20 research outputs found

    Development of in-situ produced CO2 switchable fatty acid microextraction based solidification of floating organic droplet for quantification of morin and quercetin in tea, vegetable and fruit juice samples by HPLC

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    An in-situ produced CO2 switchable fatty acid microextraction based on solidification of floating organic droplet (In-situ-CO2-SFA-ME-SFO) was evaluated for microextraction of two antioxidant flavonoids (morin and quercetin) in tea, fruit juice and vegetable samples prior to HPLC-UV. Medium-chain fatty acids (e.g. nonanoic acid) were investigated as switchable hydrophilicity solvents via pH adjustment. Sodium carbonate (Na2CO3) was used to solubilize immiscible fatty acid in water as well as, to provide effervescence. The addition of H2SO4 into the solution led to the in-situ chemical reaction with excess Na2CO3 which resulted in effective dispersion of fatty acid through generated CO2 and separation of phases. Subsequently, solidification of the fatty acid enabled facile separation without the need for sophisticated equipment. To optimize extraction process, the effects of some important parameters on the extraction recovery were investigated. At the optimum conditions, the limits of detection (LODs) and the limits of quantification (LOQs) were found 0.5 and 1.3 ”g L−1 and 1.6 and 4.3 ”g L−1 for morin and quercetin respectively. The preconcentration factors were 105 while, the relative standard deviations (RSDs %) of the method were < 3.5 % for both flavonoids. The recoveries of the analytes in tea, vegetable and fruit juice samples were in the range of 95.5 and 98.2

    Controlled Delivery of Nitric Oxide Using Stable and Stimuli-Responsive S-nitrosothiols

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    Nitric oxide (NO) is a short-lived, endogenously produced gas which plays multiple roles in mammalian physiology. A broad range of NO donors has emerged as potential therapeutics in different pathological processes including cardiovascular and respiratory disorders, wound healing, the immune response to infection and cancer. However, limited NO payloads, too rapid NO release, and the lack of organ or tissue specificity have limited the clinical utility of currently available NO donors. Herein, three main strategies were used to make stable and stimuli-responsive NO donors using S-nitrosothiols (SNTs). First, we have developed photoactive nanoparticles (NPs) by encapsulation of a hydrophobic and stable SNT, tert-dodecane s-nitrosothiol (tDodSNO), into polystyrene maleic acid (SMA) to make nano-sized SMA-tDodSNO particles. Encapsulation of tDodSNO physically protects it from metabolic breakdown as well as trans-nitrosation reactions with proteins and thiols, thereby inhibits unspecific NO release. In the absence of photo-irradiation, NPs had a half-life (t1/2) of approximately 104 h, while photoactivation (cold light with the intensity of 2700 W/m2) decreased this to just 3.5 min. Second, a stable and tuneable NO-releasing compound was synthesized which contains hydrophobic and sterically hindered SNT as well as a carboxylate group far from the SNT group. The compound showed sustained NO release in the dark (t1/2= 300 h) while upon photoactivation is degraded within a few mins (t1/2= 5.5 min). Third, by combining these two approaches and attachment of the synthesized SNT to SMA to produce a novel NO-releasing polymer (SMASNO). The unactivated polymer has a NO release half-life of approximately 392 h, and photoactivation decreased this to 23 min. Photoactivation of SMA-tDodSNO resulted in an 18-fold shift in the EC50 of rat’s aortic ring vasorelaxation and also induced localized hyperpermeability in rats mesenteric bed with microscopic analysis indicating that the SMA-tDodSNO increased tissue uptake through a combination of photoactivation induced vasodilation and extravasation. SMA-tDodSNO showed significant cytotoxicity in 4T1 cell line and when combined with doxorubicin (Dox) it synergistically arrested cell proliferation and induced apoptosis. Due to NO release, it enhanced the endocytosis of a Dox-loaded NP (SMA-Dox) and increased the permeability of the endosomal membrane, hence facilitated the escape of the NPs, and reduced Dox efflux from the cells. Similarly, photoactivation of SMASNO shifted the EC50 of the aortic ring to 12-fold lower concentrations. The polymer could self-assemble to form containing the hydrophobic fluorescent dye Nile Red (NR) as a traceable drug analog to form NRNPs. The NR release from the particles was increased in either the presence of high levels of glutathione or in response to photoactivation, indicating that the NP could release its cargo in response to specific stimuli. When NRNPs were perfused into a rat mesenteric bed, then a region of the bed irradiated by cold light was significantly higher than other parts of the bed. In conclusion, stable and stimuli-responsive NO-releasing compounds were made using hydrophobic and bulky SNTs covalently attached or self-assembled with hydrophilic moieties. We report that the stimuli-responsive NO-releasing NPs can be used to overcome some of the barriers in front of efficient chemotherapy, as they can enhance blood supply, vessel permeability in tumor tissues, endocytosis and endosomal escape of NPs, and inhibit drug resistance

