Reactive oxygen species responsive theranotics nanoprobe for chemical exchange saturation transfer imaging in osteoarthritis

Motivation: There is still a lack of noninvasive technique in quantifying the acidic extracellular pH of damaged cartilage in early osteoarthritis (OA). Goal(s): We aimed to fabricate an advance reactive oxygen species (ROS) responsive CEST-MRI contrast agent for damaged cartilaged imaging and treatment in OA. Approach: We use CEST-MRI to investigate whether our sythesized PLGE-TK-PEG@PDA-SA nanoparticles repond to ROS accumulating in damaged cartilage could result in the exsistance of CEST signal, while no CEST signal would be tested in normal cartilage without excessive ROS. Results: The PLGA-TK-PEG@PDA-SA nanoparticles could effectively respond to ROS and then produce significant CEST effect for precisely pH measurement. Impact: The novel PLGA-TK-PEG@PDA-SA CEST- MRI contrast could be used to noninvasively monitor the extracellular pH of cartilage in osteoarthritis, and eliminate excessive ROS to defend against its damage to cartilage. This smart, sensitive ROS-responsive nanoprobe is promising for OA theranostics.