Mechanical properties of silica hydrogels prepared and aged at physiological conditions: testing in the compression mode

Krupa, Igor; Nedelčev, Tomáš; Račko, Dušan; Lacı́k, Igor

doi:10.1007/s10971-009-2064-5

Cited by 36 publications

(15 citation statements)

References 14 publications

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“…A pre-compressive load of 10 mN was applied to the samples. The stress-strain curve being nonlinear, the behavior of the hydrogels was described but the phenomenological relationship used for different applications [27,28]:…”

mentioning

confidence: 99%

Nanofibrillated cellulose composite hydrogel for the replacement of the nucleus pulposus

Borges¹,

Eyholzer²,

Duc³

et al. 2011

Acta Biomaterialia

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a b s t r a c tThe swelling and compressive mechanical behavior as well as the morphology and biocompatibility of composite hydrogels based on Tween Ò 20 trimethacrylate (T3), N-vinyl-2-pyrrolidone (NVP) and nanofibrillated cellulose (NFC) were assessed in the present study. The chemical structure of T3 was verified by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance, and the degree of substitution was found to be around 3. Swelling ratios of neat hydrogels composed of different concentrations of T3 and NVP were found to range from 1.5 to 5.7 with decreasing concentration of T3. Various concentrations of cellulose nanofibrils (0.2-1.6 wt.%) were then used to produce composite hydrogels that showed lower swelling ratios than neat ones for a given T3 concentration. Neat and composite hydrogels exhibited a typical nonlinear response under compression. All composite hydrogels showed an increase in elastic modulus compared to neat hydrogel of about 3-to 8-fold, reaching 18 kPa at 0% strain and 62 kPa at 20% strain for the hydrogel with the highest NFC content. All hydrogels presented a porous and homogeneous structure, with interconnected pore cells of around 100 nm in diameter. The hydrogels are biocompatible. The results of this study demonstrate that composite hydrogels reinforced with NFC may be viable as nucleus pulposus implants due to their adequate swelling ratio, which may restore the annulus fibrosus loading, and their increased mechanical properties, which could possibly restore the height of the intervertebral discs.

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mentioning

confidence: 99%

Nanofibrillated cellulose composite hydrogel for the replacement of the nucleus pulposus

Borges¹,

Eyholzer²,

Duc³

et al. 2011

Acta Biomaterialia

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“…The encapsulation gel developed here provided a significant improvement over those developed previously: Krupa et al () reported silica gels aged under physiological conditions with a maximum σ f = 112 kPa and E = 0.336 MPa, respectively. Perullini et al () reported a lower E of 0.065 kPa and did not report σ f .…”

Section: Resultsmentioning

confidence: 77%

“…Therefore, the silica gel composition with v ¼ 0.34 that provided the best combination of biodegradation activity (285 AE 42 nmol/L-s) and mechanical strength (s f ¼ 652 AE 88 kPa and E ¼ 15.8 AE 2.0 MPa), was chosen for the longevity and permeability studies. The encapsulation gel developed here provided a significant improvement over those developed previously: Krupa et al (2009) reported silica gels aged under physiological conditions with a maximum s f ¼ 112 kPa and E ¼ 0.336 MPa, respectively. Perullini et al (2011) reported a lower E of 0.065 kPa and did not report s f .…”

Section: Effect Of Alcohol On Biodegradationmentioning

confidence: 78%

Engineering of a silica encapsulation platform for hydrocarbon degradation using Pseudomonas sp. NCIB 9816‐4

Sakkos

Kieffer

Mutlu

et al. 2015

Biotech & Bioengineering

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Industrial application of encapsulated bacteria for biodegradation of hydrocarbons in water requires mechanically stable materials. A silica gel encapsulation method was optimized for Pseudomonas sp. NCIB 9816-4, a bacterium that degrades more than 100 aromatic hydrocarbons. The design process focused on three aspects: (i) mechanical property enhancement; (ii) gel cytocompatibility; and (iii) reduction of the diffusion barrier in the gel. Mechanical testing indicated that the compressive strength at failure (σf ) and elastic modulus (E) changed linearly with the amount of silicon alkoxide used in the gel composition. Measurement of naphthalene biodegradation by encapsulated cells indicated that the gel maintained cytocompatibility at lower levels of alkoxide. However, significant loss in activity was observed due to methanol formation during hydrolysis at high alkoxide concentrations, as measured by FTIR spectroscopy. The silica gel with the highest amount of alkoxide (without toxicity from methanol) had a biodegradation rate of 285 ± 42 nmol/L-s, σf = 652 ± 88 kPa, and E = 15.8 ± 2.0 MPa. Biodegradation was sustained for 1 month before it dropped below 20% of the initial rate. In order to improve the diffusion through the gel, polyvinyl alcohol (PVA) was used as a porogen and resulted in a 48 ± 19% enhancement in biodegradation, but it impacted the mechanical properties negatively. This is the first report studying how the silica composition affects biodegradation of naphthalene by Pseudomonas sp. NCIB 9816-4 and establishes a foundation for future studies of aromatic hydrocarbon biodegradation for industrial application.

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“…The degradation byproduct, Si(OH) 4 , of the hydrogels was measured using an established colorimetric assay as described elsewhere. 52 Briefly, ammonium molybdate (10%) was added to each aliquot to form silic-monobdenic acid. Then, concentrated hydrogen chloride (36%) was added.…”

Section: In Vitro Degradationmentioning

confidence: 99%

Multi‐arm PEG/Silica Hydrogel for Sustained Ocular Drug Delivery

Lü

Zahedi

Forman

et al. 2014

Journal of Pharmaceutical Sciences

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Mechanical properties of silica hydrogels prepared and aged at physiological conditions: testing in the compression mode

Cited by 36 publications

References 14 publications

Nanofibrillated cellulose composite hydrogel for the replacement of the nucleus pulposus

Nanofibrillated cellulose composite hydrogel for the replacement of the nucleus pulposus

Engineering of a silica encapsulation platform for hydrocarbon degradation using Pseudomonas sp. NCIB 9816‐4

Multi‐arm PEG/Silica Hydrogel for Sustained Ocular Drug Delivery

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