Objective: The label free ultrasmall fluorescent ferrite clusters have been engineered in a
controlled fashion which was stabilized by serum protein and functionalized by folic acid for the application
of targeted multimodal optical and Magnetic Resonance (MR) cancer imaging.
Methods: The ultra-small manganese ferrite nanoclusters (PMNCs) with a diameter of 4 nm have a
commendable effect on the longitudinal (T1) and transverse (T2) relaxation in MR imaging that was
evident from the phantom and animal MRI.
Results: The calculated longitudinal molar relaxivity of nanoclusters was found to be 6.9 ± 0.10 mM-1
S-1 which was exactly 2.22 times better than the conventional Gd-DOTA and their 4.01 ratio of the
transverse (r2) and longitudinal (r1) relaxivities made them a potential candidate for both T1 and T2
contrast agents in MRI. In addition, the fluorescence-based small animal imaging showed folic acid
driven accumulated fluorescent signal at the tumour site to conclude the capacity of PMNCs for targeted
fluorescence imaging of cancer diagnosis.
Conclusion: The cytotoxicity assay and histopathology studies were the evidence for their safe biodistribution
in animal systems. Furthermore, the protein encapsulated clusters have the ability to deliver
the anticancer drug Methotrexate (MTX) to the cancer tissues with a sustained manner. Therefore, one
can conclude the remarkable efficacy of architect nanoclusters for theragnosis.