Synthesis and Bio-activities of PEDOT PSS Gelatin Layer on Indium Tin Oxide (ITO)-coated Glass

Synthesis and Bio-activities of Poly (3,4-ethylenedioxy-thiophene) (PEDOT)/Poly (styrene sulfonate) (PSS)/Gelatin Layer on Indium Tin Oxide (ITO)-coated Glass

SUI Li, PENG Binbin, HUANG Sijia, WANG Yan, JU Lihua

(School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China)

Abstract: Poly (3, 4-ethylenedioxythiophene) (PEDOT), together with its dopes, such as poly (styrene sulfonate) (PSS), has been acknowledged to have a wide range of biomedical applications as an important conducting polymer. In this study, gelatin can be polymerized into PEDOT/PSS polymers on indium tin oxide (ITO)-coated glass. PEDOT/PSS/gelatin layer on ITO-coated glass significantly decreases electrochemical impedance spectroscopy (EIS) and increases charge delivery capacity relative to the gelatin layer and bare ITO-coated glass, comparable to the PEDOT/PSS layer on ITO-coated glass. PEDOT/PSS/gelatin layer on ITO-coated glass enhances pheochromocytoma (PC 12) cell affinity, possesses a high biocompatibility and promotes PC 12 cell growth by delivery of electrical stimulation. These results suggest that gelatin can be incorporated into the PEDOT/PSS polymers through electrochemical polymerization and the PEDOT/PSS/gelatin layer on ITO-coated glass possesses high electrochemical and biological activities.

Key words: poly (3,4-ethylenedioxythiophene) (PEDOT); gelatin; electrochemistry; electrical

stimulation; PC 12 cell

DOI 10.1007/s11595-016-1426-4

1 Introduction

Conducting polymers have a wide range of applications based on their electrical, magnetic, optical and mechanical properties [1-4]. Poly (3, 4-ethylenedioxythiophene) (PEDOT) or that combined with its dopes, as one of the important conducting polymers, has been used for biomedical purposes, such as coating materials for neural implants [5,6] in the fields of biomedical sensors [7,8], drug delivery system [9,10], and tissue engineering [11,12]. PEDOT has been shown to be polymerized by chemical or electrochemical methods. During the process of polymerization, a variety of dopes (counter ions) can be incorporated into the PEDOT polymers [13]. Furthermore, the doped PEDOT polymers may possess specific properties and applications through the incorporation of appropriate doping materials. Biomedical molecules, such as [9,14,15]been reported to be incorporated into the PEDOT polymers.

produced by partial hydrolysis of collagen. Gelatin has been commonly used in food, pharmaceutics, p h o t o g r a p h y, a n d c o s m e t i c m a n u f a c t u r i n g. Furthermore, biodegradable gelatin has attractive biomedical applications in the fields of tissue engineering [16,17] and drug delivery system [18-20]. It has been reported that gelatin-based biomaterials could affect neuron functions and promote neural tissue regeneration, providing a promising application in neural engineering [21-23]. Recent research has shown that gelatin, acting as a dope or template, was incorporated into polypyrrole, one of conducting polymers, through electrochemical synthesis [24]. Whether gelatin could be polymerized into PEDOT polymers has not been investigated.

Neurons are acknowledged to be highly influenced by electrical stimuli because of their inherent nature in transmitting electro-chemical signals throughout the nervous system. Numerous studies have revealed that electrical stimulation could enhance neurite outgrowth and nerve regeneration in vitro and in vivo . Conducting polymers, together with electrical stimulation, further