Journal: Advanced Science

Abbreviation

Adv. Sci.

Publisher

Wiley

Journal Volumes

ISSN

2198-3844

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2017 - 201982020 - 202548
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Publications1 - 10 of 56
  • Superior Acetone Selectivity in Gas Mixtures by Catalyst‐Filtered Chemoresistive Sensors
    Item type: Journal Article
    Weber, Ines; Braun, Hugo P.; Krumeich, Frank; et al. (2020)
    Advanced Science
    Acetone is a toxic air pollutant and a key breath marker for non‐invasively monitoring fat metabolism. Its routine detection in realistic gas mixtures (i.e., human breath and indoor air), however, is challenging, as low‐cost acetone sensors suffer from insufficient selectivity. Here, a compact detector for acetone sensing is introduced, having unprecedented selectivity (>250) over the most challenging interferants (e.g., alcohols, aldehydes, aromatics, isoprene, ammonia, H2, and CO). That way, acetone is quantified with fast response (<1 min) down to, at least, 50 parts per billion (ppb) in gas mixtures with such interferants having up to two orders of magnitude higher concentration than acetone at realistic relative humidities (RH = 30–90%). The detector consists of a catalytic packed bed (30 mg) of flame‐made Al2O3 nanoparticles (120 m2 g−1) decorated with Pt nanoclusters (average size 9 nm) and a highly sensitive chemo‐resistive sensor made by flame aerosol deposition and in situ annealing of nanostructured Si‐doped ε‐WO3 (Si/WO3). Most importantly, the catalytic packed bed converts interferants continuously enabling highly selective acetone sensing even in the exhaled breath of a volunteer. The detector exhibits stable performance over, at least, 145 days at 90% RH, as validated by mass spectrometry.
  • Mechanochromic Reconfigurable Metasurfaces
    Item type: Journal Article
    Karvounis, Artemios; Aspiotis, Nikolaos; Zeimpekis, Ioannis; et al. (2019)
    Advanced Science
    The change of optical properties that some usually natural compounds or polymeric materials show upon the application of external stress is named mechanochromism. Herein, an artificial nanomechanical metasurface formed by a subwavelength nanowire array made of molybdenum disulfide, molybdenum oxide, and silicon nitride changes color upon mechanical deformation. The aforementioned deformation induces reversible changes in the optical transmission (relative transmission change of 197% at 654 nm), thus demonstrating a giant mechanochromic effect. Moreover, these types of metasurfaces can exist in two nonvolatile states presenting a difference in optical transmission of 45% at 678 nm, when they are forced to bend rapidly. The wide optical tunability that photonic nanomechanical metasurfaces, such as the one presented here, possess by design, can provide a valuable platform for mechanochromic and bistable responses across the visible and near infrared regime and form a new family of smart materials with applications in reconfigurable, multifunctional photonic filters, switches, and stress sensors.
  • Simultaneous Nanothermometry and Deep‐Tissue Imaging
    Item type: Journal Article
    Gschwend, Pascal M.; Niedbalka, David; Gerken, Lukas R.H.; et al. (2020)
    Advanced Science
    Bright, stable, and biocompatible fluorescent contrast agents operating in the second biological window (1000–1350 nm) are attractive for imaging of deep‐lying structures (e.g., tumors) within tissues. Ideally, these contrast agents also provide functional insights, such as information on local temperature. Here, water‐dispersible barium phosphate nanoparticles doped with Mn5+ are made by scalable, continuous, and sterile flame aerosol technology and explored as fluorescent contrast agents with temperature‐sensitive peak emission in the NIR‐II (1190 nm). Detailed assessment of their stability, toxicity with three representative cell lines (HeLa, THP‐1, NHDF), and deep‐tissue imaging down to about 3 cm are presented. In addition, their high quantum yield (up to 34%) combined with excellent temperature sensitivity paves the way for concurrent deep‐tissue imaging and nanothermometry, with biologically well‐tolerated nanoparticles.
  • Magnetic Resonance Imaging-Compatible Optically Powered Miniature Wireless Modular Lorentz Force Actuators
