Browsing by Author "Gonzalez-Henriquez, Carmen M."

Now showing 1 - 8 of 8
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    Biocompatible and bioactive PEG-Based resin development for additive manufacturing of hierarchical porous bone scaffolds
    (2023) Sarabia-Vallejos, Mauricio A.; Cerda-Iglesias, Felipe E.; Terraza, C. A.; Cohn-Inostroza, Nicolas A.; Utrera, Andres; Estrada, Manuel; Rodriguez-Hernandez, Juan; Gonzalez-Henriquez, Carmen M.
    Bone diseases can often result in patient bone fragility. Different bone problems include low bone density, osteoporosis, and other bone diseases. Such bone diseases, ailments, and malfunctions often require complex and expensive treatments. In this study, we synthesized a new type of DLP resin for 3D printing purposes based on poly(ethylene glycol diacrylate) (PEGDA) and acrylic acid (AAc). In addition, using a porogen within the photopolymerizable resin allowed us to fabricate hierarchical interconnected porous structures. These structures combine the pores resulting from the CAD design with those obtained by the lixiviation of the porogen. Finally, bioactive particles were added to the mixture to increase the material's biocompatibility, thus proving the strategy's potential to include active compounds for particular purposes. Our results demonstrate that including the photoabsorber, Orange G, considerably increases the printing precision and resolution of the synthesized resin, making it possible to obtain printed parts with intricate and complex geometries with high accuracy and definition. Nano-hydroxyapatite (nHA) inclusion significantly increases the material's biocompatibility and mechanical stiffness (similar to 47 % increase, from 5.47 MPa to 8.02 MPa).
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    Fabrication and Testing of Multi-Hierarchical Porous Scaffolds Designed for Bone Regeneration via Additive Manufacturing Processes
    (2022) Gonzalez-Henriquez, Carmen M.; Rodriguez-Umanzor, Fernando E.; Acuna-Ruiz, Nicolas F.; Vera-Rojas, Gloria E.; Terraza-Inostroza, Claudio; Cohn-Inostroza, Nicolas A.; Utrera, Andres; Sarabia-Vallejos, Mauricio A.; Rodriguez-Hernandez, Juan
    Bone implants or replacements are very scarce due to the low donor availability and the high rate of body rejection. For this reason, tissue engineering strategies have been developed as alternative solutions to this problem. This research sought to create a cellular scaffold with an intricate and complex network of interconnected pores and microchannels using salt leaching and additive manufacturing (3D printing) methods that mimic the hierarchical internal structure of the bone. A biocompatible hydrogel film (based on poly-ethylene glycol) was used to cover the surface of different polymeric scaffolds. This thin film was then exposed to various stimuli to spontaneously form wrinkled micropatterns, with the aim of increasing the contact area and the material's biocompatibility. The main innovation of this study was to include these wrinkled micropatterns on the surface of the scaffold by taking advantage of thin polymer film surface instabilities. On the other hand, salt and nano-hydroxyapatite (nHA) particles were included in the polymeric matrix to create a modified filament for 3D printing. The printed part was leached to eliminate porogen particles, leaving homogenously distributed pores on the structure. The pores have a mean size of 26.4 +/- 9.9 mu m, resulting in a global scaffold porosity of similar to 42% (including pores and microchannels). The presence of nHA particles, which display a homogeneous distribution according to the FE-SEM and EDX results, have a slight influence on the mechanical resistance of the material, but incredibly, despite being a bioactive compound for bone cells, did not show a significant increase in cell viability on the scaffold surface. However, the synergistic effect between the presence of the hydrogel and the pores on the material does produce an increase in cell viability compared to the control sample and the bare PCL material.
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    Synthesis of dimethyl- and diphenylsilane-based oligo(azine)s: Thermal, optical, electronic, and morphological properties
    (2022) Sobarzo, Patricio A.; Jessop, Ignacio A.; Perez, Yasmin; Hauyon, Rene A.; Velazquez-Tundidor, Maria V.; Medina, Jean; Gonzalez, Alexis; Garcia, Luis E.; Gonzalez-Henriquez, Carmen M.; Coll, Deysma; Ortiz, Pablo A.; Tundidor-Camba, Alain; Terraza, Claudio A.
    Four new oligo(azine)s were synthesized from dimethyldiphenylsilane and tetraphenylsilane core-based dialdehydes and hydrazine by high-temperature polycondesation and proposed as materials for optoelectronic applications. The oligo(azine)s were characterized by EA, FT-IR, and NMR. Although most of samples were poorly soluble, TPS-containing PAZ-4 was soluble in aprotic polar solvents. According to SEC and FT-IR studies, the samples were oligomers with up to five repeating units long. TGA showed highly stable samples with TDT10% over 420 degrees C except for PAZ-1 that contains a DMS core along with phenyl units, and thus, the lowest carbon content in the series. From DSC analysis, the substitution of phenyl groups in PAZ-1/3 by biphenyl moieties in PAZ-2/4 allowed to obtain oligo(azine)s with lower T-g values. PAZ-4 showed a UV-A absorption with optical band-gap values of 2.91 and 2.65 eV from UV-vis (solution) and DRS (films), respectively. PL analysis showed a violet emission. PAZ-4 showed resistivity of 29.24 omega cm, similar to wide-band gap materials. Their contact angle measurements showed a critical surface tension of 42.29 dynes/cm, revealing its hydrophobicity. AFM analysis indicated that the PAZ-4 films had homogeneous surfaces. Young's modulus close to 4.46 GPa was established by microindentation for the PAZ-4 thin-films.
