Ultrasensitive aptamer-functionalized Cu-MOF fluorescent nanozyme as an optical biosensor for detection of C-reactive protein

In the present work, an aptasensing method based on integration of RNA on Cu-MOF was developed for detection of C-Reactive Protein (CRP). Cu-MOF showed stimulated fluorescence and mimetic peroxidase enzymatic activity at the time and can be used as dual-signal transduction. CRP binding RNA was used as a highly selective recognition element and immobilized on the Cu-MOF. The immobilized RNA can block the peroxidase activity and fluorescence of the signal traducer probe. Adding CRP to the RNA/Cu-MOF will release RNA from the surface of Cu-MOF and recover both the stimulated fluorescence and peroxidase activity. A biosensor was built for detection of CRP using the two modes of transduction, either colorimetry or fluorometry. A dynamic linear range was obtained from 0.1 to 50 ng mL-1with a limit of detection (LOD) as small as 40 pg mL-1was calculated in fluorescence mode and 240 pg mL-1 as LOD in colorimetry mode. The LODs are lower than the LOD of nephelometric techniques used in clinical practice and is comparable to the normal clinical cutoff value in high -sensitivity CRP assays (1 mu g/mL). The aptasensor was successfully applied for detection of CRP in Covid-19 patients with spike recoveries between 84 and 102% and RSD from 0.94% to 2.05%.

Automated summary

In this study, an aptasensing method using RNA and Cu-MOF was developed for the detection of CRP. The method showed high sensitivity and selectivity, and it could be performed in both fluorescence and colorimetry modes with lower limits of detection compared to nephelometric techniques commonly used in clinical practice.