Evaluation of the benefits of plant growth-promoting rhizobacteria and mycorrhizal fungi on biochemical and morphophysiological traits of Aloe barbadensis Mill under water deficit stress.

Aloe barbadensis is a drought-tolerant perennial medicinal plant with both nutritional and cosmetic uses. Drought is one of the main abiotic stresses limiting plant growth and development. However, the use of drought-resistant plants combined with beneficial soil micro-organisms could improve the effectiveness of biological methods to mitigate drought damage. This research aims to evaluate the effects of Funneliformis mosseae (MF), plant growth-promoting rhizobacteria (PGPR) (including Pseudomonas putida and Pantoea agglomerans), and their co-inoculation on the macronutrient status, antioxidant enzyme activities, and other morphophysiological traits of A. barbadensis under four irrigation regimes [25%, 50%, 75% and 100% of water requirement (WR)]. Three harvests were conducted, revealing that inoculation enhanced the survival rate and shoot fresh weight (SFW) compared to the control plants. However, at 25% WR, the SFW was reduced by 43% more than the control. across all harvests, while the PGPR + MF treatment showed increases of more than 19%, 11%, and 17% compared to the control, MF, and PGPR treatments, respectively. The results also showed that A. barbadensis exhibited innate drought tolerance up to a 50% WR level by enhancing physiological defenses, such as antioxidant enzyme activity. Inoculation increased the macronutrient status of the plant at all levels of irrigation regimes especially under severe drought conditions. The highest levels of nitrogen (N) (16.24 mg g-1 DW) and phosphorus (P) (11.29 mg g-1 DW) were observed in the PGPR + MF treatment at 100% WR. The maximum relative water content under MF inoculation and 75% WR (98.24%) (98.24%) was reached. PGPR + MF treatment alleviated drought-induced osmotic stress, as indicated by reduced antioxidant enzyme activities and electrolyte leakage. However, P. putida and P. agglomerans strains alone or in combination with F. mosseae increased plant yield, macronutrient uptake and antioxidant enzyme activity. This study underscores the potential of these PGPR and MF strains as invaluable biological tools for the cultivation of A. barbadensis in regions with severe drought stress.

Biological activity of essential oils from Ferulago angulata and Ferula assa-foetida against food-related microorganisms (antimicrobial) and Ephestia kuehniella as a storage pest (insecticidal); an in vitro and in silico study.

Misuse of synthetic pesticides and antimicrobials in agriculture and the food industry has resulted in food contamination, promoting resistant pests and pathogen strains and hazards for humanity and the environment. Therefore, ever-increasing concern about synthetic chemicals has stimulated interest in eco-friendly compounds. Ferulago angulata (Schltdl.) Boiss. and Ferula assa-foetida L., as medicinal species with restricted natural distribution and unknown biological potential, aimed at investigation of their essential oil (EO) biological properties, were subjected. Z-ß-Ocimene and Z-1-Propenyl-sec-butyl disulfide molecules were identified as the major composition of the essential oil of the fruits of F. angulata and F. assa-foetida, respectively. In vitro antimicrobial activity and membrane destruction investigation by scanning electron microscopy imaging illustrated that F. angulata EO had potent antibacterial activity. Besides, the EOs of both plants exhibited significant anti-yeast activity against Candida albicans. In relation to insecticidal activity, both EOs indicated appropriate potential against Ephestia kuehniella; however, the F. assa-foetida EO had more toxicity on the studied pest. Among several insecticidal-related targets, acetylcholinesterase was identified as the main target of EO based on the molecular docking approach. Hence, in line with in vitro results, in silico evaluation determined that F. assa-foetida has a higher potential for inhibiting acetylcholinesterase and, consequently, better insecticide properties. Overall, in addition to the antioxidant properties of both EO, F. angulata EO could serve as an effective prevention against microbial spoilage and foodborne pathogens, and F. assa-foetida EO holds promise as a multi-purpose and natural biocide for yeast contamination and pest management particularly against E. kuehniella.

The comparative perspective of phytochemistry and biological properties of the Apiaceae family plants.

