María Guadalupe García

Mycelium-bound composites (MBCs) are emerging fungal biomaterials whose rational design remains constrained by limited control of hyphal architecture and the absence of accessible descriptors linking biological organization to macroscopic performance. Here, MBCs were fabricated from a lignocellulosic residue using two trimitic white-rot fungi of the genus Trametes (T. sanguinea and T. villosa), enabling direct assessment of strain-dependent microstructural effects under identical processing conditions. Scanning electron microscopy (SEM)–based grayscale analysis, ATR–FTIR spectroscopy, and water sorption kinetics revealed the formation of distinct mycelial matrices on the same substrate. T. villosa developed finer, highly branched hyphal networks associated with higher stiffness and improved flexural load transfer, whereas T. sanguinea formed thicker, more intertwined hyphae, resulting in greater deformability and faster water uptake. These architectural differences were consistently reflected in chemical signatures, hydrodynamic behavior, and mechanical response. Notably, a latent viable fraction persisted after oven drying, with reactivation occurring only under nutrient-rich conditions. This hypothesis-driven study isolates the effect of hyphal architecture within the trimitic system, demonstrating that trimitic fungi do not produce equivalent materials but architecturally tunable biomaterials. Collectively, the results demonstrate that simple SEM-derived microstructural metrics, supported by complementary chemical and water sorption kinetics, can discriminate between trimitic mycelial matrices and anticipate the functional performance of MBCs, providing a practical framework for structure-guided design of fungal biomaterials

HIV pre-exposure prophylaxis (PrEP) is a highly effective biomedical prevention strategy, recommended by the World Health Organization since 2015. However,

Pectin from orange peel was extracted and cross-linked, applying different cross-linking agents to visualize any effect on its mechanical and permeation properties. Calcium chloride (II) and iron chloride (III) were the cross-linking agents. Besides, commercial pectin was also used to compare its properties with neat orange pectin. Tensile testing showed mechanical stiffness of the orange pectin matrix in the presence of cross-linking agents. Calcium ions better cross-linked the polymer matrix as shown by their highest tensile strength and elastic modulus, with moderate elongation at break. Iron ions showed a weaker cross-linking effect on the pectin matrix, improving the elastic modulus but retaining almost the same tension strength. Lower elongation at break concerning neat orange pectin was observed for cross-linked samples. Water uptake (WU) and water vapor permeation (WVP) of cross-linked samples had lower values than those of neat orange pectin. However, these results are still high compared with synthetic polymers. Finally, gas permeation assays were performed using N2, O2 and CO2 gases, according to exchangeable gases in fresh fruits and vegetable packaging. Results showed a conveniently modified atmosphere effect by avoiding CO2 permeation and stabilizing N2 and O2 selectivity.

Short sisal fiber composites (SSFCs) based on a pectin matrix were prepared and characterized mechanical and optically. Different concentrations (1–30 wt %) of fibers were used to evaluate the packing effect on the reinforcement of a polymer matrix. Theoretical models were used to obtain the maximum packing or volume fraction (ϕ_max) of randomly oriented short fibers and its relationship with the mechanical parameters. A higher elastic modulus and tensile strength were observed when the fiber content was increased in the composite at a fixed aspect ratio (length/diameter = 2.8). Material selection charts showed that SSFCs with a fiber concentration of 20 wt % had a higher reinforcement effect at ϕ_max, as was predicted through theoretical models. Nevertheless, SSFCs with a fiber concentration of 7 wt % presented optimum reinforcement because it resulted in the strongest and lightest composite material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47821.

The aim of this work was to prepare blend membranes of a polyetherimide (PEI) and different ratios of a microporous polyimide (PIM‐B) in order to obtain an improved material for gas selectivity. Miscibility of the membranes was studied through fourier transform infrared spectroscopy (FTIR), Fluorescence, ultraviolet‐visible spectroscopy (UV–vis), polarize light microscope images, X‐ray diffraction (XRD), and differential scanning calorimetry analysis. Gas permeability assays were also performed. Results showed blends were partially miscible along the different ratios due to the existence of: (i) absorption shoulders at lower wavenumbers on the carbonyl stretching band; (ii) red‐shifting of Fluorescence and UV–vis absorption bands; (iii) decreasing of d‐spacing as the amount of PIM‐B phase increased; and (iv) composition‐dependent glass transition temperatures (T_gs). The mobility selectivity (D_i/j) dominated H₂ and O₂ gas separations. High solubility coefficients (S) linked to PIM‐B microporosity improved the ideal gas selectivity of the blend membranes. PEI/PIM‐B membrane at the ratio of 80/20 showed impressive H₂/CO₂ (8.66) and O₂/N₂ (10.90) gas separation factors. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44682.