Stimuli‐responsive nanocarriers with the ability to respond to tumorous heterogeneity have been extensively developed for drug delivery. However, the premature release during blood circulation and insufficient intracellular drug release are still a significant issue. Herein, three disulfide bonds are introduced into the amphiphilic poly(ethylene glycol)‐polycaprolactone copolymer blocks to form triple‐sensitive cleavable polymeric nanocarrier (tri‐PESC NPs) to improve its sensitivity to narrow glutathione (GSH) concentration. The tri‐PESC NPs keep intact during blood circulation due to the limited cleaving of triple‐disulfide bonds, whereas the loaded drug is efficiently released at tumor cells with the increased concentration of GSH. In vitro studies of doxorubicin‐loaded tri‐PESC NPs show that the nanocarriers achieve sufficient drug release in cancerous cells and inhibit the tumor cells growth, though they only bring minimum damage to normal cells. Therefore, the tri‐PESC NPs with triple‐sensitive cleavable bonds hold great promise to improve the therapeutic index in cancer therapy.
Di(4,5,6,7-tetrafluorobenzothiazol-2-yl) disulfide, obtained by oxidation of 2-mercapto-4,5,6,7-tetrafluorobenzothiazole,
readily reacts with aliphatic and alicyclic amines to form the corresponding sulfenyl amides.
Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1225–1226, June, 2007. 相似文献
Improved Syntheses, Crystal Growth, and Crystal Structure Determination of P4O6S2 and P4O6S3 Syntheses and single crystal growths of the title compounds are described. Both compounds crystallize in the space group P21/c (P4O6S2: a = 11.293(4); b = 6.457(3); c = 11.588(4) Å; β = 90.29(2)°, 2 450 diffractometer data, Rw = 0.035/P4O6S3: a = 15.611(5); b = 8,303(3); c = 9.697(4) Å; β = 127.12(2)°, 2 481 diffractometer data, Rw = 0.034). The structural data for the series P4O6Sn (n = 1 – 4) thus completed are compared to their oxide analogues P4O6On (n = 1 – 4). The changes in the geometry of the P4O6-cage in course of its successive oxidation are discussed. 相似文献
Disulfide reduction of Kluyveromyces lactis and Aspergillus oryzae β-galactosidases and β-lactoglobulin was assessed. Reduction was performed using one of two thiol-containing agents: dithiothreitol
(DTT) or thiopropyl-agarose with a high degree of substitution (1000 μmol of SH groups/g of dried gel). Both reductants allowed
an increase of three- (for K. lactis β-galactosidase) and fourfold (for A. oryzae β-galactosidase) in the initial content of SH groups in the lactases. Nearly sevenfold fewer micromoles of SH groups per
milligram of protein were needed to perform the reduction of K. lactis β-galactosidase with thiopropyl-agarose than for the same reduction with DTT. However, for A. oryzae β-galactosidase, nearly twice as many micromoles of SH groups per milligram of protein were needed with thiopropylagarose
than with DTT. Disulfide bonds in β-lactoglobulin were not accessible to thiopropyl-agarose, since this reduction was only
possible in the presence of 6 M urea. These results proved that highly substituted thiopropyl-agarose is as good a reducing agent as DTT, for the reduction
of disulfide bonds in proteins. Moreover, excess reducing agent was very simply separated from the reduced protein by filtration,
making it easier to control the reaction and providing reduced protein solutions free of reductant. All these advantages substantially
cut down the time required and therefore the cost of the overall process. 相似文献
The reaction of thiolate anions, generated in situ by indium(I) iodide promoted cleavage of dialkyl/diaryl disulfides, with styrenes has been investigated. Thiolate anions add to a variety of styrenes in an anti-Markovnikov manner producing linear thioethers in high yields. This method provides a new route to the synthesis of thioethers. 相似文献
下载免费PDF全文