Nanobiotechnologies for health care 

Chemical modification of polystyrene surfaces for improving performaces of ELISA microtiter plates
Shynkarenko O.V.1,  Beketov G.V. 1
1 Ye.V. Lashkaryov  Institute of Semiconductor Physics (ISP), NAS of Ukraine, Prospect Nauki, 41, Kyiv-03028, Ukraine
E-mail: o.v.shynkarenko@gmail.com

Enzyme linked immunosorbent assay (ELISA), which is based on detection of marker biomolecules (antibodies, antigens, proteins and glycoproteins) in biological samples, is currently the most common laboratory diagnostic technique. Multilateral studies are aimed at further improving its performances. One of the core issues is the optimal immobilization of capture biomolecules at the surface of microplate wells, which rely on intermolecular interactions of biomolecule nanoparticles with the solid-phase substrate [1].
Chemical modification of ELISA microtiter plates is an efficient technique for improving reproducibility, sensitivity, and concentration range of biomolecule detection. We developed a modification method based on oxidative treatment of polystyrene surface, the predominant material for manufacture of microtiter plates, in aqueous solution of ammonium persulfate, (NH4)2S2O8 [2]. Our study is aimed at characterization of immobilization efficiency of target biomolecules in dependency of physical and chemical properties of modified surface [3]. The characterization techniques include the X-ray photoelectron spectroscopy, the surface plasmon resonance spectroscopy, and wettability measurements using axisymmetrical drop shape analysis (ADSA).
The obtained results show that the low-level hydrophilization of polystyrene surface essentially improves adsorption efficiency of biomolecules compared to the non-treated surface, while the higher level has an adverse effect. Possible explanations of these observations are discussed.  

1.	Gan S.D., Patel K.R. Enzyme immunoassay and enzyme-linked immunosorbent assay // Journal of Investigative Dermatology.-2013.-133.-P. e12.
2.	Lilyanna S., Ming Wei Ng E., Shiho Moriguchi S. et al.  Variability in microplate surface properties and its impact on ELISA // JALM.-2018.-2.-P. 687-699.
3.	Beketov G., Shynkarenko O., Apatska M. Towards improving ELISA surfaces: SPR assessment of polystyrene modification efficiency for promoting immobilization of biomolecules // Anal. Biochem.-618.- 114101.