Maria Canillas - Academia.edu (original) (raw)

Papers by Maria Canillas

Research paper thumbnail of Self-Photopolymerizable Hydrogel–Ceramic Composites with Scavenger Properties

Polymers, 2022

The photocatalytic behaviours of semiconductive ceramic nanoparticles such as TiO2, ZnO, Fe2O3, a... more The photocatalytic behaviours of semiconductive ceramic nanoparticles such as TiO2, ZnO, Fe2O3, and Fe3O4, have been extensively studied in photocatalysis and photopolymerization, due to their ability to produce radical species under ultraviolet–visible light, and even in dark conditions. In addition, in the form of microparticles, TiO2 and its Magnéli phases are capable of neutralizing radical species, and a heterogeneous catalytic process has been suggested to explain this property, as it is well known as scavenging activity. Thus, in this study, we demonstrate that these ceramic powders, in the form of microparticles, could be used as photoinitiators in UV polymerization in order to synthesize a hydrogel matrix. Them, embedded ceramic powders could be able to neutralize radical species of physiological media once implanted. The hydrogel matrix would regulate the exchange of free radicals in any media, while the ceramic particles would neutralize the reactive species. Therefore, i...

Research paper thumbnail of Synchrotron X-ray microdiffraction to study dental structures in Cretaceous crocodylomorphs

Cretaceous Research, 2021

Synchrotron radiation X-ray microdiffraction (SR-mXRD) has been applied for the first time as a f... more Synchrotron radiation X-ray microdiffraction (SR-mXRD) has been applied for the first time as a fundamental method of analysis to unveil crocodilian teeth growth and development. Teeth from a fossil crocodylomorph from the Upper Cretaceous site of Lo Hueco (Spain) and a modern crocodylian from the living species Crocodylus niloticus have been analysed. Both samples have been studied through Polarized Light Microscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy, Confocal Raman Spectroscopy, and SR-mXRD. Significant differences have been found in hydroxyapatite (HA) crystallite sizes and texture, and the evolution of these two features along teeth depth. The main differences observed in crystallite size are related to postdepositional processes and/or the environmental and functional pressures of teeth during crocodylomorph life, very different from that of the modern specimen. Regarding the crystalline texture in the tooth enamel, it can be linked to teeth functionality during crocodilian life, causing the directed growth of HA crystallites due to the mechanical stress to which they are subjected.

Research paper thumbnail of Novel Osteoinductive and Osteogenic Scaffolds of Monetite, Amorphous Calcium Phosphate, Hydroxyapatite, and Silica Gel: Influence of the Hydroxyapatite/Monetite Ratio on Their In Vivo Behavior and on Their Physical and Chemical Properties

ACS Biomaterials Science & Engineering, 2020

Research paper thumbnail of Composite cryogels for dual drug delivery and enhanced mechanical properties

Polymer Composites, 2017

In this study, we present a simple and effective process that integrates hydrogels with drugs + c... more In this study, we present a simple and effective process that integrates hydrogels with drugs + ceramics via physical crosslinks resulting in improved mechanical properties. These cryogels have the potential for controlled drug release and stimulus responsive behaviour. The hydrogels were produced from polyvinyl alcohol and polyacrylic acid by varying the molecular weight of the polymers, via freeze thawing technique. The cryogels were combined with two ceramics: (1) a combination of beta-tricalcium phosphate, wollastonite, magnesium silicate and (2)titanium dioxide nanopowder. Theophylline, a model drug, was incorporated into the structure to analyse the drug release behaviour. A layered structure was produced by adding both hydrogels + ceramics into a mould where a polyvinyl alcohol dried film acted as a barrier and reinforcing structure. The results showed that the barrier integrated between both hydrogels by a physically crosslinking mechanism. This adhesion was demonstrated using Fourier transform infrared spectroscopy and scanning electron microscopy. Swelling of this composite showed the profile of drug release from both hydrogels + ceramics while simultaneously releasing the drug independently without diffusing via the opposite layer. Finally, mechanical properties were improved with the addition of the ceramics, which demonstrates the potential approach in terms of modification of weak hydrogel systems.

