Inkjet-printed device helps monitor a patient’s blood sugar levels without painful needles.
A technique that enables biologically active enzymes to survive the rigors of inkjet printing presents a promising alternative to routine blood screening exams faced by diabetic patients. The KAUST-led team used this approach to make disposable devices that can measure glucose concentrations in human saliva.
Strips of pH-sensitive paper are commonly used to test whether a liquid is acidic or alkaline. Researchers are now working to apply similar principles to create paper sensors that quickly indicate disease biomarkers. Key to this approach is replacing traditional electronic circuitry in the sensors with low-cost plastics that can be manufactured quickly and in large quantities.
Bioscientist Sahika Inal collaborated with electrical engineer Khaled Salama and materials scientist Derya Baran to use inkjet technology to produce sensors sensitive to small sugar concentrations in biofluids.
Utilizing a commercial ink made from conducting polymers, the team printed microscale electrode patterns onto glossy paper sheets. Next, they printed a sensing layer containing an enzyme, glucose oxidase, on top of the tiny electrodes. The biochemical reaction between available glucose and the enzyme creates electrical signals easily correlated to blood sugar levels.
“Paper is porous, which makes it challenging to print conducting and biological inks that are dissolved in water,” says Eloise Bihar, a postdoctoral researcher at KAUST and the first author of the study. “Printing the enzyme is tricky as well—it’s sensitive to variations of temperature, the voltage applied at the cartridge, and the pH of the ink.”
After optimizing the enzyme-printing conditions, the researchers had another obstacle to tackle. While fluids, such as sweat or saliva, contain enough sugar for monitoring purposes, they also contain molecules, such as ascorbic acid, that interfere electrically with conducting polymers. Coating the sensor with a nafion polymer membrane that repels the negative charges present in most interfering species enabled measurement of only the relevant glucose levels in saliva samples from volunteers.
Experiments showed the top coating gave the sensor an unprecedented shelf life—the enzyme could be kept alive and active for a month if stored in a sealed bag. These results are encouraging the team to expand the capabilities of this approach by incorporating different enzymes into the sensing layer.
“Optimization never ends in engineering, so we are trying to make this system more robust to detect other metabolites in biofluids,” says Inal. “We are also looking to integrate printed and self-powered energy devices into the sensors, giving us a more user-friendly platform that eliminates external batteries or wires.”
The Latest on: Paper sensors
via Google News
The Latest on: Paper sensors
- Hermetic LVDT displacement sensor for tough contaminated environmentson June 24, 2020 at 8:19 am
NewTek's HATR series of ac-operated LVDT displacement sensors are hermetically-sealed for use in tough contaminated environments such as pulp and paper mil ...
- Innovative 32-Bit Micros Target AI in IoT and Industry 4.0on June 24, 2020 at 7:35 am
Support for CMOS sensor interfaces and two simultaneous cameras is provided ... That standard is the OMA Lightweight Machine to Machine communications protocol—LwM2M—and a white paper 2 was published ...
- Researchers develop low-cost, easy-to-use emergency ventilator for COVID-19 patientson June 24, 2020 at 6:09 am
A team of engineers and physicians at the University of California San Diego has developed a low-cost, easy-to-use emergency ventilator for COVID-19 patients that is built around a ventilator bag ...
- Solid semiconductor sensor cooled with laseron June 24, 2020 at 5:54 am
The scientists described their technique in a Nature Communications paper. The team used a cantilever (a horizontal ... to thermal energy at room temperature and is sometimes used as a sensor. At the ...
- Exmor, Isocell & Co: why smartphone image sensors are so important!on June 23, 2020 at 11:06 am
This has - at least on paper - the advantage that more light is absorbed and more photons arrive at the sensor in the dark. Quantum efficiency diagrams show how sensitively different sensors react to ...
- Paper, Plastics, Rubber, Wood And Textile Marketon June 22, 2020 at 9:11 pm
Research Company offers Paper Plastics Rubber Wood And Textile Global Market Report 2020 30 Covid 19 Impact And Recovery in its research report store It is the most comprehensive report available on ...
- Paper chips pave the way to early forest fire alertson June 22, 2020 at 11:04 am
The detection and monitoring of forest fires currently relies on the use of satellite imagery, aerial patrols or ground crews. More timely feedback is crucial to combat fires before they spiral out of ...
- Why the pandemic unleashed a frenzy of toilet-paper buyingon June 19, 2020 at 4:18 am
Personality traits help to explain why some people and not others hoarded a humdrum product in the face of a deadly virus.
- Global Paper, Plastics, Rubber, Wood and Textile Markets, 2020-2030 - COVID-19 Impact and Recovery - ResearchAndMarkets.comon June 18, 2020 at 8:52 am
The "Paper, Plastics, Rubber, Wood And Textile Global Market Report 2020-30: COVID-19 Impact and Recovery" report has been added to ResearchAndMarkets.com's offering. The global paper, plastics, ...
- Self-powered 'paper chips' could help sound an early alarm for forest fireson June 17, 2020 at 9:35 am
Recent devastating fires in the Amazon rain forest and the Australian bush highlight the need to detect forest fires at early stages, before they blaze out of control. Current methods include infrared ...
via Bing News