Nanotheranostics combining photodynamic and photothermal therapies (PDT and PTT) with other therapeutic modalities has been shown to result in synergistically enhanced cancer treatment with minimal adverse effects. This talk will present our results on synergistically enhanced cancer phototheranostics delivered with tumor microenvironment or external stimuli responsive multifunctional nanoplatforms. Three different nanoplatforms involve protein nanocrystals, nanoliposomes and silica-based hybrid nanoparticles. All the nanoplatforms incorporate contrast agents for optical/multimodal imaging and therapeutic agents allowing to combine PDT/PTT with chemo and chemodynamic therapies. An application of these imaging guided nanoplatforms allowed us to achieve a synergistic combination of photodynamic and/or photothermal therapies with chemo- and chemodynamic treatments, resulting in an efficient diagnostics and enhanced therapy of cancer cells in vitro and in animal model in vivo.
Photobiomodulation (PBM) of both oxidative stress and microglia metabolism associated with the activation of metabolic processes by 808 nm near-infrared light is carried out on microglia cells treated with β-amyloid. The light induces a metabolic shift from glycolysis to mitochondrial activity in pro-inflammatory microglia affected by Aβ. Thereby, the level of anti-inflammatory microglia increases. This process is accompanied by a decrease in pro-inflammatory cytokines and an activation of phagocytosis. Light exposure decreases the Aβ-induced activity of glucose-6-phosphate dehydrogenase, an enzyme that regulates the rate of the pentose phosphate pathway, which activates nicotinamide adenine dinucleotide phosphate oxidases to further produce ROS. During co-cultivation of neurons with microglia, light prevents the death of neurons, which is caused by ROS produced by Aβ-altered microglia. These original data clarify reasons for how PBM protects against neurodegeneration and support the use of light for therapeutic research in the treatment of Alzheimer's disease.
The results on design, synthesis, characterization and biomedical applications of core-thermoresponsive shell polymeric nanoparticles (CTS-PNPs) loaded with imaging and therapeutic agents will be presented. In CTS-PNPs, the polystyrene core (~30 nm) is coated with the shell of poly-N-isopropylacrylamide (PNIPAM) or co-polymer of NIPAM and acrylamide (AA). The shell “shrinks” in water at the temperatures higher than lower critical solution temperature, which can be tuned through co-polymerization of NIPAM with AA, and affects photophysics of the embedded fluorophores. This phenomenon has been employed by us in fluorescence imaging and photodynamic therapy of cancer using CTS-PNPs loaded with fluorescent dyes and photosensitizers.
KEYWORDS: Near infrared, Optical imaging, Animal model studies, Thermal modeling, Microscopy, Luminescence, In vivo imaging, In vitro testing, Imaging systems, Wound healing
This talk will present our recent results on photobiomodulation (PBM) in multiple cell types and models in vitro and in a mouse model in vivo. Different wavelengths (e.g., 650 nm, 808 nm, 1064 nm) and doses were employed and post-PBM changes in cells and animals were assessed in vitro, ex vivo and in vivo using fluorescence microscopy with fluorescent probes and label-free nonlinear optical imaging. The obtained imaging data, along with results of other assays, allowed for revealing PBM action and mechanisms. The talk will conclude with a discussion on application of red and NIR PBM to treat some diseases.
The talk will present our recent results on development of multifunctional biocompatible nanoplatforms for cancer theranostics. The three nanoplatforms targeting tumors include polymeric nanoparticles (PNPs), nanoliposomes and protein nanocrystals; they can be equipped with NIR luminescence, photoacoustic (PA) and computed tomography (CT) imaging contrasts, along with PDT/PTT and chemotherapy modalities, which can be selectively activated by tumor microenvironment (TME). The talk will also demonstrate application of PNPs for visible or NIR fluorescence labeling of the systemically injected mesenchymal stem cells, which manifest tumor tropism in metastatic cancer animal model, allowing for fluorescence imaging based detection of primary tumor and metastases.
KEYWORDS: In vivo imaging, In vitro testing, Alzheimer's disease, Microscopy, Luminescence, Light emitting diodes, Tissues, Near infrared, Visualization, Two photon imaging
A significant amount of recent studies reported use of photobiomodulation (PBM) to slow down the progression of Alzheimer’s disease. Less reports on improving the PBM therapeutic efficiency by optimizing light parameters. Our findings demonstrate that PBM effect in in vitro and in vivo AD models significantly depends on wavelength, dose and mode (continuous wave or pulsed) of irradiation. While the viability and anti-inflammatory activity of amyloid-β (Aβ) treated cultured neurons and microglia were improved after irradiation with 808 nm light, Aβ plagues accumulation and cerebral amyloid angiopathy in the AD mice brain were best attenuated after stimulation with 40 Hz pulsed 808 nm or spectrally broad visible light, which also improved spatial learning and memory abilities.Future research can involve simultaneous or sequential stimulation with visible and NIR pulsed light in optimize wavelengths, dose and frequencies to achieve efficient AD therapy.
