Acoustic Wave Biosensor for the Detection of the Breast Cancer Metastasis Biomarker Protein PTHrP

This manuscript illustrates the three stage development of a biosensor capable of detecting a breast cancer metastasis biomarker protein. In the first stage of development, a new reducing agent was discovered for the formation of antibody fragment antigen-binding (Fab’) units. This reducing agent, dithiobutylamine (DTBA), was found to be 213 times more efficient than the previously accepted leading reducing agent, dithiothreitol (DTT), at cleaving antibody F(ab)2 fragments. The second stage of development studied the anti-fouling properties of Fab’ fragments on various homogeneous and mixed alkylsilane monolayers. Immobilized Fab’ fragments were determined to impart anti-fouling properties onto these surfaces, making them ideal for use in biosensors. The last stage of development compared whole antibody and Fab’ fragment-based biosensors for the detection of the cancer metastasis protein in buffer, with the whole antibody-based biosensor yielding the lowest limit of detection of 61 ng/mL.M.Sc