Nanochemistry and biotechnology

OPTICAL SENSOR OF AMINO ACIDS BASED 
ON LIQUID CRYSTAL
Petrina R.O.1, Suberlyak S.A.1, Gubriy Z.V.1, Khomyak S.V.1, 
Sushynskyi O.Y.2, Mykytyuk Z.M.2
1 Lviv Polytechnic National University, Department of Technology of Biologically Active Substances, Pharmacy and Biotechnology, 12 Bandera str., Lviv, Ukraine.
E-mail: romanna.o.petrina@lpnu.ua
2 Lviv Polytechnic National University, Department of Electronic Devices, 
12 Bandera str, Lviv-79013, Ukraine.

We proposed to use the liquid crystal cholesteric-nematic mixture (CNM) as a sensitive medium material of optical sensor of biologically active substances in callus biomass. In order to provide high-quality, environmentally-friendly plant materials, especially for rare and endangered plants, the biotechnological method of cultivation in vitro was used. The callus biomass of plant was obtained in the Murasige-Skuga medium. It is important to monitor and quickly record the presence and quantity of specific biologically active compounds, in particular amino acids, in callus biomass and its extracts. 
A multicomponent CNM consists of cholesteric BLO-62 and nematic 5СВ liquid crystals. The selected CNM was characterized by spiral structure and minimum optical transmission at 529 nm of wavelength at room temperature. Research of interaction both crystal amino acids and their aqueous solutions with liquid crystal has been carried out. Glycine, leucine, proline, serine, phenylalanine and glutamic acid were used. We observed the change of spectral properties of CNM and linear changing of wavelength of minimum transmission versus of concentration of each amino acid; specificity of their impact has been analyzed. Extracts of callus biomass, that contain amino acids, change the spectral properties of CNM too. The results of spectral studies of the system on the base of CNM with amino acids make it possible to propose these materials to design the primary transducers optical sensors of biological substances. In this sensing element an information signal is formed due to the selective transmission of light. The technical solution for the circuit diagram of a secondary converter of optical sensors is proposed. 

1.	Sushynskyi O., Petrina R., Gubriy Z., Khomyak S., Mykytyuk Z., Novikov V. Optical sensor of flavonoids based on liquid crystal // IAPGOS.-2019.- 9, N 1.- P. 61-64.