The synthesis and characterization of a series of monothiophenes and terthiophenes bearing amino acids are reported. The reaction of a thiophene, substituted in position 3 by either a carboxylic acid or an acetic acid moiety, with an alanine methyl ester in the presence of hydroxybenzotriazole (HOBt) and N,N′-dicyclohexylcarbodiimide (DCC) affords several mono/terthiophene-alanine methyl esters. The latter were deprotected to form the corresponding carboxylic acids. Terthiophenes have been prepared in good yields via a Stille cross coupling reaction, using a dibromothiophene–alanine methyl ester and tri-butyl stannyl thiophene. The newly prepared monomers are very stable in air and in the presence of organic solvents. The optical and electrochemical properties of the monomers and their corresponding polymers were also examined using cyclic voltammetry and indium tin oxide (ITO) electrodes.

A poly(terthiophene) pendant verdazyl radical was prepared via the electrochemical oxidation of either the parent radical or its precursor. Cyclic voltammetry showed a positive shift of the verdazyl radical oxidation potential in the corresponding electroactive poly(verdazyl radical-terthiophene).

π-conducting materials such as chiral polythiophenes exhibit excellent electrochemical stability in doped and undoped states on electrode surfaces (chiral electrodes), which help tune their physical and electronic properties for a wide range of uses. To overcome the limitations of traditional surface immobilization methods, an alternative pathway for the detection of organic and bioorganic targets using chiral electrodes has been developed. Moreover, chiral electrodes have the ability to carry functionalities, which helps the immobilization and recognition of bioorganic molecules. In this review, we describe the use of polythiophenes for the design of chiral electrodes and their applications as electrochemical biosensors.