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Updated: Feb 16, 2026

Isolation of Cancer Stem Cells From Human Prostate Cancer Samples
Published on: March 14, 2014
Long-range two-photon scattering spectroscopy ruler for screening prostate cancer cells
Sudarson Sekhar Sinha1, Dilip K Paul1, Rajashekhar Kanchanapally1
1Department of Chemistry and Biochemistry , Jackson State University , Jackson , MS , USA .
Scientists developed long-range two-photon scattering (TPS) spectroscopy rulers. These novel optical rulers extend the working window to 25 nm, significantly surpassing current FRET rulers for biological applications.
Area of Science:
- Nanotechnology
- Spectroscopy
- Biophysics
Background:
- Optical rulers are crucial for studying biological activity across disciplines.
- Current Förster Resonance Energy Transfer (FRET) rulers have a limited optical window of 10 nm.
- There is a critical need for long-range optical rulers to monitor real-life biological processes.
Purpose of the Study:
- To design and demonstrate long-range two-photon scattering (TPS) spectroscopy rulers.
- To overcome the distance limitations of existing optical ruler technologies.
- To enable precise measurements in complex biological systems.
Main Methods:
- Fabrication of gold nano-antenna structures separated by rigid double-strand DNA molecules.
- Utilizing two-photon scattering (TPS) spectroscopy for distance measurements.
- Employing angle-resolved TPS measurements and Finite-Difference Time-Domain (FDTD) simulations to elucidate mechanisms.
- Developing aptamer-based assays for cell detection.
Main Results:
- Demonstrated a TPS spectroscopy ruler with a working window up to 25 nm, more than double that of FRET rulers.
- Investigated the mechanism behind the long-range capability of TPS rulers.
- Successfully screened prostate-specific membrane antigen (PSMA) positive prostate cancer cells at concentrations as low as 5 cells/mL.
- Distinguished between PSMA (+) cancer cells and PSMA (-) normal skin cells using the TPS ruler assay.
Conclusions:
- Long-range TPS spectroscopy rulers offer a significant advancement over existing optical rulers.
- The developed TPS ruler assay demonstrates high sensitivity and specificity for cancer cell detection.
- This technology holds promise for understanding chemical and biological processes and advancing diagnostics.
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