Article
Multidisciplinary Sciences
L. Alvarez, M. A. Fernandez-Rodriguez, A. Alegria, S. Arrese-Igor, K. Zhao, M. Kroeger, Lucio Isa
Summary: Researchers have created responsive microswimmers that can adapt their motility via internal reconfiguration, presenting exciting opportunities for the development of tactic active materials. Alvarez et al. have implemented an independent reconfiguration scheme, bringing small active particles one step closer to adaptive, autonomous behaviour.
NATURE COMMUNICATIONS
(2021)
Article
Polymer Science
Migle Babelyte, Laura Peciulyte, Vesta Navikaite-Snipaitiene, Joana Bendoraitiene, Volodymyr Samaryk, Ramune Rutkaite
Summary: Thermoresponsive chitosan-graft-poly(N-isopropylacrylamide) copolymers with different compositions were synthesized. The chemical structure of the copolymers was confirmed and their lower critical solution temperature (LCST) behavior was assessed. Copolymers with a certain content of poly(N-isopropylacrylamide) side chains demonstrated LCST behavior and could potentially be used in drug delivery systems or tissue engineering.
Review
Materials Science, Multidisciplinary
Lin Tang, Ling Wang, Xiao Yang, Yiyu Fen, Yu Li, Wei Feng
Summary: PNIPAM-based smart hydrogels are important smart materials with unique thermo-responsive properties and promising applications. This review summarizes the development, fundamental design, synthetic strategies, and potential applications of these materials in various fields.
PROGRESS IN MATERIALS SCIENCE
(2021)
Article
Polymer Science
Isaac J. Gresham, Ben A. Humphreys, Joshua D. Willott, Edwin C. Johnson, Timothy J. Murdoch, Grant B. Webber, Erica J. Wanless, Andrew R. J. Nelson, Stuart W. Prescott
Summary: The structure of grafted-from poly(N-isopropylacrylamide) brushes under confinement shows a uniform internal structure and specific volume fraction distribution, eliminating the critical transition point in their thermal response. Different experimental methods find qualitative agreement, but variations exist due to path-dependent behavior.
Article
Polymer Science
Chia-Hsin Ko, Cristiane Henschel, Geethu P. Meledam, Martin A. Schroer, Peter Mueller-Buschbaum, Andre Laschewsky, Christine M. Papadakis
Summary: The temperature-dependent phase behavior and self-assembly behavior of a thermoresponsive amphiphilic diblock copolymer in aqueous solution were studied, revealing a lower critical solution temperature (LCST) behavior at 31.1 degrees Celsius and the formation of different structures of micelles.
Article
Polymer Science
Chia-Hsin Ko, Cristiane Henschel, Geethu P. Meledam, Martin A. Schroer, Renjun Guo, Luka Gaetani, Peter Mueller-Buschbaum, Andre Laschewsky, Christine M. Papadakis
Summary: The self-assembly of the thermoresponsive amphiphilic diblock copolymer PMMA(21)-b-PNIPAM(283) in various water/methanol mixtures was studied. It was found that the solvent composition significantly affected the internal morphology of micelles and the conformation of dissolved chains.
Article
Polymer Science
Fang Yin, Pascale Laborie, Barbara Lonetti, Yannick Coppel, Nancy Lauth-de Viguerie, Jean-Daniel Marty, Stephane Gineste
Summary: Doubly thermo-and pH-responsive PNIPAM-b-PDEAEAM polymers were synthesized by RAFT polymerization. The properties of these polymers and corresponding homopolymers in solution depend on pH and the protonation degree of the diethylamino moiety. The behavior of the polymers is also influenced by the nature of the polymer chain ends. At pH 10, both PNIPAM and PDEAEAM blocks contribute to phase transition and form stable spherical nanoobjects. At pH 4, PNIPAM-b-PDEAEAM with longer PDEAEAM length exhibits a two-step thermoresponsive behavior and forms large aggregates with a positively charged shell.
Article
Environmental Sciences
Ye -Lim Han, Hye-Ran Kim, Hyun-Kyung Kim, Jae -Woo Park
Summary: A series of thermosensitive and magneto-responsive dendrimers were synthesized and their properties at different temperatures were studied. The results showed that PNIPAM-g-MCD could encapsulate and fix benzene molecules below the critical solution temperature, while it could disrupt oil-water emulsions above the critical solution temperature.
Article
Chemistry, Analytical
Jung Gi Choi, Hocheol Gwac, Yongwoo Jang, Christopher Richards, Holly Warren, Geoffrey Spinks, Seon Jeong Kim
Summary: The diving and surfacing device fabricated from thermo-sensitive poly(N-isopropylacrylamide) or a poly(N-isopropylacrylamide)-containing hydrogel can exhibit fast and reversible diving/surfacing cycles in response to changing temperature. Modulation of the interaction between poly(N-isopropylacrylamide) chains and water molecules at different temperatures allows for control of gel density through swelling and de-swelling, enabling the gel to surface in water when heated and sink when cooled. Reversible diving/surfacing cycles of the device can also be achieved when exposed to electrical and ultrasonic stimuli.
