Goycoolea Valencia,  Francisco Martín

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Goycoolea Valencia, Francisco Martín

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Goycoolea Valencia, Francisco Martín

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Biología Celular e Histología

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Open Access
Structural characterization of mesquite (Prosopis velutina) gum and its fractions
(Wiley, 2008-07-31) López Franco, Yolanda L.; Calderón de la Barca, Ana María; Valdez, Miguel Ángel; Peter, Martin G.; Rinaudo, Marguerite; Chambat, Gérard; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología; Facultades de la UMU::Facultad de Biología
Structural and physicochemical characteristics of mesquite gum (from Prosopis velutina) were investigated using FT-IR spectroscopic, mass spectrometric and chromatographic methods. Four fractions (F-I, F-IIa, F-IIb and F-III) were isolated by hydrophobic interaction chromatography. The samples were characterized and analyzed for their monosaccharide and oligomers composition by high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). L-Arabinose (L-Ara) and D-galactose (D-Gal) were found as the main carbohydrate constituent residues in the polysaccharides from mesquite gum and their ratio (L-Ara/D-Gal) varied within the range 2.54 to 3.06 among the various fractions. Small amounts of D-glucose (D-Glc), D-mannose (D-Man) and D-xylose (D-Xyl) were also detected, particularly in Fractions IIa, IIb and III. Infrared spectroscopy identified polysaccharides and protein in all the samples. Data from mass spectrometry (MALDI-TOF MS) was consistent with the idea that the structure corresponding to the periphereal chains of Fraction I is predominantly a chain of pentoses attached to uronic acid.
Open Access
An infrared investigation in relation with chitin and chitosan characterization
(Elsevier, 2001-01-12) Brugnerotto, J.; Lizardi, J.; Argüelles Monal, Waldo; Desbrières, J.; Rinaudo, Marguerite; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología
The use of infrared spectroscopy for characterization of the composition of chitin and chitosan covering the entire range of degree of acetylation (DA) and a wide variety of raw materials is examined further. The ratio of absorbance bands selected was calibrated using 1H liquid and 13C CP-MAS solid-state NMR as absolute techniques. IR spectra of the structural units of these polymers validated the choice of baselines and characteristic bands. The bands at 1650 and 1320 cm-1 were chosen to measure the DA. As internal reference, the intensities at 3450 and 1420 cm-1 were evaluated. The absorption band ratios involving the reference at 3450 cm-1 had poorer fit. The absorption ratio A1320/A1420 shows superior agreement between the absolute and estimated DA-values (DA% = 31.92A1320/A1420 - 12.20; r = 0.990)
Open Access
Viscosity of galactomannans at alkaline and neutral pH: evidence of ‘hyperentanglement’ in solution.
(Elsevier, 1995) Gidley, M.J.; Morris, E. R.; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología
Open Access
Determination of Chitin and protein contents during the isolation of Chitin from shrimp waste
(Wiley, 2006-05-09) Díaz Rojas, Erika I.; Argüelles Monal, Waldo M.; Higuera Ciapara, Inocencio; Hernández, Javier; Lizardi Mendoza, Jaime; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología
Accurate determination of chitin and protein contents in crustacean biomass and the intermediate products during the industrial isolation of chitin cannot be made directly from the total nitrogen content, unless the appropriate corrections are applied. This method, however, is affected by the presence of other nitrogen-containing chemical species that are formed endogenously or by the action of microorganisms during the handling of the sample. Therefore, an alternative rapid method to estimate the contents of these components can be very useful both in research and in various fields of application. An original method has been developed to address this problem. The method consists of the development of a set of equations based on the stoichiometric contents of nitrogen of chitin and protein whereby the amounts of each component can be estimated from the value of the total nitrogen content, provided the rest of the proximate composition of the sample is accurately known. In order to validate the procedure, a set of model mixtures of pure chitin and protein concentrate in the solid state, both extracted from shrimp head waste, are used. Excellent agreement between the predicted and real values of chitin and protein are obtained (R2=0.98, slope=0.90). When the proposed method is tested in the analysis of real samples obtained from five different processing protocols of pretreatment of raw shrimp head, it is found that in general, the values of protein and chitin contents throughout the various stages of the process vary as expected.
