Grafting of calcium chelating functionalities onto PLA monofilament fiber surfaces

Mulky, Elias; Fortunato, Giuseppino; Hegemann, Dirk; Sague, Jorge; Heuberger, Roman; Frenz, Martin (2020). Grafting of calcium chelating functionalities onto PLA monofilament fiber surfaces. Biointerphases, 15(1), 011006. American Vacuum Society 10.1116/1.5129989

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Polymer surface grafting is widely used in the field of bone regeneration to increase calcium phosphate (CaP) adhesion, with the intent of improving mechanical properties of CaP-polymer composite cements. Reinforcement can be achieved using multiple combined functional groups and/or complex surface geometries that, however, concurrently influence multiple effects such as wetting, roughness, and interfacial strengthening. This study focused on the influence of a chelating group, namely aspartic acid, on the adsorption of divalent ions such as Ba²⁺ or Ca²⁺ onto poly-l-lactic acid (PLA) films. The films were analyzed using contact angle measurements and X-ray photoelectron spectroscopy. The adsorption of CaP and its interfacial mechanical properties were investigated using functionalized PLA monofilaments whose surface roughness was analyzed using white light interferometry. Mechanical analysis was conducted by performing pull-out tests. The surfaces were analyzed using scanning electron microscopy and energy dispersive X-ray spectroscopy. Using aspartic acid as a chelating group resulted in a 50 % increased adsorption of barium, an almost threefold increase in calcium coverage of the fiber compared to the control group and a twofold increase in interfacial stiffness. No significant increase in interfacial strength was determined, most likely due to the weakness of the CaP matrix, which was partially visible as residues on the monofilaments in the postfracture imaging. This study shows the potential of surfaces functionalized with aspartic acid as a simple alternative to complex polypeptide based functional groups for the adsorption of divalent ions such as calcium on poly-lactic acid in bone regenerating applications.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Applied Physics

UniBE Contributor:

Frenz, Martin

Subjects:

600 Technology > 620 Engineering
500 Science
500 Science > 530 Physics

ISSN:

1934-8630

Publisher:

American Vacuum Society

Language:

English

Submitter:

Simone Corry

Date Deposited:

08 Apr 2020 10:17

Last Modified:

08 Apr 2020 10:17

Publisher DOI:

10.1116/1.5129989

BORIS DOI:

10.7892/boris.141675

URI:

https://boris.unibe.ch/id/eprint/141675

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