High-Affinity Capture of Proteins by Diamond Nanoparticles for Mass Spectrometric Analysis

Abstract

Carboxylated/oxidized diamond nanoparticles (nominal size 100 nm) exhibit exceptionally high affinity for proteins through both hydrophilic and hydrophobic forces. The affinity is so high that proteins in dilute solution can be easily captured by diamonds, simply separated by centrifugation, and directly analyzed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS). No preseparation of the adsorbed molecules from diamonds is required for the mass spectrometric analysis. Compared to conventional MALDI-TOF-MS, an enhancement in detection sensitivity by more than 2 orders of magnitude is achieved for dilute solution containing cytochrome c, myoglobin, and albumin because of preconcentration of the probed molecules. The lowest concentration detectable is 100 pM for a 1-mL solution. Aside from the enhanced sensitivity, the overall performance of this technique does not show any sign of deterioration for highly contaminated protein solutions, and furthermore, no significant peak broadening and band shift were observed in the mass spectra. The promise of this new method for clinical proteomics research is demonstrated with an application to human blood serum.

Nanocomposite and Nanostructured Carbon-based Films as Growth Substrates for Bone Cells

“…Nanocrystalline and multilayer diamond thin films were also used for coating the heads and cups of an artificial temporomanibular joint made of Ti6Al4V alloy (Papo et al, 2004). Another advantageous property of diamond and/or nanodiamond is its ability to bind various biological molecules, which can be utilized for sensing, detecting, separating and purifying these molecules (Bondar et al, 2004;Kong et al, 2005;Rezek et al, 2007). Nanocrystalline diamond (NCD) films used in our earlier studies also proved to be an impermeable coating preventing adverse effects of the underlying substrate on cell colonization.…”

Analysis of peptides and proteins affinity-bound to iron oxide nanoparticles by MALDI MS

“…Previously, C 18 functionalized silica nanoparticles have been utilized for hydrophobic interactions to extract peptides from acetonitrile, followed by liquid atmospheric pressure MALDI MS analysis [27]. Gold-modified magnetic nanoparticles [28] and diamond [29] were also used to selectively concentrate positively-charged proteins through electrostatic interaction. The adsorbed proteins were then eluted by adding MALDI matrix solution, such as sinapinic acid (SA) and ␣-cyano-4-hydroxycinnamic acid (CHCA).…”

Novel technologies for the discovery and quantitation of biomarkers of toxicity

“…This makes MALDI highly sensitive to small peptides, but reduces the range of peptide detection as compared to SELDI and results in some degree of interference from matrix ions (Chensong Pan 2006;Mazzatti et al 2007). Addition of ammonium salts or cetriamonium bromide (CTAB) to matrices has been shown to improve the resolution of MALDI spectra by reducing their sensitivity to salts and contaminants, as has addition of diamond nanoparticles to samples prior to matrix deposition (Kong et al 2005). Carbon nanotubes have been used as an inorganic matrix, eliminating interference issues associated with the matrix and allowing analytes to be well desorbed/ionized during analysis (Xu et al 2003), thus improving the quantitative reproducibility of the assay (Chensong Pan 2006).…”