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Nanostructured Fe-Mn and Fe-Mn-Zn metal scaffolds were generated through a well-controlled selective leaching process in order to fulfill the growing demand for adjustable degradation rates and improved cellular response of resorbable materials. Mouse bone marrow mesenchymal stem cells (D1 ORL UVA) were seeded onto eleven, carefully chosen nanoporous surfaces for 24 h in vitro. Using a combination of fluorescence microscopy, scanning electron microscopy (SEM), and an MTS assay, it was discovered that scaffolds with nanoscale roughened surfaces had increased cell attachment by up to 123% compared to polished smooth Fe-Mn surfaces. Significant cell spreading and construction of cell multilayers were also apparent after 24 h, suggesting better adhesion. Additionally, static electrochemical polarization experiments revealed an improvement of up to 26% in the actual rate of biodegradation for Fe-Mn surface-modified materials. However, any residual concentration of zinc after leaching was shown to slightly increase corrosion resistance. The results demonstrate that selectively leached, nanostructured Fe-Mn surfaces have the potential of being tailored to a diverse set of transient implant scenarios, while also effectively boosting overall biocompatibility, initial cell attachment, and degradation rate. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1747-1758, 2016.

Bioresorbable iron‐manganese alloys (Fe‐30%Mn) are considered as one of the next‐generation resorbable materials for orthopedic applications. Previous in vitro study showed that Fe30Mn scaffolds with 10% porosity displayed strong mechanical properties and adequate degradation rate without severe cytotoxicity effect. However, the cellular compatibility of these alloys in terms of cell‐to‐cell and alloy‐to‐cell interactions is not ideal. Collagen is the most abundant protein in human bone, providing structural support beneficial to bone healing. We hypothesized that coating collagen on Fe30Mn can improve osteointegration or activities promoting cell adhesion, migration, and proliferation, as the alloy degrades. After preparing collagen coating on Fe‐30Mn via spin coating, we conducted a corrosion test and a direct cytotoxicity test on four Fe30Mn groups: non‐porous and 10% porosity, with and without collagen coating. Furthermore, we evaluated and compared the morphologies of cells over a period of 7 days. Results showed that there was no significant difference between the collagen‐coated and non‐coated groups in corrosion rates, yet a significant decrease from the porous non‐coated group to the porous collagen‐coated group in cytotoxicity level was found. Cell morphology on the porous non‐coated group displayed round shape, whereas that on the porous collagen‐coated group displayed flattened spreading. The study showed that the collagen coating significantly increased the initial cell viability and adhesion for both the porous and non‐porous groups without impeding their degradation rates. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:523–535, 2020

In an attempt to understand the structure and dynamics of ssDNA on graphene based surfaces, we performed all-atom implicit solvent molecular dynamics simulations of ssDNA on graphene and graphene oxide (GO) surfaces. Simulations indicate that adsorption of poly(A), poly(T) and poly (AT) have similar mechanisms of adsorption to free standing graphitic flakes, which are governed by a surface oxygen content. Specifically, higher oxygen content of a surface leads to decrease in persistence length of ssDNA. However, the role of DNA sequence on the physisorption mechanism is minimal.

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