Research Repository :: Browsing by Author "Macha, Innocent J"

Browsing by Author "Macha, Innocent J"

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Adhesion and Scratch Testing of Antibiotic Loaded Poly-Lactic Acid Biocomposite Thin Films on Metallic Implants
(Trans Tech Publications, 2018-10) Karacan, Ipek; Chou, Joshua; Ben-Nissan, Besim; Macha, Innocent J; Juritza, Arion; Wang, Andy H; Muller, Wolfgang H; Grossin, David; Taraschi, Valerio; Oktar, Faik N; Swain, Michael
Surface modifications have been progressively applied in order to improve the mechanical, biological and chemical properties of metallic dental and orthopedic implants. Therefore, the novel and multifunctional biocomposites coating matrices, which also consist of local and targeted drug delivery systems, are the most recent applications in the medical field. In this study, gentamicin antibiotic containing HAp bioceramics were utilized in a biodegradable poly-lactic acid thin film matrix which was applied to Ti6Al4V metallic implant surfaces. Nanoindentation and scratch test methods were applied. It was observed that, bonding between coating and the substrate is strong enough to be used in implant applications. Additionally, it was observed that the hardness and Young's Modulus values of uncoated Ti6Al4V disc were 4.3 and 125.2 GPa, respectively. However, under the same testing conditions, it was also observed that the H values (0.6-0.8GPa) and the E (50-60 GPa) values of PLA-HAp biocomposite coated samples are slightly higher than the H values (0.4-0.6 GPa) and the E values (40-50GPa) of only PLA coated sample.
Advances in Bioglass and Glass Ceramics for Biomedical Applications
(Wiley, 2016-05) Ben-Nissan, Besim; Choi, Andy H.; Macha, Innocent J
Advances in Calcium Phosphate Nanocoatings and Nanocomposites
(Springer, 2013-12) Choi, Andy H.; Ben-Nissan, Besim; Conway, Richard C.; Macha, Innocent J
It is possible by using nanocomposite approach to control the strength and Young’s modulus of the composite to become close to those of human cortical or cancellous bone. This is made possible with the help of secondary substitution phases. Various materials have been applied as biomaterials and tissue regeneration materials, and the in vivo cytotoxicity and biocompatibility have been the main consideration in their use and their long-term success. This chapter aims to give a brief introduction and current applications of calcium phosphate nanocomposites as tissue engineering and as a delivery vehicle for drugs, genes, and proteins. Furthermore, the chapter will also examine the potential use of calcium phosphate nanocomposite coatings for tissue engineering scaffolds.
An Alternative Synthesis Method for Di Calcium Phosphate (Monetite) Powders from Mediterranean Mussel (Mytilus galloprovincialis) Shells
(Springer NATURE, 2013-08) Macha, Innocent J; Ozyegin, Lutfiye S; Chou, Joshua; Samur, Ramazan; Oktar, Faik N; Ben-Nissan, Besim
Marine species, such as corals, sea shells and nacres, attract special interest in bioceramics field for bone graft, bone cements and drug delivery applications. Most of the marine structures are made up of pure calcium carbonate (calcite or aragonite) with a very small amount of an organic matrix. In the past the most common way to transform these structures to hydroxyapatite was hydrothermal transformation method. This current work introduces a new approach for producing fine powders of calcium phosphates from Mediterranean mussel (Mytilus galloprovincialis) shells. A comparative study was carried out to investigate the differences of these powders under only hot plate heating and hot plate heating together with ultrasonic agitation while H3PO4 was added. The temperature of the hotplate was kept constant at 80 oC and then, H3PO4 was added drop wise into the solution for 2 hrs. The mixture was then placed into an oven at 100 oC for 24 hrs. They were further calcined at 800 oC for 3 hrs. XRD, FTIR and ICP-MS were used to identify the structure and composition. It was found that the final powders were predominantly monetite, with some tricalcium phosphate as a secondary phase. This relatively simple and efficient method can be easily applied to produce calcium phosphate precursor powders for a range of biomedical applications.
