Microfabricated and 3-D printed electroconductive hydrogels of PEDOT:PSS and their application in bioelectronics

• Published in: Biosensors & bioelectronics Vol. 168; p. 112568
• Main Authors: Aggas, John R., Abasi, Sara, Phipps, Jesse F., Podstawczyk, Daria A., Guiseppi-Elie, Anthony
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.11.2020
• Subjects: 3-D printing; biofabrication; bioprinting; Biosensing Techniques; biosensors; Bridged Bicyclo Compounds, Heterocyclic; capacitors; computer simulation; dielectric spectroscopy; Electrical impedance; electrochemistry; Electroconductive hydrogels; electrodes; Hydrogels; microarray technology; Microfabrication; nanomaterials; neural stem cells; Neuronal cells; Polymers; rheological properties; sulfonates; three-dimensional printing; 3-D printing; Neuronal cells; Electroconductive hydrogels; Microfabrication; Electrical impedance
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2020.112568

Biofabrication techniques such as microlithography and 3-D bioprinting have emerged in recent years as technologies capable of rendering complex, biocompatible constructs for biosensors, tissue and regenerative engineering and bioelectronics. While instruments and processes have been the subject of immense advancement, multifunctional bioinks have received less attention. A novel photocrosslinkable, hybrid bioactive and inherently conductive bioink formed from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) nanomaterials within poly(2-hydroxyethyl methacrylate-co-polyethyleneglycol methacrylate) p(HEMA-co-EGMA) was used to render complex hydrogel constructs through microlithographic fabrication and 3-D printing. Constructs were directly compared through established metrics of acuity and fidelity, using side-by-side comparison of microarray grids, triangles incorporating angles 15–90°, and a multi-ink hydrogel disk array. Compositional variation from 0.01 to 1.00 wt% PEDOT:PSS produced hydrogels of varying and tunable electrical and electrochemical properties, while maintaining similar rheological properties (up to 0.50 wt% PEDOT:PSS). Furthermore, hydrogel membrane resistances extracted from equivalent circuit modeling of electrical impedance spectroscopy data varied only according to the included wt% of PEDOT:PSS and were agnostic of fabrication method. An in-silico variable frequency active low-pass filter was developed using a microlithographically fabricated Individually Addressable Microband Electrode (IAME) as the filtering capacitor, wherein 3-D printed lines of varying wt% of PEDOT:PSS hydrogels were shown to alter the cutoff frequency of the analog filter, indicating a potential use as tunable 3-D printed organic electronic analog filtering elements for biosensors. Bioinks of different PEDOT:PSS (0.0, 0.1, and 0.5 wt%) manufactured into hydrogel disks using the two methods were shown to yield similarly cytocompatible substrates for attachment and differentiation of PC-12 neural progenitor cells. •Bioactive electroconductive hydrogels of PEDOT:PSS in p(HEMA-co-EGMA) were fabricated via 3-D bioprinting and microlithography.•Acuity was affected by the manufacturing technique but electrical/electrochemical properties were similar.•Fabricated constructs were cyto-compatible and supportive of PC-12 differentiation.•An in-silico model of an active low-pass filter using a 3-D bioprinted capacitor resulted in control of the cutoff frequency.