Editorial

2 pages, 187 KiB

Open AccessEditorial

by Zachary J. Rogers and Sidi A. Bencherif

Gels 2019, 5(4), 46; https://doi.org/10.3390/gels5040046 - 03 Dec 2019

Cited by 26 | Viewed by 22035

Cryogenic processes are increasingly being utilized to create unique polymeric materials that tackle challenges mainly in the biomedical arena, environmental science, and field of food technology [...] Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

Research

Jump to: Editorial, Review

13 pages, 2968 KiB

Open AccessArticle

Poly(Hydroxyethyl Methacrylate) Immunoaffinity Cryogel Column for the Purification of Human Immunoglobulin M

by Monireh Bakhshpour, Aykut Arif Topcu, Nilay Bereli, Huseyin Alkan and Adil Denizli

Gels 2020, 6(1), 4; https://doi.org/10.3390/gels6010004 - 29 Jan 2020

Cited by 12 | Viewed by 3356

Abstract

Human immunoglobulin M (hIgM) antibodies are considered as hopeful tools for diseases therapy. Therefore, chromatography approaches are used to purify hIgM with a single step. In this study, we prepared a poly(hydroxyethyl methacrylate) based immunoaffinity p(HEMA-I) cryogel column by using cyanamide to immobilize [...] Read more.

Human immunoglobulin M (hIgM) antibodies are considered as hopeful tools for diseases therapy. Therefore, chromatography approaches are used to purify hIgM with a single step. In this study, we prepared a poly(hydroxyethyl methacrylate) based immunoaffinity p(HEMA-I) cryogel column by using cyanamide to immobilize antihuman immunoglobulin on the p(HEMA) cryogel for purification of hIgM in aqueous solution and artificial human plasma. The characterization of the p(HEMA) cryogel column was performed by using a scanning electron microscope (SEM), micro-computerized tomography (µ-CT), Fourier transform infrared spectroscopy (FTIR), swelling degree and macro-porosity. Further, the optimizations of various parameters were performed such as, pH, ionic strength, temperature and concentration of hIgM in aqueous solutions. In addition, the Langmuir adsorption model was supported by experimental results. Maximum adsorbed amount of hIgM corresponded to 11.1 mg/g at pH 5.75 [morpholino ethanesulfonic acid (MES buffer)]. Our results indicated that the p(HEMA-I) cryogel column can be reused at least 10 times without significant loss in adsorption capacity. As a natural source, artificial human plasma was selected for hIgM adsorption and the purity of hIgM was evaluated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Graphical abstract

15 pages, 3782 KiB

Open AccessArticle

Cryostructuring of Polymeric Systems. 52. Properties, Microstructure and an Example of a Potential Biomedical Use of the Wide-Pore Alginate Cryostructurates

by Natalia D. Zvukova, Tamara P. Klimova, Roman V. Ivanov, Andrei N. Ryabev, Archil V. Tsiskarashvili and Vladimir I. Lozinsky

Gels 2019, 5(2), 25; https://doi.org/10.3390/gels5020025 - 09 May 2019

Cited by 5 | Viewed by 6541

Abstract

Wide-pore cryostructurates were prepared via freezing sodium alginate aqueous solutions with subsequent ice sublimation from the frozen samples, followed by their incubation in the ethanol solutions of calcium chloride or sulfuric acid, rinsing, and final drying. Such sequence of operations resulted in the [...] Read more.

Wide-pore cryostructurates were prepared via freezing sodium alginate aqueous solutions with subsequent ice sublimation from the frozen samples, followed by their incubation in the ethanol solutions of calcium chloride or sulfuric acid, rinsing, and final drying. Such sequence of operations resulted in the calcium alginate or alginic acid sponges, respectively. The swelling degree of the walls of macropores in such matrices decreased with increasing polymer concentration in the initial solution. The dependence of the degree of swelling on the cryogenic processing temperature had a bell-like character with a maximum for the samples formed at −20 °C. According to ¹H NMR spectroscopy, the content of mobile (non-frozen) water in the frozen water-sodium alginate systems also depended on the initial polymer concentration and freezing temperature. The cryostructurates obtained did not lose their integrity in water, saline, in an acidic medium at pH 2 for at least three weeks. Under alkaline conditions at pH 12 the first signs of dissolution of the Ca-alginate sponge arose only after a week of incubation. Microbiological testing of the model depot form of the antibiotics entrapped in the Ca-alginate cryostructurate demonstrated the efficiency of this system as the antibacterial material. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Figure 1

