Ultrasensitive determination of carcinoembryonic antigens using a magnetoimpedance immunosensor

Abstract

Herein, a giant magnetoimpedance (GMI) sensor combined with the sandwich immunoassay was used for ultrasensitive detection of carcinoembryonic antigens (CEA). Oblong-shaped Au films were enclosed with SU-8 photoresists to form several microcavities that were treated with different concentrations of CEA.The quantification of low-concentration CEA (1 pg mL À1 -10 ng mL À1 ) was achieved by using one single GMI sensor, demonstrating a good linear relationship between the GMI response and the CEA concentration. The lower detection limit for CEA was found to be as low as 1 pg mL À1 , which provides extreme sensitivity. We observed that high-concentration CEA (>10 ng mL À1 ) can result in a cluster of Dynabeads, thereby reducing the target signals since the adjacent magnetic dipole fields canceled each other out. Target specificity of the GMI-based magnetic immunoassay has also been verified by testing nonspecific targets. The results obtained here suggest that the GMI sensor could serve as an ultrasensitive immunosensor for quantitative determination of biomarkers.

Mechanical, Electrical and Magnetic Properties of Ferrogels with Embedded Iron Oxide Nanoparticles Obtained by Laser Target Evaporation: Focus on Multifunctional Biosensor Applications

“…The first type of magnetic transducer was introduced for magnetic permeability measurements in bioanalysis by inductance measurements with a Maxwell bridge [ 4 ]. Nowadays, different magnetic effects have been shown to be capable of creating magnetic biosensors: anisotropic magnetoresistance, giant magnetoresistance, tunneling magnetoresistance, spin-valves, magnetoelastic effect, inductive effect, the Hall effect and magnetoimpedance (MI) [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ].…”

Polyacrylamide Ferrogels with Magnetite or Strontium Hexaferrite: Next Step in the Development of Soft Biomimetic Matter for Biosensor Applications

“…Over the past decade, many efforts have been made for the development of a generation of magnetic biosensors, i.e., compact analytical devices incorporating a biological sensitive element, integrated in a physicochemical transducer employing a magnetic field [ 4 , 5 ]. These devices are becoming common tools used for a variety of biomedical applications [ 6 , 7 , 8 ]. In many cases, magnetic nanoparticles (MNPs) work as biomolecular labels [ 4 , 7 ] which must be provided in the form of water-based ferrofluids [ 2 , 3 , 9 ].…”

“…These devices are becoming common tools used for a variety of biomedical applications [ 6 , 7 , 8 ]. In many cases, magnetic nanoparticles (MNPs) work as biomolecular labels [ 4 , 7 ] which must be provided in the form of water-based ferrofluids [ 2 , 3 , 9 ]. Apart from evaluating the concentration of the magnetic labels in a test solution, the detection of superparamagnetic nanoparticles (MNPs) after intracellular uptake was also tested [ 6 , 10 ].…”

Magnetoresistive Biosensors for Direct Detection of Magnetic Nanoparticle Conjugated Biomarkers on a Chip

“…45 However, biolabeling techniques of MNPs provide a favorable basis for the development of magnetic biosensors. Therefore, some welldeveloped methods for magnetic¯eld detection have been used in biosensing applications, including (i) magnetoresistive (MR) methods such as anisotropic magnetoresistance (AMR), [46][47][48][49][50][51][52] giant magnetoresistance (GMR), [53][54][55][56][57] tunneling magnetoresistance (TMR), 58,59 giant magnetoimpedance (GMI) [60][61][62][63] and (ii) nonMR methods such as those involving the use of a°ux gate sensor, Hall sensor and superconducting quantum interference device (SQUID). [64][65][66][67][68][69] Several magnetic¯eld sensors have been used in biodiagnostics, but the drawbacks of large size, low sensitivity, or high power consumption limited their use in practical applications.…”

“…Wang et al employed the stack structure of Cr/ Cu/NiFe/Cu/NiFe/Al 2 O 3 /Cr/Au as a GMI biosensor to detect the two biomarkers of carcinoembryonic antigen (CEA) and alpha-fetoprotein antigen (AFP). 62,63 The highest detectable concentrations of CEA and AFP were 10 ng/mL and 1 ng/mL, and the lowest detectable concentration of CEA and AFP achieved was 1 pg/mL. The GMI biosensor is promising for sensing low-concentration biomolecules in clinical diagnosis.…”