Responsive food packaging is an emerging field in food packaging research and the food industry. Unlike active packaging, responsive packaging systems react to stimuli in the food or the environment to enable real time food quality and food safety monitoring or remediation. This review attempts to define and clarify the different classes of food packaging technologies. Special emphasis is given to the description of responsive food packaging including its technical requirements, the state of the art in research and the current expanding market. The development and promises of stimuli responsive materials in responsive food packaging are addressed, along with current challenges and future directions to help translate research developments into commercial products.

Selective removal of aqueous mercury to levels below 10 ng L−1 or part per trillion remains an elusive goal for public health and environmental agencies. Here, it is shown that a low‐cost nanocomposite sponge prepared by growing selenium (Se) nanomaterials on the surface and throughout the bulk of a polyurethane sponge exhibits a record breaking‐mercury ion (Hg2+) removal rate, regardless of the pH. The exposure of aqueous solutions containing 10 mg L−1–12 ng L−1 Hg2+ to the sponge for a few seconds results in clean water with undetectable mercury levels (detection limit: 0.2 ng L−1). Such performance is far below the acceptable limits in drinking water (2 µg L−1), industrial effluents (0.2 µg L−1), and the most stringent surface water quality standards (1.3 ng L−1). The sponge shows a unique preference for Hg, does not retain water nutrients, and can significantly reduce the concentration of other heavy metal pollutants. Furthermore, the sponge shows no cytotoxic effect on human cells while exhibiting strong antimicrobial properties. The high affinity of Hg for Se results in irreversible sequestration and detoxification of mercury by the sponge, confirming the suitability for landfill disposal.

Here we report a disposable, cost effective electrochemical paper-based sensor for the detection of both nitrate and mercury ions in lake water and contaminated agricultural runoff. Disposable carbon paper electrodes were functionalized with selenium particles (SePs) and gold nanoparticles (AuNPs). The AuNPs served as a catalyst for the reduction of nitrate ions using differential pulse voltammetry techniques. The AuNPs also served as a nucleation sites for mercury ions. The SePs further reinforced this mercury ion nucleation due to their high binding affinity to mercury. Differential pulse stripping voltammetry techniques were used to further enhance mercury ion accumulation on the modified electrode. The fabricated electrode was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electrochemistry techniques. The obtained results show that the PEG-SH/SePs/AuNPs modified carbon paper electrode has a dual functionality in that it can detect both nitrate and mercury ions without any interference. The modified carbon paper electrode has improved the analytical sensitivity of nitrate and mercury ions with limits of detection of 8.6µM and 1.0ppb, respectively. Finally, the modified electrode was used to measure nitrate and mercury in lake water samples.

With increasing biomedical and engineering applications of selenium nanospheres (SeNS), new efficient methods are needed for the synthesis and long-term preservation of these nanomaterials. Currently, SeNS are mostly produced through the biosynthesis route using microorganisms or by using wet chemical reduction, both of which have several limitations in terms of nanoparticle size, yield, production time and long-term stability of the nanoparticles. Here, we introduce a novel approach for rapid synthesis and long-term preservation of SeNS on a solid microporous support by combining a mild hydrothermal process with chemical reduction. By using a natural sponge as a solid three-dimensional matrix for nanoparticle growth, we have synthesized highly monodisperse spherical nanoparticles with a wide size range (10-1000 nm) and extremely high yield in a relatively short period of time (1 h). Additionally, the synthesized SeNS can be stored and retrieved whenever needed by simply washing the sponge in water. Keeping the nanospheres in the support offers remarkable long-term stability as particles left on the sponge preserve their morphological and colloidal characteristics even after eight months of storage. Furthermore, this work reveals that SeNS can be used for efficient mercury capture from contaminated waters with a record-breaking mercury removal capacity of 1900 mg g.

The COVID-19 pandemic presents a unique challenge to the healthcare community due to the high infectivity rate and need for effective personal protective equipment. Zinc oxide nanoparticles have shown promising antimicrobial properties and are recognized as a safe additive in many food and cosmetic products. This work presents a novel nanocomposite synthesis approach, which allows zinc oxide nanoparticles to be grown within textile and face mask materials, including melt-blown polypropylene and nylon-cotton. The resulting nanocomposite achieves greater than 3 log10 reduction (≥ 99.9%) in coronavirus titer within a contact time of 10 min, by disintegrating the viral envelope. The new nanocomposite textile retains activity even after 100 laundry cycles and has been dermatologist tested as non-irritant and hypoallergenic. Various face mask designs were tested to improve filtration efficiency and breathability while offering antiviral protection, with Claros’ design reporting higher filtration efficiency than surgical masks (> 50%) for particles ranged 200 nm to 5 µm in size.