Flexible, Thin-Film Biosensors

We like to keep a pulse on the latest biosensor research going on around the world. One class of biosensors that have really caught our attention is the so-called thin-film sensors, pioneered by the Rogers Research Group at Northwestern University.

We’re no strangers to the flexible PCB here at Hackaday. Flexible PCBs have become increasingly accessible to small-scale developers and hobbyists, explaining why we’re seeing them incorporated into many academic research projects. The benefit of these types of sensors lies in the similarity of their mechanical properties to those of human skin. Human skin is flexible, so matching the flexibility of skin allows these thin-film sensors to adhere more comfortably and naturally to a person’s body. Continue reading “Flexible, Thin-Film Biosensors”

Picture of NanoStat in 3D-printed enclosure with LiPo battery and US quarter for scale.

An ESP32-Based Potentiostat

Ever wanted to make your own wireless chemical sensor? Researchers from the University of California, Irvine (UC Irvine) have got you covered with their ESP32-based potentiostat.

We’ve talked about potentiostats here on Hackaday before. Potentiostats are instruments that analyze the electrical properties of an electroactive chemical cell. Think oxidation and reduction reactions (redox) from your chemistry course, if you can remember that far back. Potentiostats can be used in several different modes/configurations, but the general idea is for these instruments to induce redox reactions within a given electroactive chemical cell and then measure the resulting current produced by the reaction. By measuring the current, researchers can determine the concentration of a known substance within a sample or even determine the identity of an unknown substance, to name a few potential applications.

These instruments have become mainstays in research labs around the world and have incredible utility in the consumer space. Glucometers, devices used to measure blood glucose levels, are an example of technologies that have made their way into everyday life due to the advances made in electrochemistry and potentiostat research over the last few decades. Given their incredible utility to scientific research and medical technologies, a great deal of effort has gone into democratizing potentiostats, making them more available to the general public for educational and hobbyist purposes. Of course, any medical applications must go through rigorous testing and approvals by each country’s appropriate governing bodies. So we’re talking more non-medical purposes here.

The first popular open-source, DIY potentiostat was the CheapStat, which we’ve covered here on Hackaday before. Since then, developing newer and more advanced open-source potentiostats has become a popular endeavor within the scientific community. The researchers from UC Irvine wanted to put their own special spin on the open-source potentiostat craze and they did so with their inclusion of the ESP32 as their main processor. This obviously opens up them up do a whole host (see what we did there) of wireless capabilities that others before them have not explored.

With the ESP32, they developed a nice web-based GUI that makes controlling and collecting data from the potentiostat very seamless and user-friendly. You can imagine the great possibilities here. Teacher-led classroom demonstrations where the instructor can easily access each student’s device over the cloud to help troubleshoot or explain results. Developing soil monitoring sensors that can be deployed all around a farm to remotely collect data on feed, soil composition, and plant health. The possibilities here sure are promising.

We hope you’ll dive into their paper as it’s well worth a read. Happy hacking, Hackaday.

Coronavirus Testing: CRISPR Technology Set To Streamline Viral Testing

If we could run back 2020 to its beginning and get a do-over, chances are pretty good that we’d do a lot of things differently. There’s a ton of blame to go around on COVID-19, but it’s safe to say that one of the biggest failures of this whole episode has been the lack of cheap, quick, accurate testing for SARS-CoV-2, the virus behind the current pandemic. It’s not for lack of information; after all, Chinese scientists published the sequence of the viral genome very early in the pandemic, and researchers the world over did the same for all the information they gleaned from the virus as it rampaged around the planet.

But leveraging that information into usable diagnostics has been anything but a smooth process. Initially, the only method of detecting the virus was with reverse transcriptase-polymerase chain reaction (RT-PCR) tests, a fussy process that requires trained technicians and a well-equipped lab, takes days to weeks to return results, and can only tell if the patient has a current infection. Antibody testing has the potential for a quick and easy, no-lab-required test, but can only be used to see if a patient has had an infection at some time in the past.

