Towards the translation of electroconductive organic materials for regeneration of neural tissues

Manousiouthakis, Eleana; Park, Junggeon; Hardy, John G.; Lee, Jae Young; Schmidt, Christine E.

doi:10.1016/j.actbio.2021.07.065

Cited by 42 publications

(41 citation statements)

References 304 publications

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“…Caveats are, as mentioned above, that our number of animals was small and the differences were also small, so further research is needed. We have also not explored the electroconductive properties of Mg metal, which could influence nerve regeneration, except to note that Mg is significantly more conductive than Ti (unpublished observations), which was our control for metal effects in general [ 52 ].…”

Section: Discussionmentioning

confidence: 99%

Effects of Altering Magnesium Metal Surfaces on Degradation In Vitro and In Vivo during Peripheral Nerve Regeneration

et al. 2023

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In vivo use of biodegradable magnesium (Mg) metal can be plagued by too rapid a degradation rate that removes metal support before physiological function is repaired. To advance the use of Mg biomedical implants, the degradation rate may need to be adjusted. We previously demonstrated that pure Mg filaments used in a nerve repair scaffold were compatible with regenerating peripheral nerve tissues, reduced inflammation, and improved axonal numbers across a short—but not long—gap in sciatic nerves in rats. To determine if the repair of longer gaps would be improved by a slower Mg degradation rate, we tested, in vitro and in vivo, the effects of Mg filament polishing followed by anodization using plasma electrolytic oxidation (PEO) with non-toxic electrolytes. Polishing removed oxidation products from the surface of as-received (unpolished) filaments, exposed more Mg on the surface, produced a smoother surface, slowed in vitro Mg degradation over four weeks after immersion in a physiological solution, and improved attachment of cultured epithelial cells. In vivo, treated Mg filaments were used to repair longer (15 mm) injury gaps in adult rat sciatic nerves after placement inside hollow poly (caprolactone) nerve conduits. The addition of single Mg or control titanium filaments was compared to empty conduits (negative control) and isografts (nerves from donor rats, positive control). After six weeks in vivo, live animal imaging with micro computed tomography (micro-CT) showed that Mg metal degradation rates were slowed by polishing vs. as-received Mg, but not by anodization, which introduced greater variability. After 14 weeks in vivo, functional return was seen only with isograft controls. However, within Mg filament groups, the amount of axonal growth across the injury site was improved with slower Mg degradation rates. Thus, anodization slowed degradation in vitro but not in vivo, and degradation rates do affect nerve regeneration.

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Section: Discussionmentioning

confidence: 99%

Effects of Altering Magnesium Metal Surfaces on Degradation In Vitro and In Vivo during Peripheral Nerve Regeneration

et al. 2023

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“…SEM images (Figure S2) of the surfaces of non-conductive hydrogels are smooth on the µm scale by comparison with the conductive hydrogels due to the particles of lignin-doped PPy embedded within the conductive gels (the PPy particles were also observed to be distributed throughout the gel matrix as a sample spanning interpenetrating network of PPy in cross-sectional images). The conductance of dried gels was observed to be of the order of 2.65 × 10 −9 S/cm for the dried CS-PEG gels, and 8.88 × 10 −7 S/cm for the PPy containing gels, similar, albeit somewhat lower than analogous PPy-containing materials [74,101,102], which is likely due to the high content of PEG and lignin in these materials.…”

Section: Hydrogel Preparation and Characterizationmentioning

confidence: 90%

Electrochemically Enhanced Delivery of Pemetrexed from Electroactive Hydrogels

et al. 2022

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Electroactive hydrogels based on derivatives of polyethyleneglycol (PEG), chitosan and polypyrrole were prepared via a combination of photopolymerization and oxidative chemical polymerization, and optionally doped with anions (e.g., lignin, drugs, etc.). The products were analyzed with a variety of techniques, including: FT-IR, UV-Vis, 1H NMR (solution state), 13C NMR (solid state), XRD, TGA, SEM, swelling ratios and rheology. The conductive gels swell ca. 8 times less than the non-conductive gels due to the presence of the interpenetrating network (IPN) of polypyrrole and lignin. A rheological study showed that the non-conductive gels are soft (G′ 0.35 kPa, G″ 0.02 kPa) with properties analogous to brain tissue, whereas the conductive gels are significantly stronger (G′ 30 kPa, G″ 19 kPa) analogous to breast tissue due to the presence of the IPN of polypyrrole and lignin. The potential of these biomaterials to be used for biomedical applications was validated in vitro by cell culture studies (assessing adhesion and proliferation of fibroblasts) and drug delivery studies (electrochemically loading the FDA-approved chemotherapeutic pemetrexed and measuring passive and stimulated release); indeed, the application of electrical stimulus enhanced the release of PEM from gels by ca. 10–15% relative to the passive release control experiment for each application of electrical stimulation over a short period analogous to the duration of stimulation applied for electrochemotherapy. It is foreseeable that such materials could be integrated in electrochemotherapeutic medical devices, e.g., electrode arrays or plates currently used in the clinic.

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“…The time it takes for a polymer material to completely degrade and lose weight is also important. This time is referred to as the "disappearance time" (Chiong et al, 2021;Hosseini et al, 2021;Manousiouthakis et al, 2022). Depending on the chemical and physical properties and the rate of release, the degradation products can cause biocompatibility problems.…”

Section: Biodegradabilitymentioning

confidence: 99%

Biodegradable polymeric materials for flexible and degradable electronics

2022

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Biodegradable electronics have great potential to reduce the environmental footprint of electronic devices and to avoid secondary removal of implantable health monitors and therapeutic electronics. Benefiting from the intensive innovation on biodegradable nanomaterials, current transient electronics can realize full components’ degradability. However, design of materials with tissue-comparable flexibility, desired dielectric properties, suitable biocompatibility and programmable biodegradability will always be a challenge to explore the subtle trade-offs between these parameters. In this review, we firstly discuss the general chemical structure and degradation behavior of polymeric biodegradable materials that have been widely studied for various applications. Then, specific properties of different degradable polymer materials such as biocompatibility, biodegradability, and flexibility were compared and evaluated for real-life applications. Complex biodegradable electronics and related strategies with enhanced functionality aimed for different components including substrates, insulators, conductors and semiconductors in complex biodegradable electronics are further researched and discussed. Finally, typical applications of biodegradable electronics in sensing, therapeutic drug delivery, energy storage and integrated electronic systems are highlighted. This paper critically reviews the significant progress made in the field and highlights the future prospects.

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Towards the translation of electroconductive organic materials for regeneration of neural tissues

Cited by 42 publications

References 304 publications

Effects of Altering Magnesium Metal Surfaces on Degradation In Vitro and In Vivo during Peripheral Nerve Regeneration

Effects of Altering Magnesium Metal Surfaces on Degradation In Vitro and In Vivo during Peripheral Nerve Regeneration

Electrochemically Enhanced Delivery of Pemetrexed from Electroactive Hydrogels

Biodegradable polymeric materials for flexible and degradable electronics

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