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    Theoretical and Experimental Vibrational Spectroscopic Investigation of Two R1R2-Diphenylsilyl-Containing Monomers and Their Optically Active Derivative Polymer
    (2014) Gonzalez-Henriquez, Carmen M.; Terraza, Claudio A.; Sarabia, Mauricio
    FT-IR and Raman spectra of bis(4-aminophenyl)diphenylsilane (DIA) and a dicarboxylic acid containing the imide function and a L-alanine moiety (L-ALA) and their resultant polymer (PALA) were recorded in the 500-4000 cm(-1) and 400-3800 cm(-1) regions, respectively. The optically active poly(imide-amide) obtained has two sp(3) carbons in the main chain, favoring its flexibility. Raman analysis identifies the fluorescence produced by the electronic conjugation between the aromatic rings and the amidic groups, which affects the molecular fine structure. Thus, the theoretical study of the vibrational patterns has become a support and a complementary technique for the characterization of this fluorescent system. The optimized molecular geometry of the monomers and the polymeric unit using B3LYP and HF methods at the 6-31G(d) level of theory were used for the vibrational assignments. Thus, the small variations between the calculated and experimental vibration values could be related to possible intra- and/or intermolecular interactions or to the existence of a charge transfer phenomena between a donor or acceptor group within the system.
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    Thermoresponsive microwrinkled hydrogel surfaces with modulated chemical composition
    (2021) Gonzalez-Henriquez, Carmen M.; Medel-Molina, Gonzalo E.; Rodriguez-Umanzor, Fernando E.; Inostroza, Claudio Terraza; Sarabia-Vallejos, Mauricio A.; Rodriguez-Hernandez, Juan
    Smart wrinkled hydrogel patterns with modulated chemical composition and wrinkle characteristics (amplitude and period) were formed by taking advantage of surface instabilities using a simple, cost-affordable, and robust method. The microstructured surfaces were prepared by dip coating and were designed to be stimuli-responsive by introducing poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) in the initial feed. For this purpose, a silylated substrate surface serves as an anchor for the non-polymerized hydrogel molecules, thus forming a homogenous and reproducible coating. Once the film was achieved, the samples were exposed to vacuum and UV irradiation to form wrinkled patterns spontaneously. The response of the thermosensitive wrinkles reveals significant variations in the properties of the wrinkled films depending on the temperature. In addition to the simplicity, this deposition strategy allows the preparation of highly reproducible films using an easy-scalable methodology with potential interest for industrial applications.
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    Thiophene- and bithiophene-based π-conjugated Schiff base oligomers containing binaphthalene moieties in the backbone. Properties and computational simulations
    (Royal Sociaty of Chemistry, 2024) González Guzmán, Alexis Fabián; Mariman Marchant, Andrea Paz; Hauyón Sepúlveda, René Alejandro; Pavéz Lizana, Danitza Belén; Saldías Barros, César Antonio; Schott Verdugo, Eduardo; Zarate, Ximena; García Paredes, Luis Enrique; Gonzalez-Henriquez, Carmen M.; Jessop, Ignacio A.; Tundidor Camba, Alain; Sobarzo Aucal, Patricio Antonio; Terraza Inostroza, Claudio
    New pi-conjugated Schiff base oligomers (o-AZdAN1Th and o-AZdAN2Th) based on a binaphthalene core and containing thiophene or bithiophene units in their backbone were synthesized from the reaction between [1,1 '-binaphthalene]-4,4 '-diamine with thiophene-2,5-dicarbaldehyde and [2,2 '-bithiophene]-5,5 '-dicarbaldehyde by a high-temperature polycondensation method. These new materials were slightly soluble in non-protic polar solvents, such as chloroform and dichloromethane. From GPC analysis of the CHCl3-soluble fraction, o-AZdAN1Th was found to be a tetramer, whereas o-AZdAN2Th was a trimer with 1.4 kDa and 1.3 kDa average molecular weight (Mn), respectively. Both samples exhibited high thermal stability with T5% values of 452 degrees C and 456 degrees C and relatively high Tg values of 346 degrees C and 384 degrees C, for o-AZdAN1Th and o-AZdAN2Th, respectively. The samples showed absorptions in the deep-blue (o-AZdAN1Th) and blue (o-AZdAN2Th) regions of the visible spectrum, and emission responses at 387 nm and 447 nm, respectively, with moderate Stokes shifts (77-95 nm). Their optical and electronic properties were similar to those described for thiophene-based materials, with optical bandgap values close to 2.4 eV. HOMO energy values of -5.98 and -5.95 eV and LUMO energy values of -3.87 eV and -3.84 eV were obtained for o-AZdAN1Th and o-AZdAN2Th, respectively. Theoretical DFT and TD-DFT calculations were used to compare the effect of increasing thiophene units along the backbone for the real and also theoretical o-AZdANxTh samples (x = 3 and 4 thiophene units). According to our study, these two new thiophene-based can be proposed for optoelectronic applications., Schiff base oligomers based on a binaphthalene core were synthesized from [1,1 '-binaphthalene]-4,4 '-diamine with thiophene-2,5-dicarbaldehyde and [2,2 '-bithiophene]-5,5 '-dicarbaldehyde by a high-temperature polycondensation method.
