Near infrared receptor-targeted nanoprobes for early diagnosis of cancers.

The success of detecting cancer at early stages relies greatly on the sensitivity and specificity of in vivo molecular imaging. Optical imaging with near infrared (NIR) luminescent molecular nanoprobes currently attracts much attention because of many advantages of this imaging modality. It provides real time imaging with relatively inexpensive cost, produces images with high sensitivity and spatial resolution, and avoids exposure to ionizing irradiation. Raman spectroscopy/microscopy imaging with surface enhanced Raman scattering (SERS) nanoparticles allows scientists to detect biological events in living cells or organisms in real time and with high sensitivity. The photoacoustic imaging has emerged as a hybrid of optical and ultrasound imaging for sensitive and quantitative tumor detection. Given the recent advances in nanoscience and biomedicine, receptor-targeted NIR nanoprobes promise to improve the cancer early detection with relatively high sensitivity and specificity. We summarize various targeted NIR nanoprobes and their potential applications in cancer targeting and in vivo imaging and discuss the potential of multimodality imaging of NIR nanoprobes. With ongoing efforts to enhance their targeting ability and endow more functions, NIR nanoprobes hold great promise for clinical translation.