Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7234055 | Biosensors and Bioelectronics | 2013 | 6 Pages |
Abstract
Functionalized magnetic nanoparticles (mNPs) have shown promise in biosensing and other biomedical applications. Here we use functionalized mNPs to develop a highly sensitive, versatile sensing strategy required in practical biological assays and potentially in vivo analysis. We demonstrate a new sensing scheme based on magnetic spectroscopy of nanoparticle Brownian motion (MSB) to quantitatively detect molecular targets. MSB uses the harmonics of oscillating mNPs as a metric for the freedom of rotational motion, thus reflecting the bound state of the mNP. The harmonics can be detected in vivo from nanogram quantities of iron within 5Â s. Using a streptavidin-biotin binding system, we show that the detection limit of the current MSB technique is lower than 150Â pM (0.075Â pmole), which is much more sensitive than previously reported techniques based on mNP detection. Using mNPs conjugated with two anti-thrombin DNA aptamers, we show that thrombin can be detected with high sensitivity (4Â nM or 2Â pmole). A DNA-DNA interaction was also investigated. The results demonstrated that sequence selective DNA detection can be achieved with 100Â pM (0.05Â pmole) sensitivity. The results of using MSB to sense these interactions, show that the MSB based sensing technique can achieve rapid measurement (within 10Â s), and is suitable for detecting and quantifying a wide range of biomarkers or analytes. It has the potential to be applied in variety of biomedical applications or diagnostic analyses.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Xiaojuan Zhang, Daniel B. Reeves, Irina M. Perreard, Warren C. Kett, Karl E. Griswold, Barjor Gimi, John B. Weaver,