iPad used as 'optical tweezers' to manipulate particles

With a faster processor, longer battery life, and, in case you had not heard it bellowed from the roof tops over the past month or so, two cameras, the iPad 2 is coming and is being proclaimed as nothing short of a minor miracle.

Now the Apple tablet will be able to add another string to its bow, with the ability to remotely manipulate particles in real time.

Of course this is not likely to feature on the spec sheet, so before Jobs’ Mob proclaims that this is its idea, it should be said that this is the work of a group of researchers at the universities of Bristol and Glasgow.

The team has developed software for what ‘optical tweezers’, ingeniously utilising the iPad alongside existing technology for manipulating small particles via laser beams, a practice widely used in molecular biology.

Control of particles from a computer has often been rather tricky according to the scientists, with the traditional mouse or joystick approach having downsides in ease and accuracy of use.

Research published today in Journal of Optics shows how easier manipulation of particles can be performed through an “elegant and intuitive interface” 3D control system, using the iPad’s touch screen technology.

The iPad’s multi-touch allows the researchers a range of techniques for moving the particles around which users of many of Apple’s products would be familiar with, such as pinching the screen or tilting in order to move single particles in any direction including rotating them.

Our optical tweezers system lets us move multiple objects around in 3D at the same time- but our mouse-driven computer limited how much use we could make of that,” Richard Bowman, the paper’s author told TechEye.

“The iPad gives us full 3D control of each object, in a really simple, intuitive interface.  

“It’s worth mentioning that the iPad isn’t our first multi-touch device; the Bristol team built a multi-touch table (a bit like the Microsoft Surface, I believe) a couple of years before the iPad came out.

“That got us thinking about new interfaces, and when the iPad came along we realised it could do a lot of what the table could do, but with the convenience and simplicity of a commercial device.

“Also, the small size and wireless connectivity have been useful- allowing it to be moved around the lab.

According to Bowman the software is particularly useful when used to move multiple objects, overcoming problems with previous methods: “It’s great when you need to move two objects at the same time, but in different directions,” he said. “Without multi-touch, that would have either required two joysticks, which is a bit fiddly, or a pre-programmed trajectory for each particle.

“Also, it’s really handy when we need to align the optics, because we can pick it up and put it somewhere convenient. It saves a lot of stretching to see the computer screen and the lab bench at the same time as we can’t have the computer right next to the bench for laser safety reasons.”

With the wireless connectivity that the iPad uses, the device used to monitor and control the ‘tweezers’ does not risk contamination with wires.

“Our iPad-based interface allows intuitive control of a holographic optical tweezers system using a dedicated application on the iPad and a modified version of our tweezers’ control software running on a host PC,” the researchers wrote.

“The interface is responsive and easy to use, so even inexperienced users can trap particles, move them around and translate the microscope stage.”

See video below for proof that there is more to the iPad than Angry Birds:


“There’s a few things where the multi-touch really comes into its own,” Bowman tells us, “for example when we want to manipulate micro-rods, which the researchers in Bristol are using to try to make tools, you need several traps on each rod, and the touch interface is the perfect way to control it.

“Also, we have collaborators in the chemistry department who are interested in controlling crystal growth – and one thing we’d like to do is direct several crystals at once. That will really only be possible with the iPad.”