Biosensing based on two-photon fluorescence measurements through optical fibers

Area of Science:

• Biomedical Optics
• Fiber Optic Sensing
• Fluorescence Microscopy

Background:

• Two-photon fluorescence detection enables deeper tissue imaging and reduced photobleaching.
• Optical fibers offer a flexible and minimally invasive platform for in-situ measurements.

Purpose of the Study:

• To develop and validate a new fiber-optic sensing scheme for two-photon fluorescence detection.
• To assess the performance of single-mode versus multimode fibers for this application.
• To demonstrate the utility of the system for biological sensing, specifically drug uptake in cancer cells.

Main Methods:

• Femtosecond laser pulses were delivered through an optical fiber for nonlinear excitation.
• Emitted fluorescence was collected through the same optical fiber.
• Single-mode and multimode fibers were compared for detection efficiency.
• Drug delivery agent uptake into cultured cancer cells was measured.

Main Results:

• The novel fiber-optic scheme successfully achieved two-photon fluorescence detection.
• Single-mode fibers demonstrated higher detection efficiency compared to multimode fibers.
• The system proved effective in measuring targeted drug delivery agent uptake in cancer cells.

Conclusions:

• A new, efficient fiber-optic sensing method for two-photon fluorescence detection has been established.
• Single-mode optical fibers are advantageous for this sensing modality.
• This technology holds promise for real-time monitoring of cellular processes and drug delivery.