Increasing Glycerol Concentration Research Articles

Size of lipid emulsion droplets influences metabolism in human CD4+ T cells

ScopeTriglyceride-based lipid emulsions are critical for total parenteral nutrition (TPN), but their long-term use has adverse effects, such as severe liver dysfunction necessitating improved formulations. This study compares the uptake mechanism and intracellular fate of novel glycerol-stabilized nano-sized lipid emulsions with conventional emulsions in CD4+ T cells, focusing on their impact on cellular metabolism. Methods and resultsNanoemulsions were formulated with increased glycerol content. Uptake of emulsions in primary human CD4+ T cells was investigated using different endocytic blockers, then quantified by flow cytometry, and visualized by confocal microscopy. To investigate emulsion intracellular fate, fatty acids in membrane phospholipids were quantified by GC-MS/MS and cellular metabolism was assessed by Seahorse technology. Results show T cells internalize both conventional and nano-sized emulsions using macropinocytosis. Fatty acids from emulsions are stored as neutral lipids in intracellular vesicles and are incorporated into phospholipids of cellular membranes. However, only nanoemulsions additionally use clathrin-mediated endocytosis and deliver fatty acids to mitochondria for increased β-oxidation. ConclusionsSize of lipid emulsion droplets significantly influences their uptake and subsequent metabolism in CD4+ T cells. Our results highlight the potential for improved nutrient utilization with nanoemulsions in TPN formulations possibly leading to less adverse effects.

Development of active edible films from coffee pulp pectin, propolis, and honey with improved mechanical, functional, antioxidant, and antimicrobial properties

This study examined the impact of propolis and honey on the physicochemical, structural, antioxidant, and antibacterial properties of coffee pulp pectin-based edible films. The films were made from pure pectin (P) and mixtures of pectin-glycerol (PG), pectin-propolis-glycerol (PPG), and pectin-honey (PH). Pectin solutions were prepared by varying the pectin-to-water ratio between 1 % and 5 % (wpectin/vwater). Propolis, glycerol, and honey were then added to the solution, with the ratio of these ingredients to pectin ranging from 0 % to 60 %. The films were characterized for their physicochemical, structural, antioxidant, and antibacterial properties. The results showed that films made from 2 % pectin (P), 2 % pectin with 20 % propolis and 20 % glycerol (PPG), 2 % pectin with 20 % honey (PH), and 2 % pectin with 20 % glycerol (PG) exhibited higher elongation at break and better tensile strength. Higher pectin, honey, and glycol concentrations increase the film thickness. Similarly, Young's modulus increased with rising pectin concentration. The tensile strength of the films increased with glycerol concentration up to 20 %, after which it decreased. Young's modulus decreased with increasing glycerol concentration. Tensile strength and elongation at break improved with honey-to-pectin ratios up to 20 %, then declined with further increases. The water vapor permeability (WVP) values of the edible films ranged from 3.154 to 3.437 × 10−10 g/m·s·Pa. The films were fully degraded in soil within 9 days. The results suggest that adding honey and propolis enhanced the antioxidant and antibacterial properties of the films.

Nanocomposite films based on chia (Salvia hispanica L.) flour seeds incorporating antioxidant chitosan nanoparticles.

