Two-in-one sensor of refractive index and Raman scattering using hollow- core microstructured optical waveguides for colloid characterization

Hollow- core microstructured optical waveguides (HC- MOW) have recently emerged in sensing technologies, including the gas and liquid detection for industrial as well as clinical applications. Antiresonant HC- MOW provide capabilities for applications in refractive index (RI) sensing, while the long optical path for analyte- light interaction in HC- MOW leads to increased sensitivity of sensor based on Raman scattering signal measurements. In this study, we developed a two- in- one sensor device using HC- MOW for RI and Raman scattering detection. The performance of the sensor was evaluated by characterizing protein- copolymer multicomponent colloids, specifically, bovine serum albumin (BSA) and poly(N - vinyl- 2 - pyrrolidone- co- acrylic acid) P(VP- AA) nano- sized complexes and microbubbles of the corresponding shell. Monocomponent solutions showed linear dependencies of RI and characteristic Raman peak intensities on mass concentration. Multicomponent Raman sensing of BSA@P(VP- AA) complexes and microbubbles revealed that changes in P(VP- AA) characteristic peak intensities can describe interactions between components needed to produce colloid systems. RI sensing of multicomponent colloids demonstrated linear dependence on total mass concentrations for BSA@P(VP- AA) complexes, while corresponding BSA@P(VP- AA) microbubbles can be detected with concentrations as high as 4.0 x 10(8) MB/mL. Therefore, the developed two- in- one sensor of RI and Raman scattering can be used the robust characterization of albumin- based colloids designed for therapeutic and diagnostic needs.