Antimicrobial PLA and Calcium Phosphate Coatings and Thin Film Composites for Implants Applications

University of Technology Sydney. Faculty of Science.Implant-related infections after the insertion of biomedical implants are still prevalent, and the current treatment methodology requires the use of large doses of antibiotics systemically. Large doses can lead to a number of side effects including antibiotic resistance and adverse effects on the other organs. These infections delay healing, worsen functional outcome and incur significant socioeconomic costs. Bone implant related infections, surgery site infections (SSI), and osteomyelitis remain the most challenging clinical problems faced. This thesis aimed to develop a novel implant coating system based on a ‘Local and Controlled Antibiotic Delivery System with Biodegradable Polymeric Thin Film Composite Coating’ for metallic bone implants. The specific aim of this study was to design a novel multi-functional and antibacterial coating for implants as the drug delivery systems to prevent post-operative complications and osteomyelitis. The main challenge was to obtain the perfect design and the selection of appropriate biomaterials; implantable device with antibacterial, biocompatible and bioactive properties. Therefore, gentamicin antibiotic (Gm) and Gm loaded coralline hydroxyapatite (HAp) particles were incorporated into a poly-lactic acid (PLA) matrix as the main biocomposite. A number of systems were produced, characterized and tested, which included PLA, PLA-Gm mixture, and a PLA-Gm-(HAp-Gm) biocomposite. The coral skeleton (CaCO₃) was converted to HAp by using the hydrothermal conversion method. These microspheres were loaded with Gm and HAp-Gm particles and incorporated within the PLA thin film composites. Coralline-HAp possesses a unique nano- and meso-porous structure and can be used as a drug carrier for the sustained release of antibiotics on metallic bone implants. While the physiochemical characterizations of the PLA biocomposite coating were evaluated, their Gm release profile were analyzed by the continuous dissolution method. The bioactivity and biocompatibility of the design was tested on Adipose-derived stem cells using studies. The antibacterial activity and biofilm formation behaviour were also analyzed with . and . . Different Gm concentrations (5%, 10%, 15%, 20% and 30% [w/w]) were incorporated into the PLA biocomposites and were found to be highly effective on the inhibition of . and . growth at the planktonic stage. At the biofilm formation stage of . , the significant reduction of bacterial attachment and the increasing of dead microcolonies were observed for even the lowest 5% (w/w) PLA-Gm-(HAp-Gm) coated samples. This research showed that the biodegradable and antibacterial PLA biocomposite coatings design has high potential as a viable alternative method for existing clinical applications on many metallic orthopedic and maxillofacial bone implants

Antibiotic Containing Poly Lactic Acid/Hydroxyapatite Biocomposite Coatings for Dental Implant Applications

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

Conversion of Calcified Algae (Halimeda sp) and Hard Coral (Porites sp) to Hydroxyapatite

Calcium phosphate materials can be produced using a number of wet methods that are based on hydrothermal or co-precipitation methods that might use acidic or basic chemical environments. In our previously published works, we have investigated calcium phosphates such as monetite, hydroxyapatite, and whitlockite which were successfully produced by mechano-chemical methods and/or hydrothermal treatments from a range of marine shells and corals which were obtained from the Great Barrier Reef. The aim of the current work was to analyze and compare the mechanisms of conversion of one hard coral species and one calcified algae species from the Great Barrier Reef

Current management of acute bronchiolitis in Turkey [Türkiye'deki pediatristlerin akut bronşiyolite güncel yaklaşimlari]

Acute bronchiolitis is the most common lower respiratory tract infection in infants. The aim of this study was to overview the treatment practices of pediatricians in Turkey and to compare them with the current international management approaches. Questionnaires about acute bronchiolitis were distributed to pediatricians in the 49 th National Congress of Pediatrics and 2nd Congress of Pediatric Emergency and Intensive Care. The questionnare described a clinical scenario and this was followed by a list of management questions. Of a total of 300 questionnaires, 160 (53%) were returned. Of the participants, 88% give inhaled salbutamol, and 74% only oxygen or inhaled salbutamol plus oxygen in children with moderate acute bronhiolitis. Pediatricians in state hospitals use steroid (42%) and cold mist therapy (10%) more than in university and training hospitals (p<0.05). Epinephrine administration was significantly lower than in state hospitals and university and training hospitals, respectively at 2% and 5%. The most common survey in acute bronchiolitis was chest radiographs (68%). Antibiotics were prescribed routinely by 10% of state hospital pediatricians and by 6% of university and training hospital pediatricians. In conclusion, in light of the new, randomized, controlled clinical research and meta-analyses, guidelines have to be updated and continuous education provided with evidence-based protocols