Despite the proven therapeutic role of capsaicin in human health, its usage is still hampered by its high pungency. In this sense, nonpungent capsaicin analogues as olvanil are a feasible alternative ...to the unpleasant sensations produced by capsaicin while maintaining a similar pharmacological profile. Olvanil can be obtained by a lipase‐catalyzed chemoenzymatic process. In the present work, recombinant Candida antarctica lipase B (CALB) was expressed in Pichia pastoris and subsequently immobilized by cross‐linked enzyme aggregate (CLEA) methodology for the synthesis of olvanil. The CALB‐CLEAs were obtained directly from the fermentation broth of P. pastoris without any purification step in order to assess the role of the contaminant proteins of the crude extract as co‐feeders. The CALB‐CLEAs were also bioimprinted to enhance the catalytic performance in olvanil synthesis. When CALB was precipitated with isopropanol, the obtained CALB‐CLEAs exhibited the highest activity in the synthesis of olvanil, regardless of the glutaraldehyde concentration. The maximum product synthesis was found at 72 hr obtaining 6.8 g L−1 of olvanil with a reaction yield of 16%. When CALB was bioimprinted with olvanil, the synthesis was enhanced 1.3 times, reaching 10.7 g L−1 of olvanil at 72 hr of reaction with a reaction yield of 25%. Scanning electron microscopy images indicated different morphologies of the CLEAs depending on the precipitating agent and the template used for bioimprinting. Recombinant CALB‐CLEAs obtained directly from the fermentation broth are a suitable alternative to commercial enzymatic preparations for the synthesis of olvanil in organic medium.
In order to provide a second economic life to agave fibers, an important waste material from the production of tequila, filaments based on polylactic acid (PLA) were filled with agave fibers (0, 3, ...5, 10 wt%), and further utilized to produce biocomposites by fused deposition modeling (FDM)-based 3D printing at two raster angles (−45°/45° and 0°/90°). Differential scanning calorimetry, water uptake, density variation, morphology, and composting of the biocomposites were studied. The mechanical properties of the biocomposites (tensile, flexural, and Charpy impact properties) were determined following ASTM international norms. The addition of agave fibers to the filaments increased the crystallinity value from 23.7 to 44.1%. However, the fibers generated porous structures with a higher content of open cells and lower apparent densities than neat PLA pieces. The printing angle had a low significant effect on flexural and tensile properties, but directly affected the morphology of the printed biocomposites, positively influenced the impact strength, and slightly improved the absorption values for biocomposites printed at −45°/45°. Overall, increasing the concentrations of agave fibers had a detrimental effect on the mechanical properties of the biocomposites. The disintegration of the biocomposites under simulated composting conditions was slowed 1.6-fold with the addition of agave fibers, compared to neat PLA.
A multilevel factorial design of 2
with 12 experiments was developed for the preparation of cellulose nanocrystals (CNC) from
Weber var. Azul bagasse, an agro-industrial waste from tequila ...production. The studied parameters were acid type (H
SO
and HCl), acid concentration (60 and 65 wt% for H
SO
, 2 and 8N for HCl) temperature (40 and 60 °C for H
SO
, 50 and 90 °C for HCl), and hydrolysis time (40, 55 and 70 min for H
SO
; and 30, 115 and 200 min for HCl). The obtained CNC were physical and chemically characterized using dynamic light scattering (DLS), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XDR) techniques. The maximum CNC yield was 90 and 96% for HCL and H
SO
, respectively, and the crystallinity values ranged from 88-91%. The size and morphology of
CNC strongly depends on the acid type and hydrolysis time. The shortest CNC obtained with H
SO
(65 wt%, 40 °C, and 70 min) had a length of 137 ± 68 nm, width 33 ± 7 nm, and height 9.1 nm, whereas the shortest CNC obtained with HCl (2 N, 50 °C and 30 min) had a length of 216 ± 73 nm, width 69 ± 17 nm, and height 8.9 nm. In general, the obtained CNC had an ellipsoidal shape, whereas CNC prepared from H
SO
were shorter and thinner than those obtained with HCl. The total sulfate group content of CNC obtained with H
SO
increased with time, temperature, and acid concentration, exhibiting an exponential behavior of CSG=aebt.
In this study, blends of poly(lactic acid) (PLA)/linear medium density polyethylene (LMDPE) at different weight ratios were prepared by rotational molding. Two mixing strategies were used to evaluate ...the effect of phase dispersion on the physical and mechanical properties: (i) Dry-blending (DB) using a high shear mixer, and (ii) melt-blending (MB) using a twin-screw extruder. Thermal, morphological, and mechanical analyses were performed on the neat polymers and their blends. The thermal analysis was completed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and the blends prepared by MB had lower thermal stability than the ones prepared via DB due to some thermo-oxidative degradation through the double thermal process (extrusion and rotomolding). The morphology of the rotomolded parts showed that DB generated larger particle sizes (around 500 µm) compared to MB (around 5 µm) due to the shear and elongational stresses applied during extrusion. The tensile and flexural properties of the rotomolded parts combined the PLA stiffness with the LMDPE toughness independent of the blending technique. Neat PLA presented increments in tensile strength (54%) and flexural strength (111%) for DB compared with MB. A synergistic effect in impact strength was observed in blends with 12 and 25 wt. % of PLA prepared by DB.