Article
Pharmacology & Pharmacy
Ana Dinic, Vesna Nikolic, Ljubisa Nikolic, Snezana Ilic-Stojanovic, Stevo Najman, Maja Urosevic, Ivana Gajic
Summary: The aim of this study was to investigate p(NIPAM) hydrogels cross-linked with ethylene glycol dimethacrylate as carriers for sulfanilamide. The structural characterization before and after sulfanilamide incorporation was done using FTIR, XRD and SEM. The swelling behavior of p(NIPAM) hydrogels of various cross-linking degrees was monitored with respect to temperature and pH, and the release of sulfanilamide was examined. The results showed that p(NIPAM) hydrogels are promising carriers for sulfanilamide due to their thermosensitivity, volume phase transition temperature close to physiological temperature, and satisfactory results for sulfanilamide incorporation and release.
Article
Polymer Science
Parvaneh Gheysoori, Azin Paydayesh, Maryam Jafari, Hamed Peidayesh
Summary: This study focuses on the development of thermoresponsive nanocomposite hydrogels for minimally invasive drug delivery. Gelatin-based hydrogels with poly (N-isopropylacrylamide) (PNIPAM) were prepared using response surface methodology. The PNIPAM nanoparticles showed successful polymerization and a reversible sol-gel transition close to body temperature. These nanocomposite hydrogels demonstrated antibacterial activity and good potential for targeted drug delivery.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Mitsuhiro Matsumoto, Taka-Aki Asoh, Tatsuya Shoji, Yasuyuki Tsuboi
Summary: This study demonstrates liquid-liquid phase separation of a thermoresponsive polymer through near-infrared laser-induced coacervation and coil-to-globule phase transition. By focusing a laser beam, single polymer microdroplets can be formed and trapped at the focal point, allowing for selective analysis. The results indicate that PDEA undergoes dehydration and coacervation in addition to a coil-to-globule phase transition.
Article
Biophysics
Alberto Guerron, Huu Trong Phan, Carolina Penaloza-Arias, Davide Brambilla, Valerie Gaelle Roullin, Suzanne Giasson
Summary: The attachment/detachment of cells on responsive polymer-coated surfaces is influenced by various factors including electrostatic interactions, wettability and swelling of the polymer coating. In this study, dual thermo- and pH-responsive cationic poly(N-isopropylacrylamide) microgels, surface-functionalized with PEG or PDMAEMA, were used as substrates to investigate their impact on cell behavior. The results showed that microgels with PEG chains had comparable cell adhesion and proliferation rates to controls, while exhibiting the best thermo-triggered cell detachment performance, especially for MCF7 and U138 cells. The hydrophilic nature of the microgel surface remained unchanged regardless of temperature and pH, contributing to this behavior. Swelling behavior influenced by pH resulted in significant cell detachment only for U138 cells. However, detachment of bEnd.3 cells could not be triggered by either temperature or pH, regardless of the microgel surface coating.
COLLOIDS AND SURFACES B-BIOINTERFACES
(2022)
Article
Polymer Science
Shafia Lateef, Nadeem Bashir Ganaie, Ghulam Mustafa Peerzada
Summary: This study investigated the ferroin-catalyzed Belousov-Zhabotinsky oscillatory chemical reaction with catechol as the organic substrate in aqueous acid media. The system exhibited oscillations within a narrow range of initial reagent concentrations and showed a long induction time and numerous oscillations at 30±0.1 degrees C. The thermosensitive polymer PNIPAA influenced the induction time and number of oscillations in the system.
Article
Polymer Science
Shin-nosuke Nishimura, Kei Nishida, Tomoya Ueda, Shohei Shiomoto, Masaru Tanaka
Summary: Poly(N-isopropylacrylamide) (PNIPAM) is a commonly used thermoresponsive polymer that has been widely applied in biological applications. However, due to the presence of a hydrogen-bond donor, PNIPAM often induces blood clot formation, making alternatives to PNIPAM with aprotic polar functional groups necessary. In this study, acrylate polymers containing the aprotic polar functional group pyrrolidone ring were synthesized, and their lower critical solution temperatures (LCSTs) could be precisely controlled. These polymers demonstrated good blood compatibility and cell affinity, and interestingly, could activate macrophages without cytotoxicity when their hydrophobic/hydrophilic balance was altered.
