Academic literature on the topic 'Dye-loaded polymeric nanoparticles'

In the era of climate changes, harmful dinoflagellate outbreaks that produce potent algal toxins, odor, and water discoloration in aquatic environments have been increasingly reported. Thus, various treatments have been attempted for the mitigation and management of harmful blooms. Here, we report engineered nanoparticles that consist of two different types of rylene derivatives encapsulated in polymeric micelles. In addition, to avoid dissociation of the aggregate, the core of micelle was stabilized via semi-interpenetrating network (sIPN) formation. On two types of the marine red-tide dinoflagellates, Akashiwo sanguinea and Alexandrium pacificum, the nanoparticle uptake followed by fluorescence labeling and photothermal effect was conducted. Firstly, fluorescence microscopy enabled imaging of the dinoflagellates with the ultraviolet chromophore, Lumogen Violet. Lastly, near-infrared (NIR) laser irradiation was exposed on the Lumogen IR788 nanoparticle-treated Ak. Sanguinea. The irradiation resulted in reduced cell survival due to the photothermal effect in microalgae. The results suggested that the nanoparticle, IR788-sIPN, can be applied for potential red-tide algal elimination.

Polymeric nanoparticles (NPs) find many uses in nanomedicine, from drug delivery to imaging. In this regard, poly (lactic-co-glycolic acid) (PLGA) and polyethylene glycol (PEG) particles are the most widely applied types of nano-systems due to their biocompatibility and biodegradability. Here we developed novel fluorinated polymeric NPs as vectors for multi-modal nanoprobes. This approach involved modifying polymeric NPs with trifluoroacetamide (TFA) and loading them with a near-infrared (NIR) dye for different imaging modalities, such as magnetic resonance imaging (MRI) and optical imaging. The PLGA-PEG-TFA NPs generated were characterized in vitro using the C28/I2 human chondrocyte cell line and in vivo in a mouse model of osteoarthritis (OA). The NPs were well absorbed, as confirmed by confocal microscopy, and were non-toxic to cells. To test the NPs as a drug delivery system for contrast agents of OA, the nanomaterial was administered via the intra-articular (IA) administration method. The dye-loaded NPs were injected in the knee joint and then visualized and tracked in vivo by fluorine-19 nuclear magnetic resonance and fluorescence imaging. Here, we describe the development of novel intrinsically fluorinated polymeric NPs modality that can be used in various molecular imaging techniques to visualize and track OA treatments and their potential use in clinical trials.

TiO2-loaded poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-coHFP) membranes were produced by supercritical CO2-assisted phase inversion. Three different TiO2 loadings were tested: 10, 20, and 30 wt% with respect to the polymer. Increasing the TiO2 amount from 10 wt% to 20 wt% in the starting solution, the transition from leafy-like to leafy-cellular morphology was observed in the section of the membrane. When 30 wt% TiO2 was used, the entire membrane section showed agglomerates of TiO2 nanoparticles. These polymeric membranes were tested to remove Sudan Blue II (SB) dye from aqueous solutions. The adsorption/photocatalytic processes revealed that membrane morphology and TiO2 cluster size were the parameters that mainly affected the dye removal efficiency. Moreover, after five cycles of exposure of these membranes to UV light, SB removal was higher than 85%.

Biomedical applications of nanoparticles (NPs) have reached an increasing development in recent years. Recently, we demonstrated that newly synthesized poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) are possible antitumor agents due to their cytotoxicity for cancer cells. Indocyanine green (ICG), an amphiphilic tricarbocyanine fluorescent dye, is widely used for the detection of tumoral extension in different organs during clinical surgery. Moreover, this fluorescent agent is unstable and it has a rapid clearance in physiological conditions in vivo. In this study, ICG was charged in PECA-NPs to improve its aqueous stability and make easier its use for the identification of tumor cells. Microscopic and ultrastructural aspects concerning the related in vitro interactions between ICG-loaded NPs and tumor cell culture were investigated. Obtained results showed an effective stabilization of ICG; furthermore, color inclusions inside the cells treated with ICG-loaded NPs demonstrated the internalization of NPs with associated ICG. Transmission electron microscopy (TEM) analysis demonstrated the cytoplasmic presence of coated vesicles (Ø ≤ 100 nm), hypothesizing their involvement in the mechanism of endocytosis. Therefore, ICG-loaded NPs could be proposed as agents for tumor diagnosis, hypothesizing also in the future a specific therapeutic treatment.

