Nanohydroxyapatite Electrodeposition onto Electrospun Nanofibers: Technique Overview and Tissue Engineering Applications

Abstract

Nanocomposite scaffolds based on the combination of polymeric nanofibers with nanohydroxyapatite are a promising approach within tissue engineering. With this strategy, it is possible to synthesize nanobiomaterials that combine the well-known benefits and advantages of polymer-based nanofibers with the osteointegrative, osteoinductive, and osteoconductive properties of nanohydroxyapatite, generating scaffolds with great potential for applications in regenerative medicine, especially as support for bone growth and regeneration. However, as efficiently incorporating nanohydroxyapatite into polymeric nanofibers is still a challenge, new methodologies have emerged for this purpose, such as electrodeposition, a fast, low-cost, adjustable, and reproducible technique capable of depositing coatings of nanohydroxyapatite on the outside of fibers, to improve scaffold bioactivity and cell–biomaterial interactions. In this short review paper, we provide an overview of the electrodeposition method, as well as a detailed discussion about the process of electrodepositing nanohydroxyapatite on the surface of polymer electrospun nanofibers. In addition, we present the main findings of the recent applications of polymeric micro/nanofibrous scaffolds coated with electrodeposited nanohydroxyapatite in tissue engineering. In conclusion, comments are provided about the future direction of nanohydroxyapatite electrodeposition onto polymeric nanofibers.

Evaluation of the Cathodic Electrodeposition Effectiveness of the Hydroxyapatite Layer Used in Surface Modification of Ti6Al4V-Based Biomaterials

“…The search for optimal conditions of the cathodic electrodeposition of HA on the surface of titanium implants/titanium alloys is one of the crucial issues that research on the design and manufacture of modern implants is focused on [ 16 , 30 , 51 , 60 , 61 , 62 ]. Electrodeposition is used in surface engineering electrochemical techniques, in which two electrodes (connected to an electrical generator) are immersed in an aqueous solution containing calcium and phosphate ions [ 16 , 17 , 26 , 63 ]. It should be noted that besides the deposition process conditions, the substrate’s type and properties directly impact the morphology, structure, and mechanical and biological properties of the produced HA layers.…”

“…The electrolyte used during the HA electrodeposition consisted of calcium nitrate tetrahydrate ((CaNO 3 ) 2 ·4H 2 O) and ammonium dihydrogen phosphate (NH 4 (H 2 PO 4 ) [ 17 , 51 , 52 , 64 , 65 , 66 , 67 ]. However, in all our experiments, the electrolyte mentioned above was enriched by adding ethylenediaminetetraacetic acid disodium salt (EDTA-2Na).…”

“…From the new generation implant construction point of view, the crucial issue is to equip their surface with a biocompatible, bioactive coating layer that adheres perfectly to the substrate (e.g., does not delaminate during use of the implant) [ 16 , 17 ]. The way to achieve this effect can be a production of an additional coating of a bone-like substance that is hydroxyapatite (HA), i.e., hydroxyl-containing forms of calcium phosphate, which promotes bone formation and growth [ 17 , 18 ]. Crystalline HA provides mechanical stability to the coating.…”

“…The plasma spraying, pulsed laser deposition, sol-gel method, PVD (sputter coat-ing), electrophoretic deposition, electrodeposition, and gas detonation deposition are usually used for producing an HA layer on implant surfaces [ 16 , 17 , 21 , 24 , 26 , 27 , 28 ]. Plasma spraying is the most popular, which has the advantage of being able to produce highly repeatable coatings.…”

“…The electrochemical technique is attractive due to its simplicity, low cost, uniformity of the produced coatings, and ability to precisely control the properties of the layers produced (chemical composition, thickness, structure) at low temperatures. It is suitable for coating surfaces with complex geometries [ 16 , 17 , 21 , 32 ]. The major limitation of the electrodeposition technique is the poor adhesion of the HA layer to the implant’s surface [ 16 , 21 , 33 ].…”