Antibiotic Containing Poly Lactic Acid/Hydroxyapatite Biocomposite Coatings for Dental Implant Applications
(Trans Tech Publications Inc, 2017-11) Karacan, Ipek; Macha, Innocent J; Choi, Gina; Cazalbou, Sophie; Ben-Nissan, Besim
The biodegradable and biocompatible antibiotic containing thin film composites are very appropriate biomaterials as coating materials for dental implants because of their adjustable drug loading and release rates for the prevention of implant related infections. Coralline hydroxyapatite (HAp) was loaded with gentamicin antibiotics and combined with a biodegradable polylactic acid (PLA) to form thin film composites. PLA-HAp, PLA-Gentamicin (GM) and PLA-HAp-GM composites were produced, and their dissolution studies were carried out in phosphate buffered saline under SINK conditions. It was observed that the coatings could be efficiently applied to titanium dental implants and the drug release rates can be efficiently controlled.
Biocompatibility of a new biodegradable polymer-hydroxyapatite composite for biomedical applications
(Elservier, 2017-04) Macha, Innocent J; Ben-Nissan, Besim; Santos, Jerran; Cazalbou, Sophie; Stamboulis, Artemis; Grossin, David; Giordano, Gerard
The rise in the number of musculoskeletal disorders (MSDs) due to an increasingly aging population has led to a growing demand for medication to prevent and treat these diseases. An increased interest in the development of new drugs to allow treatment of these diseases in their very early stages is currently observed. The current approach on local direct delivery of medication and key minerals to support bone repair and regeneration at the defect site, from flexible degradable devices, seems to be an effective strategy. Polylactic acid (PLA) and microspheres of hydrothermally converted coralline hydroxyapatite (cHAp) were used to develop PLA thin film composites as drug delivery systems. The PLA provided flexibility and biodegradability of the systems, while coralline hydroxyapatite provided the required calcium and phosphate ions for bone regeneration. These coralline hydroxyapatite microspheres have a unique architecture of interconnected porosity, are bioactive in nature and suitable for drug loading and controlled slow drug release. The cell attachment and morphology of the PLA thin film composites were evaluated in vitro using cell cultures of human adipose derived stem cells (hADSC). It was shown that hADSC cells exhibited a strong attachment and proliferation on PLA thin film-cHAp composites, signifying high biocompatibility and a potential for osteointegration due to the presence of HAp.
Calcium phosphate and bioglass reinforced PLA thin film biocomposites for slow drug delivery applications
(2016-03) Macha, Innocent J
The rise in the number of musculoskeletal disorders (MSDs) due to the increase in aging population and advancement in medical technology has led to an increasing demand for medication to prevent and treat these diseases. The development of new drugs or formulations to allow treatment of these diseases in their very early stages is only increasing. Local direct and multidelivery of medication and key minerals to support bone repair and regeneration at the defect site, from flexible degradable devices at the rate within the therapeutic window, seems to be an effective strategy. However current drug delivery vehicles are neither flexible and degradable, nor able to deliver both medication and minerals effectively. Using a simple “solution casting” method, preparation of medical devices with such potential for slow drug delivery for biomedical applications served as the research objective. Polylactic acid (PLA) and hydroxyapatite-hydrothermally converted coral were used to develop PLA thin film composites as drug delivery systems. PLA provided flexibility and biodegradability of the systems, while coralline hydroxyapatite provided a unique architecture with its porous and bioactive nature, which is suitable for drug loading and slow drug release. Two drugs, gentamicin (antibiotic) and bisphosphonate were loaded into the device and their release profiles and activities were studied for the treatment of medical-implant related infection and osteoposis respectively. The biocompatibility study on human adipose derived stem cells (hADSC) and biofilm formation behaviour of both gram-negative (Pseudomonas aeruginosa) and gram-positive bacterial (Staphylococcus aureus) were studied on PLA thin film composites loaded with gentamicin. The mechanical properties of PLA-surface treated bioglass for tissue engineering applications was also studied. An alternative conversion method of coralline materials and other natural materials such as sea mussel and ostrich eggshells to calcium phosphate materials were also evaluated. Although nanosurface bioglass treated with 1% (3-Aminopropyl) triethoxysilane (APTES) suggested effective improvement in elongation at the break of PLA/bioglass composites, they lacked the required drug release efficiency. However, the PLA thin film composites displayed ability for potential applications in biomedical field as drug delivery systems. The flexibility they provide allows them to conform to any desired clinical shape and size. Incorporation of hydroxyapatite in the matrix, has the added advantages of controlled release, improved encapsulation efficiency, increased drug stability and maintenance of bioactivity and continuous supply of calcium Ca²⁺ and phosphate PO₄²⁻ ions, which can assist in bone regeneration and repair. Gentamicin release profiles, exhibited a steady state release rate, with significant antimicrobial activity even at high concentrations of bacteria. The systems also showed the potential for prolonged release of both antibiotic and bisphosphonate. The loading of the drug onto HAp particles induces a significant decrease of the release rate and period, for both gentamicin and bisphosphonate permitting the therapeutic efficacy of composite biomaterial locally to be extended. hADSC showed attachment and proliferation on PLA thin film-HAp composites signifying the increase in osteointegration due to the presence of HAp. Mechano-chemical conversion methods proved to be an effective alternative to the hydrothermal technique for coral conversion to calcium phosphate materials at moderate temperature conditions. The modified composites may have a wide range of biomedical applications in tissue engineering with improved elastic properties.
