Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jan 10;16(2):682.
doi: 10.3390/ma16020682.

A Novel PLLA/MgF2 Coating on Mg Alloy by Ultrasonic Atomization Spraying for Controlling Degradation and Improving Biocompatibility

Wenpeng Peng  1   2   3 , Yizhe Chen  4 , Hongde Fan  4 , Shanshan Chen  5 , Hui Wang  4 , Xiang Song  1   2
Affiliations

A Novel PLLA/MgF2 Coating on Mg Alloy by Ultrasonic Atomization Spraying for Controlling Degradation and Improving Biocompatibility

Wenpeng Peng et al. Materials (Basel). .

Abstract

Problems of rapid degradation and poor biocompatibility (endothelialization and hemocompatibility) limit magnesium (Mg) alloy's further applications in vascular stents. To solve these problems, a novel composite coating was designed on Mg alloy via a two-step method. First, a Mg alloy sample was immersed in hydrofluoric acid. Then, a poly-l-lactic acid (PLLA) coating was made by ultrasonic atomization spraying with 5 and 10 layers (referred to as PLLA(5)-HF-Mg and PLLA(10)-HF-Mg). Characterizations were analyzed from the microstructure, element distribution, and wettability. The degradation behavior was tested with an electrochemical test and immersion test. Endothelialization was investigated using human umbilical vein endothelial cells (HUVECs). Hemocompatibility was examined with a platelet adhesion test. The results showed that the PLLA coating could not only cover the surface, but also could permeate through and cover the holes on the MgF2 layer, mechanically locked with the substrate. Thus, the composite coating had higher corrosion resistance. The PLLA/MgF2 coating, especially on PLLA(10)-HF-Mg, enhanced HUVECs' viability and growth. While incubated with platelets, the PLLA/MgF2 coating, especially on PLLA(10)-HF-Mg, had the lowest platelet adhesion number and activity. Taken together, the novel PLLA/MgF2 coating controls Mg alloy's degradation by spraying different layers of PLLA, resulting in better endothelialization and hemocompatibility, providing a promising candidate for cardiovascular stents.

Keywords: biocompatibility; biodegradable; degradation; hydrofluoric acid; magnesium alloys; poly-l-lactic acid.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Preparing process of samples.
Figure 2
Figure 2
Cell testing of coated and bare Mg alloys (A) Processing of testing cell adhesion, (B) Processing of testing cell viability.
Figure 3
Figure 3
SEM images of (a) bare Mg alloy, (b) HF-Mg and (c) PLLA (5)-HF-Mg, (d) PLLA (10)-HF-Mg.
Figure 4
Figure 4
Elemental composition of the surface of (a) bare Mg alloy, (b) HF-Mg and (c) PLLA (5)-HF-Mg, (d) PLLA (10)-HF-Mg.
Figure 5
Figure 5
SEM micrograph of the cross-section of three coated samples (a) HF- Mg, (b) PLLA (5)-HF-Mg, (c) PLLA (10)-HF-Mg.
Figure 6
Figure 6
Water contact angle of coated and bare Mg alloys. Values are mean ± standard deviation (n = 3).
Figure 7
Figure 7
PDP curves of coated and bare Mg alloy samples in SBF.
Figure 8
Figure 8
pH values of SBF solution for coated and bare Mg alloy over time after immersion.
Figure 9
Figure 9
SEM image of all samples after immersion in SBF for 15 days (a) bare Mg, (b) HF-Mg and (c) PLLA (5)-HF-Mg, (d) PLLA (10)-HF-Mg.
Figure 10
Figure 10
Corrosion surface components of all samples after immersion in SBF for 15 days analyzed by EDS.
Figure 11
Figure 11
Fluorescence images of HUVECs attached directly on bare Mg and coated Mg alloy after in vitro culture for 24 h, where live cells fluoresce green and dead cells fluoresce red ((a) bare Mg (b) HF-Mg (c) PLLA (5)-HF-Mg (d) PLLA (10)-HF-Mg).
Figure 12
Figure 12
In vitro cell vitality tests of Mg alloy extracts on HUVECs. (A: bare Mg alloy; B: HF-Mg; C: PLLA (5)-HF-Mg; D: PLLA (10)-HF-Mg). Values are mean ± standard deviation (n = 3). * p < 0.05, *** p < 0.001. ns: no significance.
Figure 13
Figure 13
(A) Platelet adhesion tests of (a) bare Mg alloy (b) HF-Mg (c) PLLA (5)-HF-Mg (d) PLLA (10)-HF-Mg. (B) Number of adhered platelets/SEM Image, (** p < 0.01, *** p < 0.001).
Figure 14
Figure 14
Mechanism of Mg alloys’ degradation controlled by different coatings.
See this image and copyright information in PMC

References

    1. The writing committee of the report on cardiovascular health diseases in China. Chin. Circ. J. 2020;35:833–854.
    1. Fontes I., Barrow D. From sirolimus to the Cypher stent: Stages of the victory against restenosis. Ann. Cardiol. Angeiol. 2004;53:3–8. doi: 10.1016/S0003-3928(04)90001-7. - DOI - PubMed
    1. Dorr O., Liebetrau C., Wiebe J., Hecker F., Rixe J., Mollmann H., Hamm C., Nef H. Bioresorbable scaffolds for the treatment of in-stent restenosis. Heart Vessel. 2015;30:265–269. doi: 10.1007/s00380-013-0464-5. - DOI - PubMed
    1. Wenaweser P., Daemen J., Zwahlen M., van Domburg R., Juni P., Vaina S., Hellige G., Tsuchida K., Morger C., Boersma E., et al. Incidence and correlates of drug-eluting stent thrombosis in routine clinical practice—4-year results from a large 2-institutional cohort study. J. Am. Coll. Cardiol. 2008;52:1134–1140. doi: 10.1016/j.jacc.2008.07.006. - DOI - PubMed
    1. Beshchasna N., Saqib M., Kraskiewicz H., Wasyluk L., Kuzmin O., Duta O.C., Ficai D., Ghizdavet Z., Marin A., Ficai A., et al. Recent Advances in Manufacturing Innovative Stents. Pharmaceutics. 2020;12:349. doi: 10.3390/pharmaceutics12040349. - DOI - PMC - PubMed