Ecofriendly Multiphase Aqueous Colloidal Based on Carboxymethylcellulose Nanoconjugates with Luminescence Properties for Potential Bioimaging Cancer Cells

Quantum dots (QD) or semiconductor nanoparticles are within the most researched nanomaterials currently. Their attractive optical, electronic and chemical properties can be adjusted by varying composition, size, and synthesis parameters. This tunability pushes these nanocrystals into different types of applications such as biomedical and environmental ones. One of the concerns about their use regards the inherent toxicity related to the most efficient emission QD based on heavy metals. In this context, we report the synthesis of eco-friendly Ag-In-S (AIS) and Zn-Ag-In-S (ZAIS) QD conjugated with a biodegradable polymer, carboxymethylcellulose (CMC). Colloidal AIS were synthesized using an eco-friendly aqueous route at room temperature. Co-precipitation process was controlled via CMC with two degrees of substitution (DS) and under different pH conditions. In order to improve the as-prepared AIS' optical properties, ZnS was deposited over the nanocrystals with further annealing process, creating a core/shell alloyed nanostructure. The obtained QD were extensively characterized considering their optical, physicochemical and morphological features. Results demonstrated the presence of fairly monodispersed photoluminescent nanoparticles with average size of 3.0 nm for AIS QD and 4.3 nm for ZAIS QD. Moreover, modifying the synthesis parameters, it was possible to tune and improve the emission of the fluorescent nanoparticles (lambda(em) = 500 to 900 nm). Diffraction patterns suggested the formation of solid solutions of AIS and its correspondent binary compounds. Furthermore, cellular uptake assays demonstrated a more rapid internalization of fluorescent AIS and ZAIS nanoconjugates by cancer cells when compared to normal cells. These luminescent materials showed the potential of use in a wide range of applications, such as bioimaging of cancer cells.