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Imparting superhydrophobicity to biodegradable poly(lactide-co-glycolide) electrospun meshes.

Kaplan JA, Lei H, Liu R, Padera R, Colson YL, Grinstaff MW - Biomacromolecules (2014)

Bottom Line: Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers.Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties.Contact angles as high as 160° are obtained with 30% polymer dopant.

View Article: PubMed Central - PubMed

Affiliation: Departments of Biomedical Engineering and Chemistry, Boston University , Boston, Massachusetts 02215, United States.

ABSTRACT
The synthesis of a family of new poly(lactic acid-co-glycerol monostearate) (PLA-PGC18) copolymers and their use as biodegradable polymer dopants is reported to enhance the hydrophobicity of poly(lactic acid-co-glycolic acid) (PLGA) nonwoven meshes. Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers. Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties. Contact angles as high as 160° are obtained with 30% polymer dopant. Lastly, these meshes are nontoxic, as determined by an NIH/3T3 cell biocompatibility assay, and displayed a minimal foreign body response when implanted in mice. In summary, a general method for constructing biodegradable fibrous meshes with tunable hydrophobicity is described for use in tissue engineering and drug delivery applications.

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Influence of fiber size, copolymer dopant species, andpercentdoping on the apparent advancing (dark shade) and receding (lightshade) water contact angles of PLGA-based microfiber meshes (PLGA,white; PLA-PGC18 (90:10), blue; PLA–PGC18 (60:40), orange). Errorbars represent standard deviation (n = 10).
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fig2: Influence of fiber size, copolymer dopant species, andpercentdoping on the apparent advancing (dark shade) and receding (lightshade) water contact angles of PLGA-based microfiber meshes (PLGA,white; PLA-PGC18 (90:10), blue; PLA–PGC18 (60:40), orange). Errorbars represent standard deviation (n = 10).

Mentions: Electrospinning was accomplished by loading thesepolymer solutionsinto a syringe configured in a syringe pump (Q =3.0 mL/h) and applying a high voltage to the tip of the syringe needleas the solution was collected onto a rotating drum. Fiber size wascontrolled by varying the total polymer concentration of the solutions:30 wt % solutions resulted in small (2.5–3.5 μm) diameterfibers, whereas 40 wt % solutions resulted in large (6.5–7.5μm) fibers (Figure 1). The polymer dopantsselected for electrospinning with PLGA were the PLA–PGC18 (90:10) and PLA–PGC18 (60:40) copolymers,and SEM images of all of the meshes can be found in Figures 1, S1, S2, and S3. Wehypothesized that increasing copolymer composition (i.e., C18 content) would raise the apparent water contact angle to affordsuperhydrophobic meshes. The apparent advancing and receding watercontact angles on large-fiber electrospun pure PLGA meshes were ∼110and 81°, and the contact angle increased as fiber size was reducedor as copolymer doping was increased such that advancing contact anglesas high as ∼162° (and receding as high as 145°) wereobtained for small-fiber PLGA doped with 30% PLA–C18 (60:40) (Figures 1 and 2; see Figure S4 for the static contactangles). The difference between the values (i.e., hysteresis) forthe advancing and receding contact angles decreased once the materialstransitioned from hydrophobic to superhydrophobic. Reducing the fiberdiameter enhanced mesh hydrophobicity (i.e., greater apparent advancingand static water contact angles) by decreasing the polymer surfacefill fraction and increasing the air fraction exposed at the surface.Likewise, minimizing the mesh surface roughness via melting the meshesinto films also dramatically reduced the water contact angles to 100°or lower for the respective compositions (see Supporting Information Figure S5). The degree of hydrophobicitywas also dependent on dopant copolymer composition, with an increasein hydrophobicity as the lactide–C18 ratio increased(Figure 2). In contrast, electrospun meshesdoped with 30% of the free hydroxyl copolymer PLA–PGC-OH (60:40)did not appreciably enhance mesh hydrophobicity (WCA ≈ 120± 4° for 2.5–3.5 μm fibers; Supporting Information Figure S3),confirming that the enhancement in hydrophobicity was due to the C18 moiety. The fibers within these meshes were relatively smoothand randomly oriented, as revealed by scanning electron microscopy.However, in the extreme case of small fibers doped with 30% PLA–PGC18 (60:40), a tertiary web-like structure developed on thefiber surface, adding to the overall surface roughness and resultingin a high apparent contact angle (Figure 3b).