Despite the availability of numerous reports on the discovery of medicinal plant compounds and their properties, one may encounter contradictory results released by these reports at the level of plant families and even within species. To establish an accurate perspective of the Apiaceae family, this study examined the fruit essential oil and methanolic extract of wild and common species of this family. According to the measurement of the antioxidant property in the methanolic extract of the fruits using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, Ferula gummosa, Pimpinella anisum and Cuminum cyminum have high power in inhibiting free radicals. However, Bunium persicum had the strongest DPPH radicals inhibitory potential among all essential oils. The results of antimicrobial tests and their classification analysis showed that C. cyminum and B. persicum fruit essential oil with a high amount of cuminaldehyde had the most antibacterial properties. At the same time, the antifungal properties of H. persicum essential oil (rich in aliphatic ester) were stronger than those of the all the studied plants. Also, the essential oils of F. gummosa and Kelussia odoratissima had favourable antimicrobial properties compared to other studied plants. The investigation of the bacterial structure by scanning electron microscope confirmed the effect of the applied essential oils dose and their antibacterial potential. In general, for the first time, this paper determined the biological values of the fruit essential oil of some wild plants, such as K. odoratissima and H. persicum. Besides, in vitro examination and the mathematical models provided a suitable classification, which makes a comprehensive view in terms of the properties of the Apiaceae family.

Cellulose-based composite scaffolds for bone tissue engineering and localized drug delivery.

Natural bone constitutes a complex and organized structure of organic and inorganic components with limited ability to regenerate and restore injured tissues, especially in large bone defects. To improve the reconstruction of the damaged bones, tissue engineering has been introduced as a promising alternative approach to the conventional therapeutic methods including surgical interventions using allograft and autograft implants. Bioengineered composite scaffolds consisting of multifunctional biomaterials in combination with the cells and bioactive therapeutic agents have great promise for bone repair and regeneration. Cellulose and its derivatives are renewable and biodegradable natural polymers that have shown promising potential in bone tissue engineering applications. Cellulose-based scaffolds possess numerous advantages attributed to their excellent properties of non-toxicity, biocompatibility, biodegradability, availability through renewable resources, and the low cost of preparation and processing. Furthermore, cellulose and its derivatives have been extensively used for delivering growth factors and antibiotics directly to the site of the impaired bone tissue to promote tissue repair. This review focuses on the various classifications of cellulose-based composite scaffolds utilized in localized bone drug delivery systems and bone regeneration, including cellulose-organic composites, cellulose-inorganic composites, cellulose-organic/inorganic composites. We will also highlight the physicochemical, mechanical, and biological properties of the different cellulose-based scaffolds for bone tissue engineering applications.

Improvement of biochemical and antioxidant responses of borage (Borago officinalis L.) under drought stress conditions with the use of vermicompost and zinc sulfate.

Drought poses a significant threat to crop production systems. Therefore, this study aimed to investigate the impact of vermicompost and foliar application of zinc sulfate under conditions of reduced irrigation on the physiological properties of Borage. A two-year experiment was conducted following a split factorial design within a randomized complete block design with three replications at Yasouj University Research Station in 2017 and 2018. The primary factor involved three levels of irrigation cut-off (I1: full irrigation, I2: irrigation cut-off at the flowering stage, and I3: irrigation cut-off during the seed-filling stage). The sub-factor included vermicompost fertilizer at three different levels (N0: control, N1: 5 ton ha-1, and N2: 10 ton ha-1), and foliar application of zinc sulfate at three levels (Z0: control, Z1: 2 and Z2: 4 mg l-1). During the flowering stage stress, foliar application of 4 mg l-1 of zinc sulfate resulted in an increased chlorophyll a + b content in plants (2.91 mg g-1 FW), while the control showed the lowest amount (2.56 mg g-1 FW). Vermicompost supplementation improved chlorophyll a + b content during the seed-filling stage under conditions of irrigation cut-off. The results indicated that an increase in vermicompost fertilizer application led to an elevation in relative water content (RWC), with the highest RWC (79.2%) achieved when 10 ton ha-1 of vermicompost was applied. Irrigation cut-off during the seed-filling stage resulted in increased electrolyte leakage and higher fertilizer usage, thus reducing cell damage. Furthermore, the findings revealed that applying 2 and 4 mg l-1 zinc sulfate reduced malondialdehyde content by 5% and 9%, respectively. The catalase, peroxidase, and superoxide dismutase activities demonstrated an increased response to stress mitigation treatments. However, their activities decreased as vermicompost and zinc sulfate levels increased. The study demonstrated that the highest biomass was obtained when 10 ton ha-1 of vermicompost and 2 mg l-1 of zinc sulfate were applied. The flowering stage of the plant exhibited the most significant negative impact under stress conditions. Nonetheless, using vermicompost and zinc sulfate, particularly during the seed-filling phase, alleviated the adverse effects of drought stress. In conclusion, our findings indicate that, although drought stress resulted in increased electrolyte leakage due to elevated free radical production, vermicompost, and zinc sulfate played a role in reducing stress.

