References of "Luyten, Jan"
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See detailEffect of DOPA and dopamine coupling on protein loading of hydroxyapatite
Ozhukil Kollath, Vinayaraj ULg; Mullens, Steven; Luyten, Jan et al

in Materials Technology: Advanced Performance Materials (2016)

Hydroxyapatite (HA) is a promising carrier material for oral delivery of biomolecules such as proteins and drugs. Ways to increase the loading of such molecules on HA will lead to better nanomedicine ... [more ▼]

Hydroxyapatite (HA) is a promising carrier material for oral delivery of biomolecules such as proteins and drugs. Ways to increase the loading of such molecules on HA will lead to better nanomedicine. This study reports the surface functionalisation of HA particles using the mussel inspired molecules dopamine (DA) and 3,4-dihydroxy-L-phenylalanine (DOPA), in order to increase protein loading. The adsorption mechanisms are discussed based on the adsorption isotherms, zeta potential, thermal analysis and theoretical models. Results show that DA functionalisation enhanced the loading, while DOPA functionalisation was ineffective. [less ▲]

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See detailElectrophoretic deposition of hydroxyapatite and hydroxyapatite– alginate on rapid prototyped 3D Ti6Al4V scaffolds
Ozhukil Kollath, Vinayaraj; Chen, Qiang; Mullens, Steven et al

in Journal of Materials Science (2016), 51

The advantage of using bioceramic particles coated on porous three-dimensional structures is still unexplored in the purpose of improving the osteoinduction of hybrid metallic scaffold implants in vivo ... [more ▼]

The advantage of using bioceramic particles coated on porous three-dimensional structures is still unexplored in the purpose of improving the osteoinduction of hybrid metallic scaffold implants in vivo. In this study, we evaluate electrophoretic deposition (EPD) to coat porous Ti6Al4V scaffolds with hydroxyapatite (HA). Scaffolds were shaped in different open structures with a horizontal shift in fiber stacking. They were produced using three-dimensional fiber deposition method and were coated by EPD with HA powder (d10 = 1.7, d50 = 5.7 and d90 = 18 lm) suspended in ethanol or butanol at different concentration, DC voltage, and time. A composite HA–alginate was also used to coat the scaffolds. Alginate was used as a binder, and the coating properties (homogeneity, thickness, cracks, continuity, etc.) were compared to coatings obtained from pure HA suspensions. Voltage and time of deposition effects were studied between 10 and 140 V and 10 and 120 s, respectively. Coating thickness and density with respect to the depth of the porous structure were studied by observing cross sections using scanning electron microscopy and image processing analysis. HA–alginate combination resulted in a homogeneous and deeper dense layer of HA. This work also points to the characteristics of HA–alginate composite as a superior alternative to pure HA coating which needs an appropriate thermal treatment for adequate substrate adhesion. [less ▲]

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See detailA Modular Approach To Study Protein Adsorption on Surface Modified Hydroxyapatite
Ozhukil Kollath, Vinayaraj ULg; Van den Broeck, Freya; Fehér, Krisztina et al

in Chemistry : A European Journal (2015), 21(29), 10497-10505

Biocompatible inorganic nano- and microcarriers can be suitable candidates for protein delivery. This study demonstrates facile methods of functionalization by using nanoscale linker molecules to change ... [more ▼]

Biocompatible inorganic nano- and microcarriers can be suitable candidates for protein delivery. This study demonstrates facile methods of functionalization by using nanoscale linker molecules to change the protein adsorption capacity of hydroxyapatite (HA) powder. The adsorption capacity of bovine serum albumin as a model protein has been studied with respect to the surface modifications. The selected linker molecules (lysine, arginine, and phosphoserine) can influence the adsorption capacity by changing the electrostatic nature of the HA surface. Qualitative and quantitative analyses of linker-molecule interactions with the HA surface have been performed by using NMR spectroscopy, zeta-potential measurements, X-ray photoelectron spectroscopy, and thermogravimetric analyses. Additionally, correlations to theoretical isotherm models have been calculated with respect to Langmuir and Freundlich isotherms. Lysine and arginine increased the protein adsorption, whereas phosphoserine reduced the protein adsorption. The results show that the adsorption capacity can be controlled with different functionalization, depending on the protein–carrier selections under consideration. The scientific knowledge acquired from this study can be applied in various biotechnological applications that involve biomolecule–inorganic material interfaces. [less ▲]

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See detailProtein-calcium phosphate nanocomposites: Benchmarking protein loading via physical and chemical modifications against co-precipitation
Ozhukil Kollath, Vinayaraj ULg; Mullens, Steven; Luyten, Jan et al

in RSC Advances (2015), 5

The low protein loading capacity of commercially available calcium phosphate (CaP) is a major impediment in effectively using this inorganic material as a protein carrier despite its recognized ... [more ▼]

