Mihail Lucian Pascu

National Institute for Laser, Plasma and Radiation Physics · Department of Lasers

Breast cancer remains a global health challenge, prompting interest in the anticancer properties of other drugs, including chlorpromazine (CPZ). This study presents a novel approach in breast cancer treatment using laser irradiated CPZ. CPZ dissolved in distilled water, was exposed to 266 nm laser irradiation for varying durations, characterized by...

This paper reports results obtained using white light diffraction phase microscopy (wDPM) on captured images of breast and colon tissue samples, marking a contribution to the advancement in biomedical imaging. Unlike conventional brightfield microscopy, wDPM offers the capability to capture intricate details of biological specimens with enhanced cl...

"We report secure data transmission performed using chaotic lasers with different external cavity geometries and applying the chaotic masking method based on subcarrier and phase modulations of the chaotic optical carrier. Two semiconductor lasers with similar multimode emission spectra and self-optical feedback provided, respectively, by ring and...

Pharmaceuticals carried into space are subjected to different gravitational conditions. Hypergravity is encountered in the first stage, during spacecraft launching. The stability of medicines represents a critical element of space missions, especially long-duration ones. Therefore, stability studies should be envisaged before the implementation of...

The optical and spectral properties of foams and emulsions provide information about their micro-/nanostructures, chemical and time stability and molecular data of their components. Foams and emulsions are collections of different kinds of bubbles or drops with particular properties. A summary of various surfactant and emulsifier types is performed...

High-resolution spectrum analysis of the lasing emission of mm³-sized pendant droplets that contain aqueous solutions of the Rhodamine 6G (Rh6G) dye is reported. Pumping was performed with a 532 nm pulsed laser beam. The lasing emission demonstrates a complex spectral structure that contains mode-cluster peaks spaced 2 nm apart and a ripple structu...

A densitometry method based on steady-state and time-resolved fluorescence assessments for thioridazine and its photoproducts applied on HPTLC plates has been developed. The excitation source was a picosecond diode laser emitting at 375 nm. This method was used for the analysis of the photoproducts resulted from thioridazine irradiation with 266 nm...

Long-term space missions must be prepared to provide means to treat astronauts' illnesses that could occur at take-off, during flights or arriving on other planets. This could be achieved using multipurpose medicines. Phenothiazine derivatives, normally used to treat mental and emotional disorders, are photosensitive drugs and in solutions undergo...

Ciprofloxacin is one of the most prescribed antibiotics in treating bacterial infections, becoming an important pollutant of the wastewaters. Moreover, ciprofloxacin is hard to be destroyed by conventional water treatment processes; therefore, efficient treatments to destroy it are needed in water decontamination. This study offers insights into th...

The evolution of different antimicrobial drugs in terrestrial, microgravity and hypergravity conditions is presented within this review, in connection with their implementation during human space exploration. Drug stability is of utmost importance for applications in outer space. Instabilities may be radiation-induced or micro-/hypergravity produce...

Optics and optical spectroscopy are dynamic fields that are developing very fast nowadays, triggered by (i) the need to go deeper in the scientific approach to nature’s processes and phenomena, (ii) the evolution of applications in technological and industrial processes, art conservation, environment protection and cosmic space, and (iii) the somet...

Irgacure 2595 was exposed to 266 nm laser radiation to study its photodegradation rate in order to understand and improve hydrogel formation. The photodegradation process was monitored via fluorescence spectroscopy, UV-Vis and FTIR absorption spectroscopy. Comments and questions should be directed to the OSA Conference Papers staff (tel: +1 202.416...

Nowadays, antibiotic resistance has become increasingly common, triggering a global health crisis, immediately needing alternative, including repurposed drugs with potent bactericidal effects. We demonstrated that chlorpromazine aqueous solutions exposed to laser radiation exhibited visible activity against various microorganisms. The aim of this s...

Antibiotic resistance became an increasing risk for population health threatening our ability to fight infectious diseases. The objective of this study was to evaluate the activity of laser irradiated thioridazine (TZ) against clinically-relevant bacteria in view to fight antibiotic resistance. TZ in ultrapure water solutions was irradiated (1–240...

