Tibor Hianik

Bio: Tibor Hianik is an academic researcher from Comenius University in Bratislava. The author has contributed to research in topics: Aptamer & Lipid bilayer. The author has an hindex of 34, co-authored 251 publications receiving 4717 citations. Previous affiliations of Tibor Hianik include Slovak Academy of Sciences & University of Colorado Denver.

Electrochemical Aptasensors – Recent Achievements and Perspectives

Abstract: This article reviews recent achievements in developing aptamer-based electrochemical biosensors (electrochemical aptasensors). Aptamers are single stranded DNA or RNA molecules with high specificity to various ligands. Their specificity is comparable and in certain cases even higher than those of antibodies. In contrast to antibodies, aptamers are prepared by an in vitro selection procedure developed simultaneously in the early 1990s by L. Gold and A. Ellington. Due to their stability and the possibility of chemical modification aptamers can be immobilized on various supports and serve as artificial receptors in biosensors. The first aptasensors developed in the second half of 1990s were based on optical detection. However, in early 2000 substantial interest arose to the development of electrochemical aptasensors. It has been shown that due to their simplicity and fast response they represent an excellent tool in practical applications. The main focus of this review is to discuss the configuration of aptamers and electrochemical methods for detecting aptamers–analyte interactions. We will also provide a brief history of aptamer development, along with molecular structure and methods of aptamer engineering. Methods for immobilizing aptamers onto a solid support are also discussed.

Membrane lipids: where they are and how they behave.

Abstract: Throughout the biological world, a 30 A hydrophobic film typically delimits the environments that serve as the margin between life and death for individual cells. Biochemical and biophysical findings have provided a detailed model of the composition and structure of membranes, which includes levels of dynamic organization both across the lipid bilayer (lipid asymmetry) and in the lateral dimension (lipid domains) of membranes. How do cells apply anabolic and catabolic enzymes, translocases and transporters, plus the intrinsic physical phase behaviour of lipids and their interactions with membrane proteins, to create the unique compositions and multiple functionalities of their individual membranes?

Conjugated polymer-based chemical sensors.

Abstract: When considering new sensory technologies one should look to nature for guidance. Indeed, living organisms have developed the ultimate chemical sensors. Many insects can detect chemical signals with perfect specificity and incredible sensitivity. Mammalian olfaction is based on an array of less discriminating sensors and a memorized response pattern to identify a unique odor. It is important to recognize that the extraordinary sensory performance of biological systems does not originate from a single element. In actuality, their performance is derived from a completely interactive system wherein the receptor is served by analyte delivery and removal mechanisms, selectivity is derived from receptors, and sensitivity is the result of analyte-triggered biochemical cascades. Clearly, optimal artificial sensory sys-

Electrochemical Biosensors - Sensor Principles and Architectures

Abstract: Quantification of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. However, converting the biological information to an easily processed electronic signal is challenging due to the complexity of connecting an electronic device directly to a biological environment. Electrochemical biosensors provide an attractive means to analyze the content of a biological sample due to the direct conversion of a biological event to an electronic signal. Over the past decades several sensing concepts and related devices have been developed. In this review, the most common traditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, and various field-effect transistor based methods are presented along with selected promising novel approaches, such as nanowire or magnetic nanoparticle-based biosensing. Additional measurement techniques, which have been shown useful in combination with electrochemical detection, are also summarized, such as the electrochemical versions of surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry, quartz crystal microbalance, and scanning probe microscopy. The signal transduction and the general performance of electrochemical sensors are often determined by the surface architectures that connect the sensing element to the biological sample at the nanometer scale. The most common surface modification techniques, the various electrochemical transduction mechanisms, and the choice of the recognition receptor molecules all influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches, such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymes into vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities for signal amplification. In particular, this review highlights the importance of the precise control over the delicate interplay between surface nano-architectures, surface functionalization and the chosen sensor transducer principle, as well as the usefulness of complementary characterization tools to interpret and to optimize the sensor response.

Aptamer-based biosensors

Abstract: Nucleic-acid aptamers have attracted intense interest and found wide applications in a range of areas. In this review, we summarize recent advances in the development of aptamer-based biosensors and bioassay methods, most of which have employed electrochemical, optical and mass-sensitive analytical techniques. Aptamers exhibit many advantages as recognition elements in biosensing when compared to traditional antibodies. They are small in size, chemically stable and cost effective. More importantly, aptamers offer remarkable flexibility and convenience in the design of their structures, which has led to novel biosensors that have exhibited high sensitivity and selectivity. Recently, the combination of aptamers with novel nanomaterials has significantly improved the performance of aptamer-based sensors, which we also review in this article. In view of the unprecedented advantages brought by aptamers, we expect aptamer-based biosensors to find broad applications in biomedical diagnostics, environmental monitoring and homeland security.