Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol （PEG） and octadecylamine （ODA）, separately, was studied. Different characterization techniques such a...Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol （PEG） and octadecylamine （ODA）, separately, was studied. Different characterization techniques such as FTIR spectrometery, thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and solubility in different solvents were performed for the oxidized MWCNTs, MWCNTs-PEG and MWCNTs-ODA. The characterization techniques proved the presence of the functional groups on the MWCNTs surface. Thermal gravimetric analysis revealed that nearly 16% （by weight） of the MWCNTs were functionalized with PEG and 39% （by weight） was functionalized with ODA.展开更多
To design a releasable PEGylated TNF-α(rPEG-TNF-α ), a cathepsin B-sensitive dipeptide (Val-Cit moiety) was inserted into conventional PEG-modified TNF- (PEG-TNF- ), facilitating its clinical use for anti-tumor ther...To design a releasable PEGylated TNF-α(rPEG-TNF-α ), a cathepsin B-sensitive dipeptide (Val-Cit moiety) was inserted into conventional PEG-modified TNF- (PEG-TNF- ), facilitating its clinical use for anti-tumor therapy. Comparative pharmaco- kinetic and pharmacodynamic studies showed that the half-lives of both PEGylated forms of TNF-α were ~60-fold greater than that of unmodified TNF-α . In addition, the in vitro bioactivity of rPEG-TNF-α was greater than that of PEG-TNF-α with the same degree of PEG modification. Release of TNF-α from rPEG-TNF-α in vitro was dependent on the presence of cathepsin B and was inhibited by a cathepsin B inhibitor. Despite the potent cytotoxicity of unmodified TNF-α against normal cells, its PEGylated forms at higher TNF-α concentrations showed low cytotoxic activity against these cells. In contrast, both forms of PEGylated TNF-α showed potent cytotoxic activity against the B16 and L929 cell lines, with rPEG-TNF-α being 5- and 9- fold more potent, respectively, than PEG-TNF-α . Moreover, rPEG-TNF-α was a more potent in vivo antitumor agent than PEG-TNF-α .展开更多
文摘Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol （PEG） and octadecylamine （ODA）, separately, was studied. Different characterization techniques such as FTIR spectrometery, thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and solubility in different solvents were performed for the oxidized MWCNTs, MWCNTs-PEG and MWCNTs-ODA. The characterization techniques proved the presence of the functional groups on the MWCNTs surface. Thermal gravimetric analysis revealed that nearly 16% （by weight） of the MWCNTs were functionalized with PEG and 39% （by weight） was functionalized with ODA.
基金supported by the National Natural Science Foundation of China (30701055)in part by the China Postdoctoral Science Foundation(20070410029)in part by the Foundation of Innovation Team at the Chongqing University of Science and Technology (2007)
文摘To design a releasable PEGylated TNF-α(rPEG-TNF-α ), a cathepsin B-sensitive dipeptide (Val-Cit moiety) was inserted into conventional PEG-modified TNF- (PEG-TNF- ), facilitating its clinical use for anti-tumor therapy. Comparative pharmaco- kinetic and pharmacodynamic studies showed that the half-lives of both PEGylated forms of TNF-α were ~60-fold greater than that of unmodified TNF-α . In addition, the in vitro bioactivity of rPEG-TNF-α was greater than that of PEG-TNF-α with the same degree of PEG modification. Release of TNF-α from rPEG-TNF-α in vitro was dependent on the presence of cathepsin B and was inhibited by a cathepsin B inhibitor. Despite the potent cytotoxicity of unmodified TNF-α against normal cells, its PEGylated forms at higher TNF-α concentrations showed low cytotoxic activity against these cells. In contrast, both forms of PEGylated TNF-α showed potent cytotoxic activity against the B16 and L929 cell lines, with rPEG-TNF-α being 5- and 9- fold more potent, respectively, than PEG-TNF-α . Moreover, rPEG-TNF-α was a more potent in vivo antitumor agent than PEG-TNF-α .
