Stimulated Raman Photothermal Microscopy towards Ultrasensitive Chemical Imaging.
Yifan ZhuXiaowei GeHongli NiJiaze YinHaonan LinLe WangYuying TanChinmayee V Prabhu DessaiJi-Xin ChengPublished in: bioRxiv : the preprint server for biology (2023)
Stimulated Raman scattering (SRS) microscopy has shown enormous potential in revealing molecular structures, dynamics and coupling in a complex system 1â€"3 . However, the bond-detection sensitivity of SRS microscopy is fundamentally limited to milli-molar level due to the shot noise and the small modulation depth in either pump or Stokes beam 4 . Here, to overcome this barrier, we revisit SRS from the perspective of energy deposition. The SRS process pumps molecules to their vibrational excited states. The thereafter relaxation heats up the surrounding and induces a change in refractive index. By probing the refractive index change with a continuous wave beam, we introduce stimulated Raman photothermal (SRP) microscopy, where a >500-fold boost of modulation depth is achieved on dimethyl sulfide with conserved average power. Versatile applications of SRP microscopy on viral particles, cells, and tissues are demonstrated. With much improved signal to noise ratio compared to SRS, SRP microscopy opens a new way to perform vibrational spectroscopic imaging with ultrahigh sensitivity and minimal water absorption.
Keyphrases
- label free
- single molecule
- high resolution
- optical coherence tomography
- high speed
- high throughput
- molecular dynamics simulations
- mass spectrometry
- photodynamic therapy
- density functional theory
- sars cov
- air pollution
- induced apoptosis
- transcription factor
- cell death
- oxidative stress
- quantum dots
- gold nanoparticles
- fluorescent probe
- room temperature
- climate change
- tandem mass spectrometry
- simultaneous determination