Spatial tumor biopsy with fluorescence PCR microneedle array

Biopsy is the gold standard for tumor diagnosis, as this technology provides highly detailed and reliable information on tumorigenesis and progression. Resembling the discrete wettability of desert beetles, in this study, a fluorescence polymerase chain reaction (F-PCR) microneedle array (MNA) platform is developed for efficient spatial tumor biopsy. This MNA is fabricated by the coupled strategies of bottom-up self-assembly and top-down photolithography; it comprises a hydrophobic silica nanoparticle-assembled substrate and graphene aerogel-hydrogel hybrid microneedle peaks. Benefitting from the hydrophilicity and absorption capacity of its graphene hybrid microneedle peaks, MNA can easily penetrate tissue specimens and collect tumor nucleic acid biomarkers stereoscopically. In addition, because of the discrete wettability of the platform, both tissue fluids and PCR liquids can be easily removed from the substrate, and each microneedle peak is similar to an independent island for directly conducting F-PCR reactions for tumor marker discovery. Based on these advantages, the F-PCR-MNA platform is demonstrated to be ideal for detecting DNA biomarkers of lung carcinoma in standard solutions, mouse tissue samples, and clinical specimens, thus indicating its practical potential as an innovative tumor biopsy system.