Livery has therefore been one of the most significant challenges in siRNA therapeutics [12,13]. Currently, nanoparticles composed of PLGA are attractive for use in gene silencing applications because of their high stability, low toxicity, and the possibility for controlled release of their cargo [14?6]. Moreover, targeting has been achieved by attaching a targeting molecule or protein to these nanoparticles [17]. Our previous studies indicated that the fusion protein derived from FVII has a specific TF binding capacity but dose not cause coagulation [18] and can enhance the binding ability of PLGA nanoparticles to regions with exposed TF [19]. Thus, EGFPEGF1 modified PLGA nanoparticles may be a suitable delivery vehicle for siRNAs.siRNA-Loaded ENPs for Efficient RNA InterferenceTable 1. The particle size and zeta potential of NP and ENP with siRNA-loaded or non-loaded.Union Medical College, Beijing, China) were cultured in DMEM (high glucose) which consisted of 10 FBS and antibiotics (including 100 mg/ml of penicillin, and 100 mg/ml of streptomycin) at 37uC in a humidified atmosphere with 5 CO2.nanoparticles ENP NP siRNA/ENP siRNA/NPMean size(nm) 100.0665.12 92.8662.12 106.0863.23 96.5964.Zeta potential(mV) 212.3162.01 211.7163.98 211.1563.19 29.1160.2.3. Synthesis and in vitro Screening of siRNAsThe three siRNAs with the lowest predicted off-target potentials and 100 homology with the rat TF gene sequence NM_013057.2 were selected for synthesis and screening. The siRNAs were obtained from the Life Technologies Corporation (USA). Rat C6 glioma cells, which naturally overexpress TF, were transfected with siRNAs using the Lipofectamine 2000 reagent (Invitrogen, USA) according to the manufacturer’s protocols in concentration ranging from 10 nM to 100 nM. TF mRNA levels were quantified 24 h after transfection by real time PCR and normalized using GAPDH mRNA. The best RNAi concentration was 40 nM. The best A-196 site duplex, with the sequence of 59GCAAUGACUUGGGUUAUAUdTdT-39 (sense) and, 59AUAUAACCCAAGUCAUUGCdTdT-39 (antisense), 
was selected for scaling up, formulation and subsequent in vivo work.Measured in double-distilled water n = 3, mean6SD. doi:10.1371/journal.pone.0060860.tIn this study, TF was chosen as the therapeutic target for siRNA therapy. The endothelial cells that are injured by TNF-a overexpressed TF. The nanoparticles were composed of the biodegradable and biocompatible polymer poly-(lactic-co-glycolic acid) (PLGA) and the nanoparticles and the EGFP-EGF1 fusion protein was attached to the nanoparticle surfaces. The EGFPEGF1-conjugated PLGA nanoparticles (ENPs) were used as a new targeted carrier for TF-specific siRNA and enabled siRNA delivery into injured primary BMECs. The physical properties of the nanoparticles, the cytotoxicity of the nanoparticles, the siRNA release in vitro from the nanoparticles, and the gene silencing effect were determined. To our knowledge, this is the first time that the nanoparticle targeted delivery of TF-specific siRNA to injured primary endothelial cells has been successfully studied.2.4. Preparation of siRNA-loaded NPs and siRNA-loaded ENPsThe siRNA-loaded NPs were prepared using a water-in-oil-inwater (w/o/w) double emulsion solvent MedChemExpress PLV-2 evaporation method similar to the one previously reported [24]. In brief, a solution of 40 mg of siRNA in 50 ml of DEPC MilliQ water containing AcBSA [25] was mixed with dichloromethane (DCM) containing Me-PEG-PLGA and Mal-PEG-PLGA (weight ratio 10:1), and the mixture wa.Livery has therefore been one of the most significant challenges in siRNA therapeutics [12,13]. Currently, nanoparticles composed of PLGA are attractive for use in gene silencing applications because of their high stability, low toxicity, and the possibility for controlled release of their cargo [14?6]. Moreover, targeting has been achieved by attaching a targeting molecule or protein to these nanoparticles [17]. Our previous studies indicated that the fusion protein derived from FVII has a specific TF binding capacity but dose not cause coagulation [18] and can enhance the binding ability of PLGA nanoparticles to regions with exposed TF [19]. Thus, EGFPEGF1 modified PLGA nanoparticles may be a suitable delivery vehicle for siRNAs.siRNA-Loaded ENPs for Efficient RNA InterferenceTable 1. The particle size and zeta potential of NP and ENP with siRNA-loaded or non-loaded.Union Medical College, Beijing, China) were cultured in DMEM (high glucose) which consisted of 10 FBS and antibiotics (including 100 mg/ml of penicillin, and 100 mg/ml of streptomycin) at 37uC in a humidified atmosphere with 5 CO2.nanoparticles ENP NP siRNA/ENP siRNA/NPMean size(nm) 100.0665.12 92.8662.12 106.0863.23 96.5964.Zeta potential(mV) 212.3162.01 211.7163.98 211.1563.19 29.1160.2.3. Synthesis and in vitro Screening of siRNAsThe three siRNAs with the lowest predicted off-target potentials and 100 homology with the rat TF gene sequence NM_013057.2 were selected for synthesis and screening. The siRNAs were obtained from the Life Technologies Corporation (USA). Rat C6 glioma cells, which naturally overexpress TF, were transfected with siRNAs using the Lipofectamine 2000 reagent (Invitrogen, USA) according to the manufacturer’s protocols in concentration ranging from 10 nM to 100 nM. TF mRNA levels were quantified 24 h after transfection by real time PCR and normalized using GAPDH mRNA. The best RNAi concentration was 40 nM. The best duplex, with the sequence of 59GCAAUGACUUGGGUUAUAUdTdT-39 (sense) and, 59AUAUAACCCAAGUCAUUGCdTdT-39 (antisense), was selected for scaling up, formulation and subsequent in vivo work.Measured in double-distilled water n = 
3, mean6SD. doi:10.1371/journal.pone.0060860.tIn this study, TF was chosen as the therapeutic target for siRNA therapy. The endothelial cells that are injured by TNF-a overexpressed TF. The nanoparticles were composed of the biodegradable and biocompatible polymer poly-(lactic-co-glycolic acid) (PLGA) and the nanoparticles and the EGFP-EGF1 fusion protein was attached to the nanoparticle surfaces. The EGFPEGF1-conjugated PLGA nanoparticles (ENPs) were used as a new targeted carrier for TF-specific siRNA and enabled siRNA delivery into injured primary BMECs. The physical properties of the nanoparticles, the cytotoxicity of the nanoparticles, the siRNA release in vitro from the nanoparticles, and the gene silencing effect were determined. To our knowledge, this is the first time that the nanoparticle targeted delivery of TF-specific siRNA to injured primary endothelial cells has been successfully studied.2.4. Preparation of siRNA-loaded NPs and siRNA-loaded ENPsThe siRNA-loaded NPs were prepared using a water-in-oil-inwater (w/o/w) double emulsion solvent evaporation method similar to the one previously reported [24]. In brief, a solution of 40 mg of siRNA in 50 ml of DEPC MilliQ water containing AcBSA [25] was mixed with dichloromethane (DCM) containing Me-PEG-PLGA and Mal-PEG-PLGA (weight ratio 10:1), and the mixture wa.