Open Access
Chitosan-Alginate Blended Nanoparticles as Carriers for the Transmucosal Delivery of Macromolecules
(American Chemical Society, 2009-06-22) Goycoolea Valencia, Francisco Martín; Giovanna Lollo; Carmen Remuñán-López; Fabiana Quaglia; María J. Alonso; Biología Celular e Histología; Facultades de la UMU::Facultad de Biología
Nanoparticles intended for use in the transmucosal delivery of macromolecules were prepared by the ionic gelation of chitosan (CS) hydrochloride with pentasodium tripolyphosphate (TPP) and concomitant complexation with sodium alginate (ALG). The incorporation of a small proportion of ALG of increasing molecular weight (Mw; from 4 to 74 kDa) into the nanoparticles led to a monotonic increase in colloidal size from ∼260 to ∼525 nm. This increase in size was regarded as a consequence of the formation of radually more expanded structures. Insulin, taken as a model peptide, was associated to CS-TPP-ALG nanoparticles with efficiencies in the range of ∼41 to ∼52%, irrespective of the Mw of the ALG incorporated in the formulation. These CS-TPP-ALG nanoparticles exhibited a capacity to enhance the systemic absorption of insulin after nasal administration to conscious rabbits. Interestingly, it was observed that the duration of the hypoglycaemic response was affected by the ALG’s Mw. Briefly, this work describes a new nanoparticulate composition of potential value for increasing nasal insulin absorption.
Open Access
Chitosan-based nanocapsules: physical characterization, stability in biological media and capsaicin encapsulation
(Springer-Verlag, 2012-05-08) Goycoolea Valencia, Francisco Martín; Angela Valle-Gallego; Rossana Stefani; Bianca Menchicchi; Laurent David; Cyrille Rochas; Manuel J. Santander-Ortega; María J. Alonso; Biología Celular e Histología; Facultades de la UMU::Facultad de Biología
This study addresses the effect of the degree of Nacetylation (DA ~1.4–56 %) of chitosan (CS) of low and medium molecular weight (Mw ~9.5–13.2 and ~122–266 kDa, respectively) on the biophysical properties, colloidal stability and encapsulation efficiency of capsaicin (a lipophilic drug currently used in pain therapy) of CS-based nanocapsules (NCs). The average diameter of the NCs varied within the range of ~150–200 nm, but it was slightly higher for NCs comprising high Mw CS than for those with low Mw CS. The zeta potential (ζ) was highly positive and clearly dependent on the Mw of CS, exhibiting a monotonic decreasing trend concomitant with the increase in DA. Both results suggest that Mw and DA of CS have an effect on the disposition of the polysaccharide onto the phospholipidic surface. Synchrotron SAXS studies revealed a monotonic increase in Bragg interplanar distances (from ~55 up to ~67 Å) as a function of the DA, a finding that agrees with previous results that are consistent with the capacity of hydrophobic domains to disturb the crystalline state ofgelled phospholipidic membranes. Colloidal stability studies carried out in cell-culture biological media revealed the determinant role of hydration forces, a short-range repulsive interaction, on the stability of the NCs. Finally, Mw and DA of CS both influenced the encapsulation efficiency of capsaicin, thus showing the effect of the harnessed NCs shell on its capacity to encapsulate lipophilic drugs.
Open Access
Development and characterization of nanocapsules comprising dodecyltrimethylammonium chloride and K-carrageenan.
(Elsevier, 2011-03-23) Rosas Durazo, A.; Lizardi, J.; Higuera Ciapara, I.; Argüelles Monal, W.; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología; Facultades de la UMU::Facultad de Biología
The aim of this work was to develop and characterize a new type of nanocapsules. To this end, a nanoemulsion bearing an oily core (Miglyol 812) was obtained by spontaneous emulsification and stabilized by dodecyl-trimethylammonium chloride (DTAC), a commercial cationic surfactant; this nanoemulsion was coated with proportionally very small amounts of κ-carrageenan (at molar charge ratios of Z ≤ 0.0045) that interact predominantly by an electrostatic mechanism with the positively charged sites at the polar heads of DTAC at the nanoemulsion's surface to harness nanocapsules of average size ∼250–330 nm and zeta potential (ζ) ranging from ∼+80 to +7 mV. The potential application of the new type of developed nanosystems as drug delivery vehicles has yet to be investigated and fully realized.
