When combined with photoacoustic probes as exogenous contrast agents, PAI can assist in the visualization of pharmaceutical research and diagnostic treatment, such as studying the dynamics of injection sites of near-infrared dye-labeled insulin preparations (55), validating the targeting of melanin-based targeted nanodrugs for the treatment of diabetic nephropathy (56), and developing novel probes for detecting diabetic liver injury (10), among other applications. The gene discussed is INS; the disease is diabetic kidney disease.