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The advancements in PCR genetic analysis have gained considerable attention, particularly in the context of COVID-19, prompting researchers to explore alternative methods that bypass traditional amplification techniques.
In a groundbreaking development, scientists from Osaka Metropolitan University have unveiled a novel light-induced DNA detection technique utilizing heterogeneous probe particles. This method promises ultra-sensitive and rapid genetic analysis without the reliance on PCR amplification, offering the potential for quicker, more cost-effective, and accurate testing across various fields, including medicine, environmental science, and portable diagnostics.
Genetic testing plays a vital role in detecting alterations in DNA, which is crucial for diagnosing infectious diseases, identifying early-stage cancer, ensuring food safety, and examining environmental DNA. Traditionally, PCR (polymerase chain reaction) has been regarded as the benchmark for such analysis. The term “PCR” has been widely recognized since the onset of the pandemic; however, those familiar with the method understand its limitations, such as high costs, lengthy processes, and dependence on specialized laboratories and personnel.
Lead authors Shuichi Toyouchi, Project Lecturer, Prof. Shiho Tokonami, Deputy Director, and Takuya Iida, Director at Osaka Metropolitan University’s Research Institute for Light-induced Acceleration System (RILACS), emphasize that their innovative approach enables DNA detection without the complexities associated with PCR.
The new technique diverges from traditional PCR by directly detecting DNA through an enhanced concentration and specificity process utilizing strong optical forces and a photothermal effect, rather than amassing millions of copies of DNA sequences.
Central to this method is a system employing heterogeneous probe particles, which include gold nanoparticles and polystyrene microparticles. These probes consist of short, known DNA sequences that hybridize, or bond, with matching sequences in target DNA. The binding, known as DNA hybridization, allows for detection through fluorescence, indicating successful pairing.
The research team employs laser light to illuminate a solution containing both the target DNA and the probe particles. When the size of the particles aligns with the laser’s wavelength, a process called Mie scattering occurs, generating optical forces that propel the particles and expedite DNA hybridization. The gold nanoparticles absorb the laser energy, leading to localized heating that further boosts the specificity of the hybridization process.
“Our technique shows immense promise for precise mutation detection, achieving a sensitivity level that is an order of magnitude higher than that of digital PCR, all within approximately five minutes of laser irradiation,” the researchers noted.
By eliminating the PCR amplification requirement, this innovative method not only reduces costs but also streamlines the testing process and accelerates result delivery. This makes genetic analysis much more accessible for applications in everyday life, ranging from healthcare and food safety to environmental monitoring and personal health tracking.
“We envision applying this PCR-free technology to develop highly sensitive cancer diagnostics, advance quantum life science, and facilitate at-home or environmental DNA testing,” Iida added.
The findings from this research were published in ACS Sensors.
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