Electrochemical Liposome-Based Biosensors for Nucleic Acid Detection
MicroRNAs (miRNAs) are intensely studied as candidates for diagnostic and prognostic clinical biomarkers. Faradic impedance spectroscopy (EIS) and differential pulse voltammetry (DPV), coupled to disposable gold electrodes and enzyme amplification of the
- PDF / 94,788 Bytes
- 4 Pages / 439.37 x 666.14 pts Page_size
- 41 Downloads / 248 Views
1
Introduction
MicroRNAs (miRNAs) are a class of small noncoding RNAs with approximately 22 nucleotides in length that play important roles in different biological processes like cell differentiation and prolification and regulation of protein translation. An abnormal miRNA expression (overexpression or down-expression) has been linked to cancer [1, 2] and other diseases. The first evidence of involvement of miRNAs in human cancer came from molecular studies which revealed that two miRNAs, mir-15 and mir-16, were involved in chronic lymphocytic leukemias [3]. Following this initial discover, other researches were focused on the investigation of miRNA expression deregulation in human cancer. For example, mir143 and mir145 are downregulated in colon carcinomas [4] and mir122 is involved in breast cancer [5]. Because of this, the study of miRNAs has become important and necessary for many fields in science, and in particular, they represent good candidates for diagnostic and prognostic biomarkers. Moreover, the ability to selectively regulate protein activity through miRNAs could enable treatment of many forms of cancer and other serious illness. In the previous years, researchers have been challenged to push the sensitivity of analytical bioassays down to subnanomolar values while keeping these procedures as simple, reliable, and cost-effective as possible. In particular, the formation of supramolecular assemblies and the use of enzymes to enhance the sensitivity of genoassays have been the subject of many research efforts [6]; functionalized
D. Voccia • F. Bettazzi • I. Palchetti (*) Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy e-mail: [email protected]; [email protected] C. Di Natale et al. (eds.), Sensors and Microsystems: Proceedings of the 17th National Conference, Brescia, Italy, 5-7 February 2013, Lecture Notes in Electrical Engineering 268, DOI 10.1007/978-3-319-00684-0_34, © Springer International Publishing Switzerland 2014
179
180
D. Voccia et al.
liposomes have been exploited as nanostructures for genosensors [7, 8]. Outstandingly low detection limits were achieved. In this paper, two electrochemical methods based on liposome amplification for miRNA detection are reported. Disposable screenprinted gold electrodes were used as transducers using DPV and EIS. A thiolated DNA capture probe was immobilized onto gold electrode surfaces (the biosensing platform). Biotinylated RNA was then hybridized with the specific capture probes. The biosensing platform was then incubated with the enzymatic label. Biotin-labeled liposomes were used as a functional tether for the enzyme and, owing to their large surface area, are capable of carrying a large number of enzyme molecules. The product of the enzymatic reaction was electrochemically monitored, using α-naphthyl phosphate for DPV and BCIP/NBT Liquid Substrate System for EIS.
2 2.1
Experimental Chemicals
Streptavidin–alkaline phosphatase, α-naphthyl phosphate, Streptavi
Data Loading...
