SERS-based quantitative detection of ovarian cancer prognostic factor haptoglobin

Abstract

Surface-enhanced Raman spectroscopy (SERS) is increasingly being used for biosensing because of its high sensitivity and low detection limit, which are made possible by the unique Raman ‘fingerprint’ spectra from the biomolecules. Here we propose a novel SERS method for the fast, sensitive, and reliable quantitative analysis of haptoglobin (Hp), an acute phase plasma glycoprotein that is widely gaining application as a prognostic ovarian cancer biomarker. We exploited the peroxidase activity of the hemoglobin–haptoglobin (Hb–Hp) complex formed by the selective and specific binding of Hp to free Hb to catalyze the reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) substrate and hydrogen peroxide to result in the final product of strongly SERS-active TMB 2+ . We observed a linear increase in the SERS signal of TMB 2+ with increasing concentrations of Hb–Hp complex from 50 nM to 34 μM. Based on this concentration-dependent SERS spectrum, we quantified Hp in clinical samples. We observed that our inference about the prognosis of the disease coincided with the histology data and that our method was much more sensitive than the enzyme-linked immunosorbent assay method.

Retinoic acid is abundantly detected in different depots of adipose tissue by SERS

“…We then selected 3,3',5,5'-tetramethylbenzidine (TMB) as the ideal substrate for our study due to its unique property, less toxicity and more sensitivity compared to commonly used peroxidase reactants. 18,19 Hence, TMB was used as peroxidase substrate for detection and quantification of RA. Figure 2A shows the peroxidase reaction of TMB to TMB 2C using HRP conjugate in presence of H 2 O 2 .…”

“…The product SERS spectra show specific Raman bands at 1191, 1337, and 1605 cm ¡1 that is characteristic of TMB 2C . 14,19 The intensity of the specific Raman band corresponding to 1605 cm ¡1 wavenumber was selected as the peak of interest as its intensity is inversely proportional to the concentration of RA present in the sample (Fig. 2C).…”

“…14,19 Briefly we used 633 nm excitation laser with 10% laser power, 1800 line/mm grating along with cooled CCD. For sample focusing we used 20X objective lens with N.A 0.4.…”

Early biomarker discovery in urine of Walker 256 subcutaneous rat model

“…The expression trends of these corresponding proteins were consistent with the results from label-free quantification. [11], lung [12], colorectal [13], ovarian [14], rectal [15], gastric [16] Urine, blood, saliva, BALF P07151 P61769 Beta-2-microglobulin (B2MG) Yes Colon [17], Ovarian [18], prostate [19] Urine, blood…”

Development of highly reliable SERS‐active photonic crystal fiber probe and its application in the detection of ovarian cancer biomarker in cyst fluid

“…However, quantity of Hp can increase after a trauma or during an infection or an inflammation. Studies have demonstrated that Hp concentration in patient's serum and fluid within the ovarian cyst is strongly correlated to ovarian cancer . Usual methods of detection for ovarian cancer biomarker, which include enzyme‐linked immunosorbent assay, electrochemical impedance spectroscopy, and chromogen staining are primarily time‐consuming and quite tedious to perform .…”