Mass Spectrometric Determination of the Effect of Surface Deactivation on Membranes Used for In-Situ Sampling of Cerebrospinal Fluid (CSF)

Abstract

In this paper, a strategy for structured monitoring of surface modifications to control protein adsorption to membrane structures is presented. The already established on-surface enzymatic digestion (oSED) method combined with nano-liquid chromatography and tandem mass spectrometry (LC-MS/MS) analysis was employed for the analysis of proteins in ventricular cerebrospinal fluid (vCSF) from neurointensive care patients. Protein adsorption was studied by in-situ sampling in a temporally resolved manner on both immobilized native and Pluronic-deactivated membranes. Deactivation was significantly reducing the protein adsorption but it also induced novel selective properties of the surface. The proposed versatile strategy will facilitate protein-biomaterial, protein-polymer, protein-protein interaction studies in the future.

Mechanistic investigation of the on-surface enzymatic digestion (oSED) protein adsorption detection method using targeted mass spectrometry

“…[2][3][4][5][6] The problem with protein adsorption has been observed in these studies and surface deactivation has been used to reduce the binding of proteins to the biomaterial surface. 7,8 There are several methods used for the investigation of the adsorption layer of proteins, e.g. surface plasmon resonance (SPR) 9,10 and attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy.…”

“…Recently, several approaches using mass spectrometry (MS) for the characterization of adsorbed proteins on biomaterial surfaces have been reported. [6][7][8] The idea was to use a method wherein on-surface enzymatic digestion (oSED) of proteins is performed. The extracted peptides are further characterized by liquid chromatography (LC) coupled to tandem MS detection (LC-MS/MS) to provide identification of the adsorbed proteins.…”

“…The oSED method has been used for surface characterization studies in experiments wherein a static liquid surrounds a membrane with adsorbed proteins. [6][7][8] Reagents for the reduction of disulfide bonds and the alkylation of the cysteines to prevent the reversed reaction, dithiothreitol (DTT) and iodoacetamide (IAA), were added and incubation was performed similarly to in-solution digestion. Thereafter, trypsin was added and the proteins were enzymatically cleaved into peptides.…”