Research could lead to new biomarkers for clinical laboratory tests that spot disease early in patients
As we have covered in previous Dark Daily ebriefs, there are ongoing efforts to develop diagnostic assays that use human breath as the specimen. One early example was the breath specimen for Helicobacter pylori (H. pylori) testing—the bacteria that causes peptic ulcers—in the 1990s. Thus, a new sensor developed by scientists at Zhejiang University in China that can detect the presence of lung cancer in human breath will be of interest to medical laboratory scientists and clinical laboratories working on such testing.
In a proof-of-concept study, the Zhejiang University researchers “developed ultrasensitive nanoscale sensors that in small-scale tests distinguished a key change in the chemistry of the breath of people with lung cancer,” according to an American Chemical Society (ACS) news release.
The new research exemplifies how instruments are becoming increasingly sensitive to detection of smaller specimen quantities, making it possible to even use exhaled breath to diagnose lung cancer, noted a review article published in Science Direct.
“This study presents a novel Pt@InNiOx [platinum (Pt), indium (In), nickel (Ni)] nanoflake isoprene sensor that achieves an exceptionally low limit of detection at two parts per billion (2ppb)—the lowest reported for isoprene sensor to date,” wrote study lead author, Pingwei Liu, PhD (above), distinguished research fellow, Zhejiang University, et al, in ACS Sensors. “Our work not only provides a breakthrough in low-cost, noninvasive cancer screening through breath analysis but also advances the rational design of cutting-edge gas sensing materials.” Clinical laboratories working with breath sample biomarkers will be intrigued by this new advancement in the technology. (Photo copyright: Zhejiang University.)
Finding the Breakthrough Sensor
The Zhejiang University researchers were motivated by the potential for rapid gas sensing in diagnostics. Many gases, including carbon dioxide, are exhaled. But one particular gas, isoprene, they found “can indicate the presence of lung cancer,” the news release states.
However, while breath is readily available, it is not easy to isolate breath biomarkers. That is because a detector needs to “differentiate between volatile chemicals, withstand the natural humidity of exhaled breath, and detect tiny quantities of specific chemicals,” New Atlas explained.
To detect small specimen quantities of isoprene, a highly sensitive sensor needed to be developed—one that would be a step up from standard indium oxide-based breath sensors.
The scientists experimented with a series of indium (III) oxide (In203)-based nanoflake sensors until they found the sensor that performed consistently in nine experiments. They called it Pt@InNiOx for the platinum (Pt), indium (In), and nickel (Ni) it contained.
According to the news release, the Pt@InNiOx sensor:
Had “sensitivity that far surpassed earlier sensors” as evidenced by detection of isoprene as low as 2ppb.
Emphasized isoprene attraction over other volatile compounds in breath.
Has advanced sensitivity due to “Pt nanoclusters uniformly anchored on the nanoflakes” activating the isoprene sensing.
Gadget Review described the innovation as a “significant advance in diagnostic capability” that uses nanoscale technology along with “indium oxide nanoflakes with platinum-based nanoclusters.”
Developing the Lung Cancer Diagnostic Device
The scientists put their Pt@InNiOx nanoflakes into a portable sensing device for breath analysis. They then inserted breath samples from 13 people including five who had lung cancer. They found that:
In samples from people with cancer, the device enabled detection of isoprene levels lower than 40 ppb.
In samples from cancer-free participants, the device found isoprene levels more than 60 ppb.
“We integrate these ultrasensitive Pt@InNiOx nanoflakes into a miniaturized portable electronic device that successfully distinguishes lung cancer patients with expiratory isoprene below 40ppb, from the healthy population with isoprene above 60 ppb, enabling an accurate diagnosis in clinics,” wrote study lead author, Pingwei Liu, PhD, distinguished research fellow, Zhejiang University, et al, in ACS Sensors.
“As the isoprene hits the nanoflakes, electron release is sparked in a way that can be measured,” MSN Health reported, adding that the nanoflakes were also able to find isoprene in other chemicals and operate even in humid conditions.
Breath as Lab Test Biomarker for Cancer
In the United States, more people die from lung cancer than any other form of cancer, according to US Centers for Disease Control and Prevention statistics. The CDC data show there were 209,500 new lung and bronchus cancer cases in 2022, the most recent year for available data.
