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Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring
Published on: December 9, 2010
Can we accurately quantify nanoparticle associated proteins when constructing high-affinity MRI molecular imaging
Gabriella Rimkus1, Sibylle Bremer-Streck, Cordula Grüttner
1Institute of Diagnostic and Interventional Radiology, University Hospital Jena, Germany. Gabriella.Rimkus@med.uni-jena.de
Contrast Media & Molecular Imaging
|June 24, 2011
Summary
Quantifying proteins coupled to magnetic nanoparticles is crucial for targeted MRI contrast agents. This study shows Bradford and bicinchoninic acid assays can accurately measure protein levels alongside iron oxide nanoparticles without fluorescence or radioactivity.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Analytical Chemistry
Background:
- Targeted magnetic resonance imaging (MRI) contrast agents, such as iron oxide nanoparticles, require precise quantification of conjugated proteins for effective design.
- Existing protein quantification methods are often hindered by the presence of magnetic iron oxide nanoparticles, posing a challenge for developing advanced imaging tools.
Purpose of the Study:
- To determine if proteins can be reliably quantified directly in the presence of magnetic iron oxide nanoparticles.
- To evaluate common protein quantification assays (Bradford and bicinchoninic acid) for their compatibility with iron oxide nanoparticles.
Main Methods:
- Protein quantification using the Bradford assay in the presence of varying concentrations of magnetic iron oxide nanoparticles.
- Protein quantification using the bicinchoninic acid (BCA) assay with and without mathematical corrections for nanoparticle interference.
- Determination of bovine serum albumin (BSA) coupled to dextran-coated magnetic nanoparticles using the corrected BCA assay.
Main Results:
- The Bradford assay was unaffected by the presence of magnetic iron oxide nanoparticles across tested concentrations.
- The BCA assay showed a linear interference from nanoparticle iron, which could be corrected mathematically based on known iron content.
- BSA coupled to magnetic nanoparticles was quantified as 1.5 ± 0.2 µg BSA per 1 mg nanoparticle using the corrected BCA assay.
Conclusions:
- Both Bradford and BCA assays can be used for direct protein quantification with magnetic iron oxide nanoparticles, eliminating the need for fluorescence or radioactivity.
- The developed method allows for more accurate estimation of coupled proteins in targeted MRI probes, potentially improving molecular identification in living organisms.
- This protein quantification approach can enhance current protein coupling procedures for nanoparticle-based contrast agents.