Research paper thumbnail of Processing of hydroxyapatite obtained by combustion synthesis

Boletín de la Sociedad Española de Cerámica y Vidrio, 2017

One of the reasons of implants failure is the stress forces appearing in the material-tissue inte... more One of the reasons of implants failure is the stress forces appearing in the material-tissue interface due to the differences between their mechanical properties. For this reason, similar mechanical properties to the surrounding tissue are desirable. The synthesis of hydroxyapatite by solution combustion method and its processing have been studied in order to obtain fully dense ceramic bodies with improved mechanical strength. Combustion synthesis provides nanostructured powders characterized by a high surface area to facilitate the following sintering. Moreover, synthesis was conducted in aqueous and oxidizing media. Oxidizing media improve homogenization and increase the energy released during combustion. It gives rise to particles whose morphology and sizes suggest lower surface energies compared with aqueous media. Obtained powders were sintered by using a controlled sintering rate schedule. Lower surfaces energies minimize the shrinkage during sintering and relative densities measurements and diametral compression test confirm improved densification and consequently mechanical properties.

Research paper thumbnail of External and internal ontogenetic changes in the first rib

American Journal of Physical Anthropology, 2017

Research paper thumbnail of Calcium phosphates for biomedical applications

Boletín de la Sociedad Española de Cerámica y Vidrio, 2017

b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 6 (2 0 ... more b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 6 (2 0 1 7) 91-112

Research paper thumbnail of An in vivo study on bone formation behavior of microporous granular calcium phosphate

Biomaterials science, Jan 9, 2017

This study was developed based on in vivo investigation of microporous granular biomaterials base... more This study was developed based on in vivo investigation of microporous granular biomaterials based on calcium phosphates, involving matrices of β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), biphasic compositions of both phases and a control group. The physicochemical characterization of materials was carried out by X-Ray diffraction (DRX) and mercury porosimetry. Biodegradability, bioactivity and neoformation processes were investigated by Raman spectroscopy, scanning electron microscopy (SEM) and polarized light conducted on biopsies obtained from in vivo tests for periods of 90 and 180 days. These were performed to evaluate the behavior of granular microporous compositions in relation to bone neoformation. Through the performance obtained from in vivo assays, excellent osseointegration and bone tissue neoformation were observed. The results are encouraging and show that the microporous granular biomaterials of HA, β-TCP and biphasic compositions show similar results with pe...

Research paper thumbnail of Bioactive composites fabricated by freezing-thawing method for bone regeneration applications

Journal of Polymer Science Part B: Polymer Physics, 2015

Bone is often thought be a solid inert material. However, the long bones of the arms and legs are... more Bone is often thought be a solid inert material. However, the long bones of the arms and legs are in fact highly complex tissues which ABSTRACT Hydrogels are widely used for controlled delivery of therapeutic agents. However, hydrogels lack bioactivity to encourage bone formation and required mechanically integrity. Moreover, chemically crosslinking hydrogels exhibits cytotoxic effect. To overcome these issues poly-vinyl alcohol (PVA) and poly-acrylic acid (PAA) blends were utilised as a polymer matrix and were combined with a ceramic materials consists of βTCP, Wollastonite and Magnesium silicate. The final 3D construct was physically crosslinked using various freeze thawing (F/T) cycles. The final composite were characterized by FTIR, SEM, swelling and rheometry. Antimicrobial activity containing ciprofloxacin was tested against a pathogen associated with osteomyelitis. FTIR and SEM analysis illustrated that ceramics were dispersed within the composite and improved the hydrogen bonds of these hydrogels which had a porous morphology. Swelling studies in buffer solution pH 7.4 showed an increase in polymer swelling when ceramic was added. However, rheological testing demonstrated that incorporation of ceramics caused an increase in mechanical properties. DSC thermograms showed increased Tg values for samples containing ceramics. Antimicrobial activity tests presented positive results with ciprofloxacin. The combination of increased strength and ability to encapsulate a clinically relevant antimicrobial agent indicates that the composite tested in this study has potential for the treatment of osteomyelitis.

Research paper thumbnail of Different in vitro behavior of two Ca3(PO4)2 based biomaterials, a glass-ceramic and a ceramic, having the same chemical composition

Boletín de la Sociedad Española de Cerámica y Vidrio, 2015

b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 4 (2 0 ... more b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 4 (2 0 1 5) 181-188

Research paper thumbnail of Calcium Phosphates in Biomedical Engineering

In this article a review of the use of Calcium phosphates in Biomedical Engineering has been done... more In this article a review of the use of Calcium phosphates in Biomedical Engineering has been done. A brief revision of the first applications in the field of medicine of these phosphates is carried out, to later comment on the current situation. The different types of existing calcium phosphates are summarized and where they are applied in the field of biomedicine. Likewise, the latest advances in its processing and its applications are discussed. The properties that these materials have to show in order to predict their behavior when used as biomaterials are also reviewed. Finally, the future of these materials and their applications is described