The Zhejiang University scientists reportedly plan to continue their research on the sensing materials and link between isoprene and lung cancer.
Studies continue to show many components in human breath can be used as clinical laboratory test biomarkers. Assays that use the breath as specimen may one day play an important role in early diagnosis of lung cancer and other diseases.
Clinical laboratories and point-of-care settings may have a new diagnostic test if this novel handheld device and related technology is validated by clinical trials
Efforts to develop breath analyzers that accurately identify viral infections, such as SARS-CoV-2 and Influenza, have been ongoing for years. The latest example is ViraWarn from Opteev Technologies in Baltimore, Maryland, and its success could lead to more follow-up PCR tests performed at clinical laboratories.
“Breath is one of the most appealing non-invasive sample types for diagnosis of infectious and non-infectious disease,” said Opteev in its FDA Pre-EUA application. “Exhaled breath is very easy to provide and is less prone to user errors. Breath contains a number of biomarkers associated with different ailments that include volatile organic compounds (VOCs), viruses, bacteria, antigens, and nucleic acid.”
Further clinical trials and the FDA Pre-EUA are needed before ViraWarn can be made available to consumers. In the meantime, Opteev announced that the CES (Consumer Electronic Show) had named ViraWarn as a 2023 Innovation Award Honoree in the digital health category.
“ViraWarn is designed to allow users an ultra-fast and convenient way to know if they are spreading a dangerous respiratory virus. With a continued increase in COVID-19 and a new surge in RSV and influenza cases, we’re eager to bring ViraWarn to market so consumers can easily blow into a personal device and find out if they are positive or negative,” said Conrad Bessemer (above), Opteev President and Co-Founder, in a news release.
Opteev is a subsidiary of Novatec, a supplier of machinery and sensor technology, and a sister company to Prophecy Sensorlytics, a wearable sensors company.
The ViraWarn breath analyzer uses a silk-based sensor that “traces the electric discharge of respiratory viruses coupled with an artificial intelligence (AI) processor to filter out any potential inaccuracies,” according to the news release.
Here is how the breath analyzer (mouthpiece, attached biosensor chamber, and attached printed circuit board chamber) is deployed by a user, according to the Opteev website:
The user turns on the device and an LED light indicates readiness.
The user blows twice into the mouthpiece.
A carbon filter stops bacteria and VOCs and allows virus particles to pass through.
As “charge carriers,” virus particles have a “cumulative charge.”
Electrical data are forwarded to the AI processor.
The AI processer delivers a result.
Within 60 seconds, a red signal indicates a positive presence of a virus and a green signal indicates negative one.
“The interaction of the virus with a specially designed liquid semiconductive medium, or a solid polymer semiconductor, generates changes in the conductivity of the electrical biosensor, which can then be picked up by electrodes. Such electrical data can be analyzed using algorithms and make a positive or negative call,” explains an Opteev white paper on the viral screening process.
While the ViraWarn breath analyzer can identify the presence of a virus, it cannot distinguish between specific viruses, the company noted. Therefore, a clinical laboratory PCR test is needed to confirm results.
Other Breath Tests
Opteev is not the only company developing diagnostic tests using breath samples.
For clinical laboratory managers and pathologists, Opteev’s ViraWarn is notable in breath diagnostics development because it is a personal hand-held tool. It empowers people to do self-tests and other disease screenings, all of which would need to be confirmed with medical laboratory testing in the case of positive results.
Further, it is important to understand that consumers are the primary target for this novel diagnostic device. This is consistent with investor-funding companies wanting to develop testing solutions that can be used by consumers. At the same time, a device like ViraWarn could be used by clinical laboratories in their patient service centers to provide rapid test results.
Should the device prove effective, it could replace invasive point-of-care blood draws for clinical laboratory testing during patient drug therapy monitoring
What if it were possible to perform therapeutic drug monitoring (TDM) without invasive blood draws using breath alone? Patients fighting infections in hospitals certainly would benefit. Traditional TDM can be a painful process for patients, one that also brings risk of bloodline infections. Nevertheless, regular blood draws have been the only reliable method for obtaining viable samples for testing.
One area of critical TDM is in antibiotic therapy, also known as personalized antibiotherapy. However, for antibiotic therapy to be successful it typically requires close monitoring using point-of-care clinical laboratory testing.