What’s needed as the COVID-19 crisis continues is a test with the specificity and sensitivity of PCR combined with the rapidity and simplicity of an antibody test. That’s where a new assay, based on the latest in molecular biology methods and dubbed “STOPCovid” comes in, and it could play a major role in diagnostics now and in the future.

Continue reading “Coronavirus Testing: CRISPR Technology Set To Streamline Viral Testing”

A Smart Bandage For Monitoring Chronic Wounds

Here at Hackaday, we’re always enthralled by cool biohacks and sensor development that enable us to better study and analyze the human body. We often find ourselves perusing Google Scholar and PubMed to find the coolest projects even if it means going back in time a year or two. It was one of those scholarly excursions that brought us to this nifty smart bandage for monitoring wound healing by the engineers of FlexiLab at Purdue University. The device uses an omniphobic (hydrophobic and oleophobic) paper-based substrate coupled with an onboard impedance analyzer (AD5933), an electrochemical sensor (the same type of sensor in glucometers) for measuring uric acid and pH (LMP91000), and a 2.4 GHz antenna for wirelessly transmitting the data (nRF24L01). All this is programmed with an Arduino Nano. They even released their source code.

To detect uric acid, they used the enzyme uricase, which is very specific to uric acid and exhibits low cross-reactivity with other compounds. They drop cast uric acid onto a silver/silver chloride electrode printed on the omniphobic paper. Similarly, to detect pH, they drop cast a pH-responsive polymer called polyaniline emeraldine salt (PANI-ES) between two separate silver/silver chloride electrodes. All that was left was to attach the electrodes to the LMP91000, do a bit of programming, and there they were with their own electrochemical sensor. The impedance analyzer was a bit simpler to develop, simply attaching un-modified electrodes to the AD5933 and placing the electrodes on the wound.

The authors noted that the device uses a much simpler manufacturing process compared to smart bandages published by other academics, being compatible with large-scale manufacturing techniques such as roll-to-roll printing. Overcoming manufacturing hurdles is a critical step in getting your idea into the hands of consumers. Though they have a long way to go, FlexiLab appears to be on the right track. We’ll check back in every so often to see what they’re up to.

Until then, take a look at some other electric bandage projects on Hackaday or even make your own electrochemical sensor.

Treating Vertigo But Not The Catchy Pop Song

Benign Paroxysmal Positional Vertigo (BPPV), or simply vertigo, is a condition that creates a sensation of dizziness and spinning, leading to nausea and loss of balance. These symptoms occur due to the dislodging of calcium carbonate crystals in the ear (imagine always feeling dizzy and having salt in your ears, not great). This disease is especially prominent in persons over 65, which is even more problematic considering such populations are especially susceptible to falling and dying from complications from the fall.

To treat vertigo, specialized physicians called vestibular specialists to guide patients through a series of head motions collectively referred to as the Epley maneuver. However, many patients must travel for hours to see a specialist since non-BPPV specialists often feel uncomfortable performing the maneuver.

As a result, Purdue Medical Innovation, Networking, and Design (MIND) developed, Verti-Fix, a solution that will guide non-BPPV specialists through the Epley maneuver using accelerometers and gyroscopes and could also be used by patients at-home as well. By doing so, Verti-Fix is able to provide feedback on how fast or how slowly patients are progressing through the maneuver. Purdue MIND coupled their device with indicator lights to alert physicians if they have performed a specific motion incorrectly and provide detailed feedback on steps performed and steps remaining on an LCD screen. The device is even powered by one of our personal favorite microcontrollers, the ATmega328P. Purdue MIND have detailed their design with schematics and code on Hackster.io giving the community an opportunity to remix, reuse, and reshare.

Purdue MIND are already upgrading their prototype to include eye-tracking and wireless capabilities. Additionally, they recently competed in the Rice 360o┬áDesign Competition and placed among the Top 20 teams! We’ll be watching to see how they advance their prototype further.

In the meantime, check out out some other at-home monitoring projects on Hackaday.