Ketevan Chubinidze

Hemangioma is one of the most common types of infantile vascular benign tumor, possessing the potential for local tissue destruction, infection, bleeding, and pain. In this work, we propose a non-invasive, rapid, and inexpensive method of the visualization of subcutaneous hemangioma, based on the monodisperse spherical gold nanoparticles (GNPs) functionalized by the near-infrared fluorescent dye 3, 3′Diethylthiatricarbocyanineiodide. GNRs functionalized with the fluorescent dyes offer a number of properties that make them suitable for use in biological applications. In particular, in this typeof imaging, GNRs/NIR dye complex was introduced into the sample of hemangioma removed during the biopsy, and has been shown that this kind of modality serves as an effective contrast agent for the visualization of hemangioma located deeply under the epidermis. The obtained sample was examined and investigated using optical and confocal microscopes. The specimen was exposed to an external red laser light that can deeply penetrate the biological tissue. When a light beam reaches the GNR/NIR dye complex, the dye emits a NIR light which was then picked up by a CCD camera and was studied by a series of spectroscopic and microscopic techniques. Our results indicate that GNPs can promote the transport of GNPs/NIR dye nanocomposite across the skin and thus enable us to visualize the localization of the subcutaneous hemangioma formation, through fluorescence.

Compositions of liquid crystals (LCs) and nanoparticles form soft condensed systems via combining two extremely useful features of fluidity and space order with various unusual specific physical and biological properties of incorporate nanoparticles and nano-composites like ferromagnetic, antimicrobial, anti-inflammatory and anti-carcinogenic features. They can play an important role in several kinds of cancer therapy in the form of appropriate combinations of nano-fluids for magnetic hyperthermia and chemical-, photodynamic-, neutron capture-, hadron-, and conventional radio-therapy according to a novel concept and strategy being developed in Georgia in collaboration with colleagues from Germany, USA, Russia, Ukraine, Azerbaijan and other countries. They can also be used for developing of cancer treatment modalities with a controlled and prolonged release of active anticancer agents. That is why the toxicity of mixtures must be accurately assessed, when used for bio-sensing and as a main component of a smart delivery system of nano-drugs, containing a mixture of different magnetic and nonmagnetic nanoparticles providing the controlled hyper-thermal, chemical, radiation and photodynamic therapeutic impact. 324 various compositions of nine magnetic nanoparticles and their mixtures and nine liquid crystals controllable by temperature, optic radiation and pH and their mixtures were composed and their Curie temperatures and nematic-isotropic phase transition temperatures were determined. The Curie and nematic-isotropic phase transition temperatures of the most mixtures can be accurately matched to the so-called therapeutic interval of hyperthermia treatment interval of 41-45 C⁰ while their acute toxicity is only for 30-40 % higher compared to the toxicity of saline solution.

Approximately 1% of people suffer from epilepsy and 35% is drug-resistant form. Treatment strategies have been focused on flavonoids. Despite the positive pharmacological effects of Quercetin poor bioavailability limits its use. The loading of drugs to the nanoparticles facilitates their delivery and impact on the target locus. Magnetic nanoparticles drug delivery system could be controlled by magnetic field.The purpose of our research was to detect behavioral/morphological/electrophysiological effects of Quercetin-loaded magnetic nanoparticles (Q-MNP) and to investigate its influence on Kainic-Acid (KA)-induced epileptiform activity in the hippocampus. In ketamine-anesthetized rats Q-MNPs were injected in the tail vena. Unilateral magnetic field exposure to the brain was executed. Behavioral experiments were performed in open field/T-maze tests. To detect the Fe inserts in the cortical structures Perl's blue stain was used. The brain slices from two groups of animals with the right and the left-side magnetic field-exposure were prepared. In electrophysiological experiments electrodes were implanted bilaterally in to the hippocampus. Unilateral 5-fold KA administration were performed in the CA3-field for the generation of epileptiform activity. Q-MNP injection were carried out under condition of 60 min magnetic field exposure. Registration/analyses of obtained data were performed by Chart5.5 software. Software PRIZM was used for statistics. The experiments demonstrated that magnetic field, as well as MNP alone, does not change the behavior of animals. However Quercetin and/or Q-MNN improves learning ability of the rats. Morphological experiments revealed that the number of Fe inserts is significantly higher in the magnetic field-exposure site in comparison with the untreated contralateral site, suggesting that the exposure of magnetic field improves target-delivery of the Q-MNP to the brain. Electrophysiological experiment showed that Q-MNP as well as magnetic field alone did not change significantly the mean amplitude/frequency of neuronal activity, although preliminary administration of both factors statically reduced the frequency/amplitudes of KA-induced repetitive epileptiform discharges.

