1993, Walt W. Webb, “Developmental Resource for Biophysical Imaging Opto-Electronics”, in Resources for Biomedical Research Technology[1], U.S. Department of Health and Human Services; Public Health Service; National Institutes of Health, page 10:
A new optical force microscopy development scans surface profiles at 10 femtonewton force sensitivity and 10 nm resolution.
2002, Shoji Maruo, Koji Ikuta, Hajato Korogi, “Direct Nanomanipulation Tools for Biological Samples”, in Yoshinobu Baba, Shuichi Shoji, Albert van den Berg, editors, Micro Total Analysis Systems 2002: Proceedings of the μTAS 2002 Symposium, held in Nara, Japan, 3–7 November 2002[2], volume 2, Springer Science & Business Media, published 2012, →ISBN, page 937:
The femtonewton order force-control of the manipulator arm was also demonstrated by adjusting the focal position of the trapped laser beam.
2018, Trevor J. Gahl, Anja Kunze, “Force-Mediating Magnetic Nanoparticles to Engineer Neuronal Cell Function”, in Ioan Opris, Mikhail Lebedev, Ruxandra Vidu, Victor Manuel Pulgar, Marius Enachescu, Manuel Fernando Casanova, editors, Nanotechnologies in Neuroscience and Neuroengineering[3], Frontiers Media SA, published 2020, →ISBN, page 144:
The authors reported operating nanomagnetic forces in the femtonewton range below the thermal fluctuation threshold (Ducasse et al., 2017).
2020, Jing Liu, Zhi-Juan Li, “Optical Tweezers” (chapter 6), in Klaus D. Sattler, editor, 21st Century Nanoscience – A Handbook: Nanophotonics, Nanoelectronics, and Nanoplasmonics[4], volume 6, CRC Press, →ISBN, Introduction, Principle, and Application (section 1), page 201:
As is well known, optical tweezers can trap various objects as small as nanometer-size particles and can exert optical forces with controllable amount at the femtonewton resolution.
