Polyamine-Modified Gold Nanoparticles Readily Adsorb on Cell Membranes for Bioimaging.

The surface modification of nanoparticles (NPs) can enhance cellular and intracellular targeting. A new type of polyamine-modified gold NPs (AuNPs) are designed and synthesized, which can be selectively absorbed onto the cell membrane. AuNPs with an average diameter of 4.0 nm were prepared and modified with polyamine (R-4C) through amidation. In order to detect the distribution of NPs within cells by fluorescence imaging, AuNP@MPA-R-4C was functionalized with fluorescein isothiocyanate (FITC). The fluorescence-labled NPs AuNP@MPA-R-4C-FITC demonstrated minimal cytotoxicity in several cell lines. Both confocal laser scanning microscopy and transmission electron microscopy demonstrated that AuNP@MPA-R-4C-FITC was distributed on the cell membrane. Compared with the free organic dye, the modified AuNPs showed significantly increased accumulation on the cell membrane after treatment for only 10 min. These results suggested that AuNP@MPA-R-4C-FITC can be used as a bioprobe targeting the cell membrane for various biological applications.

The Apoptosis Effect on Liver Cancer Cells of Gold Nanoparticles Modified with Lithocholic Acid.

Functionalized gold nanoparticles (AuNPs) have widely applied in many fields, due to their good biocompatibility, a long drug half-life, and their bioactivity is related to their size and the modified ligands on their surface. Here, we synthesized the AuNPs capped with ligands that possess polyethylene glycol (PEG) and lithocholic acid (LCA) linked by carboxyl groups (AuNP@MPA-PEG-LCA). Our cytotoxicity results indicated that AuNP@MPA-PEG-LCA have better cell selectivity; in other words, it could inhibit the growth of multiple liver cancer cells more effectively than other cancer cells and normal cells. Apoptosis plays a role in AuNP@MPA-PEG-LCA inhibition cell proliferation, which was convincingly proved by some apoptotic index experiments, such as nuclear staining, annexin V-FITC, mitochondrial membrane potential (MMP) analysis, and AO/EB staining experiments. The most potent AuNP@MPA-PEG-LCA were confirmed to efficiently induce apoptosis through a reactive oxygen species (ROS) mediating mitochondrial dysfunction. And AuNP@MPA-PEG-LCA could be more effective in promoting programmed cell death of liver cancer cells.

The delivery of doxorubicin of multifunctional ß-cyclodextrin-modified CdSe/ZnS quantum dots for bioactivity and nano-probing.

The modified quantum dots (QDs) have been used in intracellular probing and drug delivery because of their special chemical and physical properties. In this paper, two ß-cyclodextrin (ß-CD)-modified CdSe/ZnS QDs with strong optical emission properties were synthesized as drug carriers to induce apoptosis. The positively charged l-Arginine (l-Arg) and neutral l-Tryptophan (l-Trp) were selected as ligands to compare the effect of charge on bioactivity of QDs nanoparticles. The in vitro assays revealed that these modified QDs showed good Dox carrier ability and significantly high inhibition rate to cancer cells. Especially, the more positively charged ß-CD-l-Arg-polyamine-coated CdSe/ZnS QDs could effectively deliver the doxorubicin (Dox) into cells and exhibit excellent cell selectivity in cancer versus normal cells. The Dox-loaded QDs could enter intracellular, which showed that the Dox can efficiently go through the membranes at the existence of ß-CD. Several lines of evidence suggest that the Dox-loaded QDs can efficiently induce apoptosis likely related to the production of ROS. We expect that the modified QDs can enhance the amount of hydrophobic antitumor drugs in cells and can also be used as fluorescent imaging agents.

The Research and Applications of Quantum Dots as Nano-Carriers for Targeted Drug Delivery and Cancer Therapy.

Quantum dots (QDs), nano-carriers for drugs, can help realize the targeting of drugs, and improve the bioavailability of drugs in biological fields. And, a QD nano-carrier system for drugs has the potential to realize early detection, monitoring, and localized treatments of specific disease sites. In addition, QD nano-carrier systems for drugs can improve stability of drugs, lengthen circulation time in vivo, enhance targeted absorption, and improve the distribution and metabolism process of drugs in organization. So, the development of QD nano-carriers for drugs has become a hotspot in the fields of nano-drug research in recent years. In this paper, we review the advantages and applications of the QD nano-carriers for drugs in biological fields.