The development of a smart microencapsulation system programmed to actively respond to environmental stimuli is gaining increasing importance compared to the traditional forms of drug administration. In this study, we introduce two new concepts of the drug delivery system, based on the light and pH-sensitive liquid crystal (LC) microspheres. The proposed system represents an emulsion formed by the immiscibility between the LC microspheres and a water environment. The light controlled concept describes light activated drug delivery containers, based on spiropyran (SP) doped LC microspheres. Upon exposure to UV/violet light, the SP molecules entrapped inside the LC microspheres, interconvert from the hydrophobic, oil-soluble form, to the hydrophilic, water-soluble merocyanine (MR) one, which stimulates the translocation of the MR molecules across the LC/water barrier and results in their homogeneous distribution throughout in an aqueous environment.Various types of pH sensors used today are based on optical, surface, chemical and biological modifications. In this connection, we utilize an LC/water emulsion, but instead of SP molecules inside the LC microspheres were entrapped pH-sensitive fluorescent dye molecules that intelligently respond to the environmental pH change, resulting an immediate translocate across the LC/water interface. In the coming future, the use of light and pH controlled LC microspheres based drug delivery systems can find versatile application in areas such as cancer therapy and treatment.

Functionalized gold nanoparticles with controlled optical properties are the subject of intensive studies and biomedical applications, including genomics, biosensors, immunoassays, clinical chemistry and laser phototherapy of cancer cells, the targeted delivery of drugs, optical bioimaging and the monitoring of cells. In this work, we propose two nanocomposites consisting of gold nanoparticle (GNP) and fluorescent dye decorated proteins, which can serve as the contrast agents for the detection of diseases at the early stage of development, using the simple and inexpensive imagine methods. As the proteins targeted by GNPs and fluorescent dyes, we selected Calmodulin (CaM) and Prostate specific membrane antigen (PSMA). During the experiments, we have prepared and investigated CaM, PSMA and GNPs based nanocomposites and demonstrated that CaM and PSMA conjugated with fluorescent dye and GNPs can increase the fluorescence intensity upon the excitation of pumping laser source.This ability of controlled targeting and visualization of CaM/PSMA by fluorescence can be beneficially used in the tracking of CaM and PSMA mediates processes in biological tissues and cells, such as inflammation, metabolism, apoptosis, muscle contraction, intracellular movement, malignant cells growth, etc. 

Prostate cancer is the second cause of cancer death in men worldwide. The difficulty of imaging methods remains in identifying small volumes of prostate cancer in the prostate gland. Besides, they are partially invasive. The limitations of the imaging methods for prostate cancer detection motivated us to seek of alternative techniques. Here is demonstrated, that near infrared radiation (NIR) can be used successfully for the visualization of cancerous outgrowths in the isolated prostate.

Calmodulin (CaM) is a multifunctional Ca2+ binding protein. It functions as a central regulator of cellular metabolism in response to changes in cellular calcium levels by interacting with various targets. CaM has apotential therapeutic effect in cancer because of its suppressing action on cell proliferation and their capacity to revert the multi-drug resistance tendency of many tumor cells, including prostate cancer cells. Moreover, many effects of Ca2+ in cells are mediated by the binding of Ca2+ to CaM, which causes CaM to bind and activate target proteins. Consequently, the targeting and visualization of the regions in biological tissues, with overexpressed concentration of Ca2+/CaM complex could be a valid therapeutic approach in the detection and curing of cancer. The acquisition of images of biological matter by using fluorescent labels and nanomaterials is generally referred to as bioimaging and forms a large field of its own. Therefore, it could be of interest to use a nanocomposite consisting of CaM conjugated with fluorescent dye and Gold Nanoparticles (GNPs) as the potential optical indicator for the labeling of biological cells including cancer cells. In this study we investigate a CaM functionalized with fluorescent dye Nile blue (Nb) and GNPs, and show that a covalently linking CaM to the excited fluorescent dye and GNPs can stimulate a surface-plasmon-coupled emission, resulting a strong fluorescence enhancement. This effect successfully can be used for the targeting, labeling and visualization of CaM mediated processes, such as inflammation, metabolism, apoptosis, muscle contraction, intracellular movement, for the detection and treatment of cancer cells.

