Development of novel speckle OCT analysis applied to the study of dynamic processes in microfluidic devices and animal models

• Grant number: 19/19465-0
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): July 01, 2020
• Effective date (End): December 31, 2021
• Field of knowledge: Engineering - Biomedical Engineering
• Principal Investigator: Anderson Zanardi de Freitas
• Grantee: Lucas Ramos de Pretto
• Home Institution: Instituto de Pesquisas Energéticas e Nucleares (IPEN). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 13/26113-6 - Micromachining with ultrashort laser pulses applied to the production and control of optofluidic circuits, AP.TEM

Abstract

This study proposal is focused on the analysis of speckle fluctuations on Optical Coherence Tomography (OCT) signal intensity, aiming at exploiting its properties for flow analysis. This type of analysis has potential applications in the biomedical field for both, microfluidic device fabrication as well as diagnostic methods. The use of microfluidics in biomedical applications presents advantages such as the reduction of sample volume needed and the possibility of integrating many different processes in a single microdevice - for drug testing or fabrication, and even for simulating complex biological functions, as the microvascular network. Still, development of those microcircuits require proper design of the microchannels, to create specific characteristics, such as turbulent flow for reagent mixture. Few techniques are capable of inspecting the flow dynamics inside the microchannels with enough sensitivity and good resolution. Speckle-based techniques developed for OCT enable the non-contact acquisition of flow dynamics data in 3D. We propose the non-invasive investigation of microflow dynamics and characterization using novel autocorrelation analysis of speckle in OCT, providing a feedback mechanism for microcircuits development in a fast and reliable manner. We aim to stablish a feedback methodology for microchannel fabrication using femtosecond laser pulses. OCT is also widely used for biological in vivo applications, and the speckle fluctuations may be used for angiographic investigations. One of those investigations is the study of vascular changes due to functional activation in the brain. The vascular-induced fluctuations are rapidly occurring, however slow fluctuations (as the so-called intrinsic optical signal) can also present relevant information of brain activity. The acquisition sampling (both spatial and temporal) plays an important role on how both of these fluctuations may be analyzed, since frequency filters are intrinsically applied and the speckle and voxel sizes impact on the detectable dynamics. We propose an extensive study on different in vivo occurring brain dynamics under different sampling conditions, to analyze the effects of spatial and temporal filtering on OCT speckle, and how it may be used to improve the analysis of stimulus response in the brain. Allied to our novel autocorrelation analysis, this could enable new diagnostic techniques. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DE PRETTO, LUCAS RAMOS; AMARAL, MARCELLO MAGRI; DE FREITAS, ANDERSON ZANARDI; RAELE, MARCUS PAULO. Nondestructive evaluation of fused filament fabrication 3D printed structures using optical coherence tomography. RAPID PROTOTYPING JOURNAL, v. 26, n. 10, p. 1853-1860, NOV 3 2020. Web of Science Citations: 0.