The aim of a new biosensor chip developed at EPFL (The École polytechnique fédérale de Lausanne) is to monitor the concentration of molecules, such as glucose and cholesterol, and certain drugs simultaneously. Being of a small size - only a centimetre long, it is placed under your skin and powered by a patch which is placed on the surface of your skin.  This chip communicates with mobile phone for information transmission.

This chip is realization of a fully implantable device that integrates a microfabricated sensing platform, a coil for power and data transmission and integrated circuits. The device intends to test the biocompatibility of the materials used for the microfabrication. To ensure biocompatibility an epoxy enhanced polyurethane membrane was used to cover the device. It was proved through an in-vitro characterization that the membrane was capable to retain enzyme activity up to 35 days. After 30 days of implant in mice, in-vivo experiments proved that the membrane promotes the integration of the sensor with the surrounding tissue, as demonstrated by the low inflammation level at the implant site.

In order to establish the correct diagnosis and to choose the correct drug dosage amount, medicine should be precise. The main purpose of the scientific researches is to get constant analysis over the longest period possible. A certain number of EPFL laboratories are working on devices allowing it to be done. Biosensor chip is the latest development, created by researchers in the Integrated Systems Laboratory working together with the Radio Frequency Integrated Circuit Group. Sandro Carrara presented it in 2015 at the International Symposium on Circuits and Systems (ISCAS) in Lisbon.

Dr Carrara said “This is the world’s first chip capable of measuring not just pH and temperature, but also metabolism-related molecules like glucose, lactate and cholesterol, as well as drugs. Knowing the precise and real-time effect of drugs on the metabolism is one of the keys to the type of personalised, precision medicine that we are striving for”.

This biosensor chip contains three main components: a circuit with six sensors, a control unit for analysing incoming signals, and a radio transmission module. There’s one more important component - an induction coil, which is used to draw power from an external battery attached to the skin by a patch. “A simple plaster holds together the battery, the coil and a Bluetooth module used to send the results immediately to a mobile phone,” said Dr Carrara.

The researches received very promising results after successful tests of this device in vivo on mice, which took place at the Institute for Research in Biomedicine (IRB) in Bellinzona. They managed to monitor glucose and paracetamol levels without a wire tracker getting in the way of the animals’ daily activities. These successful testing results bring hope that clinical tests on humans could take place in three to five years. Furthermore, the procedure of placing this chip under skin is not that frightening as it may seem – it’s only minimally invasive – the device is implanted just under the epidermis.

There’s a great number of biosensors nowadays. The researching methods and technologies improve giving life to new inventions. Each biosensor has its own purpose: in medicine, biosensors can be used to monitor blood glucose levels in diabetics, detect pathogens, and diagnose and monitor cancer. Environmental applications of biosensors include the detection of harmful bacteria or pesticides in air, water, or food (ie, during food preparation). The military has a strong interest in the development of biosensors as counter bioterrorism devices that can detect elements of chemical and biological warfare to avoid potential exposure or infection. Biosensors can be placed on the human body for monitoring vital signs, correcting abnormalities, or even signaling a call for help in an emergency. In theory, the applications of biosensors are limitless.

Early biosensors used naturally occurring recognition elements that were purified from biological or environment systems. With advances in technology and synthetic chemistry, many biosensor recognition elements used today are synthesized in the laboratory to allow for improved stability and reproducibility of biosensor function. Examples of recognition elements are receptor proteins, antigens, antibodies, enzymes, and nucleic acids. In comparison with the idea of a new biosensor chip created by EPFL they all have significant differences: size, wiring connection etc.

Biosensor chips examples:

• A multidisciplinary Swiss team has developed a tiny, implantable device that instantly analyses the blood before wirelessly sending the data to a doctor.

• Chip–NMR biosensor for detection and molecular analysis of cells

• Tumor biomarker to detect cancer                                                                            

• Handheld high-throughput plasmonic biosensors using computational on-chip imaging