The development of a smart microencapsulation system programmed to actively respond to environmental stimuli is gaining increasing importance compared to the traditional forms of drug administration. Delivering drug locally, in the targeted placement and at the controlled portions, is a common way to decrease side effects due to the drug toxicity and, consequently, maximally reduce the undesirable side effects. The drug can either be adsorbed, dissolved, or dispersed throughout the nanoparticle complex or, alternatively, it can be covalently attached to the surface. Assorted types of remotely-triggerable drug delivery systems have been developed, which rely on applying an external stimulus to release the drug load. Ideally, such systems could determine the timing, duration, dosage, and even location of drug release, and could allow remote, noninvasive, repeatable, and reliable switching of therapeutic agent flux. Liquid crystalline materials are promising candidates for the sensing of biomaterials. LC ordering is highly sensitive to molecular-level physical and chemical interactions at the LC interface, which lead to changes in optical appearance. In this study, we introduce two new concepts of the drug delivery system, based on the light and pH sensitive liquid crystal (LC) micro spheres. The proposed system represents an emulsion formed by the immiscibility between the LC micro spheres and a water environment . LC based sensors are simple, label-free, and allow real-time reporting of various biological events such as the enzymatic hydrolysis of phospholipids, specific phospholipid–protein binding, and DNA hybridization. Light controlled concept describes light activated drug delivery containers, based on spiropyran doped LC micro spheres. Upon exposure to UV/violet light, the spiropyran molecules entrapped inside the LC micro spheres, interconvert from the hydrophobic, oil soluble form, to the hydrophilic, water soluble merocyanine one, which stimulates the translocation of the merocyanine molecules across the nematic liquid crystal-water barrier and results their homogeneous distribution throughout in an aqueous environment. As regards the second concept, we utilize the same LC/water micro emulsion, but instead of spiropyran molecules inside the LC micro spheres are entrapped pH sensitive fluorescent dye molecule that intelligently responds to the environmental pH change, resulting immediate translocation across the LC-water barrier and disseminates evenly throughout in an aqueous environment.

Cancer is a major public health problem in the worldwide. More than 11 million people are diagnosed with cancer every year. It is estimated that there will be 16 million new cases every year by 2020. Lung, colon, prostate, and breast cancers continue to be the most common causes of cancer death, accounting for almost half of the total cancer deaths among men and women. Prostate cancer (CaP) is the second most common cancer diagnosed in men globally. Survival of a cancer patient depends heavily on early detection and thus developing technologies applicable for sensitive and specific methods to detect cancer is an inevitable task for cancer researchers. Biomarkers have an important role in today’s diagnostics. A biomarker is a molecule that is up or down regulated depending on the physical state of the body. This make biomarkers interesting as deviations in biomarker levels that can reveal information about a patient’s health condition. It's known that prostate-specific membrane antigen (PSMA) is one of the most well established and highly specific prostate epithelial cell membrane antigen. PSMA is a type II transmembrane zinc metallopeptidase, belonging to the M28 peptidase family. It possesses hydrolyzing enzyme activities and is also known as FOLH1 (foliate hydrolase 1). In this investigation as the CaP biomarker we propose gold nanoparticles (GNPs) functionalized with PSMA and fluorescent dye Nile Blue (Nb). In our study, we have shown that the fluorescence enhancement strongly depends on: 1. Size, shape and concentration of GNPs. 2. Distances between GNRs, fluorescent dyes and PSMA. 3. Relative spectral positions between the plasmon absorptions of GNPs and the absorption and emission of the fluorescent dyes. As the result, we have developed a highly reliable and sensitive screening test diagnostic tools for the detection of prostate cancer in the early stage of its development. Furthermore, while GNPs have the potential to improve contrast with structural imaging modalities, functionalized GNPs could be useful in the field of photothermal therapy that uses light to destroy cancer cells by heat. Besides, a fluorescent dye Nb can be replaced by suitable near infrared dye, because the light irradiation in this region can penetrate deeper inside the tissues, increase the spatial resolution and cause less photodamage than UV/blue pert, as well as to avoid an overlapping of the signal with autofluorescence of biological samples.

