A novel functionaliztion of gold nanorods (GNRs) intracellular delivery system was prepared via electrostatically layer-by-layer assemblying, in which multilayer polyelectrolyte-coated GNRs were used as vector and antisense oligodeoxynucleotides (ASODNs) as therapeutic gene. The as-prepared positively charged GNRs were firstly modified with two successive polyelectrolyte layers of the negatively charged poly(sodium-4-styrenesulfonate) (PSS) and positively charged polyenthylenimine (PEI) in order to greatly improve the biocompatibility of these cetyltrimethylammonium bromide(CTAB)-coated GNRs and facilitate further biofunctionalization. The multilayered polyelectrolyte functionalized GNRs were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM) and MTT assay. The polyelectrolytes-coated GNRs were then used as vector for ASODNs. Electrochemical impedance spectroscopy(EIS) was employed to confirm the formation of the GNRs-ASODNs conjugates through electrostatic interaction. Furthermore, cellular uptake and delivery efficiency of the GNRs-ASODNs conjugates as well as cellular apoptosis induced by the ASODNs transfected with gold nanorods were investigated by confocal microscopy and flow cytometry, exhibiting efficient intracellular delivery and improved antitumor activity of ASODNs by the polyelectrolytes-coated GNRs carriers.
The uniform-sized manganese oxide nanoparticles (the oleic-capped MnO NPs) were synthesized by the thermal decomposition of Mn-oleate complex and were transferred into water with the help of cationic surfactant of cetyltrimethyl ammonium bromide (CTAB), then the poly(vinylpyrrolidone) (PVP) membrane was further coated on to them with the aid of anionic dispersant of poly(styrenesulfonate) (PSS) by layer-by-layer electrostatic assembly to render them water soluble and biocompatible. They were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and MTT assay. In vitro cellular uptake test revealed the MnO@PVP NPs were low cytotoxic, biocompatible and could be used as a T,-positive contrast agent for passive targeting magnetic resonance imaging (MRI). Interestingly, signal enhancement in cerebral spinal fluid (CSF) spaces in vivo experiment suggested that the MnO@PVP NPs can pass through the blood brain barrier (BBB). These results show that MnO@PVP NPs are good candidates as MRI contrast agents with the lack of cytotoxicity and have great potential applications in magnetic nano-device and biomagnetic field.
Antisense oligodeoxynucleotides (ASODNs) can bind to some specific RNA of survivin can prevent the mRNA translation at the genetic level, which will inhibit survivin expression and make the cancer cells apoptosis. However, the ASODNs-based therapies are hampered by their instability to cellular nuclease and their weak intracellular penetration. Here we reported a calcium phosphate (CP)-based carrier to achieve efficient delivery of ASODNs into cells. In this study, we used a facile microemulsion approach to prepare spherical and porous ASODNs-CP nanoparticles (ASODNS-CPNPs) with the size of 50-70 nm in diameter, and their structure, morphology and composition were characterized by TEM, XRD, FTIR, ICP and DLS, UV-Vis spectroscopy and agarose gel electrophoresis. The results indicated that the nanoparticles have a high ASODNs loading capacity. Furthermore, cellular uptake and delivery efficiency of the ASODNS-CPNPs, as well as cellular apoptosis induced by the ASODNs doping into the calcium phosphate nanoparticles, were investigated by confocal laser scanning microscopy, biological TEM, flow cytometry, and MTT assay. Efficient intracellular delivery of the nanoparticles was observed. All these results suggested that the prepared calcium phosphate nanoparticles could be used as a promising biocarrier for delivery of ASODNs.
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