The clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein (Cas) (CRISPR/Cas) systems have recently emerged as a powerful molecular biosensing tool based on their collateral cleavage activity due to their simplicity, sensitivity, specificity, and broad applicability. However, the direct application of collateral cleavage activity for in-situ intracellular detection is still challenging. Here, we debut a CRISPR/Cas-assisted nanoneedle sensor (nanoCRISPR) for intracellular adenosine triphosphate (ATP), which avoids the challenges associated with intracellular collateral cleavage by introducing a two-step process of intracellular target recognition followed by extracellular transduction and detection. ATP recognition occurs by first presenting in the cell cytosol an aptamer-locked Cas12a activator conjugated to nanoneedles; the recognition event unlocks the activator immobilized on the nanoneedles. The nanoneedles are then removed from the cells and exposed to the Cas12a/crRNA complex, where the activator triggers the cleavage of a ssDNA fluorophore-quencher pair, generating a detectable fluorescence signal. NanoCRISPR has an ATP detection limit of 246 nM and a dynamic range from 1.56 μM to 50 μM. Importantly, nanoCRISPR can detect intracellular ATP in 30 min in live cells without impacting cell viability. We anticipate that the nanoCRISPR approach will contribute to broaden the biomedical applications of CRISPR/Cas sensors for the detection of diverse intracellular molecules in living systems.

Mapping the molecular composition of tissues using spatial biology provides high-content information for molecular diagnostics. However, spatial biology approaches require invasive procedures to collect samples and destroy the investigated tissue, limiting the extent of analysis, particularly for highly functional tissues such as those of the brain. To address these limitations, we developed a workflow to harvest biomolecules from brain tissues using nanoneedles and characterise the distribution of lipids using desorption electrospray ionization mass spectrometry imaging. The nanoneedles preserved the original tissue while harvesting a reliable molecular profile and retaining the original lipid distribution for mouse and human brain samples, accurately outlining the morphology of key regions within the brain and tumour lesions. The deep neural network analysis of a cohort containing 23 human glioma biopsies showed that nanoneedle samples maintain the molecular signatures required to accurately classify disease state. Thus, nanoneedles provide a route for tissue-preserving spatial lipidomic and molecular diagnostics.