Background & Aim: Despite the tremendous advances in the diagnosis, a prostate cancer remains as a second cause of cancer death in men worldwide. The drawback of the existent imaging method is that they cannot detect prostate carcinoma at the early stage of development. Besides, the methods are partially invasive. This circumstance resulted in searching of simple, noninvasive method for the detection of prostate cancer. In our earlier investigations, we have shown that near infrared radiation (NIR) penetrates biological tissues and particularly prostate tissue. In the present work we show that NIR can be used for the visualization of cancer outgrowth in the prostate in vitro. Methods: Experiments were carried out on the prostates derived from the radical prostatectomy. Infrared light emitting diodes (850-920 nm) were utilized for transillumination of prostates. Polarized NIR was captured by a charge coupled device (CCD) camera after passing the prostate. Prostate infrared images were visualized by a computer, coupled with CCD camera. Results: Experiments show that the optical density of cancerous and healthy prostate tissues differs from each other. Thereby, NIR penetrates healthy tissue readily than malignant one. Consequently, cancerous outgrowths are seemed as the dark spots on the bright background in a NIR transillumination images. Polarized IR light enhances transillumination images quality. Prostates were investigated with standard histo-morphological methods after NIR investigation. Results of infrared and histomorphological investigations, concerning the cancer location were compared. The comparisons show the coincidence of both findings in all cases. Developed software measures the ratios of brightness intensities of malignant and healthy tissues of prostate in the NIR transillumination images. Based on statistically reliable number of experimental data, software calculates so called confidence intervals for the data. This gives opportunity to determine malignancy of any new unknown prostate with 95% probability. Conclusions: Method of prostate cancer outgrowth NIR detection might be used in future for prostate cancer visualization and diagnosis in vivo.

Gold nanorods (GNRs) functionalized with fluorescent dyes offer a number of properties which make them suitable for use in biological applications, in particular in the diagnosis of diseases such as cancer. Molecular imaging techniques capable of good penetration depth in living tissue remain an important challenge in basic and clinical science, including modern biology and medicine. In the present work, we propose an in vitro demonstration of GNRs conjugated with near infrared (NIR) fluorescent dye complex, as an effective contrast agent for the visualization of prostate cancer cells. In this type of imaging, NIR dye/GNR complex is introduced into the subject, which is then exposed to an external source of invisible NIR light that can penetrate the biological tissue. When the light reaches the NIR dye / GNR complex, the dye emits a light which is then picked up by a detector or camera. Thereby we have experimentally demonstrated that: 1. NIR dye / GNR complex is prone to distribute across the location of the prostate cancer cells (suspected areas were predetermined by Histo-morphological investigations). 2. GNRs can dramatically enhance the NIR light intensity of nearby fluorescent dye because of the interactions between the dipole moments of the fluorescent dye and the surface plasmon field of the GNRs. Similarly to the work, we have found that the electric charge on the GNRs and the distance between GNRs and dye molecules have a significant effect on the fluorescence intensity, and this enhancement depends strongly upon the excitation wavelength of the pumping laser source. Enhancement in luminescence using fluorescent dye/ GNRs complex will lead to many applications for advancement in biomolecular labeling to produce novel optical contrast agents with high sensitivity and specificity. This method can be highly advantageous for the early stage cancer detection and visualization, because the reduced scattering and absorption of NIR irradiation (750 – 900 nm), which results in a deep penetration of light in the biological tissues.

In this study, we describe light activated fluorescent enhancement and optically controlled drug delivery, based on gold nanoparticles (GNPs) conjugated organic dye nanocomposite (a), and the spiropyran doped liquid crystal microspheres. First platform aims to visualize the cancer cells and the other one (b), to deliver the specific drug molecules in the targeted placement and at the controlled portions.(a) We present here GNPs formed and incorporated together with luminescent dye Nile blue (NbD) into a Poly (vinyl alcohol) film. The increase of luminescence of the NbD results from its interaction with GNPs surface plasmons. The electric charge on the GNPs and the distance between GNPs and luminescent dye molecules has a significant effect on the luminescence intensity, and this enhancement depends strongly upon the wavelength of the incident light. Enhancement in luminescence using GNPs /NbD complex will lead to many applications for advancement in biomolecular labeling to produce novel optical contrast agents with high sensitivity and specificity. These results may have great importance in chemotherapy, in cancer diagnosis. (b) In this work, we have demonstrated a novel, light controlled drug delivery system, based on spiropyran (SP) doped liquid crystal (LC) micro spheres. Experimental results have shown that upon exposure to UV / Violet light, the photochromic molecules located inside the LC spheres, experience an interconversion from the hydrophobic, oil soluble, non-polar SP state, to the hydrophilic, water soluble, highly polar merocyanine (MC) state. Light induced photoisomerization destabilize LC water interface, stimulates the translocation of MC molecules across the LC–water barrier and results their homogeneous distribution throughout in an aqueous nvironment. By combining above mentioned two results, it is possible to develop a new platform in which synergistically will be integrated an optically stimulated enhancement of fluorescence, to the photo stimulated drug delivery systems, that offer the possibilities of the controlled delivery and release of a wide variety of drugs into the body, at the suitable time and desired site, to simultaneously visualize and fight different kinds of diseases including cancer diseases. 

