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Electrophoretic coatings of hydroxyapatite with various nanocrystal shapes
Patel, Kapil D.,Singh, Rajendra K.,Lee, Jung-Hwan,Kim, Hae-Won Elsevier 2019 Materials letters Vol.234 No.-
<P><B>Abstract</B></P> <P>Bioactive nanostructured coating has been a key strategy to improve the cell adhesion and osseointegration of metallic implants. This study presents the electrophoretic coatings of hydroxyapatite with tunable nanocrystal morphologies. The hydroxyapatite nanocrystals were prepared with three different elongated dimensions by the hydrothermal method (∼80 nm; SHA, ∼300 nm; MHA, and ∼900 nm; LHA), which were used in combination with a fugitive biopolymer chitosan for the electrophoretic deposition on titanium. All the HA coatings were densely and homogeneously deposited and had different and unique nanotopologies and corresponding surface areas. The coating parameter significantly altered the cell behaviors including anchorage, spreading and proliferation; the cell adhesion was better on the small- and middle-sized nanocrystals (SHA, MHA > LHA), which was interestingly opposite in cell spreading (LHA > SHA, MHA), and then the cell proliferation was again up-regulated on SHA and MHA. Although more studies are needed to elucidate the biological phenomenon, the sets of results imply the importance of tailored nanocrystal morphology in the initial (adhesion and growth) cellular events.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Various nanocrystal shapes of HA were prepared by hydrothermal process. </LI> <LI> The synthesized HA’s crystals were used for EPD to produce nanostructured coatings. </LI> <LI> The rMSC viability on SHA coatings was higher that MHA and LHA coatings. </LI> <LI> MHA coatings showed higher cell adhesion compare to SHA and LHA (MHA > SHA > LHA). </LI> <LI> MHA coatings showed higher spreading compare to SHA and LHA at 12 and 24 h. </LI> </UL> </P>
Patel, Kapil D.,El-Fiqi, Ahmed,Lee, Hye-Young,Singh, Rajendra K.,Kim, Dong-Ae,Lee, Hae-Hyoung,Kim, Hae-Won The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.47
<P>Nanocomposites with bone-bioactivity and drug eluting capacity are considered as potentially valuable coating materials for metallic bone implants. Here, we developed composite coatings of chitosan (CH)–bioactive glass nanoparticles (BGn) <I>via</I> cathodic electrophoretic deposition (EPD). BGn 50–100 nm in size with aminated surface were suspended with CH molecules at different ratios (5–20 wt% BGn) in aqueous medium, and EPD was performed. Uniform coatings with thicknesses of a few to tens of micrometers were produced, which was controllable by the EPD parameters (voltage, pH and time). Thermogravimetric analysis revealed the quantity of BGn within the coatings that well corresponded to that initially incorporated. Apatite forming ability of the coatings, performed in simulated body fluid, was significantly improved by the addition of BGn. Degradation of the coatings increased with increasing BGn addition. Of note, the degradation profile was almost linear with time; degradation of 5–13 wt% during 1 week became 30–40 wt% after 7 weeks at almost a constant rate. The CH–BGn coatings showed favorable cell adhesion and growth, and stimulated osteogenic differentiation. Drug loading and release capacity of the CH–BGn coatings were performed using the ampicillin antibiotic as a model drug. Ampicillin, initially incorporated within the CH–BGn suspension, was eluted from the coatings continuously over 10–11 weeks, confirming long-term drug delivering capacity. Antibacterial tests also confirmed the effects of released ampicillin using agar diffusion assay against <I>Streptococcus mutants</I>. The CH–BGn may be potentially useful as a coating composition for metallic implants due to the excellent bone bioactivity and cell responses, as well as the capacity for long-term drug delivery.</P> <P>Graphic Abstract</P><P>Chitosan–nanobioactive glass composites with bone-bioactivity and drug eluting capacity are potentially valuable coatings for metallic bone implants. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm33830k'> </P>
Patel, Kapil D.,Kim, Tae-Hyun,Lee, Eun-Jung,Han, Cheol-Min,Lee, Ja-Yeon,Singh, Rajendra K.,Kim, Hae-Won American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.22
