Fiber-tip polymer clamped-beam probe for high-sensitivity nanoforce measurements

Area of Science:

• * Micro/nanotechnology
• * Materials Science
• * Biomedical Engineering

Background:

• * Precise force control and measurement are crucial for micromanipulation, biological studies, and material science applications.
• * Existing methods for micro-force sensing often lack the required sensitivity or are bulky.
• * There is a need for compact, highly sensitive sensors for in-situ force measurements.

Purpose of the Study:

• * To develop and demonstrate a novel micro-force sensor for examining biological and material samples.
• * To achieve ultrahigh force sensitivity and a low detection limit for micro-scale force measurements.
• * To explore the potential for creating small-footprint atomic force microscope (AFM)-like devices.

Main Methods:

• * Fabrication of a fiber-tip-polymer clamped-beam probe micro-force sensor using femtosecond-laser-induced two-photon polymerization (TPP).
• * Finite Element Method (FEM) simulations were used to optimize the sensor's structural design and predict its static performance.
• * Experimental characterization of the sensor's force sensitivity, detection limit, and measurement range.

Main Results:

• * The fabricated micro-force sensor demonstrated an ultrahigh force sensitivity of 1.51 nm/μN and a detection limit of 54.9 nN.
• * The sensor achieved an unambiguous measurement range of approximately 2.9 mN.
• * Successful measurement of Young's modulus for polydimethylsiloxane, a butterfly feeler, and human hair.

Conclusions:

• * The developed fiber-tip micro-force sensor offers the smallest force-detection limit in direct contact mode reported to date, comparable to AFM.
• * This technology enables high-precision biomedical and material science examinations.
• * The fabrication method using TPP opens new avenues for complex fiber-integrated polymer devices and compact AFM realization.