Near‐Infrared Dual‐Modal Sensing of Force and Temperature in Total Knee Replacement Using Mechanoluminescent Phosphor of Sr 3 Sn 2 O 7 : Nd, Yb

Abstract Knee replacement surgery confronts challenges including patient dissatisfaction and the necessity for secondary procedures. A key requirement lies in dual‐modal measurement of force and temperature of artificial joints during postoperative monitoring. Here, a novel non‐toxic near‐infrared (NIR) phosphor Sr 3 Sn 2 O 7 :Nd, Yb, is designed to realize the dual‐modal measurement. The strategy is to entail phonon‐assisted upconversion luminescence (UCL) and trap‐controlled mechanoluminescence (ML) in a single phosphor well within the NIR biological transmission window. The phosphor is embedded in medical bone cement forming a smart joint in total knee replacements illustrated as a proof‐of‐concept. The sensing device can be charged in vitro by a commercial X‐ray source with a safe dose rate for ML, and excited by a low power 980 nm laser for UCL. It attains impressive force and temperature sensing capabilities, exhibiting a force resolution of 0.5% per 10 N, force detection threshold of 15 N, and a relative temperature sensitive of up to 1.3% K −1 at 309 K. The stability against humidity and thermal shock together with the robustness of the device are attested. This work introduces a novel methodological paradigm, paving the way for innovative research to enhance the functionality of artificial tissues and joints in living organisms.