Multimodal and Integrated Approach for the Detection and Characterization of Nanoparticles Embedded in Polymeric Systems*

We have assembled a collaborative team of researchers to devise and implement an integrative, optical-based approach for precise detection, accurate identification, and in-situ characterization of specific biomacromolecules embedded in various biologically-relevant matrices. Our overarching goal is the development and application of high-resolution optical-based techniques such as laser-induced breakdown (LIBS) spectroscopy, dynamic light scattering, Raman and FTIR spectroscopies, fluorescence correlation spectroscopy, and 4-D fluorescence microscopy to investigate structural changes of concentrated biopolymeric solutions and biogels and in-situ movements and interactions of nanoparticles dispersed in these systems.  Here, we present results of studies conducted with Ficoll and Polyethylene glycol solutions (up to 1000 mg/ml) as models of water-soluble branched and linear polymeric systems.  We measured changes of their spectral properties and diffusion of various nanosized probes (e.g. fluorophores, proteins, and nanobeads).  We combined the intensity correlation analysis, principal component analysis, and first-order derivative method to assess changes of the Raman peaks associated with the vibrational modes of the molecules with concentration.  Also, we determined the diffusion times of the nanoprobes as a function of the concentration of the host polymeric matrix.  Altogether, the results demonstrate how the techniques and the data-analysis allow to decipher the host-host interactions and the nanoprobe-host interactions.