Wei-Ti Kuo

National Taiwan University, T’ai-pei, Taipei, Taiwan

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Publications (7)12.94 Total impact

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    ABSTRACT: Cell adhesion efficiency is one of the key factors affecting the results of manufacturing tissue engineering constructs. High efficiency is required for seeding low proliferation cells onto scaffolds. In this study, we designed a strategy to improve the efficiency of cell adhesion using hydrophobic cell culture environment to enhance cells adhering to a scaffold. Cells have lower affinity to the surface of polydimethylsiloxane (PDMS) than tissue culture polystyrene (TCPS) plates. When cells were cultured with gelatin microspheres or chitosan films in a PDMS-coated plate instead of a normal TCPS plate, there was a significant increase in cell attachment efficiency. Cells cultured in the PDMS-coated system tended to selectively attach onto the gelatin microspheres or chitosan films, which are relatively more hydrophilic than the PDMS surface. However, minimal cell attachment on gelatin microspheres or chitosan films was observed when gelatin microspheres or chitosan films were placed in normal TCPS plate. Cell counting experiments with gelatin microspheres in the PDMS-coated system resulted in a cell attachment efficiency of 89.8% after 1 day of cultivation, whereas the cell attachment efficiency was less than 1% in normal TCPS plate. The results demonstrate that the method is easy to use and could be useful for fast cultivation of cell-scaffold constructs.
    Journal of Biomedical Materials Research Part B Applied Biomaterials 07/2011; 98(1):38-46. DOI:10.1002/jbm.b.31829 · 2.33 Impact Factor
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    ABSTRACT: Nonviral gene carriers composed of biodegradable polymers or lipids have been considered as a safer alternative for gene carriers over viral vectors. We have developed multifunctional nanomicelles for both drug and gene delivery application. Polyethylenimine (PEI) was modified by grafting stearic acid (SA) and further formulated to polymeric micelles (PEI-SA) with positive surface charge for gene delivery evaluation. Our results showed that PEI-SA micelles provided high siRNA binding efficiency and exhibited low cytotoxicity compared with unmodified PEI. siRNA delivered by PEI-SA carriers also demonstrated significantly higher cellular uptake efficiency and stability even in the presence of serum proteins when compared with free siRNA. The post-transcriptional gene silencing efficiency was greatly improved by the polyplex formulated by 10k PEI-SA/siRNA. In the animal intratumoral model study, the combination of co-delivering doxorubicin and vascular endothelial growth factor (VEGF) siRNA delivered by PEI-SA micelles showed a promising effect on anti-tumor growth. The amphiphilic structure of PEI-SA micelles provides advantages for multifunctional tasks; such that hydrophilic shell modified with cationic charges can electrostatically interact with DNA or siRNA, and hydrophobic core can serve as a payload for hydrophobic drugs, making it truly a promising multifunctional vehicle for both genetic and chemotherapy application.
    Journal of Biomedical Materials Research Part A 06/2011; 97(3):330-8. DOI:10.1002/jbm.a.33055 · 2.83 Impact Factor
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    ABSTRACT: A novel carrier on balancing the transfection efficiency and minimizing cytotoxicity was designed. Gelatin cross-linked with 1.8 kDa of PEI (GA-PEI 1.8 k) formed stable complex and resulted in high positive ζ potential (42.47 mV) and buffering effect. These nanoparticles with N/P ratio of 30 give high transfection efficiency 2.12 × 10 4 RLU/μg protein and cell viability (86.4%). These modified GA-PEI nanoparticles, with high transfection efficiency and low cell toxicity, can be a potential gene vector in gene therapy.
    Journal of Nanomaterials 01/2011; 646538(5). DOI:10.1155/2011/646538 · 1.61 Impact Factor
