR), the technology leverages the varied interactions of surfactants with nanoparticles and MOF constituents, respectively, to direct nanoparticle arrangement while molding the growing framework. By surfactant matching, the approach achieves not only tunable and precise integration of diverse nanomaterials in different MOF structures, but also fast and aqueous synthesis, in solution and on solid substrates. Employing the approach, we develop a dual-probe STAR that comprises peripheral working probes and central reference probes to achieve differential responsiveness to biomarkers. When applied for the direct profiling of clinical ascites, STAR reveals glycosylation signatures of extracellular vesicles and differentiates cancer patient prognosis.

A luminescent view of the clickable assembly of LnF3 nanoclusters

Nanoclusters (NCs) bridge the gap between atoms and nanomaterials in not only dimension but also physicochemical properties. Precise chemical and structural control, as well as clear understanding of formation mechanisms, have been important to fabricate NCs with high performance in optoelectronics, catalysis, nanoalloys, and energy conversion and harvesting. Herein, taking advantage of the close chemical properties of Ln3+ (Ln = Eu, Nd, Sm, Gd, etc.) and Gd3+–Eu3+ energy transfer ion-pair, we report a clickable LnF3 nanoparticle assembly strategy allowing reliable fabrication of diversely structured NCs, including single-component, dimeric, core-shelled/core-shell-shelled, and reversely core-shelled/core-shell-shelled, particularly with synergized optical functionalities. Moreover, the purposely-embedded dual luminescent probes offer great superiority for in situ and precise tracking of tiny structural variations and energy transfer pathways within complex nanoarchitectures.

Intensified Energy Storage in High-Voltage Nanohybrid Supercapacitors via the Efficient Coupling between TiNb2O7/Holey-rGO Nanoarchitectures and Ionic Liquid-Based Electrolytes.

Obtaining a comprehensive understanding of the energy storage mechanisms, interface compatibility, electrode-electrolyte coupling, and synergistic effects in carefully programmed nanoarchitectural electrodes and complicated electrolyte systems will provide a shortcut for designing better supercapacitors. Here, we report the intrinsic relationships between the electrochemical performances and microstructures or composition of complex nanoarchitectures and formulated electrolytes. We observed that isolated TiNb2O7 nanoparticles provided both a Faradaic intercalation contribution and a surface pseudocapacitance. The holey graphenes partitioned by nanoparticles not only fostered the fast transport of both electrons and ions but also provided additional electrical double-layer capacitance. The charge contributions from the diffusion-controlled intercalation process and capacitive behaviors, double-layer charging, and pseudocapacitance, were quantitatively distinguished in different electrolytes including a formulated ionic-liquid mixture, various nanocomposite ionogel electrolytes, and an organic LiPF6 electrolyte. A steered molecular dynamics simulation method was used to unveil the underlying principles governing the high-rate capability of holey nanoarchitectures. High energy density and high rate capability in solid-state supercapacitors were achieved using the Faradaic contributions from the lithium-ion insertion process and its surface charge-transfer process in combination with the non-Faradaic contribution from the double-layer effects. The work suggests that practical high-voltage supercapacitors with programmed performances and high safety can be realized via the efficient coupling between emerging nanoarchitectural electrodes and formulated high-voltage electrolytes.