Photochemical Patterning of Ionically Cross-Linked Hydrogels

Bruchet, Marion; Mendelson, Nicole L.; Melman, Artem

doi:10.3390/pr1020153

Cited by 23 publications

(22 citation statements)

References 64 publications

(70 reference statements)

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“…To achieve loading of both biological cells and bioactive molecules, the internal structure of hydrogels has to be controlled on the scale of nano‐ and micrometers. Adjustment of the gel geometry has been demonstrated on substrate surfaces using different micropatterning techniques including a light‐addressable electrolytic system, electrodeposition, electrochemical patterning, or the benchtop method using Nylon mesh . The internal structure of alginate gels has been patterned with regular tube‐like pores, interconnected ordered honeycomb pores, and sponge‐like isotropic pores .…”

Section: Introductionmentioning

confidence: 99%

Design of Porous Alginate Hydrogels by Sacrificial CaCO₃ Templates: Pore Formation Mechanism

Sergeeva

Feoktistova

Prokopović

et al. 2015

Adv Materials Inter

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signifi cantly precise control over the scaffold architecture. Well-defi ned internal structure (porosity) determines both cellular infi ltration into the scaffold and its material properties. Pore size and distribution ensuring diffusion of nutrients into the scaffold and removal of metabolic products is of high importance. [ 4,11 ] Ionically crosslinked polymer gels such as alginate hydrogels have been extensively developed as scaffolds for tissue engineering. [12][13][14][15] The adjustable kinetics of the alginate gel degradation at neutral pH [ 1,16,17 ] gives an option to use the gels for multiple applications as wound dressings, anti-adhesive, and repair materials. [ 14,[18][19][20][21] Characteristics of alginate gels (hydration, softness, porosity, swelling in water, etc.) can be adjusted using a certain fabrication approach and by variation of interactions between charged polyanionic groups and crosslinking counterions; [ 13,17,[22][23][24][25] these interactions are known to be strongly affected by ionic strength, molecule length and structure, solvent pH, salt concentration, and temperature conditions. [26][27][28][29][30][31] This allows the fabrication of alginate scaffolds possessing desired properties corresponding to a certain tissue, for instance cartilage, [ 12 ] or dura mater. [ 21 ] Porous alginate gels can provide space and mechanical support to seed biological cells for tissue formation, [ 1,13,32 ] also allowing a controlled release of gel-laden drugs (peptides and proteins) trapped within the alginate network. [ 14,24,25,33,34 ] To achieve loading of both biological cells and bioactive molecules, the internal structure of hydrogels has to be controlled on the scale of nano-and micrometers. Adjustment of the gel geometry has been demonstrated on substrate surfaces using different micropatterning techniques including a light-addressable electrolytic system, [ 14 ] electrodeposition, [ 15 ] electrochemical patterning, [ 35 ] or the benchtop method using Nylon mesh. [ 11 ] The internal structure of alginate gels has been patterned with regular tube-like pores, [ 16,36 ] interconnected ordered honeycomb pores, [ 12 ] and sponge-like isotropic pores. [37][38][39] However, most of the approaches for alginate gel fabrication lack a precise control over the microstructure and require special equipment. Encapsulation of molecules of interest with controlled spatial distribution is rather complicated or even impossible. There is a need to develop a simple approach for design of a scaffold with welldefi ned internal structure providing both a space to culture cells and cavities to host/release encapsulated (bio)active molecules.Fabrication of porous alginate hydrogels with a well-controlled architecture useful for tissue engineering is still a challenge. Here, CaCO 3 -based templating is utilized to design stable alginate gels with controlled pore dimensions in the range of 5-50 µm. The mechanism of pore formation is studied considering two factors affecting the pore size: i) osmotic pressure generat...