The low protein loading capacity of commercially available calcium phosphate (CaP) is a major impediment in effectively using this inorganic material as a protein carrier despite its recognized biocompatibility. In this study, nanocomposites of CaP and BSA were prepared by carefully designed precipitation methods in aqueous media. In the first co-precipitation method (CaP-BSA-1), calcium and phosphate precursors were simultaneously added to the protein solution matrix and in the second method (CaP-BSA-2) the protein solution was added after the reaction of the precursors. Crystallinity and phase composition of the resulting powders were determined using X-ray diffraction technique. Qualitative confirmation of presence of BSA on the nanocomposites, was obtained using mass spectrometry, ATR-FTIR and XPS. The results from desorption and thermogravimetric measurements indicated that BSA was trapped inside the cavities in the case of CaP-BSA- 1 whereas it was mostly surface adsorbed in the case of CaP-BSA-2. Protein loading capacity of these composites was compared with various physical and chemical surface modification strategies used on commercially available calcium phosphate powders. Nanocomposite particulates were found to have about 275 % higher protein loading capacity as compared to a commercial CaP powder with same surface area. Overall, this study benchmarks the different techniques used for protein loading enhancement on inorganic materials. [less ▲]

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See detailAtmospheric Pressure Plasma as an Activation Step for Improving Protein Adsorption on Hydroxyapatite Powder
Ozhukil Kollath, Vinayaraj ULg; Put, Sofie; Mullens, Steven et al

in Plasma Processes and Polymers (2015)

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See detailAC vs. DC electrophoretic deposition of hydroxyapatite on titanium
Ozhukil Kollath, Vinayaraj ULg; Chen, Qiang; Closset, Raphaël ULg et al

in Journal of the European Ceramic Society (2013), 33(13-14), 27152721

In this study, electrophoretic deposition (EPD) of hydroxyapatite (HA) powder on titanium plate was performed using butanol as solvent under direct current (DC) and alternating current (AC) fields. The ... [more ▼]

In this study, electrophoretic deposition (EPD) of hydroxyapatite (HA) powder on titanium plate was performed using butanol as solvent under direct current (DC) and alternating current (AC) fields. The zeta potential of the suspensions was measured to define their stability and the charge on the particles. Coating thickness was varied by adjusting the voltage and time of deposition. Surface morphology and cross section thickness were studied using scanning electron microscopy and image analysis software. Surface crack density was calculated from the micrographs. The results showed that the samples of similar thickness have higher grain density when coated using AC as compared to DC EPD. This facile but novel test proves the capability of AC-EPD to attain denser and uniform HA coatings from non-aqueous medium. [less ▲]

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See detailSystematic processing of β – tricalcium phosphate for efficient protein loading and in vitro analysis of antigen uptake
Ozhukil Kollath, Vinayaraj ULg; De Geest, Bruno; Mullens, Steven et al

in Advanced Engineering Materials (2013), 15(4), 295-301

Microparticulate calcium phosphate (CaP) powders are promising drug carriers because of their biocompatibility and degradability under physiological conditions. The adsorption capability of CaP ... [more ▼]

Microparticulate calcium phosphate (CaP) powders are promising drug carriers because of their biocompatibility and degradability under physiological conditions. The adsorption capability of CaP microparticles makes them interesting candidates, within the inorganic carrier materials, for delivering protein antigens to professional antigen presenting cells (APC) for vaccination purpose. However, in order to bind and deliver a sufficient amount of protein, the challenge is to effectively increase the binding capacity of this material. In this study, b-tricalcium phosphate (b-TCP) powder is engineered to obtain microparticles with increased protein loading, using bovine serum albumin as a model antigen. The decrease in particle size and increase in specific surface area of carrier is shown to strongly affect protein adsorption. Finally, we demonstrate that the processed b-TCP is capable of delivering its protein payload in vitro to dendritic cells, which are professional APCs and the target cell population for microparticulate vaccines. [less ▲]

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See detailREVIEW: CONCERNS OF FORCE SPECTROSCOPY USING ATOMIC FORCE MICROSCOPY
Ozhukil Kollath, Vinayaraj ULg; Vinck, Evi; Karl, Traina et al

Report (2012)

Atomic force microscopy (AFM) and its various applications helped many industries for characterisation of materials. One of such field is the biomaterial research where biocompatibility of implant ... [more ▼]

Atomic force microscopy (AFM) and its various applications helped many industries for characterisation of materials. One of such field is the biomaterial research where biocompatibility of implant materials is the main question. Force spectroscopy, one of the AFM technique helps to find the interaction between individual molecules in a non-destructive manner and hence helps to find the biocompatibility. Through this report, we try to review the principles and major concerns of force spectroscopy method of AFM. [less ▲]

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