Background: In the past decade, researchers have focused on developing new biomaterials for cancer therapy that combine imaging and therapeutic agents. In our study, we use a new biocompatible and biodegradable polymer, termed poly(glycerol malate co-dodecanedioate) (PGMD), for the synthesis of nanoparticles (NPs) and loading of near-infrared (NIR) dyes. IR820 was chosen for the purpose of imaging and hyperthermia (HT). HT is currently used in clinical trials for cancer therapy in combination with radiotherapy and chemotherapy. One of the potential problems of HT is that it can up-regulate hypoxia-inducible factor-1 (HIF-1) expression and enhance vascular endothelial growth factor (VEGF) secretion. Results: We explored cellular response after rapid, short-term and low thermal dose laser-IR820-PGMD NPs (laser/NPs) induced-heating, and compared it to slow, long-term and high thermal dose heating by a cell incubator. The expression levels of the reactive oxygen species (ROS), HIF-1 and VEGF following the two different modes of heating. The cytotoxicity of NPs after laser/NP HT resulted in higher cell killing compared to incubator HT. The ROS level was highly elevated under incubator HT, but remained at the baseline level under the laser/NP HT. Our results show that elevated ROS expression inside the cells could result in the promotion of HIF-1 expression after incubator induced-HT. The VEGF secretion was also significantly enhanced compared to laser/NP HT, possibly due to the promotion of HIF-1. In vitro cell imaging and in vivo healthy mice imaging showed that IR820-PGMD NPs can be used for optical imaging. Conclusion: IR820-PGMD NPs were developed and used for both imaging and therapy purposes. Rapid and short-term laser/NP HT, with a low thermal dose, does not up-regulate HIF-1 and VEGF expression, whereas slow and long term incubator HT, with a high thermal dose, enhances the expression of both transcription factors.

Abstract Nanoparticles based drug delivery systems have provided a befitted solution for the poor pharmacokinetic properties and systemic toxicity caused by the chemo drugs because of their ability to improve bioavailability of the drugs at the desired site and thereby decreasing extracellular toxicity. The present work investigates the single or dual chemo drugs loaded PLA-based biodegradable polymeric nanoparticles for improved anti-tumor efficacy as compared to free drug formulations. For the study, an amphiphilic block copolymer; mPEG PLA has been synthesized and characterized using Gel permeation chromatography (GPC) for its molecular weight and poly dispersity index as well as with Nuclear magnetic resonance (NMR) and Fourier-transform Infrared (FT-IR) spectroscopies. Thereafter, two different chemo drugs Pirarubicin (PIRA, THP analogue of Doxorubicin) and Gemcitabine (GEM) have been chemically conjugated individually to mPEG PLA block copolymer via a linker molecule, Levulinic acid to give an acid labile polymer-drug conjugate and the % drug conjugation efficiency has been calculated using High performance liquid chromatography (HPLC). The synthesized polymer-drug conjugates have been employed to prepare PIRA/GEM single or dual-loaded nanoparticles via nanoprecipitation technique and the physiochemical properties including size, zeta potential, and stability were analyzed using Dynamic Light Scattering (DLS) and High-resolution transmission electron microscopy (HR-TEM). To carry out toxicity assessment of the mPEG PLA nanoparticles, both cytocompatibility and hemocompatibility were checked using MTT assay and Hemolysis assay respectively. Moreover, the cellular internalization studies of dye-loaded mPEG PLA nanoparticles were done using Confocal microscopy on SUM-149, breast cancer cells. Besides, the drug release kinetic studies of the free PIRA/GEM from the PIRA/GEM single or dual-loaded nanoparticles were carried out in different pH environments; pH 7.4 and pH 5.0. The in-vitro cell proliferation inhibition studies of PIRA/GEM or dual-loaded nanoparticles were carried out on different human and murine breast cancer cell lines including MCF-7, MDA-MB-468, SUM 149, MDA-MB-231 and 4T1 and half-maximal inhibitory concentrations (IC50 values) were compared to that of respective free drug formulations. The overall results suggested that the prepared sub-nano sized PIRA/GEM single or dual-loaded particles are highly stable, uniformly spherical in size and biocompatible in nature. They were found to possess high cellular uptake, sustained drug release rate and synergistic efficacy and potential against both human and murine breast cancer cells in-vitro conditions. Citation Format: Priya Gupta. Development of poly lactic acid based biodegradable nanoparticles for co-delivery of pirarubicin and gemcitabine for synergistic anti-tumor efficacy [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A031.

