Figure 1.
Construction of the S2.2-spacer aptamer and PTX-Apt-NPs.
(A) Structure of MUC1 aptamer S2.2-spacer. The S2.2-spacer is made of the MUC1 aptamer S2.2 (as the targeting agent) and a designed sequence of single strand DNA (as the linking spacer). (B) Preparation procedure for PTX-Apt-NP using the emulsion/evaporation method.
Figure 2.
FCM analysis of MCF-7 and HepG2 cells incubated with random DNA, MUC1 aptamer S2.2, or S2.2-spacer.
(A) Histograms of FCM analysis. FITC-labeled random DNA, S2.2, or S2.2-spacer was incubated separately with MCF-7 (left) and HepG2 (right) cells. (B) The mean fluorescent intensity of MCF-7 and HepG2 cells incubated with random DNA and different aptamers.
Figure 3.
Analysis of aptamer conjugation to microparticles or nanoparticles.
The PLGA microparticles (MPs) or nanoparticles (NPs) reacted with aptamers in the absence (-EDC&NHS) or presence (+EDC&NHS) of the catalysts. (A) Histograms of FCM analysis of MP reacted with FITC-labeled aptamers in the absence (-EDC&NHS, left) or presence (+EDC&NHS, right) of the catalysts. Plain microparticles that had not reacted with aptamers were used as control. (B) UV absorption of DNA at 260 nm (n = 3) on the particles that underwent conjugation process with aptamers. The control group (NPs) indicates plain nanoparticles that have not reacted with DNA aptamers.
Figure 4.
In vitro drug release profile of the PTX encapsulated Apt-NPs.
The experiment was conducted in phosphate buffer saline (PBS, pH 7.4) containing 0.5% (w/v) poloxamer using the membrane diffusion technique, (n = 3).
Figure 5.
FCM analysis of cellular uptake of Apt-NPs and NPs by MCF-7 (left) and HepG2 cells (right).
The cells were incubated with FITC encapsulated Apt-NPs or NPs at 50 µg/ml for 2 hours before subject to analysis.
Figure 6.
Confocal fluorescent scanning microscopy images detecting cellular uptake of Apt-NPs (top row) or NPs (bottom row) in MCF-7 cells.
Green fluorescent FITC was encapsulated in Apt-NPs and NPs. The nuclei were stained blue with DAPI. The right column showed the merged images of the FITC and the DAPI channels. MCF-7 cells were exposed to FITC-encapsulated Apt-NPs or NPs at 100 µg/ml for 2 hours.
Figure 7.
Cytotoxicity assays of MCF-7 (Left) and HepG2 cells (Right) treated for 4 hours with plain nanoparticles (NP), free paclitaxel (PTX), PTX-loaded NPs (PTX-NP), PTX-loaded NPs conjugated to random DNA (PTX-R-NP), or PTX-loaded NPs conjugated to MUC1 aptamer (PTX-Apt-NP).
The cells were subsequently washed and incubated in culture media for a total of 48 hours, before cell viability in each group was assessed with a standard MTS assay (n = 6, mean ± SD).