Laser: Precise Printing of Biomaterials

Photo: LIFT method

Transferring biomaterials to a micro-
array chip using the LIFT method;
© Fraunhofer ILT/Aachen

At the Fraunhofer Institute for Laser Technology ILT, an interdisciplinary team of researchers is working on a method for transferring biomaterials and on innovative systems technology.

Now the scientists in Aachen have managed to manufacture a machine for medical and pharmaceutical research based on the laser-induced forward transfer (LIFT) method. The system is to be used mainly for the selective transfer of hydrogels, living cells, and other biomaterials. The first prototype machine, known as LIFTSYS, was recently delivered to the Swiss Federal Institute of Technology in Lausanne EPFL.

The LIFT method can be used whenever tiny amounts of material need to be applied onto receiver substrates with pinpoint precision. One broad field of application for the technology is medical and pharmaceutical research, for instance, where diseases and active pharmaceutical ingredients are studied in specially made test structures. Here it is imperative to apply the precious material selectively and as sparingly as possible onto a receiver substrate. The LIFT method facilitates the transfer of a broad range of materials, such as glycoproteins, living cells, and metals – with high precision and using up a minimum of resources. The Biofabrication Group at Fraunhofer ILT is currently working on further developing complex cell-based in vitro test systems.

The receiver substrate is situated beneath a glass slide bearing the biomaterial to be transferred on its underside and an intermediate titanium absorber layer. A pulsed laser beam evaporates the titanium layer, and the resulting forwards impulse transfers the biomaterial onto the receiver substrate. This laser-based process has no need of a printer head and so it can transfer biomaterials such as RNA, DNA, proteins, and cells regardless of their viscosity. The absence of a printer head also means there is none of the associated sample wastage caused, for example, by feeder lines. This dramatically reduces the amount of material required to carry out an analysis. What is more, the LIFT method can produce spot sizes of 10 µm to 300 µm – which means up to 500,000 protein spots can fit onto a surface the size of a thumbnail. Until now it has not been possible to build up sample material with such precision and efficiency and in such small amounts.

Fraunhofer ILT’s system development resulted in an innovative five-axis machine with motion systems for transfer and receiver substrates. The built-in beam source can be set to the wavelengths 355 nm or 1064 nm, and the focal position, laser power, and number of pulses can be automatically controlled. This enables the user to transfer a wide range of substances, from biomaterials to metals, with the LIFTSYS machine.; Quelle: Fraunhofer Institute