Integrated optical waveguide-based fluorescent immunosensor for fast and sensitive detection of microcystin-LR in lakes: Optimization and Analysis

Abstract

Nowadays, biosensor technologies which can detect various contaminants in water quickly and cost-effectively are in great demand. Herein, we report an integrated channel waveguide-based fluorescent immunosensor with the ability to detect a maximum of 32 contaminants rapidly and simultaneously. In particular, we use waveguide tapers to improve the efficiency of excitation and collection of fluorescent signals in the presence of fluorophore photobleaching in a solid surface bioassay. Under the optimized waveguide geometry, this is the first demonstration of using such a type of waveguide immunosensor for the detection of microcystin-LR (MC-LR) in lake water. The waveguide chip was activated by (3-Mercaptopropyl) trimethoxysilane/N-(4-maleimidobutyryloxy) succinimide (MTS/GMBS) for immobilization of BSA-MC-LR conjugate, which was confirmed to have uniform monolayer distribution by atomic force microscopy. All real lake samples, even those containing MC-LR in the sub-microgram per liter range (e.g. 0.5 μg/L), could be determined by the immunosensor with recovery rates between 84% and 108%, confirming its application potential in the measurement of MC-LR in real water samples.

Active and Quantum Integrated Photonic Elements by Ion Exchange in Glass

“…Channel waveguides are the pillar of integrated optics [17][18][19]53,54] and optical integrated gratings are also fundamental for the implementation of many devices, including integrated amplifiers and lasers in rareearth doped glasses [19,55]. Directional couplers and 1 × N splitters, too, are based on channel waveguides and have been mainly intended for power derivation in optical fiber communication networks, but they also play an important role in optical sensing and in interferometry [31,56], including applications to optical astronomy [57]. The fabrication of these devices in a glass substrate usually requires a lithographic process [18,19] in order to allow a spatially selective ion-exchange.…”

“…A large amount of optical integrated sensors and biosensors based on ion-exchanged glass waveguides have been proposed [18][19][20]26] and keep being implemented in the last years [27][28][29][30]. An interesting example may be represented by a 32-analyte integrated optical fluorescence-based multi-channel sensor and its integration to an automated biosensing system [31]. Figure 5 shows the layout of the fiber-pigtailed sensing chip consisting of a single-mode channel waveguide circuit that distributes the light to 32 separate sensing patches on the chip surface.…”

“…Figure 5 shows the layout of the fiber-pigtailed sensing chip consisting of a single-mode channel waveguide circuit that distributes the light to 32 separate sensing patches on the chip surface. The use of this waveguide immunosensor, based on a K + -exchanged BK7 glass, was demonstrated for the detection of Microcystin-LR cyanotoxin in two real lake water samples taken from Fuhai lake and Beihai lake in Beijing [31].…”

Development of a Photoelectric Adjustment System With Extended Range for Fluorescence Immunochromatographic Assay Strip Readers

“…It is used for medical diagnosis, point of care testing, and laboratory work. The well-known applications include testings of food [2], [3], drugs [4], hormones [5], [6], virus [7], and environment [8], [9]. Much research so far has been conducted in developing high-performance FICA strip readers [10]- [13].…”

Optical Planar Waveguide Sensor with Integrated Digitally-Printed Light Coupling-in and Readout Elements

“…Interestingly, luminescent acrylate formulations have been applied through inkjet printing on polymeric waveguides generated on poly(methyl methacrylate) (PMMA) substrates by Bollgruen and coworkers to create remotely-addressable light sources that can couple light into flexible waveguides [26]. Moreover, regarding the sensing method, it is well known that the use of luminescence intensity measurements to perform magnitude readout advantageously leads to sensitivity improvement when there is no overlap between the exciting and emitted light spectra [27]. Even more, in a waveguide geometry, the light not absorbed in the readout element can be guided away from the detection region, further facilitating discrimination of the luminescence from the excitation light, leading to improved quality of the detectable signal.…”