Femtosecond Laser-Assisted Microbubble Technique For Extracellular Vesicle Enrichment And Characterization In Tear Fluid: A Novel Diagnostic Approach For Ophthalmology

Extracellular vesicles (EVs) from tear fluids are of significant interest due to their potential in diagnosing ophthalmological diseases. However, current analytical techniques often lack the sensitivity to effectively isolate and characterize EVs from tear samples. Developing advanced methods for concentration enrichment and detailed characterization of EVs is essential to address these limitations and enhance diagnostic capabilities.

Study was conducted at Centre of Excellence for Biophotonics at Manipal Academy of Higher Education, using the samples collected from Department of opthalmology, Kasturba Medical College.

The Shrinking Surface Bubble Deposition (SSBD) technique using femtosecond laser, provides a more targeted approach by utilizing a micro bubble formation to capture and analyse EVs directly from tear sample. This technique generates bubbles within the sample medium, typically using pulsed lasers in conjunction with plasmonic silver (Ag) nanoparticles. Silver nanoparticles are particularly advantageous due to their strong plasmonic properties, which enhance bubble formation under laser irradiation, aiding in the capture and concentration of extracellular vesicles at the surface of shrinking bubbles. Further, the concentrated Evs were characterized using Micro-Raman Spectroscopy, enabling detailed compositional analysis.

Distinctive Raman peaks associated with EVs were successfully detected, confirming the feasibility of using SSBD for EV concentration enrichment. Optimization of laser parameters allowed effective localization of EVs to a specific spot, enhancing their detection and characterization. The study demonstrated that this approach enables both efficient enrichment and detailed compositional analysis of EVs from tear fluids.

The femtosecond laser-assisted microbubble technique combined with Raman spectroscopy is a promising method for isolating and characterizing extracellular vesicles from body fluids. This approach offers a novel solution for concentrating EVs from diluted solutions, paving the way for improved diagnostic applications in ophthalmology .