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Amphiphilic self-indicating and responsive polymer-based prodrugs have generated much interest as potential stimuli-responsive intelligent drug delivery systems (DDS) due to their ability to selectively deliver drugs to the cancer cells and to monitor real-time cellular uptake of the drug by imaging technique(s). In this direction, we have synthesized a new pH-responsive N-vinyl-2-pyrrolidone and coumarin-based fluorescent self-indicating polymeric prodrug (SIPD), poly(NVP)-b-poly(FPA.DOX-r-FPA-r-CA). This block copolymer prodrug self-assembled into stable micellar nanoparticles under physiological conditions that reduced undesirable drug leakage to normal cells but resulted in the release of the anticancer drug doxorubicin (DOX) in cancer cells because of acidic pH-induced cleavage of imine bonds between DOX and the copolymer. While the polymer was found to be highly biocompatible with both normal (HEK-293) cells and cancer (MCF-7) cells even at high concentrations by MTT assay, the polymer prodrug nanoparticles showed toxicity even higher than that of free DOX in cancer cells. Phase contrast microscopy also depicted the cytotoxic effects of the nanoparticles on cancer cells. The coumarin units present in the polymer served as a fluorescence resonance energy transfer (FRET) pair with the covalently attached DOX molecules, which was established by steady-state and time-resolved fluorescence spectroscopy. Furthermore, confocal microscopy results confirmed the FRET phenomenon, as the fluorescence intensity of coumarin in the micellar nanoparticles remained quenched initially in MCF-7 cells but recovered with time as the DOX molecules were released and gradually shifted toward the targeted nucleus. All of these studies implied that the synthesized prodrug nanoparticles may provide another viable option for delivering chemotherapeutic drugs into cancer cells with a capability of real-time monitoring of drug release.
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Rapid proliferation and a faster rate of glycolysis in cancer cells often result in an elevated local temperature (40-43 °C) at the tumor site. Nanoparticles prepared from polymers with two lower critical solution temperatures (LCSTs) can be utilized to take advantage of this subtle temperature elevation to deliver anticancer drugs preferably to the cancer cells, thereby enhancing the overall therapeutic efficacy and reducing side effects. In this direction, we synthesized N-vinyl-2-pyrrolidone (NVP) and substituted NVP (sub-NVP: C2-NVP, C4-NVP)-based polymers with precisely controlled LCSTs by varying the ratio of NVP and sub-NVP. The first LCST (LCST1) was kept below 37 °C to promote self-assembly, drug loading, and structural stability in physiological conditions and the second LCST (LCST2) was in the range of 40-43 °C to ensure mild hyperthermia-induced drug release. Additionally, covalent attachment of tetraphenylethylene (TPE, AIEgen) resulted in aggregation-induced emission in thermoresponsive micellar nanoparticles in which TPE acted as a Förster Resonance Energy Transfer (FRET) pair with the loaded anticancer drug doxorubicin (DOX). Tracking of FRET-induced fluorescence recovery of TPE molecules was utilized to confirm the real-time thermoresponsive release of DOX from nanoparticles and eventual localization of TPE in the cytoplasm and DOX in the nucleus. In vitro cellular studies such as cytotoxicity, cellular uptake, and thermoresponsive drug release showed that the DOX-loaded polymeric nanoparticles were nontoxic to normal cells (HEK-293) but significantly more effective in cancer cells (MCF-7) at 40 °C. To our knowledge, this is the first report of preferential delivery of anticancer drugs only by exploiting the slightly elevated temperature of cancer cells.
