Review
Engineering, Chemical
Iftikhar Hussain, Muhammad Shahid, Faisal Ali, Ahmad Irfan, Zahoor H. Farooqi, Robina Begum
Summary: This article critically reviewed the synthesis, properties, and uses of methacrylic acid based microgels and their hybrids. These microgels exhibit fast and reversible swelling/deswelling behavior in response to small changes in external stimuli such as pH and ionic strength, making them widely applicable in nanotechnology, drug delivery, sensing, and catalysis. The article also provides a critical review of current research development in this field along with proposed future studies for further growth.
REVIEWS IN CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Physical
Iftikhar Hussain, Zahoor H. Farooqi, Faisal Ali, Robina Begum, Ahmad Irfan, Weitai Wu, Xiaofei Wang, Muhammad Shahid, Jan Nisar
Summary: In this study, colloidal particles of Poly(styrene-N-isopropylmethacrylamide-methacrylic acid) [P(SNM)CS] and Ag-P(SNM)CS hybrid particles were synthesized via two-step precipitation polymerization, characterized using various techniques, and their catalytic activity in the reduction of 4-nitrophenol was examined. The results show that Ag-P(SNM)CS hybrid particles exhibit excellent stability and catalytic properties, making them a promising candidate for various applications.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Pharmacology & Pharmacy
Ekaterina Naumenko, Farida Akhatova, Elvira Rozhina, Rawil Fakhrullin
Summary: This study assessed the cytotoxicity of various water-soluble, positively charged synthetic polyelectrolytes on cell cultures. Addition of polyelectrolytes disrupted 3D cellular cluster formation in a dose-dependent manner, and atomic force microscopy was used to visualize the structures of the polyelectrolyte-DNA complexes. The results revealed a relationship between the structure of the polyelectrolytes and their toxicity, which is important for optimizing drug and gene delivery systems.
Article
Construction & Building Technology
Gengtong Zhang, Huiyun Xia, Wenshuo Zhang, Yanhui Niu, Lifang Song, Huaxin Chen, Dongwei Cao
Summary: Three kinds of P(AM-co-MAA) microgels with different anion contents were synthesized and their swelling behavior in aqueous solutions was studied. The addition of multivalent cations weakened the absorption capacity of microgels in cement filtrate. The modified mortar with spherical microgels showed improved compressive strength and reduced drying shrinkage compared to cement mortar without microgels.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Dong Yang, Heli Eronen, Heikki Tenhu, Sami Hietala
Summary: Poly(N-acryloyl glycinamide-co-methacrylic acid) copolymer microgels with UCST behavior were synthesized and loaded with silver nanoparticles. The catalytic activity of the AgNP-loaded microgels in 4-nitrophenol reduction was investigated, showing the potential application of these materials in catalysis.
Article
Polymer Science
Min-Kyung Chae, Nam-Kyung Lee, Youngkyun Jung, Albert Johner
Summary: Charged polymers with random charge sequences form pearl-necklace structures, with dynamics of pearls controlled by nucleation/dissolution processes. Most sequences have a stable number of large pearls, while a few exhibit fast-switching behavior. Similar shape fluctuations are observed in intrinsically disordered protein (IDP) sequences.
Article
Chemistry, Organic
Sviatoslav Batsyts, Alexander Tombrink, Felix Lederle, Eike G. Huebner, Jan C. Namyslo, Martin Nieger, Andreas Schmidt
Summary: This paper presents dicationic bis-quinolinium salts with different types of conjugation, which can control the charge distribution and spectroscopic properties. The combination of cross-conjugated and conjugated structure elements via triple bonds results in significant shifts in UV-Vis absorption peaks.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Analytical
F. Gambino, P. Cicatiello, M. Giaquinto, A. M. Cusano, A. Aliberti, A. Micco, A. Iele, E. Iaccarino, M. Ruvo, A. Ricciardi, A. Cusano
Summary: The development of photonic-based point of care devices requires the use of compact integrated biosensing platforms enabling reliable detection performances in small volumes. The Labon-Fiber technology aims to develop miniaturized, lightweight, and light-coupled optrodes with unprecedented detection performances associated with portable, plug-and-play, and user-friendly features. It represents a step forward in establishing LOF optrodes as sensing units for optical POC, further enlarging their applicability for the detection of a broad range of relevant biomarkers.
