Theranostic Applications of Functional Nanomaterials Using Microscopic and Spectroscopic Techniques

Theranostics encompasses the diagnostic and therapeutic capabilities concurrently offered by nanomaterials through imaging and spectral techniques. Several nanomaterials have been functionalized for specialized theranostic applications, including metal and metal-oxide nanoparticles, carbon-based nanomaterials, polymeric nanomaterials, lipid-based nanoparticles, quantum dots, and biomimetic nanomaterials. Some of the functionalization of these nanomaterials are steered to develop superior properties that are desirable for theranostic applications, including biocompatibility, nontoxicity, hydrophilicity, lipophilicity, and colloidal stability. This functionalization assists the nanomaterials in transferring and diffusing across various biological barriers, such as blood–brain barrier, extracellular matrix, mucous, and cell walls, in terms of acting as effective imaging, spectral and theranostic agents. Some of the innovative imaging techniques like in vivo and in vitro fluorescence microscopy, electron microscopy, 2D/3D-confocal microscopy, 3D-two-photon laser scanning microscopy, and spectral techniques like inductively coupled mass spectrometry (ICP-MS), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, impedance spectroscopy and recent hybrid techniques like hyperspectral imaging (HSI) and UV-Vis-NIR spectroscopy have been successfully developed as promising and feasible theranostic applications. By applying these cutting-edge functionalized nanomaterials, early diagnosis and prompt delivery of medicine can be made possible, allowing hospitals to include hybrid microscopic and spectral imaging modalities into routine patient care.