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Doxorrubicina , Liberación de Fármacos , Nanopartículas , Polímeros , Humanos , Nanopartículas/química , Doxorrubicina/farmacología , Doxorrubicina/química , Doxorrubicina/administración & dosificación , Polímeros/química , Pirrolidinonas/química , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/administración & dosificación , Micelas , Temperatura , Sistemas de Liberación de Medicamentos/métodos , Células MCF-7 , Portadores de Fármacos/química , Transferencia Resonante de Energía de Fluorescencia , Neoplasias/tratamiento farmacológico , Neoplasias/patología , EstilbenosRESUMEN
The present study reports the synthesis of micellar conjugates, wherein curcumin (Cur), a bioactive compound with poor bioavailability, was covalently bonded to a bacterial exopolysaccharide (EPS). These conjugates were synthesized by utilizing succinic acid that linked Cur to the pyranosyl moiety of the EPS. The Cur-EPS conjugates appeared as spherical micelles in aqueous solution and were found to have an average hydrodynamic diameter of 254 ± 2.7 nm. The micellar conjugates showed superior stability than Cur as evident from their negative surface charge (-27 ± 1.8 mV) and low polydispersity index (PDI) (0.33 ± 0.04). The in vitro studies on release kinetics helped elucidate the pH-responsive characteristics of the Cur-EPS conjugate, as 87.50 ± 1.45 % of Cur was released at an acidic pH of 5.6, in contrast to 30.15 ± 2.61 % at systemic pH of 7.4 at 150 h. The conjugates were hemocompatible and exhibited cytotoxic effect against the osteosarcoma cell line (MG-63) after 48 h treatment. They also demonstrated superior antibacterial, antibiofilm, and antioxidant activities in comparison to free Cur. Therefore, the Cur-EPS conjugates have potential pharmaceutical applications as therapeutic biomaterial that can be applied as a drug delivery system.
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Antineoplásicos , Neoplasias Óseas , Curcumina , Humanos , Curcumina/química , Micelas , Antineoplásicos/química , Sistemas de Liberación de Medicamentos , Neoplasias Óseas/tratamiento farmacológico , Concentración de Iones de Hidrógeno , Portadores de Fármacos/químicaRESUMEN
Targeted delivery of site-specific therapeutic agents is an effective strategy for osteoarthritis treatment. The lack of blood vessels in cartilage makes it difficult to deliver therapeutic agents like peptides to the defect area. Therefore, nucleus-targeting zwitterionic carbon nano-dots (CDs) have immense potential as a delivery vehicle for effective peptide delivery to the cytoplasm as well as nucleus. In the present study, nucleus-targeting zwitterionic CDs have been synthesized as delivery vehicle for peptides while also working as nano-agents towards optical monitoring of cartilage healing. The functional groups of zwitterion CDs were introduced by a single-step microwave assisted oxidation procedure followed by COL II peptide conjugation derived from Capra auricular cartilage through NHS/EDC coupling. The peptide-conjugated CDs (PCDs) allows cytoplasmic uptake within a short period of time (â¼30 m) followed by translocation to nucleus after â¼24 h. Moreover, multicolor fluorescence of PCDs improves (blue, green, and read channel) its sensitivity as an optical code providing a compelling solution towards enhanced non-invasive tracking system with multifunctional properties. The PCDs-based delivery system developed in this study has exhibited superior ability to induce ex-vivo chondrogenic differentiation of ADMSCs as compared to bare CDs. For assessment of cartilage regeneration potential, pluronic F-127 based PCDs hydrogel was injected to rabbit auricular cartilage defects and potential healing was observed after 60 days. Therefore, the results confirm that PCDs could be an ideal alternate for multimodal therapeutic agents.
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Temozolomide (TMZ) is the leading chemotherapeutic agent used for glioma therapy due to its good oral absorption and blood-brain barrier permeability. However, its anti-glioma efficacy may be limited due to its adverse effects and resistance development. O6-Methylguanine-DNA-methyltransferase (MGMT), an enzyme associated with TMZ resistance, is activated via the NF-κB pathway, which is found to be upregulated in glioma. TMZ also upregulates NF-κB signaling like many other alkylating agents. Magnolol (MGN), a natural anti-cancer agent, has been reported to inhibit NF-κB signaling in multiple myeloma, cholangiocarcinoma, and hepatocellular carcinoma. MGN has already shown promising results in anti-glioma therapy. However, the synergistic action of TMZ and MGN has not been explored. Therefore, we investigated the effect of TMZ and MGN treatment in glioma and observed their synergistic pro-apoptotic action in both in vitro and in vivo glioma models. To explore the mechanism of this synergistic action, we found that MGN inhibits MGMT enzyme both in vitro and in vivo glioma. Next, we established the link between NF-κB signaling and MGN-induced MGMT inhibition in glioma. MGN inhibits the phosphorylation of p65, a subunit of NF-κB, and its nuclear translocation to block NF-κB pathway activation in glioma. MGN-induced NF-κB inhibition results in the transcriptional inhibition of MGMT in glioma. TMZ and MGN combinatorial treatment also impedes p65 nuclear translocation to inhibit MGMT in glioma. We observed a similar effect of TMZ and MGN treatment in the rodent glioma model. Thus, we concluded that MGN potentiates TMZ-induced apoptosis in glioma by inhibiting NF-κB pathway-mediated MGMT activation.
