Breast cancer imaging with fluoresce in isothiocyanate-modified gold nanoparticles in-vitro and in-vivo

Objective: To prepare fluorescein isothiocyanate (FITC)-modified gold nanoparticles (FITC-Au NPs) and conduct in-vitro and in-vivo breast cancer imaging studies with them. Methods: Nanosizer and transmission electron microscopy were used to characterize the diameter and morphology of FITC-Au NPs and their stability; UV spectrophotometer and fluorescence spectrometer were used to detect the UV and fluorescence spectra of FITC-Au NPs; Cell counting kit (CCK-8) method was used to detect the in-vitro cytotoxicity of Au NPs and FITC-Au NPs in breast cancer 4T1 cells; Confocal microscopy was used to observe FITC-Au NPs uptaken by cells; A small living animals fluorescence imaging system, after tail intravenous injection, was used to observe the distribution of FITC-Au NPs in tumor-bearing mice and the concentration of NPs in the tumor region. Results: The average diameter of Au NPs and FITC-Au NPs were 43 nm and 52.6 nm, respectively. FITC-Au NPs were globular nanoparticles. After standing for 28 days, NPs and FITC-Au NPs showed no change in diameter. The UV spectra of FITC-Au NPs showed a characteristic absorption peak of FITC and Au NP, and the maximal emission peak of FITC-Au NP (520 nm) was excited by 488 nm laser. No significant cytotoxicity was found for cells treated by 0-150 ug/ml of Au NPs and FITC-Au NPs for 12 or 24 hours. Compared with free FITC, FITC-Au NP were uptaken by cells remarkably. In addition, results of in-vivo study indicated that FITC-Au NPs passively targeted the tumor region efficiently. Conclusion: FITC-Au NPs can be applied as the contrast agent of in-vivo and in-vitro breast cancer fluorescence imaging, providing a molecular imaging basis for the medical diagnosis of breast cancer.