The detection of specific biomolecular interactions with micro-Hall magnetic sensors

Abstract

Detection of reagent-free specific biomolecular interactions through sensing of nanoscopic magnetic labels provides one of the promising routes to biosensing with solid-state devices. In particular, Hall sensors based on semiconductor heterostructures have shown exceptional magnetic moment sensitivity over a large dynamic field range suitable for magnetic biosensing using superparamagnetic labels. Here we demonstrate the capability of such micro-Hall sensors to detect specific molecular binding using biotin-streptavidin as a model system. We apply dip-pen nanolithography to selectively biotinylate the active areas of InAs micro-Hall devices with nanoscale precision. Specific binding of complementarily functionalized streptavidin-coated superparamagnetic beads to the Hall crosses occur via molecular recognition, and magnetic detection of the assembled beads is achieved at room temperature using phase-sensitive micro-Hall magnetometry. The experiment constitutes the first unambiguous demonstration of magnetic detection of specific biomolecular interactions with semiconductor micro-Hall sensors, and the selective molecular functionalization and resulting localized bead assembly demonstrate the possibility of multiplexed sensing of multiple target molecules using a single device with an array of micro-Hall sensors.

Magnetic sensing technology for molecular analyses

“…This coupling brings MNPs close to the sensor surface and enables unbound MNPs to be easily washed out. The bound MNPs can be detected using various magnetometers, including magnetoresistance sensors, 57,58 Hall elements 59 , and microcoils. 60 The method has been successfully applied to detect a range of biological targets, including proteins, nucleic acids and small molecules.…”

Magnetic Field Sensors Based on Microelectromechanical Systems (MEMS) Technology

“…Silicon-based Hall sensors are widely employed, due to the suitability of integration with electronics (Popovic, 1997). However, higher sensitivity sensors can be obtained with III-V technology, allowing for applications such as biomolecular function detection (Manandhar et al, 2009). Also recently, the Scanning Hall probe microscopy (SHPM) has been developed based on III-V Hall sensors, allowing for quantitative mapping of nanoscale superconducting and ferromagnetic materials (Bending et al, 2009).…”

Hall effect sensors on the basis of carbon material

“…These sensors are widely used in different fields of science, technology and medicine [9,15]. One such area is bioidentification and medical diagnostics [2,[5][6][7]. Functionalized microbeads composed of magnetic, spherical nanoparticles, usually Fe 3 O 4 with a diameter 5 to 200 nm, are employed for this purpose.…”