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Glioma , FN-kappa B , Humanos , Temozolomida/farmacología , Temozolomida/uso terapéutico , FN-kappa B/metabolismo , Antineoplásicos Alquilantes/farmacología , Antineoplásicos Alquilantes/uso terapéutico , Línea Celular Tumoral , Glioma/tratamiento farmacológico , Glioma/genética , Glioma/metabolismo , Metilasas de Modificación del ADN/uso terapéutico , Proteínas Supresoras de Tumor/genética , Enzimas Reparadoras del ADN/genética , Enzimas Reparadoras del ADN/uso terapéuticoRESUMEN
Glioma is difficult-to-treat because of its infiltrative nature and the presence of the blood-brain barrier. Temozolomide is the only FDA-approved drug for its management. Therefore, finding a novel chemotherapeutic agent for glioma is of utmost importance. Magnolol, a neolignan, has been known for its apoptotic role in glioma. In this work, we have explored a novel anti-glioma mechanism of Magnolol associated with its role in autophagy modulation. We found increased expression levels of Beclin-1, Atg5-Atg12, and LC3-II and lower p62 expression in Magnolol-treated glioma cells. PI3K/AKT/mTOR pathway proteins were also downregulated in Magnolol-treated glioma cells. Next, we treated the glioma cells with Insulin, a stimulator of PI3K/AKT/mTOR signaling, to confirm that Magnolol induced autophagy by inhibiting this pathway. Insulin reversed the effect on Magnolol-mediated autophagy induction. We also established the same in in vivo glioma model where Magnolol showed an anti-glioma effect by inducing autophagy. To confirm the cytotoxic effect of Magnolol-induced autophagy, we used Chloroquine, a late-stage autophagy inhibitor. Chloroquine efficiently reversed the anti-glioma effects of Magnolol both in vitro and in vivo. Our study revealed the cytotoxic effect of Magnolol-induced autophagy in glioma, which was not previously reported. Additionally, Magnolol showed no toxicity in non-cancerous cell lines as well as rat organs. Thus, we concluded that Magnolol is an excellent candidate for developing new therapeutic strategies for glioma management.
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Antineoplásicos , Glioma , Insulinas , Lignanos , Ratas , Animales , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Antineoplásicos/farmacología , Lignanos/farmacología , Lignanos/uso terapéutico , Glioma/tratamiento farmacológico , Glioma/metabolismo , Autofagia , Cloroquina/farmacología , Cloroquina/uso terapéutico , Insulinas/farmacología , Insulinas/uso terapéutico , Línea Celular Tumoral , ApoptosisRESUMEN
Defect engineering, such as modification of oxygen vacancy density, has been considered as an effective approach to tailor the catalytic performance on transition-metal oxide nanostructured surfaces. The role of oxygen vacancies (OV) on the surface of the as-prepared, zinnia-shaped morphology of CuO nanostructures and their marigold forms on calcination at 800 °C has been investigated through the study of model catalytic reactions of reduction of 4-nitrophenol and aerobic oxidation of benzyl alcohol. The OV on the surfaces of different morphologies of CuO have been identified and quantified through Rietveld analysis and HRTEM, EPR, and XPS studies. The structure-activity relationships between surface oxygen vacancies (OV) and catalytic performance have been systematically investigated. The enhanced catalytic performance of the cubic CuO nanostructures compared to their as-prepared forms has been attributed to the formation of surface oxygen species on the reactive and dominant (110) surface that has low oxygen vacancy formation energy. The mechanistic role of surface oxygen species in the studied reactions has been quantitatively correlated with the catalytic activity of the different morphological forms of the CuO nanostructures.
