Polyaniline-Based Photothermal Paper Sensor for Sensitive and Selective Detection of 2,4,6-Trinitrotoluene

Paper-based sensors and assays: a success of the engineering design and the convergence of knowledge areas

This review shows the recent advances and state of the art in paper-based analytical devices (PADs) through the analysis of their integration with microfluidics and LOC micro- and nanotechnologies, electrochemical/optical detection and electronic devices as the convergence of various knowledge areas. The important role of the paper design/architecture in the improvement of the performance of sensor devices is discussed. The discussion is fundamentally based on μPADs as the new generation of paper-based (bio)sensors. Data about the scientific publication ranking of PADs, illustrating their increase as an experimental research topic in the past years, are supplied. In addition, an analysis of the simultaneous evolution of PADs in academic lab research and industrial commercialization highlighting the parallelism of the technological transfer from academia to industry is displayed. A general overview of the market behaviour, the leading industries in the sector and their commercialized devices is given. Finally, personal opinions of the authors about future perspectives and tendencies in the design and fabrication technology of PADs are disclosed.

Benzo[5]helicene-based conjugated polymers: synthesis, photophysical properties, and application for the detection of nitroaromatic explosives

Benzo[5]helicene-based conjugated polymers were synthesized and demonstrated as fluorescent chemosensors for the highly selective and sensitive detection of nitroaromatic explosives.

Signal enhancement of sensing nitroaromatics based on highly sensitive polymer dots

A new, rapid, sensitive, selective and portable fluorescence detection method for nitroaromatics based on polymer dots (Pdots) had been successfully developed not only in aqueous media but also in the solid state with test strips. The fluorescence quenching rates were proportional to the concentrations of 2,4,6-trinitrophenol (TNP) in the range of 0.2-20.0 μg mL(-1) and p-nitrophenol (PNP) in the range of 0.05-6.0 μg mL(-1), when Pdots were used as ratiometric fluorescent sensors in aqueous solution. The 3σ limit of detection of PNP reached 18.8 ng mL(-1). Compared with polymer-based detection for nitroaromatics in the organic phase, the signal enhancement effect was initially found when Pdots were used to detect nitroaromatics in the aqueous phase. The mechanism of the interaction between Pdots and nitroaromatics was revealed as an electron transfer phenomenon from the electron-rich chromophoric probe to the electron deficient nitroaromatics. The results indicated that Pdots-based detection was particularly suitable for on-site qualitative detection and quantitative analysis of nitroaromatics.

Peptide Functionalized Nanoplasmonic Sensor for Explosive Detection

In this study, a nanobiosensor for detecting explosives was developed, in which the peptide was synthesized with trinitrotoluene (TNT)-specific sequence and immobilized on nanodevice by Au-S covalent linkage, and the nanocup arrays were fabricated by nanoimprint and deposited with Au nanoparticles to generate localized surface plasmon resonance (LSPR). The device was used to monitor slight change from specific binding of 2,4,6-TNT to the peptide. With high refractive index sensing of ~104 nm/RIU, the nanocup device can detect the binding of TNT at concentration as low as 3.12 × 10-7 mg mL-1 by optical transmission spectrum modulated by LSPR. The nanosensor is also able to distinguish TNT from analogs of 2,4-dinitrotoluene and 3-nitrotoluene in the mixture with great selectivity. The peptide-based nanosensor provides novel approaches to design versatile biosensor assays by LSPR for chemical molecules.

Confining the polymerization of aniline to generate yolk–shell polyaniline@SiO2 nanostructures

Yolk–shell nanostructured polyaniline@SiO₂ particles were fabricated by using CeO₂@SiO₂ particles as reactive and confined templates and the samples were applied in drug loading and photothermal release as a proof of concept.