Chia (Salvia hispanica L.) flour seeds produce films with good barrier properties against water vapor and could be used as food packaging; however, their mechanical properties are poor, which limits their application. The incorporation of nanoparticles into natural polymers is a strategy used to improve the properties of films to increase their applications. Furthermore, nanoparticles can encapsulate antioxidant agents and generate active films. The objective of this study was to evaluate the influence of chia flour (4%-7%), glycerol (15%-25%), and chia extract-loaded chitosan nanoparticles (ChCNp) (0%-0.75%) on the physical, mechanical, barrier, structural and antioxidant properties of chia flour nanocomposite films. Chitosan nanoparticles loaded with antioxidant chia extract were synthesized by ionic gelation and incorporated into the films. The thickness, water vapor permeability, tensile strength, and antioxidant properties of the films were evaluated using a Box-Behnken experimental design. Structural analysis was conducted using the FTIR technique. The results of the ANOVA of the responses were adjusted to second and third order polynomial models obtaining determination coefficients of 0.96-0.99. The water vapor permeability of the films was 3.89 × 10-8-1.68 × 10-7gmm/Pa sm2, tensile strength was 0.67-3.59MPa and antioxidant activity was 57.12%-67.84%. The variables presented different effects on the films. Increasing the chia seed flour concentration negatively affected the water vapor permeability but improved the tensile strength and the antioxidant capacity of the films. The increase in glycerol concentration caused the films to become brittle. The nanoparticles had a significant effect on the thickness of the films and improved their mechanical and antioxidant properties. However, they did not show an effect on barrier properties. The results demonstrate that it is possible to obtain nanocomposite films with antioxidant capacity from chia seed flour and with the incorporation of chitosan nanoparticles loaded with antioxidants.

The Development of Novel Edible Films from Single-Cell Protein Produced by the Biotechnological Valorization of Cheese Whey

The production of value-added products from microorganisms, such as single-cell protein (SCP), through the valorization of agricultural byproducts enhances circular economy while offering alternative solutions for waste treatment. In this study, SCP was obtained through the biotechnological treatment and valorization of cheese whey, the main byproduct of the dairy industry, for the development of novel edible films. To the best of the authors’ knowledge, this is the first report examining SCP as a biopolymer for edible film production. Specifically, Kluyveromyces marxianus, which has gained QPS and GRAS status, strain EXF-5288 cultivated in deproteinized cheese whey (DCW) lactose (10.0 g/L) in a 3 L fed-batch bioreactor, resulting in a SCPmax of 2.63 g/L with a protein content of up to 49.1% w/w. The addition of increased glycerol concentrations (30, 40, and 50% w/w of dry cells) as plasticizers was examined to develop SCP-based edible films. Regarding physicochemical characterization, increased glycerol concentration significantly increased moisture content (MC%) and solubility (S%), but there was not a significant difference in other parameters. Regarding wettability, SCP-based films could be described as oleophilic surfaces since the degree of oil contact angle (OCA) ranged between 46.7° ± 1.3 and 54.0° ± 0.5. The proposed holistic approach could contribute to the development of sustainable packaging materials through waste treatment.

Effect of glycerol plasticizer on the structure and characteristics of bacterial cellulose-based biocomposite films

Abstract Biocomposite film was successfully produced by combining bacterial cellulose (BC) and sodium alginate (ratio of 80:20) with the addition of glycerol as conventional plasticizer at varied concentration (2, 4, 6% w/w, based on total sample weight) through solution casting method. The influence of glycerol content on structure (by FTIR), mechanical properties, optical properties (by colorimeter and spectrophotometer) and water vapor permeability (WVP, gravimetric method) of BC biocomposite film was investigated. The addition of glycerol disrupts the inter- and intramolecular hydrogen bonds in the cellulose chains, replaced by weaker BC-alginate-glycerol bonds. This resulted a decrease in film density, causing lower tensile strength, lightness, opacity and WVP of BC biocomposite film. An increase in glycerol concentration led to an increase in elongation percentage due to the effect of glycerol plasticization. Film with 4% glycerol exhibited the lowest WVP (5.08x10-13 g/m.s.Pa), highest lightness (L = 73.49), lowest opacity (3.24 Abs/mm) with tensile strength of 19.57 MPa and elongation 8.38%. The addition of glycerol significantly affects the BC biocomposite film properties. The resulting biofilm shows performance equivalent to commercial bioplastic TeloRoll.

