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Incorporating nanotechnology into fluorescent imaging and magnetic resonance imaging (MRI) has shown
promising potentials for accurate diagnosis of cancer at earlier stage than the conventional imaging modalities. Molecular
imaging (MI) aims to quantitatively characterize, visualize, and measure the biological processes or living cells at molecular and genetic levels. MI modalities have been exploited in different applications including noninvasive determination
and visualization of diseased tissues, cell trafficking visualization, early detection, treatment response monitoring, and in
vivo visualization of living cells. High affinity molecular probe and imaging modality to detect the probe are the two main
requirements of MI. Recent advances in nanotechnology and allied modalities, have facilitated the use of nanoparticles
(NPs) as MI probes. Within the extensive group of NPs, fluorescent NPs play a prominent role in optical molecular imaging. The fluorescent NPs used in molecular and cellular imaging can be categorized into three main groups including
quantum dots (QDs), upconversion, and dye-doped NPs. Fluorescent NPs have great potentials in targeted theranostics including cancer imaging, immunoassay based cells, proteins and bacteria detections, imaging-guided surgery and therapy.
Fluorescent NPs have shown promising potentials for drug and gene delivery, detection of the chromosomal abnormalities, labeling of DNA, and visualizing DNA replication dynamics. Multifunctional NPs have been successfully used in a
single theranostic modality integrating diagnosis and therapy. The unique characteristics of multifunctional NPs make
them potential theranostic agents that can be utilized concurrently for diagnosis and therapy. This review provides state of
the art of the nanotechnological applications for early cancer diagnosis focusing on fluorescent NPs, their synthesis methods and perspectives in clinical theranostics.