Optical Tweezers Feedback

The nanoprobe is a free-floating 3D force probe for single molecule research.  The unique active feedback sensor tracks and controls the position and movement of the nanoprobe. Additionally, fast and dynamic force measurement of multiple objects is enabled by selective read-out of active pixels within the sensor array.





Technology to manipulate and monitor on the nanometre scale is fundamental to biological research, as well as micro and nano fabrications methods. The nanoprobe, coupled with an advance in fast readout CMOS sensors to provide the unique ability to track multiple objects with accuracy exceeding any conventional tweezers apparatus.

The nanoprobe project aimed to marry the attributes of mainstream optical tweezers technologies with scanning force microscopy. This resulted in a free-floating optical imaging and force probe instrument, with nanometre and sub-piconewton resolution.

The nanoprobe feedback sensor is a custom designed CMOS active pixel sensor with a fast field programmable gate array (FPGA). The FPGA, which controls the sensor readout, enables readout of one sample, while a following sample is accessed from the detector. This greatly increases read-out time and mitigates effects of thermal radiation. 


  • Using a uniquely customised active pixel sensor (APS) array, the feedback sensor is able to selectively read-out pixels grouped into regions of interest (ROI). Each ROI actively monitors and tracks an object trapped by the optical tweezers.

  • The feedback sensor is able to track multiple objects, each within their own ROI, simultaneously and at high speed.

  • Fast read out (10kHz) and micro second acquisition times means the sensor is capable of discerning and compensating Brownian motion.

  • Forces at the nanoprobe tip are measured with pico-Newton accuracy.

  • Position of the nanoprobe tip is measured with nanometre accuracy.   


  • The feedback sensor has been designed primarily for use in conjunction with the optical tweezers nanoprobe.

  • The feedback sensor is also highly suited to micro- and nano-based applications such as scanning probe microscopy, molecular force measurement, and micromanipulation.


Optical Tweezers

Patent Information:
Country Serial No.
United States 11/658026
European Patent Office 5760749.1
For Information, Contact:
Elizabeth Bain
IP Manager
STFC Innovations
+44 (0) 1925 60 3680
05.k. Nanotech. (physical science)
06.b. Biology/Biotechnology
06.d. Micro- & Nanotech. (bioscience)