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When the body receives an implant, a series of physical, chemical and biological processes related to the integration of the new element are triggered in the recipient. Sometimes infections, clotting, or local loss of tissue occurs and implants do not perform well. One challenge in the field of bioengineering is to increase tolerance of implant biomaterials and get the body to accept them quickly.

“If we implant an artificial material in the body, we want it to be recognised as ‘self’,” says José María Manero, a researcher with the UPC’s Biomedical Engineering Research Centre (CREB), summing up the scientific objective that drives his work. One way to achieve this is to “modify the surface of the biomaterial – a prosthesis, for example – by coating it with organic molecules (proteins, peptides or nucleic acids) to improve compatibility with the recipient and make the biomaterial an active element in the regeneration of the tissue or organ we want to recover,” says Manero. This technique, known as biofunctionalisation, is based on an empirically observed process: proteins adhere to the surface of implants and nearby cells then migrate and bind to these proteins. The idea is to choose proteins that will attract the right type of cells, ones that have the ability to grow and create different tissues (bone, nerve and adipose). The particular protein chosen clearly determines the result.

“We know that if we put fibronectin or collagen on a titanium implant, we can induce growth of bone tissue,” says Manero. But that is not all that needs to be accomplished. Manero says that “apart from working biologically, the solution must last.” One problem is that the proteins degrade over time. The Biomaterials, Biomechanics and Tissue Engineering Group (BIBITE) of the CREB, to which Manero is attached, is looking for a way to prevent this by using only enough protein fragments (sequences) to get cells to adhere to the surface of the implant. This slows down degradation. The drawback is that without the complete protein, the growth rate of adherent cells is reduced. The research is now focused on finding protein sequences that do not affect cell growth.

Implants sometimes fail because they become contaminated with bacteria during surgery. To address this problem, the BIBITE group is looking at ways to introduce antibiotics or molecules with antimicrobial properties in biomaterials. José María Manero thinks these applications could be brought to market this decade and says this would lead to “a major improvement in quality of life for many people.”

The human body is a very complex system that is full of information and is continuously sending signals. But how can we interpret them correctly? And how can we distinguish significant signals from those which are not? The UPC’s Biomedical Signal Processing and Interpretation Group – led by Raimon Jané, who is attached to the Institute for Bioengineering of Catalonia (IBEC) – is working to answer these questions by bringing information and communication technologies (ICT) to medicine.

“Conventional diagnostic techniques look at fragments of information; we focus on intelligent interpretation of physiological signals that allows us to obtain clinical information that would otherwise go undetected,” says Jané. The research group is focusing on advanced processing of biosignals as way of improving early diagnosis and monitoring of cardiac and respiratory diseases and sleep disorders, conditions that are often linked. For example, symptoms such as snoring, apnoeas and hypopnoeas, and respiratory pattern can reveal a great deal about cardiorespiratory function. Conventionally, observation tends to focus only on intensity of snoring, the number of apnoeas and hypopnoeas, and respiratory rate. The team led by Jané is working to improve diagnosis based on analysis of respiratory sounds, non-invasive classification of obstructive and central hypopnoeas, and modelling of respiratory pattern and snoring.

Collecting information is important, but the key is to make sense of this data by looking at it in relation to other signals of different types. “This way we get a broader picture of the state of the patient; we discover causes and effects and generate new medical knowledge because we study interrelations that have never been captured before,” says Jané. Advanced information processing techniques are crucial as a tool for identifying significant connections. The approach also simplifies diagnosis. According to Jané, “a few biosignals can provide more information than many classical parameters.”

The researchers work closely with hospitals. “We want to address the needs of doctors in their everyday work. This means dealing with real cases, which opens the door to the development of new medical equipment,” says Jané. Advances lead to increased efficiency, faster and more accurate diagnoses, and improved therapeutic treatment.
A socially valuable aspect of the new methods is that in the medium term they could bring about a paradigm shift in some medical procedures.

The possibility of using portable devices to monitor patients and perform advanced tests opens the way to sophisticated care in the home setting. This would benefit patients and have a positive impact on the health system, where costs are under scrutiny because of the difficult economic situation.

For some years, robots have also been playing a significant role outside assembly lines, in areas such as human health. The UPC’s Intelligent Robotics and Systems Group, which is attached to IBEC, focuses precisely on this area. According to Alícia Casals, the group has shifted its orientation from industrial robotics to services, and finally to providing care for people. “Working in industry limited our research in some ways. In contrast, the health sector has opened up a range of opportunities,” she says. There is a fundamental difference between the two fields: “In factories there are barriers between people and robots for safety reasons, whereas in the world of health, the patient and the machine have to be in contact.”

In addition to working on ways to support surgery, the group participates with other partners in the HYPER project, aimed at using robotics to help people with motor disabilities gain as much autonomy as possible. The research focuses on developing limb orthotics that patient can activate at will. Robotic orthotics incorporate models of human movement to ensure that they function properly. In conceiving and designing assistive robotic devices, a broad range of needs must be taken into account. Casals stresses that “each person is unique and requires an individualised solution.” When the body will never again be able to make a particular movement, complete mechanical assistance is necessary. Rehabilitation, on the other hand, requires a sophisticated system that progressively modifies the level of assistance in an intelligent way. “If at the start of the process you can’t keep your body upright, the robotic system must support your entire weight, but the level of assistance needs to be gradually reduced. The system must do only what you can’t; otherwise, recovery won’t happen,” says Casals.

It is not desirable for the robot to do all the work involved in performing an action. If the patient is a passive participant and makes no effort, the brain’s ability to execute the action will be inhibited. “We can also design a robot to stimulate you, slow you down, or even make it more difficult for you to perform an action – a device that forces you to make an effort. It all depends on the therapist’s instructions,” says the researcher. These strategies improve the patient’s physical ability and, indirectly, the brain’s ability to drive the action.

Many directions are open to the group led by Alícia Casals as they continue to explore the role robotics can play in this field while engaging in an ongoing dialogue with doctors, neurologists, therapists specialising in neurorehabilitation, and psychologists. “We have to advance empirically as we run into problems,” says the researcher. In the field of bioengineering there are no definitive solutions, only a series of challenges that need to be tackled based on an interdisciplinary approach.