Fabrication of biocompatible and conductive polypropylene micromembrane as a soft and porous electrode

Chou, Shih‐Chien; Sun, Bo; Fan, Tzu Ling; Chiang, Yung Tai; Chiao, J.-C.; Wu, Pu Wei

doi:10.1016/j.jtice.2021.09.016

Cited by 8 publications

(5 citation statements)

References 32 publications

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“…The pH values of the Tris buffer and Au plating solutions were 8.5 and 6.5, respectively. Previously, the mechanical strength and flexibility of PPMM@Au were demonstrated by bending the sample at 60 • C for 10,000 bending cycles [40]. Thus, the connectivity for electrical signals should be secured after the mechanical bending of the film in wearables.…”

Section: A Electrode Fabricationmentioning

confidence: 99%

“…To distinguish the common use of polypropylene (PP) films that can be any thickness or pore size, the thin film used in our fabrication is called polypropylene micro membrane (PPMM). The porometer analysis showed the PPMM has an average flow pore diameter of 0.247 µm and a pore flow pressure of 17.562 psi [40]. The porous gas-permeable PPMM is also known to be inert, foul resistant and biocompatible with robust mechanical strength and chemical resistance [41], [42], [43], [44].…”

Section: Introductionmentioning

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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Section: A Electrode Fabricationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Porous Polypropylene Membrane Based pH Sensing for Skin Monitoring

et al. 2022

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“…Selective laser sintering and photonic curing help to achieve higher conductivities at low temperatures but operate on a high amount of power [30][31][32][33]. New deposition methods with wet plating at room temperature overcome such limitations [34][35][36]. Iridium oxide (IrO x ) was synthesized as an H + -ion selective membrane for targeted applications [37].…”

Section: Introductionmentioning

confidence: 99%

Printable and Flexible Iridium Oxide-Based pH Sensor by a Roll-to-Roll Process

2023

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A flexible pH sensor based on using iridium oxide (IrOx) as the sensing film was developed by the roll-to-roll (R2R) process. The inert and biocompatible properties of IrOx make it a desired metal oxide for pH-sensing applications. The flexible substrates being continuously processed by the R2R technique provides the advantages of scalability, reconfigurability, resiliency, on-demand manufacturing, and high throughput, without the need for vacuum systems. Potential sweeps by cyclic voltammetry across the IrOx film against commercial and planar Ag/AgCl electrodes validated the reversible electrochemical mechanisms. Multiple IrOx electrodes showed similar output potentials when continuously tested in the pH range of 2–13, indicating good fabrication uniformity. For practical applications, planar IrOx/Ag-AgCl pairs developed on polyimide substrates were tested, with a good linear fit within pH 2–13, achieving Nernstian responses of around −60.6 mV/pH. The pH sensors showed good repeatability when analyzed with hysteresis, drift, fluctuation, and deviation as the stability factors. The selectivity of the interference ions and the effect of temperature were studied and compared with the reported values. The electrodes were further laminated in a process compatible with the R2R technique for packaging. The flexible sensors were tested under flat and curved surface conditions. Tests in artificial sweat and viscous solutions were analyzed in the Clarke error grid, showing reliable pH-sensing performance. The materials used during the manufacturing processes were sustainable, as the active materials were in small amounts and there was no waste during processing. No toxic chemicals were needed in the fabrication processes. The cost-effective and efficient materials and the fabrication process allow for rapid production that is necessary for disposable and point-of-care devices. Flexible electronics provide a platform for device and sensor integration and packaging, which enables Internet-of-things (IoT) network applications.

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