Siyuan Han

National Center for Nanoscience and Technology, Peping, Beijing, China

Are you Siyuan Han?

Claim your profile

Publications (7)25.13 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, novel cyclosporine A (CsA)-loaded amphiphilic poly(L-aspartic acid-co-L-lactic acid) (PAL)-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) copolymer nanoparticles (NPs) were successfully fabricated using an emulsion/solvent evaporation technique. The CsA-loaded NPs were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The CsA-loaded NPs size, size distribution, encapsulation efficiency (EE) and drug-loading content (LC) were influenced by polyvinyl alcohol (PVA) concentration and the weight ratio of the copolymer to CsA. In vitro release behavior of CsA-loaded NPs showed a sustained release. With the increasing of copolymer/CsA weight ratio, the release of CsA from NPs is rapid. The poly(L-aspartic acid) derivatives NPs have a promising potential in hydrophobic drug delivery system.
    Journal of Nanoscience and Nanotechnology 02/2013; 13(2):1444-7. · 1.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The use of biodegradable polymeric nanoparticles (NPs) for controlled drug delivery has shown significant therapeutic potential. Polyaspartic acid and polylactic acid are the most intensively studied biodegradable polymers. In the present study, novel amphiphilic biodegradable co-polymer NPs, poly(L-aspartic acid-co-lactic acid) with 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) (poly(AA-co-LA)/DPPE) is synthesized and subsequently used to encapsulate an antitumor drug doxorubicin (DOX). The formulation parameters of the NPs are optimized to improve encapsulation efficiency. The resulting drug-loaded NPs possess better size homogeneity (polydispersity) and exhibit pH-responsive drug release profiles. Cellular viability assays indicate that the poly(AA-co-LA)/DPPE NPs did not induce cell death, whereas doxorubicin encapsulated NPs were cytotoxic to various types of tumor cells. In addition, the free NPs could not enter the cell nuclei after internalized in tumor cells. The DOX-loaded NPs exhibit efficient intracellular delivery in tumor cells with co-localization in lysosome and delay entering into the nucleus, which suggests a time- and pH-dependent drug release profile within cells. When applied to deliver chemotherapeutics to a mouse xenograft model of human lung adenocarcinoma, DOX-loaded NPs have a comparable antitumor activity with free DOX, and greatly reduce systemic toxicity and mortality. The delivery of cytotoxic drugs directly to the nucleus specifically within tumor cells is of great interest. These results demonstrate the feasibility of the application of the amphiphilic polyaspartic acid derivative, poly(AA-co-LA)/DPPE, as a nanocarrier for cell nuclear delivery of potent antitumor drugs.
    Small 03/2012; 8(10):1596-606. · 7.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this work, biodegradable amphiphilic copolymer nanoparticles based on dextran, polylactide (PLA), and 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphoethanolamine (DPPE) were prepared. To estimate their feasibility as drug carriers, an antitumor model drug, mitoxantrone (MTO), was successfully incorporated into the polymeric nanoparticles by double‐emulsion (DE) and nanoprecipitation (NP) methods. The MTO‐loaded nanoparticles were confirmed by dynamic light scattering and transmission electron microscopy. The MTO‐loaded nanoparticle size, size distribution, and encapsulation efficiency were influenced by the feed weight ratio of the copolymer to MTO. In addition, in vitro release experiments showed that the release behavior was affected by the fabrication method and the pH of the release media. The MTO‐loaded nanoparticles showed faster release by the NP method and at pH 5.4 than by the DE method and in pH 7.4 buffer. The dextran–PLA–DPPE polymeric nanoparticles could be useful as drug carriers for antitumor drug delivery. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
