Peptide Nanocarriers for Detection of Heavy Metal Ions Using Resistive Pulse Sensing

Abstract

The use of nanocarriers within resistive pulse sensing facilitates the detection and quantification of analytes. To date the field has been dominated by polyionic carriers or nanomaterials. Together they combine the recognition elements of a ligand with a stable support, facilitating the sample handling, analysis times, and multiplex detection. Here we develop the use of peptide-functionalized superparamagnetic nanocarriers to extract and quantify metal ions in solution. The interaction between nickel and the peptide ligand is measured as a change in translocation velocity of the carrier. The magnitude of change is proportional to the concentration of the metal ions in solution. Unlike DNA aptamers where a change in the tertiary structure and the folding of the polyanionic backbone influences the carrier velocity, the peptides here had a lower net charge under the assay conditions. To try and enhance the signal we engineered charged groups within the peptide to explore the effects on the signal. In all cases the metal ion binding dominated the velocity of the carrier. The assay was shown to work across 3 orders of magnitude and can detect Ni 2+ in the presence of some other heavy metal ions. We demonstrate this by quantifying Ni 2+ in both tap and pond water. The work allows for future multiplexed sensing strategies using both peptides and DNA aptamers in resistive pulse sensors.

A Tunable Three-Dimensional Printed Microfluidic Resistive Pulse Sensor for the Characterization of Algae and Microplastics

“…[5][6][7][8][9] New manufacturing processes, coupled with improved electronics have enabled them to characterise analytes' sizes [10][11][12] , concentrations 13,14 , shapes 15 and charges. 16,17 As a result, RPS has found numerous applications within environmental monitoring of, for example: bacteria 18 , algae 19 , and heavy metal ions 20 . The sensing system is simple, monitoring the temporary changes in current caused by the translocation of an analyte through a narrow constriction, termed a sensing region.…”

A Multiuse Nanopore Platform with Disposable Paper Analytical Device for the Detection of Heavy Meatal Ions

“…This was not considered an issue as this test could be used to indicate the presence of metal ions and if quantification is needed the test solution can be used in a particle assay as previously described. [46][47][48] However, as shown in Figure 5ai and 5aii, when tested on different pores on different days it was possible to measure nickel(II) concentrations down to 0.25 μM, which is below the environmentally acceptable limit for drinking water. 74 Repeats on two more pores are shown in Figure S8.…”

“…Further, as previously demonstrated the pore can still measure particles after coating with PAAMA, so should the PAD indicate the presence of nickel(II) is it possible to measure the quantity of nickel(II) using the previously developed method by simply adding peptide functionalised particles to the sample. 48 As a demonstration of the assays ability to be used in more complex matrices, environmental water samples were collected. Tap water from the lab tap and pond water from a local pond was collected for testing.…”

Nanopore Detection of Metal Ions: Current Status and Future Directions

“…Moreover, this nanopore sensor was selective: detection of Ni 2+ ion in the presence of some other heavy metal ions and quantification of Ni 2+ in both tap and pond water were successfully accomplished. [ 96 ]…”