Confinement of AuAg NCs in a Pomegranate-Type Silica Architecture for Improved Copper Ion Sensing and Imaging

Metal nanoclusters (NCs) have been in focus received attention due to their superior optical properties, whereas their biomedical applications are limited by the relatively low quantum yield and poor cellular uptaking behaviors. In the present study, a pomegranate-type architecture with densely packed AuAg NCs is constructed, where the aminoterminated dendritic silica spheres (dNSiO₂) with ultralarge central-radial pore channels act as an efficient absorbent host for self-assembling of AuAg NCs. The spatial confinement of AuAg NCs within the pomegranate-type silica architecture not only avoids the time-tedious purification procedure in metal NCs fabrication but also offer significant improvement of the photoluminescence performance of AuAg NCs, i.e., the quantum yield (17.0%) is nearly doubled when compared to that of free AuAg NCs. The presence of Cu²⁺ induces efficient quenching of the photoluminescence of obtained dNSiO₂-AuAg NCs, achieving the sensitive detection of Cu²⁺ with a detection limit of 0.060 μM. Moreover, the pomegranate-type silica architecture serves itself as an excellent nanocarrier to deliver AuAg NCs into living cells, making dNSiO₂-AuAg NCs an efficient probe for intracellular Cu²⁺ sensing and imaging.