Digitization of Colorimetric Sensor Technologies for Food Safety

TL;DR: This review surveys recent advances in poly(lactic acid) (PLA) stereochemistry, highlighting the impact of microstructure on material properties and applications, including packaging, healthcare, and electronics, with a focus on poly(L-lactic acid) (PLLA) and other stereosequences.

Abstract: Leveraging the rich stimuli-response of polymers represents a promising direction towards optical communication/encryption. Sign language, which relies on specific geometric change for secured communication, has been widely used for the same purpose since ancient time. We report a strategy that combines both in a validated manner with a hydrogel that not only carries encrypted optical information but also has the hidden behavior to morph geometrically. In particular, the shape morphing behavior is programmable by controlling the oriented state of the polymer chain in the thermo-responsive network. Whether the shape morphing direction is positive (bending) or negative (flattening) cannot be predicted when the polymerization methods are not informed, revealing a hidden manner. Through deciphering the coupling of chain elastic stresses and thermo-induced deswelling stress, the hydrogel can perform designed and diversified 4D morphing which represents evolution of 3D geometries with time as the fourth dimension. Consequently, the corresponding optical information can be gated based on these geometric features, thereby decrypting the correct permutation of information. Our approach that utilizes the geometric 4D morphing for gated verification of optical information offers a strategy for enhancing the security of communication in ways that are quite different from existing strategies. Stimuli responsive hydrogels can be used in optical communication, but are not always as complex as required. Here, the authors report the use of 4D hydrogel morphing for gated verification of optical information.

TL;DR: Paper-based point-of-care analytical devices are particularly suitable for deployment in low-resource settings and have substantial applicability for bacteria detection and discuss challenges and opportunities for future development as discussed by the authors .

TL;DR: Gold-nanoparticles can be used as a robust tool for bio-sensing based on localized surface plasmon resonance (LSPR) as discussed by the authors, and both local refractive index change and self-assembly of the nanoparticles can le...

TL;DR: This work has compared three main types of colorimetric methods - enzymatic reactions, silver deposition catalyzed by gold nanoparticles, and polymerization-based amplification - in a paper-based immunoassay for detection of Plasmodium falciparum histidine-rich protein 2, a biomarker of malarial infection.

TL;DR: In this paper , a colorimetric film was developed from polyvinyl alcohol/sodium carboxymethyl cellulose (PVA/CMC-Na, CPA) incorporated with anthocyanins (AHO) or betacyanins (BTA) or AHO and BTA mixtures (in the mass ratios of 2:2, 3:1, 1:3) for intelligent packaging.