Serum tumor marker detection on PEGylated lipid membrane using biosensor based on total internal reflection imaging ellipsometry

Abstract

a b s t r a c tWe describe highly sensitive, label-free, real time detection of the biomarker CA19-9 using microarray biosensors based on total internal reflection imaging ellipsometry (TIRIE), in which anti-CA19-9 is immobilized onto the PEGylated phospholipid membrane. Strong resistance against non-specific adsorption of PEGylated lipid membrane allows direct serum assay without the blocking agent. We find that PEG density has an influence on antibody assembly and only a proper amount of PEG is appropriate for antigen binding. Two different methods for antibody assembly are compared and finally protein A is preferred due to its higher protein binding efficiency. The estimated detection limit of CA19-9 is 18.2 U/ml, which is lower than the cut-off value for normal level (37 U/ml). Regression analysis between the results of microarray biosensor and electrochemiluminescence immunoassay (ECLIA) suggests a high correlation (R = 0.989). The capability for real-time monitoring of tumor marker with high sensitivity and selectivity in clinically relevant samples opens up substantial possibilities for early cancer diagnosis and treatment.

Optical biosensors

“…The apparent equilibrium dissociation constants (avidity constants, 10–100 pM) were used as characterizing parameters of viral receptor profiles [ 28 ]. Microarray biosensors based on total internal reflection imaging ellipsometry for the detection of the serum tumour biomarker CA19-9 had an estimated detection limit of CA19-9 of 18.2 units · ml −1 , which is lower than the cut-off value for a normal level [ 29 ].…”

Effect of alkanethiol molecular structure on sensitivity of surface plasmon resonance sensor

“…DSU has a long straight alkyl chain and a succinimidyl group in the head group; it forms a highly oriented and concentrated monolayer on Au surfaces [27]. CEG 6 is widely used as a biochemical linker because of its ability to prevent nonspecific adsorption [28][29][30][31]. C 2 -NTA is of interest to researchers because of its well-defined molecular structure and interesting properties, such as low intrinsic viscosity and solubility higher than analogues linear molecules [32].…”

Optical and Electrochemical Combination Sensor with Poly‐Aniline Film Modified Gold Surface and Its Application for Dissolved Oxygen Detection

“…The sensitivity of the TIRIE is proved to be 10 times higher than that of the conventional surface plasma resonance (SPR) in principle [18]. TIRIE has been used to dynamically observe chemical and biochemical reactions on a solid surface and obtained several successful experiences [19][20][21]. Applying a gold film coated on a glass slide as the working electrode and the sensing surface, TIRIE and electrochemical systems can be combined to develop a novel sensor (EC-TIRIE) to detect a redox process.…”