Comparative Study of Conversion of Coral with Ammonium Dihydrogen Phosphate and Orthophosphoric Acid to Produce Calcium Phosphates
(Springer NATURE, 2014-01) Cegla, Rabea-Naemi Rosa; Macha, Innocent J; Ben-Nissan, Besim; Grossin, David; Heness, Greg; Ren-Jei, Chung
Biogenic materials like corals, which are readily available, could be used to produce bioceramic materials and address significant advantages due to their unique structures and chemical compositions that contain Mg and Sr. Many conversion processes has been in the past proposed. In this work, a comparison study between the conversion of coral with orthophosphoric acid and ammonium dihydrogen phosphate was conducted. The resultant structures and compositions were studied using XRD, ICP-MS, SEM and FTIR. The results show that with phosphoric acid the coral was converted into mainly monetite (92%). The ammonium dihydrogen phosphate converted approximately 76% of the coral to hydroxyapatite through solid state reactions. The two routes proved to be effective in producing bioceramic materials from corals under moderate conditions of temperature with a basic condition favouring the yield of hydroxyapatite.
Comparative Study of Conversion of Coral with Ammonium Dihydrogen Phosphate and Orthophosphoric Acid to Produce Calcium Phosphates
(Springer NATURE, 2014) Cegla, Rabea-Naemi Rosa; Macha, Innocent J; Ben-Nissan, Besim; Grossin, David; Heness, Greg; Chung, Ren-Jei
Biogenic materials like corals, which are readily available, could be used to produce bioceramic materials and address significant advantages due to their unique structures and chemical compositions that contain Mg and Sr. Many conversion processes has been in the past proposed. In this work, a comparison study between the conversion of coral with orthophosphoric acid and ammonium dihydrogen phosphate was conducted. The resultant structures and compositions were studied using XRD, ICP-MS, SEM and FTIR. The results show that with phosphoric acid the coral was converted into mainly monetite (92%). The ammonium dihydrogen phosphate converted approximately 76% of the coral to hydroxyapatite through solid state reactions. The two routes proved to be effective in producing bioceramic materials from corals under moderate conditions of temperature with a basic condition favouring the yield of hydroxyapatite.
