Fan-Ching Chien *, Kun-Yu Lai, Tsung-Hsun Yang
Department of Optics and Photonics, National Central University, Taoyuan 320, Taiwan
*fcchien@dop.ncu.edu.tw
We developed a single-molecule localization microscopy (SMLM) based on temporal-focusing multiphoton excitation (TFMPE), and single-wavelength excitation is used to visualize the three-dimensional (3D) distribution of fluorophore-labeled subcellular structures in a thick specimen with a nanoscale-level spatial resolution. To eliminate the photobleaching effect of unlocalized molecules in out-of-focus regions for improving the utilization rate of the photon budget in 3D SMLM imaging, SMLM with single-wavelength TFMPE achieves wide-field and axially confined two-photon excitation of fluorophores. The system is capable of 3D TFMPE-SMLM imaging of brain tissue section of a 5XFAD transgenic mouse with the pathological features of Alzheimer’s disease, revealing the distribution of neurotoxic amyloid-beta peptide deposits. Additionally, to capture the target gene quickly in personalized medical treatments, we present a label-free hybrid-free DNA detection by surface-enhanced Raman spectroscopy (SERS), whose performances are boosted by InGaN quantum wells (QWs) and machine learning. This is realized by tuning the energy states of QWs, within which the confined electrons resonate with those vibrating on the oligonucleotide and the roughened aluminum (Al) surface. The QW-Al-DNA resonance promotes many minor SERS signals to the detectable level, allowing the machine to identify four distinct circulating tumor DNAs responsible for pancreatic, thyroid, lung, and breast cancers in 1 h.
關鍵詞：single-molecule localization microscopy, temporal-focusing multiphoton excitation, surface-enhanced Raman spectroscopy, InGaN quantum wells, Alzheimer’s disease, circulating tumor DNAs