La quantification de biomarqueurs spécifiques est un outil de diagnostic important. Les tests immunologiques standards tels que ELISA nécessitent de nombreuses étapes de lavage et une amplification du signal, en particulier à faible concentration. D'autre part, le transfert d'énergie résonant de type Förster (FRET) a été utilisé pour concevoir des tests biologiques homogènes en une seule étape qui ne nécessitent aucune étape de lavage, où le biomarqueur permet la formation d'un complexe "sandwich" impliquant des anticorps marqués par le donneur et d'autres marqués par l'accepteur. Le FRET du donneur vers l'accepteur fournit alors une signature optique de la formation du complexe, et donc du biomarqueur d'intérêt. Cependant, le FRET, qui est très sensible à la distance donneur-accepteur, ne se produit à un taux significatif que lorsque la distance donneur-accepteur est inférieure à 10 nm; la grande taille de nombreux complexes biologiques limite l'efficacité du transfert d'énergie, empêchant une détection sensible. Je propose ici une nouvelle modalité de transfert d'énergie qui utilise des microcavités optiques en solution. Ensuite, je décris un schéma de biodétection pour détecter un oligonucléotide biomarqueur de cancer en solution.À cette fin, j'ai conçu des structures de microcavité dans lesquelles des nanocristaux fluorescents sont placées à l'intérieur de microsphères diélectriques pour permettre un couplage fort de leur émission de fluorescence avec les modes de résonance de la cavité, appelés modes de galerie (WGM). J'ai étudié les propriétés structurelles et optiques de ces microcavités optiques. J'ai également caractérisé le transfert d'énergie entre ces modes et des nanoparticules acceptrices chargées de colorants présentes dans le champ évanescent, à quelques dizaines de nm au-dessus de la surface des microsphères. J’ai développé un modèle analytique pour caractériser les mécanismes de transfert d'énergie médié par les WGM (WGET). De plus, une comparaison entre WGET et FRET a révélé la supériorité du WGET dans le contexte de la construction de capteurs en termes de sensibilité et de portée de détection. Dans la dernière partie de la thèse, j’ai développé une stratégie pour fonctionnaliser ces microcavités optiques et leur permettre d'interagir avec des analytes cibles tels que l'ADN, l'ARN et les protéines avec une bonne spécificité. Cette stratégie a ensuite été adaptée pour fixer des sondes de capture d'ADN sur les microcavités activées par WGM. En utilisant les microsphères fixées à l'ADN comme donneur optique en combinaison avec des nanoparticules de colorants fonctionnalisées par un ADN complémentaire comme accepteurs optiques, un test de biodétection a été démontré avec succès pour détecter en solution un biomarqueur de cancer appelé survivine. Ce test a démontré une bonne sensibilité envers la cible, et s'est également avéré très spécifique. Le schéma de détection a été démontré dans un microscope confocal, au niveau de microsphères individuelles, puis transposé avec succès dans un instrument beaucoup plus simple tel qu'un spectrofluoromètre qui mesure la fluorescence de l'ensemble de la solution; la signature de la formation d'un complexe sandwich a été détectée efficacement.En conclusion, j'ai démontré que le transfert d'énergie assisté par microcavité présente plusieurs avantages par rapport aux tests FRET ordinaires. Un véritable test de biodétection basé sur le principe du WGET a également été conçu avec succès pour détecter des biomarqueurs du cancer avec une sensibilité et une spécificité élevées. Cette étude ouvre donc de nombreuses possibilités pour concevoir des tests plus performants et plus précis pour détecter diverses entités biologiques
Quantification of specific biomarkers is an important diagnostic tool. Standard immunoassays such as ELISA require extensive washing steps and signal amplification, in particular when the biomarker of interest is only present at very low concentrations. On the other hand, non-radiative Förster resonance energy transfer (FRET) has been used to design one-step homogenous bioassays which do not require any washing steps, where the biomarker enables the formation of a sandwich complex involving donor-labeled and acceptor-labeled antibodies. FRET from the donor to the acceptor then provides an optical signature of the complex formation, hence of the biomarker of interest. However, FRET which is highly sensitive to the donor-acceptor distance, only occurs in a significant rate when the distance between the donor and acceptor is less than 10 nanometers; thus the large size of many biological complexes limits the efficiency of energy transfer, preventing sensitive detection. Here I propose a novel energy transfer modality that uses solution-phase optical microcavities to enhance energy transfer. Following that, I describe a bio-sensing scheme designed to detect a cancer biomarker DNA in solution.To this aim, I have designed microcavity structures in which fluorescent colloidal quantum dots are located inside dielectric polymer microspheres to enable strong coupling of their fluorescence emission with the cavity resonance modes or whispering gallery modes (WGMs) of the microspheres. A detailed study was carried out to comprehend the structural and optical properties of these optical microcavities. I also characterized the energy transfer between these modes and acceptor dye-loaded nanoparticles present in the evanescent field, within a few tens of nanometers above the microsphere surface. An analytical model was constructed to provide insights into the WGM mediated energy transfer (WGET) mechanisms. Moreover, a comparison between WGET and FRET revealed the superiority of WGET in the context of building sensors with improved sensitivity and longer range of detection. In the last part of the thesis, a strategy is discussed in detail to provide biological functionalities to these optical microcavities which would enable them to interact with target analytes such as DNA, RNA, and proteins with high specificity, and moreover to reduce non-specific interactions. This strategy then was adapted to attach DNA capture probes onto the WGM enabled microcavities. Using the DNA attached microspheres as optical donor in combination with probe-DNA functionalized dye nanoparticles as optical acceptors, a biosensing assay has been successfully demonstrated to detect a cancer biomarker DNA called survivin in the solution phase. This assay did not only show good sensitivity towards the target, but also it has proven to be highly specific. The detection scheme has been demonstrated in a sophisticated confocal microscope at the single microsphere level, then successfully translated to a much simpler spectrofluorometer that measures fluorescence from the whole sample solution; the signature of the sandwich complex formation was also effectively detected.In conclusion, I demonstrated that microcavity-assisted energy transfer has several advantages over regular FRET assays. A real bio-sensing assay based on the WGET principle has also been successfully designed to detect cancer biomarkers with high sensitivity and specificity. This study thus opens up many possibilities to design high-performing and more accurate assays to detect varieties of biological entities