Cellular healthcare is an approach that goes beyond clinical laboratory testing to identify the location of specific cancer cells and aid in treatment decisions
Advances in synthetic biology and genetic engineering are leading to development of bacterial biosensors that could eventually aid pathologists and clinical laboratories in diagnosis of many types of cancers.
One recent example comes from researchers at the University of California San Diego (UCSD) who worked with colleagues in Australia to engineer bacteria that work as “capture agents” and bind to tumorous material.
The KRAS gene is associated with colorectal cancer. The researchers named their development the Cellular Assay for Targeted CRISPR-discriminated Horizontal gene transfer (CATCH).
CATCH successfully detected cancer in the colons of mice. The researchers believe it could be used to diagnose cancers, as well as infections and other diseases, in humans as well, according to a UCSD news release.
“If bacteria can take up DNA, and cancer is defined genetically by a change in its DNA, then, theoretically, bacteria could be engineered to detect cancer,” gastroenterologist Daniel Worthley, PhD, a cancer researcher at Colonoscopy Clinic in Brisbane, Australia, told MedicalResearch.com. This research could eventually provide clinical laboratories and anatomic pathologists with new tools to use in diagnosing certain types of cancer. (Photo copyright: Colonoscopy Clinic.)
Tapping Bacteria’s Natural Competence
In their Science paper, the researchers acknowledged other synthetic biology achievements in cellular biosensors aimed at human disease. But they noted that more can be done by leveraging the “natural competence” skill of bacteria.
“Biosensors have not yet been engineered to detect specific extracellular DNA sequences and mutations. Here, we engineered naturally competent Acinetobacter baylyi (A. baylyi) to detect donor DNA from the genomes of colorectal cancer cells, organoids, and tumors,” they wrote.
“Many bacteria can take up DNA from their environment, a skill known as natural competence,” said Rob Cooper, PhD, co-first author of the study and a scientist at US San Diego’s Synthetic Biology Institute, in the news release. A. baylyi is a type of bacteria renowned for success in doing just that, the NCI article pointed out.
This enabled them to explore “free-floating DNA sequences on a genomic level.”
Those sequences were compared to “known cancer DNA sequences.”
A. baylyi (genetically modified) was tested on its ability to detect “mutated and healthy KRAS DNA.”
Only bacteria that had “taken up mutated copies of KRAS … would survive treatment with a specific drug.”
“It was incredible when I saw the bacteria that had taken up the tumor DNA under the microscope. The mice with tumors grew green bacterial colonies that had acquired the ability to be grown on antibiotic plates,” said Josephine Wright, PhD, Senior Research Fellow, Gut Cancer Group, South Australian Health and Medical Research Institute (SAHMRI), in the news release.
Detecting DNA from Cancer Cells In Vitro and in Mice
Findings in vitro and in mice include the following:
The engineered bacteria enabled detection of DNA with KRAS G12D from colorectal cancer cells made in the lab, NCI reported.
When mice were injected with colorectal cancer cells, the researchers’ technology found tumor DNA, Engadget reported.
The study adds to existing knowledge of horizontal gene transfer from bacteria to bacteria, according to UCSD.
“We observed horizontal gene transfer from the tumor to the sensor bacteria in our mouse model of colorectal cancer. This cellular assay for targeted, CRISPR-discriminated horizontal gene transfer (CATCH) enables the biodetection of specific cell-free DNA,” the authors wrote in Science.
“Colorectal cancer seemed a logical proof of concept as the colorectal lumen is full of microbes and, in the setting of cancer, full of tumor DNA,” gastroenterologist Daniel Worthley, PhD, a cancer researcher at Colonoscopy Clinic in Brisbane, Australia, told MedicalResearch.com.
Finding More Cancers and Treatment
More research is needed before CATCH is used in clinical settings. The scientists are reportedly planning on adapting CATCH to multiple bacteria that can locate other cancers and infections.
