Quantifying platinum binding on protein-functionalized magnetic microparticles using single particle-ICP-TOF-MS.
Veronica C Bradley1, Benjamin T Manard1, Lyndsey Hendriks2
1Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. manardbt@ornl.gov.
Analytical Methods : Advancing Methods and Applications
|April 19, 2024
Summary
A new analytical method, single particle-inductively coupled plasma-time-of-flight-mass spectrometry (SP-ICP-TOF-MS), accurately measures platinum binding efficiency on microparticles. This technique distinguishes bound from unbound platinum, overcoming limitations of bulk digestion methods.
Area of Science:
- Analytical Chemistry
- Materials Science
- Nanotechnology
Background:
- Accurate quantification of metal binding to microparticles is crucial for applications in diagnostics and therapeutics.
- Traditional bulk digestion methods can overestimate metal loading due to unbound analytes.
- Protein-coated magnetic microparticles are utilized in various biomedical applications requiring precise characterization.
Purpose of the Study:
- To develop and validate a single particle-inductively coupled plasma-time-of-flight-mass spectrometry (SP-ICP-TOF-MS) method for determining platinum binding efficiency.
- To compare the accuracy of SP-ICP-TOF-MS with traditional bulk digestion-inductively coupled plasma-mass spectrometry (ICP-MS) for platinum quantification.
- To assess the platinum loading and particle-platinum association on protein-coated magnetic microparticles.
Main Methods:
- Development of an SP-ICP-TOF-MS analytical procedure for simultaneous detection of platinum and iron.
- Characterization of 1 μm magnetic microparticles using both bulk digestion-ICP-MS and SP-ICP-TOF-MS.
- Quantification of platinum loading per particle and determination of particle-platinum association for streptavidin- and azurin-coated microparticles.
Main Results:
- SP-ICP-TOF-MS enabled quasi-simultaneous detection of all nuclides, facilitating concurrent measurement of platinum and iron.
- Results from SP-ICP-TOF-MS and bulk digestion-ICP-MS agreed for particle characterization, but SP-ICP-TOF-MS provided accurate platinum loading.
- Quantified platinum loading was 0.18 ± 0.02 fg/particle (streptavidin) and 0.32 ± 0.02 fg/particle (azurin), with >65% particle-platinum association.
- Bulk ICP-MS overestimated platinum loading due to the presence of unbound platinum.
Conclusions:
- SP-ICP-TOF-MS is a superior method for accurately quantifying platinum binding efficiency on microparticles compared to bulk digestion techniques.
- The developed method eliminates laborious sample preparation and allows for differentiation between bound and unbound platinum.
- This particle-by-particle quantification approach has broad applicability for various single particle-based analyses.
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