Oral Presentations - Pathology and Laboratory Medicine - University ...

Post-doctoral FellowAbstract # 51Guangzheng Gao, Jason Kindrachuk, Donald E. Brooks, Robert E.W. Hancock,and Jayachandran N. KizhakkedathuCentre for Blood Research, Department of Pathology and Laboratory MedicineGao Guangzhengshort antimicrobial peptides immobilized copolymerbrushes on titanium surfaceBackround/ObjectivesImplant-associated infection is one of the most challenging postoperative complications, especially in the case oforthopedic implants. Thus the design of novel anti-infective implant surfaces would be highly advantageous withsignificant benefit to both patients and the health care system. A potential alternative to current antibiotics isantimicrobial peptides (AMPs) that are found in the immune system of almost all species of life.In the present work, we investigated the immobilization of small AMPs on titanium surfaces using novel functionalcopolymer brushes.We show that the properties of the copolymer brushes significantly affect the peptide density onthe brushes and their antimicrobial activity.MethodsWe synthesized of primary amine functionalized copolymer brushes on Ti surface using surface initiated atomtransfer radical polymerization (SI-ATRP) technique and developed methods for the efficient conjugation of cysteinecontaining AMPs on copolymers brushes and their characterization. Antibacterial analyses were conducted byincubating Tet-213 immobilized Ti plates and corresponding control samples in a 24-well microtiter plate with luxstrain culture. Luminescence emission was examined by a TECAN® Spectrafluor Plus spectrometer (TECAN U.S.,Inc.).ResultsN-(3-Aminopropyl)methacrylamide hydrochloride (APMA) and N, N-Dimethyl acrylamide (DMA) copolymerbrushes were synthesized on Ti surface by surface initiated ATRP in aqueous conditions at room temperature.Cysteine-containing AMP Tet-213 was conjugated to the copolymer brushes after modification of amine groupsto maleimide groups. The antimicrobial properties of the selected peptide-coated samples were analyzed usingPseudomonas aeruginosa (P. aeruginosa) strain PA01 that expresses a luciferase gene. Our preliminary data show thatthe polymer brushes grafted Tet-213 retains antimicrobial activity. Bacterial growth inhibition could reach 80%.ConclusionWe showed that the primary amine groups within the brushes were highly reactive to small molecules, and almostquantitative conversion of amine groups to maleimide groups was obtained. The peptide conjugation of copolymerbrushes depended on molecular weight, graft density and composition. The graft density of the chains on the brushesshowed significant influence on the peptide conjugation unlike other parameters. Many folds higher peptide density onthe surface was achieved when the brush layer was used for conjugation. As a proof-of-concept, we showed that peptideconjugated copolymer brushes were antimicrobial.62 2 0 1 0 * P o s t e r P r e s e n t a t i o n s