Multi-array wax paper-based platform for the colorimetric determination of metal ions in human biofluids: Smart wearable optical sensor (SWOS) towards bioanalysis

Abstract

Metal ions are needed to keep the human body healthy, as their presence has or can affect vital biological functions in humans and their existence is essential for survival. Current methods for metal ion analysis struggle with challenges such as low sensitivity, lack of selectivity and complex procedures. Therefore, clinicians urgently need an efficient analysis method/technique. In the present study, a new chemosensing method was proposed for the sensitive recognition of Co(II), Cu (II), and Pb (II) ions. In this method, a chemical reaction occurs between metal ions and triangular silver nanoparticles (TA-AgNPs) which served as optical prob, resulting in a color change detected by an engineered colorimetric method. UV–visible spectrophotometry also confirms the reaction, as the interaction between metal ions and TA-AgNPs causes a significant change in the absorption spectrum. This enables the rapid and reliable measurement of these important metal ions with a detection limit of less than 10 nM to 300 mM in human body fluids. Finally, Co(II), Cu (II), and Pb (II) cations were determined by a novel microfluidic chemosensor which engineered by multi-array wax paper-based method. Therefore, a novel portable photo-sensor was developed for the sensitive and specific monitoring of Co(II), Cu (II), and Pb (II) cations in human real samples. In the presence of metal ions, constructed microfluidic paper-based colorimetric devices (μPCDs) work based on color alternation of the sensing probe, such that the blue color of the TA-AgNPrs solution was changed to light orange in the presence of Co(II), and Cu(II) was changed to yellow, Pb(II) was changed to light blue which confirmed suitable application of the engineered platform for the rapid identification of ions. Therefore, an innovative method was suggested for the in-situ and on-demand opto-analysis of metal ions in human urine samples which is expected to help improve environmental health and safety in the workplace.