The worldwide infection with the new Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) demands urgently new potent treatment(s). In this study we predict, using molecular docking, the binding affinity of 15 phenothiazines (antihistaminic and antipsychotic drugs) when interacting with the main protease (Mpro) of SARS-CoV-2. Additionally,...

This paper presents a spectroscopic study of emulsions generated with a laser-assisted device. Fourier transform infrared (FTIR), Raman and UV–Vis–NIR reflectance spectra of emulsions, recorded before and after exposure to laser radiation were used to characterize the effect of laser irradiation. The paper also presents a comparison between the cal...

Fluorescence and lasing emission that are produced separately in time during excitation laser pulse for an mm-sized Rhodamine 6G dye-water droplet are reported. The droplet acts as a quasi-spherical closed optical resonator and due to multiple internal reflections, the resonant amplified emission is delayed with respect to fluorescence emission. Me...

Laser induced autofluorescence (LIAF) lifetime is useful to distinguish between normal laryngeal tissues and squamous cell carcinoma (SCC) based on variations of their biochemical composition and structure alterations. LIAF was collected from samples constituted by pairs of normal and malignant tissue, which were excised from three patients. Exclus...

Sclerotherapy continues to be the treatment of choice for varicose veins in the legs. However, isolated treatment using microfoam or lasers requires a high number of sessions to eliminate them. In 2013, we published results about the efficacy and safety 3 years after the combined treatment with microfoam injections and subsequent application of Nd:...

Emulsification methods are of interest for numerous fields and those that generate nanoemulsions are, particularly, of great interest for medical applications. This paper presents a new laser-assisted device that may generate pharmaceutical emulsions. One of its advantages is that allows the use of small quantities of solutions, as low as a few hun...

Aqueous chlorpromazine solutions exposed to 266 nm generated as fourth harmonic of Nd:YAG pulsed laser along time intervals from 1 min to 240 min were investigated for their antimicrobial activity against planktonic and adherent Gram-positive bacterial strains. Qualitative and quantitative assays based on microbiological methods and flow cytometry...

Super-resolution reconstructs a high-resolution image from one or more low-resolution recorded images. It uses a variety of hardware techniques, such as sensor raster scanning, or software techniques, such as interpolation, iterative backprojection, and the regularized methods, and it is useful in a variety of applications, such as video surveillan...

Time-stability studies of two non-antibiotics, chlorpromazine and thioridazine, which possess antimicrobial activity after their exposure to UV pulsed laser beams, are reported. The role of stability testing is to provide information about how the quality of such a drug varies over time, in view of further applications. The dynamics of identified p...

This is a review about exposure of drugs solutions to uncoherent and laser radiation in order to induce changes in drugs’ molecules and to generate photoproducts that alone or in mixtures have photo-enhanced activity. This could be a way to combat the failure of treatments when multidrug resistance is acquired by microorganisms or tumors. The struc...

Results for the interaction of a 532 nm pulsed laser beam with individual pendant rhodamine 6G dye droplets of a large-size parameter, x ≈ 7300 , are reported. By varying dye concentration and pumping energy, typical fluorescence bands detected in such cases are obtained, along with a narrow, instantly, or gradually blueshifted band assigned to the...

An ex vivo case series aimed at identification of normal laryngeal tissue from laryngeal epidermoid squamous keratinized carcinoma by measuring laser-induced autofluorescence (LIAF) and Fourier transform infrared–attenuated total reflectance (FTIR-ATR) spectra is presented. The case series results were obtained for paired samples extracted from thr...

Background: The use of laser methods to irradiate currently used drugs in order to obtain photo-products with antimicrobial and anti-tumour activity constitutes a new approach in fighting antimicrobial resistance acquired by bacteria and tumours. Methods: The interaction of UV laser radiation with phenothiazine derivatives, such as chlorpromazine,...

Covalently functionalized single wall carbon nanotubes (SWCNT) with the photosensitizer verteporfin (VP) were synthesized and studied. Photophysical properties of the obtained compounds like optical absorption, laser-induced fluorescence and generated singlet oxygen were investigated. In order to highlight the features of the conjugated compound, i...

