Tailoring Properties of Biocompatible PEG-DMA Hydrogels with UV Light

Bäckström, Sania; Benavente, J.; Berg, Rolf W.; Stibius, Karin B.; Larsen, Marianne Spanget; Bohr, Henrik; Hélix-Nielsen, Claus

doi:10.4236/msa.2012.36060

Cited by 37 publications

(50 citation statements)

References 29 publications

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“…The prepared hydrogels exhibited absorption bands characteristic of DMA, along with bands characteristic of PEG, prior to exposure to water and the addition of cross-linking agents. On cross-linking, the DMA C=C bands were extinguished and the C=O band was shifted to greater wavenumbers, and the PEG bands were unaltered as observed in similar hydrogel materials 27–30 . Subsequent hydration of the cross-linked gel to reach equilibrium swelling in water, followed by dehydration, and then rehydration, did not alter the absorption bands associated with either PEG or DMA.…”

Section: Materials and Methods†mentioning

confidence: 65%

Mechanical measurements of heterogeneity and length scale effects in PEG-based hydrogels

et al. 2015

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Colloidal-probe spherical indentation load-relaxation experiments with a probe radius of 3 μm are conducted on poly(ethylene glycol) (PEG) hydrogel materials to quantify their steady-state mechanical properties and time-dependent transport properties via a single experiment. PEG-based hydrogels are shown to be heterogeneous in both morphology and mechanical stiffness at this scale; a linear-harmonic interpolation of hyperelastic Mooney-Rivlin and Boussinesq flat-punch indentation models was used to describe the steady-state response of the hydrogels and determine upper and lower bounds for indentation moduli. Analysis of the transient load-relaxation response during displacement-controlled hold periods provides a means of extracting two time constants τ1 and τ2, where τ1 and τ2 are assigned to the viscoelastic and poroelastic properties, respectively. Large τ2 values at small indentation depths provide evidence of a non-equilibrium state characterized by a phenomenon that restricts poroelastic fluid flow through the material; for larger indentations, the variability in τ2 values decreases and pore sizes estimated from τ2 via indentation approach those measured via macroscopic swelling experiments. The contact probe methodology developed here provides a means of assessing hydrogel heterogeneity, including time-dependent mechanical and transport properties, and has potential implications in hydrogel biomedical and engineering applications.

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Section: Materials and Methods†mentioning

confidence: 65%

Mechanical measurements of heterogeneity and length scale effects in PEG-based hydrogels

et al. 2015

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“…The presence of the coating itself may push viable neurons away from the recording site of the probe as PEG hydrogels aren’t naturally conductive 50 . This obstacle may be potentially overcome through incorporation of conducting polymers into the coating itself 51,73 .…”

Section: Discussionmentioning

confidence: 99%

Characterization of Mechanically Matched Hydrogel Coatings to Improve the Biocompatibility of Neural Implants

Spencer

Ramadi

et al. 2017

Sci Rep

158

153

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Glial scar is a significant barrier to neural implant function. Micromotion between the implant and tissue is suspected to be a key driver of glial scar formation around neural implants. This study explores the ability of soft hydrogel coatings to modulate glial scar formation by reducing local strain. PEG hydrogels with controllable thickness and elastic moduli were formed on the surface of neural probes. These coatings significantly reduced the local strain resulting from micromotion around the implants. Coated implants were found to significantly reduce scarring in vivo, compared to hard implants of identical diameter. Increasing implant diameter was found to significantly increase scarring for glass implants, as well as increase local BBB permeability, increase macrophage activation, and decrease the local neural density. These results highlight the tradeoff in mechanical benefit with the size effects from increasing the overall diameter following the addition of a hydrogel coating. This study emphasizes the importance of both mechanical and geometric factors of neural implants on chronic timescales.

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“…Natural materials are typically cross-linked via chain entanglement, but can be chemically modified to promote crosslinking. Synthetic polymers are chemically synthesized and are usually cross-linked via chemical methods (Figure 2 39-41 ), including photo- and thermally-initiated polymerization. In comparison to natural hydrogels, synthetic hydrogels allow for improved control over physical properties, such as cross-linking density, mechanical strength, and enhanced tailoring of chemical and biological responses.…”

Section: Hydrogelsmentioning

confidence: 99%

Hydrogels that allow and facilitate bone repair, remodeling, and regeneration

et al. 2015

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Bone defects can originate from a variety of causes, including trauma, cancer, congenital deformity, and surgical reconstruction. Success of the current “gold standard” treatment (i.e., autologous bone grafts) is greatly influenced by insufficient or inappropriate bone stock. There is thus a critical need for the development of new, engineered materials for bone repair. This review describes the use of natural and synthetic hydrogels as scaffolds for bone tissue engineering. We discuss many of the advantages that hydrogels offer as bone repair materials, including their potential for osteoconductivity, biodegradability, controlled growth factor release, and cell encapsulation. We also discuss the use of hydrogels in composite devices with metals, ceramics, or polymers. These composites are useful because of the low mechanical moduli of hydrogels. Finally, the potential for thermosetting and photo-cross-linked hydrogels as three-dimensionally (3D) printed, patient-specific devices is highlighted. Three-dimensional printing enables controlled spatial distribution of scaffold materials, cells, and growth factors. Hydrogels, especially natural hydrogels present in bone matrix, have great potential to augment existing bone tissue engineering devices for the treatment of critical size bone defects.

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Tailoring Properties of Biocompatible PEG-DMA Hydrogels with UV Light

Cited by 37 publications

References 29 publications

Mechanical measurements of heterogeneity and length scale effects in PEG-based hydrogels

Mechanical measurements of heterogeneity and length scale effects in PEG-based hydrogels

Characterization of Mechanically Matched Hydrogel Coatings to Improve the Biocompatibility of Neural Implants

Hydrogels that allow and facilitate bone repair, remodeling, and regeneration

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