Comparative study of Coral Conversion, Part 2: Microstructural evolution of calcium phosphate
(Springer NATURE, 2015-06) Macha, Innocent J; Boonyang, Upsorn; Cazalbou, Sophie; Ben-Nissan, Besim; Charvillat, Cédric; Oktar, Faik N; Grossin, David
Calcium phosphate materials can be easily produced by a number of wet chemical methods that involve both acidic and basic environments. In our previous study, we investigated calcium phosphates such as monetite (DCPA), hydroxyapatite (HAp) and whitlockite which were successfully produced by mechano-chemical method from corals obtained from the Great Barrier Reef. It was observed that a number of synthesis factors such as the pH of the environment, the reaction temperature and the chemistry influenced the crystal size formed. A number of theories have been suggested on the mechanisms of crystal formation; however, very few mechanisms have been universally accepted. The present work was aimed to explore the evolution of crystalline calcium phosphate and their morphology with respect to the pH of the environment and reaction time. Conversion of coral to calcium phosphates was carried out with stoichiometric amount of required H3PO4 or (NH4)2HPO4, to obtain hydroxyapatite or tricalcium phosphate (TCP) phases. The acidic or basic solution was added, drop wise, at a rate of 2 mL min-1, to 6 g of coral powder suspended in 300 mL of distilled water at 80 ± 0.5°C on a hot plate with magnetic stirrer. The pH of reaction was monitored. Crystal morphology and the phases were identified by XRD, FTIR, and SEM studies. It was observed that under acidic conditions (H3PO4), dissolution and then precipitation influences the crystal morphology and transition from plate like to rod like hydroxyapatite structure. During the first hour of the dissolution a monetite and hydroxyapatite mixture precipitates and then the full conversion to hydroxyapatite is observed. However under basic conditions (NH4)2HPO4), pH is only marginally changed within the environment and just surface conversion of the calcium carbonate structure of coral to hydroxyapatite and a very small amount of tri-calcium phosphate is observed. The mechanism can be classified as the solid state topotactic ion-exchange reaction mechanism.
Comparative Study of Coral Conversion, Part 3: Intermediate Products in the First Half an Hour
(2015-12) Macha, Innocent J; Charvillat, Cédric; Cazalbou, Sophie; Grossin, David; Boonyang, Upsorn; Ben-Nissan, Besim
Understanding what really happen during reaction will pave a way to tune the final product for well-defined morphology and purity. We focused into improving in-depth understanding of the reaction mechanisms and the intermediates products participating in the reaction of coralline materials with orthophosphoric and ammonium phosphate solutions under mechano-chemical reaction technique. The results suggest that within 30 minutes of reaction under ammonium phosphate solution only HAp phase is produced through solid-state iron exchange reaction. On the other hand, under orthophosphoric acid solution, intermediate phases such as octacalcium phosphate (OCP) and monetite form and convert to hydroxyapatite HAp at different times. Other phase that formed as an intermediate was identified as brushite. It was also observed that pH plays a big role in the formation of these phases due to their different pH stability. The results also confirm our previous hypothesis that under orthophosphoric acid phosphate solution the reaction mechanism is dissolution-recrystallization while under ammonium phosphate solution is solid-state topotactic ion exchange reaction mechanism. It is envisaged that there are possibilities of the formation of intermediate products within or before the fir
Conversion of Marine Structures to Calcium Phosphate Materials: Mechanisms of Conversion using two Different Phosphate Solutions
(2016-03) Macha, Innocent J; Grossin, David; Ben-Nissan, Besim
Marine structure, coralline materials were converted to calcium phosphate using two different phosphate solutions. The aim was to study the conversion mechanisms under acidic and basic environment at moderate conditions of temperature. Crystal growth and morphology of converted corals were characterized by XRD and SEM respectively. The results suggested that under acidic conditions (H₃PO₄), dissolution and precipitation control and direct the crystal formation and morphology in which transition from plate like to rod like hydroxyapatite structure was favoured. Metastable phase such as monetite formed and transformed to HAp during reaction. During the first hour of the dissolution a monetite and hydroxyapatite mixture precipitates and then the full conversion to hydroxyapatite is observed. On the other hand, under basic conditions (NH₄)2HPO₄, just diffusional surface conversion of the calcium carbonate structure of coralline materials to hydroxyapatite and a very small amount of tri-calcium phosphate is observed. The mechanism can be classified as the solid-state topotactic ion-exchange reaction mechanism.
Conversion of Ostrich Eggshells (Struthio camelus) to Calcium Phosphates
(2015-01) Macha, Innocent J; Ozyegin, L S; Faik, Oktar N; Ben-Nissan, Besim
The exceptional progress made in orthopaedic and dental applications have increased the demand of calcium phosphate bioceramics due to their chemical similarities to the inorganic component of hard tissues. Low cost production of calcium phosphate bioceramics could be achieved by using pure natural biogenic materials by relatively simple methods. In this study calcium phosphate powders were produced from ostrich (Struthio camelus) eggshell powder at a moderate temperature of 80oC by relatively simple process of low temperature heating by hot plate (HP) and hot platting while agitation with ultrasonication (HPUS) hence introducing mechanical activation. The product structure and compositions were studied with FTIR, SEM, DTA/TCA, XRD and ICP techniques. The results showed that calcium deficient hydroxyapatite and dicalcium phosphate were obtained from HP and HPUS methods. Poorly crystalline calcium deficient hydroxyapatite was converted into whilockite after calcining at 800oC. The results suggest that this low cost and relatively simple method is efficient to easily produce calcium phosphate powders from adequately feed controlled farms to obtain pure uncontaminated eggshells for a range of biomedical applications.
