Co-loading Of As-miR-21and Doxorubicin By Gold Hollow Nanospheres And The Laser Responsive Sequential Release

In present thesis, a gene/drug co-loading system based on hollow goldnanospheres (HGNS) was designed and the sequential releasing of as-miR-21anddoxorubicin (DOX) response to near-infrared laser was investigated.Firstly, HGNS were prepared employing Cu2O nanoparticles and silvernanoparticles as template respectively. The morphologies and spectrum properties ofHGNS were studied via transmission electron microscopy (TEM) and UV-visiblespectrophotometer measurement. The results showed that, in the case of CuO2astemplate, HGNS exhibited a porous structure which seem formed by the aggregationof gold nanoparticles, and an adsorption peaks at650nm was found. Both the amountand the method for HAuCl4addition affected the morphologies and spectrumproperties of HGNS. The shell of HGNS became more complete when theconcentration of HAuCl4increased from0to0.13mM, and a slight Red Shift wasobserved. Further increased the concentration (amount) of HAuCl4increased thethickness of shell, leading to the Blue Shift of the adsorption peak. Compared with thelittlie by littlie method, feeding the HAuCl4in one batch led the shell of HGNS morecomplete, and the peak of spectra shifted to near infrared region. Nevertheless, noHGNS obtained by this method exhibit absorption peak in near-infraredregion(800~2500nm) where the laser can penetrate deep tissue and trigger the releaseof drug from HGNs.. The HGNS with adsorption peak at960nm were successfulsynthesized with silver as template. The HGNS were well dispersed with uniform size60～70nm.Secondly, PAMAM dendrimer was covalently conjugated onto the surface ofHGNS, and as-miR-21and doxorubicin hydrochloride were co-loaded onto thePAMAM-modified HGNS (PAMAM-HGNS) by electrostatical adsorption. Theloading of DOX was demonstrated by UV-visible absorption spectrum, energydispersive spectrum analysis and confocal microscopy observation. And thecomplexation of as-miR-21was proved by agarose gel electrophoretogram.As-miR-21bound to PAMAM-HGNS at the ratio of N/P ratio over4:1and could bereleased by addition of heparin. The drug-loading rate could reach as much as30percent, and most of the DOX strongly bound with HGNS in physiological environment, but released from the surface of HGNS under the irradiation of pulsednear-infrared laser (excitation wavelength1000nm). Thus a gene and drugsequentially release system was successfully constructed.