P.-H. Chung

Direct and in vitro observation of growth hormone receptor molecules in A549 human lung epithelial cells by nanodiamond labeling

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.

Size-dependent surface CO stretching frequency investigations on nanodiamond particles

In this work, the spectroscopic properties of surface functionalized nanodiamond particles are investigated via Fourier transform infrared spectroscopy. The functionalization of the nanodiamond surface was achieved chemically using strong acid treatment method. The size dependent C=O stretching frequency (between 1680 and 1820 cm(-1)) are studied for particle diameter sizes from the 5 to 500 nm range. The surface C=O stretching frequencies at approximately 1820 cm(-1), for large particle size (500 nm), down shifted to 1725 cm(-1) (5 nm) with decreasing particle sizes. We attributed the shift as a result of hydrogen bond formation between the COOH groups in the carboxylated nanodiamond surfaces. Particle size was characterized with dynamic light scattering method and surface morphology of the particles was investigated with scanning electron microscopy. The influence of pH value on C=O stretching frequency is also analyzed. This finding affords useful information for the studying of surface functionalized nanodiamonds with implications for their interaction with biomolecules.

The interaction of the protein lysozyme with bacteria E. coli observed using nanodiamond labelling

The application of a nanometre-sized diamond in Raman-detectable biolabelling is demonstrated in this study. The interaction of a lysozyme?nanodiamond complex with bacteria E. coli was observed via Raman mapping using the diamond Raman signal as the labelling marker. The results are compared with scanning electron microscope observations, and the adsorbed lysozymes functionality is analysed. High antibacterial activity of lysozyme?nanodiamond complex was observed, equivalent to active lysozyme in solution. The results suggest that nanodiamond labelling can be effective and that it can be applied in ambient conditions without complicated sample pre-treatments.

Observation of carbon-containing nanostructured mixed titania phases for visible-light photocatalysts

This research analyzed a visible-light-responsive carbon-containing titania photocatalysts prepared by sol-gel method using confocal Raman spectral mapping, transmission electron microscopy, and UV/visible spectroscopy. The incorporation of carbons in the initial titania powder of anatase and amorphous phases was found to facilitate the formation of rutile or brookite phases from the amorphous phase in the 150–250°C temperature range, resulting in nanostructured mixed titania phases which create interface states and effectively shift the band gap to ∼2.7eV. The further shift in the absorption tails up to 800nm was attributed to carbon species-covered and/or defected titania powders.

Surface-enhanced Raman spectroscopy of nanodiamond particles on silver

Surface-enhanced Raman scattering was applied to study the nanodiamond with particles’ sizes 100 and 5 nm, positioned on silver (Ag) substrate using high focused laser beam acceleration method. The nanodiamond particles suspended in distilled water were accelerated by a near infrared laser beam and attached to an Ag foil serving as the target. This allows the nanodiamond particles to be ordered, positioned, and to penetrate deep into Ag. The nanodiamond–Ag surface structure after nanoparticles∕laser beam treatment was analyzed using micro-Raman spectroscopy and scanning electron microscopy. Strong interaction between the nanodiamond and Ag surface can be achieved, which allows us to observe surface-enhanced Raman scattering (SERS). The most significant enhancement observed for carbon was trans-polyacetylene bands in addition to the D and G bands. The enhancement can achieve orders in magnitude both for 100 and 5 nm nanodiamonds. The selective enhancement of some composite band intensity, a characteristic ...

Antibacterial effect of ultrafine nanodiamond against gram-negative bacteria Escherichia coli

Abstract. We investigate the antibacterial effect of ultrafine nanodiamond particles with an average size of 5 nm against the gram-negative bacteria Escherichia coli (E. coli). UV-visible, Raman spectroscopy, and scanning electron microscopy (SEM) have been employed to elucidate the nature of the interaction. The influence on bacterial growth was monitored by measuring optical densities of E. coli at 600 nm as a function of time in the presence of carboxylated nanodiamond (cND) particles (100  μg/ml) in highly nutritious liquid Luria–Bertani medium. The SEM images prove that cND particles are attached to the bacterial cell wall surface and some portion of the bacterial cell wall undergoes destruction. Due to the change of the protein structure on the bacterial wall, a small Raman shift in the region of 1400 to 1700  cm−1 was observed when E. coli interacted with cNDs. Raman mapping images show strong evidence of cND attachment at the bacterial cell wall surface. Electrotransformation of E. coli with a fluorescent protein markers experiment demonstrated that the interaction mechanisms are different for E. coli treated with cND particles, E. coli by lysozyme treatment, and E. coli that suffer lysis.

Protein–Nanodiamond Complexes for Cellular Surgery

Nanodiamonds have attracted great attentions lately for their superb physical/chemical properties and promising bio/medical applications. This versatile material in its nanoscale exhibits little cytotoxicity in the cellular level and is considered to be most biocompatible among carbon derivatives. Its surface can be easily modified; so, various functional groups can be generated to allow conjugation of various biomolecules of interest for applications. Nanodiamonds thus provide a convenient platform for bio and medical applications. Among the various useful characteristics of nanodiamods, their spectroscopic properties, such as Raman and fluorescence, are ideal for use as a biocompatible marker to probe the biointeractions. In this chapter, the possibilities of using nanodiamond as a probe for biolabeling/cellular surgery are discussed. For this purpose, functionalization and characterization methods of nanodiamond surfaces are developed. The interaction of proteins with targeted bioobjects are investigated in various models to test the feasibility of ND to use as nano-bio-probe. Further applications using the developed nano-bio-probe as a surgical tool in the nano scale is also proposed. This developed methods of using nanodiamond as a nano-bio-probe will provide a biocompatible biolabel in bio and medical applications.