Finished PhD

Finished PhD

Studies on the behavior of fluids in the field of laser radiation
PhD:
Mihai Boni
PhD Adviser
Prof. Dr. Mihail-Lucian Pascu
Finished:
2018

Best Doctoral Thesis Award, Exact Sciences and Engineering on 2018, received from the Senate of University of Bucharest

The original results presented in this thesis focus mainly on laser interactions with suspended liquid drops in open air. These studies are interdisciplinary covering several areas of fundamental and technological research, such as: microfluidics, spherical resonators, optofluidics, spontaneous emission amplification effects and / or stimulated emission in optical spectroscopy. The obtained results, thought belonging to fundamentals of physics, have potential applications in: detection in biological systems, tunable micro-lasers, biomedical applications, environment quality monitoring. During these studies, both the resonant and non-resonant interactions at the exposure of suspended droplets to laser pumping beams were monitored and evaluated. Resonant interactions occur when solution components (for example, molecules) of assay medium absorb incident radiation, usually the effects consisting in passing molecules from fundamental singlet state to an excited singlet state. The return of excited molecules to corresponding fundamental singlet states is accompanied by either fluorescence emission, or phosphorescence, or non-radioactive processes. Another possible effect is the dissociation of absorbing molecules and production of new substances derived from parent molecules. This is specific to laser photochemistry. Non-resonant interactions takes place when laser beam is not absorbed by the droplet constituents. Their effects are due to the pressure of light exerted on droplet, to electrostriction forces and to local and/or global thermal changes in the droplet.

Generation and testing the photoreaction products obtained from the exposure of solutions of drugs to laser beams

The discovery of compounds with direct antimicrobial effects obtained by laser irradiation of a drug is a further step in overcoming the gap created in antimicrobial research. Developing new antimicrobial agents by the repurposing of current non-antibiotics could have a major benefit in allowing the extended reuse of existing medicines. The modification of medicine’s molecular structures through laser radiation represents a new approach in chemistry, biology, and pharmacology. The generated photoproducts and their concentrations can be controlled through irradiation process, by choosing the proper laser wavelength, the time and the dose of irradiation. The original contributions of the doctoral thesis represent the combination of both spectroscopic and physico-chemical analytical methods and antimicrobial susceptibility assays to demonstrate that 266 nm irradiated chlorpromazine and thioridazine are suitable candidates in fighting antimicrobial resistance.

Molecular structures modification of medicines exposed to laser radiation, in view of their interaction with biological materials and bicompatible fabrics

Cancer is one of the leading causes of death worldwide with approximately 14 million new cases and 8.2 million cancer-related deaths. Finding ways to diagnose and treat cancer in an early stage is of high importance since the mortality from this disease is highly influenced by its status at the time of diagnostic. One of the main directions in diagnostic pathology is to develop new methods that can provide accurate results at low costs. This project’s scope is related to the development of a label-free imaging device based on quantitative phase imaging (QPI) capable of analyzing cells within malignant or non-malignant tissues and discriminate between them by detecting slight refractive index variations of unstained tissues that are not otherwise possible with usual light microscopy techniques. The device to be developed will be composed of an interferometric set-up capable of providing quantitative information (optical pathlength/tissue density of the sample) about the tissue samples to be evaluated. This label-free method will provide an increased accuracy compared to currently employed methods by correlating the refractive index variation/distribution with the type of analyzed sample.

Molecular structures modification of medicines exposed to laser radiation, in view of their interaction with biological materials and bicompatible fabrics
PhD:
Viorel Vasile Nastasa
PhD Adviser
Prof. Dr. Mihail-Lucian Pascu
Finished:
2012

Cancer is one of the leading causes of death worldwide with approximately 14 million new cases and 8.2 million cancer-related deaths. Finding ways to diagnose and treat cancer in an early stage is of high importance since the mortality from this disease is highly influenced by its status at the time of diagnostic. One of the main directions in diagnostic pathology is to develop new methods that can provide accurate results at low costs. This project’s scope is related to the development of a label-free imaging device based on quantitative phase imaging (QPI) capable of analyzing cells within malignant or non-malignant tissues and discriminate between them by detecting slight refractive index variations of unstained tissues that are not otherwise possible with usual light microscopy techniques. The device to be developed will be composed of an interferometric set-up capable of providing quantitative information (optical pathlength/tissue density of the sample) about the tissue samples to be evaluated. This label-free method will provide an increased accuracy compared to currently employed methods by correlating the refractive index variation/distribution with the type of analyzed sample.

