ELECTROHYDRODYNAMIC PROCESSING OF CALCIUM PHOSPHATES: COATING AND PATTERNING FOR MEDICAL IMPLANTS

Nano LIFE ◽  
2012 ◽  
Vol 02 (01) ◽  
pp. 1250008 ◽  
Author(s):  
GILLIAN MUNIR ◽  
JIE HUANG ◽  
MOHAN EDIRISINGHE ◽  
RAFIQUE NANGREJO ◽  
WILLIAM BONFIELD
Keyword(s):  
Surface Topography ◽  
Cellular Response ◽  
Cell Attachment ◽  
Calcium Phosphates ◽  
Life Time ◽  
Medical Implants ◽  
Osteoblast Cells ◽  
Ha Coating ◽  
Electrohydrodynamic Atomization

Hydroxyapatite (HA)-coated metallic prostheses, which combine the osteoconductivity of HA and high strength of metallic alloys, have been increasingly the choice of joint replacement prostheses by surgeons as the general population lives longer. Surface modification of metallic implant surfaces is one of the key focal points to implantation technology. In addition to material chemistry, surface topography has been found to positively impact cellular response and is able to enhance the life time of the implant. Recently, a new technique, template-assisted electrohydrodynamic atomization (TAEA) spraying, developed using the principles of electrohydrodynamic atomization spraying, which is an electrically driven jet-based deposition method, is of considerable interest in surface topography formation. The process offers the attractive advantages of compatibility with micro-fabrication technology and versatility in pattern specification for advanced implant designs. This technology incorporates nanosized calcium phosphate to mimic the size and chemical composition of bone mineral in a micrometer-dimension pattern configuration to guide cellular responses. In vitro studies showed that both pillar and track nano Silicon-substituted HA (SiHA) patterns were able to encourage the attachment and growth of osteoblast cells, the track patterns provided the favourite surface for the initial cell attachment while a fast cell proliferation rate was found on the pillar pattern from day 1 to day 5 in comparison with that of a SiHA-coated surface. The alignment of actin cytoskeleton of osteoblast cells matched the orientation of the entire cell. The shear peel strength of the patterned interlocking nano-HA coating was found to be at least an order of magnitude higher than the conventional HA coating. Therefore, TAEA offers great potential for producing new coatings with a tailored surface topography, on both the micro- and nano-scale in a more cost effective way to enhance the performance of medical implants.

scholarly journals A rapid, parasite-dependent cellular response to Dirofilaria immitis in the Mongolian jird (Meriones unguiculatus)

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Christopher C. Evans ◽  
Katherine M. Day ◽  
Yi Chu ◽  
Bridget Garner ◽  
Kaori Sakamoto ◽  
...  
Keyword(s):  
Cellular Response ◽  
Dirofilaria Immitis ◽  
Cell Attachment ◽  
Early Response ◽  
Meriones Unguiculatus ◽  
Filarial Parasite ◽  
Immune Mediated ◽  
Secretory Products ◽  
Species Specific

Abstract Background The Mongolian jird (Meriones unguiculatus) has long been recognized as a permissive host for the filarial parasite Brugia malayi; however, it is nonpermissive to another filarial parasite, canine heartworm (Dirofilaria immitis). By elucidating differences in the early response to infection, we sought to identify mechanisms involved in the species-specific clearance of these parasites. We hypothesized that the early clearance of D. immitis in intraperitoneal infection of the jird is immune mediated and parasite species dependent. Methods Jird peritoneal exudate cells (PECs) were isolated and their attachment to parasite larvae assessed in vitro under various conditions: D. immitis and B. malayi cultured separately, co-culture of both parasites, incubation before addition of cells, culture of heat-killed parasites, and culture with PECs isolated from jirds with mature B. malayi infection. The cells attaching to larvae were identified by immunohistochemistry. Results In vitro cell attachment to live D. immitis was high (mean = 99.6%) while much lower for B. malayi (mean = 5.56%). This species-specific attachment was also observed when both filarial species were co-cultured, with no significant change from controls (U(9, 14) = 58.5, p = 0.999). When we replicated these experiments with PECs derived from jirds subcutaneously infected with B. malayi, the results were similar (99.4% and 4.72% of D. immitis and B. malayi, respectively, exhibited cell attachment). Heat-killing the parasites significantly reduced cell attachment to D. immitis (mean = 71.9%; U(11, 14) = 7.5, p < 0.001) while increasing attachment to B. malayi (mean = 16.7%; U(9, 15) = 20, p = 0.002). Cell attachment to both species was reduced when larvae were allowed a 24-h pre-incubation period prior to the addition of cells. The attaching cells were identified as macrophages by immunohistochemistry. Conclusions These results suggest a strongly species-dependent response from which B. malayi could not confer protection by proxy in co-culture. The changes in cell attachment following heat-killing and pre-incubation suggest a role for excretory/secretory products in host immune evasion and/or antigenicity. The nature of this attachment is the subject of ongoing study and may provide insight into filarial host specificity.

