Ultra-Structural Study of the Laminin-Apatite Composite Layer Formed on Ethylene-Vinyl Alcohol Copolymer by a Biomimetic Process

Abstract

Mechanism of formation of a laminin-apatite composite layer on the surface of an ethylene-vinyl alcohol copolymer (EVOH) using a liquid phase coating process was investigated by transmission electron microscopy (TEM). In this coating process, an EVOH substrate is alternately dipped in calcium and phosphate solutions, and then immersed in a laminin-containing calcium phosphate (LCP) solution. From the results obtained by the present study, formation of the laminin-apatite composite layer on EVOH is likely to proceed via the following events. By the alternate dipping process, particulate amorphous calcium phosphate, which is a precursor of apatite, was deposited onto the EVOH surface. When the specimen was subsequently immersed in the LCP solution, the amorphous calcium phosphate on the specimen transformed itself into needle-like apatite crystal, and then grew into a layer. During this process, laminin molecules contained in the LCP solution were incorporated into a matrix of the apatite crystals to produce a laminin-apatite composite layer on the EVOH surface.

Improved gene transfer efficiency of a DNA-lipid-apatite composite layer by controlling the layer molecular composition

“…This alternate dipping process was performed three times. As a result of this treatment, nanoparticles of ACP, which is a precursor of Ap [33], were precoated onto each substrate surface [39]. The ACP-precoated substrate was then sterilized by exposure to ethylene oxide gas followed by aseptic immersion in the coprecipitation solution (3 mL) prepared in the preceding section for 24 h at 25 • C. Within 24 h of immersion in the coprecipitation solution, a micro-thick DLp-Ap layer grew on the ACP-precoated substrate via coprecipitation of Ap nanocrystals and DLp complexes [27,28].…”

One-step biomimetic coprecipitation method to form calcium phosphate and hemoglobin composite nanoparticles for biosensing application

“…Firstly, substrates were modified with CaP precursors [13][14][15][16][17][18][19][20] or functional groups [21,22] which effectively induce CaP nucleation; secondly, these substrates were immersed in CP solution containing proteins for a certain time, as a result, a CaP/protein composite layer formed on the material surface. In this case, CaP/Hb composites formed on the surface of GCE via one step coprecipitation without introducing any precursors or functional groups.…”

“…It is generally fulfilled by immersing substrates in a protein-containing supersaturated calcium phosphate solution for a certain time. However, the researches mostly focused on the study of mechanism of biomimetic coprecipitation process and their biomedical applications [13][14][15][16][17][18][19][20][21][22]. In this paper, we report the one-step preparation of CaP/Hb composite nanoparticles on the surface of GCE by biomimetic coprecipitation, and their use for bioelectronic sensing applications.…”

Development of apatite-based composites by a biomimetic process for biomedical applications

“…The nanoparticles of ACP are introduced onto a polymer surface by a simplified alternate dipping treatment, 8) dipping the polymer in calcium and phosphate ion solutions only three times. 56) When the ACP-modified polymer is subsequently immersed in a supersaturated calcium phosphate solution such as SBF, the ACP acts as a precursor of apatite and induces apatite nucleation within only 3 h. 34) This is because apatite has the lowest solubility and has thermodynamically the most stable phase among all the calcium phosphates in a neutral solution. 4) Once apatite is nucleated, it grows spontaneously into an apatite layer.…”