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An ideal DNA carrier is one that is capable of effectively condensing DNA into complexes of optimum size and shape, preventing premature decomplexation in the bloodstream and efficiently releasing the DNA into affected cells. In this context, we have developed a novel ß-cyclodextrin (ß-CD)-based four-arm star-shaped polymer inclusion complex (IC) with arms made of a poly(l-histidine)-based cationic polymer. The polymer was well characterized by gel permeation chromatography, NMR, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. We have also investigated its DNA complexation and release properties. Bisadamantane containing a disulfide bond was synthesized that linked two such poly(l-histidine)-containing ß-CD units via guest-host interactions to prepare the presented IC. Besides using the conventional steady-state fluorescence spectroscopy, the ability of this IC to condense DNA to form polyplexes and their release behavior have been established by using the time-resolved fluorescence spectroscopy technique. Thiazole orange (TO) was used for the first time as a DNA-intercalating dye in the time-resolved fluorescence spectroscopic study. The superior DNA-condensing ability of the IC as compared to that of the precursor two-arm ß-CD and linear poly(l-histidine) of a comparable molecular weight, as confirmed by dynamic light scattering, zeta potential, atomic force microscopy, and gel electrophoresis studies, could be attributed to a higher charge density. The IC-DNA polyplexes were found to be stable in a medium similar to an extracellular fluid but could efficiently release DNA in the presence of 10 mM glutathione, a concentration prevalent in the intracellular fluid of cancer cells. Hence, here, we have successfully demonstrated the synthesis of a novel biocompatible star-shaped IC with the potential to carry and release DNA in cancer cells and also established the feasibility of using the time-resolved fluorescence spectroscopic technique to study the complexation behavior of the polycation and DNA using TO as a DNA-intercalating dye.
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Histidina , Polímeros , ADN , Microscopía de Fuerza Atómica , Peso MolecularRESUMEN
Multicellular tumor spheroid (MCTS) mimics microenvironment for tumor formation and provides predictive insight for in vivo tests. The hanging drop (HD) method of spheroid generation is cost effective, but it is limited by a long time duration for spheroid development and a low rate of formation of larger spheroids. Toward addressing those limitations, thermoresponsive copolymers with poly(N-isopropylacrylamide) (p(NIPA)) backbone are developed, to be used as additives in the MCTS formation via HD method. Upon investigation it is found that in the presence of the polymer, robust and compact spheroids are formed in a short duration of 48 h. Larger spheroids (350-600 µm) can be formed by increasing the number of cells. Spheroids are characterized for their 3D shape and different cellular layers, and drug uptake study is done to prove the efficacy of the spheroids generated in drug screening.
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Resinas Acrílicas/química , Esferoides Celulares/citología , Resinas Acrílicas/síntesis química , Recuento de Células , Muerte Celular , Línea Celular Tumoral , Tamaño de la Célula , Supervivencia Celular , Humanos , Procesamiento de Imagen Asistido por Computador , Cinética , TemperaturaRESUMEN
Disruption of DNA carriers triggered by intracellular bio-stimulants has been broadly considered as most convenient strategy for efficient DNA delivery. In this direction, we have designed and synthesized pH, redox and ATP responsive cationic cross-linked polymers (CLPs) having disulfide and reversible boronic ester linkages. These CLPs also contain folate groups that are known for their targeting capability towards cancer cells. Biophysical studies showed that these cationic CLPs exhibited more effective DNA condensation in comparison to cationic linear polymers resulting in the formation of nano-sized polyplexes with sufficient positive zeta potentials and good colloidal stability at neutral pH (â¼7.4). More interestingly, the polyplexes prepared from these CLPs have the ability to selectively release complexed DNA under conditions similar to those prevalent in cancer cells such as acidic pH, ATP rich surroundings or presence of glutathione, as revealed by ethidium bromide exclusion assay, agarose gel electrophoresis, AFM measurements, etc. Therefore, these cross-linked polymers have high potential of being effective non-viral gene delivery vehicles.