    Controlled Delivery of Nitric Oxide Using Stable and Stimuli-Responsive S-nitrosothiols

    No full text
    Nitric oxide (NO) is a short-lived, endogenously produced gas which plays multiple roles in mammalian physiology. A broad range of NO donors has emerged as potential therapeutics in different pathological processes including cardiovascular and respiratory disorders, wound healing, the immune response to infection and cancer. However, limited NO payloads, too rapid NO release, and the lack of organ or tissue specificity have limited the clinical utility of currently available NO donors. Herein, three main strategies were used to make stable and stimuli-responsive NO donors using S-nitrosothiols (SNTs). First, we have developed photoactive nanoparticles (NPs) by encapsulation of a hydrophobic and stable SNT, tert-dodecane s-nitrosothiol (tDodSNO), into polystyrene maleic acid (SMA) to make nano-sized SMA-tDodSNO particles. Encapsulation of tDodSNO physically protects it from metabolic breakdown as well as trans-nitrosation reactions with proteins and thiols, thereby inhibits unspecific NO release. In the absence of photo-irradiation, NPs had a half-life (t1/2) of approximately 104 h, while photoactivation (cold light with the intensity of 2700 W/m2) decreased this to just 3.5 min. Second, a stable and tuneable NO-releasing compound was synthesized which contains hydrophobic and sterically hindered SNT as well as a carboxylate group far from the SNT group. The compound showed sustained NO release in the dark (t1/2= 300 h) while upon photoactivation is degraded within a few mins (t1/2= 5.5 min). Third, by combining these two approaches and attachment of the synthesized SNT to SMA to produce a novel NO-releasing polymer (SMASNO). The unactivated polymer has a NO release half-life of approximately 392 h, and photoactivation decreased this to 23 min. Photoactivation of SMA-tDodSNO resulted in an 18-fold shift in the EC50 of rat’s aortic ring vasorelaxation and also induced localized hyperpermeability in rats mesenteric bed with microscopic analysis indicating that the SMA-tDodSNO increased tissue uptake through a combination of photoactivation induced vasodilation and extravasation. SMA-tDodSNO showed significant cytotoxicity in 4T1 cell line and when combined with doxorubicin (Dox) it synergistically arrested cell proliferation and induced apoptosis. Due to NO release, it enhanced the endocytosis of a Dox-loaded NP (SMA-Dox) and increased the permeability of the endosomal membrane, hence facilitated the escape of the NPs, and reduced Dox efflux from the cells. Similarly, photoactivation of SMASNO shifted the EC50 of the aortic ring to 12-fold lower concentrations. The polymer could self-assemble to form containing the hydrophobic fluorescent dye Nile Red (NR) as a traceable drug analog to form NRNPs. The NR release from the particles was increased in either the presence of high levels of glutathione or in response to photoactivation, indicating that the NP could release its cargo in response to specific stimuli. When NRNPs were perfused into a rat mesenteric bed, then a region of the bed irradiated by cold light was significantly higher than other parts of the bed. In conclusion, stable and stimuli-responsive NO-releasing compounds were made using hydrophobic and bulky SNTs covalently attached or self-assembled with hydrophilic moieties. We report that the stimuli-responsive NO-releasing NPs can be used to overcome some of the barriers in front of efficient chemotherapy, as they can enhance blood supply, vessel permeability in tumor tissues, endocytosis and endosomal escape of NPs, and inhibit drug resistance

    Waste apple pomace conversion to acrylic acid: Economic and environmental assessment

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    The global demand for acrylic acid (AA) is increasing due to its wide range of applications. Due to this growing demand, alternative AA production strategies must be explored to avoid the exacerbation of prevailing climate and global warming issues since current AA production strategies involve AA production using fossil resources. Investigations on alternative strategies for AA production therefore constitute an important research interest. The present study therefore assesses waste apple pomace (WAP) as a feedstock for the sustainable AA produc-tion. To undertake this assessment, process models, based on two production pathways were designed, modelled and simulated in ASPEN plusÂź software. The two competing production pathways investigated include a process incorporating WAP conversion to lactic acid (LA), prior to LA dehydration to generate AA (denoted as the FD pathway) and another process involving WAP conversion to propylene, prior to propylene oxidation to generate AA (denoted as the TFO pathway). Economic and environmental performances of the FD and TFO pathways were assessed via the minimum selling price (MSP) and potential environmental impacts per h (PEI/h) metrics. The study was able to show that the FD pathway presented an improved economic performance (MSP of AA: US 1.17perkg)performancecomparedtotheeconomicperformance(MSPofAA:US1.17 per kg) performance compared to the economic performance (MSP of AA: US 1.56 per kg) of the TFO pathway. Crucially, the TFO process was shown to present an improved environmental performance (2.07 kPEI/h) compared to the environmental performance of the FD process (8.72 kPEI/h). These observations sug-gests that the selection of the preferred AA production will require a trade-off between the performance measures, and the integration of a multi-criteria decision assessment in future work

