Water-soluble ionic polythiophenes for biological and analytical applications

Abstract

Ionic polythiophenes are important conjugated polymers because of their excellent optical properties and water solubility. They are classified as cationic, anionic and zwitterionic conjugated polyelectrolytes. This review article describes concisely their biological and analytical applications. The specific detection of different negatively charged biomolecules such as DNA and adenosine triphosphate, anions like halides and toxic pseudo-halide (CN − ) and environmental pollutants, e.g. surfactants, is discussed. The conformational changes of cationic polythiophenes (CPTs) induced by various analytes due to formation of ionic conjugates and the cooperative responses of all segments cause dominant signal amplification even in the presence of a small perturbation. In addition, reactive oxygen scavenging, antimicrobial photosensitizing and cell imaging applications of CPTs are documented. Use of anionic polythiophenes for sensing of protamine and cations like Cu 2+ and Ca 2+ is also discussed. Finally, sensing of DNA, peptides and surfactants by zwitterionic polythiophenes is included. The concluding part discusses future prospects.

Colorimetric detection of Hg2+ using a mixture of an anionic azo dye and a cationic polyelectrolyte in aqueous solution

“…). The K a value is in the range of those ( K a = 4.9 × 10 2 –6.1 × 10) previously reported for colorimetric chemosensors toward Hg 2+ …”

“…The detection of heavy metal ions is of significance for analytical, biomedical and environmental chemistry due to their adverse effects on human health and the global environment. [1][2][3][4][5][6][7][8][9][10][11][12] Among heavy metal ions, mercury is considered as one of the most extremely toxic and dangerous metal ions for the environment and human health because of its easy accumulation and difficult biodegradation. [13][14][15] Mercury has been widely used in batteries, paints and electronic equipment, leading to an increase of its release to the environment.…”

Flexible and conductive multilayer films based on the assembly of PEDOT:PSS and water soluble polythiophenes

“…Compared to neutral conjugated polymers, CPEs are soluble in polar solvents such as water and methanol, which allows their use in a wide range of applications such as biological sensors [2,3], biomedical imaging [4,5], photovoltaic cells [6] and organic light-emitting devices [7,8]. Since the conformation of the polymer backbone directly influences the optoelectronic properties of CPEs, understanding and developing self-assembly strategies to control the CPE conformation is of crucial importance [9,10].…”

Novel polythiophene derivative for dual-channel cell imaging

“…[23][24][25][26] WSCPs have several advantages for in vitro/vivo bioimaging applications, such as high uorescence brightness, good photostability, and easy modulation of the absorption and emission spectra. [27][28][29] Targeted recognition and imaging of cells could be achieved by attaching various specic recognition groups to the side chains of WSCPs. [30][31][32] For example, in 2017, Jiang and coworkers covalently attached galactose to the side chain of poly(p-phenyleneethynylene), and achieved targeted imaging of hepatoma cell.…”