Ultrasensitive Magnetic Nanoparticle Detector for Biosensor Applications

Abstract

Ta/Ru/Co/Ru/Co/Cu/Co/Ni80Fe20/Ta spin-valve giant magnetoresistive (GMR) multilayers were deposited using UHV magnetron sputtering and optimized to achieve a 13% GMR ratio before patterning. The GMR multilayer was patterned into 12 sensor arrays using a combination of e-beam and optical lithographies. Arrays were constructed with 400 nm × 400 nm and 400 nm × 200 nm sensors for the detection of reporter nanoparticles. Nanoparticle detection was based on measuring the shift in high-to-low resistance switching field of the GMR sensors in the presence of magnetic particle(s). Due to shape anisotropy and the corresponding demag field, the resistance state switching fields were significantly larger and the switching field distribution significantly broader in the 400 nm × 200 nm sensors as compared to the 400 nm × 400 nm sensors. Thus, sensor arrays with 400 nm × 400 nm dimensions were used for the demonstration of particle detection. Detection of a single 225 nm Fe3O4 magnetic nanoparticle and a small number (~10) of 100 nm nanoparticles was demonstrated. With appropriate functionalization for biomolecular recognition, submicron GMR sensor arrays can serve as the basis of ultrasensitive chemical and biological sensors.

Recombinant expression, characterization, and quantification in human cancer cell lines of the Anaplastic Large-Cell Lymphoma-characteristic NPM-ALK fusion protein

“…We are separately working on adapting our immunoassay to magnetic-based detection with greatly enhanced detection sensitivity and matrix-insensitivity. Based on preliminary experiments, we believe there is a realistic possibility we will be able to detect NPM-ALK fusion protein in buffy coat lysates from peripheral blood samples, instead of (invasive) tissue biopsies using our (under-development) magnetic immunosensors 48,49 and/or other methods. Thus we believe that an ultrasensitive immunoassay coupled to a matrix-insensitive magnetic reader may serve as a complementary diagnostic test to current procedures and also be used for minimal residual disease detection, recurrence, and treatment efficacy monitoring in patients harboring the NPM-ALK fusion.…”

Biosensing Using Magnetic Particle Detection Techniques

“…More recently, GMR has found use as a magnetoresistance-based, solid-state magnetic sensor. Among the different types of sensing methods, the spin valve provides higher sensitivity with a micron-sized design [ 151 , 152 , 153 ]. A spin-valve GMR sensor consists of an artificial magnetic structure with alternating ferromagnetic and nonmagnetic layers.…”

“…Spin-valve type GMR sensors have become popular as biochips due to their better linearity for quantification [ 20 , 153 ]. Fine-tuning the architectures of sensor arrays has been reported to improve the detection limit; one approach is to adjust the dimensions of sensor array for the detection of individual MPs [ 152 ]. Another approach is to use synthetic antiferromagnetic particles, which are typically fabricated as double layers of Co 90 Fe 10 separated by a nonmagnetic spacer layer of Ru with almost zero magnetic remanence and high magnetic moment.…”

Engineered Protein-Driven Synthesis of Tunable Iron Oxide Nanoparticles as T1 and T2 Magnetic Resonance Imaging Contrast Agents

“…Among the different types of nanomaterials, magnetic nanoparticles (MNPs) have aroused great interest because of their widespread scientific applications (data and energy storage, , catalysis, , environmental remediation, , magnetic fluids, , electronics, , and biomedicine , ). Especially, iron oxide nanoparticles (IONPs) have been extensively pursued in biomedicine owing to their physicochemical properties, stability, and biocompatibility. − In this context, IONPs have been frequently used in different biomedical applications such as MRI, , magnetic particle imaging (MPI), , bioseparation, , biosensing, , and therapy (hyperthermia, , drug, , and gene delivery , ).…”

“…Especially, iron oxide nanoparticles (IONPs) have been extensively pursued in biomedicine owing to their physicochemical properties, stability, and biocompatibility. 12 − 14 In this context, IONPs have been frequently used in different biomedical applications such as MRI, 15 , 16 magnetic particle imaging (MPI), 17 , 18 bioseparation, 19 , 20 biosensing, 21 , 22 and therapy (hyperthermia, 23 , 24 drug, 25 , 26 and gene delivery 27 , 28 ).…”