Bloch surface wave enhanced biosensor for the direct detection of Angiopoietin-2 tumor biomarker in human plasma

Abstract

Quantitative detection of angiogenic biomarkers provides a powerful tool to diagnose cancers in early stages and to follow its progression during therapy. Conventional tests require trained personnel, dedicated laboratory equipment and are generally time-consuming. Herein, we propose our developed biosensing platform as a useful tool for a rapid determination of Angiopoietin-2 biomarker directly from patient plasma within 30 minutes, without any sample preparation or dilution. Bloch surface waves supported by one dimensional photonic crystal are exploited to enhance and redirect the fluorescence arising from a sandwich immunoassay that involves Angiopoietin-2. The sensing units consist of disposable and low-cost plastic biochips coated with the photonic crystal. The biosensing platform is demonstrated to detect Angiopoietin-2 in plasma samples at the clinically relevant concentration of 6 ng/mL, with an estimated limit of detection of approximately 1 ng/mL. This is the first Bloch surface wave based assay capable of detecting relevant concentrations of an angiogenic factor in plasma samples. The results obtained by the developed biosensing platform are in close agreement with enzyme-linked immunosorbent assays, demonstrating a good accuracy, and their repeatability showed acceptable relative variations.

Hybrid inorganic/organic photonic crystal biochips for cancer biomarkers detection

“…Such a plot can be used to retrieve an estimation of the fluorescence LoD, by extrapolating the linear dependency down to the level corresponding to three times the standard deviation of the measurement at lowest c. We find that the fluorescence LoD is 6 ng/ml. Again such a value can be compared to that obtained with the same biochips and APTES chemistry and without PtG, which is 0.65 ng/ml for the same Ang2 biomarker [21].…”

Novel Photonic Bio-Chip Sensor Based on Strained Graphene Sheets for Blood Cell Sorting

“…In between, due to their valuable features, such as fast real-time responses and remarkable sensitivities, transducers, based on surface waves have received more attention for such applications [2][3][4][5][6][7]. Sensors based on the plasmon resonances and Bloch surface waves (BSW) are the two most commonly considered ones at present [5][6][7][8][9][10][11]. In other words, as excitation/suppression of these waves is seriously sensitive to any small perturbation in the surrounding environment; they can easily reflect the characteristics of the existing ingredients in contact with the sensor, i.e., as each bio-agent has specific optical features, its coupling to a surface wave next to it would be different.…”

“…Surface plasmon resonances (SPRs) are usually excited at the interface of metal-dielectric or metal-analyte layers [6][7][8][9]. However, now it has been well proven that the sensors based on SPR modes face numerous challenges, including difficulties in excitations of resonant modes and their short-term stabilities, having significant absorption losses, and thus, low sensitivity and complexities in the fabrication process, as well as optimum working for a limited extent of bio-agents [6][7][8][9][10][11]. As result, photonic crystals (PCs), under Kretschmann/Otto configurations that monitor alterations of the excited BSW modes, are undoubtedly more discussed at present [11][12][13].…”

Inverse Photonic Design of Functional Elements That Focus Bloch Surface Waves

“…The propagation lengths, in the limit of vanishing intrinsic material absorption and the absence of scattering losses, ultimately are only limited by the number of layers in the PC. Such appealing characteristics make BSWs suitable for many sensing applications [13][14][15] and also for enhancing the interaction with a magnetic optical field 5 and supporting organic polaritons that result from the strong coupling between a BSW and organic excitons 16 .…”