“The most exciting aspect of cellular healthcare … is not in the mere detection of disease. A laboratory can do that,” wrote Worthley in The Conversation. “But what a laboratory cannot do is pair the detection of disease (a diagnosis) with the cells actually responding to the disease [and] with appropriate treatment.
“This means biosensors can be programmed so that a disease signal—in this case, a specific sequence of cell-free DNA—could trigger a specific biological therapy, directly at the spot where the disease is detected in real time,” he added.
Clinical laboratory scientists, pathologists, and microbiologists may want to stay abreast of how the team adapts CATCH, and how bacterial biosensors in general continue to develop to aid diagnosis of diseases and improve ways to target treatment.
These new insights might lead to a new line of clinical laboratory testing, particularly if the results could guide the patient to microbiome-based repellents that would remain effective for months once applied
Researchers are beginning to identify what compounds make individuals more attractive to mosquitos. That is a first step in the development of a biomarker that could be developed into a clinical laboratory test. Question is: would there be enough consumers wanting to do a lab test to determine if they were highly attractive to mosquitos, thus making this a revenue-generating test for labs?
The SA article reported on their study published in the journal Cell titled, “Differential Mosquito Attraction to Humans Is Associated with Skin-Derived Carboxylic Acid Levels.” The researchers, according to SA, found that individual humans have “a unique scent profile made up of different chemical compounds” and that “mosquitoes were most drawn to people whose skin produces high levels of carboxylic acids.” The researchers also found that “attractiveness to mosquitoes remained steady over time, regardless of changes in diet or grooming habits.”
At a minimum, there would be widespread consumer interest to at least understand why some individuals get more mosquito bites than others. What may be of particular interest to microbiologists is the statement by molecular biologist Omar Akbari, PhD, of the University of California, San Diego, who told Scientific American that by “taking human-colonizing skin bacteria … and engineering them in such a way that they can either express a repellent compound or be able to degrade something that’s attractive,” a mosquito repellant could be developed that would last for months once applied.
“This study clearly shows that these acids are important,” neurogeneticist Matthew DeGennaro, PhD (above), told CNN. “… how the mosquitoes perceive these carboxylic acids is interesting because these particular chemicals … are hard to smell at a distance. It could be that these chemicals are being altered by … the skin microbiome … if we understand why mosquitoes find a host, we can design new repellents that will block the mosquitoes from sensing those chemicals, and this could be used to improve our current repellents.” Clinical laboratory testing will be needed to produce biomarkers for developing such improved repellents. (Photo copyright: Laboratory of Tropical Genetics.)
Clinical Laboratory Testing Needed to Identify Levels of Carboxylic Acids
To complete their study, the researchers had 64 participants wear nylon stockings for six hours on their arms to get their unique scent into the fabric. The scent on the stockings was not discernible to the human nose, but it was to the mosquitos.
Two pieces of the nylon were then placed in a closed container with Aedes aegypti mosquitoes. The researchers found that certain samples were more popular with the mosquitos than others. Upon further analysis the researchers found that the most popular samples came from subjects with higher levels of carboxylic acids, and the least popular had the lowest levels. The scientists ran the test with the same participants several times over three years and the results remained largely the same.
Carboxylic acid is an organic compound found in humans in sebum, the oily layer protecting our skin. The level at which humans release carboxylic acid varies from person to person. And there is no discernible way the human nose can determine whether a person has the level of carboxylic acid on the skin that mosquitos find desirable. The answer would need to be determined by a diagnostic test performed in a clinical laboratory.
Although the development of a test to determine someone’s susceptibility to mosquitos may be far away, there could be significant consumer interest in developing such a test.
“The question of why some people are more attractive to mosquitoes than others—that’s the question that everybody asks,” Leslie B. Vosshall, PhD, Chief Scientific Officer, Howard Hughes Medical Institute, who led the research team to find out why some people are more attractive to mosquitos than others, told Scientific American. “My mother, my sister, people in the street, my colleagues—everybody wants to know.” She credits their interest as the inspiration for embarking on the study.
