Korean researchers have developed a liquid biopsy technology using an inexpensive sensor that can be washed and reused, potentially lowering the high costs of liquid biopsy procedures.
A research team led by Professor Kim Myung-soo of the Department of Electrical and Electronic Engineering at Ulsan National Institute of Science and Technology (UNIST) announced on the 12th that they jointly developed a reusable, high-sensitivity liquid biopsy sensor using molybdenum disulfide (MoS2) and radio frequency (RF) technology, in collaboration with Professor Shin Woo-jung's team at KAIST and Professor Kang Joo-hoon's team at Yonsei University.
Liquid biopsy is a technology that detects cancer by identifying DNA fragments floating in blood or body fluids without removing actual tissue. However, existing testing methods have been costly because detection sensors were either single-use or expensive to manufacture.
The molybdenum disulfide sensor developed by the research team can be reused up to five times simply by washing it in a special solution. Manufacturing is also straightforward and inexpensive—the process only requires applying molybdenum disulfide ink to a substrate, spinning it, and evaporating the solvent from the ink.
Diagnosis involves dropping patient body fluid onto the sensor and then applying radio frequency waves to observe the reaction. The principle works by detecting changes in permittivity and resistance that occur when target DNA attaches to the sensor, which shifts the resonance frequency of the RF signal.
The developed sensor specifically detects "single-strand DNA," which existing genetic analysis technologies have often missed. Single-strand DNA is a biomarker found in high concentrations in patients with terminal cancer or lymph node metastasis. DNA typically exists in a double helix form, with two single strands facing and bonding with each other.
In experiments, the sensor accurately detected DNA fragments of the 'AluSx1' gene, a cancer diagnostic marker, at concentrations as low as 154.67 nM (nanomolar).
The special solution used for cleaning the sensor contains complementary bases. The DNA double helix is a structure formed by molecules called bases facing and bonding with each other, with specific pairings—complementary combinations—that are predetermined. When single-strand DNA attached to the sensor surface encounters its matching pair in the cleaning solution and bonds, it completes the double helix, and the double helix DNA naturally detaches from the sensor without additional processing.
The study was led by Professors Kim Myung-soo and Shin Woo-jung as corresponding authors, with UNIST researcher Lee Seung-chan and KAIST researcher Choi Eun-ho as first authors.
The joint research team stated, "By enabling low-cost detection of single-strand DNA closely linked to cancer metastasis, we expect to dramatically reduce the costs of early diagnosis and prognosis monitoring for cancer metastasis in actual clinical settings in the future." They added, "We plan to develop this into self-diagnostic devices and smart healthcare systems that can easily manage cancer prognosis at home, beyond hospitals."
This research was supported by the National Research Foundation of Korea's Individual Basic Research (Early Career Research), National Agenda Basic Research, Basic Research Lab Support Program, BRIDGE Convergence R&D Program, and the Institute for Information & Communications Technology Planning & Evaluation (IITP)'s Regional Intelligence Innovation Talent Development Program. The findings were published online on January 22nd in "Sensors and Actuators B: Chemical," an international academic journal in the sensor field.