Fiber optic nanomechanical probe for single-cell mechanics analysis

Ultrasensitive nanomechanical instruments, e.g., atomic force microscopy (AFM), can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes. However, these instruments are limited because of their size and complex feedback system. Here, we demonstrate a miniature fiber optical nanomechanical probe (FONP) that can be used to detect the mechanical properties of single cells. The stiffness matching of the FONP and sample can be realized by customizing the microcantilever’s spring constant. As a proof-of concept, three FONPs with spring constants varying from 0.421 N/m to 52.6 N/m by more than two orders of magnitude were prepared. The Young's modulus of heterogeneous soft materials, such as polydimethylsiloxane, onion cells and MCF-7 cells, were successfully measured. FONP has made substantial progress in realizing basic biological discoveries, and our strategy provides a universal protocol for directly programming fiber-optic AFMs.