Lab-on-a-Chip Systems for Aptamer-Based Biosensing.

Niazul I Khan,Edward Song

doi:10.3390/mi11020220

Abstract

Aptamers are oligonucleotides or peptides that are selected from a pool of random sequences that exhibit high affinity toward a specific biomolecular species of interest. Therefore, they are ideal for use as recognition elements and ligands for binding to the target. In recent years, aptamers have gained a great deal of attention in the field of biosensing as the next-generation target receptors that could potentially replace the functions of antibodies. Consequently, it is increasingly becoming popular to integrate aptamers into a variety of sensing platforms to enhance specificity and selectivity in analyte detection. Simultaneously, as the fields of lab-on-a-chip (LOC) technology, point-of-care (POC) diagnostics, and personal medicine become topics of great interest, integration of such aptamer-based sensors with LOC devices are showing promising results as evidenced by the recent growth of literature in this area. The focus of this review article is to highlight the recent progress in aptamer-based biosensor development with emphasis on the integration between aptamers and the various forms of LOC devices including microfluidic chips and paper-based microfluidics. As aptamers are extremely versatile in terms of their utilization in different detection principles, a broad range of techniques are covered including electrochemical, optical, colorimetric, and gravimetric sensing as well as surface acoustics waves and transistor-based detection.

Highlights

According to the IUPAC (International Union of Pure and Applied Chemistry) definition, a biosensor is “a self-contained integrated device which is capable of providing specific quantitative or semiquantitative analytical instrumentation using a biological recognition element which is in direct spatial contact with a transducer element [1].” In general, a biosensor can be broadly defined as a device that converts a physical, chemical or biological event into a measurable signal
This review summarizes the current state-of-the-art LOC systems that utilize aptamer-based biosensors
The integration of aptasensors to various forms of microfluidics and paper-based analytical devices have further increased the versatility of aptamers

Summary

Introduction

According to the IUPAC (International Union of Pure and Applied Chemistry) definition, a biosensor is “a self-contained integrated device which is capable of providing specific quantitative or semiquantitative analytical instrumentation using a biological recognition element (biochemical receptor) which is in direct spatial contact with a transducer element [1].” In general, a biosensor can be broadly defined as a device that converts a physical, chemical or biological event into a measurable signal. In the microfluidic system Sh is much smaller due to the small channel geometry d, and diffusive transport dominates the convective mass transport. This diffusive effect can be used in the passive mixing of two or more fluids as well as in the separation of particles based on the size in the microfluidic channel [36]. A consequence of this flow type is that two or more layers of fluid can flow side-by-side without any mixing other than by diffusive transport of their constituent molecular and particulate components [36] Another significant property that distinguishes microscale systems from macroscale systems is the Bond number (Bo). Small d results in a very low Bond number, which indicates the dominance of surface tension forces over body forces

Microfluidic Aptasensors Based on Electrochemical Detection

Amperometric Detection

Fluorescence Detection

Microfluidic Aptasensor Based on Mass-Based Detection

Findings

Conclusion and Outlook