Development and Investigation of Mesoporous Bioactive Glass/Zein Coatings Electrodeposited on Titanium Alloy for Biomedical Applications

Abstract

The objective of the present work was the development of cathodic electrophoretic deposition (EPD) to obtain composite coatings of mesoporous sol–gel glass (MSGG) particles embedded in a zein matrix on Ti-13Nb-13Zr substrates. To deposit robust and repeatable coatings, a direct current EPD and pulsed direct current EPD as well as the deposition kinetics were investigated, including the deposition yield and deposition rate. The stability of the suspension was determined based on the zeta potential and conductivity. Macroscopically homogeneous coatings with a thickness of about 10 µm and various volume fractions of MSGG were subjected to further examination. Coatings were uniform, exhibiting open porosity and showing excellent adhesion to the substrates. Both zein and MSGG particles revealed an amorphous structure. The coated substrates demonstrated greater resistance to electrochemical corrosion in Ringer's electrolyte in comparison with the virgin (non-coated) substrate. The coatings showed high roughness and moderate hydrophilicity. The incubation of the coated substrates in concentrated 1.5 simulated body fluid (1.5SBF) showed the formation of carbonate hydroxyapatite. The composite coatings showed improved antibacterial properties against gram-negative E. coli and gram-positive S. aureus bacteria compared to pure zein coatings. Electrophoretic MSGG/zein composite coatings should be further investigated in terms of their osteoconductive behavior, to confirm their suitability for medical applications in orthopedics.

Influence of Mesoporous Bioactive Glass Particles Doped with Cu and Mg on the Microstructure and Properties of Zein-Based Coatings Obtained by Electrophoretic Deposition

“…Despite the low stability of the suspensions, coatings were satisfactorily deposited on the cathode. As we described in a previous paper, 47 the mechanism of coating deposition, in which zein binds to MSGG particles, has a significant influence. A similar mechanism occurred in the co-deposition of zein with the MSGG-Cu and MSGG-Cu-Mg particles.…”

“…24,26,53 Additionally, the incorporation of glycerin into the solution increases the plasticity of the zein formed base of the coatings. 54 In our earlier work, 47 we showed that the solution of EtOH/H 2 O in the ratio of 9/1 and 0.024 kg dm −3 glycerol, 0.2 kg dm −3 zein and 0.04 kg dm −3 reference MSGG is optimal for the fabrication of uniform MSGG/zein coatings with high adhesion to the substrates. Therefore, to study the effect of the incorporation of Cu and Mg to glasses on EPD in this study, zein solutions with MSGG-Cu and MSGG-Cu-Mg particles in various contents, but the same as in the case of reference MSGG, 47 0.01 kg dm −3 , 0.04 kg dm −3 and 0.08 kg dm −3 , were used.…”

“…The bioactive glass synthesis protocol was based on our previous work. 47 Firstly, the 5.5% (w/v) surfactant solution was prepared by completely dissolving the relevant Pluronic in ethanol. After obtaining a clear solution, HCl (catalyst for the hydrolysis and condensation reactions) was slowly added followed by 5 min of stirring before adding TEOS.…”

“…Our previous work 47 focused on EPD conditions to obtain homogeneous mesoporous sol-gel glass (MSGG)/zein coatings with high adhesion to titanium alloy substrates. The glass used had a reference chemical composition (70 SiO 2 , 26 CaO, 4 P 2 O 5 , % mol) and did not contain Mg and Cu.…”

Fabrication of Zein‐Based Fibrous Scaffolds for Biomedical Applications—A Review

“…Physical, structural condition Amorphous [28] Denaturation (°C) 80.32-87.31 [29] Glass transition (°C) 165 [30,31] Melting point (°C) 266-283 [32] Thermal degradation (°C) 320 [30,33] Degree of polymerization 210-245 [17] Isoelectric point pH 6.2 [34] Density (g cm −3 ) 1 . 2 3 g c m −3 [35,36] Partial specific volume 0.771 [37] Particle size (nm) 150-550 [38][39][40] Water content (g/100 g) 10.5, at a water activity of 0.753 in 25 °C [41] Solubility Almost impossible to dissolve in 100% ethanol, acetone, or water; Soluble in acetone solutions (60-80% v/v), extremely concentrated urea, and glycols; Soluble in alkaline solutions of pH ≥ 11.5 [20,35,42] Viscosity coefficient 25 [43] Diffusion coefficient (m 2 s −1 ) 3.7× 10 −14 [43] Flavor Tasteless [44] Odor Odorless [45] Color Yellowish [46] Composition (%) Glutamine 21-26 Proline 10 Leucine 20 Alanine 10 [47] zein is easily transformed into nanofibers, nanoribbons, [53] nanoparticles, [54] microspheres, [55] thin coatings, [56] and Janus fibers. [57] Zein possesses exceptional characteristics like flexibility, high surface area, low cytotoxicity, biocompatibility, and biodegradability.…”