A flexible bioelectrode based on IrO2–coated metallized polypropylene micromembrane

Chou, Shih‐Chien; Sun, Bo; Cheang, Wai Hong; Tso, Kuang Chih; Fan, Tzu Ling; Chiao, J.-C.; Wu, Pu Wei

doi:10.1016/j.ceramint.2021.08.150

Cited by 13 publications

(6 citation statements)

References 51 publications

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“…In our pH-sensing results, the PPMM@PDA/PVA(1/8)@Au@IrO 2 exhibited a super-Nernstian response with a pH-sensing slope of − 74.45 mV/pH. This value was slightly smaller than the theoretical value of − 88.7 mV/pH because according to our earlier XPS analysis, our sample was consisted of both hydrated and anhydrous IrO 2 32 . It is known that the anhydrous IrO 2 reveals an inferior sensing response to that of hydrated IrO 2 27 .…”

Section: Resultsmentioning

confidence: 62%

A flexible IrO2 membrane for pH sensing

Chou

Hsieh

Cheang

et al. 2022

Sci Rep

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An optimized mixture of polydopamine (PDA) and polyvinyl alcohol (PVA) is employed as the surface functionalizing agent and reducing agent to encapsulate individual polypropylene (PP) fibers of polypropylene micromembrane (PPMM). The functionalized PPMM becomes hydrophilic to allow the formation of Au nuclei for subsequent electroless Au deposition. The metalized PPMM is further deposited with IrO2 nanoparticles, and evaluated as a flexible and porous pH sensor. Images from scanning electron microscope confirms the uniform formation of IrO2 nanoparticles on Au-coated PP fibers. For pH-sensing performance, the IrO2-decorated metalized PPMM reveals a super-Nernstian response for a sensing slope of -74.45 mV/pH in aqueous solutions with pH value ranging between 2 and 12. In addition, the pH-sensing performance is properly maintained after 5000 bending cycles and hysteresis is modest in an acidic environment. The cell viability test indicates a negligible bio-toxicity. Our strategy of using a conductive polymeric membrane decorated with IrO2 nanoparticles enables possible sensing applications in wearable and implantable electronics.

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Section: Resultsmentioning

confidence: 62%

A flexible IrO2 membrane for pH sensing

Chou

Hsieh

Cheang

et al. 2022

Sci Rep

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“…5 show sensitivities of −65 mV/pH for the acid to alkaline (2-4-7-10-13) steps, and −64.8 mV/pH for alkaline to acid (13-10-7-4-2) steps. Symmetrical cathodic and anodic peaks in the CV analysis [45] indicated similar potentials generated at particular pH levels, which resulted in similar sensitivities for both sequences. The multiple oxidation states of Ir 3+ , Ir 4+ , and Ir 5+ during CV analysis [45] agreed well with the super-Nernstian response of the PWE electrode.…”

Section: Ph Response Of Pwe In Wide Ph Range Of Ph 2 To 13mentioning

confidence: 88%

“…The IrO 2 nanoparticles were electrodeposited on the metalized film PPMM@Au for the pH sensing function using IrO 2 suspension reported [45]. The solution of 0.005-M potassium hexachloroiridate (K 2 IrCl 6 ) was first adjusted to pH 12 by adding NaOH and then heated at 90 • C for 20 min to form a colloidal suspension.…”

Section: A Electrode Fabricationmentioning

confidence: 99%

“…Our group has previously demonstrated the performance of the sensing film with the IrO 2 nanoparticles coated on the metalized PPMM [37], [40], [45], [46] against a bulky commercial reference electrode. In this work, the pH-sensitive film electrode is further integrated with a planar Ag/AgCl film as the reference electrode.…”

Section: Introductionmentioning

confidence: 99%

“…The fabrication of the sensing film is briefly described here. The PPMM was gold (Au) metalized by an electroless process [40], [45], and IrO 2 nanoparticles were further deposited by an electrochemical process using IrO 2 colloid suspension [47]. Electroless metallization of gold on individual PPMM fibers used polydopamine (PDA) and poly vinyl alcohol (PVA) as the adhesive, wetting, and reducing agents to improve their hydrophilicity of PPMM fibers.…”

Section: Introductionmentioning

confidence: 99%

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Porous Polypropylene Membrane Based pH Sensing for Skin Monitoring

et al. 2022

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An iridium oxide-based electrical pH sensor that is suitable to be embedded in an electronic bandage for skin monitoring has been developed. The electrical pH sensor does not entail high-temperature fabrication processes thus is suitable to be built on polypropylene micro membrane (PPMM), a paperlike substrate, which is inert, gas-permeable, and biomechanically-compatible to tissue. The PPMM was metalized by an electroless gold-coating process and iridium oxide nanoparticles were electrodeposited on the porous membranes. The reference electrode was made by screen printing Ag/AgCl paste on the substrate. pH responses of the IrO 2 PPMM against a commercial reference electrode or the planar Ag/AgCl reference electrode were examined. A super-Nernstian sensitivity of −66.8 mV/pH was achieved with the PPMMbased sensor in a pH range from pH 2 to 13. The electrodes also produced similar responses in smaller pH ranges of pH 5 to 8 and around pH 7. Output potential characterization, such as cyclic voltammetry, hysteresis, response time, potential drift, deviation, fluctuation, and potential stability, showed repeatable and stable pH responses in physiologically relevant pH ranges. Interference factors such as salt concentration, viscosity and temperature have also been investigated. The results show that the calibration procedures should consider these factors specific to targeted applications. The planar pH-sensitive electrodes show reliable performance in a bandage configuration designed and packaged for wound monitoring. The accuracy assessment in a Clarke error grid and the result of sensing pH induced by uric acid showed the feasibility of bandage applications. The electrical and biocompatible electrodes embedded in breathable porous bandages can be integrated with portable electronics to be used as wearables for wireless tissue monitoring.INDEX TERMS pH sensor, planar, iridium oxide, polypropylene micro membrane, electronic bandage.

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