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Boro/química , Cationes/química , Reactivos de Enlaces Cruzados/química , ADN/metabolismo , Disulfuros/química , Ésteres/química , Polímeros/química , ADN/química , HumanosRESUMEN
An efficient Rh(iii)-catalyzed straightforward strategy was developed for the tandem C4 arylamination/annulation of indole derivatives with anthranil to provide indoloquinoline moieties. This method is simple and regioselective with a wide scope and functional group tolerance. Mechanistic studies revealed the important role of the newly installed azacycle in the conversion of O-protected aldoximes to their cyano derivatives. Studies were carried out to explore the promising photophysical properties of the obtained indoloquinoline derivatives.
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Cationic polymeric micelles that are capable of co-releasing drugs and DNA into cells have attracted considerable interest as combination chemotherapy in cancer treatment. To this effect, we have presently developed a cationic fluorescent amphiphilic copolymer, poly(N,N'-dimethylaminoethylmethacrylate)-b-(poly(2-(methacryloyl)oxyethyl-2'-hydroxyethyl disulfidecholate)-r-2-(methacryloyloxy)ethyl-1-pyrenebutyrate) [PDMAEMA-b-(PMAODCA-r-PPBA)], having pendent cholate moiety linked through a redox-responsive disulfide bond. The amphiphilic nature of the copolymer facilitated the formation of cationic micellar nanoparticles in aqueous medium. The self-assembly of the copolymer to form micelles and subsequent destabilization of the micelles in the presence of glutathione (GSH) was monitored by the change in the fluorescence characteristic of the attached pyrene resulting from alteration in the hydrophobicity of its neighborhood. These micellar nanoparticles were subsequently utilized in encapsulating hydrophobic anticancer drug, doxorubicin (DOX), in the core of the micelles, whereas the cationic shell of the micelles was used for complexation with oppositely charged DNA to form micelleplexes. Gel retardation assays, ethidium bromide (EB) exclusion assay, and DLS and AFM studies confirmed the successful binding of the cationic micelles with DNA. The binding capability of the micelles was higher than corresponding cationic linear PDMAEMA. The kinetics of the simultaneous release of encapsulated DOX and complexed DNA in the presence of glutathione was thoroughly studied using various techniques. All the experiments showed fast and efficient release of DOX and DNA from DOX-loaded micelleplexes. The study implies that these redox-responsive cationic micelles may open up new opportunities toward co-delivery of DNA and anticancer drugs in combinatorial therapy.
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Antineoplásicos/química , ADN de Neoplasias/química , Doxorrubicina/química , Colorantes Fluorescentes/química , Polímeros/química , Tensoactivos/química , Cationes/síntesis química , Cationes/química , Liberación de Fármacos , Colorantes Fluorescentes/síntesis química , Interacciones Hidrofóbicas e Hidrofílicas , Micelas , Estructura Molecular , Oxidación-Reducción , Tamaño de la Partícula , Polímeros/síntesis química , Propiedades de Superficie , Tensoactivos/síntesis químicaRESUMEN
The stability of a drug payload inside a nanocarrier at physiological environment and the release of the said drug at specific tumor cells in a sustainable manner are the two most important factors that determine the efficiency of a smart targeted drug-delivery system. In this work, 2-hydroxyethyl methacrylate and a coumarin-based methacrylate monomer containing ß-thiopropionate moiety were copolymerized via reversible addition-fragmentation chain transfer (RAFT) process, followed by characterization using NMR and GPC. The said copolymer self-assembled at physiological pH to form vesicular nano-aggregates which was confirmed using DLS, TEM and by fluorescence measurements. These vesicles were further stabilized by photochemical crosslinking via coumarin (2πâ¯+â¯2π) cycloaddition reaction. These cross-linked vesicles (CVs) exhibited a 38% reduction in premature drug leakage as compared to the uncross-linked vesicles (UCVs) at physiological pH. Additionally, a slow hydrolysis of the ß-thiopropionate moieties under mildly acidic conditions prevalent in tumor cells resulted in disassembly of the vesicles, thereby releasing the loaded drug in a sustainable manner. Studies related to in vitro toxicity, efficiency of cellular uptake and pH-responsive antineoplastic activity of doxorubicin (DOX) loaded in the cross-linked vesicles (CVs) toward cancer cell lines were undertaken. A significant reduction in IC50 was noticed for DOX-loaded CVs in comparison to free DOX toward MG63 cancer cell lines, making these vesicles as potent nanocarrier systems for cancer therapy.
