Related Experiment Video
Updated: Jul 4, 2025
Fully Automated Centrifugal Microfluidic Device for Ultrasensitive Protein Detection from Whole Blood
Published on: April 16, 2016
Pb2+-Selective Nanoemulsion-Integrated Single-Entity Electrochemistry for Ultrasensitive Sensing of Blood Lead
Hiranya Madawala1, Surendra Raj Puri1, Delaney Weaver1
1Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States.
Insights
Detecting lead (Pb2+) in children is crucial for preventing neurodevelopmental issues. This study introduces a novel nanoemulsion-integrated single-entity electrochemistry (NI-SEE) method for ultrasensitive blood lead detection, achieving detection limits down to parts per trillion.
Area of Science:
- Analytical Chemistry
- Environmental Science
- Biomedical Engineering
Background:
- Lead (Pb2+) exposure poses significant risks to children's neurological development, necessitating highly sensitive detection methods.
- Current analytical techniques struggle to achieve the sub-parts per billion (ppb) detection limits required for ultralow blood lead levels.
- Existing methods lack the sensitivity and selectivity for accurate quantification of lead at environmentally and biologically relevant concentrations.
Purpose of the Study:
- To develop an ultrasensitive method for detecting lead (Pb2+) in blood serum.
- To achieve detection limits significantly lower than current standards for blood lead monitoring.
- To explore the potential of nanoemulsion-integrated single-entity electrochemistry (NI-SEE) for lead ion sensing.
Main Methods:
- Utilized nanoemulsion (NE)-integrated single-entity electrochemistry (NI-SEE) with Pb2+-selective ionophores encapsulated within NEs.
- Leveraged high thermodynamic selectivity and partition coefficients for Pb2+-Pb-ionophore complexes within NEs.
- Employed molecular dynamics simulations to elucidate intermolecular interactions and optimize sensing performance.
- Applied cathodic potential to a Pt electrode to suppress hydroxyl radical formation and enhance sensitivity.
Main Results:
- Achieved an unprecedented detection limit of 20 parts per trillion (ppt) in aqueous solutions.
- Established a lower limit of quantitation of 40 ppb in blood serums.
- Demonstrated enhanced current intensity in NI-SEE due to favorable intermolecular interactions within NEs.
- Confirmed the suppression of hydroxyl radical formation contributing to high sensitivity.
Conclusions:
- The NI-SEE approach offers a highly sensitive and selective method for detecting lead (Pb2+).
- This technology holds promise for practical environmental and biomedical applications, including blood lead monitoring.
- The developed platform can serve as a nanoreactor for studying ion-ionophore recognition stoichiometry.
Abstract:
Unequivocally, Pb2+ as a harmful substance damaging children's brain and nerve systems, thereby causing behavior and learning disabilities, should be detected much lower than the elevated blood lead for children, 240 nM, endorsed by US CDC considering the unknown neurotoxic effects, yet the ultralow detection limit up to sub-ppb level remains a challenge due to the intrinsically insufficient sensitivity in the current analytical techniques. Here, we present nanoemulsion (NE)-integrated single-entity electrochemistry (NI-SEE) toward ultrasensitive sensing of blood lead using Pb-ion-selective ionophores inside a NE, i.e., Pb2+-selective NE. Through the high thermodynamic selectivity between Pb2+ and Pb-ionophore IV, and the extremely large partition coefficient for the Pb2+-Pb-ionophore complex inside NEs, we modulate the selectivity and sensitivity of NI-SEE for Pb2+ sensing up to an unprecedentedly low detection limit, 20 ppt in aqueous solutions, and lower limit of quantitation, 40 ppb in blood serums. This observation is supported by molecular dynamics simulations, which clearly corroborate intermolecular interactions, e.g., H-bonding and π*-n, between the aromatic rings of Pb-ionophore and lone pair electrons of oxygen in dioctyl sebacate (DOS), plasticizers of NEs, subsequently enhancing the current intensity in NI-SEE. Moreover, the highly sensitive sensing of Pb2+ is enabled by the appropriate suppression of hydroxyl radical formation during NI-SEE under a cathodic potential applied to a Pt electrode. Overall, the experimentally demonstrated NI-SEE approach and the results position our new sensing technology as potential sensors for practical environmental and biomedical applications as well as a platform to interrogate the stoichiometry of target ion-ionophore recognition inside a NE as nanoreactors.