SENSORS AND ACTUATORS B-CHEMICAL
(2022)
Article
Biochemistry & Molecular Biology
Sarah K. Wypysek, Silvia P. Centeno, Till Gronemann, Dominik Woell, Walter Richtering
Summary: Microgels with specific architectural and chemical design can selectively absorb and release small molecules, or protect their cargo from the environment. This study focuses on the synthesis and analysis of hollow anionic p(N-isopropylacrylamide-co-itaconic acid) microgels, as well as investigating their interactions with cytochrome c protein at different pH values. The results reveal that cytochrome c is mainly trapped within the microgel, with pH controlling its localization.
MACROMOLECULAR BIOSCIENCE
(2023)
Article
Biochemistry & Molecular Biology
Tatiana O. Salamatova, Mikhail Y. Laktionov, Ekaterina B. Zhulina, Oleg V. Borisov
Summary: The study uses the self-consistent field Poisson-Boltzmann framework to analyze the equilibrium partitioning of ampholytic nanoparticles between a buffer solution and a polyelectrolyte polyanionic brush. It is found that depending on the pH and salt concentration, the interaction between ionizable groups on the nanoparticle surface and the electrostatic field created by the polyelectrolyte brush can either lead to spontaneous uptake or create an electrostatic potential barrier. The absorption or repulsion of nanoparticles by the polyelectrolyte brush is determined by the insertion free energy as a function of nanoparticle distance from the grafting surface.
Article
Polymer Science
Simona Sennato, Edouard Chauveau, Stefano Casciardi, Federico Bordi, Domenico Truzzolillo
Summary: The study reveals that PNIPAm microgels synthesized in water exhibit different charge characteristics at different temperatures. When collapsed, the charged microgels undergo significant charge reversal and reentrant condensation when co-suspended with oppositely charged polyelectrolytes or nanoparticles, while their stability remains unaffected in their swollen state.
Article
Polymer Science
Mo Yang, Swapnil L. Sonawane, Zachary A. Digby, Jin G. Park, Joseph B. Schlenoff
Summary: Various types of specific interactions, including hydrophobicity, supplement the major entropic driving forces responsible for liquid-liquid phase separations in mixtures of oppositely charged polyelectrolytes. This study focused on the effects of hydrophobicity on the stability, salt concentration, and properties of polyelectrolyte complexes (PECs). It was found that the length of alkane chains in the PECs influenced their stability, salt concentration, and properties, with longer chains leading to easier doping and lower critical salt concentration for dissolution.
Article
Chemistry, Physical
Andrey A. Rudov, Ivan V. Portnov, Alisa R. Bogdanova, Igor I. Potemkin
Summary: Recently, the ability to synthesize hollow polyelectrolyte nano- and microgels has opened up new possibilities for controlled release of guest molecules. However, the molecular understanding of the role of network topology, cross-link distribution, and electrostatic interactions in the response of hollow microgels to stimuli is still limited. To address this, molecular dynamics simulations were used to study the structural properties of hollow microgels under different conditions.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Review
Polymer Science
Vladimir Muronetz, Denis Pozdyshev, Pavel Semenyuk
Summary: This review discusses the application of polyelectrolytes, particularly synthetic polyanions and polycations, for immobilizing enzymes and regulating their properties. It focuses on the use of polyelectrolytes to create complex systems such as self-regulated enzyme-polyelectrolyte complexes, artificial chaperones, polyelectrolyte brushes, layer-by-layer immobilization, and others. The review also includes a section on molecular modeling of protein-polyelectrolyte interactions.