Now, a team of engineers and biotechnologists from the University of Freiburg in Germany have developed a biosensor that can use breath samples to measure antibiotic concentrations present in blood, according to a University of Freiburg press release.
The team’s non-invasive collection method requires no needle sticks and can allow for frequent specimen collections to closely monitor the levels of an antibiotic prescribed for a patient. The biosensor also provides physicians the ability to tailor antibiotic regimens specific to individual patients, a core element of precision medicine.
“Until now researchers could only detect traces of antibiotics in the breath,” said Can Dincer, PhD (above), Junior Research Group Leader at the University of Freiburg, and one of the authors of the study, in the press release. “With our synthetic proteins on a microfluid chip, we can determine the smallest concentrations in the breath condensate and [how] they correlate with the blood values.” Should the breath biosensor prove effective in clinical settings, painful blood draws for clinical laboratory testing at the point of care could become obsolete. (Photo copyright: Conny Ehm/University of Freiburg.)
Can a Breath Biosensor Be as Accurate as Clinical Laboratory Testing?
The University of Freiburg’s biosensor is a multiplex, microfluid lab-on-a-chip based on synthetic proteins that react to antibiotics. It allows the simultaneous measurement of several breath samples and test substances to determine the levels of therapeutic antibiotics in the blood stream.
To perform their research, the University of Freiburg team tested their biosensor on blood, plasma, urine, saliva, and breath samples of pigs that had been given antibiotics. The results the researchers achieved with their device using breath samples were as accurate as standard clinical laboratory testing, according to the press release.
The microfluidic chip contains synthetic proteins affixed to a polymer film via dry film photoresist (DFR) technology. These proteins are similar to proteins used by drug-resistant bacteria to sense the presence of antibiotics in their environment. Each biosensor contains an immobilization area and an electrochemical cell which are separated by a hydrophobic stopping barrier. The antibiotic in a breath sample binds to the synthetic proteins which generates a change in an electrical current.
“You could say we are beating the bacteria at their own game,” said Wilfried Weber, PhD, Professor of Biology at the University of Freiburg and one of the authors of the research paper, in the press release.
Rapid Monitoring at Point-of-Care Using Breath Alone
The biosensor could prove to be a useful tool in keeping antibiotic levels stable in severely ill patients who are dealing with serious infections and facing the risk of sepsis, organ failure, or even death. Frequent monitoring of therapeutic antibiotics also could prevent bacteria from mutating and causing the body to become resistant to the medications.
“Rapid monitoring of antibiotic levels would be a huge advantage in hospital,” said H. Ceren Ates, PhD, scientific researcher at the University of Freiburg and one of the authors of the study in the press release. “It might be possible to fit the method into a conventional face mask.”
Along those lines, the researchers are also working on a project to create wearable paper sensors for the continuous measurement of biomarkers of diseases from exhaled breath. Although still in the development stages, this lightweight, small, inexpensive paper sensor can fit into conventional respiratory masks, according to a University of Freiburg press release.
Other Breath Analysis Devices Under Development
Devices that sample breath to detect biomarkers are not new. Dark Daily has regularly reported on similar developments worldwide.
Thus, University of Freiburg’s non-invasive lab-on-a-chip biosensor is worth watching. More research is needed to validate the effectiveness of the biosensor before it could be employed in hospital settings, however, monitoring and managing antibiotic levels in the body via breath samples could prove to be an effective, non-invasive method of providing personalized antibiotic therapy to patients.
Clinical trials on human breath samples are being planned by the University of Freiburg team. This type of precision medicine service may give medical professionals the ability to maintain proper medication levels within an optimal therapeutic window.
Device could pave the way for real-time, noninvasive breath analysis to detect and monitor diseases and be a new service medical laboratories can offer
Breathalyzer technology is not new, but until now human breath detection devices have not been comparable to clinical laboratory blood testing for disease detection and monitoring. That may soon change and there are implications for clinical laboratories, partly because breath samples are considered to be non-invasive for patients.
Scientists with JILA, a research center jointly operated by the National Institutes of Standards and Technology (NIST) and the University of Colorado Boulder, recently increased the sensitivity of their laser frequency comb breathalyzer one thousand-fold. This created a device that can detect four disease biomarkers simultaneously, with the potential to identify six more, according to an NIST news release.
Medical laboratory scientists will understand the significance of this development. JILA’s enhanced breathalyzer device could pave the way for real-time, noninvasive breath analysis to detect and monitor diseases, and potentially eliminate the need for many blood-based clinical laboratory tests.
