Close-up of a magnetic tentacle robot next to a phantom bronchiole (Credit: University of Leeds)

The Healing Touch Of Magnetic Tentacles In Photothermal Lung Cancer Therapy

August 28, 2023 by Maya Posch 11 Comments

Of the body’s organs, the lungs are among the trickiest to take a biopsy and treat cancer in, both due to how important they are, as well as due to their inaccessibility. The total respiratory surface within the average human lungs is about 50 to 75 square meters. Maneuvering any kind of instrument down the endless passages to reach a suspicious area, or a cancerous region to treat is nearly impossible. This has so far left much of the lungs inaccessible.

The standard of care for lung cancer is generally surgical: remove parts of the lung tissue. However, a proposed new method using magnetic tentacles may soon provide a more gentle approach, as described in Nature Engineering Communications by Giovanni Pittiglio and colleagues (press release).

The tentacles are made out of a silicone substrate with embedded magnets that allow for it to be steered using external magnetic sources. With an embedded laser fiber, the head of the tentacle can be guided to the target area, and the cancerous tissue sublimated using an external laser source. In experiments on cadavers with this system, the researchers found that they could enter 37% deeper into the lungs than with standard equipment. The procedure was also completed with less tissue displacement.

Considering the high fatality rate of lung cancers, the researchers hope that this approach could soon be turned into a viable therapy, as well as for other medical conditions where a gentle tentacle slithering into the patient’s body could effect treatments previously considered to be impossible.

Heading image: Close-up of a magnetic tentacle robot next to a phantom bronchiole (Credit: University of Leeds)

A credit card-sized PCB with two sensing pads and a small OLED display

Card/IO Is A Credit Card-Sized, Open Source ECG Monitor

August 27, 2023 by Robin Kearey 23 Comments

Of all the electrical signals generated by the human body, those coming from the heart are probably the most familiar to the average person. And because it’s also quite simple to implement the required sensors, it makes sense that electrocardiogram (ECG) machines are a popular choice among introductory medical electronics projects. [Dániel Buga], for instance, designed a compact ECG system the size of a credit card, cleverly dubbed Card/IO, that clearly demonstrates how to implement a single-lead ECG.

Although obviously not a medical-grade instrument, it still contains all the basic components that make up a proper biosignal sensing system. First, there are the sensing pads, which sense the voltage difference between the user’s two thumbs and simultaneously cancel their common-mode voltage with a technique called Right Leg Driving (RLD). The differential signal then goes through a low-pass filter to remove high-frequency noise, after which it enters an ADS1291 ECG analog front-end chip.

The ADS1291 contains a delta-sigma analog-to-digital converter as well as an SPI bus to communicate with the main processor. [Dániel] chose an ESP32-S3, programmed in Rust, to interface with the SPI bus and drive a 1″ OLED display that shows the digitized ECG signal. It also runs the user interface, which is operated using the ECG sensing pads: if you touch them for less than five seconds, the device goes into menu mode and the two pads become buttons to scroll through the different options.

All source code, as well as KiCad files for the board, can be found on the project’s GitHub page. If you’re just getting started in the biosensing field, you might also want check out this slightly more advanced project that includes lots of relevant safety information.

Continue reading “Card/IO Is A Credit Card-Sized, Open Source ECG Monitor” →

Showing pulse oximeter and color sensor combining to measure oxygen in blood and skin tone

Perfecting The Pulse Oximeter

August 7, 2023 by Orlando Hoilett 28 Comments

We’re always looking for interesting biohacks here on Hackaday, and this new research article describing a calibrated pulse oximeter for different skin tones really caught our attention.

Pulse oximeters are handy little instruments that measure your blood oxygen saturation using photoplethysmography (PPG) and are a topic we’re no strangers to here at Hackaday. Given PPG is an optical technique, it stands to reason that its accuracy could be significantly affected by skin tone and that has been a major topic of discussion recently in the medical field. Given the noted issues with pulse oximeter accuracy, these researchers endeavored to create a better pulse oximeter by quantifying skin pigmentation and using that data to offset errors in the pulse oximeter measurements. A slick idea, but we think their results leave a lot to be desired.

Their idea sounds pretty straightforward enough. They created their own hardware to measure blood oxygen saturation, a smartwatch that includes red and infrared (IR) light-emitting diodes (LED) to illuminate the tissue just below the surface of the skin, and a photosensor for measuring the amount of light that reflects off the skin. But in addition to the standard pulse oximeter hardware, they also include a TCS34725 color sensor to quantify the user’s skin tone.

So what’s the issue? Well, the researchers mentioned calibrating their color sensor to a standard commercially-available dermatology instrument just to make sure their skin pigmentation values match a gold standard, but we can’t find that data, making it a bit hard to evaluate how accurate their color sensor actually is. That’s pretty crucial to their entire premise. And ultimately, their corrected blood oxygen values don’t really seem terribly promising either. For one individual, they reduced their error from 5.44% to 0.82% which seems great! But for another user, their error actually increases from 0.99% to 6.41%. Not so great. Is the problem in their color sensor calibration? Could be.

We know from personal experience that pulse oximeters are hard, so we applaud their efforts in tackling a major problem. Maybe the Hackaday community could help them out?

