Search

Nanodiamond (ND) is surrounded by layers of graphite on its surface. This unique structure feature creates unusual fluorescence spectra, which can be used as an indicator to monitor its surface modification. Meanwhile, the impurity, nitroso (CNO) inside the ND can be photolyzed by two-photon absorption, releasing NO to facilitate the formation of a sp3 diamond structure in the core of ND and transforming it into a sp2 graphite structure. Such a conformational transition enlarges the size of ND from 8to90nm, resulting in a popcornlike structure. This transition reaction may be useful as nanoknives in biomedical application.

This letter presents direct observation of growth hormone receptor in one single cancer cell using nanodiamond-growth hormone complex as a specific probe. The interaction of surface growth hormone receptor of A549 human lung epithelial cells with growth hormone was observed using nanodiamond’s unique spectroscopic signal via confocal Raman mapping. The growth hormone molecules were covalent conjugated to 100nm diameter carboxylated nanodiamonds, which can be recognized specifically by the growth hormone receptors of A549 cell. The Raman spectroscopic signal of diamond provides direct and in vitro observation of growth hormone receptors in physiology condition in a single cell level.