Enhanced wear resistance of orthopaedic bearing due to the cross-linking of poly(MPC) graft chains induced by gamma-ray irradiation

Conducting polymer (CP)-based hydrogels exhibit the behaviors of bending or contraction/relaxation due to electrical stimulation. They are similar in some ways to biological organs and have advantages regarding manipulation and miniaturization. Thus, these hydrogels have attracted considerable interest for biomedical applications. In this study, we prepared PPy/PVP hydrogel with different concentrations and content through polymerization and cross-linking induced by gamma-ray irradiation at 25 kGy to optimize the mechanical properties of the resulting PPy/PVP hydrogel. Optimization of the PPy/PVP hydrogel was confirmed by characterization using scanning electron microscopy, gel fraction, swelling ratio, and Fourier transform infrared spectroscopy. In addition, we assessed live-cell viability using live/dead assay and CCK-8 assay, and found good cell viability regardless of the concentration and content of Py/pTS. The conductivity of PPy/PVP hydrogel was at least 13 mS/cm. The mechanical properties of PPy/PVP hydrogel are important factors in their application for biomaterials. It was found that 0.15PPy/PVP20 (51.96 ± 6.12 kPa) exhibited better compressive strength than the other samples for use in CP-based hydrogels. Therefore, it was concluded that gamma rays can be used to optimize PPy/PVP hydrogel and that biomedical applications of CP-based hydrogels will be possible.

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Structure dependence of gamma ray irradiation effects on polyurethane and epoxy resin studied by PAL technique

Iraqi Journal of Physics (IJP) ◽

10.30723/ijp.v13i27.274 ◽

2019 ◽

Vol 13 (27) ◽

pp. 157-163

Author(s):

Hayder S. Hussain

Keyword(s):

Free Volume ◽

Gamma Ray ◽

Cross Linking ◽

Hole Size ◽

Irradiation Effects ◽

Fractional Free Volume ◽

Structure Dependence ◽

Positron Annihilation Lifetime ◽

Gamma Ray Irradiation ◽

Free Volume Hole

Positron annihilation lifetime (PAL) technique has been employed tostudy the microstructural changes of polyurethane (PU), EUXIT 101and epoxy risen (EP), EUXIT 60 by Gamma-ray irradiation with thedose range (95.76 - 957.6) kGy. The size of the free volume hole andtheir fraction in PU and EP were determined from ortho-positroniumlifetime component and its intensity in the measured lifetime spectra.The results show that the irradiation causes significant changes in thefree volume hole size (Vh) and the fractional free volume (Fh), andthereby the microstructure of PU and EP. The results indicate thatthe γ-dose increases the crystallinity in the amorphous regions of PUand increase the cross-linking of EP.

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Hydroxy-Tyrosol as a Free Radical Scavenging Molecule in Polymeric Hydrogels Subjected to Gamma-Ray Irradiation

Processes ◽

10.3390/pr9030433 ◽

2021 ◽

Vol 9 (3) ◽

pp. 433

Author(s):

Mauro Fiorini ◽

Veronica Crognaletti ◽

Omar Sabry ◽

Lorenzo Scalise ◽

Paolo Fattori

Keyword(s):

Free Radical ◽

Gamma Ray ◽

Radical Scavenging ◽

Free Radical Scavenging ◽

Free Radical Scavenger ◽

Cross Linking ◽

Radical Scavenger ◽

Gamma Ray Irradiation ◽

Anti Oxidant ◽

Polymeric Hydrogels

Biomedical engineering is employing hydrogels with increasingly exciting possibilities for the treatment and regeneration of pathologically altered, degenerated, or traumatized tissues. Still, the sterilization processes may undesirably change the chemical and physical properties of hydrogels through cross-linking reactions. This work aims to characterize a new method of producing polyethylene oxide (PEO) hydrogels exploiting hydroxy-tyrosol (HT), an anti-oxidant molecule derived from olive leaf and olive oil, as a free radical scavenger to either prevent or limit gamma-ray-induced cross-linking. For this purpose, we produced hydrogels with PEO with two different buffer solutions (phosphate and citrate), varying HT concentration. We analyzed hydrogel preparations before and after gamma-ray irradiation, assessing the viscosity through rheological analysis and the chemical changes through IR analysis. We performed high-performance liquid chromatography (HPLC) analysis to measure residual HT in hydrogels after irradiation. The obtained results show that radiation-induced cross-linking and increase in viscosity of PEO hydrogels can be prevented by tailoring the concentration of HT as a free radical scavenging agent. Irradiation only consumes small amounts of HT; its presence in polymeric hydrogels can significantly impact biomedical applications by its anti-oxidant and anti-microbial activities.

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