Sorghum starch: Extraction, characterization and film development

Sorghum starch was extracted from sorghum grain (24.27 % average yield) and had a high carbohydrate content (86.66 %), indicating its high purity. This starch was used for the production of films with different concentrations of sorghum starch (2, 3 and 4 %) and glycerol (20, 30 and 40 g/100 g of starch). Most films were homogeneous and practically amorphous; however, the micrographs revealed the presence of some starch granules. These films also had relevant barrier properties to ultraviolet light, with infrared spectrum characteristic of sorghum starch, high lightness (L* = 87.77–90.19) and a tendency of color for the pink, but with low intensity of hue (h° = 297.06–315.20; chroma = 7.00–9.47). Thickness varied from 0.048 to 0.081 mm and the water solubility from 27 % to 48 %. Thermogravimetric analysis revealed the existence of three thermal events, correspondents to the elimination of water, decomposition of glycerol and starch, respectively. The glass transition temperature decreased with increasing glycerol content, keeping in range of 9–15°C. The film with the best mechanical performance was the one composed of 4 % starch and 30 g/100 g glycerol, as it presented a tensile strength of 3.63 MPa and elongation of 44.10 %. Water vapor permeability varied from 5.504 a 14.234 g.mm.m−2.dia−1.kPa−1, due to the increase in the concentrations of starch and glycerol. The characterization directed the usage of such films to pack vegetables and, therefore, proved that the sorghum starch is a promising source for the production of biodegradable films.

Effect of different proportions of glycerol and D-mannitol as plasticizer on the properties of extruded corn starch.

In this study, thermoplastic starch (TPS) was prepared by melt extrusion process, in which glycerol and/or D-mannitol were used as plasticizers, and the effect of different glycerol/D-mannitol ratios (4:0, 3:1, 2:2, 1:3, and 0:4) on the physicochemical properties of the extruded starch samples was investigated. The short-range molecular order, crystallization, gelatinization, thermal stability, and thermal properties of the TPS samples were analyzed through attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), rapid visco analysis (RVA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The results showed that the crystallinity and short-range molecular order of the TPS samples increased with increasing glycerol content. Conversely, the water absorption index (WAI) and water solubility index (WSI) of the TPS samples decreased with increasing glycerol content. In addition, the TPS samples with higher glycerol content exhibited higher gel and thermal stabilities. This study provides a theoretical basis for starch extrusion and plasticization in the preparation of TPS-based materials with specific properties.

The strengthening mechanism of mechanical performance for polyurethanes with micro-content crosslinkers

Chemical crosslinking is one widely used method to endow polyurethane (PU) with desirable properties. However, the introduction of crosslinkers in PU elastomers can often lead to the destruction of phase separation, resulting in weakened mechanical properties. Herein, a series of PUs with micro-content crosslinker were synthesized from poly(oxytetramethylene) glycol (PTMG), diphenylmethane-4,4′-diisocyanate (MDI), and chain extender of butane-1,4-diol (BDO) containing varied amounts of glycerol. The phase separation of PUs decreases with increased glycerol content, while the tensile strength increases. To elucidate this enhancement in mechanical properties, morphology investigation with capability of direct observation of components distribution is employed. An increased thickness of interphase between the domain of hard segment (HS) and soft segment (SS) is observed, which indicates that more HS is moved to the interphase upon the introduction of glycerol. The results of electron energy loss spectroscopy (EELS) further disclosed that glycerol formed aggregations located at the interphase. These aggregations increase the crosslinking density of the interphase, which strengthens HS domains and prevents them from being destroyed under tension, thereby increasing the tensile strength. It is the first time of disclosing distribution feature of micro-content crosslinker of PU as well its strengthening mechanism in tensile strength, which could assist in developing PU with desirable mechanical properties.

