Palladium(II) complexes of glycoconjugated porphyrin and pyrrolidine-fused chlorin were prepared to examine sugar and heavy atom effects on in vitro photocytotoxicity. Cellular uptake into HeLa cells was enhanced by introducing sugar units regardless of other features, such as the central ion (free base or palladium(II) ion) and the ring structure (porphyrin or chlorin). The palladium(II) complex of glycoconjugated pyrrolidine-fused chlorin (PdPC2) exerted an excellent degree of photocytotoxicity not only on HeLa cells, but also on metastatic B16-BL6 cells, weakly metastatic B16F1 cells, and metastatic 4T1 cells. However, free-base glycoconjugated pyrrolidine-fused chlorin (PC2) also exerted similar or much higher photocytotoxicity rather than PdPC2. Therefore, the palladium(II) ion did not improve the in vitro photocytotoxicity of PC2. The enhanced singlet oxygen generation of palladium(II) complexes (i.e., the heavy atom effect) was confirmed at least in O(2)-saturated D(2)O. In addition, the formation of hydrogen peroxide and hydroxyl radical were also detected in O(2)-saturated phosphate buffered saline. However, the reactive oxygen species (ROS) generation efficiency, which is the product of the (relative) quantum yield of each ROS and the light absorbing ability, did not fit the trends of photocytotoxicity seen for the photosensitizers. In our glycoconjugated photosensitizers tested, the best indicator of the photocytotoxicity was found to be the light absorbing ability (namely, the oscillator strength in the wavelength region applied in the photocytotoxicity test). These results indicated that photochemical characteristics of glycoconjugated photosensitizers were notably susceptible to the microenvironment. The biological characteristics, such as the sugar effect, were a much more reliable approach to improving the photocytotoxicity of photosensitizers.

trans-Bisthioglycosylated tetrakis(fluorophenyl)chlorin (7) was designed as a powerful photodynamic therapy (PDT) photosensitizer based on the findings of our systematic studies. We show here that the trans-bisthioglycosylated structure of 7 enhanced its uptake by HeLa cells and that the chlorin ring of 7 increased the efficiency of reactive oxygen species generation under the standard condition of our photocytotoxicity test. The versatility of 7 in PDT treatment was established using weakly metastatic B16F1 melanoma cells, metastatic 4T1 breast cancer cells, the RGK-1 gastric carcinoma mucosal cell line, and three human glioblastoma cell lines (U87, U251, and T98G). The pharmacokinetics of 7 in mice bearing 4T1 breast cancer cells showed a high tumor-to-skin concentration ratio (approximately 60) at 24 h after intraperitoneal injection. The PDT efficacy of 7 in vivo was approximately 250-times higher than that of mono-l-aspartyl chlorin e6 (9) in mice bearing 4T1 breast cancer cells.

To examine the versatility of the trans-bisglycoconjugation architecture for 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP) derivative-based photodynamic therapy (PDT), 25 porphyrin derivatives bearing d-glucopyranose moieties were prepared, and their in vitro photocytotoxicities were examined. trans-Bisglycoconjugated TFPP derivatives exerted the best photocytotoxicity among TFPP derivatives in the same category, regardless of the central metal ion and the type of glycoconjugation. trans-Bisglycoconjugated free-base TFPP bearing β-d-glucopyranosylthio groups (trans-H22SGlc) was found to be the most potent photosensitizer, not only in HeLa cells (EC50 < 5 nM), but also in highly metastatic cancer cell lines such as B16-BL6 melanoma cells (EC50 < 10 nM). UV–vis and dynamic light-scattering measurements suggested that trans-bisglycoconjugated TFPP derivatives formed relatively large J-aggregates in an aqueous solution. trans-Bisglycoconjugated TFPP derivatives exhibited greater uptake by HeLa cells than those with different glycoconjugation patterns, with the exception of Zn(II) complexes. trans-Bisglycoconjugated TFPP derivatives efficiently generated hydrogen peroxide and hydroxyl radical by a type I photoreaction, while no significant differences were found in the efficiency of singlet oxygen generation by a type II photoreaction. These unique characteristics of trans-bisglycoconjugated TFPP derivatives support the conclusion that trans-bisglycoconjugation is a highly efficient and robust architecture for TFPP-based PDT development.

A simple method for anti-biofouling coating based on a star-like hyperbranched polymer having hydrophilic arms.

An amphiphilic hyperbranched polymer (HBP) containing both fluoroalkyl (Rf: −C6F13) pendants and oligo­(ethylene oxide) (nEO) parts was synthesized as a novel type of interfacial modifier to confer dynamic features on conventional polymer films. The HBP was always segregated at the outermost region of the polymer matrix in contact with air and water phases. The former and latter were driven by the presence of hydrophobic Rf pendants and hydrophilic nEO parts, respectively. Such a dynamic interface can be attained by changing the local conformation of HBP or segment-level segregation in the HBP molecule. In water, nEO parts formed a dissolved layer at the interface and induced excellent bioinert properties. Our strategy based on stable segregation, which could be maintained even after changing the environment, should be useful for constructing functional surfaces.