Article
Engineering, Chemical
D. J. Bell, S. Ludwanowski, A. Luken, B. Sarikaya, A. Walther, M. Wessling
Summary: This study utilizes temperature responsive microgels to form an adaptive separation layer, with control over thickness and density through crosslinking, achieving controllable retention and compression performance.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Anne C. Nickel, Timon Kratzenberg, Steffen Bochenek, Maximilian M. Schmidt, Andrey A. Rudov, Andreas Falkenstein, Igor I. Potemkin, Jerome J. Crassous, Walter Richtering
Summary: This study investigates the two-dimensional ordering of different core-shell microgels with varying softness and size at oil-water interfaces, revealing that softness affects the alignment of tip-to-tip or side-to-side ordering, i.e., the alignment mode, along with hardness and size. Thin and harder microgel shells lead to side-to-side ordering, while large, soft microgel shells result in tip-to-tip alignment.
Article
Chemistry, Multidisciplinary
Anne C. Nickel, Andrey A. Rudov, Igor I. Potemkin, Jerome J. Crassous, Walter Richtering
Summary: This study compares the interfacial deformation and assembly of anisotropic core-shell and hollow microgels and highlights the importance of microgel shape and stiffness on their behavior at the interface.
Editorial Material
Chemistry, Multidisciplinary
Atsushi Takahara, Walter Richtering, Gilbert C. Walker
Article
Chemistry, Multidisciplinary
Larisa Sigolaeva, Dmitry Pergushov, Snezhana Yu Gladyr, Ilya N. Kurochkin, Walter Richtering
Summary: This research highlights the benefits of microgel's stimuli-responsiveness for surface modification and the construction of microgel-enzyme biosensor constructs. The adsorption behavior of poly(N-isopropylacrylamide-co-N-(3-dimethylaminopropyl)methacrylamide) microgel is examined using atomic force microscopy (AFM) and quartz-crystal microbalance with dissipation monitoring (QCM-D). The study shows that the microgel exhibits enhanced adsorption onto hydrophobic surfaces at elevated pH and temperature, leading to a high surface coverage and a large adsorbed mass. The electrostatic loading of enzymes onto the surface-bound microgel is also demonstrated, showing a highly-capacious integration of biomolecules into the microgel films. The biosensor responses of the microgel-enzyme films fabricated onto screen-printed graphite electrodes are assessed, exemplifying a biorelated application. This research provides a comprehensive understanding of the relationship between the stimuli-responsive properties of microgel, its deposition onto surfaces, and the integration of enzymes, offering insights for easy engineering of biosensor systems.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Engineering, Environmental
Jiajia Xu, Huawei Qiao, Kai Yu, Mingfeng Chen, Canpei Liu, Walter Richtering, Huagui Zhang
Summary: In this study, smart foams stabilized by Cu2+ responsive microgels were presented as a proof-of-concept and demonstrated their potential for selective recovery of Cu2+ from competitive ions. The research laid foundations for the development of microgel-based flotation as a smart and green technology for Cu2+ recovery.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Max Hohenschutz, Pierre Bauduin, Carlos G. Lopez, Beate Foerster, Walter Richtering
Summary: Nanometer-sized anions (nano-ions) exhibit superchaotropic behavior, which enhances the viscosity and induces gelation of aqueous solutions of non-ionic cellulose ethers (CEs). This is due to the interplay of attractive and repulsive forces between CE-chains upon nano-ion binding. Superchaotropic nano-ion binding is a novel and general physical crosslinking motif for CE-solutions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Biochemistry & Molecular Biology
Sarah K. Wypysek, Silvia P. Centeno, Till Gronemann, Dominik Woell, Walter Richtering
Summary: Microgels with specific architectural and chemical design can selectively absorb and release small molecules, or protect their cargo from the environment. This study focuses on the synthesis and analysis of hollow anionic p(N-isopropylacrylamide-co-itaconic acid) microgels, as well as investigating their interactions with cytochrome c protein at different pH values. The results reveal that cytochrome c is mainly trapped within the microgel, with pH controlling its localization.