Antifungal mechanism of Angelica sinensis essential oil against Penicillium roqueforti and its application in extending the shelf life of bread

There are a variety of reports on the application of Angelica sinensis essential oil (ASEO) in the biomedical field. However, the antifungal mechanism of ASEO has not been reported. In this study, the antifungal mechanism of ASEO against Penicillium roqueforti was investigated by proteomics and genomics. ASEO can increase the permeability of P. roqueforti cell membrane and decrease the content of lipid and trehalose. With the increase of glycerol content, the HOG signaling pathway can be upregulated. Consistent with the above phenotypic changes, proteomics confirmed that ASEO treatment inhibited the steroid synthesis pathway of P. roqueforti. The significant down-regulation of ERG4, ERG6, ERG25, SMT1, and FDFT1 gene expression confirmed this conclusion. Cluster+activates the MAPK and UPP signaling pathways and ultimately leads to cell apoptosis. The bread shelf life experiment showed that ASEO could extend the shelf life of bread up to day 7. This study provides new evidence for the antifungal activity of ASEO against P. roqueforti and will promote the use of ASEO in the preservation of food and agricultural products.

Effect of film properties on droplet impact on suspended films

Understanding the dynamics and underlying mechanisms of droplet impact on suspended films is crucial for controlling droplet motion. In this study, we conducted experiments to investigate droplet impact on suspended films and examined the typical phenomena and corresponding Weber number domains. We explored the effects of changing sodium dodecyl sulfate (SDS) concentration and glycerol content on the surface tension and dynamic viscosity of the films. Additionally, we elucidated the characteristics of film deformation and droplet trajectory. An energy analysis was performed, considering the droplet kinetic energy (Ek0), surface energy increment of the film (ΔEfs), and viscous dissipation (Evis). The results demonstrate that as the SDS concentration increases, the upper critical Weber number (Wecru) between bouncing and passing decreases, while the lower critical Weber number (Wecrl) between coalescence and bouncing first decreases and then increases. For droplet bouncing, increasing the SDS concentration makes the films more susceptible to deformation, whereas increasing the glycerol content enhances film rigidity. Moreover, increasing the SDS concentration and glycerol content leads to higher energy losses, resulting in a reduction in the maximum bouncing height (hbdmax). Regarding droplet passing, the passing velocity (Vpd) increases with increasing SDS concentration. For films without SDS, Vpd increases with increasing glycerol content, while for films with SDS, Vpd decreases. The different impact modes are categorized based on the dimensionless energy parameter E* = Ek0/(ΔEfs + Evis). We have successfully predicted the critical height thresholds (Hd0crl and Hd0cru) and established a relationship of We* = f (Re*, Bo*) that aligns well with experimental results.

Effect of glycerol concentration on levels of toxicants emissions from water-pipe tobacco smoking (WTS)

Glycerol, flavorings and sweeteners constitute approximately 70% of water-pipe tobacco smoking (WTS) mixtures. Tobacco mixture combustion produces smoke toxins (e.g. carbonyl compounds), of which the type and amount are highly dependable on tobacco mixture formula. While glycerol in tobacco mixture contribute to enhanced smoking experience, its’ combustion produces toxicants such as acrolein. According to WHO, there are no approved international upper limits regulations on WTS ingredients. This study aims to assess toxicant emission levels corresponding to increasing glycerol concentration in WTS mixtures, which may aid in developing tobacco regulations towards harm reduction.MethodsLaboratory experimental study. Using laboratory water-pipe smoking machine, levels of toxicant emissions in the smoke from WTS mixture samples containing varying glycerol concentrations were measured using High-performance Liquid Chromatography (HPLC). Smoke from 5 consecutive smoking cycles with 35 puffs each (ISO 22486 standard) was led through a trapping system as described in the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) recommended method No. 74 (Determination of selected carbonyls in mainstream cigarette smoke by HPLC). Trapped carbonyls were then analysed by HPLC with a DAD detector.ResultsAcrolein emission is associated with glycerol addition in WTS mixture indicated by lab-made samples throughout all glycerol concentrations (10%, 20%, 40% and 60%), and brand samples with glycerol concentrations 10% to 20%. However, brand samples showed no increase in acrolein emission corresponding to the increase in glycerol concentrations from 20% to 60%.ConclusionThe effect of glycerol addition in waterpipe tobacco on acrolein emission varies between products. Tobacco fillers, additives and contents quality and other factors may affect toxicant emission levels. Therefore, regulatory recommendations towards defining upper limits of content concentrations require further investigations regarding potential confounders in acrolein emissions and health effects of market-available glycerol concentrations in waterpipe tobacco smoking.

