Ren Hu

Role of trapped air in the formation of cell-and-protein micropatterns on superhydrophobic/superhydrophilic microtemplated surfaces

Air trapped within the interstices of TiO(2) nanotube surfaces bearing superhydrophobic/superhydrophilic microtemplated domains controls formation of protein micropatterns but not cell micropatterns. Protein binding from either bovine-serum albumin (BSA) or fetal-bovine serum (FBS) solutions to superhydrophobic domains is blocked in the presence of trapped air, leading to clear protein binding contrast between superhydrophilic and superhydrophobic domains. Protein binds to superhydrophobic domains when air is displaced by sonication, leading to more protein binding to superhydrophobic domains than to superhydrophilic, with concomitantly blurred protein binding contrast. The overall contrast obtained in formation of cell (hFOB1.19, MG63, and HeLa) micropatterns depends on the cell type and protein composition of the fluid phase. All cell types preferentially attach to superhydrophilic domains from each fluid phase tested (FBS, BSA, and basal media containing no protein). All cell types do not attach to superhydrophobic domains from FBS solutions, with-or-without trapped air, creating a visually-obvious cell attachment pattern. However, cells attached to superhydrophobic domains from basal media suspensions, with-or-without trapped air, creating a blurred cell attachment pattern. Cell attachment from BSA-containing solutions gave mixed results depending on cell type. Thus, trapped air does not necessarily block cell attachment as has been suggested in the literature. Rather, cell attachment is controlled by interfacial tensions between cells, surfaces, and fluid phases in a manner that can be understood in terms of the Dupré work-of-adhesion formulation. Cell attachment patterns developed within the initial attachment phase persist for up to two days of continuous culture but overgrow thereafter, with-or-without trapped air, showing that trapped air does not block cell overgrowth over time of continuous culture.

A novel nano‐micro structured octacalcium phosphate/protein composite coating on titanium by using an electrochemically induced deposition

In this study, a novel nano-micro structured octacalcium phosphate/protein (OCP/protein) composite coating has been successfully constructed on titanium substrate by using an electrochemically induced deposition technique. The structure and composition of the composite coating were investigated by XRD, XPS, SEM and FTIR. It is shown that the composite coating consists of OCP and protein with a highly ordered and hierarchically porous structure in nano-micro scale, similar to the naturalbone structure. The nanoindentation experiment proves a good mechanical property for the OCP/protein composite coating on titanium substrate. In the osteoblast cell culture in vitro, the cell adhesion for the OCP/protein composite coating is observed to be greatly improved.

Antibacterial and cytocompatible AgNPs constructed with the assistance of Mefp-1 for orthopaedic implants

The increasing threat of orthopedic implant failure caused by infection and loosening intensifies the need for novel surface functional treatment. In this study, a thin mussel adhesive protein (Mefp-1)/silver nanoparticle (AgNP) composite film constructed on titania nanotubes (TNTs) via a simple dip-coating method has been demonstrated. The TNT/Mefp-1/AgNP coating exhibits both high antibacterial activity and adequate cytocompatibility. The adherent Mefp-1 film could promote preosteoblast proliferation and reduce AgNP-induced cytotoxicity. The AgNPs (∼10 nm) constructed with the assistance of Mefp-1 are effective for the elimination of both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) via a combination of contact-killing and release-killing modes. This facile and mild functionalization strategy exhibits promising applications in surface antibacterial modifications, especially in three-dimensional sophisticated medical devices.

Electrochemically-Induced Deposition of Protein and Calcium Phosphate Coating on Titanium

A nano-micro structured protein/octacalcium phosphate composite coating was prepared by electrochemically-induced deposition (ED) onto titanium surface. The characterizations of XRD, SEM and FT-IR indicate that the as prepared composite coating consists of protein and octacalcium phosphate with a highly and hierarchically porous structure in nano-micro scale, similaring to the natural bone structure.

Electrochemical preparation of ordered nano HAp coatings on Ti substrate and in vitro study on its bioactivity

The HAp coatings with various surface morphologies were electrochemically deposited on titanium to improve its bio-properties. We compared the bio-properties for the different surface morphology coatings on titanium through a detailed surface characterization and upon in vitro cellular response of osteoblast-like cells MG63. The results of in vitro cellular response indicated that the uniform porous morphology of HAp layers on titanium exhibited higher bioactivity than the needle-like ones.