Identification and Affinity-Quantification of ß-Amyloid and α-Synuclein Polypeptides Using On-Line SAW-Biosensor-Mass Spectrometry

Abstract

Abstract. Bioaffinity analysis using a variety of biosensors has become an established tool for detection and quantification of biomolecular interactions.Biosensors, however, are generally limited by the lack of chemical structure information of affinity-bound ligands. On-line bioaffinity-mass spectrometry using a surface-acoustic wave biosensor (SAW-MS) is a new combination providing the simultaneous affinity detection, quantification, and mass spectrometric structural ({"' characterization of ligands. We describe here an on-line SAW-MS combination for direct identification and affinity determination, using a new interface for MS of the affinity-isolated ligand eluate. Key element of the SAW-MS combination is a microfluidic interface that integrates affinity-isolation on a gold chip, in-situ sample concentration, and desalting with a microcolumn forMS of the ligand eluate from the biosensor. Suitable MSacquisition software has been developed that provides coupling of the SAW-MS interface to a Bruker Daltonics ion trap-MS, FTICR-MS, and Waters Synapt-QTOF-MS systems. Applications are presented for mass spectrometric identifications and affinity (K 0 ) determinations of the neurodegenerative polypeptides, r..-amyloid (AI1), and pathophysiological and physiological synucleins (a-and r..-synucleins), two key polypeptide systems for Alzheimer's disease and Parkinson's disease, respectively. Moreover, first in vivo applications of aSyn polypeptides from brain homogenate show the feasibility of on-line affinity-MS to the direct analysis of biological material. These results demonstrate on-line SAW-bioaffinity-MS as a powerful tool for structural and quantitative analysis of biopolymer interactions.

Specific expression pattern of tissue cytokines analyzed through the Surface Acoustic Wave technique is associated with age-related spontaneous benign prostatic hyperplasia in rats

“…This device consists of a biosensor unit, an auto-sampler and a microchip module with a gold layer sensing surface on a quartz chip. The chip surface was coated with dextran and functionalized with a flat 16-mercaptohexadecanoic acid self-assembled monolayer (COOH-SAM), as previously described [56] .…”

“…In this sense, the search of a feasible technique that could be applicable to the diagnostic of prostate alterations was centered on the Surface Acoustic Wave (SAW) technique. In fact, the SAW technique has been already applied to optimize diagnosis and even to develop potential new therapeutically approaches in processes such Alzheimer's disease, Parkinson's disease and epidermal growth factor-linked tumors [40] , [41] , [42] , [43] , [44] . The main reason for the application of the SAW technique in diagnosis/prognosis is centered in the fact that SAW is a very powerful tool for label-free detection of a broad range of numerous analytes, from small molecules, peptides, proteins and lipid membranes to whole cells and cell cultures.…”

Peptides Targeting EGF Block the EGF–EGFR Interaction

“…Immobilisation of EGF was performed by covalent binding of af lat 16-mercaptohexadecanoic acid self-assembled monolayer (COOH-SAM), as previously described. [34] EGF was immobilised on the SAM by carboxyl group activation with…”

Sample Clean‐up Strategies for ESI Mass Spectrometry Applications in Bottom‐up Proteomics: Trends from 2012 to 2016

“…Slamnoiu et al. developed a microfluidic interface that combined affinity isolation on a gold chip, in situ sample concentration, and a C 18 guard microcolumn for desalting. The method was applied for the direct identification and affinity determination of the neurodegenerative polypeptides β‐amyloid (Aβ), and pathophysiological and physiological synucleins (α‐ and β‐synucleins), two key polypeptide systems for Alzheimer's disease and Parkinson's disease, respectively, prior to an on‐line surface‐acoustic wave biosensor –MS.…”