Master thesis in biophotonics

2016-2017 Thesis project proposal

High resolution Pulsed Thermal imaging for monitoring of hyperthermal therapy at cellular level

Technology - Medical Physics. Hyperthermic therapy combined to chemotherapy helps in limiting the toxicity of the latter by reducing the amount of chemotherapic agents per treatment. To develop this new class of hyperthermic/chemotherapeutic nanodrugs, we need to careful study their interactions with cells, their selectivity for cancer cells and their biodistribution. Hyperthermia is typically induced by plasmonic nanoparticels (gold-silver-platinum) that, irradiated in the near infrared (NIR), induce a thermal load in the surrounding. It is essential to measure the spatial distribution and the amplitude of the induced temperature increase. The temperature detection can be done with thermocameras or needle thermocouples. In any case it is limited I spatial resolution to 2-4 mm, too low to studye the localization of plasmonic, thermoresponsive, nanoparticles within or on the external membrane of cells. The aim of this thesis is to develop a new method based on pulsed, highly localized, NIR irradiation of a thermoresponsive sample. From the spatial dependence of the temperature increases and its relative phase with respect to the excitation pulse, we will be able to gain information on the spatial distribution of the thermoresponsive material at a spatial resolution that is determined by the size of the excitation NIR spot and the thermal diffusivity of the sample. The aim is therefore to reach spatial resolution of the order of 0.1 mm, sufficient to study the distribution of thermoresponsive nanoparticles in tissues.
References: ACS 2016
Investigators in charge: Giuseppe Chirico, Mykola Borzenkov

Adaptive Optics Non-linear excitation microscopy for high resolution in-vivo imaging

The histo-pathological analysis is performed on ex-vivo samples: tissue sections are explanted and stained with standard dyes. The analysis is performed by trained histo-pahtologist, and is largely qualitative and subjective. In order to overcome these limitations and lower the risk of fake negative results, we should perform quantative analysis by means of optical fluorescence microscopy, possibly in-vivo. However this analysis is limited by the large scattering arising from the tissues, and particularly from the skin (dermis and epidermis). Two-photon optical microscopy already lower the scattering issues by employing near infrared radiation. However this is not sufficient to get cellular resolution sub-cute. The aim of the thesis is therefore to implement phase aberrations corrections in an optical scanning two-photon microscope. This will be obtained by inserting an active diffractive element, in this case a Spatial Light Modulator (SLM), in the excitation path of the microscope. Through the collaboration with the CNR laboratories in Padua, it will be possible to compare the performances of the SLM active reflective element with a refraction active element, a deformable lens developed in the CNR laboratories by Dr. Bonora.
References: Adaptive Optics review
Investigators in charge: Laura Sironi, Giuseppe Chirico

References: ACS 2016
Investigators in charge: Giuseppe Chirico, Mykola Borzenkov

Ink-jet printing of gold nanoparticles for scaffolds for neuron cells growth

Neurons, as well as other cell lines, preferentially grow on nanostructured substrates. Recent studies have shown that a slight (few degrees) increase in temperature can induce neural activity and cellular differentiation of stem neural cells. The aim of this thesis is to develop methods to build thermo-responsive nanostructured patterns able to induce localized neural growth and differentiation. The applications of this technology will be in the field of the reconstitution of neural tissues after damages. We will ink-jet print branched gold nanoparticles, which have large hyperthermial effect, on polymeric biocompatible layers, and measure the efficiency of the growth of neural cells and fibroblasts (used as a reference cell line) on the printed substrates. This project is in collaboration with the Univeristy of Pavia (prof. Piersandro Pallavicini) and with the University of Turku (Finlandia).
References: Applied Material 2016
Investigators in charge: Mykola Borzenkov, Maddalena Collini, Giuseppe Chirico

Correlation Spectroscopy and Imaging for the characterization of hydrogels

The gels are composed of materials which under specific chemical or physical stimuli undergo a transition from liquid state to a state in which the relative diffusion of molecular compounds is limited. The hydrogels have a very high content of water and for this reason have many applications in biology and biotechnology. The structural and elastic properties of the hydrogels make them particularly suitable for applications such as drug delivery and tissue engineering (for example, scaffolds for cell growth and tissue). In this thesis the candidate will use correlation spectroscopy and microscopy for the characterization of the structural and elastic properties of hydrogels based on collagen and hyaluronic acid. Hydrogels can mimic the chemical and structural properties of the extracellular matrix, which is particularly dense in the case of solid tumors, strongly limiting the passage of drugs within them. In order to change the properties of this extracellular matrix and increase the penetration of drugs into the tumor mass, we will also use gold nanoparticles, also decorated with enzymes able to digest the matrix itself. The gold nanoparticles, due to their optical and chemical-physical characteristics, may then be used as probes of structure and modifying agents of the same. In fact the hyperthermal properties of the gold nanoparticles, induced by near IR laser irradiation, will offer us an additional method to modify the structure of the matrix. The long term aim of the project is to evaluate the effects of these nanoparticles on tumor models of breast cancer in-vitro and in-vivo. Collaboration with Prof. Cipolla (Department of Biotechnology and Biosciences)
Investigators in charge: Laura Sironi, Maddalena Collini, Laura D'Alfonso

Diffractive Microscopy for the cellular dynamics and cellular networks

Project in Biophysics applied to neurophysiology and to cellular networks. The aim is to optimize an optical setup based on an active diffractive element, a spatial light modulator, that can create an arbitrary pattern on the focal plane of a microscope. The applications are directly in neurophysiology and on the cell sorting in microfluidic setups for the detection of rare pathologies.
References: Neurophotonics 2015
Investigators in charge: Giuseppe Chirico, Maddalena Collini, Nicoló Ceffa

Holographic Microscopy for microfluidics developments

This is a project on holographic microscopy applied to the study of the flow of micro-particles and/or cells in-vitro. We want to develop the technology needed to couple an optical holography setup with microfluidic channel patterns. The aim is to analyze single cells while passing through a mirochannel 100-200 micrometers wide exploiting their scattering and therefore in a label-free approach. A first part of the thesis will be devoted to the techniques to print molds for the microchannel printing and for the development of simple micro-systems to be used as model of cells: giant unilamellar vescicles. A second step will be devoted to the coupling of the holographic microscope to the microfluidic chip. The applications of this setup will be in the field of cell sorting for cellular genotypic and phenotypic analysis.
References: Jetting Giant Unilamellar Vescicles
Investigators in charge: Giuseppe Chirico, Maddalena Collini, Nicoló Ceffa

In-vivo Flow studies by Fluorescence Correlation Imaging

We want to exploit a novel method (FLICS, FLow Image Correlation Spectroscopy) recently developed in our laboratory to extract flow speeds in complex vessel networks from a single raster-scanned optical xy-image, acquired in vivo by confocal or two-photon excitation microscopy. Fluorescent flowing objects produce diagonal lines in the raster-scanned image superimposed to static morphological details. The flow velocity is obtained by computing the Cross Correlation Function (CCF) of the intensity fluctuations detected in pairs of columns of the image. The analytical expression of the CCF has been derived by applying scanning fluorescence correlation concepts to drifting optically resolved objects and the theoretical framework has been validated in systems of increasing complexity. The power of the technique is in the possibility to measure blood flow in microcirculatory system while mapping simultaneously the capillary bed from a single xy-image. We want to apply this method to flow blood in neural vessels at high spatial and temporal resolution in collaboration with the Rehovot Institute in Israel.
References: FLICS imaging
Investigators in charge: Laura Sironi, Maddalena Collini, Laura D'Alfonso