Christophe Drouet

Université de Toulouse · CIRIMAT

Amorphous calcium phosphates (ACPs) represent a family of bioactive compounds particularly relevant to bone regeneration. However, due to their intrinsic metastability, their processing into 3D-shaped materials cannot be undergone by conventional sintering methods and requires cold sintering approaches. Also, their microstructure and local composit...

Layered Double Hydroxides (LDH) are relevant inorganic materials for biomedical application thanks to both their tunable chemical composition and their lamellar structure allowing molecules or ions intercalation in the interlayer spaces. However, their brittleness and thermal sensibility limit the fabrication of 3D materials based on LDH, making it...

A large amount of research in orthopedic and maxillofacial domains is dedicated to the development of bioactive 3D scaffolds. This includes the search for highly resorbable compounds, capable of triggering cell activity and favoring bone regeneration. Considering the phosphocalcic nature of bone mineral, these aims can be achieved by the choice of...

Hybrid organic–inorganic bio‐inspired apatite nanoparticles (NPs) are attractive for biomedical applications and especially in nanomedicine. Unfortunately, their applications in nanomedicine are limited by their broad particle size distributions and uncontrolled drug loading due to their multistep synthesis process. Besides, very few attempts at ex...

Bone repair is a major challenge in regenerative medicine, e.g. for large defects. There is a need for bioactive, highly percolating bone substitutes favoring bone ingrowth and tissue healing. Here, a modern 3D printing approach (VAT photopolymerization) was exploited to fabricate hydroxyapatite (HA) scaffolds with a Gyroid-"Triply periodic minimal...

Layered Double Hydroxides (LDHs) are inorganic compounds of relevance to various domains, where their surface reactivity and/or intercalation capacities can be advantageously exploited for the retention/release of ionic and molecular species. In this study, we have explored specifically the applicability in the field of bone regeneration of one LDH...

Critical bone defect repair remains a major medical challenge. Developing biocompatible materials with bone-healing ability is a key field of research, and calcium-deficient apatites (CDA) are appealing bioactive candidates. We previously described a method to cover activated carbon cloths (ACC) with CDA or strontium-doped CDA coatings to generate...

Peri-implant infection is rapidly becoming an – if not the most – important clinical challenge for indwelling medical devices. To alleviate the global rise in antibiotic use for the treatment of such infections, a plethora of biomaterials/bioengineering-based antimicrobial strategies are emerging to restrict or ideally to eliminate microbial adhesi...

Epoxy-amine systems are ubiquitous in the field of industrial thermosetting polymers, often used in a moist atmosphere. In addition, previous studies showed amine-metal interactions through the formation of an interphase, with the formation of surface complexes that may involve the formation of water molecules. However, to date, the impact of water...

Biomimetic nanocrystalline apatites analogous to bone mineral can be prepared using soft chemistry. Due to their high similarity to bone apatite, as opposed to stoichiometric hydroxyapatite for example, they now represent an appealing class of compounds to produce bioactive ceramics for which drug delivery and ion exchange abilities have been descr...

Biomimetic apatites exhibit a high reactivity allowing ion substitutions to modulate their in vivo response. We developed a novel approach combining several bioactive ions in a spatially controlled way in view of subsequent releases to address the sequence of events occurring after implantation, including potential microorganisms’ colonization. Inn...

Biphasic macroporous Hydroxyapatite/β-Tricalcium Phosphate (HA/β-TCP) scaffolds (BCPs) are widely used for bone repair. However, the high-temperature HA and β-TCP phases exhibit limited bioactivity (low solubility of HA, restricted surface area, low ion release). Strategies were developed to coat such BCPs with biomimetic apatite to enhance bioacti...

Bone infections are a key health challenge with dramatic consequences for affected patients. In dentistry, periodontitis is a medically compromised condition for efficient dental care and bone grafting, the success of which depends on whether the surgical site is infected or not. Present treatments involve antibiotics associated with massive bacter...

In addition to designing catalytic materials ever more active and selective, the emergence of new classes of greener catalysts remains very challenging. The apatite family system with hydroxyapatite (HA) structure appears as a good candidate for catalysis due to its eco‐compatibility properties, its sorption ability toward organic molecules, and it...

Jahnsites/whiteites are a large family of phosphate hydrate minerals of relevance to terrestrial and martian mineralogy. It was recently hypothesized as being present in Gale Crater sediments from XRD analyses performed by the CheMin analyzer aboard the Curiosity rover. However, the conditions of formation and thermodynamic properties of these comp...

Flax fibers are particularly relevant in composite fabrication due to natural availability and mechanical properties close to glass fibers. We explore flax fiber-containing epoxy-amine (DGEBA/DETA) polymers with wide industrial applicability. Flax fibers impact the glass transition temperature (DSC), with a Tg drop of 67 °C at 30 wt% loading. For d...

Layered double hydroxides (LDHs) are key inorganic compounds relevant to a wealth of applicative purposes, by exploiting their layered structure allowing for ion/molecular sequestration or release. However, a technological barrier exists in the fabrication of cohesive LDH monoliths in link with their metastability. In this work, a series of cohesiv...

