BSA-AuNCs emit red light that offer improved tissue penetration depth and negligible fluorescence background.
FA can interact with BSA, leading to fluorescence intensity quenching of BSA-AuNCs.
FA@BSA-AuNCs nanocomposite as a turn-on probe can be used for imaging of FR overexpressed tumor cells.
The probe with “off-on” mechanism can avoid false positive results.