ORIGINAL PAPER Improvement of amperometric laccase biosensor using enzyme-immobilized gold nanoparticles coupling with ureasil polymer as a host matrix T. Kavetskyy 1,2 & N. Stasyuk 3 & O. Smutok 3 & O. Demkiv 3 & Y. Kukhazh 1 & N. Hoivanovych 1 & V. Boev 4 & V. Ilcheva 4 & T. Petkova 4 & M. Gonchar 3 Received: 12 October 2018 /Accepted: 22 April 2019 /Published online: 7 May 2019 # Springer Nature Switzerland AG 2019 Abstract Synthesis of gold nanoparticles (Au-NPs) was performed using method of an inorganic chemical reduction. The synthesized Au- NPs showed an intensive surface plasmon resonance band at 525 nm that is typical for corresponding Au-NPs reported in literature. The structural and morphology characterizations of the obtained Au-NPs were carried out using SEM, AFM, TEM, and X-ray spectral analysis. The possibility of usage of Au-NPs as a carrier for covalent immobilization of commercial laccase and the combination of the obtained bio-Au-NPs with ureasil polymers as host matrixes for formation of bio-nanocomposite films was studied. The prospect of using the obtained bio-nanocomposite films in biosensor technologies in order to improve the bioanalytical characteristics of sensory elements has been proved. Keywords Laccase . Gold nanoparticles . Organic-inorganic ureasil polymer . Amperometric biosensor Introduction Technogenic pressure on the environment significantly affects the pollution of water resources. The one of the most danger- ous pollutants of wastewater are phenolic xenoestrogens. They are a matter of industrial origin in the human body, capable of causing effects similar to the effects of high doses of a natural hormone estrogen [1, 2]. Xenoestrogens, classi- fied as carcinogens, cause disruption of the endocrine system of human and animals [3–6]. On the other hand, it is known fact that laccase (EC 1.10.3.2 p-diphenol: benzenediol oxygen oxidoreductase from Trametes versicolor) is a copper- containing enzyme which is able to catalyze the oxida- tion of several phenolic compounds and aromatic amines [7]. In a typical laccase reaction, a phenolic substrate is exposed to a single electronic oxidation with the formation of aril radical that in the next stage of the enzymatic reaction is converted into a quinone. Laccase does not need a hydrogen peroxide as a co-substrate or additional co-factors for fermentation reaction that makes it a good perspective in fabrication of biosensors for monitoring an amount of phenol-containing compounds, including phenol-containing xenoestrogens. Nowadays, nanotechnology approaches have been successfully used for improvement of functional proper- ties of the enzymatic sensors. The specific properties of nanomaterials (nanoparticles, NPs) are high chemical activity, due to their increased ability to ionic or atomic exchange and ability to surface bond adsorption [8]. In the chemical synthesis of NPs, various variants are used that differ in the type of reagent and system in which the process is carried out [9]. Available methods of NP synthesis, as well as their affinity for many biological molecules, make them prospective candidates for research in sensor technolo- gies [10]. For biotechnological processes, it is particularly important to obtain bio-nanomaterials with improved catalytic properties [11]. * T. Kavetskyy kavetskyy@yahoo.com 1 Drohobych Ivan Franko State Pedagogical University, 82100 Drohobych, Ukraine 2 The John Paul II Catholic University of Lublin, 20-950 Lublin, Poland 3 Institute of Cell Biology, National Academy of Sciences of Ukraine, 79005 Lviv, Ukraine 4 Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria Gold Bulletin (2019) 52:79–85 https://doi.org/10.1007/s13404-019-00255-z