    Item type: Journal Article
    Mutlu, Senol; Yasa, Oncay; Erin, Onder; et al. (2021)
    Advanced Science
    Minimally invasive medical procedures under magnetic resonance imaging (MRI) guidance have significant clinical promise. However, this potential has not been fully realized yet due to challenges regarding MRI compatibility and miniaturization of active and precise positioning systems inside MRI scanners, i.e., restrictions on ferromagnetic materials and long conductive cables and limited space around the patient for additional instrumentation. Lorentz force-based electromagnetic actuators can overcome these challenges with the help of very high, axial, and uniform magnetic fields (3-7 Tesla) of the scanners. Here, a miniature, MRI-compatible, and optically powered wireless Lorentz force actuator module consisting of a solar cell and a coil with a small volume of 2.5 x 2.5 x 3.0 mm(3) is proposed. Many of such actuator modules can be used to create various wireless active structures for future interventional MRI applications, such as positioning needles, markers, or other medical tools on the skin of a patient. As proof-of-concept prototypes toward such applications, a single actuator module that bends a flexible beam, four modules that rotate around an axis, and six modules that roll as a sphere are demonstrated inside a 7 Tesla preclinical MRI scanner.
  • Synthetic Biology: Emerging Concepts to Design and Advance Adeno‐Associated Viral Vectors for Gene Therapy
    Item type: Review Article
    Wagner, Hanna J.; Weber, Wilfried; Fussenegger, Martin (2021)
    Advanced Science
    Three recent approvals and over 100 ongoing clinical trials make adeno‐associated virus (AAV)‐based vectors the leading gene delivery vehicles in gene therapy. Pharmaceutical companies are investing in this small and nonpathogenic gene shuttle to increase the therapeutic portfolios within the coming years. This prospect of marking a new era in gene therapy has fostered both investigations of the fundamental AAV biology as well as engineering studies to enhance delivery vehicles. Driven by the high clinical potential, a new generation of synthetic‐biologically engineered AAV vectors is on the rise. Concepts from synthetic biology enable the control and fine‐tuning of vector function at different stages of cellular transduction and gene expression. It is anticipated that the emerging field of synthetic‐biologically engineered AAV vectors can shape future gene therapeutic approaches and thus the design of tomorrow's gene delivery vectors. This review describes and discusses the recent trends in capsid and vector genome engineering, with particular emphasis on synthetic‐biological approaches.
  • A Highly Multi-Stable Meta-Structure via Anisotropy for Large and Reversible Shape Transformation
    Item type: Journal Article
    Risso, Giada; Sakovsky, Maria; Ermanni, Paolo (2022)
    Advanced Science
    Shape transformation offers the possibility of realizing devices whose 3D shape can be altered to adapt to different environments. Many applications would profit from reversible and actively controllable shape transformation together with a self-locking capability. Solutions that combine such properties are rare. Here, a novel class of meta-structures that can tackle this challenge is presented thanks to multi-stability. Results demonstrate that the multi-stability of the meta-structure is strictly tied to the use of highly anisotropic materials. The design rules that enable large-shape transformation, programmability, and self-locking are derived, and it is proven that the shapes can be actively controlled and harnessed to realize inchworm-inspired locomotion by strategically actuating the meta-structure. This study provides routes toward novel shape adaptive lightweight structures where a metamaterial-inspired assembly of anisotropic components leads to an unforeseen combination of properties, with potential applications in reconfigurable space structures, building facades, antennas, lenses, and soft robots.
  • A Submillimeter Continuous Variable Stiffness Catheter for Compliance Control
    Item type: Journal Article
    Lussi, Jonas; Mattmann, Michael; Sevim, Semih; et al. (2021)
    Advanced Science
