Resistance-Based Biosensor of Multi-Walled Carbon Nanotubes

Use of hafnium(IV) oxide in biosensors

Hafnium(IV) oxide is a material with properties that can increase the sensitivity, durability, and reliability of biosensors made from silicon dioxide and other semiconductor materials due to its high dielectric constant, thermodynamic stability, and the simplicity with which it can be deposited. This work describes the use of this material in biosensors based on field-effect transistors to detect ions and DNA, in immunosensors to detect an antigen-antibody complex, its use as a contrast material in computed tomography scans and the possibility of using it in optic biosensors in the infrared region. Its low cost and versatility in the field of biosensors is underscored.

Magnetic Printing of a Biosensor: Inexpensive Rapid Sensing To Detect Picomolar Amounts of Antigen with Antibody-Functionalized Carbon Nanotubes

When an antibody (Ab) is immobilized on its surface, a carbon nanotube (CNT) becomes a biosensor that detects the corresponding antigen (Ag) because Ag-Ab complexes formed on the CNT surface moderate the current flow through it. We synthesized a biological ink containing CNTs that are twice functionalized, first with magnetic nanoparticles and thereafter with the anti-c-Myc monoclonal Ab. The ink is pipetted and dynamically self-organized by an external magnetic field into a dense electrically conducting sensor strip that measures the decrease in current when a sample containing c-Myc Ag is deposited on it. Prototypes are rapidly fabricated materials that cost less than 20 cents (Canadian) for each sensor. With larger current decreases due to real-time specific Ag-Ab binding for higher c-Myc concentrations, the biosensor distinguishes between picomolar c-Myc concentrations within a minute, offering proof of concept of a simple, rapid, economical, and sensitive method to detect specific molecules recognizable by Abs.