Design and Characterization of Corn Starch Edible Films Including Beeswax and Natural Antimicrobials

The effectiveness of edible films (EFs) used as coatings to maintain the quality and safety of fresh produce for long time depends on their functional properties characterization. This study was aimed to design and evaluate physicochemical, barrier, mechanical, and antimicrobial properties of EFs based on corn starch (acetylated cross-linked (ACLS) or oxidized (OS)), micro-emulsified beeswax (BW, 0–1 % w/w), and two natural antimicrobials (lauric arginate (LAE, 400–4000 mg/L) and natamycin (NAT, 80–800 mg/L)). EFs based on ACLS or OS made with 1 % BW microemulsion produced homogeneous EFs surface and did not show changes in thickness or opacity. Water vapor permeability (WVP, 0.57 ± 0.04 g mm m^?2 h^?1 kPa^?1 for ACLS, and 0.56 ± 0.05 g mm m^?2 h^?1 kPa^?1 for OS) was reduced; tensile strength (TS, 51.48 ± 5.92 MPa for ACLS, and 40.96 ± 4.98 MPa for OS), and elastic modulus (EM, 211.30 ± 7.85 MPa for ACLS, and 203.50 ± 5.35 MPa for OS) were decreased, whereas elongation at break (E, 4.59 ± 1.11 % for ACLS, and 4.76 ± 4.98 % for OS) increased. The additive effect showed by the combination of natural antimicrobials (2000 mg/L of LAE plus 400 mg/L of NAT) incorporated into EFs with 1 % BW completely inhibited Rhizopus stolonifer, Colletotrichum gloeosporioides, Botrytis cinerea, and Salmonella Saintpaul. These properties of corn starch EFs used as coatings represent an excellent alternative to extend the shelf life of fresh produce.     

Materials and Manufacturing Methods for EWOD Devices: Current Status and Sustainability Challenges

Electrowetting-on-dielectric (EWOD) devices have proven to be effective tools for precise microfluidic manipulation or in liquid lenses that surpass conventional solid lenses in versatility. However, the fabrication of these devices presents many challenges, such as their scalability or the growing concern on their environmental impact due to materials used in their fabrication. This review provides a comprehensive analysis of the materials currently used in the fabrication of EWOD devices and the characteristics they must meet. In addition, a discussion of future challenges in the fabrication of EWOD devices is presented, in particular the environmental problems presented by some of the materials currently in use.     

Development of Methotrexate Complexes Endowed with New Biological Properties Envisioned for Musculoskeletal Regeneration in Rheumatoid Arthritis Environments

Methotrexate (MTX) administration is the gold standard treatment for rheumatoid arthritis (RA), but its effects are limited to preventing the progression of the disease. Therefore, effective regenerative therapies for damaged tissues are still to be developed. In this regard, MTX complexes of general molecular formula M(MTX)·xH₂O, where M = Sr, Zn, or Mg, were synthesized and physicochemically characterized by TGA, XRD, NMR, ATR–FTIR, and EDAX spectroscopies. Characterization results demonstrated the coordination between the different cations and MTX via two monodentate bonds with the carboxylate groups of MTX. Cation complexation provided MTX with new bioactive properties such as increasing the deposition of glycosaminoglycans (GAGs) and alternative anti-inflammatory capacities, without compromising the immunosuppressant properties of MTX on macrophages. Lastly, these new complexes were loaded into spray-dried chitosan microparticles as a proof of concept that they can be encapsulated and further delivered in situ in RA-affected joints, envisioning them as a suitable alternative to oral MTX therapy.     

Production,partial purification and properties of β‐mannanases obtained by solid substrate fermentation of spent soluble coffee wastes and copra paste using Aspergillus oryzae and Aspergillus niger

In order to achieve a higher added value of two galactomannan‐containing wastes, copra paste and spent coffee from the soluble coffee industry (SCW), solid substrate fermentation (SSF) was used. Filamentous fungi Aspergillus oryzae and A niger were used to evaluate the feasibility of producing β‐mannanase by SSF. A 2³ factorial design was used to select the best interaction among the two fungi, the two substrates and two fermentation times. The treatment ‘A niger–copra–2.5 days’ produced a significantly higher (p < 0.05) β‐mannanase activity, having five different isoforms of the enzyme, one of which was partially purified to a specific activity of 764 U mg⁻¹ (U = nmol of mannose released per second from a galactomannan substrate). Copra paste had a higher mannose/galactose ratio (14:1) than SCW (6:1), and low oil content, which led to higher β‐mannanase production from SSF. A β‐mannanase from SSF of copra produced by A oryzae was highly purified using acetone precipitation and cation exchange and size exclusion chromatographies. This enzyme had an MW of 110 kDa, a pI between 3.5 and 4.5 and a specific activity of 1760 U mg⁻¹; purification achieved was 90.7 times. The temperature and pH for optimal activity were 40 °C and 6.0 respectively. The optimal temperature was lower and the optimal pH higher than others previously reported (produced by submerged fermentation), which could be important for viscosity reduction of concentrated coffee extract in instant coffee manufacture. Copra is an interesting alternative for β‐mannanase production, since it is readily available in Mexico; moreover, the residue after SSF has a reduced galactomannan content and may be used for monogastric animal feed. © 2000 Society of Chemical Industry     

