Why do living cells switch to DNA

18.07.2002 10:25

Manipulate living cells without destroying them

Axel Burchardt University Communications Department / Press and Information Department
Friedrich Schiller University Jena

Researchers at the University of Jena are developing new laser technology for targeted DNA transfer

Jena (07/18/02) Transferring DNA from one cell to another is not only the basis of cloning and artificial insemination. For years, medical professionals and biotechnologists have been trying to establish new techniques for modifying genetic information around the world. It is intended to carry out gene therapies and similar biotechnological changes. Researchers at the Friedrich Schiller University in Jena have now presented how such a gene transfer can be carried out using a specific laser coupled with a multi-photon microscope without damaging the living cell. Dr. Uday K. Tirlapur and PD Dr. Karsten König from the Center for Laser Microscopy at the Jena University Hospital describe this in their article "Targeted transfection by femtosecond laser", published today (July 18th) in the latest edition of the internationally renowned journal "Nature" ( Vol. 418, pp. 290-291) appears.

In their research, König and Tirlapur from the University Institute for Anatomy II determined how foreign pieces of DNA can be inserted into living mammalian cells without destroying them. The cells continued to develop normally in the microscope cell chambers in which the experiments were carried out. The innovative thing about the Jena Method: The scientists used a near infrared (NIR) femtosecond laser with a wavelength of 800 nanometers. This NIR laser cuts a small hole in the cell membrane for a fraction of a second (16 milliseconds), which then closes again by itself shortly afterwards. The DNA fragments enter the cell through this perforation and accumulate at the predetermined location.

The cell is then programmed to produce certain new proteins. This is shown by Tirlapur and König through the use of an EGFP gene, which encodes a green fluorescent protein. This already known "reporter gene", which glows green after contact with light, guides the researchers to the right place through its color change and proves the success of the DNA transfer. "Our laser process is better than the previously used nanosecond pulsed UV laser techniques," says Dr. Tirlapur self-confident, "because the cell is neither disturbed in growth nor in other development." The native Indian, who has been working at the University of Jena for five years, also considers the use of the femtosecond laser to be the best technology, as the survival rate of the manipulated cells is significantly lower when other lasers are used.

However, the Jena scientists still have to start individually. But together with the Jena high-tech company "JenLab GmbH", the university researchers are working on automating the system. This would make it possible to transfer large numbers of cells in a short time.

There is a huge market for this, because the new technology can be used in many different ways: in cell and molecular biology as well as in the development of new vaccines, in gene therapy and dermatology. In the future, skin disorders in particular could be treated with gene therapy using Jena technology. The procedure can also be used for stem cell therapies. Then it is possible to consciously differentiate - even adult - stem cells into different cell types. But before it can be used in medicine, "greater efforts and financial resources are necessary," says Dr. King. "So it will take a while," says Dr. Tirlapur on the research status of their work. The two researchers also want to modify the method for the plant sector in the future and use it for the development of functional foods.

But first, Dr. Tirlapur is busy answering the numerous inquiries from journalists and colleagues from all over the world. The bottle of champagne will also have to wait a while to be opened until Karsten König has returned from a research stay in the USA, where he was pleased to receive the news of the publication of the Nature article.

PD Dr. Karsten König
Head of the Center for Laser Microscopy
Email: [email protected]
Dr. Uday K. Tirlapur
Email: [email protected]

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