MACROMOLECULAR BIOSCIENCE
(2023)
Article
Chemistry, Physical
Alexander Petrunin, Steffen Bochenek, Walter Richtering, Andrea Scotti
Summary: Ultra-low crosslinked (ULC) nanogels can efficiently stabilize emulsions, showing resistance to droplet flocculation, stability against coalescence, and responsiveness to temperature changes. The polymer-particle duality of ULC nanogels can be utilized to enhance emulsion properties for various applications.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Polymer Science
Thomas Nevolianis, Andrea Scotti, Alexander V. Petrunin, Walter Richtering, Kai Leonhard
Summary: Obtaining deuterated micro- and nanogels is crucial for studying their architecture and response to crowding. Experimental studies have shown that deuterated microgels have a higher volume phase transition temperature (VPTT) than hydrogenated microgels. However, the impact of deuteration on microgel properties is not fully understood, raising questions about their responsiveness, structure, and compressibility.
Article
Engineering, Biomedical
Mattis Wachendoerfer, Eva Miriam Buhl, Ghazi Ben Messaoud, Walter Richtering, Horst Fischer
Summary: This study investigates the cross-linking mechanisms of fibrin-collagen blends and suggests that chemical cross-linkers have a minor role. It is found that pH and thrombin concentration play a crucial role in the synthesis of blends with high stiffness and hydrolytic stability. The study reveals that the blends mainly cross-link through physical interactions, leading to a highly interpenetrating fibrous network with interconnected open-porous microstructures.
ADVANCED HEALTHCARE MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Fabian Hagemans, Fabrizio Camerin, Nabanita Hazra, Janik Lammertz, Frederic Dux, Giovanni Del Monte, Olli-Ville Laukkanen, Jerome J. Crassous, Emanuela Zaccarelli, Walter Richtering
Summary: Hollow microgels are interesting model systems that can deform, interpenetrate, and shrink under certain conditions. In this study, microgels with a micrometer-sized cavity were characterized using fluorescence microscopy techniques. It was found that these microgels reversibly buckle above a critical osmotic pressure, unlike smaller hollow microgels which deswell at high volume fractions. Simulations confirmed the buckling transition and suggested that a thin shell model theory can describe the behavior of these microgels. The microgels, referred to as microgel capsules, can be used to probe interfacial properties and mimic anisotropic responsive biological systems.
Article
Chemistry, Multidisciplinary
Siyang He, Simon Schog, Ying Chen, Yuxin Ji, Sinan Panitz, Walter Richtering, Robert Goestl
Summary: The serial connection of multiple stimuli-responses in polymer architectures enables the gating of functional material processes on demand. In this study, a photoswitchable diarylethene is used as a crosslinker in poly(N-vinylcaprolactam) microgels to induce a shift in volume phase-transition temperature (VPTT). By switching the microgels from the swollen to the collapsed state using light, their response to mechanical force can be controlled. This photoinduced mechanical cloaking system operates on a polymer topology level and is universally applicable.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Ghazi Ben Messaoud, Sanja Aveic, Mattis Wachendoerfer, Horst Fischer, Walter Richtering
Summary: Porous hydrogels derived from aqueous two-phase systems (ATPS) are an interesting alternative to overcome the restricted porosity of most hydrogels in vitro. By tuning the phase behavior and concentration, ATPS hydrogels with three distinct microstructures, including bicontinuous hydrogels with interconnected pores, can be formed. These ATPS hydrogels show cytocompatibility and can sustain their unique porous structure when processed by inkjet and microextrusion techniques.
Review
Chemistry, Multidisciplinary
M. Friederike Schulte, Emilia Izak-Nau, Susanne Braun, Andrij Pich, Walter Richtering, Robert Goestl
Summary: In this tutorial review, we discuss the mechanical properties of microgels and their measurement methods using atomic force microscopy. We also provide the synthetic background to understand how specific architectures and chemical functionalities enable these mechanical properties. Furthermore, we elucidate how the interaction of force with microgels can activate latent functionality. This review aims to enhance the understanding of this emerging field by introducing and connecting different research areas.
CHEMICAL SOCIETY REVIEWS
(2022)
Review
Chemistry, Physical
Swaminath Bharadwaj, Bart-Jan Niebuur, Katja Nothdurft, Walter Richtering, Nico F. A. van der Vegt, Christine M. Papadakis
Summary: Cononsolvency is an intriguing phenomenon where a polymer collapses in a mixture of good solvents. It has been widely observed in different systems and has applications in various fields. In the past decade, there has been a renewed interest in understanding the molecular mechanisms driving cononsolvency.