Development and dissolution studies of bisphosphonate (clodronate)-containing hydroxyapatite–polylactic acid biocomposites for slow drug delivery
(2015-07-15) Macha, Innocent J; Cazalbou, Sophie; Shimmon, Ronald; Ben-Nissan, Besim; Milthorpe, Bruce
An increase in clinical demand on the controlled release of bisphosphonates (BPs) due to complications associated with systemic administration, has been the current driving force on the development of BP drug-release systems. Bisphosphonates have the ability to bind to divalent metal ions, such as Ca2+, in bone mineral and prevent bone resorption by influencing the apoptosis of osteoclasts. Localized delivery using biodegradable materials, such as polylactic acid (PLA) and hydroxyapatite (HAp), which are ideal in this approach, have been used in this study to investigate the dissolution of clodronate (non-nitrogen-containing bisphosphonate) in a new release system. The effects of coral structure-derived HAp and the release kinetics of the composites were evaluated. The release kinetics of clodronate from PLA–BP and PLA–HAp–BP systems seemed to follow the power law model described by Korsmeyer–Peppas. Drug release was quantified by 31P-NMR with detection and quantification limits of 9.2 and 30.7 mM, respectively. The results suggest that these biocomposite systems could be tuned to release clodronate for both relatively short and prolonged period of time. In addition to drug delivery, the degradation of HAp supplies both Ca2+ and phosphate ions that can help in bone mineralization.
Development and In Vitro Analysis of a New Biodegradable PLA/Hydroxyapatite (HAp) Composite for Biomedical Applications
(2017-06-08) Macha, Innocent J; Ben-Nissan, Besim; Choi, Andy H.; Cazalbou, Sophie
The development of new drugs or formulations for the treatments of different musculoskeletal disorders (MSDs) has now being a focus of pharmaceutical and scientific societies. Targeted and multidelivery of drug and key minerals to support bone repair and regeneration at the defect site, from flexible biodegradable devices at the rate within the therapeutic window, seem to be an effective strategy. However, the drug delivery vehicles available are neither flexible and degradable nor able to deliver both pharmaceutical drug and minerals effectively. The use of biodegradable polymer and bioceramic for composite development with enough flexibility and potential for slow in situ drug delivery for biomedical applications could be one of the real options to mitigate MSDs problem. In vitro analysis of the developed devices is a vital step towards clinical trial and commercialization of the implant. Different approach and results have been compared to draw guidelines for the development and testing of thin film composite applications as a slow drug delivery vehicle.
Development of antimicrobial composite coatings for drug release in dental, orthopaedic and neural prostheses applications
(Springer NATURE, 2019-01) Macha, Innocent J; Karacan, Ipek; Ben-Nissan, Besim; Cazalbou, Sophie; Muller, Wolfgang H
While one of the major clinical and scientific challenges in the management of implant-related infections and post- operative complications after surgery is the application of new techniques, a new approach is pertinent in the design of medical implants to reduce bacterial infections. We have designed and tested antibiotic-containing biocomposite thin films of polylactic acid (PLA), and coralline-derived hydroxyapatite (HAp) as controlled drug delivery systems for the treatment of dental, orthopaedic and neural implant-related post-operative infections. These films can be applied to complicated designs of dental, miniaturized neural devices, cochlear or total hip replacement (THR) implants by spray or dip-coating techniques. Current results reveal that the devices could release antibiotic in a controlled manner to prevent significantly bacterial growth and biofilm production. Hydroxyapatite within the composites controls the release rate and also supplies minerals, such as calcium Ca2+ and phosphate PO42− ions, which are essential minerals for bone tissue regeneration. It is concluded from the physical, mechanical and biological properties that these coatings and devices could easily be utilized in a wide range of biomedical applications.
