Nanoplasmonic biosensor for cancer diagnosis: Design and fabrication

Abstract

In this study, gold nanoplasmonic biosensors using localized surface plasmon resonance (LSPR) were fabricated for the diagnosis of cancer. We optimized the structures of the gold nanodot array (GNA) via the experiments for the optical characteristics. In addition, the nanoimprint lithography was employed for realizing nanoplasmonic structures, which is a more efficient technique for mass production than nanolithography such as electron beam lithography (EBL) or focused ion beam (FIB) lithography that is a quite intricate, time-consuming and expensive process. After the UV nanoimprinting process using a film stamp and metal films were deposited using an electron-beam evaporator, followed by the lift-off step. Consequently, the nanoplasmonic MNA was realized on 5-inch glass wafer and the pitch, diameter and height of MNA were 300nm, 150 nm and 20 nm, respectively. The wavelength of nanoplasmonic resonance peak represented from the MNA sensors was about 740nm under aqueous ambient. The capture antibodies of the lung and the pancreas cancer marker, respectively, were immobilized on the surfaces of MNA sensor. Using a compact fiber-optic spectrometer and a reflection optical probe, we were able to confirm the binding of cancer markers with their antibodies due to the immunoreactions between each cancer marker and its corresponding antibody on the sensor surfaces. The amount of the cancer markers in serum were analyzed through the observation of nanoplasmonic resonance wavelength-shift on the reflection spectra. To amplify a sensitivity of detection demonstrated by the nanoplasmonic resonance peak shift, we applied enzyme-precipitation reaction on the surface of MNA biosensor. The enzyme-catalyzed precipitation method in the GNA biosensor could be extended to detect other clinical biomarkers at extremely low concentrations in actual clinical samples.