Research paper thumbnail of Self-Photopolymerizable Hydrogel–Ceramic Composites with Scavenger Properties

Polymers, 2022

The photocatalytic behaviours of semiconductive ceramic nanoparticles such as TiO2, ZnO, Fe2O3, a... more The photocatalytic behaviours of semiconductive ceramic nanoparticles such as TiO2, ZnO, Fe2O3, and Fe3O4, have been extensively studied in photocatalysis and photopolymerization, due to their ability to produce radical species under ultraviolet–visible light, and even in dark conditions. In addition, in the form of microparticles, TiO2 and its Magnéli phases are capable of neutralizing radical species, and a heterogeneous catalytic process has been suggested to explain this property, as it is well known as scavenging activity. Thus, in this study, we demonstrate that these ceramic powders, in the form of microparticles, could be used as photoinitiators in UV polymerization in order to synthesize a hydrogel matrix. Them, embedded ceramic powders could be able to neutralize radical species of physiological media once implanted. The hydrogel matrix would regulate the exchange of free radicals in any media, while the ceramic particles would neutralize the reactive species. Therefore, i...

Research paper thumbnail of Synchrotron X-ray microdiffraction to study dental structures in Cretaceous crocodylomorphs

Cretaceous Research, 2021

Synchrotron radiation X-ray microdiffraction (SR-mXRD) has been applied for the first time as a f... more Synchrotron radiation X-ray microdiffraction (SR-mXRD) has been applied for the first time as a fundamental method of analysis to unveil crocodilian teeth growth and development. Teeth from a fossil crocodylomorph from the Upper Cretaceous site of Lo Hueco (Spain) and a modern crocodylian from the living species Crocodylus niloticus have been analysed. Both samples have been studied through Polarized Light Microscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy, Confocal Raman Spectroscopy, and SR-mXRD. Significant differences have been found in hydroxyapatite (HA) crystallite sizes and texture, and the evolution of these two features along teeth depth. The main differences observed in crystallite size are related to postdepositional processes and/or the environmental and functional pressures of teeth during crocodylomorph life, very different from that of the modern specimen. Regarding the crystalline texture in the tooth enamel, it can be linked to teeth functionality during crocodilian life, causing the directed growth of HA crystallites due to the mechanical stress to which they are subjected.

Research paper thumbnail of Novel Osteoinductive and Osteogenic Scaffolds of Monetite, Amorphous Calcium Phosphate, Hydroxyapatite, and Silica Gel: Influence of the Hydroxyapatite/Monetite Ratio on Their In Vivo Behavior and on Their Physical and Chemical Properties

ACS Biomaterials Science & Engineering, 2020

Research paper thumbnail of Composite cryogels for dual drug delivery and enhanced mechanical properties

Polymer Composites, 2017

In this study, we present a simple and effective process that integrates hydrogels with drugs + c... more In this study, we present a simple and effective process that integrates hydrogels with drugs + ceramics via physical crosslinks resulting in improved mechanical properties. These cryogels have the potential for controlled drug release and stimulus responsive behaviour. The hydrogels were produced from polyvinyl alcohol and polyacrylic acid by varying the molecular weight of the polymers, via freeze thawing technique. The cryogels were combined with two ceramics: (1) a combination of beta-tricalcium phosphate, wollastonite, magnesium silicate and (2)titanium dioxide nanopowder. Theophylline, a model drug, was incorporated into the structure to analyse the drug release behaviour. A layered structure was produced by adding both hydrogels + ceramics into a mould where a polyvinyl alcohol dried film acted as a barrier and reinforcing structure. The results showed that the barrier integrated between both hydrogels by a physically crosslinking mechanism. This adhesion was demonstrated using Fourier transform infrared spectroscopy and scanning electron microscopy. Swelling of this composite showed the profile of drug release from both hydrogels + ceramics while simultaneously releasing the drug independently without diffusing via the opposite layer. Finally, mechanical properties were improved with the addition of the ceramics, which demonstrates the potential approach in terms of modification of weak hydrogel systems.

