Abstract: |
Layer-by-layer assembled CNTs customized with biopolymers has recently attracted a great attention as a simple, robust and inexpensive method for creating nanocomposite thin films with a high degree of control that may provide potentially powerful interfaces for multiple applications, including but not limited to biomedicine and biosensing. Intercalation of oppositely charged polymers and catalytically active proteins on the CNT surface allow assembling of unique nanointerfaces with the ability to detect single or multiple analytes (Hitzky et al., 2005; Kumar and Swetha, 2010; Dujardin and Mann, 2002; Palin et al., 2005; Geetha et al., 2006; Yan et al., 2010; Riccardi et al., 2006; Darder et al., 2005; Liu et al., 2004; Raravikar et al., 2005; Du et al., 2004; Katz and Willner, 2004; Wang, 2005; Allen et al., 2007; Ghindilis et al., 1997; Joshi et al., 2005; Chikkaveeraiah et al., 2009; Wang et al., 2006). The aim of this study is to design of multifunctional systems for the detection of numerous compounds, such as glucose and OP neurotoxins, in one platform using nanocomposite interface. A redox enzyme glucose oxidase (GOX) and organophosphate hydrolase (OPH), a phosphotriesterase catalyzing degradation of phosphorus-containing toxins and pesticides, were covalently immobilized on the multiwalled carbon nanotube (MWNT) surface using EDC/NHS chemistry. Layer-by-layer assembly (LBL) of oppositely charged CNTs customized with different biopolymers were examined on several substrates including glass or silicon slides and glassy carbon electrode. The interface assembly were characterized using Thermogravimetric analysis, Raman spectroscopy, Fourier Transform Infrared Spectroscopy, and scanning electron microscopy (SEM). The catalytic activity of the biopolymer layers were characterized using absorption spectroscopy and electrochemical analysis. Experimental results show that this approach yields an easily fabricated catalytic multilayer with well-defined structures and properties for biosensing applications whose interface can be reactivated via a simple procedure. |