16 pages, 4924 KiB

Open AccessArticle

Investigating Manuka Honey Antibacterial Properties When Incorporated into Cryogel, Hydrogel, and Electrospun Tissue Engineering Scaffolds

by Katherine R. Hixon, Savannah J. Bogner, Gabriela Ronning-Arnesen, Blythe E. Janowiak and Scott A. Sell

Gels 2019, 5(2), 21; https://doi.org/10.3390/gels5020021 - 18 Apr 2019

Cited by 32 | Viewed by 5484

Abstract

Honey is well-known for its wound healing capability and Manuka honey (MH) contains a unique Manuka factor, providing an additional antibacterial agent. Previously, there has not been a practical way to apply MH to a wound site, which renders treatment for an extended [...] Read more.

Honey is well-known for its wound healing capability and Manuka honey (MH) contains a unique Manuka factor, providing an additional antibacterial agent. Previously, there has not been a practical way to apply MH to a wound site, which renders treatment for an extended period extremely difficult. Tissue-engineered scaffolds offer an alternative treatment method to standard dressings by providing varying geometries to best treat the specific tissue. MH was incorporated into cryogels, hydrogels, and electrospun scaffolds to assess the effect of scaffold geometry on bacterial clearance and adhesion, as well as cellular adhesion. Electrospun scaffolds exhibited a faster release due to the nanoporous fibrous geometry which led to a larger partial bacterial clearance as compared to the more three-dimensional cryogels (CG) and hydrogels (HG). Similarly, the fast release of MH from the electrospun scaffolds resulted in reduced bacterial adhesion. Overall, the fast MH release of the electrospun scaffolds versus the extended release of the HG and CG scaffolds provides differences in cellular/bacterial adhesion and advantages for both short and long-term applications, respectively. This manuscript provides a comparison of the scaffold pore structures as well as bacterial and cellular properties, providing information regarding the relationship between varying scaffold geometry and MH efficacy. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Graphical abstract

14 pages, 5856 KiB

Open AccessEditor’s ChoiceArticle

Porous Starch Materials via Supercritical- and Freeze-Drying

by Victor Baudron, Pavel Gurikov, Irina Smirnova and Steve Whitehouse

Gels 2019, 5(1), 12; https://doi.org/10.3390/gels5010012 - 26 Feb 2019

Cited by 64 | Viewed by 8670

Abstract

The production of porous materials based on starch has been explored with supercritical drying—yielding aerogel—and freeze-drying. The two drying procedures were applied on the same gelling solution of amylomaize starch pasted at 140 °C and for two concentrations (5 and 10 wt.%). After [...] Read more.

The production of porous materials based on starch has been explored with supercritical drying—yielding aerogel—and freeze-drying. The two drying procedures were applied on the same gelling solution of amylomaize starch pasted at 140 °C and for two concentrations (5 and 10 wt.%). After gelation and retrogradation, water from the samples to be supercritically dried was exchanged to ethanol. The resulting starch aerogel presented high specific surface area (197 m²/g). Freeze-drying was assessed by investigating the effect of the gelation, retrogradation, freezing temperature, and sublimation pressure. The resulting starch materials were macroporous, with limited specific surface area and limited mechanical integrity. Cohesive open cell foam with pore size of ~20 µm was produced by quenching the hot starch melt in liquid nitrogen. The highest specific surface area obtained with freeze-drying was 7.7 m²/g for the hot starch melt frozen at −20 °C. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Graphical abstract

13 pages, 4436 KiB

Open AccessFeature PaperArticle

Highly Stretchable and Rapid Self-Recoverable Cryogels Based on Butyl Rubber as Reusable Sorbent

by Sevil Muslumova, Berkant Yetiskin and Oguz Okay

Gels 2019, 5(1), 1; https://doi.org/10.3390/gels5010001 - 07 Jan 2019

Cited by 18 | Viewed by 5584

Abstract

Cryogels based on hydrophobic polymers combining good mechanical properties with fast responsivity are attractive materials for many applications, such as oil spill removal from water and passive sampler for organic pollutants. We present, here, cryogels based on butyl rubber (BR) with a high [...] Read more.