Effects of phase additions on three dimensionally ordered macroporous structure of SiO2-CaO-P2O5 bioactive glasses
(2016-02) Charoensuk, Thanida; Sirisathitkul, Chitnarong; Boonyang, Upsorn; Macha, Innocent J; Sirisathitkul, Yaowarat; Ben-Nissan, Besim
The three-phase of SiO2-CaO-P2O5 bioactive glass was successfully fabricated with three dimensionally ordered macroporous (3DOM) structure by incorporating a colloidal crystal template in the sol-gel synthesis. Whereas the composition and purification of all four- and five-phase bioactive glasses were obtained after the inclusion of sodium nitrate and ferric nitrate nonahydrate, the phase additions resulted in the deformation of the scaffolds and the curved walls were thinner with larger variations in size. Such difference was due to the gel-coating on spherical crystals instead of the filling in the interstitial holes of the template. Moreover, the bioactive glass microspheres were formed on the surface of the scaffolds due to the strong precursor-template interactions. Nevertheless, the five-phase bioactive glasses exhibited the thermal stability up to 1000 oC with slight mass loss and heat transfer.
Hydroxyapatite/PLA Biocomposite thin Films for Slow Drug Delivery of Antibiotics for the Treatment of Bone And Implant-Related Infections
(2016-03) Macha, Innocent J; Ben-Nissan, Besim; Santos, Jerran; Cazalbou, Sophie; Milthorpe, Bruce K.
rug delivery systems were developed from coralline hydroxyapatite (HAp) and biodegradable polylactic acid (PLA). Gentamicin (GM) was loaded in either directly to PLA (PLAGM) or in HAp microspheres. Drug loaded HAp was used to make thin film composites (PLAHApGM). Dissolution studies were carried out in phosphate buffered saline (PBS. The release profiles suggested that HAp particles improved drug stabilization and availability as well control the release rate. The release also displays a steady state release. In vitro studies in human Adipose Derived Stem Cells (hADSCs) showed substantial quantities of cells adhering to hydroxyapatite containing composites. The results suggested that the systems could be tailored to release different clinical active substances for a wide range of biomedical applications.
Improvement of Elongation in Nanosurface Modified Bioglass/PLA Thin Film Composites
(Bentham Science, 2014-01) Macha, Innocent J; Ben-Nissan, Besim; Milthorpe, Bruce
One of the major challenges in the development of biomaterials is the adaptation of the complex elastic nature and elongation of human tissues during biomechanical functional loading. Composite materials present the most appropriate means of attempting to match the mechanical and biocompatibility requirements. Composite films from polylactic acid (PLA) and sol-gel derived bioglass (BG) powders with particle size ranging from 50-100 nm were produced by solution casting method. Three different bioglass mixtures of 0.1, 0.5 and 1% bioglass were prepared. Physico-chemical and morphological properties of bioglass, pure PLA and PLA composites were investigated using XRD, SEM and FTIR. Bioglass particles were further treated by nanolayer coating of 3-aminopropyltriethoxysilane (APTES) to improve its mechanical properties. The effects of surface treated bioglass on the fracture of the PLA/bioglass composites were investigated under tensile loading conditions. The results suggest by nano-surface treating the bioglass with 1% APTES significantly influences the percentage elongation of the PLA/bioglass composite at fracture. SEM shows more agglomeration of untreated bioglass within the composite. In the treated samples, a better distribution of nanosized bioglass within PLA matrix was observed. Nanolayer modified bioglass /PLA thin film composites may have a wide range of biomedical applications in tissue engineering with improved elastic properties.
IN VITRO ANALYSIS OF ANTIMICROBIAL PROPERTIES OF HONEY AND TUMERIC ON COTTON WOVEN FABRIC FOR WOUND DRESSING APPLICATION
(2018-08) Maguru, Beatus; Macha, Innocent J
An attempt has been made to develop anti-microbial textiles by studying the Inhibition zone using honey and turmeric. The concentration of honey and turmeric was as 10:0, 7:3, 5:5, 3:7, and 0:10 and it was applied on to the fabric using direct padding method. The antimicrobial activity of honey and turmeric treated fabric were tested against the infectious bacteria Staphylococcus aureus. Both the samples show better results against the bacteria but honey shows the best results by largest Inhibition Zone diameter.

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