Date
2022-05-18
Attachments
pic.png
Reliable diagnostics at the tip of your finger Direct and sensitive analysis
of clinical samples for point-of-care diagnostics |
Biomarkers
are components that may be present in biological samples and are related to specific
diseases. Therefore, doctors can analyze biological samples from a patient to check
their health condition or to monitor the progress of a specific therapy.
Typically, these samples need to be purified and diluted before the analysis, and
current medical diagnostic techniques rely on healthcare facilities and
laboratories for these routine analyses. This is a lengthy process that
requires trained personnel and expensive instrumentation to extract, transport,
store, process, and analyze the samples in centralized locations. Moreover,
during a period of global crisis like the ongoing pandemic, the pressure of thousands
of analysis requests can saturate and collapse the healthcare system.
On
the other hand, point-of-care devices, which are small automated instruments, are
capable of performing diagnostics in decentralized locations and can provide quick
answers. One example of such a device is the glucose meter that people with
diabetes use to monitor their sugar levels in the blood. These devices can
overcome the inherent limitations of having to process a sample through a centralized
system, empowering anyone to be able to monitor their health from home, simply
using a tiny blood sample extracted with a fingerprick.
However,
the development of these devices has been burdened by the technical challenges related
to measuring biological samples. Biomarkers for some diseases and infections
are only present in the samples in very small amounts, which in turn imposes
the challenge to develop extremely sensitive detection techniques. While
increasing the surface area of the biosensor can increase the sensitivity of the
instrument, these surfaces tend to be quickly clogged and contaminated, rendering
them unusable.
To
this end, the team led by Professor CHO,
Yoon-Kyoung at the Center for Soft
and Living Matter within the Institute for Basic Science (IBS) in Ulsan, South
Korea recently developed a biosensor using a method to generate nanostructured
and nanoporous surfaces. This combined strategy not only provides the sensor with
an unprecedented sensitivity but also makes it resistant to fouling by
proteins.
While
previously there has been no known method to reliably create electrodes using
such nanostructured and nanoporous substrates, the team reported a simple
method to generate such materials. The mechanism is based on the application of
electric pulses to a flat gold surface in the presence of sodium chloride and a
surfactant that can form micelles in solution. These electric pulses drive a preferent
reaction to etch and redeposit gold from the surface and, in turn, grow
nanostructures and form the nanopores (Figure 1). The use of surfactant in the
form of micelles is essential to the success of this strategy since it prevents
the material that is being etched from diffusing away during the process, so it
can be redeposited.
The
formation of these nanostructures yielded a large surface area which was
beneficial for increasing the sensitivity of the assays, whereas the formation
of nanopore substrates was ideal to prevent contamination from the biological
samples. Both the nanostructures and the nanopores' combined benefits were key
to the success of this strategy, which could be applied for the direct analysis
of clinical plasma samples.
The
researchers further demonstrated this new technology by building a biosensor
for the detection of prostate cancer. The electrode was sensitive enough to
discriminate between a group of prostate cancer and healthy donors using only a
tiny amount of blood plasma or urine samples. No dilution or preprocessing
steps were used, which means that the technology could easily be used for the point-of-care
diagnosis of cancer.
Professor
Cho stated, “We believe that this technology is essential for the future
development of point-of-care devices and diagnostic tests that work with
biological samples. The capability to detect low concentrations of relevant
biomarkers with robust performance opens a door to possibilities in the field
of diagnostics for cancer, pathogens, and other diseases.”
The
findings of this research have been published in Advanced Materials (IF:
30.849) on May 17th, 2022 and the associated illustration was
selected for the frontispiece in the current issue.
Figure
1. Mechanism
to generate nanostructured and nanoporous gold surfaces based on the
preferential etch and deposition of the substrate using a surfactant that forms
micelles in solution, sodium chloride, and a gold salt. Applying electric
pulses, first, chloride is adsorbed on the surface, then gold is etched away
but captured by the surfactant micelles. Finally, it is redeposited on the
substrate growing the nanostructures in the process. At the bottom, scanning
electron micrographs show the formation of nanostructures and nanopores on the
surface throughout the process.
Notes for editors
- References
Jonathan
Sabaté del Río, Hyun-Kyung Woo, Juhee Park, Hong Koo Ha, Jae-Ryong Kim, Yoon-Kyoung Cho. “SEEDING to Enable Sensitive Electrochemical
Detection of Biomarkers in Undiluted Biological Samples”. Advanced Materials. DOI: 10.1002/adma.202200981
- Media Contact
For
further information or to request media assistance, please contact Yoon-Kyoung Cho at
the Center for Soft and Living Matter, Institute for Basic Science (IBS) (ykcho@unist.ac.kr) or William I. Suh at the IBS Public
Relations Team (willisuh@ibs.re.kr).
- About the Institute for Basic Science (IBS)
IBS was
founded in 2011 by the government of the Republic of Korea with the sole
purpose of driving forward the development of basic science in South Korea. IBS
has 1
research institute and 34 research centers as of May 2022. There are eleven physics, four mathematics, seven chemistry, seven life science, one earth science, and five
interdisciplinary research centers.