Cell membrane-coated gold nanoparticles for apoptosis imaging in living cells based on fluorescent determination.

A nanoprobe was developed to achieve apoptosis detection by cell membrane-functionalized gold nanoparticles (AuNP-pep@Mem). The fluorescence of the fluorescein isothiocyanate isomer I (FITC)-labeled caspase-3 substrates was quenched by the attachment to AuNPs. The fluorescence signal was recovered via the cleavage of caspase-3 under apoptotic conditions. It exhibited a low detection limit of 1.3 pg·mL-1 with a linear range from 3.2 to 100 pg·mL-1 for caspase-3 detection with excitation wavelength of 490 nm. After wrapped by the cell membrane, the nanoprobe was effectively delivered into cells with high cell permeability. AuNP-pep@Mem nanoprobe provided signal enhancement of 1.8 times in living cells compared to non-membrane-coated nanoparticles (AuNP-pep). In combination with its excellent stability, low LOD and good specificity, the AuNP-pep@Mem probe can be an ideal probe for fluorescence imaging of apoptosis. Graphical abstractSchematic representation of fluorescent determination for apoptosis in living cells based on cell membrane-coated gold nanoparticls.