Detection of Galactose and Glycerophospholipids by Galactose Biosensors and Advancement Their Proficiency Using Berkelium Colloidal Nanoparticles and Poly(3,4-Ethylenedioxythiophene)-Poly(Styrenesulfonate)-Based Biosensors
Authors: Alireza Heidari 
Published: December 2021

In the current paper, galactose-oxidase enzyme is used as stabilization medium due to its more proficiency, ability for more accurate controlling the enzyme reaction, protecting against wasting of enzyme as well as simple and easy use and exchange of enzyme medium after performing some levels of surface modification and developing multi-walled carbon nanotubes (MWCNTs) on Berkelium plate. For better connecting and stabilizing the enzyme on the medium, the prepared medium is washed by high concentration sulfuric acid and nitric acid and a large volume of deionized water and for protecting enzyme from devastating effect of Berkelium and prohibiting them to become inactive, surface is covered with cystamine before stabilization. Regarding the large size of galactose-oxidase enzyme compared to surface of medium, a connective material with amid at one end and pyrine at the other end is used as transfer agent and for stabilizing this connection, the prepared medium is placed into dimethylformamide (DMF) solution for a couple of hours. Activity of stabilized enzyme at 460 (nm) wavelength recorded by spectroscope was depicted against time to evaluate its stability in various times. The prepared medium, which have a large amount of galactose-oxidase enzyme, can be used as electrode in sensors. Furthermore, galactose-oxidase electrochemical sensor is one of the best methods for detecting low amount of galactose and applying Berkelium colloidal nanoparticles as a supplementary material in the structure of biosensor can be effective for advancement its proficiency and optimum proficiency. On the other hand, in the current study, electrode biosensor entitled as modified carbon paste electrode with Berkelium colloidal nanoparticles (Bknano/CPE) is produced by carbon graphite powder, paraffin oil and Berkelium colloidal nanoparticles (24 nm) and it is compared with carbon paste electrode (CP). In semi-permeable membranes, a combination of 1 (ml) of 0.1 (M) phosphate buffer with specified pH and 10 (mg) of galactose-oxidase enzyme is placed around each electrode. In the same potential of 0.7 (V), biosensors are tested with galactose in concentration range of (0-1) (mM) and various amounts of pH (4,6,8) which lead to producing the maximum current and tracing galactose in pH=6 and concentration of 1 (M) as the optimum condition. Currentmetry induced from both biosensors are compared and it is confirmed that using Berkelium colloidal nanoparticles in the structure of (Bknano/CPE) electrode leads to increasing the conductivity and currentmerty of biosensor. In addition, qualitative and quantitative measurement of food components is of great importance due to high cost of traditional methods, in addition to tendency for more accurate and sensitive detecting of these components. galactose and glycerophospholipids are such compounds that they frequently measure. Various methods are used to detect these food elements. However, the necessity for accurate measurement of these two compounds with high sensitivity, especially for food health issue, leads to developing biological methods, especially biosensors. Among them, biosensors based on conductive polymer nanostructures, especially Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), have been recently interested due to their unique characteristics. The current paper aims to introduce and investigate the previously performed studies about Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)-based biosensors for detecting galactose and glycerophospholipids.