Nanomaterials for early detection of cancer biomarker with special emphasis on gold nanoparticles in immunoassays/sensors.

At the onset of cancer a selective protein or gene based biomarker gets elevated or modified in body fluids or tissues. Early diagnosis of these markers can greatly improve the survival rate or facilitate effective treatment with different modalities. Though the sophisticated imaging technologies like Magnetic Resonance Imaging, Positron Emission Tomography and Computed Tomography have the impact of nanotechnology on their improved performance, they are however unsuitable for early detection of cancer biomarkers or their quantification. Other approaches for cancer diagnosis based on cell morphology and microscopy (biopsies) are too not conclusive for early diagnosis of cancer. The only hope for early diagnosis of cancer in near future is by the detection of cancer biomarkers using immunoassays/sensors that are reformed by Nanotechnology. Attractive properties of nanoparticles have miraculously lifted up the design, fabrication, sensitivity and multiplexing of these immunoassays/sensors in biomarker detection. With this aspect we have explored the recent advancements in immunosensing techniques that were developed exploiting the unique properties of gold nanoparticles. We have also discussed the possible future trends with respect to gold nanoparticle-coupled microfluidic sensors; paper based analytical devices and the single-molecule biosensing.