title: Surfactant free rapid synthesis of hydroxyapatite nanorods by a microwave irradiation method for the treatment of bone infection.
abstract: Mesoporous nanocrystalline hydroxyapatite (nHAp) rods of size 40-75 nm long and 25 nm wide (resembling bone mineral) were synthesized under microwave irradiation without using any surfactants or modifiers. The surface area and average pore size of the nHAp were found to be 32 m(2) g(-1) and 4 nm, respectively. Rifampicin (RIF) and ciprofloxacin (CPF) loaded nHAp displayed an initial burst followed by controlled release (zero order kinetics). Combination of CPF and RIF loaded nHAp showed enhanced bacterial growth inhibition against Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli) compared to individual agent loaded nHAp and pure nHAp. In addition, decreased bacterial adhesion (90%) was observed on the surface of CPF plus RIF loaded nHAp. The biocompatibility test toward MG63 cells infected with micro-organisms showed better cell viability and alkaline phosphatase activity (ALP) for the combination of CPF and RIF loaded nHAp. The influence on cell viability of infected MG63 cells was attributed to the simultaneous and controlled release of CPF and RIF from nHAp, which prevented the emergence of subpopulations that were resistant to each other. Hence, apart from the issue of the rapid synthesis of nHAp without surfactants or modifiers, the simultaneous and controlled release of dual drugs from nHAp would be a simple, non-toxic and cost-effective method to treat bone infections.
authors.affiliation: Crystal Growth Centre, Anna University, Chennai 600 025, India.
authors.forename: R
authors.initials: R
authors.lastname: Vani
authors.forename: Subramaniya Bharathi
authors.initials: SB
authors.lastname: Raja
authors.forename: T S
authors.initials: TS
authors.lastname: Sridevi
authors.forename: K
authors.initials: K
authors.lastname: Savithri
authors.forename: S Niranjali
authors.initials: SN
authors.lastname: Devaraj
authors.forename: E K
authors.initials: EK
authors.lastname: Girija
authors.forename: A
authors.initials: A
authors.lastname: Thamizhavel
authors.forename: S Narayana
authors.initials: SN
authors.lastname: Kalkura
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D001422:Bacterial Adhesion / Q000187:drug effects; D001847:Bone Diseases / Q000188:drug therapy*; D001842:Bone and Bones / Q000187:drug effects / Q000382:microbiology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002939:Ciprofloxacin / Q000494:pharmacology / Q000627:therapeutic use; D017886:Durapatite / Q000138:chemical synthesis*; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D008872:Microwaves; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D012293:Rifampin / Q000494:pharmacology / Q000627:therapeutic use; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013499:Surface Properties / Q000187:drug effects; D013501:Surface-Active Agents / Q000494:pharmacology*; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D013501:Surface-Active Agents; D002939:Ciprofloxacin; D017886:Durapatite; D000469:Alkaline Phosphatase; D012293:Rifampin