Article
Physics, Applied
Filippos Harlaftis, Dean Kos, Qianqi Lin, Kevin T. P. Lim, Calvin Dumesnil, Jeremy J. J. Baumberg
Summary: Dielectrophoresis is found to drive the motion of nanoparticles through the interaction of their induced dipoles with a non-uniform electric field. The reversible aggregation of 100 nm diameter gold nanoparticles in electrode gaps is experimentally observed under MHz frequencies. A frequency resonance is observed, resulting in a significant increase in the density of gold nanoparticle clouds. A simple model is proposed to explain this reversibility, suggesting the possibility of substantial control over nanoparticle separation.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Demelza Wright, Sara Sangtarash, Niclas S. Mueller, Qianqi Lin, Hatef Sadeghi, Jeremy J. Baumberg
Summary: This study demonstrates that molecules containing vibrational Stark shift reporters can be used to measure DC electric fields in situ. However, it is found that the uniform field DFT calculations cannot accurately model the behavior of the three strongest vibrational modes in molecules forming a monolayer on an electrode. It is shown that the measured Stark shifts are explained by partial electrical double-layer penetration into the molecular layer, which is sensitive to the local environment.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Santiago Rodriguez-Jimenez, Hongwei Song, Erwin Lam, Demelza Wright, Andrea Pannwitz, Shannon A. Bonke, Jeremy J. Baumberg, Sylvestre Bonnet, Leif Hammarstrom, Erwin Reisner
Summary: This study demonstrates the use of self-assembled amphiphilic photosensitizers and catalysts in lipid membranes for photocatalytic CO2 reduction. Membrane-anchored alkylated cobalt porphyrin shows higher catalytic activity and selectivity compared to its water-soluble counterpart. Self-assembly increases the charge separation state lifetime and enhances the electron transfer to the catalyst.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Ermanno Miele, Wesley M. Dose, Ilya Manyakin, Michael H. Frosz, Zachary Ruff, Michael F. L. De Volder, Clare P. Grey, Jeremy J. Baumberg, Tijmen G. Euser
Summary: New analytical tools are urgently needed to identify chemical degradation and failure mechanisms in Li-ion batteries. In this study, an operando Raman spectroscopy method based on hollow-core optical fibres was developed to monitor the chemistry of liquid electrolytes during battery cycling. Analysis of spectroscopy measurements revealed changes in electrolyte additives and solvents ratio with respect to cell voltage, indicating the potential to track lithium-ion solvation dynamics.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Javier Redolat, Maria Camarena-Perez, Amadeu Griol, Miroslavna Kovylina, Angelos Xomalis, Jeremy J. Baumberg, Alejandro Martinez, Elena Pinilla-Cienfuegos
Summary: Controlled integration of metallic nanoparticles onto photonic nanostructures enables the realization of complex devices for extreme light confinement and enhanced light-matter interaction. A methodology for precise transfer and positioning of individual nanoparticles onto different photonic nanostructures is presented, using soft lithography printing. Raman spectroscopy confirms enhanced light-matter interactions in the resulting nanophotonic devices.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Rohit Chikkaraddy, Junyang Huang, Dean Kos, Eoin Elliott, Marlous Kamp, Chenyang Guo, Jeremy J. Baumberg, Bart de Nijs
Summary: Plasmonic nanoantennas can focus light at nanometer length scales, resulting in intense field enhancements. The tightest optical confinements achieved in plasmonic gaps depend on the gap spacing, refractive index, and facet width, making antenna shape tuning challenging. However, by controlling the surrounding refractive index, efficient frequency tuning and enhanced in-/output coupling can be achieved through retardation matching, enabling dark modes to become optically active and improving various functionalities.
Article
Chemistry, Multidisciplinary
Raphael P. B. Jacquat, Georg Krainer, Quentin A. E. Peter, Ali Nawaz Babar, Oliver Vanderpoorten, Catherine K. Xu, Timothy J. Welsh, Clemens F. Kaminski, Ulrich F. Keyser, Jeremy J. Baumberg, Tuomas P. J. Knowles
Summary: This paper presents an approach called nanocavity diffusional sizing (NDS) that relies on nanocavity confinement to measure the size of nanoscale particles and single biomolecules in solution. It uses particle residence times within nanofluidic cavities to determine their hydrodynamic radii. Experimental results show that the residence times scale linearly with the sizes of nanoscale colloids, protein aggregates, and single DNA oligonucleotides. NDS offers a new optofluidic approach for rapid and quantitative sizing of nanoscale particles with potential applications in nanobiotechnology, biophysics, and clinical diagnostics.
