UV-assisted synthesis of super-macroporous polymer hydrogels

Petrov, Petar; Petrova, Emilia; Tsvetanov, Christo B.

doi:10.1016/j.polymer.2008.12.039

Cited by 65 publications

(65 citation statements)

References 24 publications

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“…Petrov et al [117] synthesised polymer cryogels employing the UV irradiation technique and hydrogen peroxide as an initiator. Hydroxyethylcellulose and poly(N-isopropylacrylamide) (PNIPAAm) cryogels were characterised by a non-linear temperature dependence of the swelling degree ( Fig.…”

Section: Mpm (Fig 4a) and Clsm (mentioning

confidence: 99%

Cryogels: Morphological, structural and adsorption characterisation

Gun'ko

Savina

Mikhalovsky

2013

Advances in Colloid and Interface Science

281

205

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*Graphical Abstract (for review)Cryotripic gelation technique allows the synthesis of solid and soft macroporous gels Textural characterisation of cryogel in native superhydrated state with noninvasive methods Adsorption and diffusion characteristics of macroporous cryogels with respect to macromolecules and cells Theoretical modelling of adsorption from aqueous media *Highlights (for review) Please find the revised manuscript entitled "Cryogels: morphological, structural and adsorption characterisation" by Vladimir M. Gun'ko, Irina N. Savina, Sergey V. Mikhalovsky to re-consider for publication in the "Advances in Colloid and Interface Science"The paper was completely edited and changed according to reviewers comments.Sincerely yours, Prof. V. M. Gun'koCover Letter ABSTRACTExperimental results on polymer, protein, and composite cryogels and data treatment methods used for morphological, textural, structural, adsorption and diffusion characterisation of the materials are analysed and compared. Treatment of microscopic images with specific software gives quantitative structural information on both native cryogels and freeze-dried materials that is useful to analyse the drying effects on their structure. A combination of cryoporometry, relaxometry, thermoporometry, small angle X-ray scattering (SAXS), equilibrium and kinetic adsorption of low and high-molecular weight compounds, diffusion breakthrough of macromolecules within macroporous cryogel membranes, studying interactions of cells with cryogels provides a consistent and comprehensive picture of textural, structural and adsorption properties of a variety of cryogels. This analysis allows us to establish certain regularities in the cryogel properties related to narrow (diameter 0.4 < d < 2 nm), middle (2 < d < 50 nm) and broad (50 < d < 100 nm) nanopores, micropores (100 nm < d < 100 m) and macropores (d > 100 m) with boundary sizes within modified life science pore classification. Particular attention is paid to water bound in cryogels in native superhydrated or freeze-dried states. At least, five states of water -free unbound, weakly bound (changes in the Gibbs free energy G < 0.5-0.8 kJ/mol) and strongly bound (G > 0.8 kJ/mol), and weakly associated (chemical shift of the proton resonance  H = 1-2 ppm) and strongly associated ( H = 3-6 ppm) waters can be distinguished in hydrated cryogels using 1 H NMR, DSC, TSDC, TG and other methods. Different software for image treatment or developed to analyse the data obtained with the adsorption, diffusion, SAXS, cryoporometry and thermoporometry methods and based on regularisation algorithms is analysed and used for the quantitative morphological, structural and adsorption characterisation of individual and composite cryogels, including polymers filled with solid nano-or microparticles.

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Section: Mpm (Fig 4a) and Clsm (mentioning

confidence: 99%

Cryogels: Morphological, structural and adsorption characterisation

Gun'ko

Savina

Mikhalovsky

2013

Advances in Colloid and Interface Science

281

205

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“…As already mentioned, PNIPAAm is a temperature-responsive polymer and the cryo-and hydrogels obtained undergo a reversible volume phase transition from highly swollen to collapsed state at around 32 C. 18 In particular, PNIPAAm-CryoUrW decreased its apparent degree of swelling from 19 at …”

