•We report the deposition by MAPLE of biomimetic apatite coatings on Ti substrates.•This is the first report of MAPLE deposition of hydrated biomimetic apatite films.•Biomimetic apatite powder was ...synthesized by double decomposition process.•Non-apatitic environments, of high surface reactivity, are preserved post-deposition.•We got the MAPLE complete transfer as thin film of a hydrated, delicate material.
We report the deposition by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique of biomimetic nanocrystalline apatite coatings on titanium substrates, with potential application in tissue engineering. The targets were prepared from metastable, nanometric, poorly crystalline apatite powders, analogous to mineral bone, synthesized through a biomimetic approach by double decomposition process. For the deposition of thin films, a KrF* excimer laser source was used (λ=248nm, τFWHM≤25ns). The analyses revealed the existence, in synthesized powders, of labile non-apatitic mineral ions, associated with the formation of a hydrated layer at the surface of the nanocrystals. The thin film analyses showed that the structural and chemical nature of the nanocrystalline apatite was prevalently preserved. The perpetuation of the non-apatitic environments was also observed. The study indicated that MAPLE is a suitable technique for the congruent transfer of a delicate material, such as the biomimetic hydrated nanohydroxyapatite.
► We deposit PDLLA/gentamicin composite thin films by MAPLE. ► MAPLE deposition process does not cause significant changes of biopolymer chemical structure. ► Composite thin films effectively inhibit ...Staphylococcus aureus growth. ► MAPLE can be used to produce antimicrobial implantable medical devices.
We report on thin film deposition by matrix assisted pulsed laser evaporation (MAPLE) of two polymer–drug composite thin film systems. A pulsed KrF* excimer laser source (λ=248nm, τ=25ns, ν=10Hz) was used to deposit composite thin films of poly(d,l-lactide) (PDLLA) containing several gentamicin concentrations. FTIR spectroscopy was used to demonstrate that MAPLE-transferred materials exhibited chemical structures similar to those of drop cast materials. Scanning electron microscopy data indicated that MAPLE may be used to fabricate thin films of good morphological quality. The activity of PDLLA–gentamicin composite thin films against Staphylococcus aureus bacteria was demonstrated using drop testing. The influence of drug concentration on microbial viability was also assessed. Our studies indicate that polymer–drug composite thin films prepared by MAPLE may be used to impart antimicrobial activity to implants, medical devices, and other contact surfaces.
The aim of this study was to obtain biomimetic inorganic–organic thin films as coatings for metallic medical implants. These contain hydroxyapatite, the inorganic component of the bony tissues, and a ...natural biopolymer – silk fibroin – added in view to induce the surface functionalization. Hydroxyapatite (HA), silk fibroin (FIB) and composite HA–FIB films were obtained by Matrix Assisted Pulsed Laser Evaporation (MAPLE) in order to compare their physical and biological performances as coatings on metallic prostheses. We used an excimer laser source (KrF*,
λ
=
248
nm,
τ
=
25
ns) operated at 10
Hz repetition rate. Coatings were deposited on quartz, Si and Ti substrates and then subjected to physical (FTIR, XRD, AFM, SEM) analyses, correlated with the results of the cytocompatibility
in vitro tests. The hybrid films were synthesized from frozen targets of aqueous suspensions with 3:2 or 3:4 weight ratio of HA:FIB. An appropriate stoichiometric and functional transfer was obtained for 0.4–0.5
J/cm
2 laser fluence. FTIR spectra of FIB and HA–FIB films exhibited distinctive absorption maxima, in specific positions of FIB random coil form: 1540
cm
−1 amide II, 1654
cm
−1 amide I, 1243
cm
−1 amide III, while the peak from 1027
cm
−1 appeared only for HA and composite films. Osteosarcoma SaOs2 cells cultured 72
h on FIB and HA–FIB films showed increased viability, good spreading and normal cell morphology. The well-elongated, flattened cells are a sign of an appropriate interaction with the MAPLE FIB and composite HA–FIB coatings.
We extended for the first time pulsed laser ablation to the deposition of octacalcium phosphate Ca
8H
2(PO
4)
6·5H
2O (OCP) thin films. The depositions were performed with a pulsed UV laser source (
...λ=248
nm,
τ⩾20
ns) in a flux of hot water vapors. The targets were sintered from crystalline OCP powder and the laser ablation fluence was set at values of 1.5–2
J/cm
2. During depositions the collectors, Si or Ti substrates, were maintained at a constant temperature within the range 20–200°C. The resulting structures were submitted to heat treatment in hot water vapors for up to 6
h. The best results were obtained at a substrate temperature of 150°C during both deposition and post-deposition treatment. High-resolution electron microscopy and XRD at grazing incidence indicated that the coatings obtained were made of nanocrystalline OCP. Cross-section TEM investigations showed that the coatings contained droplets stacked on Ti substrates as well as distributed across the entire thickness of the arborescence-like structure layers. The results of WST-1 assay, cell adherence, DNA replication, and caspase-1 activity confirmed the good biocompatibility of the coatings.
Functionalized implants represent an advanced approaching in implantology, aiming to improve the biointegration and the long-term success of surgical procedures. We report on the synthesis of ...hydroxyapatite (HA) thin films on polymethylmetacrylate (PMMA) substrates – used as cranio-spinal implant-type structures – by two alternative methods: pulsed laser deposition (PLD) and radio-frequency magnetron sputtering (MS). The deposition parameters were optimized in order to avoid the substrate overheating. Stoichiometric HA structures were obtained by PLD with incident laser fluences of 1.4–2.75
J/cm
2, pressures of 30–46.66
Pa and 10
Hz pulses repetition rate. The MS depositions were performed at constant pressure of 0.3
Pa in inert and reactive atmospheres. SEM-EDS, XRD, FTIR and pull-out measurements were performed assessing the apatitic-type structure of the prepared films along with their satisfactory mechanical adhesion. Cell viability, proliferation and adhesion tests in osteosarcoma SaOs2 cell cultures were performed to validate the bioactive behaviour of the structures and to select the most favourable deposition regimes. For PLD, this requires a low fluence of 1.4
J/cm
2, reduced pressure of water vapours and a 100
°C/4
h thermal treatment. For MS, the best results were obtained for 80% Ar
+
20% O
2 reactive atmosphere at low RF power (∼75
W). Cells grown on these coatings exhibit behaviour similar to those grown on the standard borosilicate glass control: increased viability, good proliferation, and optimal cell adhesion. In vitro tests proved that HA/PMMA neurosurgical structures prepared by PLD and MS are compatible for the interaction with human bone cells.
We review the progress made by us using pulsed laser deposition (PLD) of two bioactive calcium phosphates: octacalcium phosphate (OCP) and Mn doped carbonated hydroxyapatite (Mn-CHA). Coatings of ...these materials well suited for biomimetic medical prostheses and pivots were synthesized on titanium substrates with a pulsed KrF* UV laser source.
The best deposition conditions for Mn-CHA thin films were 13
Pa O
2, 400
°C with post heat treatment of 6
h in air enriched with water vapours. The coatings are stoichiometric and crystalline. For OCP, deposition at 150
°C in 50
Pa water vapor atmosphere, post treated by 6
h annealing in hot flux of water vapours, resulted in stoichiometric, but poorly-crystallized films.
Degradation tests show different behavior for the OCP and Mn-CHA coatings. In vitro cell growth shows excellent adherence and biocompatibility of osteoblasts and fibroblasts in both OCP and Mn-CHA coatings. Human osteoblasts display normal proliferation and viability, and good differentiation behaviour.
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