Glass Wool–H2O2/CoCl2 test system for in vitro evaluation of biodegradative stress cracking in polyurethane elastomers

Zhao, Qinghong; Casas-Bejar, Jesus; Urbanski, Peter; Stokes, Ken

doi:10.1002/jbm.820290406

Cited by 65 publications

(85 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Immune cells attack implants in vivo by releasing ROS that are not present in a saline solution. Previous work has simulated in vivo degradation in the presence of these chemicals by including hydrogen peroxide (Meijs et al 1993, Yokoyama et al 2007, Patrick et al 2011 or generating reactive species in situ via the reaction of hydrogen peroxide with the metal ions in aging protocols (Ali et al 1993, Zhao et al 1995. One of the challenges of including ROS is their short lifetimes.…”

Section: Reactive Accelerated Aging Systemmentioning

confidence: 99%

“…However, this approach alone may not adequately capture the aggressive chemical environment that is created by activated immune cells, which release digestive enzymes and reactive oxygen species (ROS) (Badwey and Karnovsky 1980, Halliwell 1992, Polikov et al 2005, Freinbichler et al 2011, Patrick et al 2011. In our system, we have included hydrogen peroxide to mimic the effect of ROS generation during the brain's injury response (Ali et al 1993, Zhao et al 1995, Patrick et al 2011.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

et al. 2015

View full text Add to dashboard Cite

Objective-A challenge for implementing high bandwidth cortical brain-machine interface devices in patients is the limited functional lifespan of implanted recording electrodes. Development of implant technology currently requires extensive non-clinical testing to demonstrate device performance. However, testing the durability of the implants in vivo is timeconsuming and expensive. Validated in vitro methodologies may reduce the need for extensive testing in animal models.Approach-Here we describe an in vitro platform for rapid evaluation of implant stability. We designed a reactive accelerated aging (RAA) protocol that employs elevated temperature and reactive oxygen species (ROS) to create a harsh aging environment. Commercially available microelectrode arrays (MEAs) were placed in a solution of hydrogen peroxide at 87 °C for a period of 7 days. We monitored changes to the implants with scanning electron microscopy and broad spectrum electrochemical impedance spectroscopy (1 Hz-1 MHz) and correlated the physical changes with impedance data to identify markers associated with implant failure.Main results-RAA produced a diverse range of effects on the structural integrity and electrochemical properties of electrodes. Temperature and ROS appeared to have different effects on structural elements, with increased temperature causing insulation loss from the electrode microwires, and ROS concentration correlating with tungsten metal dissolution. All array types experienced impedance declines, consistent with published literature showing chronic (>30 days) declines in array impedance in vivo. Impedance change was greatest at frequencies <10 Hz, and smallest at frequencies 1 kHz and above. Though electrode performance is traditionally characterized by impedance at 1 kHz, our results indicate that an impedance change at 1 kHz is not a reliable predictive marker of implant degradation or failure.Significance-ROS, which are known to be present in vivo, can create structural damage and change electrical properties of MEAs. Broad-spectrum electrical impedance spectroscopy

show abstract

Section: Reactive Accelerated Aging Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

et al. 2015

View full text Add to dashboard Cite

show abstract

“…In compliance with the literature, 21,22 hydrogen peroxide was selected as the oxidizing agent while simultaneous oxidative and acidic conditions were reproduced using an HNO 3 solution, the only acidic medium described in the literature as being able to discriminate between various polyurethanes. 31 The samples were immersed in a solution containing either 20% (w/v) H 2 O 2 or 0.5N HNO 3 during periods ranging from 0 to 21 days, due to the rather aggressive nature of these solutions.…”

Section: Aging Of the Specimensmentioning

confidence: 99%

“…18 Several attempts have been made to reproduce chemical oxidation in vitro [19][20][21] but with contradictory or limited results unless under strong or sophisticated operating conditions. 22 Moreover, the enzymatic and oxidative degradation in vitro has not yet led to clear and unequivocal results as the dynamic in vivo conditions are difficult to reproduce in static in vitro experiments. [23][24][25][26][27][28][29][30] Within the polyurethane family of polymers, polyether urethanes and polycarbonate urethanes both have been shown to present better in vitro and in vivo chemical stability compared to polyesterurethanes.…”