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Antibióticos Antineoplásicos/farmacología , Cumarinas/química , Reactivos de Enlaces Cruzados/química , Doxorrubicina/farmacología , Osteosarcoma/tratamiento farmacológico , Polímeros/química , Antibióticos Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Doxorrubicina/química , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Concentración de Iones de Hidrógeno , Estructura Molecular , Osteosarcoma/patología , Tamaño de la Partícula , Procesos Fotoquímicos , Polímeros/síntesis química , Propiedades de SuperficieRESUMEN
Glioma is one of the most perplexing cancers because of its infiltrating nature, molecular signaling, and location in central nervous system. Blood-brain barrier acts as a natural barrier to the glioma making it difficult to access by conventional chemotherapy. Clinicians are using natural compounds or their derivatives for several diseases including different cancers. However, the feasibility of using natural compounds in glioma is not explored in details. Natural compounds can act over a wide variety of signaling pathways such as survival and metabolic pathways and induce cell death. Some of the natural agents have additional benefits of crossing biological barriers such as blood-brain barrier with ease having few or no impact on the surrounding healthy cells. All of these benefits make natural compounds a prospective candidate for the glioma management. This article evaluates the benefits of using natural compounds for glioma therapy and their possible mechanism of actions. We have discussed the natural compounds assessed currently for glioma therapy and proposed a few novel natural compounds with potential antiglioma effect based on their mechanism of action.
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Productos Biológicos/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Glioma/tratamiento farmacológico , Animales , Productos Biológicos/farmacocinética , Productos Biológicos/farmacología , Barrera Hematoencefálica , HumanosRESUMEN
Success of chemotherapy as a treatment for cancer has been often inhibited by multidrug resistance (MDR) of the cancer cells. There is a clear need to generate strategies to overcome this resistance. In this work, we have developed redox-responsive and core-cross-linked micellar nanocarriers using poly(ethylene glycol)-block-poly(2-(methacryloyloxy)ethyl 5-(1,2-dithiolan-3-yl)pentanoate) diblock copolymers (PEG-b-PLAHEMA) with tunable swelling properties for the delivery of drugs toward drug-sensitive MDA-MB-231 and drug-resistant MDA-MB-231 (231R) cancer cells. PEG-b-PLAHEMA containing varying number of 2-(methacryloyloxy)ethyl 5-(1,2-dithiolan-3-yl)pentanoate (LAHEMA) units were synthesized by employing the reversible addition-fragmentation chain transfer polymerization technique. The block copolymer self-assembly, cross-linking induced by reduction, and de-cross-linking triggered time-dependent controlled swelling of micelles were studied using dynamic light scattering, fluorescence spectroscopy, and transmission electron microscopy. In vitro cytotoxicity, cellular uptake efficiency, and glutathione-responsive anticancer activity of doxorubicin (DOX) encapsulated in core-cross-linked block copolymer micelles (CCMs) toward both drug-sensitive and drug-resistant cancer cell lines were evaluated. Significant reduction in IC50 was observed by DOX-loaded CCMs toward drug-resistant 231R cancer cell lines, which was further improved by coencapsulating DOX and verapamil (a P-glycoprotein inhibitor) in CCMs. Thus, these reduction-sensitive biocompatible CCMs with tunable swelling property are very promising in overcoming MDR in cancer cells.
