title: A novel GNRs-PEI/GNRs-PEI-folate for efficiently delivering siRNA.
abstract: RNA interference (RNAi) employs double-stranded RNA or siRNA (small interfering RNA) to silence gene expression in cells. The widespread use of RNAi therapeutics requires the development of clinically suitable, safe and effective delivery vehicles. PEI (Poly(ethylene imine)) carrying the positive charges has attracted considerable attention for siRNA delivery. Gold nanorods (GNRs) exhibit specially localized surface plasmon resonance when excited by the visible and near-infrared laser, which is useful for photothermal therapy. However, the toxicity derived from a large amount of the surfactant cetyltrimethylammonium bromide (CTAB) during GNR synthesis severely limits their medical applications. Here, we report the synthesis of GNRs-PEI/GNRs-PEI-folate to improve biocompatibility, siRNA delivery and photothermal therapy of GNRs. Firstly, GNRs were synthesized according to the seed-mediated template-assisted protocol. The characterization results of GNRs showed: the size was length about 218 nm and width about 26.8 nm; the Zeta potential was +38.1 mV derived from CTAB on their surface; the dipole resonance extinction spectrum peak was 752 nm which is effective for photothermal therapy in vivo. Secondly, we synthesized PEI-MUA (Mercaptoundecanoic acid) and PEI-MUA-folate based on the chemical reaction between amino group of PEI and carboxyl group of MUA or Folate. PEI-MUA or PEI-MUA-folate to replace CTAB on GNRs obtained the GNRs-MUA-PEI system or the GNRs-MUA-PEI-folate system due to the solid conjugation between the thiol group of MUA and GNRs. The products were measured using the FTIR Spectrometer, and the spectra suggest MUA-PEI or PEI-MUA-folate has successfully replaced CTAB on the surface of GNRs. Finally, GNRs-MUA-PEI was incubated with siRNA-Cy3. The unbound siRNA-Cy3 was measured the intensity of fluorescence for calculating the uploaded amount of siRNA by GNRs-MUA-PEI, and the results indicate that the uploaded percentage of siRNA is about 70%. We conclude that the GNRs-MUA-PEI system is an effective siRNA loading vehicle.
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.|Institute of nanomedicine, Jiangxi Academy of Medical Sciences, Nanchang, Jiangxi, China.
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.|Institute of nanomedicine, Jiangxi Academy of Medical Sciences, Nanchang, Jiangxi, China.
authors.forename: Na
authors.initials: N
authors.lastname: Song
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.|Institute of nanomedicine, Jiangxi Academy of Medical Sciences, Nanchang, Jiangxi, China.
authors.forename: Jiamin
authors.initials: J
authors.lastname: Fu
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.|Institute of nanomedicine, Jiangxi Academy of Medical Sciences, Nanchang, Jiangxi, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.|Institute of nanomedicine, Jiangxi Academy of Medical Sciences, Nanchang, Jiangxi, China.
authors.forename: Yanrong
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Qiaofa
authors.initials: Q
authors.lastname: Shi
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Yingyuan
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Nanjing
authors.initials: N
authors.lastname: Zhou
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Keng
authors.initials: K
authors.lastname: Yuan
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, and Institute of Immuno- and Biotherapy, Nanchang University, Nanchang, Jiangxi, China.|Institute of nanomedicine, Jiangxi Academy of Medical Sciences, Nanchang, Jiangxi, China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Min
mesh_terms: D002470:Cell Survival; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D005492:Folic Acid / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D043942:Nanotubes / Q000737:chemistry*; D010316:Particle Size; D010789:Phototherapy / Q000379:methods*; D011095:Polyethylenes / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D013499:Surface Properties
chemical_list: D002593:Cetrimonium Compounds; D011095:Polyethylenes; D034741:RNA, Small Interfering; D006046:Gold; D005492:Folic Acid; D000077286:Cetrimonium
keywords: GNRs-PEI; GNRs-PEI-folate; photothermal therapy; siRNA delivery