📋 Tender Overview
Someday doctors would like to grow limbs and other body tissue for soldiers who have lost arms in battle children who need a new heart or liver and many other people with critical needs. Today medical professionals can graft cells from a patient deposit them onto a tissue scaffold and insert the scaffold into the body to encourage the growth of bone cartilage and other specialized tissue. But researchers are still working toward building complex organs that can be implanted into patients.Scientists at the National Institute of Standards and Technology NIST are supporting this field of research by developing a promising new kind of light-based sensor to study tissue growth in the lab.The NIST teams proof-of-concept work published today in Sensors and Actuators B demonstrates a small sensor that uses a light-based signal to measure pH the measurement unit for acidity an important property in cell-growth studies. The same basic design could be used to measure other qualities such as the presence of calcium cell growth factor and certain antibodies.Unlike conventional sensors this measurement method could be used to monitor the environment in a cell culture long-term for weeks at a time without having to disturb the cells regularly to calibrate the sensing instruments. Watching properties of the tissue in real time as they slowly change over days or weeks could greatly benefit tissue engineering studies to grow teeth heart tissue bone tissue and more said NIST chemist Zeeshan Ahmed.We want to make sensors that can be put inside growing tissue to give researchers quantitative information Ahmed said. Is the tissue actually growing Is it healthy If you grow a bone does it have the right mechanical properties or is it too weak to support a bodyThe work could have benefits beyond tissue engineering too into studying the progression of diseases such as cancer.What these sensors could give people is real-time information about tissue growth and disease progression said American University chemist and NIST guest researcher Matthew Hartings. Conventional sensors give researchers a series of snapshots without showing them the path between those points Hartings said. But photonic sensors could provide scientists with continuous information the equivalent of a GPS navigation app for disease.We want to provide researchers with a detailed map of the incremental changes that happen as tissue either grows in a healthy way or becomes diseased Hartings said. Once researchers know the streets a disease is taking then they can better prevent or support the changes that are happening in a patients body.A Problem to SolveMeasurements of pH are a vital part of tissue engineering studies. As cells grow their environment naturally becomes more acidic. If the environment becomes too acidic or too basic the cells will die. Scientists measure pH on a scale from 0 very acidic to 14 very basic with an ideal environment for most cells in a narrow range around a pH of 7.Commercial pH instruments are highly accurate but unstable meaning they require frequent calibrations to ensure accurate readings day to day. Without calibration these conventional pH meters lose up to 0.1 pH units of accuracy daily. But tissue engineering studies take place on the order of weeks. A culture of stem cells might need to be grown for almost a month before they turn into bone.An increment of 0.1 pH is significant Ahmed said. If your pH value changes by 1 you kill the cells. If after a few days I cant trust anything about my pH measurement then Im not going to use that measurement method.On the other hand if researchers disturb the growing cells every time they have to measure the cell cultures pH then the scientists are introducing another kind of uncertainty to their measurements since they are altering the cells environment.Whats needed for this kind of research Ahmed said is a measurement system that can stay inside an incubator with the cells in their culture medium and not need to be removed or calibrated for weeks at a time.
