Science & Tech

Biorobotic Heart That Beats Like a Real One

Ellen Roche, senior author and MIT biomedical engineer, says the simulator is a great tool for researchers studying different heart valve conditions and interventions. She believes it could serve as a surgical training platform for physicians and medical students, allow engineers to study new designs, and even help patients better understand their own diseases and potential treatments.

Before new treatments are applied to humans, they undergo rigorous testing in heart simulators and animal models. However, current heart simulators do not fully reflect the complexity of the heart and have a shelf life of 2-4 hours. Animal studies are expensive and time-consuming, and the findings are not always transferable to humans. The biorobotic heart, which has a shelf life of months, could overcome these disadvantages by being a less expensive method.

The researchers focused their studies on mitral valve disease, a heart valve disease in which the valve between the left heart chambers does not close properly and blood flows backwards through the valve. This condition, which affects approximately 24.2 million people worldwide, can cause shortness of breath, swelling in the limbs, and heart failure. Given the complexity of the valve structure, the surgeries to correct the disorder are quite complex. Therefore, the need for effective technology and precise surgical techniques is of great importance. The team replaced the heart muscle in the left chamber with a soft robotic pump system made of air-powered silicone. When inflated, the system pumps artificial blood through a fake circulatory system by bending and squeezing the heart like real heart muscle, simulating the beating of a biological heart. When the researchers damaged the mitral valve in the biorobotic heart, the valve showed the characteristics of a leaky heart valve. Cardiac surgeons then repaired the damage using three different techniques: fixing the flailing valve leaflet tissue, replacing the valve with a prosthetic valve, and implanting a device to help the valve leaflet close. All three techniques were successful, restoring pressure, flow, and heart function to normal.

The system allowed the research team to collect real-time data during the surgery. The artificial blood used was clear, allowing direct visualization of the procedure. It was also observed that this system is compatible with current imaging technologies used in clinics. In the future, it is aimed to optimize the current biorobotic heart system by shortening the production time and extending the shelf life.

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A Sensor That Makes Parkinson's Patients Walk More

Parkinson's disease, which is caused by the loss of nerve cells in a part of the brain called the substantia nigra, reduces the amount of a chemical called dopamine that helps regulate movement, and often causes tremors, slow walking, and balance problems that can lead to falls. To overcome these symptoms, researchers at Physio Biometrics in Montréal, Canada, developed a sensor called Heel2Toe, which is attached to the inside of shoes. When the user walks forcefully (a movement from heel to toe by pressing on the heel of the foot), it sends a signal to a smartphone via Bluetooth, which makes a "beep" sound. To test the sensor, experts from Physio Biometrics in Montréal and McGill University followed 21 people with Parkinson's who had walking problems but could walk without a cane. All participants had five sessions with a physiotherapist and were given a workbook with tips for balanced walking. Fourteen of them were also given the HeelzToe sensor and told to clip it to their shoes while walking for at least 5 minutes twice a day. After three months, 13 of the 14 participants wearing the sensor had walked further on a six-minute walk than they had at the start of the study. None of the participants who received only physiotherapy sessions and a workbook showed a similar improvement. Forty percent of those using the sensor said they were pleased with the improvements they had made in their walking.

The team notes that the brain loves to be rewarded, and once the beep of the device after each powerful step is accustomed to, the person expects the beep, encouraging them to try harder. The researchers did not test whether the sensor changes dopamine levels in the brain, but they hope to stimulate a "dopamine-driven reward and feedback loop" that somehow compensates for the chemical depletion in the brains of people with Parkinson's.

The team says that with further research, the sensor could also be used by older people who do not have Parkinson's but have an unsteady gait that puts them at greater risk of falls and injury.

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Exciting New Antibiotic

Researchers have identified an entirely new class of antibiotics that can kill bacteria resistant to most existing drugs. This class of antibiotics, called zosurabalpine, was found to be highly effective against the bacteria Acinetobacter baumannii, a common cause of hospital infections and classified as a "priority 1" pathogen by the World Health Organization. This bacterium, which usually causes urinary tract, respiratory tract and bloodstream infections and potentially leads to sepsis, is responsible for about 20% of infections in hospitals, nursing homes and similar settings, and is unfortunately highly resistant to a powerful, broad-spectrum class of antibiotics called carbapenems. In a study published in the journal Nature in January, researchers from Harvard University and the pharmaceutical company Hoffmann-La Roche demonstrated that a new class of antibiotic, zosurabalpine, is effective against A. baumannii. Infections resistant to antibiotics, especially those caused by the Gram-negative bacteria group, pose a threat to human health.

Antibiotics generally show their effects by passing through the cell wall of bacteria and reaching the vital mechanism inside. Beta-lactams (penicillin, methicillin, cephalosporin) and non-beta-lactam antibiotics (vancomycin) attack the peptidoglycan cell wall of bacteria. 48 years after their initial discovery, carbapenems derived from penicillin work in the same way. Once inside the cell, antibiotics block this mechanism, stopping the growth of bacteria or causing cell death.

In this new study, scientists first identified a molecule that can pass through the cell wall and eliminate bacteria. The new class of antibiotics, zosurabalpine, has been shown to be highly effective against A. baumannii in both the laboratory and in infected animals. The researchers tested zosurabalpine against more than 100 A. baumannii samples from patients suffering from the infection. The team found that zosurabalpine was able to kill all of these bacteria. It was also able to kill bacteria in the bloodstream of infected mice, preventing them from developing sepsis. Zosurabalpine is currently being tested in phase 1 clinical trials to evaluate its safety in humans.