A terpyridyl functionalized rhodamine dye for viscosity sensing with fluorescence enhancement and mitochondria-targeting imaging

Exploring new fluorescent organic dyes with mitochondria-targeted and viscosity-sensitive functions attracts extensive attention because they may provide access to a better understanding of the microenvironments of the subcellular level via biological imaging. Herein a terpyridyl functionalized rhodamine dye (TRMe) has been facilely designed and prepared, which shows a highly selective fluorescence enhancement response to viscosity (1.0–1238.0 cp) in water-glycerol mixtures with the increased glycerol content. In addition, TRMe can respond to viscosity enhancement over a wide pH range (1.0–10.0) and presents low cell toxicity. Besides, a good linearity between the viscosity and fluorescence lifetime of TRMe can be observed. Significantly, TRMe shows excellent mitochondria-targeted performance with a Pearson's colocalization coefficient of 0.958 and can be employed as a tracer for viscosity imaging in Nystatin-stimulated living HeLa cells.

Development of Silk Fibroin-Based Non-Crosslinking Thermosensitive Bioinks for 3D Bioprinting.

Three-dimensional (3D) bioprinting holds great promise for tissue engineering, allowing cells to thrive in a 3D environment. However, the applicability of natural polymers such as silk fibroin (SF) in 3D bioprinting faces hurdles due to limited mechanical strength and printability. SF, derived from the silkworm Bombyx mori, is emerging as a potential bioink due to its inherent physical gelling properties. However, research on inducing thermosensitive behavior in SF-based bioinks and tailoring their mechanical properties to specific tissue requirements is notably lacking. This study addresses these gaps through the development of silk fibroin-based thermosensitive bioinks (SF-TPBs). Precise modulation of gelation time and mechanical robustness is achieved by manipulating glycerol content without recourse to cross-linkers. Chemical analysis confirms β-sheet conformation in SF-TPBs independent of glycerol concentration. Increased glycerol content improves gelation kinetics and results in rheological properties suitable for 3D printing. Overall, SF-TPBs offer promising prospects for realizing the potential of 3D bioprinting using natural polymers.

Versatile hydrolyzed polyacrylamide-polyethyleneimine gels reinforced with glycerol for plugging and abandonment of oil wells

Temporary abandonment of oil wells requires isolation protocols to ensure safety of the environment and operators, for subsequent reactivation. For this, barrier materials are used to prevent influx of fluids from the rock formation to the wellbore. Polymeric gels are a promising alternative due to their ability to form a three-dimensional structure in situ with adequate elastic properties. With this goal, solid-free gels of hydrolyzed polyacrylamide and polyethyleneimine with glycerol as reinforcement material were developed. Furthermore, diethylenetriamine and diethanolamine were added to the formulations as anti-syneresis agents. The gelation kinetics and gels stability were evaluated through bottle tests and rheological measurements. The increase in glycerol content combined with DETA and DEA in the gels resulted in a reduction of gelation time varying according to the concentration of anti-syneresis agents added. This combination also enabled the increase on thermal stability of the gels with significant delay of 110% in the syneresis time. Furthermore, the storage and loss modulus and tan delta results showed that the new HPAM-PEI-Glycerol-DETA/DEA gel formulation had superior elastic properties compared to the HPAM-PEI gel.