Research paper thumbnail of Processing of hydroxyapatite obtained by combustion synthesis

Boletín de la Sociedad Española de Cerámica y Vidrio, 2017

One of the reasons of implants failure is the stress forces appearing in the material-tissue inte... more One of the reasons of implants failure is the stress forces appearing in the material-tissue interface due to the differences between their mechanical properties. For this reason, similar mechanical properties to the surrounding tissue are desirable. The synthesis of hydroxyapatite by solution combustion method and its processing have been studied in order to obtain fully dense ceramic bodies with improved mechanical strength. Combustion synthesis provides nanostructured powders characterized by a high surface area to facilitate the following sintering. Moreover, synthesis was conducted in aqueous and oxidizing media. Oxidizing media improve homogenization and increase the energy released during combustion. It gives rise to particles whose morphology and sizes suggest lower surface energies compared with aqueous media. Obtained powders were sintered by using a controlled sintering rate schedule. Lower surfaces energies minimize the shrinkage during sintering and relative densities measurements and diametral compression test confirm improved densification and consequently mechanical properties.

Research paper thumbnail of External and internal ontogenetic changes in the first rib

American Journal of Physical Anthropology, 2017

Research paper thumbnail of Calcium phosphates for biomedical applications

Boletín de la Sociedad Española de Cerámica y Vidrio, 2017

b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 6 (2 0 ... more b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 6 (2 0 1 7) 91-112

Research paper thumbnail of An in vivo study on bone formation behavior of microporous granular calcium phosphate

Biomaterials science, Jan 9, 2017

This study was developed based on in vivo investigation of microporous granular biomaterials base... more This study was developed based on in vivo investigation of microporous granular biomaterials based on calcium phosphates, involving matrices of β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), biphasic compositions of both phases and a control group. The physicochemical characterization of materials was carried out by X-Ray diffraction (DRX) and mercury porosimetry. Biodegradability, bioactivity and neoformation processes were investigated by Raman spectroscopy, scanning electron microscopy (SEM) and polarized light conducted on biopsies obtained from in vivo tests for periods of 90 and 180 days. These were performed to evaluate the behavior of granular microporous compositions in relation to bone neoformation. Through the performance obtained from in vivo assays, excellent osseointegration and bone tissue neoformation were observed. The results are encouraging and show that the microporous granular biomaterials of HA, β-TCP and biphasic compositions show similar results with pe...

Research paper thumbnail of Bioactive composites fabricated by freezing-thawing method for bone regeneration applications

Journal of Polymer Science Part B: Polymer Physics, 2015

Bone is often thought be a solid inert material. However, the long bones of the arms and legs are... more Bone is often thought be a solid inert material. However, the long bones of the arms and legs are in fact highly complex tissues which ABSTRACT Hydrogels are widely used for controlled delivery of therapeutic agents. However, hydrogels lack bioactivity to encourage bone formation and required mechanically integrity. Moreover, chemically crosslinking hydrogels exhibits cytotoxic effect. To overcome these issues poly-vinyl alcohol (PVA) and poly-acrylic acid (PAA) blends were utilised as a polymer matrix and were combined with a ceramic materials consists of βTCP, Wollastonite and Magnesium silicate. The final 3D construct was physically crosslinked using various freeze thawing (F/T) cycles. The final composite were characterized by FTIR, SEM, swelling and rheometry. Antimicrobial activity containing ciprofloxacin was tested against a pathogen associated with osteomyelitis. FTIR and SEM analysis illustrated that ceramics were dispersed within the composite and improved the hydrogen bonds of these hydrogels which had a porous morphology. Swelling studies in buffer solution pH 7.4 showed an increase in polymer swelling when ceramic was added. However, rheological testing demonstrated that incorporation of ceramics caused an increase in mechanical properties. DSC thermograms showed increased Tg values for samples containing ceramics. Antimicrobial activity tests presented positive results with ciprofloxacin. The combination of increased strength and ability to encapsulate a clinically relevant antimicrobial agent indicates that the composite tested in this study has potential for the treatment of osteomyelitis.

Research paper thumbnail of Different in vitro behavior of two Ca3(PO4)2 based biomaterials, a glass-ceramic and a ceramic, having the same chemical composition

Boletín de la Sociedad Española de Cerámica y Vidrio, 2015

b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 4 (2 0 ... more b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o 5 4 (2 0 1 5) 181-188

Research paper thumbnail of Calcium Phosphates in Biomedical Engineering

In this article a review of the use of Calcium phosphates in Biomedical Engineering has been done... more In this article a review of the use of Calcium phosphates in Biomedical Engineering has been done. A brief revision of the first applications in the field of medicine of these phosphates is carried out, to later comment on the current situation. The different types of existing calcium phosphates are summarized and where they are applied in the field of biomedicine. Likewise, the latest advances in its processing and its applications are discussed. The properties that these materials have to show in order to predict their behavior when used as biomaterials are also reviewed. Finally, the future of these materials and their applications is described