Rational MOF carrier engineering for tunable ATP detection

Adenosine triphosphate (ATP) serves as a critical biomarker in clinical diagnosis and microbial quantification. Given the substantial variation in ATP levels among biological samples, developing assays with high sensitivity and a tunable linear range is essential for ensuring broad method applicability. In this work, we propose a carrier engineering approach that modulates the carrier's morphology and dosage to rationally tune the sensitivity and linear range of ATP detection, based on the well-established zeolitic imidazole framework (ZIF)-mediated ATP sensing. Specifically, micrometer-sized methylene blue (MB)-loaded ZIF-8 (MB@ZIF-8) carrier with polyhedral morphology and nanometer-sized MB@ZIF-8(CTAB) carrier with cubic morphology were prepared, the latter using cetyltrimethylammonium bromide (CTAB) as a morphology modulator. This morphological engineering enables tunable probe encapsulation, with larger MB@ZIF-8 carrier particles showing a higher loading capacity than smaller MB@ZIF-8(CTAB) particles. On this basis, the number of carrier particles in sensing system was regulated by controlling carrier dosage. Systematic investigations reveal that enhanced MB loading in individual carrier particles improves detection sensitivity through amplified signal output, while increased number of carrier particles involved in the reaction broadens the linear range by providing more stimulus-responsive sensing units. These results were consistently observed in both fluorescence and photoelectrochemical readout modes. The constructed sensing systems have exceptionally wide and adjustable dynamic ranges (spanning 4 to 6 orders of magnitude) and high sensitivity (detection limit as low as sub-picomolar level). This study has developed a novel carrier-centric regulation method that enables system-level modulation of sensing performance, providing a new avenue for highly adaptable ATP detection.