Force for good

Atomic force microscopy systems are used to understand soft matter and biological systems at the molecular scale

Researchers at the University of Sheffield are using atomic force microscopy (AFM) systems to further understand soft matter and biological systems at the molecular scale in the Hobbs SPM Group in the Department of Physics.

Dr Nic Mullin is a senior experimental officer in the SPM Group of Professor Jamie Hobbs in the Department of Physics & Astronomy at the University of Sheffield. His research is based around instrument development for scanning probe microscopy for the study of soft matter and biological systems at the molecular scale.

As well as applying existing methods and instrumentation, the group have the added challenge to develop new equipment and protocols to allow the study of different samples at higher magnifications applying new detection systems.

This has been formalised (for biological systems) in the Imagine: Imaging Life initiative, which brings together electron microscopy, super-resolution optical microscopy and AFM to study living systems.

One of the major goals is to use AFM to provide information that complements the information garnered from the electron and super-resolution optical microscopies.

The group has many years of experience using AFM. For example, having the resolution to see not just where molecules are and how they are arranged, but what their conformation is, is vital for many of the things they are interested in.

Being able to resolve features with sufficient signal to noise ratio in real space is also a huge plus and means that they are not restricted to looking at systems that are static in time or spatially ordered.

Also, the ability to make mechanical measurements, either as a contrast mechanism, or as an indication of structure/function is really useful.

The ability to do all this under relevant conditions and without too many restrictions on sample preparation makes AFM a fantastic tool for the research of the group. It makes selection of the appropriate systems vital in the quest of the group to retain a position of leadership in the field. Choosing to work with JPK Instruments on this has proved to be a successful choice.

Working with an expert

Mullin takes up the story about the group’s use of JPK’s NanoWizard AFMs and their integration with the other microscopies, saying: “We work extensively with collaborators using transmission electron microscopy and super-resolution optical microscopies, often using these techniques to obtain complementary information. We use one of our JPK systems for correlative AFM-STORM.

“The performance of our JPK NanoWizard systems is exceptional and the user interface is intuitive and well designed. The integration with optical microscopy is extremely good. The system was clearly designed to work with biological samples in liquid. This really shows. For example, it's really straightforward to keep everything clean and free from contamination. The other big benefit is the company itself ­ we are interested in developing and optimising our experiments, and JPK really supports us with that, providing tweaks, workarounds, hacks and information that enable us to expand our capabilities and the kind of things we can study.”

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