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.
