Quantum dots loaded nanogels for low cytotoxicity, pH-sensitive fluorescence, cell imaging and drug delivery

• The quantum dots loaded nanogels were formed with a simple method.
• The cytotoxicity of the quantum dots loaded nanogels was diminished comparing with free quantum dots.
• The quantum dots loaded nanogels may be used as fluorescence probes and drug carriers.

Nanogels (NGs) with drug tracking and delivery possess promising usage in clinical treatment. In this study, an available, low toxic and facile approach was developed to synthesize CdTe quantum dots loaded nanogels (QDs-NGs). The QDs-NGs retained the intrinsic pH sensitivity of the QDs with regard to the fluorescence intensity. The QDs-NGs were easily internalized by the cells as fluorescence probes, and acted as carriers for delivering methotrexate (MTX). The cellular uptake indicated that the QDs-NGs can protect QDs from decomposition in cytoplasm and retain the native fluorescence intensity. MTT assay demonstrated that the QDs-NGs greatly decreased the cytotoxicity of the QDs. The MTX loaded QDs-NGs exhibited slow release property in PBS buffer. Moreover, the MTX loaded QDs-NGs distinctly enhanced the availability of drug. The QDs-NGs are potential nanocarriers for the cell imaging and drug delivery.