Development of a Spectral-Focusing Coherent Antistokes Raman Scattering Micro-spectrometer (SFM-CARS)

Progetti locali
Ente finanziatore
Settore ERC
PE4_1 - Physical chemistry
Lapini Andrea

Aree / Gruppi di ricerca

Partecipanti al progetto

Descrizione del progetto

Brief description of the proposal 

The project entitled “Development of a Spectral-Focusing Coherent Antistokes Raman Scattering Micro-spectrometer (SFM-CARS)” aims to implement the non-linear spectral-focusing coherent antistokes Raman Scattering (SF-CARS) imaging technique. This imaging technique exploits the third-order interaction between two femtosecond synchronous laser pulses and the sample to generate, when the frequency difference between the two pulses is resonant with a molecular vibration, an amplified Raman signal (10^5 with respect to the spontaneous Raman effect) [1]. The high amplification factor allows to take a hundred microseconds to acquire a 150 cm-1 wide portion of the spectrum [2], allowing to record a hyper-spectral image of a sample with 512x512 points in just over 20 seconds. Due to the Raman-stimulated interaction underlying SF-CARS, no fluorescent markers are used as sensitizers of the substrate to be characterized. This approach allows to considerably expand the kind of samples that can be characterized by means of the micro-spectrometer. This imaging technique finds application both in the field of materials science and in the field of biosciences [2]. Within the field of life sciences, SFM-CARS would allow a significant boost to a collaboration that the PI has with the Polytechnic of Turin (see attached support letter), in the specific context of the processes of direct reprogramming of cardiac fibroblast. In this framework, the interaction that occurs in 3D cell cultures between cells and scaffolds is of fundamental importance. In fact, it has been widely demonstrated [3] that the rigidity of the matrix (scaffold) used to grow fibroblasts has a strong influence on the efficiency of the reprogramming process. Implementing the new mirco-spectrometer thanks to SFM-CARS would allow the contemporary study of the scaffold (fibrin gel), of the cells and the characterization of their interaction without fluorescent markers. Furthermore, within the hot-topics identified by the PNNR, SFM-CARS would allow the study of microplastics in different types of substrates. Thanks to the ability to collect hyper-spectral images based on Raman spectra, SFM-CARS would allow to differentiate the kind of plastic material through the implementation of clustering algorithms. Photonic crystal fibers will be used to generate the pulses at the right frequency with respect to the marker molecular vibrations, this configuration of SFM-CARS will allow in the future to develop the generation of the Stimulated Raman signal using Entangled photons, pushing the micro-spectrometer towards quantum imaging. Two different femtosecond laser sources will be tested: in Chemistry and in Engineering department.

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