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Providing viral load numbers of infection events aids in the identification of disease severity and in the effective overall patient management. Gold-standard polymerase chain reaction (PCR) techniques make this possible but cannot be applied at the point of need and in low-resource settings. Here, we report on the development of a compact analytical platform that can detect a conserved sequence of the RNA of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) in 40 min in nasopharyngeal swab samples without the need for any previous purification or gene amplification steps. It combines electrochemical and paper fluidic approaches together with a sandwich hybridization assay performed on magnetic nanoparticles (MNPs) modified with a tailor-designed capture DNA hairpin. The device proves to quantitatively detect viral RNA in a retrospective study carried out with nasopharyngeal swab samples. A sensitivity of 100% and a specificity of 93% were estimated by the receiver operating characteristic (ROC) analysis. However, although molar concentration values of the target RNA sequence are provided, these estimates do not fully correlate with the viral load numbers estimated by RT-qPCR over the whole Ct sample range. Empirical studies have been carried out that have provided clear insights into this hurdle and simple solutions to overcome it, without depriving the device of the features required for potential use in a point-of-care (PoC) environment.

Anal. Chem. 2025, 97, 22, 11863–11873. DOI: 10.1021/acs.analchem.5c01605

Internet-of-Things (IoT) is considered one of the primary enablers of the next digital transformation wave. Generating and exchanging data between the increasing number of delocalized sensors comes with the need for high-performance portable power sources that also meet environmental and social responsibility standards. This article presents a portable power source to meet the energy requirements of IoT devices in the smart packaging sector that has been designed-by-purpose in an ecologically benign way since the early development stage. To minimize the environmental impact throughout its life cycle, the battery follows the value chain of paper and cardboard, from material sourcing to disposability. Naturally abundant materials, such as cellulose derivates and alginate biopolymers, are prioritized to create the separator and contain the redox species. Manufacturing techniques, easily implementable in the packaging industry, are used to fabricate an adhesive label-like battery (based on layered components) and engrave the current collectors, via laser-induced graphene. The prototype's energy adaptation capability is demonstrated by directly powering two applications particularly appealing for smart packaging, i.e., a printed electrochromic display and a wireless tracker device. Once depleted, the battery is compatible with paper and cardboard recycling standardized processes. The reconceptualization of the whole battery life cycle leads to the generation of a disruptive power source concept that aims to be an enabler of a sustainable digitalization of society.

Designed-by-purpose power sources: a cardboard primary battery for smart packaging. Energy and Environmental Science. DOI: 10.1039/D4EE00306C