In vitro evaluation of cobalt zinc ferrite nanoparticles for the SS-OCT imaging and simultaneous drug delivery in colorectal cancer

Swept-source optical coherence tomography (SS-OCT), a non-invasive imaging technique based on the backscattering property of biological tissues, offers an improved signal-to-noise ratio, higher imaging speed, and better resolution than the conventional spectral domain OCT. SS-OCT, however, provides limited penetration ability and contrast, which can be partially overcome by exploiting nanoparticles (NPs) as exogenous contrast agents to improve image contrast. Moreover, the utilization of NPs capable of being magnetically targeted to deep tumor regions for simultaneous drug delivery and imaging has also gained tremendous attention over the past few years. Thus, in this work, the feasibility of cobalt zinc ferrite NPs (CZFNPs) as an SS-OCT contrast agent was explored. In addition, due to the ferromagnetic nature of CZFNPs, these NPs were also exploited for the magnetically targeted simultaneous (along with imaging) delivery of 5-Fluorouracil in colorectal cancer tissue phantoms. To validate the imaging ability of CZFNPs, scattering coefficient and contrast-to-noise ratio calculations were done at different time exposures, while their drug delivery/anti-cancer potential was assessed using cell viability studies. Post analysis, a substantial increase in contrast and scattering coefficient was observed with time. Additionally, a significant site-specific killing of cancer cells was also achieved in comparison to the free drug.