“Understanding what makes someone a ‘mosquito magnet’ will suggest ways to rationally design interventions such as skin microbiota manipulation to make people less attractive to mosquitoes. We propose that the ability to predict which individuals in a community are high attractors would allow for more effective deployment of resources to combat the spread of mosquito-borne pathogens,” the researchers wrote in their Cell paper.
Preventing Spread of Deadly Diseases
Although mosquitos are an annoyance, they also can be dangerous vectors of disease.
“Every bite of these mosquitoes puts people into public health danger. Aedes aegypti mosquitoes are vectors for dengue, yellow fever, and Zika,” Vosshall told CNN. “Those people who are magnets are going to be much more likely to be infected with viruses.”
Further research into these early findings may help develop diagnostic tests to protect against the spread of these diseases and identify individuals who are more attractive to the mosquitos, and therefore, more likely to contract and spread disease.
Being able to identify which individuals are mosquito magnets could help keep individuals safe from dangerous diseases, and development of a better repellent could also make outdoor summer events more bearable for the (unfortunately) popular among the pests. Medical laboratory tests associated with determining an individual’s susceptibility to mosquito bites could give clinical laboratories a new way to add value to consumers and patients.
Researchers surprised that process designed to detect SARS-CoV-2 also identifies monkeypox in wastewater
Early information about an outbreak in a geographical region can inform local clinical laboratories as to which infectious agents and variants they are likely to see when testing patients who have symptoms. To that end, wastewater testing has become a rich source of early clues as to where COVID-19 outbreaks are spreading and how new variants of the coronavirus are emerging.
Ongoing advances in genetic sequencing and digital technologies are making it feasible to test wastewater for infectious agents in ways that were once too time-consuming, too expensive, or simply impossible.
“Before wastewater sequencing, the only way to do this was through clinical testing, which is not feasible at large scale, especially in areas with limited resources, public participation, or the capacity to do sufficient testing and sequencing,” said Knight in a UCSD press release. “We’ve shown that wastewater sequencing can successfully track regional infection dynamics with fewer limitations and biases than clinical testing to the benefit of almost any community.” (Photo copyright: UC San Diego News.)
Same Process, Different Virus
Following August’s declaration of a state of emergency by California, San Diego County, and the federal government, UCSD researchers added monkeypox surveillance to UCSD’s existing wastewater surveillance program.
“It’s the same process as SARS-CoV-2 qPCR monitoring, except that we have been testing for a different virus. Monkeypox is a DNA virus, so it is a bit of a surprise that our process optimized for SARS-CoV-2, which is an RNA virus, works so well,” said Rob Knight, PhD, Professor of Pediatrics and Computer Science and Engineering at UCSD and one of the lead authors of the study in the press release.
According to the press release, RNA sequencing from wastewater has two specific benefits:
It avoids the potential of clinical testing biases, and
It can track changes in the prevalence of SARS-CoV-2 variants over time.
In 2020, at the height of the COVID-19 pandemic, scientists from the University of California San Diego and Scripps Research looked into genetic sequencing of wastewater. They wanted to see if it would provide insights into levels and variants of the SARS-CoV-2 within a specific community.
Individuals who have COVID-19 shed the virus in their stool.
The UCSD/Scripps researchers deployed commercial auto-sampling robots to collect wastewater samples at the main UCSD campus. They analyzed the samples for levels of SARS-CoV-2 RNA at the Expedited COVID-19 Identification Environment (EXCITE) lab at UCSD. After the success of the program on the campus, they extended their research to include other facilities and communities in the San Diego area.
“The coronavirus will continue to spread and evolve, which makes it imperative for public health that we detect new variants early enough to mitigate consequences,” said Knight in a July press release announcing the publication of their study in the journal Nature, titled, “Wastewater Sequencing Reveals Early Cryptic SARS-CoV-2 Variant Transmission.”
