We have prepared all-biopolymer nanocomposite films using lignin as a filler and cellulose triacetate (CTA) as a polymer matrix, and characterized them by several analytical methods. Three types of lignin were tested: organosolv, hydrolytic and kraft, with or without acetylation. They were used in the form of nanoparticles incorporated at 1 wt% in CTA. Self-supported films were prepared by vapor-induced phase separation at controlled temperature (35-55 °C) and relative humidity (10-70%). The efficiency of acetylation of each type of lignin was studied and discussed, as well as its effects on film structure, homogeneity and mechanical properties. The obtained results are explained in terms of intermolecular filler-matrix interaction at the nanometer scale, for which the highest mechanical resistance was reached using hydrolytic lignin in the nanocomposite.

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Nanotechnology is focused on the development and application of novel nanomaterials with particular physicochemical properties. Palladium nanoparticles (PdNPs) have been used as antimicrobials, antifungals, and photochemicals and for catalytic activity in dye reduction. In the present investigation, we developed and characterized PdNPs as a carrier of quercetin and initiated a study of its effects in colorectal cancer cells. PdNPs were first functionalized with polyvinylpyrrolidone (PVP) and then coupled to quercetin (PdNPs-PVP-Q). Our results showed that quercetin was efficiently incorporated to PdNPs-PVP, as demonstrated using UV/Vis and FT-IR spectroscopy. Using transmission electron microscopy, we demonstrated a reduction in size from 3–14.47 nm of PdNPs alone to 1.8–7.4 nm of PdNPs-PVP and to 2.12–3.14 of PdNPs-PVP-Q, indicating an increase in superficial area in functionalized PdNPs-Q. Moreover, hydrodynamic size studies using dynamic light scattering showed a reduction in size from 2120.33 nm ± 112.53 with PdNPs alone to 129.96 nm ± 6.23 for PdNPs-PVP-Q, suggesting a major reactivity when quercetin is coupled to nanoparticles. X-ray diffraction assays show that the addition of PVP or quercetin to PdNPs does not influence the crystallinity state. Catalytic activity assays of PdNPs-PVP-Q evidenced the chemical reduction of 4-nitrophenol, methyl orange, and methyl blue, thus confirming an electron acceptor capacity of nanoparticles. Finally, biological activity studies using MTT assays showed a significant inhibition (p < 0.05) of cell proliferation of HCT-15 colorectal cancer cells exposed to PdNPs-PVP-Q in comparison to untreated cells. Moreover, treatment with PdNPs-PVP-Q resulted in the apoptosis activation of HCT-15 cells. In conclusion, here we show for the first time the development of PdNPs-PVP-Q and evidence its biological activities through the inhibition of cell proliferation and apoptosis activation in colorectal cancer cells in vitro.

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Activated carbon particles were obtained by a solvatation method and added as fillers in cellulose triacetate as polymeric matrix. Various composite films were prepared by solvent casting at different controlled temperature and relative humidity (35-558 C, 10-70% RH) conditions, for three different filler loadings (0, 1 and 3%). Scanning electron microscopy (SEM) images revealed that for slow solvent evaporation rates (low temperature and high RH) a non-agglomerated composite film is achieved. This condition observed in SEM was correlated to the film with the best mechanical properties found by stress-strain and creep tests. Water flux and mechanical resistance is also higher for the membrane obtained at the best synthesis conditions found (M1) (358C, 70% RH). Contact angle measurements indicated that there is differentiation among membranes of different carbon loading respect to M1, associated to surface homogeneity. Atomic force microscopy (AFM) images showed structural variation among membranes (M1 and its counterpart without carbon) in the nanoscale. Contrast phase AFM analysis exposed homogeneous dispersion of activated carbon particles on membrane M1. Major adhesion between entangled polymer network and activated carbon is postulated as the main factor for the composite polymer proper structural performance. 992 L. Ballinas-Casarrubias et al.Note: Conditions for membranes of CTA and AC tested (carbon loading, relative humidity, temperature and vapor pressure as calculated from a water psychrometric chart at different temperatures). Stress at break (average of three measurements each) and water flux obtained in a continuous cell at 1.4 MPa, total membrane area ¼ 266 cm 2 , operation time ¼ 8 h.