Bioprinted Membranes for Corneal Tissue Engineering: A Review.

Corneal transplantation is considered a convenient strategy for various types of corneal disease needs. Even though it has been applied as a suitable solution for most corneal disorders, patients still face several issues due to a lack of healthy donor corneas, and rejection is another unknown risk of corneal transplant tissue. Corneal tissue engineering (CTE) has gained significant consideration as an efficient approach to developing tissue-engineered scaffolds for corneal healing and regeneration. Several approaches are tested to develop a substrate with equal transmittance and mechanical properties to improve the regeneration of cornea tissue. In this regard, bioprinted scaffolds have recently received sufficient attention in simulating corneal structure, owing to their spectacular spatial control which produces a three-cell-loaded-dimensional corneal structure. In this review, the anatomy and function of different layers of corneal tissue are highlighted, and then the potential of the 3D bioprinting technique for promoting corneal regeneration is also discussed.

Efficacy of biological agents and fillers seed coating in improving drought stress in anise.

Many plants, including anise, have tiny, non-uniform seeds with low and light nutrient reserves. The seeds also show a weak establishment, especially under stressful conditions where their accurate planting in the soil and optimal yield are tough. This study sought to improve anise seeds' physical and physiological characteristics under drought stress. To this end, two factorial experiments under laboratory and greenhouse conditions were performed in a completely randomized design with 4 and 3 replications, respectively. Five levels of seed inoculation (inoculation with T36 and T43 of Trichoderma harzianum, and CHA0 and B52 of Pseudomonas fluorescent, and non-inoculation which means that control seeds were not treated with microbial inoculant), three levels of coating (K10P20, K10P10V5, and non-coating), and three levels of drought stress (0, -3, and -6 bars) were considered as the factorial experiment [vermiculite (V), kaolin (K), and perlite (P) numbers refer to the amount of material used in grams]. The laboratory experiment revealed that the combined treatments of bio-agents with coating increased the physical and germination characteristics of anise seeds compared to the control treatment. The greenhouse experiment showed that drought stress reduced the initial growth indices. Still, the combination treatments of biological agents and coating (fillers) could alleviate the destructive effects of drought stress to some extent and improve these indices. The best treatment was provided by T36 and K10P20 in both experiments, which significantly increased morphological indices.

Promoting keratocyte stem like cell proliferation and differentiation by aligned polycaprolactone-silk fibroin fibers containing Aloe vera.

There is a long history behind applying biological macromolecules like Aloe vera (AV) in regenerative medicine; endowed with anti-inflammatory and antimicrobial activities besides improving immune activity, AV has always been of particular interest to regenerate/reconstruct injuries and burns. In the present study, aligned electrospun polycaprolactone (PCL)-silk fibroin (SF) fibers containing different percentages of AV (0, 2.5, 5, and 7.5%wt) were fabricated for stromal regeneration. The results illustrated that a uniform bead-free structure was obtained, and the AV incorporation decreased the mean fiber diameter from 552 down to 182 nm and led to more alignment in the fibers. The Young's modulus raised from 4.96 to 5.26 MPa by higher amount of AV up to 5%wt. It is noteworthy that both the fiber alignment and AV affected the scaffolds' transparency and water uptake to increase. The human stromal keratocyte cells (hSKC)s culture revealed that the addition of AV and morphological properties of scaffolds encouraged cell adhesion and proliferation. The mRNA expression level for keratocan and ALDH3A1 and immunocytochemistry F-actin revealed the positive effect of AV on hSKCs differentiation. Our study indicated the promising potential of AV as a biological macromolecule for stromal tissue regeneration.

PEG-mesoporous material modified by superparamagnetic nanoparticles as a delivery system of cefotaxime.

