Chemical-Physical Behaviour of Microgels Made of Interpenetrating Polymer Networks of PNIPAM and Poly(acrylic Acid)

Nigro, Valentina; Angelini, Roberta; Bertoldo, Monica; Buratti, Elena; Franco, Silvia; Ruzicka, Barbara

doi:10.3390/polym13091353

Cited by 20 publications

(15 citation statements)

References 104 publications

(185 reference statements)

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“…It is also worth noting that the transition is sharper in D 2 O than in H 2 O for both h-P m and d-P m , as can be seen from the peak broadness of the derivative, that is especially narrow for the non-deuterated polymer in D 2 O. This is in good agreement with other works on PNIPAM-based materials [65,66,44,67]. The shape of the transition for h-P m and d-P m in H 2 O is instead almost identical.…”

Section: Swelling Behaviour Of Pnipam Microgelssupporting

confidence: 91%

The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions

Buratti¹,

Tavagnacco²,

Zanatta³

et al. 2022

Preprint

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Poly(N -isopropylacrylamide) (PNIPAM) is a synthetic polymer that is widely studied for its thermoresponsive character. However, recent works also reported evidence of a low temperature (protein-like) dynamical transition around 225 K in concentrated PNIPAM suspensions, independently of the polymer architecture, i.e., both for linear chains and for microgels. In this work, we investigate water-polymer interactions by extensive differential scanning calorimetry (DSC) measurements of both systems, in order to understand the effect of the different topological structures on the solution behaviour, in particular regarding crystallization and melting processes. In addition, we compare protiated and deuterated microgels, in both water and deuterated water. The DSC results are complemented by dynamic light scattering experiments, which confirm that the selective isotopic substitution differently affects the solution behaviour. Our findings highlight the important role played by the polymer architecture on the solution behaviour: indeed, microgels turn out to be more efficient confining agents, able to avoid water crystallization in a wider concentration range with respect to linear chains.

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Section: Swelling Behaviour Of Pnipam Microgelssupporting

confidence: 91%

The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions

Buratti¹,

Tavagnacco²,

Zanatta³

et al. 2022

Preprint

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“…Temperatures lower than the VPTT cause the polymer, forming the microgel, to swell up with the water. Temperatures higher than VPTT will result in causing the polymer to shrink [ 26 , 27 ] and release the encapsulated drug. Thermosensitive micro/nanogels response to the change in temperature is generally through reversible disruption of the hydrogen bonds located between the polymer and the surrounding water [ 28 ].…”

Section: Thermosensitive Polymersmentioning

confidence: 99%

Thermosensitive Polymers and Thermo-Responsive Liposomal Drug Delivery Systems

et al. 2022

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Temperature excursions within a biological milieu can be effectively used to induce drug release from thermosensitive drug-encapsulating nanoparticles. Oncological hyperthermia is of particular interest, as it is proven to synergistically act to arrest tumor growth when combined with optimally-designed smart drug delivery systems (DDSs). Thermoresponsive DDSs aid in making the drugs more bioavailable, enhance the therapeutic index and pharmacokinetic trends, and provide the spatial placement and temporal delivery of the drug into localized anatomical sites. This paper reviews the fundamentals of thermosensitive polymers, with a particular focus on thermoresponsive liposomal-based drug delivery systems.

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“…Smart microgels have emerged as promising materials in numerous biomedical applications, such as biosensing, drug delivery, and enzyme encapsulation because of their unique characteristic features. − They are soft colloidal particles composed of a gel-like internal structure with a size typically ranging between tens of nanometers and submicrons. − Poly( N -isopropylacrylamide) (PNIPAM) is a most commonly studied thermoresponsive microgel, which exhibits a volume phase transition temperature (VPTT) at around 32 °C owing to its sharp swollen-to-collapsed phase transition. ,,, Microgel can be made pH-responsive by introducing charged functionality − or through an interpenetrated polymer network. , Incorporation of charged units leads to a higher swelling degree of the microgels, allowing oppositely charged counterions, polyelectrolytes, proteins, enzymes, etc. − to adsorb strongly onto the particles. Because of the responsive nature, the microgels have been used in the controlled release of drugs. − ,, The drug release can be triggered by external stimuli through which the microgels undergo structural change …”

Section: Introductionmentioning

confidence: 99%

Chitosan Hydrogels with Embedded Thermo- and pH-Responsive Microgels as a Potential Carrier for Controlled Release of Drugs

Singh

Aery

Juneja

et al. 2022

ACS Appl. Bio Mater.

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We report a promising strategy based on chitosan (CS) hydrogels and dual temperature- and pH-responsive poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-co-MAA) microgels to facilitate release of a model drug, moxifloxacin (MFX). In this protocol, first, the microgels were prepared using a free radical copolymerization method, and subsequently, these carboxyl-group-rich soft particles were incorporated inside the hydrogel matrix using an EDC-NHS amidation method. Interestingly, the resulting microgel-embedded hydrogel composites (MG-HG) acting as a double barrier system largely reduced the drug release rate and prolonged the delivery time for up to 68 h, which was significantly longer than that obtained using microgels or hydrogels alone (20 h). On account of the dual-responsive features of the embedded microgels and the variation of water-solubility of drug molecules as a function of pH, MFX could be released in a controllable manner by regulating the temperature and pH of the delivery medium. The release kinetics followed a Korsmeyer-Peppas model, and the drug delivery mechanism was described by Fickian diffusion. Both the gel precursors and the hydrogel composites exhibited low cytotoxicity against mammalian cell lines (HeLa and HEK-293) and no deleterious hemolytic activity up to a certain higher concentration, indicating excellent biocompatibility of the materials. Thus, the unprecedented combination of modularity of physical properties caused by soft particle entrapment, unique macromolecular architecture, biocompatibility, and the general utility of the stimuli-responsive polymers offers a great promise to use these composite materials in drug delivery applications.

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Chemical-Physical Behaviour of Microgels Made of Interpenetrating Polymer Networks of PNIPAM and Poly(acrylic Acid)

Cited by 20 publications

References 104 publications

The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions

The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions

Thermosensitive Polymers and Thermo-Responsive Liposomal Drug Delivery Systems

Chitosan Hydrogels with Embedded Thermo- and pH-Responsive Microgels as a Potential Carrier for Controlled Release of Drugs

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