In vitro study on the response of RAW264.7 and MS-5 fibroblast cells on laser-induced periodic surface structures for stainless steel alloys

RSC Advances ◽  
2015 ◽  
Vol 5 (53) ◽  
pp. 42548-42558 ◽  
Author(s):  
Clare McDaniel ◽  
Olga Gladkovskaya ◽  
Aiden Flanagan ◽  
Yury Rochev ◽  
Gerard M. O'Connor
Keyword(s):  
Stainless Steel ◽  
Surface Topography ◽  
Cell Attachment ◽  
In Vitro Study ◽  
Surface Structures ◽  
Fibroblast Cells ◽  
Steel Alloys ◽  
Periodic Surface ◽  
Stent Surface

Cell attachment and growth can be controlled by stent surface topography. In some cases fibroblast cells attach while monocytes failed on the structured surface of Pt:SS and 316LSS stents.

scholarly journals Bio-Compatible Processing of LENSTM DepositedCo-Cr-W alloy for Medical Applications

2018 ◽  
Vol 7 (2.20) ◽  
pp. 362 ◽  
Author(s):  
Ganzi Suresh ◽  
K L Narayana ◽  
M Kedar Mallik
Keyword(s):  
Chronic Toxicity ◽  
Motor Vehicle ◽  
Experimental Period ◽  
Layer By Layer ◽  
Medical Implants ◽  
Osteoblast Cells ◽  
Acceptable Result ◽  
Vehicle Accidents

Developing a Medicinal implants or devices is a challenging task for the researchers, right from the selection of materials, design, bio-compatibility and implantation to the host tissue. At every stage it requires proper care in processing of medical implants. In recent years the demand for medical implants had grown rapidly due to the awareness in the society. Major share of implants is used by younger people as they are active in sports, motor vehicle accidents leads to facture. Even older people also preferring to implants for ease of living. The commonly used implants are, prosthetic joints, knee replacement, dental, maxillofacial reconstructions etc.There is huge demand for the medical implants in coming years, presently a few bio-materials available for implant devices such as Ti-alloys, Stainless steel and Co-Cr-Mo alloys. There a scope to the researchers to develop a new alloy that are bio-compatible in nature and bring down the cost of the implant procedure to the needed patients. In this context additive manufacturing (AM) is an advanced manufacturing technology emerging as prominent technique in medical fields. Laser Engineered Net ShapingTM (LENS) is one such metal additive technique which provides fabrication of parts with the help of laser power, melts the powder alloy completely and builds parts layer by layer directly from the CAD model.In the present study, samples are fabricated from LENS process and carried the In-Vitro and In -Vivo bio-compatible tests as cytotoxicity and sub chronic toxicity to verify the toxicants release and their sustainability as the medical implants by the LENS deposited Co-Cr-W alloy samples. From the studies it is observed that the alloy samples show acceptable result. MTT assay demonstrate that cell viability is better in Osteoblast cells compared to the Fibroblast cells. Osteoblast cells show slightly more viable to the cell treatment on the samples during the experimental period. Sub chronic toxicity conclude that LENS deposited Co-Cr-W alloy is not toxic in all the rats studied herein and did not produce any toxic signs or evident symptoms. LENS deposited Co-Cr-W alloy did not cause any lethality or produce any relative body organs weight and haematological studies didn’t show adverse effects.  

