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Size effect of Au/PAMAM contrast agent on CT imaging of reticuloendothelial system and tumor tissue

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ABSTRACT

Polyamidoamine (PAMAM)-entrapped Au nanoparticles were synthesized with distinct sizes to figure out the size effect of Au-based contrast agent on CT imaging of passively targeted tissues. Au/PAMAM nanoparticles were first synthesized with narrow distribution of particles size of 22.2 ± 3.1, 54.2 ± 3.7, and 104.9 ± 4.7 nm in diameters. Size effect leads no significant difference on X-ray attenuation when Au/PAMAM was ≤0.05 mol/L. For CT imaging of a tumor model, small Au/PAMAM were more easily internalized via endocytosis in the liver, leading to more obviously enhanced contrast. Similarly, contrast agents with small sizes were more effective in tumor imaging because of the enhanced permeability and retention effect. Overall, the particle size of Au/PAMAM heavily affected the efficiency of CT enhancement in imaging RES and tumors.

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Synthetic scheme and characteristics of Au-based CT contrast agents with gradient sizes. a Synthesis of PAMAM-entrapped Au. b–d TEM of Au nanoparticles in 22.2 ± 3.1, 54.2 ± 3.7, and 104.9 ± 4.7 nm. e Typical example of PAMAM-entrapped Au. f Size distributions of Au with three distinct sizes
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Fig1: Synthetic scheme and characteristics of Au-based CT contrast agents with gradient sizes. a Synthesis of PAMAM-entrapped Au. b–d TEM of Au nanoparticles in 22.2 ± 3.1, 54.2 ± 3.7, and 104.9 ± 4.7 nm. e Typical example of PAMAM-entrapped Au. f Size distributions of Au with three distinct sizes

Mentions: The schematic procedure of Au/PAMAM contrast agents is shown in Fig. 1a. HAuCl4 was dissolved in 100 mL distilled water at 0.1 mg/mL and then heated to 100 °C in nitrogen atmosphere. A suitable amount of sodium citrate solution at 10 mg/mL was added as a reducing agent, and reaction system was refluxed for another 10 min. After naturally cooling down, Au nanoparticles were collected and purified via centrifuging at 12,000 rpm for 1 min. Surface coating was performed following an established method [22, 23]. The fifth generation (G5.0) PAMAM dendrimers in methanol were mixed with N-hydroxysuccinimidyl 3-mercaptopropanoate in 1:1 mixed solution of tetrahydrofuran and methanol and vortexed for 1 h at room temperature. The PAMAM-SH and AuNPs reacted overnight utilizing the strong affinity between thiol groups and AuNPs and product was collected via centrifuging as well.Fig. 1


Size effect of Au/PAMAM contrast agent on CT imaging of reticuloendothelial system and tumor tissue
Synthetic scheme and characteristics of Au-based CT contrast agents with gradient sizes. a Synthesis of PAMAM-entrapped Au. b–d TEM of Au nanoparticles in 22.2 ± 3.1, 54.2 ± 3.7, and 104.9 ± 4.7 nm. e Typical example of PAMAM-entrapped Au. f Size distributions of Au with three distinct sizes
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5037097&req=5

Fig1: Synthetic scheme and characteristics of Au-based CT contrast agents with gradient sizes. a Synthesis of PAMAM-entrapped Au. b–d TEM of Au nanoparticles in 22.2 ± 3.1, 54.2 ± 3.7, and 104.9 ± 4.7 nm. e Typical example of PAMAM-entrapped Au. f Size distributions of Au with three distinct sizes
Mentions: The schematic procedure of Au/PAMAM contrast agents is shown in Fig. 1a. HAuCl4 was dissolved in 100 mL distilled water at 0.1 mg/mL and then heated to 100 °C in nitrogen atmosphere. A suitable amount of sodium citrate solution at 10 mg/mL was added as a reducing agent, and reaction system was refluxed for another 10 min. After naturally cooling down, Au nanoparticles were collected and purified via centrifuging at 12,000 rpm for 1 min. Surface coating was performed following an established method [22, 23]. The fifth generation (G5.0) PAMAM dendrimers in methanol were mixed with N-hydroxysuccinimidyl 3-mercaptopropanoate in 1:1 mixed solution of tetrahydrofuran and methanol and vortexed for 1 h at room temperature. The PAMAM-SH and AuNPs reacted overnight utilizing the strong affinity between thiol groups and AuNPs and product was collected via centrifuging as well.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Polyamidoamine (PAMAM)-entrapped Au nanoparticles were synthesized with distinct sizes to figure out the size effect of Au-based contrast agent on CT imaging of passively targeted tissues. Au/PAMAM nanoparticles were first synthesized with narrow distribution of particles size of 22.2 ± 3.1, 54.2 ± 3.7, and 104.9 ± 4.7 nm in diameters. Size effect leads no significant difference on X-ray attenuation when Au/PAMAM was ≤0.05 mol/L. For CT imaging of a tumor model, small Au/PAMAM were more easily internalized via endocytosis in the liver, leading to more obviously enhanced contrast. Similarly, contrast agents with small sizes were more effective in tumor imaging because of the enhanced permeability and retention effect. Overall, the particle size of Au/PAMAM heavily affected the efficiency of CT enhancement in imaging RES and tumors.

No MeSH data available.