Imparting superhydrophobicity to biodegradable poly(lactide-co-glycolide) electrospun meshes.

Kaplan JA, Lei H, Liu R, Padera R, Colson YL, Grinstaff MW - Biomacromolecules (2014)

Influence of fiber size, copolymer dopant species, andpercentdoping on the apparent advancing (dark shade) and receding (lightshade) water contact angles of PLGA-based microfiber meshes (PLGA,white; PLA-PGC18 (90:10), blue; PLA–PGC18 (60:40), orange). Errorbars represent standard deviation (n = 10).
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Related In: Results  -  Collection

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fig2: Influence of fiber size, copolymer dopant species, andpercentdoping on the apparent advancing (dark shade) and receding (lightshade) water contact angles of PLGA-based microfiber meshes (PLGA,white; PLA-PGC18 (90:10), blue; PLA–PGC18 (60:40), orange). Errorbars represent standard deviation (n = 10).
Mentions: Electrospinning was accomplished by loading thesepolymer solutionsinto a syringe configured in a syringe pump (Q =3.0 mL/h) and applying a high voltage to the tip of the syringe needleas the solution was collected onto a rotating drum. Fiber size wascontrolled by varying the total polymer concentration of the solutions:30 wt % solutions resulted in small (2.5–3.5 μm) diameterfibers, whereas 40 wt % solutions resulted in large (6.5–7.5μm) fibers (Figure 1). The polymer dopantsselected for electrospinning with PLGA were the PLA–PGC18 (90:10) and PLA–PGC18 (60:40) copolymers,and SEM images of all of the meshes can be found in Figures 1, S1, S2, and S3. Wehypothesized that increasing copolymer composition (i.e., C18 content) would raise the apparent water contact angle to affordsuperhydrophobic meshes. The apparent advancing and receding watercontact angles on large-fiber electrospun pure PLGA meshes were ∼110and 81°, and the contact angle increased as fiber size was reducedor as copolymer doping was increased such that advancing contact anglesas high as ∼162° (and receding as high as 145°) wereobtained for small-fiber PLGA doped with 30% PLA–C18 (60:40) (Figures 1 and 2; see Figure S4 for the static contactangles). The difference between the values (i.e., hysteresis) forthe advancing and receding contact angles decreased once the materialstransitioned from hydrophobic to superhydrophobic. Reducing the fiberdiameter enhanced mesh hydrophobicity (i.e., greater apparent advancingand static water contact angles) by decreasing the polymer surfacefill fraction and increasing the air fraction exposed at the surface.Likewise, minimizing the mesh surface roughness via melting the meshesinto films also dramatically reduced the water contact angles to 100°or lower for the respective compositions (see Supporting Information Figure S5). The degree of hydrophobicitywas also dependent on dopant copolymer composition, with an increasein hydrophobicity as the lactide–C18 ratio increased(Figure 2). In contrast, electrospun meshesdoped with 30% of the free hydroxyl copolymer PLA–PGC-OH (60:40)did not appreciably enhance mesh hydrophobicity (WCA ≈ 120± 4° for 2.5–3.5 μm fibers; Supporting Information Figure S3),confirming that the enhancement in hydrophobicity was due to the C18 moiety. The fibers within these meshes were relatively smoothand randomly oriented, as revealed by scanning electron microscopy.However, in the extreme case of small fibers doped with 30% PLA–PGC18 (60:40), a tertiary web-like structure developed on thefiber surface, adding to the overall surface roughness and resultingin a high apparent contact angle (Figure 3b).

Bottom Line: Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers.Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties.Contact angles as high as 160° are obtained with 30% polymer dopant.

View Article: PubMed Central - PubMed

Affiliation: Departments of Biomedical Engineering and Chemistry, Boston University , Boston, Massachusetts 02215, United States.

ABSTRACT
The synthesis of a family of new poly(lactic acid-co-glycerol monostearate) (PLA-PGC18) copolymers and their use as biodegradable polymer dopants is reported to enhance the hydrophobicity of poly(lactic acid-co-glycolic acid) (PLGA) nonwoven meshes. Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers. Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties. Contact angles as high as 160° are obtained with 30% polymer dopant. Lastly, these meshes are nontoxic, as determined by an NIH/3T3 cell biocompatibility assay, and displayed a minimal foreign body response when implanted in mice. In summary, a general method for constructing biodegradable fibrous meshes with tunable hydrophobicity is described for use in tissue engineering and drug delivery applications.

Show MeSH
Related in: MedlinePlus