Zirconium oxide aerogel for effective enrichment of phosphopeptides with high binding capacity

Abstract

In this study, zirconium oxide (ZrO 2 ) aerogel was synthesized via a green sol-gel approach, with zirconium oxychloride, instead of the commonly used alkoxide with high toxicity, as the precursor. With such material, phosphopeptides from the digests of 4 pmol of β-casein with the coexistence of 100 times (mol ratio) BSA could be selectively captured, and identified by MALDI-TOF MS. Due to the large surface area (416.0 m 2 g −1 ) and the mesoporous structure (the average pore size of 10.2 nm) of ZrO 2 aerogel, a 20-fold higher loading capacity for phosphopeptide, YKVPQLEIVPN[pS]AEER (MW 1952.12), was obtained compared to that of commercial ZrO 2 microspheres (341.5 vs. 17.87 mg g −1 ). The metal oxide aerogel was further applied in the enrichment of phosphopeptides from 100 ng nonfat milk, and 17 phosphopeptides were positively identified, with a 1.5-fold improvement in phosphopeptide detection compared with previously reported results. These results demonstrate that ZrO 2 aerogel can be a powerful enrichment material for phosphoproteome study.

Mesoporous TiO2 aerogel for selective enrichment of phosphopeptides in rat liver mitochondria

“…3C). The specificity of the TiO 2 aerogel for phosphopeptide isolation is much better than that of ZrO 2 aerogel (with only three phosphopeptides identified) [32].…”

“…Recently, we proposed a simple strategy to prepare mesoporous ZrO 2 aerogel [32] with surface area up to 416.0 m 2 g −1 . The ZrO 2 aerogel was successfully applied to phosphopeptide capture from standard proteins and milk digests.…”

Zirconium(IV)-IMAC for phosphopeptide enrichment in phosphoproteomics

“…A year later, Feng et al published the first off-line Zr-IMAC method for p-pep LC-MS/MS analysis [26]. Since then, Zirconium has been utilised in different formats, such as magnetic core silica nanoparticles [43], monolith columns [44], zirconium arsenate-based materials [35,45] and aerogels [46]. Studies of Zr based techniques focused on ZrO2 and their performance were usually compared to TiO2 [37,[47][48][49].…”

Recent advances in enrichment and separation strategies for mass spectrometry‐based phosphoproteomics

“…For example, TiO 2 and iron oxide were coated onto a monolithic capillary column to enrich phosphopeptides from casein or human serum . Additionally, mesoporous TiO 2 and ZrO 2 aerogels were recently designed for selective enrichment of phosphopeptides in rat liver mitochondrion , where the binding capacity of mesoporous TiO 2 aerogel was shown to be six times higher than that of conventional TiO 2 microparticles for a single phosphopeptide standard. A total of 216 phosphoprotein groups were identified by the mesoporous TiO 2 aerogel from rat liver mitochondrion compared to less than 150 phosphoprotein groups identified by TiO 2 nanoparticles or microparticles .…”