A study of photosensitized cleavage of different olefins as potential linkers for drug carrier complexes is reported. The role of singlet oxygen and the kinetic rates for light induced reactions were estimated by time-resolved measurements of singlet oxygen phosphorescence (at 1270 nm) obtained via 532 nm pulse laser excitation of a photosensitizer...

This paper presents data about photophysics of two novel thio-hydantoins that exhibit promising pharmaceutical properties in multidrug resistance control. Time stability studies are necessary to establish the proper use of these compounds in different applications. As for their administration as drugs, it is imperative to know their shelf life, as...

The chapter presents a synthesis of results obtained on resonant interaction of laser radiation with medicines, in bulk, such as: cytostatics (methotrexate, 5-fluorouracil), phenothiazines (thioridazine, promethazine), quinazoline derivative (BG 1188) and hydantoin derivative (SZ-2). The effect of laser radiation on the studied samples is evaluated...

In this chapter, are introduced data about the laser induced fluorescence and Raman spectra obtained from microvolumetric (some microliters) droplets when they are exposed to laser radiation of suitable characteristics in terms of wavelength, power, focusing conditions. A comparison is made with the same spectra obtained for the same solutions and...

Resonant interaction of a laser beam with a single droplet takes place if the beam is absorbed in the droplet. Here are shown results regarding the resonant interactions of a pulsed laser beam with microliter droplets in pendant position that contain solutions of a laser dye-rhodamine 6G, phenothiazines (chlorpromazine, promazine), hydantoin deriva...

This chapter presents results regarding the production of emulsions and foams and their interaction with laser beams. Foams and emulsions are considered mainly as collections of bubbles, or drops of different kind with particular properties, respectively. Here, emulsions of oily vitamin A and water in which various surfactants were introduced are d...

The development of new medicines and alternatives to existing antimicrobial agents represents a high priority in treating infections caused by multi-drug resistant bacteria. This is reported mainly, as multiple resistance acquired by bacteria at treatment with antibiotics. The use of laser radiation to photo-generate new compounds from known medici...

The article reports, in the general context of developing techniques to generate microjets, nanojets and even individual nanodroplets, a new method to obtain such formations by interaction of a single laser pulse at 532 nm with an individual/single mother droplet in pendant position in open air. The beam energy per pulse is varied between 0.25 and...

Studies on the emission spectra of microdroplets containing Rh6G solutions in water doped with TiO2 nanoparticles are reported. The excitation is made by the second harmonic of a pulsed Nd:YAG laser at 532 nm, pulse duration at half maximum 6 ns and energy varied between 6–10 mJ. The laser induced emission spectra are analyzed function of TiO2 conc...

This research was focused on the effects of DMSO-water ratio on the photophysics of the sensitizer Zn phthalocyanine (ZnPc) and on the photogenerated singlet oxygen. To reach this objective optical absorption, flash photolysis and time-resolved phosphorescence were used. Potential dye accumulation at the surface of the sample was studied by surface...

The singlet oxygen quenching rate constants were measured for three model proteins, bovine serum albumin, β-lactoglobulin and lysozyme. The results were analyzed by comparing them with the corresponding singlet oxygen quenching rate constants for a series of tripeptides with the basic formula GlyAAGly where the central amino acid (AA) was the oxidi...

The study of photocleavage of different substrates as potential linkers for drug carrier compounds is reported. The role of singlet oxygen and the kinetic rates implied in the photoreactions were determined. The study envisaged the use of two olefins: 7-(4-chlorophenyl)hept-6-enoic acid and 7-(ferrocene)hept-6-enoic acid as potential linkers for th...

This study presents the optical properties of a new hydantoin derivative, generically called SZ-2. A stability assay using UV/VIS/NIR spectra was performed up to 250 days, as well as FTIR spectroscopic characterization. Liquid samples of SZ-2 in DMSO in bulk were exposed to 355 nm pulsed laser radiation emitted by a Nd:YAG laser for different time...