The SuperCam instrument, onboard the Perseverance rover (Mars 2020 mission) is designed to perform remote analysis on the Martian surface employing several spectroscopic techniques such as Laser Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman (TRR), Time-Resolved Fluorescence (TRF) and Visible and Infrared (VISIR) reflectance. In additio...

The Perseverance rover is exploring Jezero crater on Mars since February 2021. SuperCam instrument is part of the scientific payload, combining five different techniques in order to characterize the targets to sample: LIBS (Laser-Induced Breakdown Spectroscopy), Raman and Visible and Infrared (VISIR) spectroscopies, Sound Recording and a colored Im...

A biomaterial that is both bioactive and capable of controlled drug release is highly attractive for bone regeneration. In previous works, we demonstrated the possibility of combining activated carbon fiber cloth (ACC) and biomimetic apatite (such as calcium-deficient hydroxyapatite (CDA)) to develop an efficient material for bone regeneration. The...

Using continuous and time-resolved spectroscopy, we investigate Raman and luminescence signals from synthetic hydroxylapatites doped with trivalent REE including Dy3+, Eu3+, Nd3+, and Sm3+, as well as REE in natural apatites, with laser excitations at 532 and 785 nm. We demonstrate that time-resolved spectroscopy is an efficient method to reduce lu...

Aims: Osteosarcoma represents the second most common cause of death in children and young adults. No biomaterial allowing local drug delivery has been specifically developed. However, a biocompatible bioactive implantable material could prevent some amputations, and the local release of an antitumor agent could limit risks of relapse and metastasis...

Citation: Al-Kattan, A.; Grojo, D.; Drouet, C.; Mouskeftaras, A.; Delaporte, P.; Casanova, A.; Robin, J.D.; Magdinier, F.; Alloncle, P.; Constantinescu, C.; et al. Short-Pulse Lasers: A Versatile Tool in Creating Novel Nano-/Micro-Structures and Compositional Analysis for Healthcare and Wellbeing Challenges. Nanomaterials 2021, 11, 712. https://

Among thermosetting polymers, epoxy resins are major components of adhesives, sealants, paints and composites. Polymerization is often achieved by reaction of epoxy monomers like DGEBA with amine hardeners such as DETA. Previous works showed that polyamines interact with metal (hydr/oxide) substrates leading to the formation of an interphase involv...

SuperCam is a highly integrated remote-sensing instrumental suite for NASA’s Mars 2020 mission. It consists of a co-aligned combination of Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), Visible and Infrared Spectroscopy (VISIR), together with sound recording (MIC) and high-magnification imaging techniques...

Epoxy resins are ubiquitously encountered in industrial applications as in adhesives and composites. The properties of epoxy-amine networks are directly impacted by the presence of metal (hydr-oxidized) surfaces, leading to a modification of their glass transition temperature Tg. We propose here an innovative experimental approach, investigating th...

Dicalcium phosphate dihydrate, DCPD (CaHPO4·2H2O), brushite, is an important calcium phosphate compound encountered in mineralized tissues and used in medicine, especially in bone cement formulations. However, the use of DCPD as direct implantable biomaterial has not received dedicated attention. In addition, the possibility to dope DCPD with biolo...

Most treatments of skin pathologies involve local administration of active agents. One issue can however be the partial transcutaneous diffusion of the drug to blood circulation, leading to undesirable effects. In this work, the original use of submicron mineral particles based on bio-inspired calcium phosphate apatite was explored for the first ti...

Calcium phosphate apatites are naturally present in all vertebrates, as a biomineral in teeth and bones. The possibility to prepare synthetic analogs in close-to-physiological conditions allows the development of bio-inspired materials for medical use. While apatite-based biomaterials are extensively developed for bone regeneration, their intrinsic...

Calcium phosphates (CaP) represent a major class of biominerals present in living organisms. Considering the high biocompatibility and tailorable reactivity/resorbability of these compounds, strategies are developed to prepare synthetic bio-inspired ceramics for biomedical applications such as bone substitution and regeneration, but also in other e...

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In the field of bone regeneration, some clinical conditions require highly-resorbable, reactive bone substitutes to rapidly initiate tissue neo-formation. In this view, Amorphous Calcium Phosphates (ACP) appear as well suited bioceramics taking into account their high metastability. However, the metastability also leads to difficulties of sintering...

Calcium phosphates (CaP) such as biomimetic nanocrystalline apatite or amorphous calcium phosphate are hydrated bioactive compounds particularly suitable for bone repair applications due to their similarity with bone mineral. However, their consolidation in ceramic parts deserves special attention as they are thermodynamically metastable and can de...

Calcium is an essential component of osteogenesis and is often required for imparting significant bioactivity to synthetic bone substitutes and in particular silicate-based materials. However, the mechanism of calcium incorporation inside sol-gel silicates is poorly understood. In this work, we shed light on the determinant parameters for incorpora...