Cryogels based on hydrophobic polymers combining good mechanical properties with fast responsivity are attractive materials for many applications, such as oil spill removal from water and passive sampler for organic pollutants. We present, here, cryogels based on butyl rubber (BR) with a high stretchability, rapid self-recoverability, and excellent reusability for organic solvents. BR cryogels were prepared at subzero temperatures in cyclohexane and benzene at various BR concentrations in the presence of sulfur monochloride (S₂Cl₂) as a crosslinker. Although the properties of BR cryogels are independent of the amount of the crosslinker above a critical value, the type of the solvent, the cryogelation temperature, as well as the rubber content significantly affect their properties. It was found that benzene produces larger pore volumes as compared to cyclohexane due to the phase separation of BR from benzene at low temperatures, producing additional pores. Increasing cryogelation temperature from −18 to −2 °C leads to the formation of more ordered and aligned pores in the cryogels. Increasing BR content decreases the amount of unfrozen microphase of the frozen reaction solution, leading to a decrease in the total porosity of the cryogels and the average diameter of pores. Cryogels formed at −2 °C and at 5% (w/v) BR in cyclohexane sustain up to around 1400% stretch ratios. Cryogels swollen in toluene can completely be squeezed under strain during which toluene is released from their pores, whereas addition of toluene to the squeezed cryogels leads to recovery of their original shapes. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Graphical abstract

18 pages, 4014 KiB

Open AccessFeature PaperArticle

Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO

by Vladimir I. Lozinsky, Olga Yu. Kolosova, Dmitrii A. Michurov, Alexander S. Dubovik, Viktor G. Vasil’ev and Valerij Ya. Grinberg

Gels 2018, 4(4), 81; https://doi.org/10.3390/gels4040081 - 08 Oct 2018

Cited by 12 | Viewed by 6159

Abstract

Urea (URE) and guanidine hydrochloride (GHC) possessing strong chaotropic properties in aqueous media were added to DMSO solutions of poly(vinyl alcohol) (PVA) to be gelled via freeze–thaw processing. Unexpectedly, it turned out that in the case of the PVA cryotropic gel formation in [...] Read more.

Urea (URE) and guanidine hydrochloride (GHC) possessing strong chaotropic properties in aqueous media were added to DMSO solutions of poly(vinyl alcohol) (PVA) to be gelled via freeze–thaw processing. Unexpectedly, it turned out that in the case of the PVA cryotropic gel formation in DMSO medium, the URE and GHC additives caused the opposite effects to those observed in water, i.e., the formation of the PVA cryogels (PVACGs) was strengthened rather than inhibited. Our studies of this phenomenon showed that such “kosmotropic-like” effects were more pronounced for the PVACGs that were formed in DMSO in the presence of URE additives, with the effects being concentration-dependent. The additives also caused significant changes in the macroporous morphology of the cryogels; the commonly observed trend was a decrease in the structural regularity of the additive-containing samples compared to the additive-free gel sample. The viscosity measurements revealed consistent changes in the intrinsic viscosity, Huggins constant, and the excess activation heat of the viscosity caused by the additives. The results obtained evidently point to the urea-induced decrease in the solvation ability of DMSO with respect to PVA. As a result, this effect can be the key factor that is responsible for strengthening the structure formation upon the freeze–thaw gelation of this polymer in DMSO additionally containing additives such as urea, which is capable of competing with PVA for the solvent. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Figure 1

Review

Jump to: Editorial, Research

20 pages, 7399 KiB

Open AccessReview

Supermacroporous Composite Cryogels in Biomedical Applications

by Yeşeren Saylan and Adil Denizli

Gels 2019, 5(2), 20; https://doi.org/10.3390/gels5020020 - 17 Apr 2019

Cited by 66 | Viewed by 7074

Abstract

Supermacroporous gels, called cryogels, are unique scaffolds that can be prepared by polymerization of monomer solution under sub-zero temperatures. They are widely used in many applications and have significant potential biomaterials, especially for biomedical applications due to their inherent interconnected supermacroporous structures and [...] Read more.

