A circular RNA-guided CRISPR/Cas12a fluorescent test to detect myeloperoxidase enzyme activity

Detection limits of 0.79 ng/mL for myeloperoxidase (MPO) were achieved using a CRISPR/Cas12a-based sensing platform.

• The sensing platform detects MPO activity by generating hypochlorous acid (HClO), which activates a fluorescent reporter.
• This system showed excellent selectivity against various reactive species and biomolecular interferents.
• Performance was reliable in 1% fetal bovine serum, with recoveries ranging from 92.87% to 112.54%.
• Stable sensor responses were maintained over 8 weeks, indicating strong structural integrity of the circular crRNA-PS.
• The platform also facilitated inhibitor screening, revealing IC₅₀ values of 127.2 μM for SHA and 0.81 μM for 4-ABAH.

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