Open-Source Benchtop Magnetophotometer for Characterizing the Magnetic Susceptibility of Suspended Nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Analytical Chemistry

Background:

• Magnetic nanoparticles (MNPs) are crucial for biological and environmental applications.
• Accurate magnetic susceptibility is key for MNP performance.
• Conventional susceptibility measurements on dry MNPs are often inaccurate for their intended use in suspension.

Purpose of the Study:

• To design and validate a novel instrument, the magnetophotometer (MAP).
• To measure the effective magnetic susceptibility of MNPs in their operational liquid suspension.
• To provide a more relevant metric for MNP suitability in various applications.

Main Methods:

• Development of a magnetophotometer (MAP) utilizing differential optical spectroscopy.
• Creation of a mathematical model to calculate effective magnetic susceptibility from MAP data.
• Validation using diverse MNPs (varying composition, size, architecture, coatings).

Main Results:

• The MAP instrument successfully characterizes the effective magnetic susceptibility of MNPs in suspension.
• The developed mathematical model accurately calculates susceptibility from MAP data.
• MAP testing was demonstrated to be nondestructive, preserving bioconjugate bioactivity.

Conclusions:

• The magnetophotometer (MAP) provides a relevant and accurate method for assessing MNP magnetic properties in suspension.
• This technique overcomes limitations of traditional dry-powder measurements.
• MAP offers a viable path for non-damaging, in-line quality control of MNPs in bioconjugated applications.