Tumour surveillance by microchip
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- The microchips soon to be used for tumour surveillance are barely half the size of your little finger. Source: Becker/TU München
18.12.2011 -
Cancer needs oxygen in order to spread. The scientists at the TU Munich are exploiting this fact in the development of a sensor chip that can form a diagnosis. Once in the body,this will be used to monitor oxygen concentrations in the vicinity of tumours, and warn doctors if a cancer becomes active and is threatening to form metastases.
In the future, the spy that will be employed to keep an eye on cancer tumours will be half the size of your little finger. A team of medical technicians headed by Bernhard Wolf, a professor at the Heinz Nixdorf Chair for Medical Electronics, have manufactured the device using biocompatible materials, and coated it with a special membrane. In doing so, they want to prevent the body from recognising it as foreign and enclosing it in a capsule of tissue, or even rejecting it entirely. Using tiny loops, it is sewn into the body so that it cannot be transported away from the site. Right on location instead of on the outside – the storage mediums being developed in IntelliTuM (Intelligent Implant for Tumour Monitoring) will be placed as close as possible to the cancer site, where they will monitor growth. Data is sent wirelessly to the doctor, who can then decide if treatment is appropriate. The project is being funded over 3 years with 530,000 euros from the Federal Ministry for Education and Research (BMBF; scientists were recently able to demonstrate a first prototype.
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Fewer inspections
“Tumours take the oxygen from the tissue in their immediate environment,” says project manager Sven Becker from the TU Munich, describing the basis for the project. “The reason for this is that blood vessels sprawl relatively uncontrolledly in these locations. The stronger the oxygen depletion in the vicinity of a tumour, the greater its tendency to metastasise.” The oxygen is one of most – but not the only – important indicators. Also planned are measuring instruments for temperature and pH value, as tissue acidification also occurs in the tumour environment.
The newly developed sensor chip transmits the data to a receiving device carried by the patient. This transfers data to the doctor, who can then decide on therapies or surgery. This approach is expected to reduce costs considerably. Health inspections, X-ray investigations and tomography would no longer be necessary, and the tumour would be just as closely observed as ever. Monitoring could also take place after a successful operation; If a new tumour begins to form, the alarm would sound.
Auto-calibrating and biocompatible
Miniature medical technology is a specialty area at the TUM institutes, which, among many other developments, has already developed a pressure sensor for bite splints, to be used in the area of dental technology. IntelliTuM builds on a pilot project in which scientists monitored bone healing in sheep – also focusing on the concentration of dissolved oxygen in the blood at the wound site. The idea comes from basic research in the field of cell-chip systems, which has been undertaken in its own department for many years. These chip systems use living cells as signal transducers, allowing chemosensitivity testing to be performed on tumour cell cultures, for example. In the IntelliTuM project, these chip systems have now been further developed for in vivo use. “We have designed the sensor chip in such a way that it calibrates itself during measurement pauses according to a defined concentration of dissolved oxygen,” says Becker. A biocompatible shell surrounds the electronics, platinum electrodes, radio unit, and battery.
The objective of the BMBF-funded project has been achieved with the prototype; the scientists are currently applying for a follow-up project for clinical validation. “It has worked well in the lab, now we need to bring the technology into the body,” says Becker. Initially, this means equipping sheep or pigs with the sensor, which must be reduced even further in size than for use in humans. “We are aiming for a minimally invasive procedure,” says Becker. “The chip is hoped to become so small that it can be inserted with a biopsy needle.”
In addition, work is being conducted on a miniature drug pump that can deliver chemotherapeutics, on demand, to the tumour site. The Munich-based scientists are also working hard on the energy supply. At this time, the battery in the sensor chip lasts for about nine months; Becker and his team hope to extend this to several years. If everything goes to plan, IntelliTuM could be regularly applied in humans in about ten years.
