Preparation of Ultrathin and Degradable Polymeric Films by Electropolymerization of 3-Amino-L-Tyrosine

The resource intensive and environmentally unfriendly synthesis, recycling and disposal of today’s plastics has sparked interest in greener polymer processing. Bioderived polymers are one of many current areas of research that show promise for a sustainable future. One bioderived polymer that has been in the spotlight for the past decade due to its unique properties is polydopamine (PDA). Its ability to adhere to virtually any surface showing high stability in a wide pH range from 2-10 and in several organic solvents makes it a suitable candidate for several applications ranging from medical devices, coatings to biosensing applications. However, its strong and broad light absorption limits many applications that rely on transparent material, moreover fluorescence applications are limited by the high quenching efficiency of PDA. Therefore, new bioderived polymers that share similar features as PDA without fluorescent quenching are highly desirable. In this study, the electropolymerization of a bioderived analogue of dopamine, 3-amino-L-tyrosine (ALT) is demonstrated. The properties of the resultant polymer, poly-amino-L-tyrosine (p-ALT), exhibit several characteristics complementary to or even exceeding those of PDA and of its analog, poly-norepinephrine (p-NorEp), rendering p-ALT attractive for the development of sensors and photoactive devices. Cyclic voltammetry, spectroelectrochemistry and electrochemical quartz crystal microbalance have been applied to study the electrodeposition of this material and the resulting polymeric films have been compared to PDA and p-NorEp. Impedance spectroscopy revealed increased ions permeability of p-ALT with respect PDA and p-NorEp. Moreover reduced fluorescence quenching of p-ALT film was achieved supporting its application as coating for biosensors, organic semiconductors and new nanocomposite materials.