    Journal of Applied Polymer Science 01/2012; 126. · 1.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Novel amphiphilic copolymer nanoparticles (HPAE-co-PLA-DPPE) composed of hyperbranched poly (amine-ester), polylactide and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) segments were designed and synthesized that provided high encapsulation efficiency. These nanoparticles (NPs) were used to encapsulate an antitumor model drug, doxorubicin (DOX). The resulting NPs exhibited high encapsulation efficiency to DOX under an appropriate condition. In vitro release experiments revealed that the release of DOX from NPs was faster at pH 4.5 than that at pH 7.4 or pH 6.0. Confocal microscopy observation indicated that the DOX-loaded NPs can enter cells and localize in lysosomes that can be released quickly into the cytoplasm. The DOX-loaded NPs showed comparable anticancer efficacy with the free drug both in vivo and in vitro. These results demonstrate a feasible application of the hyperbranched copolymer, HPAE-co-PLA-DPPE, as a promising nanocarrier for intracellular delivery of antitumor drugs. FROM THE CLINICAL EDITOR: In this paper, the development of novel amphiphilic copolymer nanoparticles is discussed with the goal of establishing high encapsulation efficiency for chemotherapy drugs.
    Nanomedicine: nanotechnology, biology, and medicine 05/2011; 7(6):945-54. · 6.93 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel amphiphilic copolymer based on dextran, poly(lactide) (PLA) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) was synthesized and characterized by FT-IR, 1H NMR, 13C NMR and 31P NMR spectra. Their molecular weights were determined by gel permeation chromatography (GPC). The molecular weights range from 30 000 g mol−1 to 37 000 g mol−1 with a feed weight ratio of 20:1–50:1 (DPPE/activated dextran–PLA). Its micellar characteristics were investigated using fluorescence technique, transmission electron microscopy (TEM) and dynamic light scattering (DLS). It was found that dextran–PLA–DPPE copolymer could form spherical micelles. The micelle diameters ranged from 85 to 120 nm with a feed weight ratio of 20:1–50:1 (DPPE/activated dextran–PLA) in the absence of surfactant.
    Carbohydrate Polymers 01/2011; 83(3):1408-1413. · 3.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel poly(l-aspartic) derivative (PAL-DPPE) containing polylactide and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) segments has been successfully synthesized. The chemical structures of the copolymers were confirmed by Fourier-transform infrared spectroscopy (FTIR), NMR (1H NMR, 13C NMR, 31P NMR), and thermogravimetric analysis (TGA). Fluorescence spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM) confirmed the formation of micelles of the PAL-DPPE copolymers. In order to estimate the feasibility as novel drug carriers, an anti-tumor model drug doxorubicin (DOX) was incorporated into polymeric micelles by double emulsion and nanoprecipitation method. The DOX-loaded micelle size, size distribution, and encapsulation efficiency (EE) were influenced by the feed weight ratio of the copolymer to DOX. In addition, in vitro release experiments of the DOX-loaded PAL-DPPE micelles exhibited that faster release in pH 5.0 than their release in pH 7.4 buffer. The poly(l-aspartic) derivative copolymer was proved to be an available carrier for the preparation of micelles for anti-tumor drug delivery. Keywords l-Aspartic acid–Polylactide–1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine–Nanoparticles–Doxorubicin delivery system–Nanomedicine
    Journal of Nanoparticle Research 01/2011; 13(9):4371-4385. · 2.18 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel amphiphilic copolymer with p-maleimidophenyl isocyanate-hydroxypropyl-β-cyclodextrin-polylactide-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine to generate copolymer nanoparticles (NPs) has been designed. In order to develop an active targeting system, integrin αvβ3-specific targeting peptide cyclo(Arg-Gly-Asp-D-Phe-Cys), cRGD, was conjugated to the surface of NPs (NPs-RGD). These NPs were used to encapsulate anti-tumor drug, paclitaxel. The resulting NPs exhibited high drug-loading capacity and controlled drug release in vitro at acidic pH. In vitro cytotoxicity assay demonstrates that paclitaxel-loaded NPs-RGD significantly inhibited B16 tumor cell (high αvβ3) proliferation relative to free paclitaxel and paclitaxel-loaded NPs at high concentrations. Paclitaxel-loaded NPs-RGD localized mainly in lysosomes in B16 cells as revealed by confocal microscopy. These results suggest a novel strategy for fabrication—functionalizing hydroxypropyl-β-cyclodextrin copolymer nanoparticles for targeting delivery of paclitaxel to integrin αvβ3-rich tumor cells. These nanocarriers can be readily extended to couple other bioactive molecules for active targeting and delivery of various chemotherapeutic drugs.
    Journal of Nanoparticle Research 14(8). · 2.18 Impact Factor