During their research, physicist Jun Ye, PhD, and David Nesbitt, PhD, both Fellows at JILA and professors at University of Colorado Boulder, detected and monitored four biomarkers in the breath of a volunteer:
These chemicals can be indicators of various health conditions. Methane in the breath, for example, can indicate intestinal problems.
The researchers say the JILA breathalyzer also could detect six additional biomarkers of disease without any further modifications to the device. They would include:
NIST/JILA Research Fellows Jun Ye, PhD (left), and David Nesbitt, PhD (right) of the University of Colorado Boulder, “built a breathalyzer that identifies biomarkers of disease by measuring the colors and amounts of light absorbed as a laser frequency comb passes through breath samples inside a glass tube,” according to an NIST news release. Should they succeed in creating a portable version, their noninvasive device could become an option compared to conventional clinical laboratory blood testing methods used to identify and monitor diseases. (Photos copyright: University of Colorado Boulder.)
“Determining the identity and concentration of the molecules present in breath is a powerful tool to assess the overall health of a person, analogous to blood testing in clinical medicine, but in a faster and less invasive manner,” the researchers wrote in PNAS.
“The presence of a particular molecule (or combination of molecules) can indicate the presence of a certain health condition or infection, facilitating a diagnosis. Monitoring the concentration of the molecules of interest over time can help track the development (or recurrence) of a condition, as well as the effectiveness of the administered treatment,” they added.
How the JILA Breathalyzer Detects Biomarkers
According to a 2008 NIST news release, JILA researchers had developed a prototype comb breathalyzer in that year. However, the research did not continue. But then the COVID-19 pandemic brought the JILA/NIST laboratories focus back to the breathalyzer with hopes that new research could lead to a breath test for detecting the SARS-CoV-2 coronavirus and other conditions.
“We are really quite optimistic and committed to pushing this technology to real medical applications,” Ye said in the 2021 NIST news release.
Analytical Scientist explained that JILA’s new and improved breathalyzer system “fingerprints” chemicals by measuring the amount of light absorbed as a laser frequency comb passes back and forth through breath samples loaded into a mirrored glass tube.
JILA’s original 13-year-old prototype comb analyzed colors and amounts of light in the near-infrared band. However, JILA’s recent improvements include advances in optical coatings and a shift to analyzing mid-infrared band light, allowing detection sensitivity up to parts-per-trillion level, a thousand-fold improvement over the prototype.
Corresponding study author Jutta Toscano, PhD, postdoctoral researcher at the University of Basel in Switzerland and previously Lindemann fellow at JILA, told Physics World the new frequency comb can “probe the molecular fingerprint region where fundamental, and more intense, spectroscopic transitions are found.
“By matching the frequency of the comb teeth with the cavity modes—the ‘standing modes’ of the cavity—we can increase the interaction path length between molecules inside the cavity and laser light by a factor of around 4000, equivalent to an effective path length of a few kilometers,” she added. “We then probe the light that leaks out of the cavity by sending it into an FTIR [Fourier-transform infrared] spectrometer to find out which exact comb teeth have been absorbed and by how much. In turn, this tells us which molecules are present in the breath sample and their concentration.”
Even Hippocrates Studied Breath
Ye noted in the NIST statement that JILA is the only institution that has published research on comb breathalyzers.
In their PNAS paper, the researchers wrote, “Breath analysis is an exceptionally promising and rapidly developing field of research, which examines the molecular composition of exhaled breath. … Despite its distinctive advantages of being a rapid, noninvasive technique and its long history dating back to Hippocrates, breath analysis has not yet been as widely deployed for routine diagnostics and monitoring as other methods, such as blood-based analysis.
“We have shown that this technique offers unique advantages and opportunities for the detection of light biomarkers in breath,” the researchers noted, “and it is poised to facilitate real-time, noninvasive monitoring of breath for clinical studies, as well as for early detection and long-term monitoring of temporary and permanent health conditions.”
Validation of these findings and further design research to make the system portable are required before JILA’s frequency comb breathalyzer can become a competitor to clinical laboratory blood tests for disease identification and monitoring. Nevertheless, JILA’s research brings breathalyzer technology a step closer to offering real-time, non-invasive analysis of human biomarkers for disease.
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