Medical Potentialities of Biomimetic Apatites through Adsorption, Ionic Substitution, and Mineral/Organic Associations: Three Illustrative Examples

Al-Kattan, Ahmed; Errassifi, Farid; Sautereau, Anne-Marie; Sarda, Stéphanie; Dufour, Pascal; Barroug, Allal; Santos, Isabelle Dos; Combes, Christèle; Grossin, David; Rey, Christian; Drouet, Christophe

doi:10.1002/adem.200980084

Cited by 40 publications

(43 citation statements)

References 35 publications

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“…The affinity of nanoparticle binding was found to be several orders of magnitude higher than the affinity of several bisphosphonates (BP) to hydroxyapatite. Adsorption capacities of BP 58–62 were comparable to those of nanoparticles, which implies that nanoparticles bind more rapidly, a characteristic important for topical treatments, but at comparable maximal amounts to BP. The reported b max and K a of BP, which are known to have exceptionally high affinity to hydroxyapatite, are within the range of 2.17–2.31 μ mol/m 2 and 1–3470 L-mmol −158–64 , similar to the characteristics of the nanoparticles described herein.…”

Section: Resultsmentioning

confidence: 83%

pH-Activated Nanoparticles for Controlled Topical Delivery of Farnesol To Disrupt Oral Biofilm Virulence

et al. 2015

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Development of effective therapies to control oral biofilms is challenging, as topically introduced agents must avoid rapid clearance from biofilm-tooth interfaces while targeting biofilm microenvironments. Additionally, exopolysaccharide matrix and acidification of biofilm microenvironments are associated with cariogenic (caries-producing) biofilm virulence. Thus, nanoparticle carriers capable of binding to hydroxyapatite (HA), saliva-coated HA (sHA), and exopolysaccharides with enhanced drug-release at acidic pH were developed. Nanoparticles are formed from diblock copolymers composed of 2-(dimethylamino)ethyl methacrylate (DMAEMA), butyl methacrylate (BMA), and 2-propylacrylic acid (PAA) (p(DMAEMA)-b-p(DMAEMA-co-BMA-co-PAA)) that self-assemble into ~21 nm cationic nanoparticles. Nanoparticles exhibit outstanding adsorption affinities (~244 L-mmol−1) to negatively-charged HA, sHA, and exopolysaccharide-coated sHA due to strong electrostatic interactions via multivalent tertiary amines of p(DMAEMA). Owing to hydrophobic cores, Nanoparticles load farnesol, a hydrophobic antibacterial drug, at ~22 wt%. Farnesol release is pH-dependent with t1/2=7 and 15 h for release at pH 4.5 and 7.2, as Nanoparticles undergo core destabilization at acidic pH, characteristic of cariogenic biofilm microenvironments. Importantly, topical applications of farnesol-loaded nanoparticles disrupted Streptococcus mutans biofilms 4-fold more effectively than free farnesol. Mechanical stability of biofilms treated with drug-loaded nanoparticles was compromised, resulting in >2-fold enhancement in biofilm removal under shear stress compared to free farnesol and controls. Farnesol-loaded nanoparticles effectively attenuated biofilm virulence in vivo using a clinically-relevant topical treatment regimen (2×/day) in a rodent dental caries disease model. Treatment with farnesol-loaded nanoparticles reduced both the number and severity of carious lesions, while free-farnesol had no effect. Nanoparticles have great potential to enhance the efficacy of antibiofilm agents through multi-targeted binding and pH-responsive drug release due to microenvironmental triggers.

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Section: Resultsmentioning

confidence: 83%

pH-Activated Nanoparticles for Controlled Topical Delivery of Farnesol To Disrupt Oral Biofilm Virulence

et al. 2015

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“…Moreover, they present high ion-exchange ability and adsorption capacity. Thus, modified apatites have been investigated not only for biomaterial applications but also as delivery systems for molecules of biological interest such as proteins [5], growth factors [6], and drugs [7], as & Stéphanie Sarda stephanie.sarda@iut-tlse3.fr adsorbents for heavy metals in environmental applications [8], in chromatography column separations systems [9], and as supports for heterogeneous catalysis [10,11]. Covalent grafting of organic groups on solid support is usually carried out by silylation, using functionalised trialkoxysilanes (OR 0 ) 3 SiR.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic characterisation of hydroxyapatite and nanocrystalline apatite with grafted aminopropyltriethoxysilane: nature of silane–surface interaction