Section: Introductionmentioning

confidence: 99%

Chemical stability of polyether urethanes versus polycarbonate urethanes

Tanzi

Mantovani

Petrini

et al. 1997

J. Biomed. Mater. Res.

148

121

View full text Add to dashboard Cite

The relative chemical stability of two commercially available polyurethanes-Pellethane, currently used in biomedical devices, and Corethane, considered as a potential biomaterial-was investigated following aging protocols in hydrolytic and oxidative conditions (HOC, water, hydrogen peroxide, and nitric acid) and in physiological media (PHM, phosphate buffer, lipid dispersion, and bile from human donors). The chemical modifications induced on these polymers were characterized using differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and Fourier transform infrared spectroscopy (FTIR). With the exception of nitric acid, all of the aging media promoted a mild hydrolytic reaction leading to a slight molecular weight loss in both polymers. When aged in water and hydrogen peroxide, Pellethane experienced structural modifications through microdomain phase separation along with an increase of the order within the soft-hard segment domains. The incubation of Pellethane in nitric acid also resulted in an important decrease of the melting temperature of its hard segments with chain scission mechanisms. Moreover, incubation in PHM led to an increase of the order within shorter hard-segment domains. FTIR data revealed the presence of aliphatic amide molecules used as additives on the Pellethane's surface. The incubation of Corethane under the same conditions promoted an almost uniform molecular reorganization through a phase separation between the hard and soft segments as well as an increase of the short-range order within the hard-segment domains. Incubation of this polymer in nitric acid also resulted in a chain scission process that was less pronounced than that measured for the Pellethane samples. Finally, lipid adsorption occurred on the Corethane sample incubated in bile for 120 days. Overall data indicate that polycarbonate urethane presents a greater chemical stability than does polyetherurethane.

show abstract

“…Many years of use and testing of the Pellethane 2636 series of PTMO-based polyurethanes has shown that P80A is far more susceptible to environmental stress cracking (ESC) in vivo, and its biostability performance more process-sensitive than its harder counterpart, P55D. [17][18][19][20]35 Figure 1 shows scanning electron micrographs of explanted P80A and P55D polymers after a strained (150% strain) 3-month subcutaneous implantation in sheep in our laboratories. The P80A shows evidence of deep surface cracks where as P55D shows no visible signs of degradation.…”

Section: Introductionmentioning

confidence: 99%

The influence of composition ratio on the morphology of biomedical polyurethanes

Martin

Meijs

Gunatillake

et al. 1999

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

Two series of thermoplastic polyurethane elastomers were synthesized from 4,4Ј-methylenediphenyl diisocyanate (MDI), 1,4-butanediol (BDO) chain extender, and each of poly(tetramethylene oxide) (PTMO) and poly(hexamethylene oxide) (PHMO) macrodiols. The PTMO and PHMO molecular weights were kept constant at 993 and 852 g/mol, respectively. In the PTMO-based series, the composition ratio was varied between 48 and 58% (w/w) of macrodiol; 2 commercially available PTMO-based polymers were also included. These were Pellethane 2363 80A and its harder counterpart, Pellethane 2363 55D. In the PHMO-based series, the composition ratio was varied between 50 and 60% (w/w) of macrodiol. The materials were characterized by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS). Mechanical performance was also assessed by tensile testing, stress hysteresis, and hardness testing. Altering the composition ratio had a similar effect on morphology and properties for both the PTMO and PHMO-based series. An increase in hard segment content was associated with increased hard microdomain crystallinity, hardness, and stiffness. In both series, he beginning of hard microdomain interconnectivity was observed at a composition ratio of 52% soft segment. That is to say, for the processing and annealing conditions employed, macrodiol contents of 52% and below began to produce continuous, rather than discrete, hard microdomains. Pellethane 80A was shown to have a discrete hard microdomain morphology, while Pellethane 55D was shown to incorporate interconnecting hard microdomains. It is suggested that the superior biostability performance of Pellethane 55D relative to Pellethane 80A may be related to its interconnecting hard microdomain texture. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 937-952, 1999

show abstract

Glass Wool–H₂O₂/CoCl₂ test system for in vitro evaluation of biodegradative stress cracking in polyurethane elastomers

Cited by 65 publications

References 15 publications

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

Chemical stability of polyether urethanes versus polycarbonate urethanes

The influence of composition ratio on the morphology of biomedical polyurethanes

Contact Info

Product

Resources

About