Photodeposition of Hydroxyapatite into a Titanium Dioxide Nanotubular Layer Using Ca(EDTA) Complex Decomposition

A new photocatalytic hydroxyapatite (HA) synthesis method has been developed. This method is based on the unique ability of the TiO2 photocatalyst to decompose the Ca(EDTA) complex under UV illumination. As a result, released Ca2+ ions react with PO43− ions forming the HA particles. The photocatalytic formation of hydroxyapatite is found to have a fractional order, which may indicate the complex reaction mechanism and the presence of several limiting stages. The TNT-HA samples were studied by XRD, FTIR, SEM, GDOES, and biocompatibility study. High biocompatibility of the surfaces is proven by pre-osteoblast cell growth

Periodic Self-Assembly of Poly(ethyleneimine)–poly(4-styrenesulfonate) Complex Coacervate Membranes

Coacervation is a self-assembly strategy based on the complexation of polyelectrolytes, which is utilized in biomedicine and agriculture, as well as automotive and textile industries. In this paper, we developed a new approach to the on-demand periodic formation of polyelectrolyte complexes through a Liesegang-type hierarchical organization. Adjustment of reaction conditions allows us to assemble materials with a tunable spatiotemporal geometry and establish materials’ production cycles with a regulated periodicity. The proposed methodology allows the membrane to self-assemble when striving to reach balance and self-heal after exposure to external stimuli, such as potential difference and high pH. Using chronopotentiometry, K+ ion permeability behavior of the PEI–PSS coacervate membranes was demonstrated. The periodically self-assembled polyelectrolyte nanomembranes could further be integrated into novel energy storage devices and intelligent biocompatible membranes for bionics, soft nanorobotics, biosensing, and biocomputing

Biomimetic materials based on hydroxyapatite patterns for studying extracellular cell communication

The study of cellular ion channels forms a basic understanding of healthy organ functioning and the body as a whole; however, the native role of signal transmission through ion channels between cells remains unclear. The success of the signal transmission investigation depends on the methods and materials used. Therefore, it is necessary to develop a new approach and system for studying detecting cell–cell communication. In this work, we suggest the system of hydroxyapatite patterns demonstrating piezoresponse in conjunction with fiber-based biosensors for detection of electrical signaling in cellular communities. Our system does not disrupt the integrity of cell membrane. The cells are located on self-assembled hydroxyapatite patterns forming the tissue patterns and communicating via spatially propagating waves of calcium, sodium, and potassium ions. These waves result from positive feedback caused by the activation of Ca2+ channels. The fiber-based ion-selective microelectrodes fixed above the patterns are used to detect the sodium, potassium, calcium ion currents in the extracellular space. We use norepinephrine to activate the Ca2+ channels result in intracellular Ca2+ release between the cell communities on different patterns. This system could be perspective as an efficient platform to lab-on-a-chip study as well as fundamental understanding of cellular communication during regeneration