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    Thiophene- and bithiophene-based π-conjugated Schiff base oligomers containing binaphthalene moieties in the backbone. Properties and computational simulations
    (2024) Gonzalez, Alexis F.; Mariman, Andrea P.; Hauyon, Rene A.; Pavez-Lizana, Danitza; Saldias, Cesar; Schott, Eduardo; Zarate, Ximena; Garcia, Luis; Gonzalez-Henriquez, Carmen M.; Jessop, Ignacio A.; Tundidor-Camba, Alain; Sobarzo, Patricio A.; Terraza, Claudio A.
    New pi-conjugated Schiff base oligomers (o-AZdAN1Th and o-AZdAN2Th) based on a binaphthalene core and containing thiophene or bithiophene units in their backbone were synthesized from the reaction between [1,1 '-binaphthalene]-4,4 '-diamine with thiophene-2,5-dicarbaldehyde and [2,2 '-bithiophene]-5,5 '-dicarbaldehyde by a high-temperature polycondensation method. These new materials were slightly soluble in non-protic polar solvents, such as chloroform and dichloromethane. From GPC analysis of the CHCl3-soluble fraction, o-AZdAN1Th was found to be a tetramer, whereas o-AZdAN2Th was a trimer with 1.4 kDa and 1.3 kDa average molecular weight (Mn), respectively. Both samples exhibited high thermal stability with T5% values of 452 degrees C and 456 degrees C and relatively high Tg values of 346 degrees C and 384 degrees C, for o-AZdAN1Th and o-AZdAN2Th, respectively. The samples showed absorptions in the deep-blue (o-AZdAN1Th) and blue (o-AZdAN2Th) regions of the visible spectrum, and emission responses at 387 nm and 447 nm, respectively, with moderate Stokes shifts (77-95 nm). Their optical and electronic properties were similar to those described for thiophene-based materials, with optical bandgap values close to 2.4 eV. HOMO energy values of -5.98 and -5.95 eV and LUMO energy values of -3.87 eV and -3.84 eV were obtained for o-AZdAN1Th and o-AZdAN2Th, respectively. Theoretical DFT and TD-DFT calculations were used to compare the effect of increasing thiophene units along the backbone for the real and also theoretical o-AZdANxTh samples (x = 3 and 4 thiophene units). According to our study, these two new thiophene-based can be proposed for optoelectronic applications.
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    Wrinkling on Stimuli-Responsive Functional Polymer Surfaces as a Promising Strategy for the Preparation of Effective Antibacterial/Antibiofouling Surfaces
    (2021) Gonzalez-Henriquez, Carmen M.; Rodriguez-Umanzor, Fernando E.; Alegria-Gomez, Matias N.; Terraza-Inostroza, Claudio A.; Martinez-Campos, Enrique; Cue-Lopez, Raquel; Sarabia-Vallejos, Mauricio A.; Garcia-Herrera, Claudio; Rodriguez-Hernandez, Juan
    Biocompatible smart interfaces play a crucial role in biomedical or tissue engineering applications, where their ability to actively change their conformation or physico-chemical properties permits finely tuning their surface attributes. Polyelectrolytes, such as acrylic acid, are a particular type of smart polymers that present pH responsiveness. This work aims to fabricate stable hydrogel films with reversible pH responsiveness that could spontaneously form wrinkled surface patterns. For this purpose, the photosensitive reaction mixtures were deposited via spin-coating over functionalized glasses. Following vacuum, UV, or either plasma treatments, it is possible to spontaneously form wrinkles, which could increase cell adherence. The pH responsiveness of the material was evaluated, observing an abrupt variation in the film thickness as a function of the environmental pH. Moreover, the presence of the carboxylic acid functional groups at the interface was evidenced by analyzing the adsorption/desorption capacity using methylene blue as a cationic dye model. The results demonstrated that increasing the acrylic acid in the microwrinkled hydrogel effectively improved the adsorption and release capacity and the ability of the carboxylic groups to establish ionic interactions with methylene blue. Finally, the role of the acrylic acid groups and the surface topography (smooth or wrinkled) on the final antibacterial properties were investigated, demonstrating their efficacy against both gram-positive and gram-negative bacteria model strains (E. coli and S. Aureus). According to our findings, microwrinkled hydrogels presented excellent antibacterial properties improving the results obtained for planar (smooth) hydrogels.