Figure 1.
Quantum dot-loaded microcapsule characterization.
(A) Schematic representation of the formation of QD-loaded microcapsules. (B) Histogram of the size distribution of QDMCs. (C) Brightfield and (D) fluorescence images of the QDMCs, showing that the microcapsules are monodisperse and contain QDs (ex/em 380/545).
Figure 2.
Flowchart of the protocol used for testing the cellular response (cytotoxicity and morphology) of human dermal fibroblasts (HDF) to free quantum dots (QD) and quantum dot loaded microcapsules (QDMC). Cultured cells were exposed to either QD or QDMC for all experiments. CdCl2 was used in some experiments as a positive control. Cytotoxicity, including % dead, metabolism, and apoptosis, were determined over a dose-response, while cellular morphology and uptake were determined over a time course.
Table 1.
QD and QDMC characterization table.
Figure 3.
Cytotoxicity was measured at A) 12 hrs, B) 24 hrs, and C) 48 hrs via fluorescence intensity of reduced resazurin. HDF cells at all time points were either exposed to 0.05–50 nM QDs or microencapsulated QDMCs, 20 or 120 µM cadmium chloride positive control, or unexposed. * p-val<0.05, ** p-val<0.001. Note: the QDMC concentrations refer to the total concentration of QDs contained in the microcapsules.
Figure 4.
QD association and cellular morphology.
(A) QD accumulation in HDF mitochondria (Confocal, 60×, Zeiss). (B) The number of QD aggregates accumulating in HDF increases over time. Fluorescence images of cells dosed with QDs at the (C) 12 hr and (D) 48 hr time points. Images of cells dosed with QDMCs (at an equivalent amount of Cd+2 ions relative to QDs) at the (E) 12 hr and (F) 48 hr time points. Microcapsules are resting on top of cells, but do not enter cells. Cells dosed with an equivalent Cd atom concentration of the QD-loaded microcapsules displayed no evidence of particle uptake and remained viable with no sign of deterioration through the 48 hr time point.