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Section: Introductionmentioning

confidence: 99%

Design of Porous Alginate Hydrogels by Sacrificial CaCO₃ Templates: Pore Formation Mechanism

Sergeeva

Feoktistova

Prokopović

et al. 2015

Adv Materials Inter

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“…Using reductive cation exchange method bruchet treated iron (III) cross-linked alginate hydrogels with calcium salts and sodium ascorbate which resulted in the reduction of iron (III) to Iron (II) that were further replaced by Ca 2+ resulting in homogenous, patterned ionically cross-linked alginate hydrogels [116]. Another alternative method was chosen where the cation exchange was performed by the photochemical reduction in the presence of CaCl2 as a sacrificial photoreduction [117,118]. The likely hood of photochemical patterning of Iron (III) cross-linked hydrogel followed by the photochemical reductive exchange was demonstrated.…”

Section: Hydrogelsmentioning

confidence: 99%

Chemical Modifications of Alginate and Its Derivatives

Nataraj¹,

Reddy²

2020

Int J Chem Res

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Alginate is a polysaccharide obtained from seaweeds that are abundantly available and have shown great potential for diverse industrial applications. However, alginate lacks properties such as stability under aqueous conditions and it is difficult to control the rate of degradation of alginate-based materials, crucial for various medical applications. Therefore, researchers have modified alginate using physical or chemical approaches to enhance physical properties, biocompatibility, solubility and also to control the biodegradability of alginate-based materials. Crosslinking using ionic, covalent, photo and enzymatic approaches are one of the preferred methods for modifying the properties of alginates and its derivatives. Crosslinking binds the individual polymer chains with one another to form a network that enhances mechanical properties and stability. Among the different crosslinking approaches, ionic crosslinking provides biomaterials with limited stability whereas biomaterials with high mechanical stability can be prepared by covalent crosslinking. Although a wide variety of crosslinking chemicals and approaches are available to make alginate suitable for various applications, the methods used, properties and applications of the cross-linked materials vary significantly between studies. There are very few reports that have compared and evaluated the benefits of using different crosslinking approaches and the properties and applications of cross-linked alginate. In this review, the various methods of crosslinking alginates, their advantages, and limitations have been reviewed with particular emphasis on medical applications of alginate. The data for writing the review was obtained using search engines like Google scholar, Sci-hub and Sci finder and the keywords used include alginate, crosslinking, ionic, covalent, photo, enzymatic, biomedical applications.

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“…The first paper in this area addresses the problem of developing biocompatible positive photoresists for photochemical patterning to manipulate cell cultures through cell growth on the surface or entrapment within the hydrogel [11]. The next paper continues the soft materials theme, providing a review of temperature responsive thermophilic hydrogels with tunable stimuli-responsive properties [12].…”

Section: Materials Process Engineeringmentioning

confidence: 99%

Special Issue “Feature Papers”

Henson

2015

Processes

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Photochemical Patterning of Ionically Cross-Linked Hydrogels

Cited by 23 publications

References 64 publications

Design of Porous Alginate Hydrogels by Sacrificial CaCO₃ Templates: Pore Formation Mechanism

Design of Porous Alginate Hydrogels by Sacrificial CaCO₃ Templates: Pore Formation Mechanism

Chemical Modifications of Alginate and Its Derivatives

Special Issue “Feature Papers”

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Photochemical Patterning of Ionically Cross-Linked Hydrogels

Cited by 23 publications

References 64 publications

Design of Porous Alginate Hydrogels by Sacrificial CaCO3 Templates: Pore Formation Mechanism

Design of Porous Alginate Hydrogels by Sacrificial CaCO3 Templates: Pore Formation Mechanism

Chemical Modifications of Alginate and Its Derivatives

Special Issue “Feature Papers”

Contact Info

Product

Resources

About

Design of Porous Alginate Hydrogels by Sacrificial CaCO₃ Templates: Pore Formation Mechanism

Design of Porous Alginate Hydrogels by Sacrificial CaCO₃ Templates: Pore Formation Mechanism