1. Introduction Titanium (Ti) and Ti alloys have been extensively used in dental and orthopaedic areas as implants due to their biocompatibility, low density and good me- chanical properties. However, unmodified Ti may host bacterial infections after implantation [1]. These in- fections often lead to implant failure, removal of im- plants, higher treatment costs, and also increased pa- tient morbidity or in some cases perioperative mor- tality. Infections must be treated carefully with antimi- crobial agents. High systemic doses of some agents may cause various side effects including nephrotox- icity and ototoxicity. Applications of local antimi- crobial agents have generated much interest as an al- ternative drug delivery system. Basically, local drug delivery will allow for a better control of drug appli- cation directly at the required site/location for an ex- tended period of time. Various antibiotic coatings on Ti have been investi- gated to provide a local antibacterial delivery to a Ti implant [2]. Most studies have involved incorporat- ing antibiotics into numerous types of materials coat- ings such as carbonated hydroxyapatite [3] chitosan (Chi) [4] and tetraethylorthosilane [5] either directly, as a film or a layer-by-layer (LBL) coating [6–8]. Modifications of titanium implant surfaces by cova- 73 Layer-by-layer gelatin/chitosan polyelectrolyte coated nanoparticles on Ti implants for prevention of implant-associated infections T. Sangfai 1 , F. Dong 2 , V. Tantishaiyakul 1,3* , K. D. Jandt 2 , C. Lüdecke 2 , O. Boonrat 1, N. Hirun 4 1 Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, 90112 Hat-Yai, Thailand 2 Otto Schott Institute of Materials Research, Friedrich-Schiller-University Jena, Löbdergraben 32, 07743 Jena, Germany 3 Nanotec-PSU Center of Excellence for Drug Delivery System, Faculty of Pharmaceutical Sciences, Prince of Songkla University, 90112 Hat-Yai, Thailand 4 Theoretical and Computational Modeling Research Group and School of Pharmacy, Walailak University 80161, Nakhon Si Thammarat, Thailand Received 1 July 2016; accepted in revised form 14 September 2016 Abstract. Gelatin nanoparticles (Gb-NP) and layer-by-layer (LBL) coated NPs were developed to modify a Ti substrate surface to prevent implant-associated infections. Vancomycin (Van) was loaded into these materials to obtain GbV-NP and LBL-GbV-NP. The size of the GbV-NP (277.4±1.4 nm) was smaller than that of LBL-GbV-NP (710.2±4.6 nm) but both had a spherical shape. These coated materials showed no cytotoxicity and facilitated better cell proliferation by osteoblast-like cells compared to the bare Ti. This was probably due to the roughness of the coated NP that enhanced cell attachement to the surface. Both coated materials showed antibacterial activity against S. aureus. The release of Van from GbV-NP was higher from LBL-GbV-NP and this corresponded to their antibacterial activity. Furthermore the release profile of Van showed a sustained release. Thus both materials should be able to prolong the protection of implant-associated infections to the bone. Keywords: nanomaterials, coatings, biocompatible polymers, vancomycin, Ti implantation eXPRESS Polymer Letters Vol.11, No.1 (2017) 73–82 Available online at www.expresspolymlett.com https://doi.org/10.3144/expresspolymlett.2017.8 * Corresponding author, e-mail: vimon.t@psu.ac.th © BME-PT