An　appropriate　surface　chemical　property　is　crucial　in　tissue　engineering　scaffolds,　which　promotes　cell　attachment　and　proliferation.　A　biomimetic　composite　scaffold　with　a　polydopamine　(PDA)　coating　layer　on　electrospun　poly(lactic　acid)　(PLA)/cellulose　nanofibrils　(CNF)　composite　nanofiber　was　developed　in　this　study.　PLA/CNF　composite　nanofibers　were　fabricated　and　then　coated　via　treatment　with　a　dopamine　solution.　The　PDA　coating　layer　was　successfully　formed　on　the　surface　of　the　PLA/CNF　composite　nanofiber　by　using　a　simple,　environment-friendly,　and　effective　procedure.　Results　indicated　that　the　addition　of　CNF　into　the　PLA　matrix　can　effectively　improve　the　deposition　rate　of　the　PDA　coating　layer　on　the　surface　of　the　composite　nanofiber　during　the　initial　stage　of　coating　because　of　hydrogen　bonding　between　the　CNF　and　PDA　molecular　chains.　The　hydrophilicity　and　mechanical　properties　of　the　PLA/CNFPDA　scaffold　were　higher　than　those　of　the　PLA/CNF　scaffold.　In　addition,　the　cell　culture　test　showed　that　the　adhesion,　proliferation,　and　growth　of　human　mesenchymal　stem　cells　(hMSCs)　cultured　on　the　PLA/CNFPDA　scaffold　were　significantly　enhanced　relative　to　those　cultured　on　the　PLA/CNF　scaffold　because　of　the　introduction　of　the　PDA　coating.　This　finding　suggested　that　surface　biofunctionalization　via　the　PDA　coating　layer　could　simply　and　effectively　enhance　cell　biocompatibility　for　polymer-based　scaffolds.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.