Rodríguez-Lorenzo, Luis M.; Fernández, M.; Parra, J.; Vázquez Lasa, Blanca; López-Bravo, A.; San Román, Julio; Gross, K. A.; Anderson, Gail I.
Bisphosphonates (BP) are drugs currently administered orally to treat diseases
characterised by an excessive bone resorption. Alternative and more efficient delivery routes and
more potent compounds are being investigated. Three implantable delivery systems, which allow
the controlled release of therapeutic agents from the device core, are examined in this paper. (4-
(aminomethyl) benzene) bisphosphonic acid (ABBP) was incorporated on
Ca8.8Na0.8(PO4)4.8(CO3)1.2(OH)0.4F1.6 particles by refluxing the powder in a 60 mmol suspension in
acetone at 60ºC for 5 hours. 4-aminophenyl acetic bisphosphonate monosodium salt (APBP) and 1-
H-indole-3-acetic bisphosphonate monosodium (IBP) were loaded on Ca10(PO4)6(OH)1F1 ceramic
bodies by stirring the ceramic bodies in 0.04M BP solutions. Injectable acrylic cements based...
Rodríguez-Lorenzo, Luis M.; Vázquez Lasa, Blanca; San Román, Julio; Gross, K. A.
Bisphosphonates (BPs) may play an important role in minimizing osteolysis. In this work
two new bisphosphonates pertaining to second and third generations respectively, have been
synthesized and incorporated onto a chemically enriched hydroxyapatite. BP synthesis has been
performed by adding H3PO3, PCl3 and methanesulfonic acid over 4-aminophenyl acetic acid
(APBP) and 1-H-indole-3-acetic acid (IBP) respectively at 65ºC in a N2 atmosphere. These
compounds bear a primary amine group bonded to an aromatic ring, and a secondary amine group
within a heterocyclic ring respectively. A chemically enriched hydroxyapatite with a chemical
content corresponding to a 50% fluorided hydroxyapatite has been synthesized. Ceramic bodies
manufactured by uniaxial pressure followed by...
Vargas-Becerril, N.; Téllez-Jurado, Lucía; Reyes-Gasga, J.; Alvarez-Perez, M. A.; Rodríguez-Lorenzo, Luis M.
Pechini method is a materials synthesis method based on the preparation of a polymeric matrix. The advantage of this method is the ability to obtain materials with different particle sizes depending on the synthesis condition with a homogeneous distribution. In this work, carbonated hydroxyapatite (c-OHAp) nanoparticles were obtained by a modified Pechini method. To obtain the polymeric precursor of the c-OHAp, the polymeric matrix was prepared through a polyesterification reaction between citric acid and ethylene-glycol. Adding calcium hydroxide and ortophosphoric acid in aqueous solutions, raising the temperature up to 140 C/2 h and keeping constant the pH at 8. The...
Volkmer, Tiago; Magalhães, Joana; Sousa, Vania; Santos, Luis A.; Burguera, Elena F.; Blanco, Francisco J.; San Román, Julio; Rodríguez-Lorenzo, Luis M.
The aim of this work is to evaluate the potential of cryogels to be used as scaffolds in tissue engineering. Scaffolds based on the α-tricalcium phosphate reinforced PDMAEMA (Poly(dimethyl aminoethyl methacrylate))/PHEMA (poly(hydroxyethyl methacrylate)) system were prepared and human trabecular bone-derived cells (HTBs) and bone marrow derived-mesenchymal stem cells (BM-MSCs) cultured on them. Several features, such as porosity, pore shape, molecular weight between crosslinks and mesh size, are studied. The most suitable PDMAEMA/PHEMA ratio for cell proliferation has been assessed and the viability, adhesion, proliferation and expression of osteoblastic biochemical markers are evaluated. The PDMAEMA/PHEMA ratio influences the scaffolds porosity. Values...
Rojo, Luis; Radley-Searle, S.; Fernández-Gutiérrez, M.; Rodríguez-Lorenzo, Luis M.; Abradelo, C.; Deb, S.; San Román, Julio
Compounds having the general formula MFO·4H2O where M = Ca or Sr and FO = a folate anion were prepared and their structure and physico-chemical properties were determined by elemental and thermal TGA, DSC analysis, FTIR, and EDAX spectroscopies and DRX. The results indicate that the two compounds form stable structures where folic acid acts as a self-bridging ligand via two bidentate carboxylate groups. Moreover the two compounds showed a low toxicity in vitro response as h-osteoblast cell viability was not negatively affected by the presence of folate derivatives within the range of 0.063-0.5 mg ml-1. The results also indicate...
