Biofunctionalization of polydioxythiophene derivatives for biomedical applications

Abstract

The polydioxythiophenes PEDOT and more recently ProDOT have emerged as champion materials in the field of organic bioelectronics, both in the domain of biosensing and also for integration with living cells (both in vitro and in vivo). Although polydioxythiophenes in their pristine forms have shown great promise for bioelectronics, in order to broaden the spectrum of applications, a biofunctionalization step is essential. In this review we summarise the methods that have been used thus far to biofunctionalize polydioxythiophenes in an effort to improve the biotic/abiotic interface. We provide an introduction to this class of materials, focusing particularly on the different methods of synthesis (chemical oxidative polymerization, vapor phase polymerization or direct electrochemical polymerization) and discuss the implications of synthesis on biofunctionalization. Rather than provide an exhaustive review, we chose to highlight key examples of biofunctionalization techniques for polydioxythiophenes for specific biomedical applications. Finally, we conclude with a brief discussion of the importance of biofunctionalization methods in future bioelectronics applications, and some ideas for future directions in this field. Figure 1: Structures of polydioxythiophene monomers and dopants. a) structure of EDOT monomer and modified EDOT with different pendant groups (carboxyl shown). b) structure of ProDOT monomer and modified ProDOT with different pendant groups (ProDOT-ene shown) c) Usual dopants such as polystyrene sulfonate (PSS) polymer, tosylate (TOS) monomer, and perchlorate monomer CPs came to the forefront in 1976 with research done by Alan MacDiarmid, Hideki Shirakawa and Alan Heeger, and have since been shown to display many desirable characteristics for a variety of applications. 3,4 An important example is their mixed conductivity; In CPs, electrons move primarily along the conjugated backbone of the polymer, but charge hopping between chains also occurs. CPs typically have an open microstructure that allows for facile ionic transport. This mixed (electronic and ionic) conductivity has been shown to be very useful for certain biomedical applications. 5 The most frequently used CPs for biomedical applications include polypyrrole, polyaniline and polythiophenes. 6 Although polypyrrole lead

Organic transistor platform with integrated microfluidics for in-line multi-parametric in vitro cell monitoring

“…Dual advantages of the use of the OECT used as a multiparametric in-line sensor are the biocompatibility of the PEDOT: PSS active layer (related to hydrogel-like properties) 27 as well as a flexibility to customize the transistor configuration, for example, planar or vertical geometry with regard to the requirements of the in vitro model under investigation. Integration of the devices on flexible substrates has already been demonstrated 29 and 3D electrode formats are in progress 63,64 .…”

“…The transistor channel is typically in direct contact with an electrolyte within which a gate electrode is also present. Poly(3,4-ethylene-dioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) is a conducting polymer that is commonly employed as the active layer of OECTs, due to its easy processability, chemical tunability, and biocompatibility [26][27][28] . Solution processability of this material implies a flexibility of design essential for integration of devices with state of the art in vitro models, and indeed, incorporation of microfluidics.…”

A highly sensitive molecular structural probe applied to in situ biosensing of metabolites using PEDOT:PSS

“…Poly(3,4‐ethylene dioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) is one of the most commonly used CPs for bioelectronic applications. This is due to its mixed ionic and electronic conductivity and biocompatibility allowing its direct interfacing with aqueous environments and biological systems while preserving its electrical properties (Strakosas, Wei, Martin, & Owens, ). One notable example of its implementation into novel device configurations for bioelectronics, is the organic electrochemical transistor (OECT; Rivnay et al, ).…”

Conducting Polymer‐Based Biocomposites Using Deoxyribonucleic Acid (DNA) as Counterion

“…Biofunctionalization of conducting polymers has been proposed to improve their biocompatibility and functionality in specific biomedical applications where they interface with living cells . Peng et al reviewed the immobilization of DNA sample fragments on the films of conducting polymers including PEDOT and PPy film for DNA sensing .…”