The field of biophotonics embraces biomedical applications of light, particularly in diagnostics (e.g., optical bioimaging) and therapeutics (e.g., light induced therapy) of cancer and other diseases. At the same time, the biomedical field has been greatly advancing through a nanotechnology, which offers a platform for targeted drug delivery and multimodal medical imaging. Merging nanotechnology and biophotonics approaches resulted in a development of multiple nanoplatforms combining optical diagnostic and phototherapeutic capabilities; optical imaging guided nanotherapeutics is among the most intensively developing directions in nanobiotechnology.
In the last few years, we have been working on inorganic and organic nanomaterials for optical bioimaging and imaging guided phototherapy, along with a development of the advanced optical imaging modalities. This talk will present our recent results on development of heterogeneous nanoparticles that can be detected/ imaged/ differentiated in vitro and in vivo using near infrared (NIR) luminescence imaging. The proposed nanoplatforms comprise polymeric, lipid or protein nanoparticles along with rare earth ion doped fluoride nanocrystals, as well as their nanoblends with NIR fluorescent organic dyes and other functional small molecules, including molecular agents for chemo and photoinduced therapies of cancer. Spectral and temporal features of the photoluminescence from the developed nanoformulations allow for using them as imaging agents in hyperspectral, time-gated and luminescence lifetime imaging. While possessing the NIR imaging contrast and therapeutic functionality, the NIR emitting nanoformulations can also be garnished with other medical imaging modalities (e.g., computed tomography, CT, photoacoustic imaging, PAI), providing a single nanoagent for multiple imaging techniques and enabling the integration of cellular, tissue and whole body imaging. The talk will demonstrate examples of applications of nanoparticles as multimodal imaging guided therapeutic agents and conclude with a discussion on the challenges and opportunities in the domain of optically active nanoformulations for NIR imaging guided phototherapies of cancer and other diseases.
A term “theranostics” was coined more than two decades ago to tag an emerging paradigm of combining diagnostic and therapeutic capabilities for a modern personalized medicine. Biomedical applications of light also involve diagnostic (e.g., optical bioimaging) and therapeutic (e.g., light induced therapy) modalities, providing opportunity for the combined, theranostic approach. Optical transmission windows for biological tissues have been identified in near-infrared (NIR) region, allowing researchers to benefit from the reduced tissue scattering and autofluorescence in this spectral range and achieve optical imaging and imaging guided therapy of deeper tissues. NIR spectral region can also be beneficial for phototherapy (e.g., photodynamic therapy, PDT), allowing for deeper penetration of light to excite phototherapeutic agents. On the other hand, interaction of NIR light with tissues is known to produce beneficial therapeutic effects by itself: low level light therapy (a.k.a. photobiomodulation, PBM) with NIR light is reported to enhance wound healing, relieve pain, reduce inflammation and treat some pathological conditions.
Continuously increasing demand for biomedical diagnostics requires advanced imaging techniques. Time-gated imaging (TGI) of photoluminent bioprobes has a number of unique features, such as possibility to cut-off the excitation and autofluorescence and provide photoluminescence (PL) lifetime information in every pixel. However, as the other bioimaging techniques, TGI itself is not able to overcome the problem of high attenuation of light in the biological tissues. In recent years, imaging in the biological windows of optical transparency in near-infrared (NIR) and short wave infrared (SWIR) spectral ranges is being actively developed, providing an opportunity for the excitation and detection of PL signal in deeper biological tissues with higher resolution. In order to combine both advantages of NIR-SWIR imaging and TGI, we have built a time-gated imaging system performing in NIR-SWIR (900-1700nm) spectral range. Synchronizing setup has been developed in order to control delay between pulsed excitation source and NIR-SWIR camera. Through manipulation of the delay between the PL excitation source and imaging camera, stack of time-resolved PL images is obtained, which can be processed by the unmixing software. In summary, the developed technique allows us to distinguish and map regions of different NIR-SWIR PL lifetimes. An application of this method for spatial discrimination of rareearth ion doped nanoparticles emitting in NIR-SWIR range has been demonstrated.
Photodynamic therapy (PDT) employs light activation of tissue-localized photosensitizer in an oxygen-dependent process which initiates oxidative stress, inflammation, and cell death. Laser systems, which are mostly used in PDT as light sources can be costly and oversized. light-emitting diodes (LEDs) equipment has a high potential to simplify technical part of phototriggered therapies and to reduce its costs. We develop the LED-based system that includes the control and irradiation units. The system provides the same power density at any irradiation point. Among the advantages of the device is a possibility to change the irradiation area and tune the irradiation dose. PDT experiments with cancer cells in vitro treated with two different photosensitizers demonstrated a possibility to use the developed LED-based system as a low-cost light source in PDT.
