Single-Step Nanoplasmonic VEGF₁₆₅ Aptasensor for Early Cancer Diagnosis

Abstract

Early cancer diagnosis is very important for prevention or mitigation of metastasis. However, we must improve the diagnosis and assessment of cancer by an effective and efficient method. Here, we report a single-step detection method using nanoplasmonic aptamer sensor (aptasensor), targeting a vascular endothelial growth factor-165 (VEGF165), a predominant biomarker of cancer angiogenesis. Our single-step detection is accomplished by: (1) specific target recognition by an aptamer-target molecule interaction; (2) direct readouts of the target recognition. The readout is achieved by inactivation of surface plasmon enhancement of fluorescent probes preattached to the aptamers. Our aptasensor provides the appropriate sensitivity for clinical diagnostics with a wide range of linear detection from 25 pg/mL to 25 µg/mL (= from 1.25 pM to1.25 µM), high specificity for VEGF165 against PDGF-BB, osteopontin (OPN), VEGF121, and NaCl, and temporal/thermal/biological stability. In experiments with 100 % serum and saliva from clinical samples, readouts of the aptasensor and an ELISA for VEGF165 show good agreement within the limit of the ELISA kit. We envision that our developed aptasensor holds utility for point-of-care cancer prognostics by incorporating simplicity in detection, low-cost for test, and required small sample volume.

G-quadruplex DNAzyme-based electrochemiluminescence biosensing strategy for VEGF165 detection: Combination of aptamer–target recognition and T7 exonuclease-assisted cycling signal amplification

“…As shown in the inset in Fig. 4, a broad linear relationship between the differences in the ECL intensity and the logarithm of concentration of VEGF 165 in the range of 1 pM to 20 nM with a correlation coefficient (R) of 0.996, and the linear fitting equation is ΔI¼882.14-1432.2 lg [c], where ΔI is I 0 À I, c is the concentration of VEGF 165 ; this range was wider than those in previous reports (Zhao et al, 2012;Freeman et al, 2012;Kopra et al, 2014;Mita et al, 2014;Cho et al, 2012;Chen et al, 2014). Detection limit was experimentally estimated to be 0.2 pM, which was lower than that in fluorescence (Freeman et al, 2012;Kopra et al, 2014) and electrochemical method (Nonaka et al, 2012) (the detailed comparison of the analytical performance for VEGF 165 detection by using our strategy and those reported in the literature is summarized in Table 1).…”

Ultrasensitive SERS detection of VEGF based on a self-assembled Ag ornamented–AU pyramid superstructure

“…Other analytical platforms proposed for the quantification of VEGF include electrical detection of VEGF using Si nanowire field effect transistors (Lee et al, 2009), rolling circle amplification (Cheng et al, 2010a(Cheng et al, , 2010bSuzuki and Yokoyama, 2011), enhanced resonance light scattering (Chen et al 2012), aptasensor based on fluorescence polarization , fluorescent peptide conjugated nanopillar chip (Suzuki and Yokoyama, 2011), porosity induced hydrogel microspheres (Mohammad Al-Ameen, 2013) and optical and electrochemical sensors based on an aptasensor (Abe et al, 2012;Cho et al, 2012;Freeman et al, 2012). However, expensive instrumentation is involved in these methods.…”

Nanoplasmonic biosensors: current perspectives

“…A colloidal GNP-based nanoplasmonic aptamer sensor (aptasensor) (Figure 1) was developed for the detection of vascular endothelial growth factor-165 (VEGF 165), biomarker of cancer angiogenesis. 21 Aptamer developed toward VEGF 165, and labeled with Cy3B, was electrostatically bound to a positively charged poly-l-lysine (PLL)-coated GNP surface. This conjugate exhibited surface-enhanced fluorescence (SEF) because of the metal interaction increasing the radiative fluorescent decay rate of Cy3B.…”