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Establishment of a method to determine the magnetic particles in mouse tissues
Yifan Wu1, Wuxu Zhang, Yuxia Wang
1Beijing Institute of Pharmacoloy and Toxicology, Beijing, 100850, People's Republic of China. wangyuxia1962@hotmail.com.
Abstract:
This work is aimed to evaluate a method to detect the residual magnetic nanoparticles (MNPs) in animal tissues. Ferric ions released from MNPs through acidification with hydrochloric acid can be measured by complexation with potassium thiocyanate. MNPs in saline could be well detected by this chemical colorimetric method, whereas the detected sensitivity decreased significantly when MNPs were mixed with mouse tissue homogenates. In order to check the MNPs in animal tissues accurately, three improvements have been made. Firstly, proteinase K was used to digest the proteins that might bind with iron, and secondly, ferrosoferric oxide (Fe3O4) was collected by a magnetic field which could capture MNPs and leave the bio-iron in the supernatant. Finally, the collected MNPs were carbonized in the muffle furnace at 420°C before acidification to ruin the groups that might bind with ferric ions such as porphyrin. Using this method, MNPs in animal tissues could be well measured while avoiding the disturbance of endogenous iron and iron-binding groups.
Insights
This study presents an improved method for detecting residual magnetic nanoparticles (MNPs) in animal tissues. The enhanced technique accurately quanties MNPs, overcoming interference from endogenous iron.
Area of Science:
- Biomedical Engineering
- Materials Science
- Analytical Chemistry
Background:
- Accurate detection of residual magnetic nanoparticles (MNPs) in biological tissues is crucial for safety and efficacy assessments.
- Standard colorimetric methods for MNP detection are often confounded by endogenous iron and iron-binding molecules in tissue homogenates.
- Existing methods lack the sensitivity and specificity required for reliable quantification in complex biological matrices.
Purpose of the Study:
- To develop and validate an improved method for the accurate detection and quantification of residual magnetic nanoparticles (MNPs) in animal tissues.
- To overcome the limitations of existing colorimetric assays, specifically interference from endogenous iron and biological matrix components.
- To establish a robust protocol for MNP detection in diverse animal tissue samples.
Main Methods:
- The method involves acidifying MNPs with hydrochloric acid and measuring released ferric ions using potassium thiocyanate complexation.
- Key improvements include proteinase K digestion to remove interfering proteins, magnetic separation of MNPs from bio-iron, and high-temperature carbonization (420°C) to eliminate iron-binding groups.
- Ferrosoferric oxide (Fe3O4) MNPs were utilized and collected using a magnetic field prior to analysis.
Main Results:
- The enhanced method demonstrated significantly improved sensitivity for MNP detection in mouse tissue homogenates compared to the standard method.
- Magnetic separation effectively isolated MNPs, preventing interference from endogenous iron present in the tissue supernatant.
- Carbonization successfully removed interfering iron-binding groups, such as porphyrins, ensuring accurate ferric ion measurement.
Conclusions:
- The developed method provides a reliable and sensitive approach for detecting residual magnetic nanoparticles in animal tissues.
- This technique effectively mitigates interference from endogenous iron and biological matrix components, enabling accurate quantification.
- The improved protocol is suitable for assessing MNP distribution and clearance in preclinical studies and toxicological evaluations.
