Smart Wearable Nanopaper Patch for Continuous Multiplexed Optical Monitoring of Sweat Parameters.

Notwithstanding the substantial progress in optical wearable sensing devices, developing wearable optical sensors for simultaneous, real-time, and continuous monitoring of multiple biomarkers is still an important, yet unmet, demand. Aiming to address this need, we introduced for the first time a smart wearable optical sensor (SWOS) platform combining a multiplexed sweat sensor sticker with its IoT-enabled readout module. We employed our SWOS system for on-body continuous, real-time, and simultaneous fluorimetric monitoring of sweat volume (physical parameter) and pH (chemical marker). Herein, a variation in moisture (5-45 µL) or pH (4.0-7.0) causes a color/fluorescence change in the copper chloride/fluorescein immobilized within a transparent chitin nanopaper (ChNP) in a selective and reversible manner. Human experiments conducted on athletic volunteers during exercise confirm that our developed SWOS platform can be efficiently exploited for smart perspiration analysis toward personalized health monitoring. Moreover, our system can be further extended for the continuous and real-time multiplexed monitoring of various biomarkers (metabolites, proteins, or drugs) of sweat or other biofluids (for example, analyzing exhaled breath by integrating onto a facemask).

Moving toward smart biomedical sensing.

The development of novel biomedical sensors as highly promising devices/tools in early diagnosis and therapy monitoring of many diseases and disorders has recently witnessed unprecedented growth; more and faster than ever. Nonetheless, on the eve of Industry 5.0 and by learning from defects of current sensors in smart diagnostics of pandemics, there is still a long way to go to achieve the ideal biomedical sensors capable of meeting the growing needs and expectations for smart biomedical/diagnostic sensing through eHealth systems. Herein, an overview is provided to highlight the importance and necessity of an inevitable transition in the era of digital health/Healthcare 4.0 towards smart biomedical/diagnostic sensing and how to approach it via new digital technologies including Internet of Things (IoT), artificial intelligence, IoT gateways (smartphones, readers), etc. This review will bring together the different types of smartphone/reader-based biomedical sensors, which have been employing for a wide variety of optical/electrical/electrochemical biosensing applications and paving the way for future eHealth diagnostic devices by moving towards smart biomedical sensing. Here, alongside highlighting the characteristics/criteria that should be met by the developed sensors towards smart biomedical sensing, the challenging issues ahead are delineated along with a comprehensive outlook on this extremely necessary field.

A new bio-compatible Cd2+-selective nanostructured fluorescent imprinted polymer for cadmium ion sensing in aqueous media and its application in bio imaging in Vero cells.

Cadmium is a very toxic element found in various aqueous samples. The majority of the highly selective fluorescent ligands, designed for cadmium ion sensing, are hydrophobic compounds, thus making them inactive in aqueous media. Fluorescent imprinted polymers, synthesized by the proficient combination of hydrophilic functional monomers and hydrophobic ligands, may give a new and highly selective opportunity for utilizing most fluorescent ligands for toxic metal ion sensing in aqueous media. A novel fluorescent Cd2+-imprinted polymer was synthesized based on the co-polymerization of a mixture of acryl amide, vinyl benzene and ethylene glycol dimethacrylate in the presence of a 5-((3-hydroxynaphthalen-2-yl)methylene)pyrimidine-2,4,6(1,3,5)-trione (HMPT)-Cd2+ complex. The polymer was characterized by FT-IR spectroscopy, scanning electron microscopy and thermogravimetric analysis. Cadmium ion recognition by IIP created a new emission peak at about 502 nm based on the ICT mechanism, which was different from the emission peak of IIP in the absence of Cd2+ (440 nm). The non-imprinted polymer showed a fluorescence emission at about 500 nm, which was not affected by Cd2+, highlighting the recognition sites of IIP. The opto-sensor (IIP) exhibited a dynamic linear response range of 10-0.05 µM with the limit of detection (LOD) and quantification (LOQ) of 12.3 and 41 nM, respectively. Also, the relative standard deviation (RSD) of 3 separate determinations was 3.68%. Moreover, the developed chemosensor was highly selective for Cd2+ since the IIP fluorescence was not affected by the presence of other metal ions such as Zn2+, Cu+, Mn2+, Co2+, Ni2+, and Pb2+. The synthesized IIP can be used as a fluorescent probe for cadmium detection in live cells because of its minor cytotoxic effect on them.