Some compositional and structural features of mature bone mineral particles remain unclear. They have been described as calcium-deficient and hydroxyl-deficient carbonated hydroxyapatite particles in which a fraction of the PO43− lattice sites are occupied by HPO42− ions. The time has come to revise this description since it has now been proven tha...

Biocompatible nanosystems exhibiting long-lifetime (∼millisecond) luminescence features are particularly relevant in the field of bioimaging. In this study, citrate-functionalized calcium-doped europium phosphates nanophosphors of the rhabdophane type were prepared at different synthesis times by a bioinspired crystallization route, consisting in t...

Nanocrystalline apatites mimicking bone mineral represent a versatile platform for biomedical applications thanks to their similarity to bone apatite and the possibility to (multi)functionalize them so as to provide “à la carte” properties. One relevant domain is in particular oncology, where drug-loaded biomaterials and engineered nanosystems may...

Bone is a natural nanocomposite. Its mineral component is nanocrystalline calcium phosphate apatite, whose synthetic biomimetic analogs can be prepared by wet chemistry. The initially formed crystals, whether biological or synthetic, exhibit very peculiar physicochemical features. In particular, they are nanocrystalline, nonstoichiometric, and hydr...

Various carbonated calcium phosphate powders were synthesized by aqueous precipitation and ceramics consolidation by spark plasma sintering (SPS) at very low temperature was investigated. The objective was to preserve low crystallinity and avoid material decarbonation. SPS at low temperature only leads to little or no sintering when crystallized po...

Nanomedicine covers the application of nanotechnologies in medicine. Of particular interest is the setup of highly-cytocompatible nanoparticles for use as drug carriers and/or for medical imaging. In this context, luminescent nanoparticles are appealing nanodevices with great potential for imaging of tumor or other targetable cells, and several str...

The chapter discusses the physical–chemical properties of calcium phosphates (Ca-P), among the most used bioactive ceramics. The main calcium phosphate compounds are presented with a brief description of their synthesis methods, their characterization, using different techniques, including chemical analyzes, X-ray diffraction, Fourier transform inf...

The repair of large bone defects is a major clinical problem for which tissue engineering (association of a biomaterial and cells) constitutes a valuable alternative. In this domain, the architecture and the mechanical properties of the 3D scaffold aimed to support cells is of key importance to succeed in bone reconstruction. In this study, we aim...

Hydroxyapatite (HAp) was known as a bone implant material due to its biocompatibility, bioactive, chemical stability and its compositional similarity to natural bone. In this work nanocrystalline HAp coatings were prepared on 316L stainless steel (316LSS) substrates using a potentio-dynamic method (potential scanning in the range from 0 to −1.6 V/S...

Cryopreservation of red blood cells (RBC) is an important method for maintaining an inventory of rare RBC units and managing special transfusion circumstances. Currently, in a clinical setting, glycerol is used as cryoprotectant against freezing damage. After thawing and before transfusion, glycerol must however be removed to avoid intravascular he...

Laser induced breakdown spectroscopy (LIBS), as performed by the ChemCam instrument, provides a new technique to measure hydrogen at the surface of Mars. Using a laboratory replica of the LIBS instrument onboard the Curiosity rover, different types of hydrated samples (basalts, calcium and magnesium sulfates, opals and apatites) covering a range of...

The nanometer-sized plate-like morphology of bone mineral is necessary for proper bone mechanics and physiology. However, mechanisms regulating the morphology of these mineral nanocrystals remain unclear. The dominant hypothesis attributes the size and shape regulation to organic-mineral interactions. Here, we present data supporting the hypothesis...

Biomimetic nanocrystalline apatites are analogous to bone mineral. They can be exploited not only for bone regeneration applications, but it is also possible to take advantage of their biomimetic features to explore novel domains of research such as in nanomedicine, if the nanoparticles are stabilized as a colloidal formulation. In this contributio...

This contribution gathers various examples illustrating the fact that nanocrystalline apatites represent a genuine multi-functionalizable platform for a wide range of biomedical applications. It is indeed possible to convey additional functionalities to the already appealing properties of biomimetic apatites, via appropriate ionic substitutions and...

Hydroxyapatite (HAp) coatings were prepared on Ti6Al4V substrate by electrodeposition method from electrolyte solution containing Ca(NO3)2, NH4H2PO4 and NaNO3. The results show that the HAp coatings were single phase crystals of HAp. Scanning electron microscope (SEM) images present that HAp/Ti6Al4V have flake shapes which arrange to form like-cora...

This work proposes to combine tranexamic acid (TAX), a clinically used antifibrinolytic agent, and hydroxyapatite (HA), widely used in bone replacement, to produce a novel bioactive apatitic biomaterial with intrinsic hemostatic properties. The aim of this study was to investigate adsorptive behavior of the TAX molecule onto HA and to point out its...

This contribution investigates the interaction of two types of biomimetic-apatite colloidal nanoparticles (negatively-charged 47nm, and positively-charged 190nm NPs) with blood components, namely red blood cells (RBC) and plasma proteins, with the view to inspect their hemocompatibility. The NPs, preliminarily characterized by XRD, FTIR and DLS, sh...