Deep-tissue NIR-II bioimaging performance of Si-based and InGaAs-based imaging devices using short-wave infrared persistent luminescence

Abstract

Bioimaging in the second near-infrared (NIR-II; 950–1700 nm) window, employing InGaAs-based cameras, exhibits superior clarity and resolution in visualizing shallow structures (<3 mm), yet it falls short in effectively imaging deep-tissue features. The subpar performance of deep-tissue NIR-II imaging is largely attributed to shortcomings in imaging contrast agents, primarily concerning their luminescence brightness and wavelengths, with minimal consideration given to deficiencies in InGaAs cameras. Here, we use a MgGeO₃:Yb³⁺ short-wave infrared (SWIR) persistent luminescent phosphor emitting at 950–1100 nm as a contrast agent to assess the deep-tissue bioimaging capabilities of both an InGaAs camera and a Si CCD camera under identical imaging conditions in thick chicken breast tissues (5–20 mm), thick mice bodies (10–20 mm), and internal mice organs (gastrointestinal tracts, lungs, and livers). Despite the significantly higher quantum efficiency of the InGaAs camera (∼80–85%) compared to the Si camera (∼5–30%) in detecting 950–1100 nm SWIR light, the former exhibits notably inferior performance overall in imaging deep-tissue features, particularly in scenarios with faint imaging signals, attributable to the pronounced interference of its inherently high dark current. Nonetheless, when provided with sufficiently intense SWIR imaging signals, the InGaAs camera outperforms the Si camera in terms of clarity, even in chicken tissues of 10 mm thickness and in the stomachs of mice.