A Comparison of Various Chips Used for the Manufacture of Biosensors Applied in Non-Fluidic Array SPRi, Based on the Example of Determination of Cathepsin D

Abstract

Non-fluidic array SPR imaging (SPRi) with appropriate biosensors is a new tool for the determination of various biomarkers in body fluids. Numerous biomarkers can be determined without signal enhancement or preliminarily preconcentration. The introduction of a new material solution of the chip may increase the scope of the application of this technique. Solutions with adhesive separating foil and an Ag/Au chip were compared with the previously used two-paint separating polymer and pure gold chip. These solutions were tested using the example of a biosensor for cathepsin D (Cath D), which consisted of pepstatin A (a Cath D inhibitor) immobilized via a cysteamine linker using the NHS/EDC protocol. Four material versions of the Cath D biosensor proved adequate in terms of range of linearity, LOQ, precision and recovery. All four versions of the biosensor were used for the determination of Cath D in the blood serum patients with glioblastoma and control samples, producing very similar results and showing an elevated biomarker concentration in the case of cancer. Therefore, the problem of determining the correct level of Cath D in the serum of healthy individuals has been resolved, correcting literature data which ranged over three orders of magnitude.

Utilizing fab fragment‐conjugated surface plasmon resonance‐based biosensor for detection of SalmonellaEnteritidis

“…Due to its higher chemical stability and high performance, gold is often used as a plasmonic material in SPR systems and acts as a sensor platform. While we do not have any studies on production costs, there is existing research in the literature suggesting the combined use of Au and Ag metals as a cost‐saving measure 43 . The production of gold‐coated sensor chips was carried out by evaporation of titanium onto glass slides.…”

“…While we do not have any studies on production costs, there is existing research in the literature suggesting the combined use of Au and Ag metals as a costsaving measure. 43 The production of gold-coated sensor chips was carried out by evaporation of titanium onto glass slides. Here, gold with 99.995% purity is plated on a titanium layer with the thickness of 47 nm.…”

Comparison of Fluidic and Non-Fluidic Surface Plasmon Resonance Biosensor Variants for Angular and Intensity Modulation Measurements

“…To create the non-fluidic biosensor, masks were used to determine the arrangement of measurement fields on its surface. These masks were crafted from a thin, single-sided polypropylene self-adhesive foil with a thickness of 20 μm, utilizing a punching method detailed in [ 13 ]. In brief, the number and spacing of the holes punched in the mask were controlled by a computer program that operated a numerically controlled device specially designed and manufactured for this purpose.…”

“…The Kretschmann configuration is a frequently employed setup in SPR systems, where a biosensor is created either on a prism coated with nanoscale metal, usually gold, or more commonly on a glass slide coated with nanoscale metal and affixed to the prism [1][2][3][4][5][6][7][8][9]. Due to differences in measurement environments, the SPR method has two variations: fluidic and non-fluidic [10][11][12][13][14][15]. The non-fluidic technique can be distinguished from the traditional fluidic SPR method in two ways: (1) the biosensor is formed ex situ, while in classic SPR it is formed in situ during measurement; (2) in non-fluidic SPR, the SPR measurement occurs after the removal of processing liquids, whereas in classic SPR, it takes place while processing liquids are present.…”