Polypyrrole–poly(heptamethylene p,p′-bibenzoate) conducting materials. Synthesis and characterization

Polypyrrole–poly(heptamethylene p,p′-bibenzoate) conducting materials, PPy–P7MB/ClO₄, were obtained by anodic coupling of pyrrole into a polybibenzoate inert matrix, using perchlorate anions as dopant agent. P7MB is a main-chain liquid crystalline polybibenzoate with adequate mechanical properties and elastic modulus of 1.4GPa at room temperature. The method of synthesis, galvanostatic or potentiostatic electrodeposition, is responsible for differences in the PPy–P7MB/ClO₄ films electrochemical response. FTIR spectra show the complex structures of P7MB and the composite conducting material. The conductivity of PPy–P7MB/ClO₄ films maintains a relatively high value, σ = 13.74Scm^?1, in spite of the insulating effect of polybibenzoate. Film micrographs reveal the typical cauliflower morphology exhibited by polypyrrole and the evolution of film growth with time.     

Quantum Dot‐Based Thermal Spectroscopy and Imaging of Optically Trapped Microspheres and Single Cells

Laser‐induced thermal effects in optically trapped microspheres and single cells are investigated by quantum dot luminescence thermometry. Thermal spectroscopy has revealed a non‐localized temperature distribution around the trap that extends over tens of micrometers, in agreement with previous theoretical models besides identifying water absorption as the most important heating source. The experimental results of thermal loading at a variety of wavelengths reveal that an optimum trapping wavelength exists for biological applications close to 820 nm. This is corroborated by a simultaneous analysis of the spectral dependence of cellular heating and damage in human lymphocytes during optical trapping. This quantum dot luminescence thermometry demonstrates that optical trapping with 820 nm laser radiation produces minimum intracellular heating, well below the cytotoxic level (43 °C), thus, avoiding cell damage.     

Cell proliferation inhibitory and apoptosis-inducing properties of anacardic acid and lunasin in human breast cancer MDA-MB-231 cells

The combination of two or more chemopreventive agents is currently being used to achieve greater inhibitory effects on breast cancer cells. Anacardic acid and lunasin are two plant-derived compounds that have been associated with anti-carcinogenic properties. These compounds show inhibitory effects on cell proliferation and inducing properties of apoptosis in human breast cancer MDA-MB-231 cell line. Both lunasin and anacardic acid exert their effects through the modulation of expression of several genes involved in cell cycle, apoptosis and signal transduction. Their combination arrests the cell cycle in S-phase and induces apoptosis at higher levels than that observed when each compound is used individually. This combination also promotes the inhibition of ERBB2, AKT1, JUN and RAF1 signalling gene expression, whose up-regulation has been reported as responsible for breast cancer cells growth and resistance to apoptosis. Our results introduce these two compounds as a promising strategy to prevent/treat breast cancer.     

AMD-Like Substrate Causes Epithelial Mesenchymal Transition in iPSC-Derived Retinal Pigment Epithelial Cells Wild Type but Not C3-Knockout

The Bruch’s membrane (BrM) is a five-layered extracellular matrix (ECM) that supports the retinal pigment epithelium (RPE). Normal age-related changes in the BrM may lead to RPE cell damage and ultimately to the onset and progression of age-related macular degeneration (AMD), which is the most common cause of visual loss among the elderly. A role for the complement system in AMD pathology has been established, but the disease mechanisms are poorly understood, which hampers the design of efficient therapies to treat millions of patients. In an effort to identify the mechanisms that lead from normal aging to pathology, we have developed a cell-based model using complement deficient human induced pluripotent stem cell (iPSC)-derived RPE cells cultured on an AMD-like ECM that mimics BrM. The data present evidence that changes in the ECM result in loss of differentiation and promote epithelial mesenchymal transition (EMT) of healthy RPE cells. This pathological process is mediated by complement activation and involves the formation of a randomly oriented collagen meshwork that drives the dedifferentiation of the RPE monolayer. Genetic ablation of complement component 3 has a protective effect against EMT but does not prevent the abnormal deposition of collagens. These findings offer new insights into the sequence of events that initiate AMD and may guide the design of efficient therapies to treat this disease with unmet medical needs.