Thin Degradable Coatings for Optimization of Osteointegration Associated with Simultaneous Infection Prophylaxis

2016 ◽  
Vol 696 ◽  
pp. 171-176
Author(s):  
Anke Bernstein ◽  
Norbert Suedkamp ◽  
Hermann Otto Mayr ◽  
Rainer Gadow ◽  
Irina Arhire ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Cell Attachment ◽  
Calcium Phosphates ◽  
Thermal Spraying ◽  
In Vitro Cytotoxicity ◽  
Laser Scanning Microscopy ◽  
Cellular Growth ◽  
Flame Spraying ◽  
Infection Prophylaxis

The colonization of biomaterials with bacteria represents the main cause of implant-associated infections. Both an antibiotic prophylaxis and a faster osteointegration can be obtained by incorporation of bactericidal active metals in degradable CaP coatings. At present there is no reliable method on the basis of thermal spraying to get thin homogeneous layers containing silver, copper and bismuth in bacteriostatic / bactericidal concentrations. The aim of the study was the development and optimization of high-velocity suspension flame spraying (HVSFS) process for producing thin resorbable bioactive ceramics coatings on the basis of degradable calcium phosphates. In these layers the bacteriostatic / bactericidal effective metal copper should be integrated. Cells were grown on the materials for 3, 7, 14, and 21 days. Live/dead assay was used to measure cell viability. The in vitro cytotoxicity was determined by the microculture tetrazolium (WST) assay. Cell morphology, cell attachment, and cell spreading were investigated using laser scanning microscopy and raster scanning electron microscopy. All substrates supported sufficient cellular growth for 21 days and showed no cytotoxicity. On each material an identical cell colonisation of well communicating, polygonal, vital cells was verified

scholarly journals Production of High Silicon-Doped Hydroxyapatite Thin Film Coatings via Magnetron Sputtering: Deposition, Characterisation, and In Vitro Biocompatibility

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 190 ◽  
Author(s):  
Samuel C. Coe ◽  
Matthew D. Wadge ◽  
Reda M. Felfel ◽  
Ifty Ahmed ◽  
Gavin S. Walker ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Silicon Content ◽  
Cellular Response ◽  
Cell Attachment ◽  
Initial Response ◽  
Weight Percent ◽  
Hydroxyl Groups

In recent years, it has been found that small weight percent additions of silicon to HA can be used to enhance the initial response between bone tissue and HA. A large amount of research has been concerned with bulk materials, however, only recently has the attention moved to the use of these doped materials as coatings. This paper focusses on the development of a co-RF and pulsed DC magnetron sputtering methodology to produce a high percentage Si containing HA (SiHA) thin films (from 1.8 to 13.4 wt.%; one of the highest recorded in the literature to date). As deposited thin films were found to be amorphous, but crystallised at different annealing temperatures employed, dependent on silicon content, which also lowered surface energy profiles destabilising the films. X-ray photoelectron spectroscopy (XPS) was used to explore the structure of silicon within the films which were found to be in a polymeric (SiO2; Q4) state. However, after annealing, the films transformed to a SiO44−, Q0, state, indicating that silicon had substituted into the HA lattice at higher concentrations than previously reported. A loss of hydroxyl groups and the maintenance of a single-phase HA crystal structure further provided evidence for silicon substitution. Furthermore, a human osteoblast cell (HOB) model was used to explore the in vitro cellular response. The cells appeared to prefer the HA surfaces compared to SiHA surfaces, which was thought to be due to the higher solubility of SiHA surfaces inhibiting protein mediated cell attachment. The extent of this effect was found to be dependent on film crystallinity and silicon content.

In Situ Characterization of Degradation Behavior of Plasma-Sprayed Coatings on Orthopedic and Dental Implants

2006 ◽  
Vol 49 ◽  
pp. 203-211 ◽  
Author(s):  
Racquel Z. LeGeros ◽  
John P. LeGeros
Keyword(s):  
Calcium Phosphate ◽  
Dental Implants ◽  
Calcium Phosphates ◽  
Interfacial Strength ◽  
Precipitation Method ◽  
Calcium Phosphate Coating ◽  
Implant Surface ◽  
Ha Coating ◽  
Plasma Sprayed

Plasma-sprayed ‘HA’ coatings on commercial orthopedic and dental implants were developed to combine the strength of the metal (Ti or Ti alloy) and the bioactivity of the hydroxyapatite (HA). Several studies have shown that ‘HA’-coated implants provided greater amount of bone attachment, higher bone-implant interfacial strength and accelerated skeletal attachment. However, some reports on implant failures have been attributed to coating delamination and coating early resorption of the plasma sprayed ‘HA’ coating. This paper reviews studies on characterization and degradation of plasma-sprayed ‘HA’ coatings on orthopedic and dental implants and offers alternatives to plasma-spray method of providing calcium phosphate coating. X-ray diffraction analyses showed that plasma-sprayed HA coating consists principally of HA and amorphous calcium phosphate (ACP) with minor amounts of other resorbable calcium phosphates (α- or β-tricalcium phosphates, tetracalcium phosphate), sometimes calcium oxide. The HA/ACP ratios were found to range from 20HA/80ACP to 70HA/30ACP in coated implants from different manufacturers. In vitro initial dissolution rates in acidic buffer (pH 6, 37oC) increased with decreasing HA/ACP ratios in the coating because of the preferential dissolution of the ACP phase. These results suggest that coating with very low HA/ACP ratio may result in the premature resorption of the coating before the bone can attach to the implant thus causing loosening and eventual failure of the implant. Alternatives to plasma-sprayed ‘HA’ are implant surface modifications and low temperature calcium phosphate coatings using electrochemical deposition method or precipitation method.

