Stimuli-responsive microgels with cationic moieties: characterization and interaction with <i>E. coli</i> cells

Hussmann, Larissa; Belthle, Thomke; Demco, Dan E.; Fechete, Radu; Pich, Andrij

doi:10.1039/d1sm01007g

Cited by 10 publications

(47 citation statements)

References 50 publications

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“…37,38 The width of temperature-induced volume-phase transition is related to the transition temperature and change of entropy between swollen and collapsed states of the microgels by relation ΔT t j = k B T t j /|ΔS j |. 15 Flory−Rehner Theory and Entropy Change. The temperature-induced volume-phase transition of thermoresponsive microgels is described by the Flory−Rehner theory that can be applied to systems with homogeneous 39,40 and heterogeneous morphologies.…”

Section: O Tmentioning

confidence: 98%

“…The related theoretical models are presented in the following. 15 Microgel Volume-Phase Transition of Functional Groups by the Boltzmann Function Approach. The temperature-induced volume-phase transition of microgels can be described using the phenomenological Boltzmann sigmoidal function (see eq 2).…”

Section: ■ Theorymentioning

confidence: 99%

“…To broaden the application area for permanently charged microgels, a deeper investigation of the polymer network properties and their dependence on the physical and chemical stimuli is required. Recently, this was achieved by our group 15 by characterization of the temperature-induced volume-phase transition and spatial distribution of neutral and charged moieties in poly(VCL-VIM + ) microgels for the rational design of functional microgels. 1 H high-resolution NMR spectroscopy in combination with transverse (T 2 ) magnetization relaxometry allows for a separate investigation of the behavior of each functional group in the polymer network, e.g., VCL and VIM + .…”

Section: ■ Introductionmentioning

confidence: 99%

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Nanostructuring the Interior of Stimuli-Responsive Microgels by N-Vinylimidazoles Quaternized with Hydrophobic Alkyl Chains

2022

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The functionality of stimuli-responsive microgels can be tailor-made by manipulating their internal nanostructure induced by the chemical composition and morphology of the polymer network. Microgels with phase-separated domains on a nanoscopic length scale were synthesized by copolymerization of N-vinylcaprolactam (VCL) and amphiphilic-to-hydrophobic 1-vinyl-3-alkylimidazolium (VIM+C n H2n+1) bromides (Br–) of different alkyl chain lengths (n = 12, 14, 16) as comonomers. These quaternized imidazoles provide dual functionality for immobilization of payload by electrostatic and hydrophobic interactions. The morphologies and properties of synthesized poly(VCL-co-VIM+C n H2n+1Br–) microgels with 10 mol % comonomer were investigated systematically by 1H and 13C high-resolution NMR spectroscopy and relaxometry. Chemical side-selective information about the monomers’ volume-phase transition temperatures, width of transition, and change in transition entropy was reported and correlated to the alkyl chain length of the VIM+C n H2n+1Br– comonomer. 13C NMR spectroscopy reveals the existence of trans and gauche conformers of alkyl chains, which depends on the alkyl chain length and temperature. Morphologies and dynamic contrasts of alkyl chain domains and VCL moieties of poly(VCL-co-VIM+C n H2n+1Br–) microgels were investigated by 1H transverse magnetization relaxation (T 2-relaxation). Finally, the microgels were successfully applied in the uptake of the hydrophobic dye Nile red, proving their ability to solubilize hydrophobic substances. In addition, the poly(VCL-co-VIM+C n H2n+1Br–) microgels were utilized in electrostatic interactions, as well as simultaneous addition of hydrophobic and negatively charged payload as a proof of concept for dual functionality. This investigation will allow for a better understanding of the internal nanophase structure of complex poly(N-vinylcaprolactam) (PVCL)-based microgels comprising pH-independent positive charges, as well as hydrophobic compartments, which have potential application as dual-functional delivery systems.

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Section: O Tmentioning

confidence: 98%

Section: ■ Theorymentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Nanostructuring the Interior of Stimuli-Responsive Microgels by N-Vinylimidazoles Quaternized with Hydrophobic Alkyl Chains

2022

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“…While the positive charge of such quaternary ammonium compounds (QACs) can be used for electrostatic interactions, e.g. for loading of oppositely charged payload, 2 or as antimicrobial agents, 61 the hydrophobic alkyl chain can enable the uptake of hydrophobic drugs such as triclosan. 28,29 Zu et al obtained microgels of similar size without visible nano-domains, as presented by TEM images (Fig.…”

Section: Microgel Network Comprising Hydrophobic Functional Groupsmentioning

confidence: 99%

“…The positive charges resulted in restricted temperature responsiveness due to the present electrostatic repulsion similar to that reported for C 1 vinylimidazolium-functionalized microgel systems. 61 In addition, the microgel functionalized with hydrophobic C 12 alkyl chains showed a shift of the volume phase transition temperature (VPTT) and a decreased swelling ability compared with C 1 . Interestingly, only the microgel sample with long alkyl chains (C 12 ) provided an antimicrobial activity against the tested Gram-positive bacteria S. aureus and S. epidermidis , revealing the need for not only positive charges but also hydrophobic chains for sufficient biocidal efficacy.…”

Section: Microgel Network Comprising Hydrophobic Functional Groupsmentioning

confidence: 99%

Aqueous microgels with engineered hydrophobic nano-domains

Belthle

Pich

2022

Mol. Syst. Des. Eng.

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Hexyl Gallate Loaded Microgels Enable Efficient Protection Against Citrus Canker

Braun,

Dilarri,

de Lencastre Novaes

et al. 2023

Adv Funct Materials

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The development of efficient and environmentally friendly plant protection systems is one of the major challenges for a sustainable agriculture of the future. Citrus canker caused by the pathogen Xanthomonas citri subsp. citri (X. citri) affects all cultivated citrus species worldwide and is responsible for enormous economic losses and restrictions in international trade. Currently used commercial copper‐based formulations are the origin of contamination for soil and groundwater, affecting local ecosystems and human health. A copper‐free sustainable microgel‐based plant protection system able to efficiently combat X. citri is developed. Microgels decorated with anchor peptides exhibit strong non‐covalent attachment to the surface of orange leaves and have the ability to release hexyl gallate, which inhibits the growth and spreading of pathogens. The tailored design of the microgel network allows high loadings of hexyl gallate (up to 40 wt.%) and a controlled release of gallates from microgels that provide long‐term protection. The antibacterial activity of the hexyl gallate‐loaded microgels is demonstrated by various in vitro assays as well as on orange plants in greenhouse settings. The experimental results suggest that the developed sustainable microgel‐based plant protection system for citrus trees allows efficient abatement of X. citri and reduces environmental pollution caused by copper formulations.

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Stimuli-responsive microgels with cationic moieties: characterization and interaction with E. coli cells

Abstract: Poly-N-vinylcaprolactam based microgels with positively charged 1-vinyl-3-methylimidazolium were analyzed by functional group volume phase transitions and morphology. The microgels are antibacterial, due to positive charges in the microgel corona.

Cited by 10 publications

References 50 publications

Nanostructuring the Interior of Stimuli-Responsive Microgels by N-Vinylimidazoles Quaternized with Hydrophobic Alkyl Chains

Nanostructuring the Interior of Stimuli-Responsive Microgels by N-Vinylimidazoles Quaternized with Hydrophobic Alkyl Chains

Aqueous microgels with engineered hydrophobic nano-domains

Hexyl Gallate Loaded Microgels Enable Efficient Protection Against Citrus Canker

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