The fight against infectious bacterial diseases has been taking major steps forward by designing new nanodrugs and nanoscale biological carriers with unique physicochemical properties. Here, polyethylene glycol (PEG)-silica mesoporous material/superparamagnetic CuFe2O4 nanoparticle nanocomposite was synthesized using a facile chemical approach, and proposed as a carrier for the delivery of cefotaxime (CTX) drug. The resulting nanocomposite material and nanocomposite CTX drug carrier were characterized by different techniques. Antibacterial activity of the nanocomposite drug carrier was investigated against E.coli and S. aureus bacteria, and compared with that of commercial CTX drug. It was found that the minimum inhibitory concentrations of the nanocomposite drug carrier (1.25 and 5 µg/mL) were significantly less than those of the commercial drug (10 and 80 µg/mL) against the bacteria. Furthermore, enhanced performance of the nanocomposite CTX carrier for both the Gram-negative and Gram-positive bacteria was evidenced.

Biochemical response and nutrient uptake of two arbuscular mycorrhiza-inoculated chamomile varieties under different osmotic stresses.

BACKGROUND: Water-deficit stress is known as one of the most severe environmental stresses affecting the growth of plants through marked reduction of water uptake, which leads to osmotic stress by lowering water potential. Adopting appropriate varieties using soil microorganisms, such as arbuscular mycorrhiza (AM) fungi, can significantly reduce the adverse effects of water deficiency. This study aimed to evaluate the role of Funneliformis mosseae on nutrient uptake and certain physiological traits of two chamomile varieties, namely Bodgold (Bod) and Soroksári (Sor) under osmotic stress. For pot culture, a factorial experiment was performed in a completely randomized design with three factors: osmotic stress (PEG 6000) was applied along with Hoagland solution at three levels (0, -0.4 and -0.8 MPa), two German chamomile varieties (Bodgold (Bod) and Soroksari (Sor)), and AM inoculation (Funneliformis mosseae species (fungal and non-fungal)) at four replications in perlite substrate. RESULTS: Osmotic stress significantly reduced the uptake of macro-nutrients (N and P) and micro-nutrients (Fe, Cu, Mn, and Zn) in the shoots and roots. Moreover, the level of osmolytes (total soluble sugars and proline) and the activity of antioxidant enzymes in the shoots of both varieties increased under osmotic stress. Regarding the Sor variety, the level of these compounds was more satisfactory. AM improved plant nutrition uptake and osmolyte contents while enhancing antioxidant enzymes and reducing the adverse effects of osmotic stress. Under osmotic stress, the growth and total dry weight were improved upon AM inoculation. CONCLUSIONS: In general, inoculation of chamomile with AM balanced the uptake of nutrients and increased the level of osmolytes and antioxidant enzymes; hence, it improved plant characteristics under osmotic stress in both varieties. However, it was found to be more effective in reducing stress damages in the Sor variety.

Zn-substituted Mg2SiO4 nanoparticles-incorporated PCL-silk fibroin composite scaffold: A multifunctional platform towards bone tissue regeneration.

Electrospun porous bone scaffolds are known to imitate the extracellular matrix very well and provide an environment through which the tissue formation is enhanced. Although polymeric scaffolds have a great potential in bone tissue regeneration, their weak bioactivity (bone bonding ability) and mechanical properties have left room for improvement. Therefore, the present study focused on the developing a ternary multifunctional platform composed of polycaprolactone (PCL)/silk fibroin (SF)/Zn-substituted Mg2SiO4 nanoparticles for bone tissue regeneration. This study is composed of two connected sections including synthesis and characterization of Mg(2-x)ZnxSiO4, x = 0, 0.5, 1, 1.5, 2 through surfactant-assisted sol-gel technique followed by incorporation of the nanoparticles into PCL/SF hybrid scaffold via electrospinning technique. The weight ratios of polymers and ceramic nanoparticles were optimized to reach desirable textural-porosity, pore size, and fiber diameter-and mechanical properties. Having optimized the ternary scaffold, it was then undergone different physical, chemical, and biological tests in vitro. A precise comparison study between the ternary (PCL/SF/ceramic nanoparticles), binary (PCL/SF), and pure PCL was made to shed light on the effect of each composition on the applicability of ternary scaffold. The overall results confirmed that the Mg1Zn1SiO4 nanoparticles-incorporated PCL/SF scaffold with fluorescence property was the one yielding the highest Young's modulus and desirable textural properties. The ternary scaffold showed improved biological properties making it a promising candidate for further studies towards bone tissue regeneration.

