A novel graphene oxide-doxorubicin hydrochloride nanohybrid (GO-DXR) was prepared via a simple noncovalent method, and the loading and release behaviors of DXR on GO were investigated. An efficient loading of DXR on GO as high as 2.35 mg/mg was obtained at the initial DXR concentration of 0.47 mg/mL. The loading and release of DXR on GO showed strong pH dependence, which may be due to the hydrogenbonding interaction between GO and DXR. The fluorescent spectrum and electrochemical results indicate that strong π-π stacking interaction exists between them.
A superparamagnetic graphene oxide -Fe 3 O 4 nanoparticles hybrid (GO-Fe 3 O 4 ) was prepared via a simple and effective chemical precipitation method. The amount of loading of Fe 3 O 4 on GO was estimated as 18.6 wt% by atomic absorption spectrometry. The hybrid was then loaded with doxorubicin hydrochloride (DXR) and the loading capacity was as high as 1.08 mg mg À1 . Both of the GO-Fe 3 O 4 hybrids before and after loading with DXR can be dispersed well in aqueous solution. They can congregate under acidic conditions and move regularly under the force of an external magnet. Furthermore, the aggregated hybrid can be redispersed to form a stable suspension under basic conditions. These properties make it a potential candidate for controlled targeted drug delivery and release.
A dual-targeting drug delivery and pH-sensitive controlled release system based on multifunctionalized graphene oxide (GO) was established in order to enhance the effect of targeted drug delivery and realize intelligently controlled release. A superparamagnetic GO-Fe 3 O 4 nanohybrid was firstly prepared via a simple and effective chemical precipitation method. Then folic acid, a targeting agent toward some tumor cells, was conjugated onto Fe 3 O 4 nanoparticles via the chemical linkage with amino groups of the 3-aminopropyl triethoxysilane (APS) modified superparamagnetic GO-Fe 3 O 4 nanohybrid, to give the multi-functionalized GO. Doxorubicin hydrochloride (Dox) as an anti-tumor drug model was loaded onto the surface of this multi-functionalized GO via p-p stacking. The drug loading capacity of this multi-functionalized GO is as high as 0.387 mg mg À1 and the drug release depends strongly on pH values. Cell uptake studies were carried out using fluorescein isothiocyanate labeled or Dox loaded multi-functionalized GO to evaluate their targeted delivery property and toxicity to tumor cells. The results show that this multi-functionalized GO has potential applications for targeted delivery and the controlled release of anticancer drugs.
Purpose: To determine whether -CONH-(CH 2 ) 6 -NH 3 + Cl À functionalized single-walled carbon nanotubes (SWNT) carrying complexed small interfering RNA (siRNA) can enter into tumor cells, wherein they release the siRNA to silence the targeted gene. Experimental Design: -CONH-(CH 2 ) 6 -NH 3 + Cl À was used to mediate the conjugation of telomerase reverse transcriptase (TERT) siRNA to SWNTs. The ability of TERT siRNA delivered via SWNTcomplexes to silence the expression of TERT was assessed by their effects on the proliferation and growth of tumor cells both in vitro and in mouse models. Results: The functionalized SWNTs -CONH-(CH 2 ) 6 -NH 3 + Cl À could facilitate the coupling of siRNAs that specifically target murine TERT expression to form the mTERT siRNA:SWNT+ complex. These functionalized SWNTs rapidly entered three cultured murine tumor cell lines, suppressed mTERT expression, and produced growth arrest. Injection of mTERT siRNA:SWNT+ complexes into s.c. Lewis lung tumors reduced tumor growth. Furthermore, human TERT siRNA:SWNT+ complexes also suppressed the growth of human HeLa cells both in vitro and when injected into tumors in nude mice. Conclusions: -CONH-(CH 2 ) 6 -NH 3 + Cl À functionalized SWNTs carry complexed siRNA into tumor cells, wherein they release the siRNA from the nanotube sidewalls to silence the targeted gene.The -CONH-(CH 2 ) 6 -NH 3 + Cl À functionalized SWNTs may represent a new class of molecular transporters applicable for siRNA therapeutics.
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