In this work, we have developed multiple-armed DNA tetrahedral nanostructures (TDNs) for dual-modality in vivo imaging using near-infrared (NIR) fluorescence and single-photon emission computed tomography (SPECT). We found that the presence of arm strands in TDNs remarkably enhanced their in vitro stability, allowing them to stay intact for at least 12 h in serum. By using NIR fluorescence imaging, we evaluated in mice the pharmacokinetics of TDNs, which exhibited distinctly different in vivo biodistribution patterns compared with those of double-stranded (ds)DNA. We also noticed that TDNs had twofold longer circulation time in the blood system than that of dsDNA. With the use of multiple-armed TDNs, we could precisely anchor an exact number of functional groups including tumor-targeting folic acid (FA), NIR emitter Dylight 755, and radioactive isotope 99mTc on prescribed positions of TDNs, which showed the capability of targeted imaging ability in cancer cells. Furthermore, we realized noninvasive tumor-targeting imaging in tumor-bearing mice by using both NIR and SPECT modalities.Keywords: dual-modality imaging; near-infrared fluorescence; single-photon emission computed tomography; tetrahedral DNA nanostructures; tumor targeting

We present a bioprobe for synchrotron X-ray fluorescence imaging based on dendrimer–folate–copper conjugates. The metal nanoclusters within a dendrimer exhibit excellent FR-targeting properties in KB cells. It could be used as a new multifunction bioprobe for synchrotron X-ray fluorescence mapping.

Dexamethasone (DEX) is a well-known anti-inflammatory drug, whose widespread clinical use is nevertheless restricted by its serious side effects. By conjugation of DEX with C60, we found that this nanomedicine retained the anti-inflammatory activity of DEX while reducing side effects in the animal model. In mouse thymocytes, the CCK-8 assay showed that the cytotoxicity of DEX–C60 was significantly lower than that of free DEX. Flow cytometric studies revealed that incubation with DEX–C60 induced much less apoptotic thymocytes. Interestingly, such reduced cytotoxicity and apoptosis were not observed when equal moles of free C60 and free DEX were coincubated with thymocytes, suggesting that the conjugation alters the signal pathway of DEX. Indeed, we found that the binding of DEX–C60 and a glucocorticoid receptor (GR) was partially blocked in the thymocytes, which resulted in down-regulation of several apoptosis-related genes. These findings help understand the mechanism of beneficial effects of this new nanomedicine, DEX–C60, and promote its clinical applications.Keywords: apoptosis; C60; dexamethasone; glucocorticoid receptor; thymocytes;

Curcumin has anti-proliferative and pro-apototic properties against a variety of cancer cells in vitro. Unfortunately, the water-insolubility and instability leads to its low bioavailability in vivo tests. Here, we report a general approach to using poly(amidoamine) dendrimer with acetyl terminal groups to encapsulate curcumin(G5-Ac/Cur) for drug delivery to cancer cells. The solubility, release kinetics, anticancer activity, and apoptotic-related protein expression (Bax and Bcl-2) were investigated in detail. Comparing with curcumin, the water-solubility value of G5-Ac/Cur increased 200-fold, and the release of curcumin from the complexes was in a sustained manner. G5-Ac/Cur showed higher anti-proliferative activity against A549 cell lines and had the better effect on the generation of intracellular reactive oxygen species, the mitochondrial membrane potential and cell apoptosis. Furthermore, the ratio of Bax/Bcl-2 was higher in samples treated with G5-Ac/Cur. The results indicated that the G5-Ac drug delivery system could improve the solubility and anti-cancer effect of curcumin.

We present a bioprobe for synchrotron X-ray fluorescence imaging based on dendrimer–folate–copper conjugates. The metal nanoclusters within a dendrimer exhibit excellent FR-targeting properties in KB cells. It could be used as a new multifunction bioprobe for synchrotron X-ray fluorescence mapping.