Nanoscopic optical imaging has made prominent progress in recent years, which provides a powerful tool for modern biology science. Superresolution optical imaging allows for the observation of ultra-fine structures of cells, cellular dynamics and cellular functions at nanometer scale or even single molecular level, which greatly promotes the development of life science and many other fields. However, challenges still exist for super-resolution optical imaging for live cells and thick samples in terms of imaging depth, imaging speed as well as biomedical applications. This talk will review the recent progress in superresolution optical microscopy and present our recent work. By combining stimulation emission depletion (STED) microscopy and fluorescence lifetime imaging (FLIM), a STED-FLIM superresolution microscopy was developed to improve the spatial resolution of STED and also perform FLIM imaging at nanometer resolution. A new fluorescent probe with low STED laser power was designed for live cell mitochondria imaging. STED-FLIM imaging of microtubules labeled with ATTO647N inside HeLa cells and the mitosis process was obtained, which provides new insight into the cell structure and functions. In addition, coherent adaptive optical technique (COAT) has been implemented in a stimulated emission depletion microscope to circumvent the scattering and aberration effect for thick sample imaging. Finally, stochastic optical reconstruction microscopy (STORM) superresolution imaging of mitochondrial membrane in live HeLa cells was obtained by the implementation of new fluorescent probes, improved imaging system and optimized single molecule localization algorithm. This provided an important tool and strategy for studying dynamic events and complex functions in living cells.
Comparing to other optical imaging techniques, hyperspectral imaging (HSI) possesses a unique feature, being capable of not only obtaining a spatial information about a specimen, but also providing a spectral information in every image pixel. Being employed in biomedical applications, similarly to other optical bioimaging techniques, HSI struggles with limited light penetration depth, caused by high absorption and scattering of light by biological tissues. Overcoming the limitations of imaging in visible spectral range, optical bioimaging in near-infrared (NIR) and short wave infrared (SWIR) spectral ranges (~700 –1700 nm) has being actively advanced in recent years, as due to the strongly reduced tissue absorption and scattering, NIR-SWIR imaging systems can achieve deeper tissue imaging with higher resolution. With the aim to combine both the advantages of SWIR imaging and HSI, we have built a hyperspectral imaging system operating in NIR-SWIR spectral region (900 – 1700 nm). The constructed HSI system is based on a wavelengths scanning method, with a liquid crystal tunable filter (LCTF) as a dispersion element. The spectral unmixing software has been developed to map the regions of the specified spectral features. Finally, an application of the developed method towards spatial differentiation of rare-earth doped nanoparticles emitting in NIR-SWIR range has been demonstrated.
In this work we demonstrate the potential use of gold nanoparticles as contrast agents for the optical coherence tomography (OCT) imaging technique in dentistry. Here, a new in situ photothermal reduction procedure was developed, producing spherical gold nanoparticles inside dentinal layers and tubules. Gold ions were dispersed in the primer of commercially available dental bonding systems. After the application and permeation in dentin by the modified adhesive systems, the dental bonding materials were photopolymerized concurrently with the formation of gold nanoparticles. The gold nanoparticles were visualized by scanning electron microscopy (SEM). The SEM images show the presence of gold nanospheres in the hybrid layer and dentinal tubules. The diameter of the gold nanoparticles was determined to be in the range of 40 to 120 nm. Optical coherence tomography images were obtained in two- and three-dimensions. The distribution of nanoparticles was analyzed and the extended depth of nanosphere production was determined. The results show that the OCT technique, using in situ formed gold nanoparticles as contrast enhancers, can be used to visualize dentin structures in a non-invasive and non-destructive way.
Various problems arising during molecular imaging of different fluoroprobes and metabolites used in PDT can be
circumvented by focusing on multifunctional therapy agents. Thus an effective photo sensitizer coupled with other
useful roles to play in PDT treatment make nanoparticles as a good vehicle for different delivery assuming
multifunctional roles not only in PDT but also as therapeutic agents for targeted delivery. A new approach is the
involving use of 100 nm NPs as photo sensitizers and/or imaging agents. In our Lab., we employ two such NPs and are
ORMOSIL (organically Modified Silica) and PAA (Polyacrylamide) which are found to be biologically very safe
without disturbing the therapeutic value. The size of the nanoparticles determined by TEM and Dynamic Light
Scattering are ~30 nm. These NPs are taken up in conjunction with cyanine dye at near infra red as it has been reported
in literature that encapsulated NPs shows very low singlet oxygen production compared with the post-loaded NPs though
the reasons are not yet clear. Therefore, we investigated the idea of post-loading or adsorbing vis-a-vis encapsulation.
Laser tweezer trapping technology has been applied to monitor the bulk local solution viscosity during the sol-gel gelation process. The gelation rate is the same in depth ranges 2 - 20 microns from the bounding surface. Simultaneously with the laser tweezer study, a micro-viscosity kinetic measurement of the sol-gel process was performed using fluorescent anisotropy and quantum yield measurements. The differences between the bulk- and micro-viscosities obtained in the experiment reflect the intrinsic differences in solution environment sensed by the laser tweezer on the macro level and by other optical techniques within the probe microscopic environment.
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