Rapid and sensitive detection of urinary KIM-1 using fully printed photonic crystal microarrays

Urinary kidney injury molecule 1 (uKIM-1) serves as a reliable marker for the early diagnosis of acute kidney injury (AKI). The rapid and facile detection of changes in uKIM-1 is essential for early AKI diagnosis, ultimately improving the prognosis of patients. In this study, we developed a fully printed photonic crystal-integrated microarray with photonic crystal-enhanced fluorescence properties, which can detect uKIM-1 levels at the point-of-care. We confirmed its efficacy in the early diagnosis of AKI using clinical urine specimens. Direct quantitative detection of uKIM-1 was achieved within 10 min. The lowest limit of detection is 8.75 pg·mL⁻¹ with an accuracy of 94.2%. The diagnostic efficacy was validated using 86 clinical urine samples, highlighting the high sensitivity and stability of the photonic crystal microarray. Consequently, a facile and reliable immunoassay was designed and prepared for the rapid quantitative detection of uKIM-1, which is crucial for the early identification and convenient detection of AKI in hospital or community settings. Rapid, convenient, cost-effective, and long-term monitoring of changes in uKIM-1 levels can assist clinicians in making timely adjustments to treatment regimens, preventing the transition from AKI to chronic kidney disease (CKD), improving the quality of life of patients with AKI, and reducing healthcare costs. It highlights the advantages of utilizing urine samples as a noninvasive and easily accessible medium for early detection and monitoring of kidney-related conditions.