Raman cell imaging with boron cluster molecules conjugated with biomolecules.

Raman spectroscopic measurements and theoretical calculation revealed that the Raman bands corresponding to the B-H stretching vibrations of two types of simple icosahedral boron clusters, -carborane 3 and -dodecaborate 4 appeared at approximately 2450-2700 cm, and did not overlap with those of cellular components. Although -carborane 3 possesses a possible property as a Raman probe, it was difficult to measure Raman imaging in the cell due to its poor water solubility. In fact, -carborane derivative 6, which internally has an alkyne moiety, exhibited very weak Raman signals of the C[triple bond, length as m-dash]C stretching and the B-H stretching vibrations were barely detected at a 400 ppm boron concentration in HeLa cells.

Surface force and vibrational spectroscopic analyses of interfacial water molecules in the vicinity of methoxy-tri(ethylene glycol)-terminated monolayers: mechanisms underlying the effect of lateral packing density on bioinertness.

Unequivocal dependence of bioinertness of self-assembled monolayers of methoxy-tri(ethylene glycol)-terminated alkanethiol (EG3-OMe SAMs) on their packing density has been a mystery for more than two decades. We tackled this long-standing question by performing surface force and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements. Our surface force measurements revealed a physical barrier of interfacial water in the vicinity of the Au-supported EG3-OMe SAM (low packing density), whereas the Ag-supported one (high packing density) did not possess such interfacial water.