Lossy Mode Resonance Based Microfluidic Platform Developed on Planar Waveguide for Biosensing Applications

Abstract

The development of resonance phenomena-based optical biosensors has gained relevance in recent years due to the excellent optical fiber properties and progress in the research on materials and techniques that allow resonance generation. However, for lossy mode resonance (LMR)-based sensors, the optical fiber presents disadvantages, such as the need for splicing the sensor head and the complex polarization control. To avoid these issues, planar waveguides such as coverslips are easier to handle, cost-effective, and more robust structures. In this work, a microfluidic LMR-based planar waveguide platform was proposed, and its use for biosensing applications was evaluated by detecting anti-immunoglobulin G (anti-IgG). In order to generate the wavelength resonance, the sensor surface was coated with a titanium dioxide (TiO2) thin-film. IgG antibodies were immobilized by covalent binding, and the detection assay was carried out by injecting anti-IgG in PBS buffer solutions from 5 to 20 μg/mL. The LMR wavelength shifted to higher values when increasing the analyte concentration, which means that the proposed system was able to detect the IgG/anti-IgG binding. The calibration curve was built from the experimental data obtained in three repetitions of the assay. In this way, a prototype of an LMR-based biosensing microfluidic platform developed on planar substrates was obtained for the first time.

Soft molecularly imprinted nanoparticles with simultaneous lossy mode and surface plasmon multi-resonances for femtomolar sensing of serum transferrin protein

“…It was reported in the literature that the characteristics of LMR resonance are strongly determined by the nanometric film deposited on the sensing area. Any change in the nanocoating parameters affect the characteristics of LMR, due to the effective RI resulting from the modified coupled modes 34 , 35 .

Figure 2 Resonance wavelength analysis of nanoMIP’s functionalized probes with water-glycerine solutions.

…”

“…Concerning the changes in the LMR resonance upon HTR binding, these were observed to red-shift. It was expected that the functionalization of the gold-coated metal oxide bilayers with the nanoMIPs, modifies the interface layer characteristics, affecting the LMR resonance behavior 34 , 35 . In the present case, the LMR shifts observed at binding were opposite to the SPR.…”

4-(Triethoxysilyl)butanoic acid as a self-assembled monolayer for surface modification of titanium dioxide

“…The lossy mode resonance planar waveguide biosensor using an Eudragit L100 immobilized capture antibody was used to detect anti-rabbit IgG and the LOD was 2.2 μg mL −1 . 27 The TiO 2 -coated porous silicon biosensor using protein A to immobilize the capture antibody by physical adsorption was used to detect sheep IgG and the LOD was 0.6 μg mL −1 . 28 The exfoliated flexible photonic crystal slabs were able to detect the cat IgG of 38 to 56 μg mL −1 , and APTES, PDITC and DMF sequentially used to modify the TiO 2 surface, and protein A was used to immobilize the capture antibody.…”

Lossy Mode Resonance-Based Sensors in Planar Configuration: A Review

“…In addition, Fig. 5c shows the sensorgram corresponding to a biosensor for detection of anti-IgGs with a limit of detection of 2.2 μg/mL and a range of concentrations analyzed from 5 μg/mL and 20 μg/mL [45].…”