Various nanocarriers for photosensitizers have been developed to solve the problems of limiting the clinical utility of photodynamic therapy (PDT); however, to date, no carriers capable of supplying oxygen have been reported. We reported the development of a novel system composed of red blood cell (RBC)-derived vesicles (RDVs) generated by osmotic stress and demonstrated the capacity of RDVs for encapsulating and delivering external cargo into targeted cells due to the cellular uptake of RDVs. In this study, protoporphyrin IX (PpIX)-encapsulated RDVs (PpIX@RDVs) were prepared by the hypotonic incorporation of PpIX into RDVs in an aqueous environment, characterized, and utilized for PDT of cancer. PpIX@RDVs were rapidly uptaken by tumor cells via endocytosis in vitro, and the highly phototoxic effect of PpIX@RDVs was demonstrated upon irradiation. Superoxide anion (O(2)˙) and singlet oxygen ((1)O(2)) were involved in PpIX@RDV-induced cell apoptosis and necrosis. Finally, we demonstrated that RDVs with an oxygen supply capacity have potential as versatile delivery vehicles for efficient PDT.
Spectral dependent values of the third-harmonic-generation susceptibility chi (3) (3omega:omega,omega,omega) of Ag-nanoparticles have been successfully determined. When the third-harmonic-generation wavelength coincides with the Ag-nanoparticlespsila plasmon-resonant frequency, strong chi (3) (3omega:omega,omega,omega) enhancement is experimentally proved for the first time.
Keratinocytes are important for epithelial antimicrobial barrier function. The activity of ion channels can affect the proliferation of keratinocytes. Little is known about Ca 2+ -activated K + currents in these cells. Ion currents in normal human oral keratinocytes were characterized with a patch-clamp technique. In whole-cell configuration, depolarizing pulses evoked K + outward currents ( I K ) in oral keratinocytes. Iberiotoxin (200 nM) and paxilline (1 μM) suppressed I K ; however, neither apamin (200 nM) nor 5-hydroxydecanoate (30 μM) had any effects on it. Caffeic acid phenethyl ester, a compound of honeybee propolis, increased I K with an EC 50 value of 12.8 ± 1.2 μM. In inside-out patches, a BK Ca channel was observed in keratinocytes, but not in oral squamous carcinoma (OCE-M1) cells. Caffeic acid phenethyl ester or cinnamyl-3,4-dihydroxy-α-cyanocinnamate applied to the intracellular surface of a detached patch increased BK Ca -channel activity. The results demonstrate that the properties of BK Ca channels in normal human oral keratinocytes are similar to those described in other types of cells. Caffeic acid derivatives can also stimulate BK Ca -channel activity directly.
We demonstrate molecular-specific third-harmonic-generation microscopy in cultured oral squamous cell carcinoma lines by using silver nano-particles as contrast agent. Through surface plasmon resonance enhancement, cancer cells are clearly identified with their molecular signature.
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