Stable Dispersions of Covalently Tethered Polymer Improved Graphene Oxide Nanoconjugates as an Effective Vector for siRNA Delivery

Abstract

Conjugates of poly(amidoamine) (PAMAM) with modified graphene oxide (GO) are attractive nonviral vectors for gene-based cancer therapeutics. GO protects siRNA from enzymatic cleavage and showed reasonable transfection efficiency along with simultaneous benefits of low cost and large scale production. PAMAM is highly effective in siRNA delivery but suffers from high toxicity with poor in vivo efficacy. Co-reaction of GO and PAMAM led to aggregation and more importantly, have detrimental effect on stability of dispersion at physiological pH preventing their exploration at clinical level. In the current work, we have designed, synthesized, characterized and explored a new type of hybrid vector (GPD), using GO synthesized via improved method which was covalently tethered with poly(ethylene glycol) (PEG) and PAMAM. The existence of covalent linkage, relative structural changes and properties of GPD is well supported by Fourier transform infrared (FTIR), UV-visible (UV-vis), Raman, X-ray photoelectron (XPS), elemental analysis, powder X-ray diffraction (XRD), thermogravimetry analysis (TGA), dynamic light scattering (DLS), and zeta potential. Scanning electron microscopy (SEM), and transmission electron microscopy (TEM) of GPD showed longitudinally aligned columnar self-assembled ∼10 nm thick polymeric nanoarchitectures onto the GO surface accounting to an average size reduction to ∼20 nm. GPD revealed an outstanding stability in both phosphate buffer saline (PBS) and serum containing cell medium. The binding efficiency of EPAC1 siRNA to GPD was supported by gel retardation assay, DLS, zeta potential and photoluminescence (PL) studies. A lower cytotoxicity with enhanced cellular uptake and homogeneous intracellular distribution of GPD/siRNA complex is confirmed by imaging studies. GPD exhibited a higher transfection efficiency with remarkable inhibition of cell migration and lower invasion than PAMAM and Lipofectamine 2000 suggesting its role in prevention of breast cancer progression and metastasis. A significant reduction in the expression of the specific protein against which siRNA was delivered is revealed by Western blot assay. Furthermore, a pH-triggered release of siRNA from the GPD/siRNA complex was studied to provide a mechanistic insight toward unloading of siRNA from the vector. Current strategy is a way forward for designing effective therapeutic vectors for gene-based antitumor therapy.

<p>Efficient miRNA Inhibitor with GO-PEI Nanosheets for Osteosarcoma Suppression by Targeting PTEN</p>

“…33 GO has been considered an ideal vector for gene delivery. 34,35 In this study, we demonstrated that GO-PEI was an effective nonviral carrier for miRNA delivery to suppress osteosarcoma cancer progression. GO bonded to PEI by electrostatic interactions and formed GO-PEI complexes with a positive charge (Figure 2).…”

Preparation of PVDF/Hyperbranched-Nano-Palygorskite Composite Membrane for Efficient Removal of Heavy Metal Ions

“…The stronger peak at approximately 399.8eV was attributed to the amine nitrogen (N–C). The amide nitrogen (O=C–N) occurred at approximately 401.9 eV as a result of the delocalization of the lone pair of electrons of O=C–N [38]. These analyses clearly indicated that PAMAM dendrimers were successfully grafted on the Pal surface.…”

Preparation, characterization and evaluation of solid lipid nanoparticles and niosomes for ING4 gene delivery to MCF-7 cells

“…Decrease in zeta potential values can be explained with the negative charge of pcDNA3-ING4 which was measured as -7.32 ± 5.35 mV. As a result, obtained net particle size and zeta potential values after the complexation procedure are sufficient for an efficient transfection [16].…”