No abstract

Although computer simulation and cell culture experiments have shown that elongated spherical particles can be taken up into cells more efficiently than spherical particles, experimental investigation on effects of these different shapes over the particle-membrane association has never been reported. Therefore, whether the higher cellular uptake of an elongated spherical particles is a result of a better particle-membrane association as suggested by some calculation works or a consequence of its influence on other cellular trans-membrane components involved in particle translocation process, cannot be concluded. Here, we study the effect of particle shape on the particle-membrane interaction by monitoring the association between particles of various shapes and lipid bilayer membrane of artificial cell-sized liposomes. Among the three shaped lanthanide-doped NaYF4 particles, all with high shape purity and uniformity, similar crystal phase, and surface chemistry, the elongated spherical particle shows the highest level of membrane association, followed by the spherical particle with a similar radius, and the hexagonal prism-shaped particle, respectively. The free energy of membrane curvature calculated based on a membrane indentation induced by a particle association indicates that among the three particle shapes, the elongated spherical particle give the most stable membrane curvature. The elongated spherical particles show the highest cellular uptake into cytosol of human melanoma (A-375) and human liver carcinoma (HepG2) cells when observed through a confocal laser scanning fluorescence microscope. Quantitative study using flow cytometry also gives the same result. The elongated spherical particles also possess the highest cytotoxicity in A-375 and normal skin (WI-38) cell lines, comparing to the other two shaped particles.

No abstract

Here we show that the ability of oxidized carbon particles to penetrate phospholipid bilayer membrane varies with the particle shapes, chemical functionalities on the particle surface, lipid compositions of the membrane and pH conditions. Among the similar surface charged oxidized carbon particles of spherical (oxidized carbon nanosphere, OCS), tubular (oxidized carbon nanotube, OCT), and sheet (oxidized graphene sheet, OGSh) morphologies, OCS possesses the highest levels of adhesion to lipid bilayer membrane and penetration into the cell-sized liposome. OCS preferably binds better to the disordered lipid bilayer membrane (consisting of 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine) as compared to the ordered membrane (consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine and cholesterol). The process of OCS-induced leak on the membrane is pH responsive and most pronounced under an acidic condition. Covalently decorating the OCS's surface with poly(ethylene oxide) or (2-aminoethyl)trimethylammonium moieties decreases its ability to interact with the membrane. When used as carriers, OCSs can deliver curcumin into nucleus of A549 human lung cancer and human embryonic kidney cells, in contrast, curcumin molecules delivered by OCTs remain in the cytoplasm. OGShs cannot significantly enter cells and cannot induce noticeable cellular uptake of curcumin.

Effective anti-P. acnesusing near infrared light is made possible by perfecting the matching between absorption wavelengths of the loaded photosensitizer and emission wavelengths of the upconverting nanoparticles with high UVA/visible emissions.