Sodium alginate passivated CuInS2/ZnS QDs encapsulated in the mesoporous channels of amine modified SBA 15 with excellent photostability and biocompatibility.

ABSTRACT

We herein report the synthesis of CuInS2/ZnS (CIS/ZnS) quantum dots (QDs) via a greener method followed by sodium alginate (SA) passivation and encapsulation into mesoporous channels of amine modified silica (SBA15-NH2) for improved photostability and biocompatibility. The as-synthesized CIS/ZnS QDs exhibited near infrared emission even after SA passivation and silica encapsulation. Transmission electron microscopy (TEM) and Small angle X-ray diffraction (XRD) revealed the mesoporous nature of the SBA-15 remained stable after loading with the SA-CIS/ZnS QDs. The effective encapsulation of SA-CIS/ZnS QDs inside the pores of SBA15-NH2 matrix was confirmed by Brunauer-Emmett-Teller (BET) pore volume analysis while the interaction between the QDs and SBA15-NH2 was confirmed using Fourier transform infrared (FTIR) spectroscopy. The photostability of the QDs was greatly enhanced after these modifications. The resultant SA-CIS/ZnS-SBA15-NH2 (QDs-silica) composite possessed remarkable biocompatibility towards lung cancer (A549) and kidney (HEK 293) cell lines making it a versatile material for theranostic applications.