Detecting Pathogens Weeks Earlier than Traditional Clinical Laboratory Testing
In July, the scientists successfully determined the genetic mixture of SARS-CoV-2 variants present in wastewater samples by examining just two teaspoons of raw sewage. They found they could accurately identify new variants 14 days before traditional clinical laboratory testing. They detected the presence of the Omicron variant 11 days before it was first reported clinically in the community.
During the study, the team collected and analyzed 21,383 sewage samples, with most of those samples (19,944) being taken from the UCSD campus. They performed genomic sequencing on 600 of the samples and compared them to genomes obtained from clinical swabs. They also compared 31,149 genomes from clinical genomic surveillance to 837 wastewater samples taken from the community.
The scientists distinguished specific viral lineages present in the samples by sequencing the viruses’ complete set of genetic instructions. Mutational differences between the various SARS-CoV-2 variants can be minute and subtle, but also have notable biological deviations.
“Nothing like this had been done before. Sampling and detection efforts began modestly but grew steadily with increased research capacity and experience. Currently, we’re monitoring almost 350 buildings on campus,” said UCSD’s Chancellor Pradeep Khosla, PhD, in the July press release.
“The wastewater program was an essential element of UC San Diego Health’s response to the COVID pandemic,” said Robert Schooley, MD, Infectious Disease Specialist at UC San Diego Health, in the press release. Schooley is also a professor at UCSD School of Medicine, and one of the authors of the study.
“It provided us with real-time intelligence about locations on campus where virus activity was ongoing,” he added. “Wastewater sampling essentially allowed us to ‘swab the noses’ of every person upstream from the collector every day and to use that information to concentrate viral detection efforts at the individual level.”
Monkeypox Added to UCSD Wastewater Surveillance
In August, UCSD officially added the surveillance of the monkeypox virus to their ongoing wastewater surveillance program. A month earlier, the researchers had discerned 10,565.54 viral copies per liter of wastewater. They observed the levels fluctuating and increasing.
On August 2, the scientists detected 189,309.81 viral copies per liter of wastewater. However, it is not yet clear if the monitoring of monkeypox viral loads in wastewater will enable the researchers to accurately predict future infections or case rates.
“We don’t yet know if the data will anticipate case surges like with COVID,” Knight said in the August UCSD press release announcing the addition of monkeypox to the surveillance program. “It depends on when the virus is shed from the body relative to how bad the symptoms are that cause people to seek care. This is, in principle, different for each virus, although in practice wastewater seems to be predictive for multiple viruses.”
Utilization of genetic sequencing of wastewater sampling will continue to develop and improve. “It’s fairly easy to add new pathogens to the process,” said Smruthi Karthikeyan, PhD, an environmental engineer and postdoctoral researcher in Knight’s lab who has overseen wastewater monitoring at UC San Diego. “It’s doable on short notice. We can get more information in the same turnaround time.”
Thus, clinical laboratories engaged in testing programs for COVID-19 may soon see the addition of monkeypox to those processes.
Wearable microneedle sensors that track multiple biomarkers in interstitial fluid are finding their way into chronic disease monitoring and sample collecting for clinical laboratory testing
Wearable devices that replace finger sticks and blood draws for monitoring biomarkers of chronic diseases such as diabetes are the holy grail of non-invasive (or at least minimally invasive) technologies that collect specimens for clinical laboratory testing.
Now, in their quest for alternatives to invasive phlebotomy blood draws, engineers at University of California San Diego’s (UCSD) Center for Wearable Sensors have added their own wearable device to the mix. The scientists developed a “lab-on-the-skin” multi-tasking microneedle sensor that monitors multiple biomarkers simultaneously, according to a UCSD news release.