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Polímeros/química , Línea Celular Tumoral , Doxorrubicina , Portadores de Fármacos , Resistencia a Múltiples Medicamentos , Resistencia a Antineoplásicos , Humanos , Micelas , Oxidación-Reducción , PolietilenglicolesRESUMEN
In this work, synthesis of two cross-linked polymeric systems through isoxazoline ring formation using nitrile oxide-acrylate click chemistry has been described. In the first system, styrenic block copolymer with oxime-functionalized middle block was synthesized using S,S'-bis(α,α'-dimethyl-αâ³-acetic acid)trithiocarbonate as chain-transfer agent using reversible addition fragmentation chain-transfer technique. This block copolymer was further utilized to prepare core cross-linked star polymers by reacting with a four-arm acrylic cross-linker by employing environment-friendly, nontoxic PhI(OAc)2-mediated "click reaction" via the formation of isoxazoline ring. In the second system, two linear styrenic block copolymers, one containing oxime and another containing acrylate group, were reacted to form a cross-linked (CS) polymeric system. Formation of cross-linked polymers and isoxazoline ring was confirmed by Fourier transform infrared spectroscopy, gel permeation chromatography, NMR spectroscopy, and dynamic light scattering studies. Later, we also demonstrated that in aqueous medium these CS polymers produced polymeric nanoparticles (NPs), which can be used as potential carriers of hydrophobic drug molecules. The loading capacity of the hydrophobic domains has been investigated using coumarin dyes with varying hydrophobicity through steady-state and time-resolved spectroscopy studies. The polymeric NPs were also shown to successfully encapsulate a hydrophobic drug doxorubicin.
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We describe the development of a polymeric vesicle that not only selectively fluoresces at low pH, a condition prevailing in cancer cells, but also can potentially monitor the thermoresponsive release of a drug even if the drug is nonfluorescent. The developed fluorescence resonance energy transfer (FRET)-based thermoresponsive vesicular nanocarriers are composed of a new poly(PEGMA)-b-poly(NIPA-r-R6GMED) block copolymer, which undergoes pH-switchable superior turn on-off fluorescence characteristics. The block copolymer was synthesized using the RAFT technique, and its solution properties and self-assembly behavior were investigated by turbidity measurements, fluorescence spectroscopy, 1H NMR, dynamic light scattering, and transmission electron microscopy. The block copolymer self-assembled to form nanostructured vesicles above the critical aggregation temperature under physiologically relevant conditions. Steady-state and time-resolved fluorescence spectroscopy were utilized to study the FRET process between encapsulated hydrophobic guest C-153 (donor) and polymer-bound R6GMED units (acceptor) in the thermoresponsive vesicles. The FRET rate and efficiency were found to vary as a result of the pH-dependent changes in the quantum yield of the acceptor molecules. The occurrence of a highly efficient FRET in this polymeric vesicular nanocarrier at acidic pH, a condition similar to the cytoplasm and cell nucleus in leukemic tissues, and the ability to encapsulate hydrophilic and hydrophobic molecules and their temperature-controlled release make it potentially useful in imaging guided real-time monitoring of drug-delivery vehicles.
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In this article, we have reported the synthesis and physicochemical characterization of a novel l-glycine amino acid derived cholesterol based surface active ionic liquid (SAIL). This SAIL has been explored for the preparation of ionic liquid (IL)-in-oil microemulsions and vesicles. The formation of IL-in-oil microemulsion is characterized by construction of a ternary phase diagram, dynamic light scattering (DLS) measurement, proton nuclear magnetic resonance (1H NMR) study, fluorescence measurement using coumarin 480 (C-480) as a molecular probe, and also by recording the diffusion behavior of the molecular probe rhodamine 6G (R6G) in microemulsion droplets through the fluorescence correlation spectroscopy (FCS) technique. Similarly, the spontaneous vesicle formation from the SAIL in water has been established using DLS, transmission electron microscopy (TEM), cryogenic-transmission electron microscopy (cryo-TEM), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), FCS, and fluorescence lifetime imaging microscopy (FLIM) measurements. These aggregates may potentially serve as good biomimicking models and possible drug carriers.
