The Effect of Co-Monomer Content on the Swelling/Shrinking and Mechanical Behaviour of Individually Adsorbed PNIPAM Microgel Particles

Burmistrova, Anna; Richter, M.; Eisele, Michael; Üzüm, Çağrı; Klitzing, Regine von

doi:10.3390/polym3041575

Cited by 125 publications

(125 citation statements)

References 30 publications

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“…Previous studies have shown that the addition of hydrophilic co-monomers to poly(NIPAm) results in decreased temperature sensitivity of the resulting nanoparticles as the charged groups serve to increase overall solubility and resist the temperature-induced hydrophobic collapse (39,52,53). The addition of multiple hydrophilic groups to the backbone of our particles presents a possibility that their temperature sensitivity could be reduced to the extent that they are no longer a viable mechanism of controlled drug loading and release.…”

Section: Discussionmentioning

confidence: 97%

Prevention of Collagen-Induced Platelet Binding and Activation by Thermosensitive Nanoparticles

McMasters

Panitch

2015

AAPS J

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ABSTRACT. Peripheral artery disease is an atherosclerotic occlusion in the peripheral vasculature that is typically treated via percutaneous transluminal angioplasty. Unfortunately, deployment of the angioplasty balloon damages the endothelial layer, exposing the underlying collagen and allowing for the binding and activation of circulating platelets, which initiate an inflammatory cascade leading to eventual restenosis. Here, we report on the development of poly(NIPAm-MBA-AMPS-AAc) nanoparticles that have a collagen I-binding peptide crosslinked to their surface allowing them to bind to exposed collagen. Once bound, these particles mask the exposed collagen from circulating platelets, effectively reducing collagen-mediated platelet activation. Using collagen I-coated plates, we demonstrate that these particles are able to bind to collagen at concentrations above 0.5 mg/mL. Once bound, these particles inhibit collagen-mediated platelet activation by over 60%. Using light scattering and zeta potential measurements, we investigated the potential of the nanoparticles as a drug delivery platform. We have verified that the collagen-binding nanoparticles retain the temperature sensitivity common to poly(NIPAm)-based nanoparticles while remaining colloidally stable in aqueous environments. We also demonstrate that they are able to passively load and release anti-inflammatory cell penetrating peptides. Combined, we have developed a collagen-binding nanoparticle that has dual therapy potential, preventing collagen-mediated platelet activation while delivering water-soluble therapeutics directly to the damaged area.

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Section: Discussionmentioning

confidence: 97%

Prevention of Collagen-Induced Platelet Binding and Activation by Thermosensitive Nanoparticles

McMasters

Panitch

2015

AAPS J

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“…This is explained by microphase separation into pure PNIPAM domains and PNIPAM-co-AAc domains, which exhibit different VPTT. At the surface, such domains interfere with each other due to compression leading to an averaged VPTT [26]. The question arises, whether a geometrical confinement, like a planar surface, might affect the cononsolvency behavior.…”

Section: Introductionmentioning

confidence: 99%

The impact of the cononsolvency effect on poly (N-isopropylacrylamide) based microgels at interfaces

2014

Self Cite

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The paper addresses the effect of solid interfaces on the cononsolvency effect for poly(N -iso propylacrylamide) based microgels containing different contents of the co-monomer allyl acetic acid (AAA). The cononsolvency effect is studied by dynamic light scattering (DLS) in solution and with atomic force microscopy (AFM) at surfaces against different mixtures of water and organic solvent (ethanol, iso-propanol, and tetrahydrofuran). For the studies at interfaces, the microgels are spin coated on silicon wafers that are precoated with poly(allylamine hydrochloride) (PAH). The minimum in particle volume due to cononsolvency shows a pronounced shift from 10-20 % of organic solvent to 40-50 % after deposition at the Si/PAH wafer. The strong shift indicates an increase of water to organic solvent ratio within the gel at the surface with respect to the bulk solution. In order to understand the increase of water to organic solvent ratio, shrinking/reswelling AFM experiments for different spincoating conditions and under ambient conditions are carried out. Spin coating from water instead from different solvent mixtures has no effect on the cononsolvency. In ambient conditions, the cononsolvency effect disappears

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“…Due to the soft nature of the HA/PLL films, the microgels might be spontaneously immersed into the film. The increase in detected width above VPTT might be due to an increase in the elastic modulus of the microgel from about 100 kPa to about 800 kPa, 46,69 which makes the detection of microgels easier by using the AFM. The value of Young's modulus of the surrounding HA/PLL film is in the range of tens of kPa.…”

Section: Molecular Transport Through Mg-coated Ha/pll Filmsmentioning

confidence: 99%

“…44,45 Poly(N-isopropylacrylamide) (PNIPAM) is one of the most well-known temperature sensitive polymers applied for the synthesis of macrogels and microgels (MG). [46][47][48][49] At the volume phase transition temperature (VPTT at 32-34 1C) PNIPAM chains undergo a reversible volume phase transition (VPT) mainly due to intramolecular hydrophobic interactions resulting in the release of bound water molecules and a pronounced volume reduction. [50][51][52][53][54] The advantage of microgels vs. macrogels is that microgels react much faster to external stimuli (here: changes in temperature) than macrogels and they can be easily processed for film formation compared to macrogels.…”

Section: Introductionmentioning

confidence: 99%

Temperature-induced molecular transport through polymer multilayers coated with PNIPAM microgels

Vikulina

Aleed

Paulraj

et al. 2015

Phys. Chem. Chem. Phys.

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Polyelectrolyte multilayers serve as effective reservoirs for bioactive molecules which are stored and released from the multilayers for cellular applications. However, control over the release without significantly affecting the multilayers and biomolecules is still a challenge. On the other hand, externally stimulated release would make the multilayers promising for the development of stimuli-sensitive planar carriers with release performance switched on demand. In this study soft composite films are designed by coating hyaluronic acid/poly-L-lysine (HA/PLL) multilayers with temperature responsive poly-(N-isopropylacrylamide) (PNIPAM) microgels. Microgels are flattened and immersed into the multilayers to maximize the number of contacts with the surrounding polyelectrolytes (HA and PLL). The microgel coating serves as an efficient switchable barrier for the PLL transport into the multilayers. PLL diffusion into the film is significantly hindered at room temperature but is dramatically enhanced at 40 1C above the volume phase transition temperature (VPTT) of PNIPAM at 32 1C associated with microgel shrinkage. Scanning force microscopy micrographs show that the mechanism of volume phase transition on soft surfaces cannot be directly deduced from the processes taking place at solid substrates.

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The Effect of Co-Monomer Content on the Swelling/Shrinking and Mechanical Behaviour of Individually Adsorbed PNIPAM Microgel Particles

Cited by 125 publications

References 30 publications

Prevention of Collagen-Induced Platelet Binding and Activation by Thermosensitive Nanoparticles

Prevention of Collagen-Induced Platelet Binding and Activation by Thermosensitive Nanoparticles

The impact of the cononsolvency effect on poly (N-isopropylacrylamide) based microgels at interfaces

Temperature-induced molecular transport through polymer multilayers coated with PNIPAM microgels

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