Investigation by CARS microscopy of squalene and boron nitride as a precursor material for drug delivery carrier

[Display omitted] •CARS technique was applied to visualize squalene and boron nitride materials as a promising precursors building drug carriers for drug delivery system. It was demonstrated that chemical selectivity and high spatial resolution of CARS microscopy is powerful tool to image nano-size particles made of such materials. Such technique is a label-free imaging, enabling visualization of such particles without staining. Recently organic squalene and inorganic boron nitride have been considered as precursor materials for drug delivery systems. Drug carriers introduced in the organism need to be monitored to control the drug release within the body. Squalene or boron nitride-based prodrugs usually form nanoparticles or micelles which can be monitored by optical microscopy utilizing fluorescence light originating from drug molecules or dye molecules intentionally introduced for imaging purposes. Coherent anti-stokes Raman scattering (CARS) microscopy is an alternative approach to visualize such particles without labeling. This label-free imaging, based on molecular vibrations is a promising technique in cases where the dye staining cannot be used because of its toxicity or bio-incompatibility. In this paper, we present the CARS microspectroscopy study of squalene and boron nitride materials providing their spectra and images within the fingerprint region.