Near-infrared laser-triggered carbon nanohorns for selective elimination of microbes

Abstract

Carbon nanomaterials, such as carbon nanohorns and carbon nanotubes, have attracted considerable attention for their biomedical applications. We report here the first application of carbon nanohorns (CNHs) as potent laser therapeutic agents for highly selective elimination of microorganisms. This is the first report, supported by direct observations, of the highly selective elimination of yeast and bacteria (Saccharomyces cerevisiae and Escherichia coli) by employing molecular recognition element–CNH complexes and a near-infrared laser.

Photothermic regulation of gene expression triggered by laser-induced carbon nanohorns

“…The UV-vis-NIR optical absorption spectrum of PBS dispersions of BSA-CNH peaked at 260 nm (Fig. 1B), characteristic of the absorption of tubular graphite and BSA molecules (27,28,44). The BSA-CNH complexes were ∼100-200 nm in diameter as estimated by atomic force microscopy and dynamic light scattering analyses (SI Appendix, Fig.…”

“…S1 A and B). An aqueous CNH complex dispersion (CNH concentration, 100 μg/mL) exhibited a significant increase in temperature over time (26)(27)(28) under 670-nm laser irradiation and with an increase in laser power, whereas control dispersions without CNH complexes showed no increase in temperature at all laser powers (Fig. 1C).…”

“…1). Given the hydrophobic nature of CNHs (26)(27)(28), we complexed them with commercially available low-bioactive BSA molecules through low-power (80 W) facile ultrasonic treatment (Fig. 1A).…”

“…Nanocarbons, such as carbon nanotubes (CNTs) and carbon nanohorn (CNH), are considered useful in science and technology because of their remarkable physical and chemical properties, some of which might help overcome the limitations of traditional laser light technologies. In particular, nanocarbons have extraordinary photothermal energy conversion efficiency and high absorption cross-sections in a wavelength range capable of transmission within the diagnostic window (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38). Although gold nanoparticles also have such photothermal properties, nanocarbons can be more effectively heated at various wavelengths because of their strong absorbance over a wide range of the optical region (38).…”

Carbon Nanotube–Polymer Composite for Light‐Driven Microthermal Control

“…[10] Recently, we [20,21] and other researchers [5,6] demonstrated that photoinduced nanocarbons, such as carbon nanohorns and CNTs, can operate as exothermic nanomaterials. We prepared an SWNT hybrid microchip to investigate the photoinduced exothermic properties of the PL-BSA-SWNT-PDMS composite (see Figure 3 a, b and the Supporting Information for details).…”