Rapid SABRE Catalyst Scavenging Using Functionalized Silicas.

Area of Science:

• Chemical Engineering
• Materials Science
• Biomedical Imaging

Background:

• Signal amplification by reversible exchange (SABRE) is a promising NMR hyperpolarization technique.
• Iridium catalysts used in SABRE are unsuitable for biomedical applications due to toxicity concerns.

Purpose of the Study:

• To investigate the efficacy of metal scavengers in removing iridium catalyst residues from SABRE solutions.
• To identify optimal scavenger properties for efficient iridium removal.

Main Methods:

• Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to quantify residual iridium.
• Various functionalized silica gel scavengers with different functionalities, chain lengths, and support materials were tested.
• The impact of scavenger quantity on iridium removal was evaluated.

Main Results:

• Specific functionalized silica gels demonstrated high efficiency in removing iridium.
• One optimized scavenger reduced iridium levels to below 1 ppm within 2 minutes.
• Scavenger functionality, chain length, and support identity significantly influenced iridium removal efficiency.

Conclusions:

• Metal scavengers, particularly functionalized silica gels, can effectively remove toxic iridium catalyst residues from SABRE samples.
• This method enables the preparation of biocompatible hyperpolarized agents for potential in vivo use.
• Combining this scavenging approach with techniques like CASH-SABRE could facilitate rapid production of hyperpolarized contrast agents.