    Waste Apple Pomace Conversion to Acrylic Acid: Economic and Potential Environmental Impact Assessments

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    The global demand for acrylic acid (AA) is increasing due to its wide range of applications. Due to this growing demand, alternative AA production strategies must be explored to avoid the exacerbation of prevailing climate and global warming issues since current AA production strategies involve fossil resources. Investigations regarding alternative strategies for AA production therefore constitute an important research interest. The present study assesses waste apple pomace (WAP) as a feedstock for sustainable AA production. To undertake this assessment, process models based on two production pathways were designed, modelled and simulated in ASPEN plus¼ software. The two competing production pathways investigated included a process incorporating WAP conversion to lactic acid (LA) prior to LA dehydration to generate AA (denoted as the fermentation–dehydration, i.e. FD, pathway) and another process involving WAP conversion to propylene prior to propylene oxidation to generate AA (denoted as the thermochemical–fermentation–oxidation, i.e. TFO, pathway). Economic performance and potential environmental impact of the FD and TFO pathways were assessed using the metrics of minimum selling price (MSP) and potential environmental impacts per h (PEI/h). The study showed that the FD pathway presented an improved economic performance (MSP of AA: USD 1.17 per kg) compared to the economic performance (MSP of AA: USD 1.56 per kg) of the TFO pathway. Crucially, the TFO process was determined to present an improved environmental performance (2.07 kPEI/h) compared to the environmental performance of the FD process (8.72 kPEI/h). These observations suggested that the selection of the preferred AA production pathway or process will require a tradeoff between economic and environmental performance measures via the integration of a multicriteria decision assessment in future work.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Data characterizing the biophysical and nitric oxide release properties of the tDodSNO – Styrene maleic anhydride nanoparticle SMA-tDodSNO

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    Nitric oxide (NO) donor drugs have a range of clinical applications, and are also being developed as therapeutics for the potential treatment of multiple diseases. This article presents data describing the synthesis and characterisation of a novel NO releasing nanoparticle formed by encapsulation of the NO donor tDodSNO into a co-polymer of styrene and maleic acid (SMA) to afford SMA-tDodSNO. The pharmacological activity of SMA-tDodSNO is discussed in our accompanying manuscript “Encapsulation of tDodSNO generates a photoactivated nitric oxide releasing nanoparticle for localized control of vasodilation and vascular hyperpermeability”. (Alimoradio et al. [1])

    Enhanced keratin extraction from wool waste using a deep eutectic solvent

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    Abstract: In this study, the solubilization of waste coarse wool as a precursory step for the large-scale valorization of keratin was investigated using a green deep eutectic solvent (DES) based on L-cysteine and lactic acid. The investigation was undertaken via the response surface methodology and based on the Box–Behnken design for four process variables of temperature (70–110 °C), dissolution time (2–10 h), the mass of L-cysteine (0.5–2.5 g) in 20 mL of lactic acid, and wool load in the DES (0.2–0.6 g). Temperature was the most significant process variable influencing keratin yield from the waste coarse wool. The optimum keratin yield (93.77 wt.%) was obtained at the temperature of 105 °C, 8 h dissolution time, with 1.6 g L-cysteine in 20 mL of lactic acid using 0.5 g of wool. This study suggests L-cysteine and lactic acid as a green solvent with the potential to scale up keratin recovery from waste wool without significant destruction in the structure of the recovered keratin. Graphical abstract: [Figure not available: see fulltext.]SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Gas Therapy: Generating, Delivery, and Biomedical Applications

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    Abstract Oxygen (O 2 ), nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H 2 S), and hydrogen (H 2 ) with direct effects, and carbon dioxide (CO 2 ) with complementary effects on the condition of various diseases are known as therapeutic gases. The targeted delivery and in situ generation of these therapeutic gases with controllable release at the site of disease has attracted attention to avoid the risk of gas poisoning and improve their performance in treating various diseases such as cancer therapy, cardiovascular therapy, bone tissue engineering, and wound healing. Stimuli‐responsive gas‐generating sources and delivery systems based on biomaterials that enable on‐demand and controllable release are promising approaches for precise gas therapy. This work highlights current advances in the design and development of new approaches and systems to generate and deliver therapeutic gases at the site of disease with on‐demand release behavior. The performance of the delivered gases in various biomedical applications is then discussed.SCOPUS: re.jinfo:eu-repo/semantics/publishe
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