Flexible microneedle array with AuNPs/MXene for visualized electrochemical monitoring of osteosarcoma miR-181b.

Osteosarcoma monitoring lacks highly sensitive and portable molecular detection methods, creating an urgent clinical need. This study develops a highly sensitive and portable biosensing platform (M-Needle-AuNPs-MXene-EC) integrating flexible microneedle (M-Needle) sampling, gold nanoparticle-titanium carbide (AuNPs-MXene) synergistic signal amplification, and electrochemical (EC) detection for precise quantification and visual dynamic monitoring of microRNA-181b (miR-181b) in osteosarcoma tissues. The platform utilizes microneedle arrays for minimally invasive tissue sample extraction and employs AuNPs-MXene composites to significantly enhance the sensing interface conductivity and biomolecule loading capacity. Experimental results show that the conductivity of the AuNPs-MXene composite (10.9 ± 1.1 S/cm) is nearly nine times higher than that of the Ti3AlC2 MAX phase (1.2 ± 0.12 S/cm). Under optimal conditions, the sensor achieves a linear detection range for miR-181b from 1 aM to 100 pM, with a detection limit as low as 0.34 aM, and exhibits favorable selectivity, high reproducibility and long-term stability of up to 60 days. The integrated visual interface enables real-time monitoring of the detection process and intuitive output of results. Validation using clinical tissue samples demonstrates that the platform can effectively distinguish between osteosarcoma patients and normal controls (p < 0.05), with an area under the receiver operating characteristic curve (AUC) of 0.889. This integrated platform combines minimally invasive sampling, efficient signal amplification, and visual detection, offering a novel point-of-care tool for dynamic monitoring of osteosarcoma.