Three-Dimensional-Printed Polyethylene Glycol Diacrylate-Polyaniline Composites by In Situ Aniline Photopolymerization: An Innovative Biomaterial for Electrocardiogram Monitoring Systems

Abstract

Three-dimensional (3D) printing technology is one of the additive manufacturing (AM) technologies that brings exciting prospects to the realm of conjugated polymers (CPs) and organic electronics through vastly enhanced design flexibility, structural complexity, and environmental sustainability. However, the use of 3D printing for CPs is still at early stages and remains full of challenges. Therefore, an interesting approach is to produce 3D-printed electrically conductive materials by exploiting the photopolymerization of conjugated monomers directly during the stereolithography process. The idea proposed in this work is to formulate a printable ink containing aniline able to photopolymerize within the insulating printable polyethylene glycol diacrylate (PEGDA) polymeric matrix directly during the 3D-printing process. The produced PEGDA-polyaniline (PANI) composites exhibit suitable morphological and structural features, as well as electrical and electrochemical performances potentially useful for various soft electronics applications. As a proof of concept, the 3D printed PEGDA-PANI samples are employed as a soft electrode in an electrocardiogram (ECG) device, and the efficiency is monitored under real-time conditions. The collected data exhibit reproducible ECG patterns, opening the way to 3D printed PEGDA-PANI electrodes for biosignal monitoring applications.

Role of Precursors and Doping Agents in Producing 3D-Printed PEGDA–PDANI Electroactive Composites by an In Situ Polymerization Approach

“…The cross-sectional image of a cut PP-Cl disc (Figure c) undoubtedly evidences that the PDANI phase has uniformly grown within the PEGDA matrix, emphasizing that the proposed in situ synthesis method permits the effective formation of a composite material. The cross-sectional SEM image (Figure d) highlights the multilayered architecture of PEGDA–PDANI samples, obtained by the typical layer-by-layer deposition of 3D printing procedure . Analogously, the smooth surface exhibited by this sample is in line with the high-quality surface finishing commonly achieved by means of the light-induced 3D printing technique .…”

“…As is well established in the literature, during an electrochemical event, the structural changes, associated with the electron transfers from and onto the backbone of a CP, are typically accompanied by ion exchanges with the surrounding electrolytic solution for charge balancing. The mechanisms underlying these processes can involve anion or cation exchanges, and for PDANI phase they can be, respectively, described by eqs and , P D A N I + n normalA − + n H 2 normalO ⇌ ( P D A N I ( n + ) : ( normalA − ) n : n normalH 2 O ) + n normale − P D A N I : false( A − false) n : false( C + false) n ⇌ normalP normalD normalA normalN normalI n + : false( A − false) n + n normale − + n normalC + …”

“…27,28 PANI films or composites have found large use in bioelectronics as main element in sensing, 27,29−31 memory, 32,33 and such devices. 11,31,34 In this view, the exploration of different deposition methods, 3D geometrical factors, and innovative synthesis protocols may pave the way for the exploitation of PANI properties in several applications. 11,15,26,35−37 Although the synthetic protocols starting from the ANI monomer are consolidated and effective, 7,29,38−40 a series of controversies are related to the use of this reagent, including a potential toxicity.…”

Organic Bioelectronics Development in Italy: A Review

“…At higher doping levels, these charged molecular defects introduce energy states within the electronic band gap, tuning the charge transport properties of the material into a quasi-metallic regimen [ 19 ]. Moreover, the ion exchange mechanisms induced by the involvement of the dopant ions during the redox processes allows for CPs to have ionic conduction properties [ 21 ].…”

Electrically conductive scaffolds mimicking the hierarchical structure of cardiac myofibers

“…Starting from previous studies on innovative methods to prepare biomaterials and biosystems 21 – 23 , the main goal of the present study was to develop electrically conductive scaffolds mimicking the hierarchical orientation of cardiac myofibers using 3D printing projection micro-stereolithography approach from a technical perspective.…”