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BACKGROUND: Gold nanorods, by virtue of surface plasmon resonance, convert incident light energy (NIR) into heat energy which induces hyperthermia. We designed unique, multifunctional, gold nanorod embedded block copolymer micelle loaded with GW627368X for targeted drug delivery and photothermal therapy. METHODS: Glutathione responsive diblock co-polymer was synthesized by RAFT process forming self-assembled micelle on gold nanorods prepared by seed mediated method and GW627368X was loaded on to the reduction responsive gold nanorod embedded micelle. Photothermal therapy was administered using cwNIR laser (808nm; 4W/cm2). Efficacy of nanoformulated GW627368X, photothermal therapy and combination of both were evaluated in vitro and in vivo. RESULTS: In response to photothermal treatment, cells undergo regulated, patterned cell death by necroptosis. Combining GW627368X with photothermal treatment using single nanoparticle enhanced therapeutic outcome. In addition, these nanoparticles are effective X-ray CT contrast agents, thus, can help in monitoring treatment. CONCLUSION: Reduction responsive nanorod embedded micelle containing folic acid and lipoic acid when treated on cervical cancer cells or tumour bearing mice, aggregate in and around cancer cells. Due to high glutathione concentration, micelles degrade releasing drug which binds surface receptors inducing apoptosis. When incident with 808nm cwNIR lasers, gold nanorods bring about photothermal effect leading to hyperthermic cell death by necroptosis. Combination of the two modalities enhances therapeutic efficacy by inducing both forms of cell death. GENERAL SIGNIFICANCE: Our proposed treatment strategy achieves photothermal therapy and targeted drug delivery simultaneously. It can prove useful in overcoming general toxicities associated with chemotherapeutics and intrinsic/acquired resistance to chemo and radiotherapy.
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Sistemas de Liberación de Medicamentos/métodos , Oro/química , Hipertermia Inducida , Micelas , Nanotubos/química , Neoplasias/terapia , Fototerapia , Polímeros/química , Animales , Materiales Biocompatibles/farmacología , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Medios de Contraste/química , Liberación de Fármacos , Endocitosis/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Isoindoles/farmacología , Ratones , Nanotubos/ultraestructura , Polímeros/síntesis química , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja Corta , Sulfonamidas/farmacología , Rayos XRESUMEN
In recent decades, drug delivery systems (DDSs) based on polymer nanoparticles have been explored due to their potential to deliver drugs with poor water solubility. Some of the limitations of nanoparticle-based DDSs can be overcome by developing an appropriate polymer prodrug. In this work, poly(NIPA)-b-poly(HMNPPA)-b-poly(PEGMA-stat-BA) was synthesized using reversible addition fragmentation chain transfer polymerization and Chlorambucil (Cbl), an anticancer drug, was conjugated to the copolymer via 3-(3-(hydroxymethyl)-4-nitrophenoxy)propyl acrylate (HMNPPA) units to prepare the prodrug. A few biotin acrylate (BA) units were also incorporated to bring potential targeting capability to the prodrug in the copolymer. This polymer prodrug formed spherical micellar nanoparticles in physiological conditions, which were characterized by dynamic light scattering and transmission electron microscopy measurements. The very low critical aggregation concentration (cac) (0.011 mg/mL) of the prodrug, as measured from Nile Red fluorescence, makes it stable against dilution. The polymer prodrug was shown to release Cbl on photoirradiation by soft UV (λ ≥ 365 nm) and laser (λ = 405 nm) light. The prodrug micellar nanoparticles were capable of encapsulating a second drug (doxorubicin, DOX) in their hydrophobic core. On photoirradiation with UV and laser light of the DOX-loaded nanoparticles, both Cbl and DOX were released. Light-induced breaking of photolabile ester bond resulted in the release of Cbl and caused disruption of the nanoparticles facilitating release of DOX. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay confirmed the nontoxicity of the polymers and effectiveness of the dual drug-loaded micellar nanoparticles toward cancer cells. Confocal microscopy results showed a better cellular internalization capability of the DOX-loaded nanoparticles in cancer cells, possibly due to the presence of cancer cell targeting biotin molecules in the polymer. This new photoresponsive potentially biocompatible and cancer cell-targeted polymer prodrug may be useful for delivery of single and/or multiple hydrophobic drugs.