Corneal stromal regeneration by hybrid oriented poly (ε-caprolactone)/lyophilized silk fibroin electrospun scaffold.

Applying biological macromolecule like silk fibroin (SF) is a promising material for corneal tissue engineering. However, designing an appropriate tissue-like construct to compensate the shortages of traditional routes are still challenging. SF besides possessing biocompatibility and transparency, the biomaterial should be mechanically strong. In the present study, a hybrid scaffold composed of poly-ε-caprolactone (PCL)-silk fibroin (SF) is fabricated through electro spinning technique. The aligned and non-aligned PCL-SF scaffolds with various weight ratios are fabricated. The results reveal that the addition of SF yields the scaffolds with more uniform and aligned structure. The ultimate tensile strength and Young's modulus of aligned and non-aligned PCL-SF (60:40 and 50:50) fibers are in an acceptable range for cornea applications. It is noteworthy that the aligned PCL-SF (60:40 and 50:50) scaffolds have more transparency, hydrophilicity, water uptake, and in vitro degradation rate than the other scaffolds. The cell compatibility results show that human stromal keratocyte cells are attached and proliferated on the aligned and non-aligned PCL-SF scaffolds. The overall results recommend that PCL-SF (60:40 and 50:50) scaffolds have a great potential for human corneal stromal regeneration.

Realization of high-efficiency fluorescent organic light-emitting diodes with low driving voltage.

It is commonly accepted that a full bandgap voltage is required to achieving efficient electroluminescence (EL) in organic light-emitting diodes. In this work, we demonstrated organic molecules with a large singlet-triplet splitting can achieve efficient EL at voltages below the bandgap voltage. The EL originates from delayed fluorescence due to triplet fusion. Finally, in spite of a lower quantum efficiency, a blue fluorescent organic light-emitting diode having a power efficiency higher than some of the best thermally activated delayed fluorescent and phosphorescent blue organic light-emitting diodes is demonstrated. The current findings suggest that leveraging triplet fusion from purely organic molecules in organic light-emitting diode materials offers an alternative route to achieve stable and high efficiency blue organic light-emitting diodes.

Physiological and yield responses of purple coneflower (Echinacea purpurea (L.) Moench) to nitrogen sources at different levels of irrigation.

Echinacea purpurea (L.) is one of the most important medicinal plants in the world showing different biochemical reactions as affected by drought stress and nitrogen fertilizer. The purpose of this study was to determine the effect of nitrogen on soluble protein, enzyme activities, carotenoids metabolism, greenness and biological yield of the Echinacea purpurea under different levels of irrigation. The experiment was conducted in a research field in Iran during 2013-2015. Irrigation treatments included irrigation after 25, 50 and 75% soil water depletion, and nitrogen sources were no nitrogen (N), nitroxin, 40 kg N ha-1, 40 kg N ha-1 + nitroxin and 80 kg N ha-1. Nitroxin is a biofertilizer including Azotobacter and Azospirillum. The activity of catalase (11.9-21.3 mmol g-1fw min-1), peroxidase (40.1-48.9 µmol g-1fw min-1), polyphenoloxidase (0.79-3.63 mmol g-1fw min-1) increased in both years under drought stress conditions. The lowest greenness (50.1-45.9) was achieved from no-application of nitrogen in the irrigation treatment after 75% water depletion. The results demonstrated the beneficial effects of nitrogen sources on physiological reactions, especially peroxidase, polyphenol oxidase and carotenoids metabolism. It is concluded that irrigation of E. purpurea based on 50% water depletion and 80 kg nitrogen as well as the combination of nitroxin and 40 kg nitrogen treatments should be an appropriate choice for 2 years.

Growth and nutrient content of Echinacea purpurea as affected by the combination of phosphorus with arbuscular mycorrhizal fungus and Pseudomonas florescent bacterium under different irrigation regimes.

