Surface Modification of Poly(lactic-co-glycolic acid) Microspheres with Enhanced Hydrophilicity and Dispersibility for Arterial Embolization

Abstract

In this study, a series of poly(lactic-co-glycolic acid) (PLGA) microspheres with different particle sizes for arterial embolization surgery were prepared. The polydopamine (PDA) and polydopamine/polyethyleneimine (PDA/PEI) were respectively coated on the PLGA microspheres as shells, in order to improve the hydrophilicity and dispersibility of PLGA embolization microspheres. After modification, with the introduction of PDA and PEI, many hydrophilic hydroxyl and amine groups appeared on the surface of the PLGA@PDA and PLGA@PDA/PEI microspheres. SEM images showed the morphologies, sizes, and changes of the as-prepared microspheres. Meanwhile, the XPS and FT-IR spectra demonstrated the successful modification of the PDA and PEI. Water contact angles (WCAs) of the PLGA@PDA and PLGA@PDA/PEI microspheres became smaller, indicating a certain improvement in surface hydrophilicity. In addition, the results of in vitro cytotoxicity showed that modification had little effect on the biosafety of the microspheres. The modified PLGA microspheres suggest a promising prospective application in biomedical field, as the modified microspheres can reduce difficulties in embolization surgery.

Keywords: functional; microspheres; poly(lactic-co-glycolic acid); surface modification.

Scheme 1

The fabrication process of poly(lactic-co-glycolic acid) (PLGA) @ polydopamine (PDA) and PLGA@PDA/polyethyleneimine (PEI) microspheres.

Figure 1

The optical micrograph (a), digital photograph (b), and SEM micrograph (c) of PLGA microspheres.

Figure 2

The optical micrographs of PLGA microspheres with different size fractions. (a) 0~200 µm; (b) 200~300 µm; (c) 300~400 µm; (d) 400~500 µm; (e) 500~600 µm; (f) 600~700 µm; (g) 700~800 µm; (h) 800~900 µm; (i) 900~1000 µm.

Figure 3

Color and size of (a) PLGA microspheres, (b) PLGA@PDA microspheres and (c) PLGA@PDA/PEI microspheres.

Figure 4

SEM micrographs of (a) PLGA microspheres, (b) PLGA@PDA microspheres, and (c) PLGA@PDA/PEI microspheres.

Figure 5

Corrosion of PLGA microspheres (a) and PLGA@PDA microspheres (b) in dichloromethane (DCM).

Figure 6

FTIR spectra with a scale of 4000~500 cm⁻¹ (a) and 2000~1000 cm⁻¹ (b) of the PLGA microspheres, PLGA@PDA microspheres, and PLGA@PDA/PEI microspheres.

Figure 7

(a) The total XPS survey spectra of the PLGA microspheres, PLGA@PDA microspheres, and PLGA@PDA/PEI microspheres; (b) the N1s spectra of PLGA@PDA microspheres; (c) the N1s spectra of the PLGA@PDA/PEI microspheres.

Figure 8

The water contact angles (WCAs) of (a) PLGA microspheres, (b) PLGA@PDA microspheres, and (c) PLGA@PDA/PEI microspheres.

Figure 9

Cell viability after treatment with blank PLGA, PLGA@PDA and PLGA@PDA/PEI microspheres at the concentration of (a) 37.25 μg/mL; (b) 62.5 μg/mL; (c) 125 μg/mL; (d) 250 μg/mL; (e) 500 μg/mL and (f) 1000 μg/mL.