This paper deals with the rapid molecular changes induced by laser radiation on two novel hydantoin derivatives, generically named SZ-2 and SZ-7, having promising pharmaceutical properties as Szymanska et al. in 2002 and Subtelna et al. in 2010 have reported. Hydantoins solutions with concentration of 10-3 M in dimethyl sulfoxide were exposed both...

Multiple drug resistance requires a flexible approach to find medicines able to overcome it. One method could be the exposure of existing medicines to ultraviolet laser beams to generate photoproducts that are efficient against bacteria and/or malignant tumors. This can be done in droplets or bulk volumes. In the present work are reported results a...

As a phenothiazine derivative, Promethazine may undergo structural modifications when it is exposed to light. This process consists in the degradation of the initial compound and in the generation of new photoproducts with possible anti-infectious qualities. Stability studies are necessary in order to establish the proper use of drug solutions in d...

This study presents results about UV laser beam interaction with Vancomycin (VCM) solutions in ultrapure water performed on bulk samples (5 mL). Photoproducts and molecular fragments resulting from the parent VCM and generated by exposure to 266 nm are evidenced by UV-vis absorption and FTIR spectroscopy and liquid chromatography electro spray ioni...

Phenothiazine derivatives are non-antibiotics with antimicrobial, fungistatic and fungicidal effects. We exposed to a high energy UV laser beam phenothiazines solutions in water at 20mg/mL concentration to increase antibacterial activity of resulting mixtures. Compared to previous results obtained on bacteria, more research is needed about UV laser...

The study reports an investigation of the photoproducts obtained by exposure of chlorpromazine hydrochloride in ultrapure water (concentration 2 mg/mL) to a 266-nm laser beam obtained by fourth harmonic generation from a Nd:YAG laser (6-ns full time width at half maximum, 10-Hz pulse repetition rate). The photoproducts were analyzed by steady-state...

In this paper, laser beam resonant interaction with pendant microdroplets that are seeded with a laser dye (Rhodamine 6G (Rh6G)) water solution or oily Vitamin A emulsion with Rhodamine 6G solution in water is investigated through fluorescence spectra analysis. The excitation is made with the second harmonic generated beam emitted by a pulsed Nd:YA...

We report the use of TLC image analysis software, JustTLC, for identification and quantitative evaluation of the photoproducts generated by the irradiation of Chlorpromazine water solutions with a 266 nm laser beam. The percent concentrations resulting for photoproducts from TLC analysis were compared with the relative concentrations of those ident...

We report photophysics studies of some compounds of interest in drug targeted delivery and conjugated single walled carbon nanotubes with a photosensitizing agent. Supramolecular entities porphyrin-carbon nanotubes have been synthesized by covalent functionalization and have been analyzed in terms of photostability, microfluidics (surface tension a...

Laser induced fluorescence and amplification of fluorescence by laser pumped Rhodamine-6G solutions - having selected volumes - in water have been investigated. The results are comparatively presented for bulk and pendant droplets with emphasis on the amplification obtained in the second case. In the case of pendant droplets two different collectio...

The Polidocanol microfoam sclerotherapy is a potential treatment of venous disease. Recently, four years conducted clinical trials confirm that the Polidocanol microfoam injections assisted by pulsed Nd:YAG laser therapy improves the cure's efficacy. Started from these, laser beams interaction of liquid as well as microfoam Polidocanol was investig...

Foam sclerotherapy is a widely used method to treat varicose veins disease. It is easy to use and apply, affordable, and has high efficiency that depends on foam stability upon injection. Since sclerotherapy is usually applied in a medical doctor's office, one of the most employed methods to generate foam is based on the Tessari technique which use...

Different emulsification techniques lead to emulsions with different targeted properties specific to their intended use. In this study, emulsions are generated using several emulsification techniques. They are compared as regards the component droplet size distribution and their stability in time. A particular technique based on the “Tessari” (know...

We have recently reported the set-up of an experimental system for the laser-induced photochemical modification of bioactive substances, where two ecdysteroids, 20-hydroxyecdysone (20E) and its diacetonide derivative served as probes. As a direct continuation of our previous work, three new compounds together with five other ecdysteroid derivatives...

