Abstract
BackgroundSince vascular endothelial growth factor (VEGF) is a significant regulator of cancer angiogenesis, it is essential to develop a technology for its sensitive detection. Herein, we sensitized a chemiluminescence (CL) immunoassay through the combination of H2O2-sensitive TGA-CdTe quantum dot (QD) as signal transduction, dextran as a cross-linker to prepare enzyme-labeled antigen and the ultrahigh bioactivity of catalase (CAT) as reporter enzyme.ResultsUnder the optimized experimental conditions, the chemiluminescence enzyme-linked immunosorbent assay (CL-ELISA) method can detect VEGF in the excellent linear range of 2–35,000 pg mL−1, with a detection limit (S/N = 3) of 0.5 pg mL−1 which was approximately ten times lower than the commercial colorimetric immunoassay. This proposed method has been successfully applied to the clinical determination of VEGF in the human serum samples, and the results illustrated an excellent correlation with the conventional ELISA method (R2 = 0.997). The suitable recovery rate of the method in the serum ranged from 97 to 107%, with a relative standard deviation of 1.2% to 13.4%.ConclusionsThe novel immunoassay proposes a highly sensitive, specific, and stable method for very low levels detection of VEGF that can be used in the primary diagnosis of tumors. With the well-designed sensing platform, this approach has a broad potential to be applied for quantitative analysis of numerous disease-related protein biomarkers for which antibodies are available.
Highlights
Since vascular endothelial growth factor (VEGF) is a significant regulator of cancer angiogenesis, it is essential to develop a technology for its sensitive detection
We have recently developed a catalase assay method based on the finding that the CL of the TGA-CdTe/H2O2 system is reduced owing to the consumption of H2O2 by the catalytic action of CAT [56]
We concluded that our TGA-CdTe quantum dot (QD) exhibit uniform size distribution and excellent optical properties
Summary
Since vascular endothelial growth factor (VEGF) is a significant regulator of cancer angiogenesis, it is essential to develop a technology for its sensitive detection. Vascular endothelial growth factor (VEGF) is a significant regulator of both pathologic and physiologic angiogenesis by activating VEGFreceptor tyrosine kinases in all endothelial cells [4,5,6,7]. VEGF is a signaling protein that has been applied as an Ghavamipour et al J Nanobiotechnol (2020) 18:93 progression and survival in patients with malignant melanoma [18]. The VEGF level in healthy people is usually less than 100 pg mL−1 and clearly increased by the progression of the clinical stage (198 pg mL−1 in stage I–II; 955 pg mL−1 in stage III–IV) in ovarian cancer [19]. Overexpressed VEGF values were previously reported in patients with brain tumors [20]. VEGF serum level has important effects as a biomarker on some diseases and subsequent monitoring of treatment
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