The excessive use of chemical fertilizers has caused many environmental problems and threatens the health of the human communities at the global level. However, the use of some beneficial soil microorganisms in addition to supplying nutrients to plants helps protect the environment. In order to achieve this goal, the effects of different irrigation regimes and application of phosphorus (P) fertilizer, with mycorrhizal arbuscular fungus (AMF) or Pseudomonas fluorescens bacterium (PFB), were studied on the growth and nutrients of Echinacea purpurea. The main factor included soil irrigation after 25, 50 and 75% of soil moisture depletion and a sub-factor of P supplied in six levels (100% chemical P, 50% P + AMF, AMF, 50% P + PFB, PFB and a control test without P fertilizer). Results showed that an increase in drought intensity reduced the absorption of nutrients and relative water content (RWC), while ion leakage increased in the leaf of E. purpurea. The AMF had a more clear effect on the N, Cu, Mn, and Fe, but PFB was more effective in an increase of Zn. With the use of PFB in the second harvest, the amount of leaf and root Zn was increased by 30.39% and 31.88%, respectively. Although 100% chemical P could increase more P concentration in the root, the combination of P fertilizer with AMF transferred more P from root to leaf. In the first and second harvest, a combination of P with PFB respectively increased the plant biological yield by 10.77% and 17.33% as compared to control. Vegetative traits, Mn, and Zn illustrated a significant increase in the second harvest. Finally, the results showed successful coexistence of bio-fertilizers with E. purpurea in increasing the content of nutrients, improving water absorption, and reducing the adverse effects of drought stress.

Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (2016 Biomed. Mater. 11 025003).

The manuscript 'Efficient decellularization of whole porcine kidneys improves reseeded cell behavior' (Poornejad et al 2016 Biomedical Materials 11: 025003) describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. A published erratum pertaining to this issue has been published (Caralt et al 2017 American Journal of Transplantation 17: 1429). Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound.

Increased Exciton Delocalization of Polymer upon Blending with Fullerene.

Interfaces between donor and acceptor in a polymer solar cell play a crucial role in exciton dissociation and charge photogeneration. While the importance of charge transfer (CT) excitons for free carrier generation is intensively studied, the effect of blending on the nature of the polymer excitons in relation to the blend nanomorphology remains largely unexplored. In this work, electroabsorption (EA) spectroscopy is used to study the excited-state polarizability of polymer excitons in several polymer:fullerene blend systems, and it is found that excited-state polarizability of polymer excitons in the blends is a strong function of blend nanomorphology. The increase in excited-state polarizability with decreased domain size indicates that intermixing of states at the interface between the donor polymers and fullerene increases the exciton delocalization, resulting in an increase in exciton dissociation efficiency. This conclusion is further supported by transient absorption spectroscopy and time-resolved photoluminescence measurements, along with the results from time-dependent density functional theory calculations. These findings indicate that polymer excited-state polarizability is a key parameter for efficient free carrier generation and should be considered in the design and development of high-performance polymer solar cells.

Biosensing estrogenic endocrine disruptors in human blood and urine: A RAPID cell-free protein synthesis approach.

Many diseases and disorders are linked to exposure to endocrine disrupting chemicals (EDCs) that mimic the function of natural estrogen hormones. Here we present a Rapid Adaptable Portable In-vitro Detection biosensor platform (RAPID) for detecting chemicals that interact with the human estrogen receptor ß (hERß). This biosensor consists of an allosteric fusion protein, which is expressed using cell-free protein synthesis technology and is directly assayed by a colorimetric response. The resultant biosensor successfully detected known EDCs of hERß (BPA, E2, and DPN) at similar or better detection range than an analogous cell-based biosensor, but in a fraction of time. We also engineered cell-free protein synthesis reactions with RNAse inhibitors to increase production yields in the presence of human blood and urine. The RAPID biosensor successfully detects EDCs in these human samples in the presence of RNAse inhibitors. Engineered cell-free protein synthesis facilitates the use of protein biosensors in complex sample matrices without cumbersome protein purification.

Manipulating Refractive Index in Organic Light-Emitting Diodes.

In a conventional organic light-emitting diode (OLED), only a fraction of light can escape to the glass substrate and air. Most radiation is lost to two major channels: waveguide modes and surface plasmon polaritons. It is known that reducing the refractive indices of the constituent layers in an OLED can enhance light extraction. Among all of the layers, the refractive index of the electron transport layer (ETL) has the largest impact on light extraction because it is the layer adjacent to the metallic cathode. Oblique angle deposition (OAD) provides a way to manipulate the refractive index of a thin film by creating an ordered columnar void structure. In this work, using OAD, the refractive index of tris(8-hydroxyquinoline)aluminum (Alq3) can be tuned from 1.75 to 1.45. With this low-index ETL deposited by OAD, the resulting phosphorescent OLED shows nearly 30% increase in light extraction efficiency.