Supermacroporous gels, called cryogels, are unique scaffolds that can be prepared by polymerization of monomer solution under sub-zero temperatures. They are widely used in many applications and have significant potential biomaterials, especially for biomedical applications due to their inherent interconnected supermacroporous structures and easy formation of composite polymers in comparison to other porous polymer synthesis techniques. This review highlights the fundamentals of supermacroporous cryogels and composite cryogels, and then comprehensively summarizes recent studies in preparation, functionalization, and utilization with mechanical, biological and physicochemical features, according to the biomedical applications. Furthermore, conclusions and outlooks are discussed for the use of these promising and durable supermacroporous composite cryogels. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Graphical abstract

22 pages, 10799 KiB

Open AccessEditor’s ChoiceReview

Physicochemical, Complexation and Catalytic Properties of Polyampholyte Cryogels

by Sarkyt E. Kudaibergenov

Gels 2019, 5(1), 8; https://doi.org/10.3390/gels5010008 - 21 Feb 2019

Cited by 27 | Viewed by 4399

Abstract

Polyampholyte cryogels are a less considered subject in comparison with cryogels based on nonionic, anionic and cationic precursors. This review is devoted to physicochemical behavior, complexation ability and catalytic properties of cryogels based on amphoteric macromolecules. Polyampholyte cryogels are able to exhibit the [...] Read more.

Polyampholyte cryogels are a less considered subject in comparison with cryogels based on nonionic, anionic and cationic precursors. This review is devoted to physicochemical behavior, complexation ability and catalytic properties of cryogels based on amphoteric macromolecules. Polyampholyte cryogels are able to exhibit the stimuli-responsive behavior and change the structure and morphology in response to temperature, pH of the medium, ionic strength and water–organic solvents. Moreover, they can uptake transition metal ions, anionic and cationic dyes, ionic surfactants, polyelectrolytes, proteins, and enzymes through formation of coordination bonds, hydrogen bonds, and electrostatic forces. The catalytic properties of polyampholyte cryogels themselves and with immobilized metal nanoparticles suspended are outlined following hydrolysis, transesterification, hydrogenation and oxidation reactions of various substrates. Application of polyampholyte cryogels as a protein-imprinted matrix for separation and purification of biomacromolecules and for sustained release of proteins is demonstrated. Comparative analysis of the behavior of polyampholyte cryogels with nonionic, anionic and cationic precursors is given together with concluding remarks. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Figure 1

12 pages, 823 KiB

Open AccessFeature PaperReview

Cryostructuring of Polymeric Systems. 50.^† Cryogels and Cryotropic Gel-Formation: Terms and Definitions

by Vladimir I. Lozinsky

Gels 2018, 4(3), 77; https://doi.org/10.3390/gels4030077 - 10 Sep 2018

Cited by 97 | Viewed by 8368

Abstract

A variety of cryogenically-structured polymeric materials are of significant scientific and applied interest in various areas. However, in spite of considerable attention to these materials and intensive elaboration of their new examples, as well as the impressive growth in the number of the [...] Read more.

A variety of cryogenically-structured polymeric materials are of significant scientific and applied interest in various areas. However, in spite of considerable attention to these materials and intensive elaboration of their new examples, as well as the impressive growth in the number of the publications and patents on this topic over the past two decades, a marked variability of the used terminology and definitions is frequently met with in the papers, reviews, theses, patents, conference presentations, advertising materials and so forth. Therefore, the aim of this brief communication is to specify the basic terms and definitions in the particular field of macromolecular science. Full article

(This article belongs to the Special Issue Cryogelation and Cryogels)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Cryogelation and Cryogels

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Related Special Issue

Published Papers (10 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI