Functionalized nanomaterial-based electrochemical sensors: A sensitive sensor platform

Abstract The present research describes the design of robust electrochemical sensors based on electro-responsive molecularly imprinted polymer nanoparticles (e-MIPs). The e-MIPs, tagged with a redox probe, combine both recognition and reporting functions. This system replaces enzyme-mediator pairs used in traditional biosensors. The analyte recognition process relies on the generic actuation phenomenon when the polymer conformation of e-MIPs is changing in response to the presence of the template analyte. The analyte concentration is measured using voltammetric methods. In an exemplification of this technology, electrochemical sensors were developed for the determination of concentrations of trypsin, glucose, paracetamol, C4-homoserine lactone, and THC. The present technology allows for the possibility of producing generic, inexpensive, and robust disposable sensors for clinical, environmental, and forensic applications.

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Lab-on-Microsphere—FRET-Based Multiplex Sensor Platform

Nanomaterials ◽

10.3390/nano11010109 ◽

2021 ◽

Vol 11 (1) ◽

pp. 109

Author(s):

Vera Kuznetsova ◽

Viktoria Osipova ◽

Anton Tkach ◽

Maksim Miropoltsev ◽

Danil Kurshanov ◽

...

Keyword(s):

Resonance Energy Transfer ◽

Resonance Energy ◽

Double Layers ◽

Polymer Microspheres ◽

Layer By Layer ◽

Time Resolved ◽

Layer Deposition ◽

Sensor Platform ◽

Decay Times ◽

Sensitive Sensor

Here we report on the development and investigation of a novel multiplex assay model based on polymer microspheres (PMS) encoded with ternary AIS/ZnS quantum dots (QDs). The system was prepared via layer-by-layer deposition technique. Our studies of Förster resonance energy transfer (FRET) between the QD-encoded microspheres and two different cyanine dyes have demonstrated that the QD photoluminescence (PL) quenching steadily increases with a decrease in the QD-dye distance. We have found that the sensitized dye PL intensity demonstrates a clear maximum at two double layers of polyelectrolytes between QDs and Dye molecules on the polymer microspheres. Time resolved PL measurements have shown that the PL lifetime decreases for the QDs and increases for the dyes due to FRET. The designed system makes it possible to record spectrally different bands of FRET-induced dye luminescence with different decay times and thereby allows for the multiplexing by wavelength and photoluminescence lifetimes of the dyes. We believe that PMS encoded with AIS/ZnS QDs have great potential for the development of new highly selective and sensitive sensor systems for multiplex analysis to detect cell lysates and body fluids’ representative biomarkers.

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Support-Material-Free Microfluidics on an Electrochemical Sensors Platform by Aerosol Jet Printing

Sensors ◽

10.3390/s19081842 ◽

2019 ◽

Vol 19 (8) ◽

pp. 1842 ◽

Cited By ~ 9

Author(s):

Nicolò Giuseppe Di Novo ◽

Edoardo Cantù ◽

Sarah Tonello ◽

Emilio Sardini ◽

Mauro Serpelloni

Keyword(s):

Electrochemical Sensors ◽

Printed Electronics ◽

Limit Of Detection ◽

Support Material ◽

Uv Curable ◽

Sensor Platform ◽

Relative Standard ◽

Wide Range ◽

Jet Printing ◽

Aerosol Jet Printing

Printed electronics have led to new possibilities in the detection and quantification of a wide range of molecules important for medical, biotechnological, and environmental fields. The integration with microfluidics is often adopted to avoid hand-deposition of little volumes of reagents and samples on miniaturized electrodes that strongly depend on operator’s skills. Here we report design, fabrication and test of an easy-to-use electrochemical sensor platform with microfluidics entirely realized with Aerosol Jet Printing (AJP). We printed a six-electrochemical-sensors platform with AJP and we explored the possibility to aerosol jet print directly on it a microfluidic structure without any support material. Thus, the sacrificial material removal and/or the assembly with sensors steps are avoided. The repeatability observed when printing both conductive and ultraviolet (UV)-curable polymer inks can be supported from the values of relative standard deviation of maximum 5% for thickness and 9% for line width. We designed the whole microfluidic platform to make the sample deposition (20 μL) independent from the operator. To validate the platform, we quantified glucose at different concentrations using a standard enzyme-mediated procedure. Both mediator and enzyme were directly aerosol jet printed on working electrodes (WEs), thus the proposed platform is entirely fabricated by AJP and ready to use. The chronoamperometric tests show limit of detection (LOD) = 2.4 mM and sensitivity = 2.2 ± 0.08 µA/mM confirming the effectiveness of mediator and enzyme directly aerosol jet printed to provide sensing in a clinically relevant range (3–10 mM). The average relative standard inter-platform deviation is about 8%. AJP technique can be used for fabricating a ready-to-use microfluidic device that does not need further processing after fabrication, but is promptly available for electrochemical sample analysis.

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