Interfacial polymerization process based on diffusion control: Role of chemical composition and morphology on fouling resistance

Nanofiltration, as a technology with low energy consumption, no secondary pollution, and continuous and compact operation, is widely used in the fields of seawater desalination, resource recovery and reuse, and drinking water purification, etc. However, “trade-off” effect and membrane fouling are the main problems limiting the application of nanofiltration membranes. Herein, glycerol was introduced into the aqueous reactive solution in interfacial polymerization (IP) for regulating chemical composition and membrane structure simultaneously. As glycerol raised the viscosity of the reactive solution which slowing down the diffusion rate of amine monomer, crumpled structure generated by the diffusion-driven instability. At the same time, the addition of glycerol varied the oxygen content in the skin layer of the membrane. At 60% glycerol content, the as-prepared membrane achieved a pure water permeance of 21.14 L·m−2·h−1·bar−1 with sodium sulfate rejection of 95.6%. However, the oxygen content in the chemical composition of the membrane showed a minimum value with the increase of glycerol concentration indicating a competitive reaction between the amine monomer and glycerol. Through the anti-fouling analysis of membranes with different chemical compositions and structures, it was found that the increase in roughness of nanofiltration membranes with similar chemical composition resulted in an increase of irreversible pollution. The nanofiltration membrane with similar membrane structure and higher oxygen content had stronger anti-fouling ability to humic acid. It is concluded that the rational design of the crumpled membrane with high oxygen-chemical composition is expected to obtain a high flux nanofiltration membrane with anti-fouling performance.

Simultaneous Hydrogen and Ethanol Production from Crude Glycerol by a Microbial Consortium Using Fed-Batch Fermentation

Simultaneous bioproduction of hydrogen and ethanol from cheaper waste feedstock has the potential for the development of a more cost-effective biofuel generation process. Crude glycerol (CG), a by-product of the biodiesel industry, is a renewable resource, abundant, sold at low prices and available worldwide. However, the main CG limitations in fermentation processes are mainly related to the presence of impurities and the lack of nitrogen sources, both acting on microbial activity. In this study, a fermentation process with CG was improved using a highly specific microbial consortium called GlyCeroL (GCL). The process was developed in fed-batch fermentation mode using not diluted substrate and carried out under non-sterile conditions and at increasing amounts of the substrate (from 20 to 80 gL−1 of glycerol). The results showed higher H2 (from 6 to 8 LL−1) and EtOH (from 13 to 20 gL−1) production by increasing glycerol concentration from 20 to 40 gL−1. On the other hand, a decrease in glycerol degradation efficiency (from 75 to 56%) was observed. Then, the nitrogen sparging strategy was applied. Using CG of 40 gL−1, process improvement was achieved, leading to the increased production of hydrogen (10 LL−1) but not that of ethanol (20 gL−1). A further increase to 60 gL−1 of glycerol produced a slight increment of EtOH (21 gL−1) and H2 (11 gL−1) but a sharp decrease in glycerol degradation efficiency (41%). Acetate, as the main impurity of CG, was an additional carbon source for GCL microorganisms contributing to EtOH production and increasing that of lactic acid to restore the redox balance. The Denaturing Gradient Gel Electrophoresis (DGGE) fingerprint at the end of all fed-batch fermentations supported the robustness of GCL functional units and their adaptability to fermentation conditions.

Toward a Circular Bioeconomy: Exploring Pineapple Stem Starch Film as Protective Coating for Fruits and Vegetables.

In order to reduce our dependence on nonrenewable plastics and solve the problem of non-biodegradable plastic waste, there has been much attention paid to the development of biodegradable plastics from natural resources. Starch-based materials have been widely studied and developed for commercial production, primarily from corn and tapioca. However, the use of these starches could generate food security problems. Therefore, the use of alternative starch sources, such as agricultural waste, would be of great interest. In this work, we investigated the properties of films prepared from pineapple stem starch, which has a high amylose content. Pineapple stem starch (PSS) films and glycerol-plasticized PSS films were prepared and characterized using X-ray diffraction and water contact angle measurements. All films exhibited some degree of crystallinity, making them water-resistant. The effect of glycerol content on mechanical properties and gas (oxygen, carbon dioxide and water vapor) transmission rates was also studied. The tensile modulus and tensile strength of the films decreased with increasing glycerol content, while gas transmission rates increased. Preliminary studies showed that coatings made from PSS films could slow down the ripening process of bananas and extend their shelf life.