Bölgen, Nimet; Aguilar, María Rosa; Fernández de Marco, M. del Mar; Gonzalo-Flores, Sandra; Villar Rodil, Silvia; San Román, Julio; Pişkin, Erhan
NIPA and HEMA-lactate-Dextran-based biodegradable and thermoresponsive cryogels were synthesized at different compositions by cryogelation. Chemical and morphological properties of the HEMA-lactate-Dextran-co-NIPA cryogel matrices were demonstrated by FTIR, SEM, and ESEM. Thermoresponsivity of the prepared cryogels was investigated by DSC, imaging NMR, and swelling studies. For possible use of the cryogels in potential bone tissue engineering applications, either hydrophobic simvastatin was embedded, or hydrophilic simvastatin was incorporated in the cryogels. Release profiles of simvastatin delivering cryogel scaffolds depending on their composition, hydrophobicity or hydrophilicity of loaded simvastatin and the medium temperature were demonstrated.
Fernández-Montes, Belén; San Román, Julio; Rodríguez-Lorenzo, Luis M.
Protein-surface interaction may determine the success or failure of an implanted device. Not much attention have been paid to the specific surface parametes of hydroxyapatite (OHAp) that modulates and determines the formation and potential activity of the layer of proteins that is first formed when the material get in contact with the host tissue. the influence of specific surface area (SSA), crystallite size (CS) and particle size (PS) of OHAp on the adsorption of proteins relevant for bone regeneration is evaluated in this article. OHAp have been prepared by a wet chemical reaction of Ca(OH)(2) with H(3) PO(4) . One...
García-Álvarez, Isabel; Doncel-Pérez, Ernesto; García-Junceda, Eduardo; Fernández-Mayoralas, Alfonso; Garrido, Leoncio
Objective: Preparation of functionalized micro- and submicrofibers by electrospinning of polyesters with glycosides which are structural elements of proteoglycans, for application to the repair of spinal cord lesions. Material and methods: Solutions of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with synthetic glycosides were prepared varying systematically the processing conditions. Fiber morphology assessed by scanning electron microscopy. The stability of the interaction between the glycoside and the polymer fiber was evaluated in aqueous medium, and their toxicity in cultures of neural cells. Results: The fiber morphology was altered mainly by the solution parameters. In aqueous medium, the glycoside with a sulfate group was released from fibers...
Torre, M. A.; Rio, E. del; Morales, Enrique
Supercapacitors have attracted great attention in power source applications, due to their high power density, elevated charge/discharge rate, good reversibility and long life. Activated carbons are the most frequently used electrode material, due to their high accessibility, non-toxicity, high chemical stability, good electrical conductivity, high surface area and low cost, but in practice the capacitance values are limited by the material microstructure. In this work we report on the synthesis and electrochemical characterization of carbon/polyaniline composites, synthesized by in-situ polymerization in acid media of aniline monomer on the surface of two activated carbons having different textural properties, and on the...
Michell, Rose Mary; Blaszczyk-Lezak, Iwona; Mijangos, Carmen; Müller, Alejandro J.
We review how confinement from the micron to the nanometer scale can affect nucleation and crystallization of polymers in: droplets, blends, block copolymers and infiltration into alumina nanopores. Confinement can produce fractionated crystallization or exclusive crystallization at much higher supercoolings as compared to bulk polymers, as the degree of confinement increases. For highly confined heterogeneity free micro or nano-domains, overall crystallization kinetics is dominated by nucleation and therefore becomes first order. The nucleation mechanism changes from heterogeneous nucleation for bulk polymers to surface or homogeneous nucleation for ensembles of confined and isolated heterogeneity free micro or nanodomains. Surface nucleation is...
Vargas Becerril, Nancy; Téllez-Jurado, Lucía; Rodríguez-Lorenzo, Luis M.
The purpose of this work is to evaluate how the surface modification of apatites with alendronate may affect the adsorption of proteins relevant for bone regeneration. Two different apatites were synthesized for the study. Both of the powders were obtained by co-precipitation, assisted either by mechanical or by ultrasonic stirring. Hydroxyapatite-alendronate hybrid compounds were obtained by reactive milling and the protein adsorption experiments were done by mixing 10 mg of the hydroxyapatites and hybrids powders with 1.5 mL of a 0.1 mg/mL fibronectin solution. After 24h of digestion and separation of the solid from the liquid, the protein remaining in...
Rodríguez-Lorenzo, Luis M.; Fernández, Mar; Parra, J.; Vázquez Lasa, Blanca
Two bisphosphonates (BPs), namely 1-hydroxy-2-[4-aminophenyl]ethane-1,1-diphosphonic
acid (APBP) and 1-hydroxy-2-[3-indolyl]ethane-1,1-diphosphonic acid (IBP), have
been synthesized and incorporated to acrylic injectable and self-curing formulations. Alendronic
acid monosodium trihydrated salt (ALN) containing cement was formulated as control. These
systems have potential applications in low density hard tissues affected by ailments characterized
by a high osteoclastic resorption, i.e. osteoporosis and osteolysis. Values of curing parameters of
APBP and IBP were acceptable to obtain pastes with enough fluency to be injected through a
biopsy needle into the bone cavity. Working times ranged between 8 and 15 min and maximum
temperature was around 508C. Cured systems stored for a month in synthetic body fluid...