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    ABSTRACT: Non-viral vectors composed of biodegradable polymers or lipids have been considered as a safer alternative for gene carriers over viral vectors. Among some of the cationic polymers, polyethyleneimine (PEI) possess high pH-buffering capacity that can provide protection to nucleotides from acidic degradation and promotes endosomal and lysosomal release. However, it has been reported that cytotoxicity of PEI depends on the molecular weight of the polymer. Hence modifications of PEI structure for clinical application have been developed in order to reduce the cytotoxicity, or improve the insufficient transfection efficiency of lower molecular weight PEI. In this study, 10 k PEI was modified by grafting stearic acid (SA) and formulated to polymer micelles with positive surface charge and evaluated for pDNA delivery. The amine group on PEI was crosslinked with the carboxylic group of stearic acid by 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide (EDC) as linker. PEI-SA micelles were then prepared using oil in water (o/w) solvent evaporation method. The success of PEI-SA conjugation structure was confirmed with 1H NMR. The average diameter and zeta potential determined by photon correlation spectroscopy was 149.6 +/- 1.2 nm and 64.1 +/- 1.5 mV, respectively. These self-assemble positive charge micelles showed effective binding to pDNA for transfection. PEI-SA micelles exhibited lower cytotoxicity compared to that of PEI only, while flow cytometry analysis revealed PEI-SA/pEGFP complex provided 62% high EGFP expression. Luciferase activity also showed high transfection efficiency of PEI-SA micelles for weight ratio above 4.5 that was comparable to PEI only. These results demonstrated that stearic acid grafted PEI micelles can provide high transfection efficiency comparable to unmodified PEI, and exhibit low cytotoxicity. Stearic acid grafted PEI micelles can be promising polymer carriers in genetic therapy.
    Journal of Nanoscience and Nanotechnology 09/2010; 10(9):5540-7. DOI:10.1166/jnn.2010.2454 · 1.34 Impact Factor
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    ABSTRACT: Understanding and controlling the interactions between nanoscale objects and living cells is of great importance for diagnostic imaging and therapeutic applications. Quantum dots (QDs) have remarkable optical characteristics, such as uniquely feature bright, photostable, tunable and narrow fluorescence emissions, as well as broad absorption spectra. Here we report a platform of using quantum dots to investigate the cell uptake and the interactions between nanoscale objects and cells. QDs are uptaken by BHK cells easily through endocytosis. We could clearly differentiate the QDs outside the cell or inside the cell by quenching the QDs with similar sized gold nanoparticles and reduce the noise of fluorescent image. Microscopic images show that QDs are homogeneously distributed within the whole cell except the nucleus. However, unmodified QDs could not penetrate the nuclear membrane and move into the nucleus. Coupling QDs with Nuclear Localization Signal (NLS, CGGGPKKKRKVGG) can significantly enhance the translocation amount of QDs into the cell and cell nucleus. This method combined with microscopy imaging system can visualize the particle delivery routes and provide valuable information in the drug/gene delivery and tumor diagnosis.
    Journal of Nanoscience and Nanotechnology 07/2010; 10(7):4173-7. DOI:10.1166/jnn.2010.2193 · 1.34 Impact Factor
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    ABSTRACT: Gene delivery remains to be a very challenging field to efficiently transport the therapeutic gene and to modulate proteins with the desired function at the target site. The physiochemical and biological barriers are the major hurdles that need to be considered, particularly when administered systematically, in order to optimize the therapeutic efficacy. Numerous modifications have been extensively investigated aiming to provide protection from the plasma degradation, enhancement of transfection, target specificity, and most importantly, minimizing the side effects such as cellular toxicity and immune response. This article provides a review with respect to the in vitro and in vivo toxicity, as well as cellular and physiological interactions with the gene delivery system composed from viral vectors, cationic lipids and polymers. Recent progress and development are also addressed, with promising results that may be further adopted for clinical use.
    Current Drug Metabolism 10/2009; 10(8):885-94. DOI:10.2174/138920009790274504 · 3.49 Impact Factor
  • Journal of Bionanoscience 12/2008; 2(2):109-113. DOI:10.1166/jbns.2008.030