Abstract

Timely diagnosis of critical diseases, such as cancer, may help in its effective management and better survival. Several techniques like magnetic resonance imaging (MRI), computed tomography scan (CT scan), positron emission tomography (PET), photoacoustic imaging (PAI), etc. are already being used successfully, but sometimes their high cost, spatial resolution, sensitivity, and specificity (associated with the use of contrast agent) have been questionable. The distinction between benign and malignant tumours in their early stages is also a critical issue with such methods. But the use of nano-carriers for diagnostic and theranostics purposes has opened newer dimensions and provided a better understanding and visualization of the pathophysiological condition in a specific disease. There are different nanotechnologybased systems like bio-labels containing nanoparticles, nanotechnology-based microarrays, nano-bio sensors, and nanoscale optics that can be used in molecular diagnostics. Several nano-carriers, especially after their surface functionalization, are also on the floor, showing their importance in the medical diagnosis of different diseases. The current chapter deals with the importance and significance of such different nano-carriers in the development of diagnostics and theranostics.