et al. 2015

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Heterogenised homogeneous catalysis is commonly performed with molecular catalysts grafted on solids via adsorption or via a covalent molecular link. Covalent grafting of organic groups on solid supports is usually carried out by silylation, using functionalised trialkoxysilanes. Among these solids supports, very few studies have been published on apatites. In the present work, aminopropyltriethoxysilane (APTES) grafting was performed in toluene on different apatitic supports: crystallised stoichiometric hydroxyapatites differing by the drying method, freeze-dried (HAP) and dried at 100°C (HAPD), and a nanocrystalline apatite. All materials were fully characterised, before and after grafting, for better understanding of the nature of the alkoxysilane/surface interaction. The data show a clear competition between the covalent grafting of APTES and its polycondensation reaction, depending on the nature of the solid support surface. Silylation is accompanied by APTES covalent grafting to oxygen atom of the hydroxyl groups of the apatitic structure and/or of the OH -species that are present on the surface hydrated layer. This work clarifies the nature of silane grafting onto selected apatitic surfaces and especially the influence of the composition and properties of the apatitic surfaces on the process of silylation.

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“…These surface ions were also shown to be easily "exchangeable" in solution with ions from the surrounding medium [11,14,15], leading to very peculiar surface properties [16]. Also, surface ions play a primordial role in adsorption mechanisms [17,18]. In the field of bone repair materials, these characteristics are important for the interactions between apatite-based implants and the biological environment of implantation.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of nucleotides on biomimetic apatite: The case of adenosine 5′ monophosphate (AMP)

Hammami

Elfeki

Marsan

et al. 2015

Applied Surface Science

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Highlights The interaction between the AMP nucleotide and a biomimetic apatite was investigated  Data fitted to a Sips isotherm with parameters suggesting adsorptive cooperativity  Enhanced adsorption was pointed out in acidic conditions  AMP Raman band shifts/enhancements were noticed, indicative of chemical interaction ABSTRACTThis work investigates the interaction between the nucleotide adenosine 5' monophosphate molecule (AMP) and a biomimetic nanocrystalline carbonated apatite as a model for bone mineral. The analogy of the apatite phase used in this work with biological apatite was first pointed out by complementary techniques. AMP adsorption isotherms were then investigated. Obtained data were fitted to a Sips isotherm with an exponent greater than one suggesting positive cooperativity among adsorbed molecules. The data were compared to a previous study relative to the adsorption of another nucleotide, cytidine monophosphate (CMP) onto a similar substrate, evidencing some effect of the chemical nature of the nucleic base. An enhanced adsorption was observed under acidic (pH 6) conditions as opposed to pH 7.4, which parallels the case of DNA adsorption on biomimetic apatite. An estimated standard Gibbs free energy associated to the adsorption process (G°a ds  -22 kJ/mol) intermediate between "physisorption" and "chemisorption" was found. The analysis of the solids after adsorption pointed to the preservation of the main characteristics of the apatite substrate but shifts or enhancements of Raman bands attributed to AMP showed the existence of chemical interactions involving both the phosphate and adenine parts of AMP. This contribution adds to the works conducted in view of better understanding the interaction of DNA/RNA and their constitutive nucleotides and the surface of biomimetic apatites. It could prove helpful in disciplines such as bone diagenesis (DNA/apatite interface in aged bones) or nanomedicine (setup of DNA-or RNA-loaded apatite systems). Also, the adsorption of nucleic acids on minerals like apatites could have played a role in the preservation of such biomolecules in the varying conditions known to exist at the origin of life on Earth, underlining the importance of dedicated adsorption studies.

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Medical Potentialities of Biomimetic Apatites through Adsorption, Ionic Substitution, and Mineral/Organic Associations: Three Illustrative Examples

Cited by 40 publications

References 35 publications

pH-Activated Nanoparticles for Controlled Topical Delivery of Farnesol To Disrupt Oral Biofilm Virulence

pH-Activated Nanoparticles for Controlled Topical Delivery of Farnesol To Disrupt Oral Biofilm Virulence

Spectroscopic characterisation of hydroxyapatite and nanocrystalline apatite with grafted aminopropyltriethoxysilane: nature of silane–surface interaction

Adsorption of nucleotides on biomimetic apatite: The case of adenosine 5′ monophosphate (AMP)

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