Molecular structures modification of medicines exposed to laser radiation, in view of their interaction with biological materials and bicompatible fabrics
PhD:
Ionut Relu Andrei
PhD Adviser
Prof. Dr. Mihail-Lucian Pascu
Finished:
2012

Cancer is one of the leading causes of death worldwide with approximately 14 million new cases and 8.2 million cancer-related deaths. Finding ways to diagnose and treat cancer in an early stage is of high importance since the mortality from this disease is highly influenced by its status at the time of diagnostic. One of the main directions in diagnostic pathology is to develop new methods that can provide accurate results at low costs. This project’s scope is related to the development of a label-free imaging device based on quantitative phase imaging (QPI) capable of analyzing cells within malignant or non-malignant tissues and discriminate between them by detecting slight refractive index variations of unstained tissues that are not otherwise possible with usual light microscopy techniques. The device to be developed will be composed of an interferometric set-up capable of providing quantitative information (optical pathlength/tissue density of the sample) about the tissue samples to be evaluated. This label-free method will provide an increased accuracy compared to currently employed methods by correlating the refractive index variation/distribution with the type of analyzed sample.

Molecular structures modification of medicines exposed to laser radiation, in view of their interaction with biological materials and bicompatible fabrics
PhD:
Adriana Smarandache
PhD Adviser
Prof. Dr. Mihail-Lucian Pascu
Finished:
2012

Cancer is one of the leading causes of death worldwide with approximately 14 million new cases and 8.2 million cancer-related deaths. Finding ways to diagnose and treat cancer in an early stage is of high importance since the mortality from this disease is highly influenced by its status at the time of diagnostic. One of the main directions in diagnostic pathology is to develop new methods that can provide accurate results at low costs. This project’s scope is related to the development of a label-free imaging device based on quantitative phase imaging (QPI) capable of analyzing cells within malignant or non-malignant tissues and discriminate between them by detecting slight refractive index variations of unstained tissues that are not otherwise possible with usual light microscopy techniques. The device to be developed will be composed of an interferometric set-up capable of providing quantitative information (optical pathlength/tissue density of the sample) about the tissue samples to be evaluated. This label-free method will provide an increased accuracy compared to currently employed methods by correlating the refractive index variation/distribution with the type of analyzed sample.

Molecular structures modification of medicines exposed to laser radiation, in view of their interaction with biological materials and bicompatible fabrics

Cancer is one of the leading causes of death worldwide with approximately 14 million new cases and 8.2 million cancer-related deaths. Finding ways to diagnose and treat cancer in an early stage is of high importance since the mortality from this disease is highly influenced by its status at the time of diagnostic. One of the main directions in diagnostic pathology is to develop new methods that can provide accurate results at low costs. This project’s scope is related to the development of a label-free imaging device based on quantitative phase imaging (QPI) capable of analyzing cells within malignant or non-malignant tissues and discriminate between them by detecting slight refractive index variations of unstained tissues that are not otherwise possible with usual light microscopy techniques. The device to be developed will be composed of an interferometric set-up capable of providing quantitative information (optical pathlength/tissue density of the sample) about the tissue samples to be evaluated. This label-free method will provide an increased accuracy compared to currently employed methods by correlating the refractive index variation/distribution with the type of analyzed sample.

Generation and identification of antimicrobial species from medicines exposed to laser radiation in view of fighting multiple drug resistance acquired by bacteria (ANTLAS)

One of the most important current drawbacks that have to be addressed in fighting infections with multiple drug resistant bacteria is the ineffectiveness of current antibiotics to destroy them and the lack of new antibiotic molecules and of new treatment schemes. At the same time, a fast and cheap approach for drug development is needed such as exposure of existing drugs to laser beams. Then, identification of new drugs must be made, which implies in most cases HPLC systems. A better solution is the high-performance thin layer chromatography (HPTLC), an offline method that is superior to other analytical techniques in terms of total costs and time for analysis. Development of a HPTLC single track scanner to identify new photoproducts is proposed in this project, for which low-intensity monochromatic light generated by picosecond lasers is used. The signal obtained from the HPTLC plates is analysed with a spectrograph equipped with a CCD camera for fluorescence spectra monitoring and a photomultiplier coupled to an oscilloscope for fluorescence lifetime evaluation. The overall objective of the proposal is to photo-generate antimicrobial species by exposing current drugs to UV laser beam and to characterize and identify the new species by performing qualitative and quantitative analysis using an improved HPTLC densitometry system. The results concerning the new species will be correlated with mass spectrometry measurements performed by LC-TOF/MS and the molecular structures of the antimicrobial compounds will be validated with Gaussian09 software.