The use of light as a diagnostic tool for the detection and visualization of cancer cells at the early stage of development has grown considerably in recent years. Due to the distinguished optical properties, the combination gold nanoparticles (GNPs), with the fluorescent dyes are increasingly used as labeling tools in biological imaging. The interaction of luminescent molecules with plas- mons in metallic nanostructures and the physical phenomena related to nanoscale confinement of light have attracted the interest of physiccists over recent years. Fluorescence resonance en- ergy transfer (FRET) is a nonradiative process whereby an excited state donor transfers energy to a proximal ground state acceptor through long-range dipole−dipole interactions. Recently we have demonstrated that the emission of visible light from the polymer matrix doped with lumine- scence dye and GNPs can be enhanced with the use of surface plasmon coupling. GNPs can enhance the luminescence of nearby luminescent dye because the interactions between the dipole moments of the dye and the surface plasmon field of the GNPs. By matching the plasmon frequ- ency of GNPs to the frequency of pumping light source we have observed a luminescent enhan- cement of the nanopomposite consisting of GNPs coupled luminescent dye Nile blue 690 perchlorate. The increase of luminescence of the Nb 690 results from its interaction with GNPs surface plasmons. The wavelength of the excitation light source on the GNPs, the distance between GNPs and the dye molecules has a significant effect on the luminescence intensity. This tool for luminescence manipulation can be highly beneficial for optical, molecular sensing and imaging, for biotechnology applications, such as those needed in clinical diagnostics, for food quality control and drug delivery. Perhaps the most important application can be found as a revolutionary tool for ultrasensitive and noninvasive detection, visualization and diagnostics of the cancer cells at the early stage of its development.

In this abstract we describe silver and gold nanoparticles (NPs) incorporated in liquid crystal (LC) and polymer nanocomposites. Systems of NPs dispersed in LC and polymer matrices have attracted attention to the possible development of novel materials based on the controlled assembly of the particles. An attractive way to satisfy this conformational freedom requirement would be to hosting the NPs within flexible, tunable and organic medium as LCs and polymers. LC phases are found in DNA, proteins, lipids and polysaccharides. Our research is divided into three directions: 1. Light to heat conversions in the nanocomposites incorporated with silver and gold nanoparticles. This method relies on the optical properties of cholesteric LCs, confined into microdroplets dispersed in the medium, and combines the advantages of high spatial resolution and good temperature accuracy with fast readout. In this work, we propose the idea to use thermotropic cholesteric LC microdroplets for the non-intrusive visualization and measurement of the temperature distribution at the microscale. In particular, we focus on the visualization of the optical energy conversion to heat in metal NPs. Gold or silver NPs can efficiently release heat under optical excitation. When excited with a laser beam, the laser electric field strongly drives charge mobile carriers inside the NPs, and the energy gained by carriers turns into heat. Heat generation becomes especially strong in the regime of plasmon resonance. The NPs temperature may rise significantly and the heat can propagate to the surrounding medium. In our method, the temperature surrounding NPs can be estimated monitoring the color tuning

We present a novel method to calibrate the light to heat conversion in an aqueous fluid containing nanoparticles. Accurate control of light and heat is of dramatic importance in many fields of science and metal nanoparticles have acquired an increased importance as means to address heat in very small areas when irradiated with an intense light. The proposed method enables to measure the temperature in the environment surrounding nanoparticles, as a function of the exposure time to laser radiation, exploiting the properties of thermochromic cholesteric liquid crystals. This method overcomes the problems of miscibility of nanoparticles in liquid crystals, provides temperature reading at the microscale, since the cholesteric liquid crystal is confined in microdroplets, and it is sensitive to a temperature variation, 28°C-49°C, suitable for biological applications. In the figure below the colored trace left in the material after switching off the laser beam is shown.

Doctoral Thesis Referee

Master Theses Supervisor

Doctoral Thesis Supervisor/Co-supervisor

Scientific editor of monographs in foreign languages

Scientific editor of a monograph in Georgian

Editor-in-Chief of a peer-reviewed or professional journal / proceedings

Review of a scientific professional journal / proceedings

Member of the editorial board of a peer-reviewed scientific or professional journal / proceedings

Participation in a project / grant funded by an international organization

Participation in a project / grant funded from the state budget

Patent authorship

Membership of the Georgian National Academy of Science or Georgian Academy of Agricultural Sciences

Membership of an international professional organization

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National Award / Sectoral Award, Order, Medal, etc.

Honorary title

Monograph

Handbook

Research articles in high impact factor and local Scientific Journals

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