Phenothiazine exposed to white light or UV radiation undergoes a variety of reactions that result in the degradation of the parental compound and the formation of new species. Chlorpromazine exposed to the 266 nm laser beam of given energy levels yielded species derived from it, whose number increased with the exposure duration. At distinct time in...

Chlorpromazine (CPZ) was exposed to a 266nm laser beam for different periods of time ranging from minutes to 24 h. At intervals, the products from irradiation were evaluated by thin-layer chromatography (TLC) and evaluated for their activity against mycobacteria of human interest (Mycobacterium tuberculosis, M. avium, M. intracellulare and their co...

To assess the efficacy and safety of a new method of clearing varicose veins in the long term. It consists of applying the long-pulsed Nd:YAG laser following the injection of polidocanol microfoam, in two consecutive sessions, treating both legs in full in each session. Randomized, Polidocanol-controlled, blind evaluation clinical trial comparing t...

Synchronization characteristics of two bidirectionally coupled semiconductor lasers, one operating in a chaotic regime with low-frequency fluctuations and the other with free laser beam emission, were experimentally investigated. The chaotic synchronization regimes and optical spectral behavior of the coupled system were analyzed with respect to th...

Photophysical properties of phthalocyanines are important in photodynamic therapy, where these compounds are proposed as photosensitizing agents. We report here some significant solvent effects on the photophysical properties of Zn phthalocyanine (ZnPc) observed in binary solvent mixture dimethyl sulfoxide/water at several ratios of cosolvents. The...

A short description of the photodynamic therapy as an alternative cancer treatment procedure is made, highlighting the role of the photosensitiser and of the basic molecular processes resulting in active species. The synthesis path of metallated phthalocyanine photosensitizers used in this paper are presented and analyzed, considering the conventio...

Phenothiazines when exposed to white light or to UV radiation undergo a variety of reactions that result in degradation of parental compound and formation of new species. This process is slow and may be sped up with exposure to high energy light such as that produced by a laser. Varying concentrations of Chlorpromazine Hydrochloride (CPZ) (2-20 mg/...

Varying concentrations of Chlorpromazine Hydrochloride (CPZ) were exposed to a 266 nm laser beam for varying periods of time ranging from 4 to 24 hrs and the products of irradiation were evaluated for activity against a panel of bacteria that consisted of representatives of Gram-positives and Gram-negatives that expressed different degrees of efflu...

In the present work two semiconductor lasers (SL) were optically coupled into a master—slave synchronization scheme. The master system was a SL operated under external optical feedback conditions in the low-frequency fluctuations (LFF) chaotic regime, while the slave system was a solitary laser with free emission. Chaotic synchronization regimes an...

Phenothiazine derivatives are sensitive to light, especially to UV radiation. Chlorpromazine (CPZ) and Promazine (PZ) solutions in ultrapure water were exposed to 266 nm laser radiation in order to modify their structure and to obtain new species active against multidrug resistant bacteria. Modifications of the UV-Vis absorption spectra of the solu...

The extensive use of pharmaceuticals became a worldwide environmental issue. Most of these compounds are not completely removed in wastewater treatment plants and, as a result, they are found in surface and ground water. In this report the behavior of two drugs, Thioridazine and BG1188 were investigated after their exposure in aqueous solutions to...

Treatment of micro-veins of less than 1.5 mm with laser and with chemical sclerosis is technically challenging because of their difficulty to remedy. Laser treatment is even more difficult when dark phototypes are involved.Three groups of 30 patients each, skin type IV, and vessels measuring less than 1.5 mm in diameter, were enrolled for two treat...

Laser spectroscopy techniques are modern and competitive methods for elemental analysis. Laser induced breakdown spectroscopy (LIBS), due to its advantages as minimally invasive method that provides real time monitoring and selectivity, is a suitable tool to analyze sample composition. Based on the known emission spectra of heavy metals such as Pb,...

Literature reports show numerous studies concerning the occurrence, evolution, detection and removal of, generically, pharmaceutical pollutants in/from environment. The current report is focused on the Phenothiazines class, in particular on Thioridazine (Thr). We discuss the time evolution of the absorption spectra of Thioridazine HCl solutions in...