“This is like a complete lab on the skin,” said Joseph Wang, PhD (above), Distinguished Professor of Nanoengineering at UC San Diego and Director of UCSD’s Center of Wearable Sensors, in a news release. “It is capable of continuously measuring multiple biomarkers at the same time, allowing users to monitor their health and wellness as they perform their daily activities.” UC San Diego’s microneedle patch for monitoring biomarkers of disease certainly would be popular with patients who must regularly undergo painful blood draws for clinical laboratory testing. (Photo copyright: UC San Diego.)
Advantage of Monitoring Multiple Biomarkers in Real Time
While current glucose monitors on the market only measure glucose, the UCSD wearable device also monitors alcohol and lactate, providing other additional information to diabetics when engaged in activities that affect those biomarkers.
For example, UCSD’s microneedle sensor allows diabetics to monitor their glucose level when drinking alcohol, which can lower glucose levels. Additionally, monitoring lactate while exercising also could be beneficial since physical activity influences the body’s ability to regulate glucose.
“With our wearable, people can see the interplay between their glucose spikes or dips with their diet, exercise, and drinking of alcoholic beverages. That could add to their quality of life as well,” said Farshad Tehrani, a nanoengineering PhD graduate researcher in Wang’s lab at UCSD and one of the co-first authors of the study, in the news release.
UC San Diego’s wearable microneedle patch (above) is about the size of a stack of six quarters and simultaneously monitors glucose, alcohol, and lactate levels continuously. It affixes to the skin through a patch of microneedles each about one-fifth the width of a human hair. The microneedles barely penetrate the surface of the skin to sample biomolecules in the interstitial fluid and are not painful. The quarter-sized patch is worn on the upper arm and transmits its data to a smartphone app. The microneedle patch is disposable, and the reusable electronic case is rechargeable using an off-the-shelf wireless charging pad. (Photo copyright: Laboratory for Nanobioelectronics/UC San Diego.)
Other Microneedle Wearable Monitoring Patches
The quest for a painless alternative to in-patient blood draws for many clinical laboratory tests has been ongoing worldwide for years.
In “Researchers Develop ‘Smart’ Microneedle Adhesive Bandage System for Monitoring Sodium, Glucose, pH, and More,” Dark Daily reported on a proof-of-concept study conducted by scientists from Israel and China who developed a “smart” microneedle adhesive bandage that measures and monitors in real time three critical biomarkers that currently require invasive blood draws for medical laboratory tests commonly performed on patients in hospitals.
While further research and validation of studies are needed before UC San Diego’s wearable microneedle sensor patch can be deployed to monitor chronic diseases, it is in good company. Diabetics and other suffers of similar chronic diseases can look forward to a future where they can monitor their health conditions in real time without the need for invasive blood draws and clinical laboratory testing.
Skin patch technologies could enable clinical laboratories to monitor patients’ vitals and report to medical professionals in real time
Pathologists and clinical laboratory leaders have read many Dark Daily ebriefings on the development of skin patches over the years that do everything from monitoring fatigue in the military to being a complete lab-on-skin technology. Now, researchers at the University of California San Diego (UCSD) have developed a wearable patch that can monitor cardiovascular signals and other various biochemical levels in the body simultaneously.
The researchers believe there is enormous potential for such a patch in helping patients monitor conditions such as hypertension or diabetes. They also foresee a scenario where the patch could be used in settings where vitals must be constantly monitored. They hope to develop future versions of the patch that can detect more biomarkers within the body.
“This type of wearable would be very helpful for people with underlying medical conditions to monitor their own health on a regular basis,” Lu Yin, a PhD student and co-first author of the study, told New Atlas. “It would also serve as a great tool for remote patient monitoring, especially during the COVID-19 pandemic when people are minimizing in-person visits to the clinic,” she added.
Combining Precision Medicine with Telehealth and the Internet of Things
About the size of a postage stamp and consisting of stretchy polymers that conform to the skin, the UCSD patch monitors blood pressure and contains sensors that measure different biochemical levels in the body, such as:
The sensors are carefully arranged on the patch to eliminate interference between the signals, noted a UCSD press release.
