Colorimetric Nanoparticle-Embedded Hydrogels for a Biosensing Platform

Abstract

Hydrogels containing colorimetric nanoparticles have been used for ion sensing, glucose detection, and microbial metabolite analyses. In particular, the rapid chemical reaction owing to both the hydrogel form of water retention and the sensitive color change of nanoparticles enables the rapid detection of target substances. Despite this advantage, the poor dispersibility of nanoparticles and the mechanical strength of nanoparticle–hydrogel complexes have limited their application. In this study, we demonstrate a milliliter agarose gel containing homogeneously synthesized polyaniline nanoparticles (PAni-NPs), referred to as PAni-NP–hydrogel complexes (PNHCs). To fabricate the optimal PNHC, we tested various pH solvents based on distilled water and phosphate-buffered saline and studied the colorimetric response of the PNHC with thickness. The colorimetric response of the prepared PNHC to the changes in the pH of the solution demonstrated excellent linearity, suggesting the possibility of using PNHC as a pH sensor. In addition, it was verified that the PNHC could detect minute pH changes caused by the cancer cell metabolites without cytotoxicity. Furthermore, the PNHC can be stably maintained outside water for approximately 12 h without deformation, indicating that it can be used as a disposable patch-type wearable biosensing platform.

Protein‐based metal bio‐cleaner for detoxification of wastewater

“…Hence, the presence of specific metals in a solution or biological system can be detected by the metal‐induced changes in the fluorescence of fluorescent protein‐based biosensors. Earlier, fluorescent protein‐based biosensors were reported with static quenching, energy transfer between chromophore and colored metal ion and altered protein structure 9,10,19‐25 . In this study, the confirmation of protein with novel chemical amine moiety allowed us to evaluate the fluorescent protein‐based reagent‐less metal sensing system.…”

“…Frequently, two experimental approaches, namely reassignment of sense (residue-specific incorporation) and nonsense suppression (site-specific incorporation), are used for in vivo incorporation of NCAAs into recombinant proteins. [17][18][19][20][21][22][23][24][25] In the work reported here, we aimed to introduce donor-acceptor non-natural chemistry in the GFP chromophore, offering significant Stokes shifts to GFP. 11,26 We aimed to incorporate aminotyrosine as an electron-donating group (amine group) into the GFP chromophore for the development of an efficient red-shifted fluorescent protein-based biosensor that can also act as a bio-cleaner for the removal of Cu 2+ ions from environmental samples.…”

“…Synthetic NCAAs offer non‐natural potential with new functional chemistry for proteins with enhanced spectral properties. Frequently, two experimental approaches, namely reassignment of sense (residue‐specific incorporation) and nonsense suppression (site‐specific incorporation), are used for in vivo incorporation of NCAAs into recombinant proteins 17‐25 . In the work reported here, we aimed to introduce donor–acceptor non‐natural chemistry in the GFP chromophore, offering significant Stokes shifts to GFP 11,26 .…”

A regression-based machine learning approach for pH and glucose detection with redox-sensitive colorimetric paper sensors

“…However, humans have limitations in creating and applying new quantiable color indices. [26][27][28] Also, the image processing itself is strongly inuenced by external requirements (light source, temperature, distance, etc.). 29,30 To solve this problem, it is necessary to develop a colorimetric paper sensor based on a new platform that can reduce errors due to external factors and analyze the color change in the sensor with high precision.…”

“…However, humans have limitations in creating and applying new quantifiable color indices. 26–28 Also, the image processing itself is strongly influenced by external requirements (light source, temperature, distance, etc. ).…”