scholarly journals Stable sol–gel hydroxyapatite coating on zirconia dental implant for improved osseointegration

2021 ◽  
Vol 32 (7) ◽  
Author(s):  
Jinyoung Kim ◽  
In-Gu Kang ◽  
Kwang-Hee Cheon ◽  
Sungmi Lee ◽  
Suhyung Park ◽  
...  
Keyword(s):  
Dental Implant ◽  
Cell Attachment ◽  
Sol Gel ◽  
Animal Experiments ◽  
Nanoporous Structure ◽  
Ha Coating ◽  
Implant Material ◽  
Varied Temperature

AbstractAside from being known for its excellent mechanical properties and aesthetic effect, zirconia has recently attracted attention as a new dental implant material. Many studies have focused on hydroxyapatite (HA) coating for obtaining improved biocompatibility, however the coating stability was reduced by a byproduct produced during the high-temperature sintering process. In this study, to overcome this problem, we simply coated the zirconia surface with a sol–gel-derived hydroxyapatite (HA) layer and then sintered it at a varied temperature (<1000 °C). The surface showed a nanoporous structure, and there was no crystalline phase other than HA and zirconia when the sintering temperature was 800 °C. The adhesion strength of the HA layer (>40 MPa) was also appropriate as a dental implant application. In addition, in vitro cell experiments using a preosteoblast cell line revealed that the HA-coated zirconia surface acts as a preferable surface for cell attachment and proliferation than bare zirconia surface. In vivo animal experiments also demonstrated that the osteoconductivity of zirconia were dramatically enhanced by HA coating, which was comparable to that of Ti implant. These results suggest that the sol–gel-based HA-coated zirconia has a great potential for use as a dental implant material.

scholarly journals Development, Characterization and In Vitro Biological Properties of Scaffolds Fabricated From Calcium Phosphate Nanoparticles

2019 ◽  
Vol 20 (7) ◽  
pp. 1790 ◽  
Author(s):  
Lizette Morejón ◽  
José Angel Delgado ◽  
Alexandre Antunes Ribeiro ◽  
Marize Varella de Oliveira ◽  
Eduardo Mendizábal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mineral Composition ◽  
Cell Attachment ◽  
Sintering Temperature ◽  
Calcium Phosphates ◽  
Total Porosity ◽  
Biological Properties ◽  
Solid Content ◽  
Native Bone

Ceramic materials mimic the mineral composition of native bone and feature osteoconductive properties; they are therefore used to regenerate bone tissue. Much research focuses on increasing the porosity and pore interconnectivity of ceramic scaffolds to increase osteoconductivity, cell migration and cell-cell interaction. We aimed to fabricate biocompatible 3D-scaffolds featuring macro- and microporous calcium phosphates with high pore interconnection. Nanoparticles of hydroxyapatite (HA) and calcium deficient hydroxyapatite (CDHA) were synthesized by wet chemical precipitation. Scaffolds were produced from them by the replication polymeric foam technique. Solid content and sintering temperature were varied. Nanoparticles and scaffolds were characterized regarding morphology, chemical and mineral composition, porosity and mechanical properties. Biocompatibility, cell attachment and distribution were evaluated in vitro with human adipose mesenchymal stem cells. Scaffolds with total porosity of 71%–87%, pores in the range of 280–550 µm and connectivity density up to 43 mm−3 were obtained. Smaller pore sizes were obtained at higher sintering temperature. High solid content resulted in a decrease of total porosity but increased interconnectivity. Scaffolds 50HA/50β-TCP featured superior interconnectivity and mechanical properties. They were bioactive and biocompatible. High HA solid content (40 wt.%) in the HA pure scaffolds was negative for cell viability and proliferation, while in the 50HA/50β-TCP composite scaffolds it resulted more biocompatible.

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