Molecularly Imprinted Polymer-Coated Optical Waveguide for Attogram Sensing

Abstract

Ultrahigh sensitivity and selectivity are the ultimate goals of sensor development. For such purposes, we propose a sensing platform in which an optical fiber–waveguide–fiber (OFWF) structure is integrated with a molecularly imprinted polymer (MIP). The OFWF works as a highly efficient probe light launcher and signal light collector, and the MIP layer acts as a highly selective and sensitive sensing interface. In the MIP design, a high-molecular refractive index monomer (2-phenylphenoxyethyl acrylate) was copolymerized with a MIP functional monomer (acrylic acid). The resulting high-refractive index MIP layers could effectively extract the probe light from the waveguide and send it to the MIP sensing interface. Moreover, a highly elastic cross-linker (poly­(ethylene glycol) 600 diacrylate) was employed to increase the MIP mesh size, which could effectively increase the penetrability of the analyte. Rhodamine B (Rh B) is widely used in the textile industry, and its contamination may lead to serious public health problems. As a proof of concept, the Rh B chromophore was used as a molecular template, and the thin MIP layer was cured on the waveguide surface by utilizing the evanescent wave of the 405 nm propagating light in the waveguide. The MIP-OFWF sensing platform afforded highly selective monitoring of the absorption spectra of the components in a mixture solution of Rh B and methyl blue. It also afforded an extremely low detection limit of approximately 6.5 × 10–17 g/mL, with an absolute mass of 20–30 ag.

Surfactant-mediated enhanced FRET from a quantum-dot complex for ratiometric sensing of food colorants

“…Food colorants are extensively used as food additives to impart bright, particular, and stable colors to foodstuffs due to their more persistent nature than natural colouring agents and costeffectiveness. [1][2][3][4][5][6][7][8] This makes the commercial food stuff more attractive and appetizing for customers. The increasing use of food colorants induces a toxic and harmful threat to human health as well as to the environment.…”

“…The increasing use of food colorants induces a toxic and harmful threat to human health as well as to the environment. [1][2][3][4][5][6][7][8] Rhodamine B (RhB), a cationic xanthene group of organic dyes and carcinogenic agent, is commonly applied as a food colorant in commercial food products like chili powder, tomato ketchup, mixed fruit jam, sweets, syrups, candies and confectioneries. [1][2][3][4][5][6][7][8] The use of food colorants, mainly RhB, is severely restricted by the European Food Safety Authority (EFSA) and many other countries due to the health risks like hypothalamic cell apoptosis, oxidative stress in the uterus, skin and respiratory tract irritation and neurotoxicity.…”

“…[1][2][3][4][5][6][7][8] Rhodamine B (RhB), a cationic xanthene group of organic dyes and carcinogenic agent, is commonly applied as a food colorant in commercial food products like chili powder, tomato ketchup, mixed fruit jam, sweets, syrups, candies and confectioneries. [1][2][3][4][5][6][7][8] The use of food colorants, mainly RhB, is severely restricted by the European Food Safety Authority (EFSA) and many other countries due to the health risks like hypothalamic cell apoptosis, oxidative stress in the uterus, skin and respiratory tract irritation and neurotoxicity. [1][2][3][4][5][6][7][8] In line with the perilous nature and harmful effects of food colorants, the construction of a low-cost, environment-friendly and water-soluble optical nanoprobe is important for quantifying and identifying the presence of toxic food colorants in commercial food products.…”

“…[1][2][3][4][5][6][7][8] The use of food colorants, mainly RhB, is severely restricted by the European Food Safety Authority (EFSA) and many other countries due to the health risks like hypothalamic cell apoptosis, oxidative stress in the uterus, skin and respiratory tract irritation and neurotoxicity. [1][2][3][4][5][6][7][8] In line with the perilous nature and harmful effects of food colorants, the construction of a low-cost, environment-friendly and water-soluble optical nanoprobe is important for quantifying and identifying the presence of toxic food colorants in commercial food products. Meanwhile, the use of luminescent nanoprobes with the scope of analysing the sample via a sensitive, simpler and flexible method by using the spectrofluorimeter analytical technique is of paramount interest towards precise detection of food colorants.…”

Soft Optical Waveguides for Biomedical Applications, Wearable Devices, and Soft Robotics: A Review

“…[16][17][18][19] Soft optical waveguides not only exhibit a remarkable resistance to electromagnetic interference but also offer exceptional flexibility and durability. In particular, compared with chemically non-biocompatible soft materials, soft optical waveguides utilize biocompatible materials, such as hydrogels, naturally derived polymers and elastomers, [20][21][22][23][24][25][26] making them particularly suitable for long-term wear or implantable applications within the human body. Additionally, soft waveguides use light as a carrier of information and energy, enabling highly sensitive sensing and actuation in multiple dimensions (mechanical, thermal, biochemical, etc.…”