<P>Exploring the biological interfaces of metallic implants has been an important issue in achieving biofunctional success. Here we develop a biointerface with nanotopological features and bioactive composition, comprising a carbon nanotube (CNT) and chitosan (Chi) hybrid, via an electrophoretic deposition (EPD). The physicochemical properties, in vitro biocompatibility, and protein delivering capacity of the decorated nanohybrid layer were investigated, to address its potential usefulness as bone regenerating implants. Over a wide compositional range, the nanostructured hybrid interfaces were successfully formed with varying thicknesses, depending on the electrodeposition parameters. CNT-Chi hybrid interfaces showed a time-sequenced degradation in saline water, and a rapid induction of hydroxyapatite mineral in a simulated body fluid. The nanostructured hybrid substrates stimulated the initial adhesion events of the osteoblastic cells, including cell adhesion rate, spreading behaviors, and expression of adhesive proteins. The nanostructured hybrid interfaces significantly improved the adsorption of protein molecules, which was enabled by the surface charge interaction, and increased surface area of the nanotopology. Furthermore, the incorporated protein was released at a highly sustained rate, profiling a diffusion-controlled pattern over a couple of weeks, suggesting the possible usefulness as a protein delivery device. Collectively, the nanostructured hybrid CNT-Chi layer, implemented by an electrodeposition, is considered a biocompatible, cell-stimulating, and protein-delivering biointerface of metallic implants.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-22/am505759p/production/images/medium/am-2014-05759p_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am505759p'>ACS Electronic Supporting Info</A></P>
Progress in Nanotheranostics Based on Mesoporous Silica Nanomaterial Platforms
Singh, Rajendra K.,Patel, Kapil D.,Leong, Kam W.,Kim, Hae-Won American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.12
<P>Theranostics based on nanoparticles (NPs) is a promising paradigm in nanomedicine. Mesoporous silica nanoparticle (MSN)-based systems offer unique characteristics to enable multimodal imaging or simultaneous diagnosis and therapy. They include large surface area and volume, tunable pore size, functionalizable surface, and acceptable biological safety. Hybridization with other NPs and chemical modification can further potentiate the multifunctionality of MSN-based systems toward translation. Here, we update the recent progress on MSN-based systems for theranostic purposes. We discuss various synthetic approaches used to construct the theranostic platforms either via intrinsic chemistry or extrinsic combination. These include defect generation in the silica structure, encapsulation of diagnostic NPs within silica, their assembly on the silica surface, and direct conjugation of dye chemicals. Collectively, in vitro and in vivo results demonstrate that multimodal imaging capacities can be integrated with the therapeutic functions of these MSN systems for therapy. With further improvement in bioimaging sensitivity and targeting specificity, the multifunctional MSN-based theranostic systems will find many clinical applications in the near future.</P>
Singh, Rajendra K.,Patel, Kapil D.,Mahapatra, Chinmaya,Kang, Min Sil,Kim, Hae-Won American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.37
<P>Biocompatible nanomaterials that allow for labeling cells and tissues with the capacity to load and deliver drug molecules hold great promise for the therapeutic-diagnostic purposes in tissue repair and disease cure. Here,a novel nanoplatform, called C-dot Bioactive organosilica nanosphere (C-BON), is introduced to have excellent theranostic potential, such as controlled 'drug delivery., visible-light imaging, and NIR photothermal activity. C-dots with a few nanometers were in situ generated in the Ca-containing organosilica mesoporous nanospheres through the sol-gel and thermal-treatment processes. The C-BON exhibited multicolor luminescence over a wide visible-light range with Strong emissions and high photostability over time and against acidity and the possible in vivo optical imaging capacity when injected in rat subcutaneous tissues. Moreover, the C-BON showed a photothermal heating effect upon the irradiation of near-infrared. The C-BON) thanks to the high mesoporoSity and existence of Ca2+ ions,demonstrated excellent loading capacity of anticancer drug doxorubicin (as high as 90% of carrier weight), and long-term (over a couple of weeks) and pH/NIR-dependent release ability. The C-BON preserved the compositional merit of Ca-Si glass, having excellent bioactivity and tell compatibility in vitro. Taken all, the multifunctional properties of C-BON-multicolor luminescence, photothermal activity, and high drug loading and controlled release together with its excellent bioactivity and cell compatibility potentiate the future applications' in theranostics (chemotherapy and photothermal therapy with optical imaging).</P>