Rapid wetting of shear-thinning fluids

By studying the spreading behavior of aqueous glycerol and polymer solutions on smooth surfaces, we found that shear-thinning solutions behave similarly to water in the initial spreading phase, while glycerol solutions show significantly slower spreading. For the glycerol solutions, an increase in glycerol concentration effectively increases the contact-line friction, resulting in increased resistance to wetting. For the polymeric solutions, however, an increase in polymer concentration does not modify contact-line friction. As a consequence, the energy dissipation at the contact line can not be controlled by varying the amount of additives for shear-thinning fluids.

Insight into the Effect of Glycerol on Dielectric Relaxation and Transport Properties of Potassium-Ion-Conducting Solid Biopolymer Electrolytes for Application in Solid-State Electrochemical Double-Layer Capacitor.

The increased interest in the transition from liquid to solid polymer electrolytes (SPEs) has driven enormous research in the area polymer electrolyte technology. Solid biopolymer electrolytes (SBEs) are a special class of SPEs that are obtained from natural polymers. Recently, SBEs have been generating much attention because they are simple, inexpensive, and environmentally friendly. In this work, SBEs based on glycerol-plasticized methylcellulose/pectin/potassium phosphate (MC/PC/K3PO4) are investigated for their potential application in an electrochemical double-layer capacitor (EDLC). The structural, electrical, thermal, dielectric, and energy moduli of the SBEs were analyzed via X-ray diffractometry (XRD), Fourier transforms infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), transference number measurement (TNM), and linear sweep voltammetry (LSV). The plasticizing effect of glycerol in the MC/PC/K3PO4/glycerol system was confirmed by the change in the intensity of the samples' FTIR absorption bands. The broadening of the XRD peaks demonstrates that the amorphous component of SBEs increases with increasing glycerol concentration, while EIS plots demonstrate an increase in ionic conductivity with increasing plasticizer content owing to the formation of charge-transfer complexes and the expansion of amorphous domains in polymer electrolytes (PEs). The sample containing 50% glycerol has a maximal ionic conductivity of about 7.5 × 10-4 scm-1, a broad potential window of 3.99 V, and a cation transference number of 0.959 at room temperature. Using the cyclic voltammetry (CV) test, the EDLC constructed from the sample with the highest conductivity revealed a capacitive characteristic. At 5 mVs-1, a leaf-shaped profile with a specific capacitance of 57.14 Fg-1 was measured based on the CV data.

Ultrafast fluorescence depolarisation in green fluorescence protein tandem dimers as hydrophobic environment sensitive probes.

Advances in ultra-fast photonics have enabled monitoring of biochemical interactions on a sub nano-second time scale. In addition, picosecond dynamics of intermolecular energy transfer in fluorescent proteins has been observed. Here, we present the development of a genetically encoded fluorescent sensor that can detect changes in hydrophobicity by monitoring ultrafast fluorescence depolarisation. Our sensor is composed of a pair of dimeric enhanced green fluorescent proteins (dEGFPs) linked by a flexible amino-acid linker. We show dimerisation is perturbed by the addition of glycerol which interferes with the hydrophobic interaction of the two proteins. Time-resolved fluorescence anisotropy revealed a systematic attenuation of ultrafast fluorescence depolarisation when the sensor was exposed to increasing glycerol concentrations. This suggests that as hydrophobicity increases, dEGFP pairing decreases within a tandem dimer. Un-pairing of the protein fluorophores dramatically alters the rate of energy transfer between the proteins, resulting in an increase in the limiting anisotropy of the sensor.