Reusable hydroxyapatite nanocrystal sensors for protein adsorption

Abstract

The repeatability of the adsorption and removal of fibrinogen and fetal bovine serum on hydroxyapatite (HAp) nanocrystal sensors was investigated by Fourier transform infrared (FTIR) spectroscopy and quartz crystal microbalance with dissipation (QCM-D) monitoring technique. The HAp nanocrystals were coated on a gold-coated quartz sensor by electrophoretic deposition. Proteins adsorbed on the HAp sensors were removed by (i) ammonia/hydrogen peroxide mixture (APM), (ii) ultraviolet light (UV), (iii) UV/APM, (iv) APM/UV and (v) sodium dodecyl sulfate (SDS) treatments. FTIR spectra of the reused surfaces revealed that the APM and SDS treatments left peptide fragments or the proteins adsorbed on the surfaces, whereas the other methods successfully removed the proteins. The QCM-D measurements indicated that in the removal treatments, fibrinogen was slowly adsorbed in the first cycle because of the change in surface wettability revealed by contact angle measurements. The SDS treatment was not effective in removing proteins. The APM or UV treatment decreased the frequency shifts for the reused HAp sensors. The UV/APM treatment did not induce the frequency shifts but decreased the dissipation shifts. Therefore, we conclude that the APM/UV treatment is the most useful method for reproducing protein adsorption behavior on HAp sensors.

Competitive adsorption of fibronectin and albumin on hydroxyapatite nanocrystals

“…• C by wet chemical method [33,43]. A dilute H 3 PO 4 solution was added dropwise into a Ca(OH) 2 suspension until reaching the pH of 8.0 to precipitate the nanocrystals.…”

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

“…Also, HA is added to some brands of toothpaste as a gentle polishing agent instead of calcium carbonate (Niwa et al 2001;Kim et al 2006). Non-biomedical applications of HA include its using as an environmentalfriendly filler for elastomers (Pietrasik et al 2008), a lowtemperature sorbent (Bailliez et al 2004;Corami et al 2008) and/or stabilizer (Wang et al 2014b) of poisonous chemical elements, a high-temperature sorbent for carbon dioxide (Landi et al 2014), both a catalyst Rodrigues et al 2014) and a carrier for other catalysts (Domínguez et al 2009;Sun et al 2009;Vukomanović et al 2012), a material for ultraviolet light protection (Holzmann et al 2009) and sunscreen filter (Piccirillo et al 2014), as well as a component of various sensors (Nagai et al 1988;Petrucelli et al 1996;Tagaya et al 2010;Khairnar et al 2011). Finally, highly flexible and nonflammable inorganic paper could be prepared from HA (Lu et al 2014a).…”

Block-copolymer-assisted synthesis of hydroxyapatite nanoparticles with high surface area and uniform size

“…Because its chemical and morphological properties are similar to those of bone and teeth, hydroxyapatite (HA, Ca 10 (PO 4 ) 6 (OH) 2 ) with a Ca : P ratio of 1.67 : 1 has attracted much attention as a new biomaterial for dental and orthopedic applications [1][2][3][4][5][6][7]. The mechanical strength of synthetic HA is one of the most important properties when using HA in load-bearing bone-grafting materials.…”