Optical Atomic Force Microscopy

Lead Research Organisation: University of Bristol
Department Name: Physics


Atomic force microscopy (AFM), is a state-of-the-art imagining system that uses a sharp probe to scan backwards and forwards over the surface of an object. The probe tip can have atomic dimensions, meaning that AFM can image the surface of an object at near atomic resolution. However, the limitation of these systems is that, just like with a record player, the needle has to be held by a mechanical arm or cantilever. This restricts the access to the sample, prevents the probing of deep channels or indeed any surface that isn't predominantly horizontal.Our idea to hold the tip of an AFM in an optical beam, without any mechanical constraint. Optical tweezers use the momentum of light beams to trap and move individual spheres, here we will use them to hold and control the AFM tip - without need for any mechanical fixing.We have shown the use of data-projector technology to shape light beams to hold many objects, and that this can give control over a simple probe. We have also shown that high-speed cameras can measure the force acting on the probe with 100 times greater sensitivity than most AFMs. Finally we have shown that the interface of optical tweezers can be made intuitive, e.g. controlled by iPhone!In this project we will develop our use of video game graphics cards for high-speed control and force-feedback to give the user a tactile interface, perhaps utilising the professional equivalent of a Wii motion controller. We will automate a scanning system so that full surface images will be obtained. We will create new probe types, functionalised to give various contrast enhancements. Initially our images will be of standard AFM test samples, but beyond this benchmarking we have budgeted for visits by leading biophysical researchers to test our new approach in their real applications. These range from T-cell interactions to differentiation of stem cell .The project is ambitious breaking new ground in both tweezers, AFM and imaging technologies but we believe the track records of the collaborating teams make success possible.

Planned Impact

Who will benefit from this research? The impact of this research will be in the life sciences where the optical AFM will open up fields of investigation inaccessible with conventional AFM. This will be important for studying cellular surface structure and the effects of external stimuli. The optical AFM represents a major development in AFM and its development will also impact materials science. The optical AFM will also drive the advancement of associated technologies such as 3D force measurements, control of nanotools in 3D, force feedback in 3D, and thermal noise reduction feedback. Commercialization of optical AFM is an achievable impact. We have commercialization experience through our spin-out company Infinitesima Ltd. Commercial interest also exists in the component manufacturers such as Boulder Nonlinear Systems, Hamamatsu, laser (Coherent, M2) and microscope supplies (Olympus, Zeiss, and Nikon). Similarly, AFM companies, particularly those involved also in optical tweezers such JPK, will also have a keen interest. The probes for the optical AFM are, of course, of a different specification and structure, and the manufacture of these offers another commercialization opportunity including for another one of our spin-out companies, NanoTrix. Society will benefit through the research that will be undertaken with this revolutionary instrument both as a result of better understanding of cellular processes but also through the training in state-of-the-art instrumentation development. How will they benefit from this research? The potential impact on stem cell therapies and cancer cell research on the nation's healthcare is immense, and a lead in this area would have a major wealth-generating impact. A scientific lead that translates into healthcare therapies and devices could grow a new economic activity increasing UK competitiveness. The ability to identify diseased cardiac cells, and repair and restore normal function through stem-cell treatment of infarcted hearts and provide new directions in cancer therapy would have major impact in the reduction of the burden on the healthcare system of the chronically ill. Similarly, this new 3D imaging method will provide new knowledge of structure and behaviour of retinal cells which will be of benefit to those suffering from retinal degradation. The development of the optical AFM with a highly intuitive multi touch interface for the manipulation of living cells and the measurement of interaction forces in a controlled environment will bring a new tool and skill cell researchers. The project is highly interdisciplinary involving physics, physiology, and clinical medicine. Exposure to this environment will have a major positive impact of the outlook and skills of the research assistants involved in the project. It not only gives specific experience and knowledge in fields outside their individual disciplines it also encourages and enhances their open-mindedness to interdisciplinary research. What will be done to ensure that they benefit from this research? The interdisciplinary nature of this project provides natural routes to many of the potential beneficiaries of the project. We will develop a dedicated website as we have done for the holographic assembler, and run dedicated workshops in the use of this optical AFM. We will engage with the public on open days and SET activities. In the past nine years we have worked with the University's enterprise team for exploitation through patenting and spin-out companies. The direct links to the NHS will ensure that the healthcare benefits will reach the appropriate communities and will be optimize for the full impact of this research.


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Description I have succeeded in removing the constraint of atomic force microscopy (and all scanning probe microscopies) that the sample should be planar because the AFM cantilever and probe scans in a plane. By using, a micro/nano tool as an AFM probe and controlling it with holographic tweezers, we are able to scan around a three-dimensional structure with 10s of nanometres resolution. We are now working on scanning multiple probes simultaneously.
Exploitation Route The potential use of such a new characterisation tool would have the same imperative for industrial research laboratories as for academic laboratories. An exploitation route could be through the holographic tweezers Cube now marketed by Boulder Nonlinear Systems developed in the joint collaboration with Prof Padgett's Group (Glasgow) on the Basic Technology grant"Dynamic Holographic Assembler".
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Digital/Communication/Information Technologies (including Software),Electronics,Energy,Environment,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

Description This project created a new type of scanning probe microscope and technique which has applications in all areas of research development where structures under investigation are not planar, i.e., most situations and samples. The findings are embedded in the techniques for 2PP micro/nano probe tool development, the new EM field-force simulation techniques to design and fabricate the tools require for controlled imaging 3D structures over 4p directions, and the algorithms for scanning and imaging over a 3D object at extremely low (10s fN) constant force. An exciting unexpected outcome, which facilitated the low constant force AFM-like imaging in 3D was the nature of the 'optical' springs developed. Springs with tailored varying spring constants, including even changing in sign (!), dependent on the degree of compression can be designed and fabricated the curvature of the micro/nano tools. Since such spring do not exist in material springs, the possibilities of applications are fantastic.
First Year Of Impact 2013
Sector Agriculture, Food and Drink,Energy,Healthcare,Pharmaceuticals and Medical Biotechnology
Impact Types Economic

Description Talk at Bristol Scientific Club 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact I gave a presentation which covered the use of holographic tweezers to control 3D-printed micro tools as a 3D optical AFM. The audience was from a wide science and engineering background and I believe the talk was received with enthusiasm. One result was that I was invited to join this prestigious club.
Year(s) Of Engagement Activity 2017