ABSTRACT
Conducting polymers (CPs) are composed of distinct macromolecular units bonded to each other by weak van der Waals, dipolar, and supramolecular π–π interactions, which make them easier to be processable by solution-based techniques when compared to their “hard” inorganic counterparts. The most common CPs include polyacetylene (PA), polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh), poly(para-phenylene) (PPP), poly(phenylenevinylene) (PPV), and polyfuran (PF). They have been synthesized by a variety of methods such as chemical oxidation, electrochemical polymerization, vapor phase synthesis, hydrothermal, solvothermal, template-assisted, electrospinning, self-assembly, and photochemical methods, inclusion method, the solid-state method, and plasma polymerization. These polymers have attracted considerable attention in various optical imaging modalities like fluorescence, chemi/bioluminescence, and photoacoustic imaging owing to their remarkable photostability, high fluorescence brightness, sharp NIR absorbance peaks, ease of modification, and low cytotoxicity. The hydrophilicity can be introduced to CPs by attaching a charged side chain, which enables it to have light-harvesting properties and signal amplification effect providing its potential application in biomedical engineering as a diagnostic agent. With the emergence of CPs in the field of nanomedicine, diagnosis of various diseases can be made possible at the molecular and cellular level with superior therapeutic outcomes. Thus, in this chapter, we focus on the biomedical applications of CPs, including tissue imaging such as lymph nodes, vascular structures, and tumors.
