Applications of probiotic bacteria and nanoparticles (NPs) as therapeutic agents have great importance. This study demonstrates a combinatorial approach of both the probiotic Lactobacillus spp. (Lactobacillus fermentum and Lactobacillus plantarum) with fluorescent cadmium sulfide (CdS) NPs as therapeutic agents to target MCF-7 cancer cells (human breast cancer cells). In this study, facultative anaerobic Lactobacillus was successfully used as a vehicle to transport NPs into MCF-7 cancer cells. The cell viability assay and invasion study along with confocal and field emission scanning electron microscopy (FESEM) confirmed the release of payload (CdS NPs) into cytoplasm without any external stimuli. The biosynthesized CdS NPs of ∼22 nm were characterized by FESEM, transmission electron microscopy (TEM), atomic force microscopy (AFM), and fluorescence spectroscopy. The bacteria-NPs (microbots) interaction was investigated by growth curve studies, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), FESEM, energy dispersive X-ray spectroscopy (EDX), and fluorescence and confocal microscopy. This alternative approach showed an approved and inexpensive delivering mode of specific functional cargos or therapeutic agents into the cancer cells.
Keywords: Cadmium sulfide; Fluorescence; Lactobacillus; MCF-7 cells; Microbots; Nanoparticles.