In their published research, the UCSD researchers wrote of their new skin patch monitoring device, “Intertwined with concepts of telehealth, the internet of medical things, and precision medicine, wearable sensors offer features to actively and remotely monitor physiological parameters. Wearable sensors can generate data continuously without causing any discomfort or interruptions to daily activity, thus enhancing the self-monitoring compliance of the wearer, and improving the quality of patient care.” (Photo copyright: University of California San Diego.)
“Each sensor provides a separate picture of a physical or chemical change. Integrating them all in one wearable patch allows us to stitch those different pictures together to get a more comprehensive overview of what’s going on in our bodies,” said Sheng Xu, PhD, Principle Investigator, Xu Research Group at UCSD, Assistant Professor in the Department of NanoEngineering Department, and a co-first author of the study, in the press release.
The UCSD researchers developed their skin patch to monitor specific biomarkers that can affect blood pressure.
“Let’s say you are monitoring your blood pressure and you see spikes during the day and think that something is wrong,” co-first author Juliane Sempionatto, PhD, a postdoctoral researcher at California Institute of Technology (Caltech) and co-first author of the study, told New Atlas. “But a biomarker reading could tell you if those spikes were due to an intake of alcohol or caffeine. This combination of sensors can give you that type of information,” she added.
The blood pressure sensor sits near the center of the patch and consists of a set of small transducers welded to the patch via a conductive link. Voltage applied to the transducers send ultrasound waves through the body which bounce off arteries and create echoes that are detected by the sensor and converted into an accurate blood pressure reading.
The chemical sensor releases the drug pilocarpine into the skin to induce sweat and then measures the chemicals contained in the sweat to provide readings of certain biochemical levels.
The glucose sensor located in the patch emits a mild electrical current to the body that stimulates the release of interstitial fluid and then reads the glucose level in that fluid.
“The novelty here is that we take completely different sensors and merge them together on a single small platform as small as a stamp,” Joseph Wang, D.Sc, SAIC Endowed Chair, Distinguished Professor of NanoEngineering, Director of the Center for Wearable Sensors at UCSD, and co-author of the study told New Atlas. “We can collect so much information with this one wearable and do so in a non-invasive way, without causing discomfort or interruptions to daily activity.” (Photo copyright: University of Southern California San Diego.)
Skin Patch Measurements Closely Match Those of Traditional Devices
Test subjects wore the patch on their neck while performing various combinations of the following tasks:
exercising on a stationary bicycle,
eating a high-sugar meal,
drinking an alcoholic beverage, and
drinking a caffeinated beverage.
The results of the measurements taken from the patch closely matched measurements collected by traditional monitoring devices such as a:
For now, the patch must be connected to an external power source which transmits the reading to a counter-top machine, but the researchers hope to create a wireless version in the future.
“There are opportunities to monitor other biomarkers associated with various diseases,” Sempionatto said in the UCSD press release. “We are looking to add more clinical value to this device.”
Other Similar Skin Patch Monitoring Technologies
Though an important breakthrough, the UCSD’s device is not the first skin patch monitor to be developed.
Multiple research and clinical studies are underway that hope to prove the accuracy and safety of wearable devices at detecting and monitoring certain health conditions. It’s a worthy goal.
Skin patches, such as the one created at UCSD, could enable clinical laboratories to provide value-added service to medical professionals and patients alike. Medical labs could potentially monitor skin patch readings in real-time and notify physicians and patients of changes in biomarkers that require attention.
Further, as this technology is developed, it will likely find a ready market with the latest generation of consumers who are more willing than previous generations to buy their own diagnostic tests for home use. These “next-generation” healthcare consumers have demonstrated their willingness to use Apple watches, Fitbits, and similar wearable devices to monitor their condition during exercise and other health metrics.
Pathologists and clinical laboratory managers should not overlook the potential for robust consumer demand to accelerate development and market adoption of such skin patches.
