Other Chemistry Commons^™

Dynamic, Reconfigurable, And Hierarchical Biosynthetic Composites Via Collagen Self-Assembly Within Highly Crowded Microgel Pastes, Elif Narbay, Abbygail Caine, Sanika Pandit, Gabrielle Montgomery, Marion Harper, E. Daniel Cárdenas-Vásquez, Hatte Hamilton, Megan Hicks, Daniel Mattar, Kyle Choy, Marco Bisoffi, L. Andrew Lyon

Engineering Faculty Articles and Research

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The fabrication of a new class of biomimetic biomaterials is reported using nanostructured microgel pastes formed from “overpacked” assemblies of ultrasoft poly(N-isopropyl acrylamide-co-acrylic acid) microgels and their composites with collagen. Despite the solid-like nature of microgel pastes, collagen fibrillogenesis is robust and rapid, with a 3D collagen network forming throughout the paste volume. Structural organization within the composite is interrogated via a suite of microscopy methods, while rheological characterization provides insight into the static and dynamic mechanical properties of the materials. Long-range fibrillogenesis is enabled by local crowding, dynamics, and spatial reconfigurability of pastes at the …

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Assembly Of Non-Close-Packed Poly(N-Isopropylacrylamide) Microgels On Metal Halide Perovskite Films, Amal Alruwaili, Osama M. Alkhudhari, Ran Wang, Zhenyu Jia, Jennifer M. Saunders, Eugenio Picheo, Daniel T.W. Toolan, L. Andrew Lyon, Brian R. Saunders

Engineering Faculty Articles and Research

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Hypothesis

Poly(N-isopropylacryamide) microgels (PNIPAM MGs) are interesting model colloids with remarkable self-ordering properties. Metal halide perovskites (MHPs) are solution processable semiconductors that have attracted great interest for optoelectronics applications. Very few studies have considered complex co-crystallizing systems and their effects on structural order formation. This work examines PNIPAM MG ordering within a MHP matrix and investigates whether these pure PNIPAM MGs could form arrays on the MHP surface, passivate MHP defects and provide structurally colored films and solar cells.

Experiments

We use a mixed cation MHP (FA0.88MA0.12PbI3) (FA and MA are formamidinium and methylammonium) and investigate the effects …

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Highly Swelling Ph-Responsive Microgels For Dual Mode Near Infra-Red Fluorescence Reporting And Imaging, Mingning Zhu, Dongdong Lu, Qing Lian, Shanglin Wu, Wenkai Wang, L. Andrew Lyon, Weiguang Wan, Paulo Bártolo, Mark Dickinson, Brian R. Saunders

Engineering Faculty Articles and Research

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Near infra-red (NIR) fluorescence is a desirable property for probe particles because such deeply penetrating light enables remote reporting of the local environment in complex surroundings and imaging. Here, two NIR non-radiative energy transfer (NRET) fluorophores (Cy5 and Cy5.5) are coupled to preformed pH-responsive poly(ethylacrylate-methacrylic acid-divinylbenzene) microgel particles (PEA-MAA-5/5.5 MGs) to obtain new NIR fluorescent probes that are cytocompatible and swell strongly. NIR ratiometric photoluminescence (PL) intensity analysis enables reporting of pH-triggered PEA-MAA-5/5.5 MG particle swelling ratios over a very wide range (from 1–90). The dispersions have greatly improved colloidal stability compared to a reference temperature-responsive NIR MG based on …

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Using Green Emitting Ph-Responsive Nanogels To Report Environmental Changes Within Hydrogels: A Nanoprobe For Versatile Sensing, Mingning Zhu, Dongdong Lu, Shanglin Wu, Qing Lian, Wenkai Wang, L. Andrew Lyon, Weiguang Wang, Paulo Bártolo, Brian R. Saunders

Engineering Faculty Articles and Research

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Remotely reporting the local environment within hydrogels using inexpensive laboratory techniques has excellent potential to improve our understanding of the nanometer-scale changes that cause macroscopic swelling or deswelling. Whilst photoluminescence (PL) spectroscopy is a popular method for such studies this approach commonly requires bespoke and time-consuming synthesis to attach fluorophores which may leave toxic residues. A promising and more versatile alternative is to use a pre-formed nanogel probe that contains a donor/acceptor pair and then “dope” that into the gel during gel assembly. Here, we introduce green-emitting methacrylic acid-based nanogel probe particles and use them to report the local environment …

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Nanogels And Microgels: From Model Colloids To Applications, Recent Developments, And Future Trends, Mattias Karg, Andrij Pich, Thomas Hellweg, Todd Hoare, L. Andrew Lyon, J. J. Crassous, Daisuke Suzuki, Rustam A. Gumerov, Stefanie Schneider, Igor I. Potemkin, Walter Richtering

Engineering Faculty Articles and Research

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Nanogels and microgels are soft, deformable, and penetrable objects with an internal gel-like structure that is swollen by the dispersing solvent. Their softness and the potential to respond to external stimuli like temperature, pressure, pH, ionic strength, and different analytes make them interesting as soft model systems in fundamental research as well as for a broad range of applications, in particular in the field of biological applications. Recent tremendous developments in their synthesis open access to systems with complex architectures and compositions allowing for tailoring microgels with specific properties. At the same time state-of-the-art theoretical and simulation approaches offer deeper …

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Deswelling Induced Morphological Changes In Dual Ph And Temperature Responsive Ultra-Low Crosslinked Poly (N-Isopropyl Acrylamide)-Co-Acrylic Acid Microgels, Molla R. Islam, Maddie Tumbarello, L. Andrew Lyon

Engineering Faculty Articles and Research

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Poly(N-isopropylacrylamide) microgels prepared without exogenous cross-linker are extremely “soft” as a result of their very low cross-linking density, with network connectivity arising only from the self-crosslinking of pNIPAm chains. As a result of this extreme softness, our group and others have taken interest in using these materials in a variety of bioengineering applications, while also pursuing studies of their fundamental properties. Here, we report deswelling triggered structural changes in poly(N-isopropylacrylamide-co-acrylic acid) (ULC10AAc) microgels prepared by precipitation polymerization. Dynamic light scattering suggests that the deswelling of these particles not only depends on the collapse of …

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