Nanobiotechnology for healthcare

Toward development of new optical immunosensors         based on nanostructured ZnO thin films
Alla Tereshchenko
Odesa National I.I. Mechnikov University, Pastera 42, 65023, Odesa, Ukraine. 
E-mail: alla_teresc@onu.edu.ua

ZnO-based nanostructured thin films are broadly applied as a template for biosensors due to their fundamental physico-chemical properties such as the direct wide band gap semiconductor (Eg ∼3.37eV) complemented by high surface to volume ratio of its nanostructures that has a high isoelectric point. Good biocompatibility and affinity towards biomaterials of ZnO along with its strong adsorption ability make it suitable for the immobilization of various protein-based immune complexes applied as biological recognition part in immunosensors. Excellent optical properties of ZnO, in particular, an intense room temperature photoluminescence (PL) open a great possibility to be used for optical biosensor applications [1]. Regarding to a progress in nanotechnology, the new methods have been developed to fabricate nanostructured ZnO templates with high surface area and advanced properties for biosensors, e.g. atomic layer deposition (ALD), metal organic chemical vapor deposition (MOCVD) and others. ALD is a relatively innovative technique, which allows the deposition of ultrathin metal oxide films with controlled thickness, grain size etc [2]. MOCVD is a well- known method for the formation of metal oxide thin films (as itself) and also can be used for the growth of nanorods of different size, shape and orientation on the substrate that can act as a resonator where whispering gallery modes (WGM) can be excited and utilized as a biosensor signal [3]. In this report, the influence of the immobilized proteins of an immune complex on the PL spectra of ZnO thin films formed by ALD and MOCVD will be demonstrated and discussed.  

1.	Tereshchenko A., Bechelany M., Viter R. [et.al.], Optical biosensors based on ZnO nanostructures: advantages and perspectives. A review // Sensors and Actuators B:Chemical. – 2016. – 229. – P. 664–677.
2.	A. Tereshchenko, V. Fedorenko, V. Smyntyna [et.al.], ZnO Films Formed by Atomic Layer Deposition as an Optical Biosensor Platform for the    Detection of Grapevine Virus A-type Proteins // Biosensors and Bioelectronics. – 2017. – 92. – P. 763–769.
3.	A. Tereshchenko, G. Reza Yazdi, Igor Konup [et.al.], Application of ZnO Nanorods Based Whispering Gallery Mode Resonator in Optical Immunosensors // Colloids and Surfaces B:Biointerfaces.-2021.-P.111999.