Thread-based potentiometric ion sensing

Researchers at Harvard have developed sensors for detection of ions, detection of sodium, potassium, chloride, and calcium are demonstrated, but the same design of device could be used to develop sensors for a wide range of ions. They use thread as substrate to fabricate the sensors. They show that multiplexed sensing of ions in sample volumes of 200 microliter can be accomplished by bundling the sensor together. The method for fabrication of the sensors is simple, low-cost, and scalable, and the sensors are portable and can be used at the point-of-use.

Commercial ion-sensing electrodes are big, bulky, delicate (with glass enclosures), and expensive and require large sample volumes. The technology uses ion-sensing electrodes using threads and heat shrinkable tubing (both low-cost materials) which perform similar to commercial electrodes, but can measure in much smaller sample volumes and are suitable for point-of-use or point-of-care. The thread-based ion-sensors are capable of multiplexed ion-sensing at the point-of-care and can be used as single-use devices or for multiple uses.

Most research for developing ion-sensors has been focused on using paper as a substrate, this work demonstrates the advantages of thread over paper, and shows that thread-based ion-sensing has more capabilities than paper-based ion sensing.

For physicians who are looking for an affordable device to measure levels of blood electrolytes at the point-of-care, the thread-based ion-selective electrodes enable this analysis and unlike clinical analyzers and handheld analyzers such as i-Stat, do not cost thousands of dollars. The thread-based ion-sensors allow multiplexed detection of blood electrolytes, and unlike, paper-based ion-sensors, a separate device for detection of each ion is not required. Unlike central labs which can take several hours up to days to report back the results, the thread-based ion-sensor provides the results in less than 10 minutes.

For quality control labs that use commercial ion-selective and reference electrodes for analysis of their samples, the thread-based ion-selective electrode delivers the same analysis, but requires orders of magnitude lower volumes of sample, and costs a fraction of the commercial electrodes.

For farmers who need to send samples of the soil of their land to soil testing laboratories, the thread-based ion-sensor can be used in the field to measure the concentration of ionic nutrient in the soil as a pre-screening tool, thus, eliminating the high expense of sending many samples of soil to the soil labs, and the wait time of weeks to months to get back the results.

Intellectual Property Status: Patent(s) Pending