Home
In Depth
Jack of all trades

Jack of all trades

21 Nov 2013 by Evoluted New Media

Microscope design has traditionally been based on the concept of relatively closed systems to meet the requirements of a limited number of applications. The advent of the open source concept of frame design with potentially limitless applications is set to radically change how we use and think about microscopy…

The study of cell biology produces a vast amount of information on cell activity, and provides invaluable insight into many research areas such as drug discovery and developmental biology. Advances in the field are driven by the wide ranging microscopy-based techniques that allow the observation of cellular activities. Live cell imaging was pioneered at the beginning of the 20th century and is used today by researchers to study real-time cellular events, for example in response to the addition of a potential therapeutic compound. Such live cell imaging requires the use of an inverted microscope, which has the light source and condenser above the stage pointing downwards, with the objectives and turret below the stage pointing upwards (Figure 1). Invented in the 1850’s these microscopes permit the observation of living cells or organisms at the bottom of a large container such as tissue culture flasks, providing more natural conditions than conventional upright microscopes which normally require glass slides. The inverted microscope frame today forms an essential base upon which to build wide-ranging microscopy systems for a variety of live cell imaging applications.

Up until a few years ago, such microscope frames were sold as dedicated systems with most modules required for specific tasks already integrated, intended for a limited range of applications. Access to the frame’s light path to alter the microscope system for other uses required a certain level of engineering expertise to dismantle the apparatus and modify the hardware.

[caption id="attachment_35882" align="alignright" width="200" caption="Figure 1: The IX83 inverted microscope frame."][/caption]

As most microscope users do not have this level of engineering expertise, adaptable microscope systems have been out of reach for most researchers, meaning that laboratories needed to buy in a range of dedicated systems to meet all their research requirements.

Challenging these constraints, Olympus has developed a new open source microscopy concept with the creation of the IX3 range of microscope frames designed around an accessible infinite light path, allowing optical modules to be interchanged. These ‘modular microscopes’ enable the user to mould the microscope to fulfil diverse requirements. The frames are built around a swappable deck design similar to a chest of drawers; interchangeable modules fit into the deck and can be easily slipped in and out of the light path as required (Figure 1). As infinite light paths are parallel, inserting complex optical components does not bend the light, so there are no errors from optical aberrations.

Open source microscope frames can be easily optimised for any application, from routine observation through to the specialised requirements of advanced imaging technologies. With such an accessible light path, these frames allow any user to re-structure the microscope to suit the aims of the experiment.

A range of optical modules are currently available, and this collection is sure to expand as the concept of the open source microscope takes hold. Multiple combinations of modules can be chosen so that users can mould the components to best suit their workflow.

[caption id="attachment_35924" align="alignleft" width="200" caption="Figure 2: Fluorescence capture of Huh7 cells is achieved here using separate filter positions, and merged to form a multichannel image. The fluorescence cube turret module enables multichannel images - lysosomes in green, mitochondria in red and cell nuclei in blue."][/caption]

When using fluorescence for example, the user can insert a fluorescence filter turret module into the infinite light path and multichannel imaging (Figure 2) can be achieved using separate filter positions. One example of when this is useful is in the specific identification of various molecules labelled with different fluorophores, enabling precise localisation and transport studies. Such filter turrets can incorporate up to eight filter positions which can be easily switched without the use of tools.

The addition of a camera mount (C-mount) allows access to components such as detectors and light sources that can be directed into the infinite light path. This can enable the use of an additional laser for more advanced techniques such as fluorescence recovery after photobleaching (FRAP) experiments. This technique is particularly useful for studies of cell membrane protein binding and diffusion (Figure 3). When used with the fluorescence filter turret module, the connection of an extra camera via the C-mount produces a system optimised for dual camera observation. This is ideally suited for brightfield observation of coloured specimens in parallel with fluorescence microscopy. A monochrome camera attached to the right side port module can visualise fluorescence while a colour camera on the standard camera port visualises brightfield.

Such frames are the ideal basis for a variety of high-end imaging systems, such as confocal laser scanning microscopy or high-content screening. Figure 4 shows a semi-confocal image obtained with a disc-scanning unit.

The benefits of the open source frame design are far-reaching, and set to revolutionise the way we perceive microscopy. In situations where multiple users depend upon a single microscope to perform a diverse range of applications the open source frame concept really comes into its own. In a shared microscopy suite for example, each user must compromise with a single restricted instrument. In place of this, an open source system with a choice of different modules allows each user to swap in their required modules at the start of the session, and the microscope is instantly optimised for the experiment at hand.

[caption id="attachment_35926" align="alignright" width="200" caption="Figure 3: FRAP image of HeLa cells – Open source IX3 frames can be readily modified for this advanced imaging technique – cell nuclei in blue, cytoplasm in green and actin in red."][/caption]

In addition to the components designed byOlympus, the possibility of integrating optical modules designed by third party vendors, and even custom-made modules, makes the applications of the open source frames potentially endless. Prior Scientific, for example, has already released its high-speed filter wheel module designed specifically for the range, which is mounted into the frame deck using a support known as the Breadboard platform. Utilising this platform along with custom components, users can customise the microscope according to their specific needs, now and in the future; truly capitalising on the open source frame concept.

Laying the foundations for the future, the open source frame design is changing microscopy, as systems of integrated components can now be moulded and optimised for many applications. Access to the infinite light path allows rapid and effortless switching between applications such as brightfield, fluorescence and dual camera imaging, without specific engineering knowledge or tools. This modular concept allows customisable microscope systems to grow alongside the evolving demands of any life science research project.

Perhaps one of the most exciting aspects of this concept is handing over system design to the end user. Free from constraints, how will the microscopy community respond and develop the optical modules and microscope systems of the future? The open source concept is certainly set to push the boundaries of technology forward and advance the speed at which microscopy moves into the future. What will you discover?

[caption id="attachment_35927" align="alignleft" width="200" caption="Figure 4: An Obelia stained with GFP and DAPI, using a semi-confocal observation method with a disc-scanning unit."][/caption]