Corneal chemical burns (CCBs) frequently result in corneal fibrosis or haze, an opacity of the cornea that obstructs vision and induces corneal blindness. Diverse strategies have been employed to ...prevent or reduce CCB-related corneal haze. In this study, we evaluated the physicochemical characteristics and biologic effects of a topical pirfenidone (PFD)-loaded liposomal formulation (PL) on a corneal alkali burn mice model. We found that PL was appropriate for ocular application due to its physiologic tear pH, osmolarity and viscosity suitable for topical ophthalmic use. Regarding its therapeutic activity, PL-treated mice had significantly reduced haze size and density, corneal edema, corneal thickness, and corneal inflammatory infiltration, in contrast to PFD in aqueous solution (
< 0.01). Importantly, the antifibrotic activity of PL (reduction of corneal haze) was associated with modulation of transforming growth factor (TGF)-β and Interleukin (IL)-1β genes. PL suppressed TGF-β expression and restored normal IL-1β expression in corneal tissue more efficiently in contrast to PFD in aqueous solution. In conclusion, PFD showed essential anti-inflammatory and anti-fibrotic effects in the treatment of alkali burns. Noteworthy, a new formulation of PFD-loaded liposomes remarkably improved these effects, standing out as a promising treatment for corneal haze.
A detailed study of the different structural transitions of the triblock copolymer PEO
-PPO
-PEO
(P104) in water, in the dilute and semi-dilute regions, is addressed here as a function of temperature ...and P104 concentration (C
) by mean of complimentary methods: viscosimetry, densimetry, dynamic light scattering, turbidimetry, polarized microscopy, and rheometry. The hydration profile was calculated through density and sound velocity measurements. It was possible to identify the regions where monomers exist, spherical micelle formation, elongated cylindrical micelles formation, clouding points, and liquid crystalline behavior. We report a partial phase diagram including information for P104 concentrations from 1 × 10
to 90 wt.% and temperatures from 20 to 75 °C that will be helpful for further interaction studies with hydrophobic molecules or active principles for drug delivery.
The interactions of proteins and other molecules and their adsorption onto substrates is a fascinating topic that has been applied to surface technologies, biosensors, corrosion studies, ...biotechnologies, and other fields. The success of these applications requires a previous characterization using some analytical techniques that, ordinarily, are not electrochemical. This work proposes analyzing the variation of the double-layer capacitance obtained through impedance electrochemical spectroscopy as an alternative strategy to show evidence of the interactions between proteins and triblock copolymers. The proposal is supported through the study of the interaction and adsorption of bovine serum albumin (BSA) and a commercial triblock copolymer (P103) in phosphate buffer on a gold electrode. The double-layer capacitance and the apparent interface thickness vs polarization potential curves as well as the potential of zero charge for pure P103 (0.6 wt %, corresponding to 6 g L–1), pure BSA (3 mg mL–1), and P103-BSA solutions (0.6 wt % and 3 mg mL–1, respectively) are sensitive enough to show not only the interaction and the adsorption of the species but also the polarization potential where these interactions are taking place. A qualitative and quantitative analysis concerning the double-layer capacitance behavior is given. The significance and impact of this work is also presented.
Hybrid hydrogels composed of chitosan (CS) and hyaluronic acid (HA) and collagen (Coll) were prepared by polyelectrolyte complex self-assembly. These scaffolds displayed a good intermingling of the ...polymeric chains, with porosities above 80% and good interconnected structures with pore sizes lying between 30–115 μm. The ionic interactions between CS and HA make the scaffolds have larger storage modulus and longer LVR regions than their pure counterparts. Both quantities progressively decrease as the HA and Coll concentrations in the formulation rise. These hybrid hydrogels showed good swelling extents from ca. 420 to ca. 690% and suitable resistance to enzymatic degradation, which was slightly lower for scaffolds containing CS to larger extents or Coll in the formulation. All scaffolds were largely cytocompatible and allowed the proliferation of both mouse fibroblast and human keratinocytes with their infiltration inside, thus becoming optimal matrices for intended tissue engineering applications as well as transdermal drug delivery depots.
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•Hybrid scaffolds were obtained by polyelectrolyte ionic self-assembly•Scaffolds were largely porous with suitable pore sizes for cell proliferation•Scaffolds showed exceptional swelling and good resistance to enzymatic attack•They were nontoxic and enabled cell proliferation and infiltration inside the scaffold
Health sciences; Medicine; Materials science; Biomaterials
Capsaicin analogues are typically synthetized by condensation of the amide group of vanillylamine with a fatty acid derivative. The enzyme of choice to perform this reaction is
Candida antarctica
...lipase B; however, this enzyme is unable to react with the phenolic substiruents of the vanillyl ring. So far, this can only be achieved chemically, resulting in capsaicin esters with higher lipophilicity and less irritation than the parent compound. In need of searching for new capsaicin derivatives, we investigated the transesterification of the phenolic OH group of capsaicin and several capsaicin analogues by
Candida antarctica
lipase A (CALA) with vinyl esters. Capsaicin esters were successfully synthetized with a reaction yield of 80.6% and 57.5% with vinyl butyrate and vinyl laurate, respectively. When the reactions were performed with capsaicin analogues of different acyl chain lengths, CALA exhibited a noticeable transesterification preference for medium-length capsaicin analogues. In an attempt to explore the catalytic limits of CALA, we performed the transesterification of capsaicin from
Capsicum
oleoresin. The results showed similar transesterification yields to those obtained with semi-pure capsaicin. Within our knowledge, this is the first report to achieve the synthesis of phenolic OH esters of capsaicin and capsaicin analogues by enzymatic means.
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