No abstract

The research of TiO 2 nanotubes (TNTs) in the field of biomedicine has been increasingly active. However, given the diversity of the nanoscale dimension and controversial reports, our understanding of the structure-property relationships of TNTs is not yet complete. In this paper, gradient TNTs with a wide diameter range of 20–350 nm were achieved by bipolar electrochemistry and utilized for a thorough high-throughput study of the effect of nanotube dimension and crystalline phase on protein adsorption and cell behaviors. Results indicated that protein adsorption escalated with nanotube dimension whereas cell proliferation and differentiation are preferred on small diameter (<70 nm) nanotubes. Large diameter anatase nanotubes had higher adsorption of serum proteins than as-prepared ones. But only as-prepared small diameter nanotubes presented slightly higher cell proliferation than corresponding annealed nanotubes whereas there was no discernible difference between as-prepared and annealed nanotubes on cell differentiation for the entire gradient. Those findings replenish previous research about how cell responses to TNTs with a wide diameter range and provide scientific guidance for the optimal design of biomedical materials.

The objective of this study is to explore the structure-property relationships of TiO 2 nanotubes (TNTs) with different crystalline phases that link to protein adsorption and cell responses. Given the formation of intact rutile nanotubular structures by furnace annealing is challenge, a combination of furnace annealing and flame annealing is employed for the preparation of rutile TNTs. TNTs with pure anatase phase and mixed anatase/rutile phases are obtained by simple furnace annealing of amorphous TNTs. Results show that BSA and FBS adsorptions are greatly enhanced on rutile TNTs, whereas no discernable difference on other crystalline phases. Rutile TNTs also present highest adsorption of fibronectin and collagen which are diminished on anatase and dual anatase-rutile phases. Interestingly, however, there is no significant difference in cell proliferation or differentiation on TNTs with different crystallites. Scrutinization of the surface properties involved in protein adsorption and cell activities, a synergistic effect of surface charge, hydroxyl groups, and roughness is found on protein adsorption which further regulates cell behaviors. Those findings provide a better understanding of the structure-property relationships of titanium-based biomaterials.

The cellular mechanism underlying bacteria responses to silver nanoparticles (AgNPs) has not been fully elucidated. Especially, it is difficult to distinguish the contact killing from release killing as Ag+ releases from AgNPs. In this paper, AgNPs gradient was designed for evaluating the size effect of AgNPs on contact killing. A size gradient of AgNPs (5–45 nm) was achieved on TiO2 nanotubes (TNTs) by rational design of bipolar electrochemical reaction, including applied voltage, electrolyte concentration, and sample size. High-throughput investigation of cellular responses showed that the smallest AgNPs were the most efficient in suppressing bacteria whereas the largest AgNPs were more favorable for MC3T3-E1 cell adhesion and proliferation. As Ag+ concentration was the same for the entire gradient, the difference in cellular responses was dominated by the contact effect (rather than difference in released Ag+) which was tuned by AgNPs size. This method offers new prospect for efficient evaluation of the contact effect of nanoparticles, such as Ag, Au, and Cu.

Because polymers containing benzyl chloromethyl groups are easily modified for functional production, the dispersion polymerization of acrylamide, 4-vinylbenzyl chloride, and N,N-methylene bisacrylamide in dimethylformamide initiated with a,a-azobisisobutyronitrile was carried out to produce amphiphilic microspheres containing benzyl chloromethyl groups. The structure of the amphiphilic microspheres was determined by IR and 1 H-NMR spectroscopy. The polymerization conditions, the temperature, amount of crosslinking agent, and initiator included, were optimized. The size distribution of the microspheres after swelling equilibrium ranged from 4 to 62 lm. The swelling behavior of the microspheres was also investigated. The increase in temperature and the decrease in salinity caused a gradual increase in the swelling ratio. The prepared microspheres were transported uniformly in porous media when the permeability was 0.436 lm 2 . The oil displacement experiments indicated that amphiphilic microspheres had the ability to enhance oil recovery under homogeneous and heterogeneous conditions but was more suitable for heterogeneous formation.