    Minimally invasive robotic surgery often requires functional tools that can change their compliance to adapt to the environment and surgical needs. This paper proposes a submillimeter continuous variable stiffness (CVS) catheter equipped with a phasechange alloy that has a high stiffness variation in its different states, allowing for rapid compliance control. Variable stiffness is achieved through a variable phase boundary in the alloy due to a controlled radial temperature gradient. This catheter can be safely navigated in its soft state and rigidified to the required stiffness during operation to apply a desired force at the tip. The maximal contact force that the catheter applies to tissue can be continuously modified by a factor of 400 (~20 mN – 8N). The catheter is equipped with a magnet and a micro-gripper to perform a fully robotic ophthalmic minimally invasive surgery on an eye phantom by means of an electromagnetic navigation system (eMNS).
  • Digital Light 3D Printed Bioresorbable and NIR-Responsive Devices with Photothermal and Shape-Memory Functions
    Item type: Journal Article
    Paunović, Nevena; Marbach, Jessica; Bao, Yinyin; et al. (2022)
    Advanced Science
    Digital light processing (DLP) 3D printing is a promising technique for the rapid manufacturing of customized medical devices with high precision. To be successfully translated to a clinical setting, challenges in the development of suitable photopolymerizable materials have yet to be overcome. Besides biocompatibility, it is often desirable for the printed devices to be biodegradable, elastic, and with a therapeutic function. Here, a multifunctional DLP printed material system based on the composite of gold nanorods and polyester copolymer is reported. The material demonstrates robust near-infrared (NIR) responsiveness, allowing rapid and stable photothermal effect leading to the time-dependent cell death. NIR light-triggerable shape transformation is demonstrated, resulting in a facilitated insertion and expansion of DLP printed stent ex vivo. The proposed strategy opens a promising avenue for the design of multifunctional therapeutic devices based on nanoparticle-polymer composites.
  • Colloidal HgTe Quantum Dot/Graphene Phototransistor with a Spectral Sensitivity Beyond 3 µm
    Item type: Journal Article
    Grotevent, Matthias J.; Hail, Claudio U.; Yakunin, Sergii; et al. (2021)
    Advanced Science
    Infrared light detection enables diverse technologies ranging from night vision to gas analysis. Emerging technologies such as low‐cost cameras for self‐driving cars require highly sensitive, low‐cost photodetector cameras with spectral sensitivities up to wavelengths of 10 µm. For this purpose, colloidal quantum dot (QD) graphene phototransistors offer a viable alternative to traditional technologies owing to inexpensive synthesis and processing of QDs. However, the spectral range of QD/graphene phototransistors is thus far limited to 1.6 µm. Here, HgTe QD/graphene phototransistors with spectral sensitivity up to 3 µm are presented, with specific detectivities of 6 × 108 Jones at a wavelength of 2.5 µm and a temperature of 80 K. Even at kHz light modulation frequencies, specific detectivities exceed 108 Jones making them suitable for fast video imaging. The simple device architecture and QD film patterning in combination with a broad spectral sensitivity manifest an important step toward low‐cost, multi‐color infrared cameras.
  • Shedding Light on Extracellular Vesicle Biogenesis and Bioengineering
    Item type: Review Article
    Teng, Fei; Fussenegger, Martin (2021)
    Advanced Science
    Extracellular vesicles (EVs) are biocompatible, nano‐sized secreted vesicles containing many types of biomolecules, including proteins, RNAs, DNAs, lipids, and metabolites. Their low immunogenicity and ability to functionally modify recipient cells by transferring diverse bioactive constituents make them an excellent candidate for a next‐generation drug delivery system. Here, the recent advances in EV biology and emerging strategies of EV bioengineering are summarized, and the prospects for clinical translation of bioengineered EVs and the challenges to be overcome are discussed. © 2020 The Authors. Published by Wiley‐VCH GmbH.
Publications1 - 10 of 56