An inexpensive, fast and sensitive quantitative lateral flow magneto-immunoassay for total prostate specific antigen.

We describe the detection characteristics of a device the Resonant Coil Magnetometer (RCM) to quantify paramagnetic particles (PMPs) in immunochromatographic (lateral flow) assays. Lateral flow assays were developed using PMPs for the measurement of total prostate specific antigen (PSA) in serum samples. A detection limit of 0.8 ng/mL was achieved for total PSA using the RCM and is at clinically significant concentrations. Comparison of data obtained in a pilot study from the analysis of serum samples with commercially available immunoassays shows good agreement. The development of a quantitative magneto-immunoassay in lateral flow format for total PSA suggests the potential of the RCM to operate with many immunoassay formats. The RCM has the potential to be modified to quantify multiple analytes in this format. This research shows promise for the development of an inexpensive device capable of quantifying multiple analytes at the point-of-care using a magneto-immunoassay in lateral flow format.

The dual role of paramagnetic particles for integrated lysis and measurement in a rapid immunoassay for intracellular proteins.

A novel, integrated lysis and immunoassay methodology and system for intracellular protein measurement are described. The method uses paramagnetic particles both as a lysis agent and assay label resulting in a rapid test requiring minimal operator intervention, the test being homogeneous and completed in less than 10 min. A design study highlights the critical features of the magnetic detection system used to quantify the paramagnetic particles and a novel frequency-locked loop-based magnetometer is presented. A study of paramagnetic particle enhanced lysis demonstrates that the technique is more than twice as efficient at releasing intracellular protein as ultrasonic lysis alone. Results are presented for measurements of intracellular prostate specific antigen in an LNCAP cell line. This model was selected to demonstrate the rapidity and efficiency of intracellular protein quantification. It was shown that, on average, LNCAP cells contained 0.43 fg of prostate specific antigen. This system promises an attractive solution for applications that require a rapid determination of intracellular proteins.