Open Access
Molecularly Imprinted Chitosan-Genipin Hydrogels with Recognition Capacity toward o-Xylene
(American Chemical Society, 2007-10-18) Bibiana M. Espinosa-García; Waldo M. Argüelles-Monal; Javier Hernández; Leticia Félix-Valenzuela; Niuris Acosta; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología; Facultades de la UMU::Facultad de Biología
A molecularly imprinted material was developed from hydrogels of chitosan (CS) cross-linked with genipin (GNP) using o-xylene as the template molecule. Gelling time, mechanical, and diffusion properties of CS-GNP hydrogels were initially investigated to establish optimal conditions to prepare molecularly imprinted hydrogels (MIHs). The elastic modulus was found to be directly proportional to the degree of cross-linking (R ) moles of genipin/ moles of glucosamine) while the diffusion of water, as monitored by magnetic resonance imaging, decreased with R. CS-GNP hydrogels of varying R were imprinted with o-xylene (MIHo-xylene). The adsorption capacity of o-xylene by MIHo-xylene was greater than the corresponding control hydrogels, particularly at R ) 0.25. Freundlich isotherms yielded a better fitness than Langmuir ones and afforded n and Qmaxvalues of 2.55 and 103.3 mg/g, respectively. The imprinted hydrogel showed the highest adsorption capacity for o-xylene; however, the material was not highly selective as it also exhibited the capacity to adsorb m- and p-xylene isomers. In turn, the MIHoxylene showed a low adsorption when 2-fluorotoluene was used in rebinding experiments, suggesting that molecular recognition by the binding sites is influenced by the electronic and steric properties of the analyte molecule, thus effectively confirming the imprinting effect within the MIHo-xylene network. This work opens the possibility to future development of materials with the capacity to adsorb o-xylene analogue molecules such as contaminants bearing chlorinated aromatic structures.
Open Access
Microencapsulation of astaxanthin in a chitosan matrix
(Elsevier, 2004-02-06) Higuera Ciapara, I.; Felix Valenzuela, L.; Argüelles Monal, W.; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología
Synthetic astaxanthin was microencapsulated in a chitosan matrix cross-linked with glutaraldehyde by using the method of multiple emulsion/solvent evaporation. A powdered product containing microcapsules with a diameter of 5–50 mm was obtained. The stability of the pigment in the microcapsules was studied under storage at 25, 35 and 45 8 °C for 8 weeks by measuring isomerization and loss of concentration of pigment. Pigments were extracted from the microcapsules with a mixture of dichloromethane/methanol (50:50) and the astaxanthin was analyzed by HPLC with a diode array detector (480 nm). Results showed that the microencapsulated pigment did not suffer isomerization nor chemical degradation under the investigated storage conditions
Open Access
Kinetics of gelation and thermal sensitivity of N-Isobutyryl Chitosan hydrogels
(American Chemical Society, 2005-06-25) Félix, Leticia; Hernández, Javier; Argüelles Monal, Waldo M.; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología
N-Acylation of chitosan with carboxylic anhydrides in dilute acetic acid/methanol has been a well documented strategy to selectively modify chitosan. Although this reaction is known to lead to irreversible gel formation, the kinetics and mechanism of this process have not so far been addressed. To this purpose, gel formation during the N-isobutyrylation of chitosan was investigated as a function of the reaction stoichiometry (R), chitosan concentration, and temperature by small deformation oscillatory rheology. Gel formation follows closely the chemical reaction and it proceeds predominantly under second-order kinetics as established from the dependence of critical gel time, tgel, on R and concentration. The activation energy value derived from tgel vs 1/T data (Ea ) 68.29 ( 1.80 kJ/mol) was almost identical to values reported for the chitosan N-acetylation reaction in previous studies. An excess isobutyric anhydride is suggested to be necessary for nucleation and hydrophobic association. The potential application of N-isobutyrylchitosan (NIBC) hydrogels in the design of thermally sensitive materials is also demonstrated.