Anodized aluminum oxide-based capacitance sensors for the direct detection of DNA hybridization

Electrochemical DNA hybridization sensors based on conducting polymers

Conducting polymers (CPs) are a group of polymeric materials that have attracted considerable attention because of their unique electronic, chemical, and biochemical properties. This is reflected in their use in a wide range of potential applications, including light-emitting diodes, anti-static coating, electrochromic materials, solar cells, chemical sensors, biosensors, and drug-release systems. Electrochemical DNA sensors based on CPs can be used in numerous areas related to human health. This review summarizes the recent progress made in the development and use of CP-based electrochemical DNA hybridization sensors. We discuss the distinct properties of CPs with respect to their use in the immobilization of probe DNA on electrode surfaces, and we describe the immobilization techniques used for developing DNA hybridization sensors together with the various transduction methods employed. In the concluding part of this review, we present some of the challenges faced in the use of CP-based DNA hybridization sensors, as well as a future perspective.

NANOPOROUS MEMBRANE FOR BIOSENSING APPLICATIONS

Synthetic nanoporous membranes have been used in numerous biosensing applications, such as glucose detection, nucleic acid detection, bacteria detection, and cell-based sensing. The increased surface affinity area and enhanced output sensing signals make the nanoporous membranes increasingly attractive as biosensing platforms. Surface modification techniques can be used to improve surface properties for realizable bioanalyte immobilization, conjugation, and detection. Combined with realizable detection techniques such as electrochemical and optical detection methods, nanoporous membrane–based biosensors have advantages, including rapid response, high sensitivity, and low cost. In this paper, an overview of nanoporous membranes for biosensing application is given. Types of nanoporous membranes including polymer membranes, inorganic membranes, membranes with nanopores fabricated using nanolithography, and nanotube-based membranes are introduced. The fabrication techniques of nanoporous membranes are also discussed. The key requirements of nanoporous membranes for biosensing applications include surface functionality for bioanalyte immobilization, biocompatibility, mechanical and chemical stability, and anti-biofouling capability. The recent advances and development of nanoporous membrane–based biosensors are discussed, especially for the sensing mechanism and surface functionalization strategies. Finally, the challenges and future development of nanoporous membrane for biosensing applications are discussed.