Hyperpolarized 129Xe Atoms Sense the Presence of Drug Molecules in Nanohosts Revealed by Magnetic Resonance Imaging

Assessing the effectiveness of nanomedicines involves evaluating
the drug content at the target site. Currently, most research focuses on
monitoring the signal responses from loaded drugs, neglecting the changes caused
by the nanohosts. Here, we propose a strategy to quantitatively evaluate the
content of loaded drugs by detecting the signal variations resulting from the
alterations in the microenvironment of the nanohosts. Specifically, hyperpolarized
(HP) 129Xe atoms are employed as probes to sense the nanohosts’ environment
and generate a specific magnetic resonance (MR) signal that indicates their
accessibility. The introduction of drugs reduces the available space in the
nanohosts, leading to a crowded microenvironment that hinders the access of the
129Xe atoms. By employing 129Xe atoms as a signal source to detect the alterations
in the microenvironment, we constructed a three-dimensional (3D) map that
indicated the concentration of the nanohosts and established a linear relationship
to quantitatively measure the drug content within the nanohosts based on the corresponding MR signals. Using the developed
strategy, we successfully quantified the uptake of the nanohosts and drugs in living cells through HP 129Xe MR imaging. Overall, the
proposed HP 129Xe atom-sensing approach can be used to monitor alterations in the microenvironment of nanohosts induced by
loaded drugs and provides a new perspective for the quantitative evaluation of drug presence in various nanomedicines.