Fiber-Infused Ink Allows 3D-Printed Heart Muscle To Beat

July 29, 2023 by Maya Posch 7 Comments

Illustration from Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013.

What makes a body’s organs into what they are is more than just a grouping of specialized cells. They also need to be oriented and attached to each other and scaffolding in order to create structures which can effectively perform the desired function. A good example here is the heart, which requires a large number of muscle cells to contract in unison in order for the heart component (like a ventricle) to effectively pump blood. This complication is what has so far complicated efforts to 3D print complex tissues and entire organs, but recently researchers have demonstrated a way to 3D print heart muscle which can contract when stimulated similarly to a human heart’s ventricle.

At the center of this technique lies a hydrogel that is infused with gelatin fibers. Using a previously developed Rotary Jet-Spinning technology that was reported on in 2016, a sheet of spun fibers was produced that were then cut up into micrometer-sized fibers which were dispersed into the hydrogel. After printing the desired structure – taking into account the fiber alignment – it was found that the cardiomyocytes (the cells responsible for carrying the contractile signal in the heart muscle) align along the thus laid out pattern, ultimately creating a cardiac muscle capable of organized contraction.

These findings come after many years of research into the topic, with e.g. Zihan Wang and colleagues in a 2021 paper reporting on the challenges remaining with 3D printing cardiac tissue, yet also the massive opportunities that this could provide. Although entire heart replacements (via therapeutic cloning with the patient’s own cells) might become possible too, more immediate applications would involve replacements for damaged cardiac muscle and other large structures of the heart.

Open-Source LAMP Instrument Aimed At Clinicians And Biohackers Alike

July 14, 2023 by Dan Maloney 28 Comments

Over the last few years, we’ve all been given a valuable lesson in both the promise and limitations of advanced molecular biology methods for clinical diagnostics. Polymerase chain reaction (PCR) was held up as the “gold standard” of COVID-19 testing, but the cost, complexity, and need for advanced instrumentation and operators with specialized training made PCR difficult to scale to the levels demanded by a pandemic.

There are other diagnostic methods, of course, some of which don’t have all the baggage of PCR. RT-LAMP, or reverse transcriptase loop-mediated amplification, is one method with a lot of promise, especially when it can be done on a cheap open-source instrument like qLAMP. For about 50€, qLAMP makes amplification and detection of nucleic acids, like the RNA genome of the SARS-CoV-2 virus, a benchtop operation that can be performed by anyone. LAMP is an isothermal process; it can be done at one single temperature, meaning that no bulky thermal cycler is required. Detection is via the fluorescent dye SYTO 9, which layers into the base pairs inside the amplified DNA strands, using a 470-nm LED for excitation and a photodiode with a filter to detect the emission. Heating is provided by a PCB heater and a 3D-printed aluminum block that holds tubes for eight separate reactions. Everything lives in a 3D-printed case, including the ESP32 which takes care of all the housekeeping and data analysis duties.

With the proper test kits, which cost just a couple of bucks each, qLAMP would be useful for diagnosing a wide range of diseases, and under less-than-ideal conditions. It could also be a boon to biohackers, who could use it for their own citizen science efforts. We saw a LAMP setup at the height of the pandemic that used the Mark 1 eyeball as a detector; this one is far more quantitative.

MIT Engineers Pioneer Cost-Effective Protein Purification For Cheaper Drugs

June 26, 2023 by Lewin Day 10 Comments

There are a wide variety of protein-based drugs that are used to treat various serious conditions. Insulin is perhaps the most well-known example, which is used for life-saving treatments for diabetes. New antibody treatments also fall into this category, as do various vaccines.

A significant cost element in the production of these treatments is the purification step, wherein the desired protein is separated from the contents of the bioreactor it was produced in. A new nanotech discovery from MIT could revolutionize this area, making these drugs cheaper and easier to produce.

Continue reading “MIT Engineers Pioneer Cost-Effective Protein Purification For Cheaper Drugs” →

A glass plate holds a translucent set of silver electrodes. The plate appears to be suspended across two petri dishes, so the scale must be small.

Hydrogels For Bioelectronic Interfaces

June 25, 2023 by Navarre Bartz 1 Comment

Interfacing biological and electrical systems has traditionally been done with metal electrodes, but something flexible can be more biocompatible. One possible option is 3D-printed bioelectric hydrogels.

Electrically conductive hydrogels based on conducting polymers have mechanical, electrical, and chemical stability properties in a fully organic package that makes them more biocompatible than other systems using metals, ionic salts, or carbon nanomaterials. Researchers have now found a way to formulate bi-continuous conducting polymer hydrogels (BC-CPH) that are a phase-separated system that can be used in a variety of manufacturing techniques including 3D printing.

To make the BC-CPH, a PEDOT:PSS electrical phase and a hydrophilic polyurethane mechanical phase are mixed with an ethanol/water solvent. Since the phase separation occurs in the ink before deposition, when the solvent is evaporated, the two phases remain continuous and interspersed, allowing for high mechanical stability and high electrical conductivity which had previously been properties at odds with each other. This opens up new avenues for printed all-hydrogel bioelectronic interfaces that are more robust and biocompatible than what is currently available.

If you want to try another kind of squishy electrode gel, try growing it.