Surface Chemical and Mechanical Properties of Plasma-Polymerized <i>N</i>-Isopropylacrylamide

Cheng, Xuanhong; Canavan, Heather E.; Stein, M.; Hull, James R.; Kweskin, Sasha; Wagner, Mary B.; Somorjai, Gábor A.; Castner, David G.; Ratner, Buddy D.

doi:10.1021/la050417o

Cited by 173 publications

(183 citation statements)

References 74 publications

(149 reference statements)

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“…5 corresponding to Figure 8). At low temperatures the stiffness of both microgels is equal and confirm the previous elasticity measurements on PNIPAM films [28]. The periphery morphology for both microgels should be equal resulting in the same Young's modulus.…”

Section: Elasticity Measurementssupporting

confidence: 88%

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

et al. 2011

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Abstract:The swelling/deswelling behaviour of microgel particles in the bulk and at the surface was studied and correlated to their mechanical properties. We focused on two kinds of particles: pure PNIPAM and PNIPAM-co-AAc particles. It was shown that the two step volume phase transition found for PNIPAM-co-AAc particles in the bulk disappears after the adsorption at the surface and only a one step transition was identified. The transition temperature increased strongly with increasing the co-monomer content. The dependence of the Young's modulus of the adsorbed microgel particles on the temperature and the co-monomer content was discussed. The investigations were performed via DLS and SFM.

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Section: Elasticity Measurementssupporting

confidence: 88%

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

et al. 2011

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“…When it is immobilized on a substrate, the chain conformational change leads to transitions in surface wettability 9,10 and chemistry. 11 Since both factors affect protein behavior on a surface, [12][13][14] it is expected that the amount of adsorbed proteins as well as the affinity, activity and conformation/orientation of the adsorbed protein layer will vary as the polymer is cycled through its lower critical solution temperature ͑LCST͒.…”

Section: Introductionmentioning

confidence: 99%

Temperature dependent activity and structure of adsorbed proteins on plasma polymerized N-isopropyl acrylamide

et al. 2006

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Thorough studies of protein interactions with stimulus responsive polymers are necessary to provide a better understanding of their applications in biosensors and biomaterials. In this study, protein behavior on a thermoresponsive polymer surface, plasma polymerized N-isopropyl acrylamide (ppNIPAM), is investigated using multiple characterization techniques above and below its lower critical solution temperature (LCST). Protein adsorption and binding affinity are probed using radiolabeled proteins. Protein activity is estimated by measuring the immunological activity of an antibody adsorbed onto ppNIPAM using surface plasmon resonance. Conformation/orientation of the proteins is probed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and principal component analysis (PCA) of the TOF-SIMS data. In this work, we find that at low protein solution concentrations, ppNIPAM-treated surfaces are low fouling below the LCST, but protein retentive above it. The protein adsorption isotherms demonstrate that apparent affinity between soluble protein molecules and the ppNIPAM surface are an order of magnitude lower at room temperature than at 37 °C. Although direct protein desorption is not observed in our study when the surface temperature drops below the LCST, the binding affinity of surface adsorbed protein with ppNIPAM is reduced, as judged by a detergent elution test. Furthermore, we demonstrated that proteins adsorbed onto ppNIPAM are functionally active, but the activity is better preserved at room temperature than 37 °C. The temperature dependent difference in protein activity as well as TOF-SIMS and PCA study suggest that proteins take different conformations/orientations after adsorption on ppNIPAM above and below the LCST.

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“…This property as well as the sharp phase transition and close proximity of the LCST to physiological temperature make pNIPAM attractive for application in biomedical and biotechnological devices. One of the most popular examples of the application of stimuli responsive materials is the use of pNIPAM in cell sheet engineering [23,[26][27][28]. In this technique cells may be grown to confluency on pNIPAM surfaces at temperatures above the LCST and then released as an intact sheet by lowering the temperature below the LCST [12,22,26].…”

Section: Introductionmentioning

confidence: 99%

Switchable surface coatings for control over protein adsorption

Cole

Jasieniak

Voelcker

et al. 2006

Biomedical Applications of Micro- And Nanoengineering III

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Control over biomolecule interactions at interfaces is becoming an increasingly important goal for a range of scientific fields and is being intensively studied in areas of biotechnological, biomedical and materials science. Improvement in the control over materials and biomolecules is particularly important to applications such as arrays, biosensors, tissue engineering, drug delivery and 'lab on a chip' devices. Further development of these devices is expected to be achieved with thin coatings of stimuli responsive materials that can have their chemical properties 'switched' or tuned to stimulate a certain biological response such as adsorptionldesorption of proteins. Switchable coatings show great potential for the realisation of spatial and temporal immobilisation of cells and biomolecules such as DNA and proteins.This study focuses on protein adsorption onto coatings of the thermosensitive polymer poly(N-isopropylacrylamide) (pNIPAM) which can exhibit low and high protein adsorption properties based on its temperature dependent conformation. At temperatures above its lower critical solution temperature (LCST) pNIPAM polymer chains are collapsed and protein adsorbing whilst below the LCST they are hydrated and protein repellent. Coatings of pNIPAM on silicon wafers were prepared by free radical polymerisation in the presence of surface bound polymerisable groups. Surface analysis and protein adsorption was carried out using X-ray photoelectron spectroscopy, time of flight secondary ion mass spectrometry and contact angle measurements. This study is expected to aid the development of stimuli-responsive coatings for biochips and biodevices.

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Surface Chemical and Mechanical Properties of Plasma-Polymerized N-Isopropylacrylamide

Cited by 173 publications

References 74 publications

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

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

Temperature dependent activity and structure of adsorbed proteins on plasma polymerized N-isopropyl acrylamide

Switchable surface coatings for control over protein adsorption

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