ABSTRACT
BACKGROUND: We have developed a method, termed laser-activated nano-thermolysis as a cell elimination technology (LANTCET), for the selective detection and destruction of individual tumor cells by the generation of intracellular photothermal bubbles around clusters of gold nanoparticles. METHOD: Bare nanoparticles and their conjugates to C225 tumor-specific monoclonal antibodies were applied in vitro to C225-positive squamous carcinoma cells and in vivo to an experimental tumor in a rat in order to form intracellular clusters of nanoparticles. RESULTS: Single 10 ns laser pulses generated intracellular photothermal microbubbles at a near-infrared and visible wavelengths. The cells with the clusters yielded an almost 100-fold decrease in the laser fluence threshold for bubble generation and cell damage relative to that for the cells without clusters. Cell damage had a mechanical origin and single cell selectivity. Three LANTCET processes (cell detection, damage and optical guidance) were realized as a microsecond sequence and with the one device.
Subject(s)
Carcinoma, Squamous Cell/metabolism , Gold/chemistry , Metal Nanoparticles/chemistry , Nanotechnology/methods , Animals , Cell Line, Tumor , Equipment Design , Humans , Lasers , Light , Nanostructures/chemistry , Neoplasm Transplantation , Optics and Photonics , Rats , Scattering, RadiationABSTRACT
Robust gold nanorod substrates were fabricated for refractive index sensing based on localized surface plasmon resonance (LSPR). The substrate sensitivity was 170 nm/RIU with a figure of merit of 1.3. To monitor biomolecular interactions, the nanorod surfaces were covered with a self-assembled monolayer and conjugated to antibodies by carbodiimide cross-linking. Interactions with a specific secondary antibody were monitored through shifts in the LSPR spectral extinction peak. The resulting binding rates and equilibrium constant were in good agreement with literature values for an antibody-antigen system. The nanorod LSPR sensors were also shown to be sensitive and specific. These results demonstrate that given a sufficiently stable nanoparticle substrate with a well defined chemical interface, LSPR sensing yields similar results to the surface plasmon resonance technique, yet with much simpler instrumentation.