Section: Resultsmentioning

confidence: 86%

“…18 To embed the urease molecules predominantly into the cryogel walls, the enzyme was mixed with the aqueous solution of reagents prior freezing. It is known that in the process of cryostructuration the soluble substances are accumulated into a nonfrozen liquid microphase 20 where the formation of PNIPAAm network takes place upon irradiation with UV light.…”

Section: Resultsmentioning

confidence: 99%

“…To increase the response rate one may use the method of cryotropic gelation, where the system of large interconnected pores alleviates the temperature exchange. 18 This article aims at reporting on a novel and effective approach for enzyme immobilization, based on entrapment into the walls of poly(N-isopropylacrylamide) cryogels. The macroporous PNIPAAm cryogels possess chemical and biological stability, very good physicomechanical characteristics that provide high exploitation life of these materials.…”

Section: Introductionmentioning

confidence: 99%

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In situ entrapment of urease in cryogels of poly(N‐isopropylacrylamide): An effective strategy for noncovalent immobilization of enzymes

Petrov

Pavlova

Tsvetanov

et al. 2011

J of Applied Polymer Sci

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Supermacroporous poly(N-isopropylacrylamide) (PNIPAAm) cryogels containing urease were prepared via UV irradiation technique and hydrogen peroxide as initiator. Specifically, due to the cryostructuration phenomenon urease molecules were embedded into the dense cryogel walls. Thus, although the enzyme is physically entrapped, the system exhibited remarkable resistance against leaking due to the dense polymer network formed in the cryogel walls. The immobilized urease can catalyze the hydrolysis of urea in a broad temperature range in both batch and flow regime. The interconnected macropores assist for unhindered diffusion of the substrate and reaction products through the gel, thus, paving the way for consecutive reuse at a constant activity, in contrast to the conventional PNIPAAm hydrogel. Due to the spongy-like morphology PNIPAAm cryogels containing urease can be exploited as highly permeable membrane for direct removal of traces of urea from continuously flowing feed solutions.

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“…[19][20][21][22][23][24][25][26] Polyacrylamide gels are among the most commonly applied and well-studied hydrogel material systems due to their utility for high-resolution electrophoretic separation of proteins and DNA and more recently as cell culture substrates that provide physiologically relevant stiffnesses. [27] Hydrogels are polymeric networks, which absorb and retain large amounts of water. In the polymeric network hydrophilic groups or domains are present which are hydrated in an aqueous environment thereby creating the hydrogel structure.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization nanocomposite of polyacrylamide-rGO-Ag-PEDOT/PSS hydrogels by photo polymerization method

Lim

Singu

Hong

et al. 2015

Polym. Adv. Technol.

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We present a novel approach to the fabrication of advanced polymeric nanocomposite hydrogels from polyacrylamide (PAAm) by incorporation of graphene-silver-polyethylenedioxythiophene-polystyrene sulfonate (rGO-Ag-PEDOT/PSS) by photopolymerization method. Infrared spectroscopy was employed to characterize the structure of the hydrogels. The internal network structure of nanocomposite hydrogels was investigated by scanning electron microscope. Swelling, deswelling, and mechanical properties of the hydrogels were investigated. The compressive strength of nanocomposite hydrogels reaches maximum of 1.71 MPa when the ratio of rGO-Ag-PEDOT/PSS to PAAm was 0.3 wt%, which is 1.57 times higher than that of PAAm hydrogels (1.09 MPa). The electrical conductivity of the PAAm-rGO-Ag-PEDOT/PSS hydrogel was found to be 3.91 × 10 À5 S cm À1 .

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UV-assisted synthesis of super-macroporous polymer hydrogels

Cited by 65 publications

References 24 publications

Cryogels: Morphological, structural and adsorption characterisation

Cryogels: Morphological, structural and adsorption characterisation

In situ entrapment of urease in cryogels of poly(N‐isopropylacrylamide): An effective strategy for noncovalent immobilization of enzymes

Synthesis and characterization nanocomposite of polyacrylamide-rGO-Ag-PEDOT/PSS hydrogels by photo polymerization method

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