Article
Chemistry, Physical
Alex Poppe, Jack Griffiths, Shu Hu, Jeremy J. Baumberg, Margarita Osadchy, Stuart Gibson, Bart de Nijs
Summary: Atomic-scale features play crucial roles in metal-molecule interactions and have significant implications in various applications. However, studying these interactions is challenging due to the small size and transient nature of atomic-scale structures. In this study, we combine single-molecule surface-enhanced Raman spectroscopy with machine learning to extract spectra of perturbed molecules and investigate the formation dynamics of adatoms on metal surfaces. This approach provides unique insights into atomic-scale processes and helps us understand how metallic protrusions form and interact with nearby molecules. Our technique opens new possibilities for controlling metal-molecule interactions at an atomic level and contributes to rational heterogeneous catalyst design.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Sara Rocchetti, Alexander Ohmann, Rohit Chikkaraddy, Gyeongwon Kang, Ulrich F. Keyser, Jeremy J. Baumberg
Summary: Developing highly enhanced plasmonic nanocavities allows direct observation of light-matter interactions at the nanoscale. With DNA origami, precise nanopositioning of single-quantum emitters in ultranarrow plasmonic gaps enables detailed study of their modified light emission. By developing nanoparticle-on-mirror constructs with DNA nanostructures as reliable and customizable spacers for nanoparticle binding, it is revealed that the traditional understanding of Purcell-enhanced molecular dye emission is misleading, and the enhanced dipolar dye polarizability greatly amplifies optical forces acting on the facet Au atoms, causing their rapid destabilization. Different dyes exhibit emission spectra dominated by inelastic (Raman) scattering rather than fluorescence, challenging the conventional theories in the field of quantum optics using plasmonics.
Article
Optics
Rohit Chikkaraddy, Rakesh Arul, Lukas A. Jakob, Jeremy J. Baumberg
Summary: This study proposes a method for detecting molecular vibrations in the mid-infrared range at room temperature. By assembling molecules into a plasmonic nanocavity resonant at both mid-infrared and visible wavelengths, and optically pumping them below the electronic absorption band, successful conversion of mid-infrared light and observation of enhanced visible luminescence were achieved.
Article
Chemistry, Multidisciplinary
Aoife Gregg, Michael De Volder, Jeremy J. Baumberg
Summary: Light-responsive microactuators composed of carbon nanotube and hydrogel composites exhibit efficient radiative heating capture and fast response time. The kinetics of these microactuators are limited by polymer diffusion. Additionally, these actuators have potential applications as microswimmers.
Article
Chemistry, Multidisciplinary
Marika Niihori, Tamas Foeldes, Charlie A. Readman, Rakesh Arul, David-Benjamin Grys, Bart de Nijs, Edina Rosta, Jeremy J. Baumberg
Summary: This study demonstrates the sensing of neurotransmitters at nm concentrations using self-assembled monolayers of plasmonic Au nanoparticles. By integrating Fe(III) sensitizers into nanogaps, enhanced surface-enhanced Raman spectroscopy is achieved for dopamine sensing. The transparent glass substrates allow for repeated sensing in different analytes.
Article
Chemistry, Multidisciplinary
David-Benjamin Grys, Marika Niihori, Rakesh Arul, Sarah May Sibug-Torres, Elle W. Wyatt, Bart de Nijs, Jeremy J. Baumberg
Summary: We demonstrate reliable creation of multiple layers of Au nanoparticles in random close-packed arrays with sub-nm gaps as a sensitive surface-enhanced Raman scattering substrate. The nanogaps can be precisely controlled below 1 nm by removing and replacing the original molecules with scaffolding ligands using oxygen plasma etching. The resulting high-performance fluidic sensing cells allow cyclic cleaning and reusing of the films for various analytes.
Article
Optics
Angelos Xomalis, Jeremy J. Baumberg
Summary: In this article, a multichannel lock-in vibrational spectroscopy method is reported, which utilizes acousto-optic modulators to convert nanosecond periodic temporal perturbations into spatially distinct spectra. By projecting the perturbed and reference spectra onto different locations of the spectrometer image, they can be simultaneously resolved. This multichannel time-resolved technique is applied to detect molecular frequency upconversion in plasmonic nanocavities through perturbed Raman scattering at different wavelengths. The phase-sensitive detection scheme can be applied to any spectroscopy within the visible and near-infrared wavelength ranges.
Article
Nanoscience & Nanotechnology
Wei-Hsin Chen, Wenting Wang, Qianqi Lin, David-Benjamin Grys, Marika Niihori, Junyang Huang, Shu Hu, Bart de Nijs, Oren A. Scherman, Jeremy J. Baumberg
Summary: A liquid-based surface-enhanced Raman spectroscopy assay, called PSALM, has been developed for the selective detection of neurotransmitters (NTs) in urine with a detection limit below the physiological range. This assay involves quick and simple mix-and-measure protocols with nanoparticles (NPs), where Fe-III bridges NTs and gold NPs in sensing hotspots. The optimized PSALM allows long-term monitoring of NT variation in urine, enabling the development of NTs as predictive or correlative biomarkers for clinical diagnosis.
ACS NANOSCIENCE AU
(2023)
