Visualization of supramolecular structure of Pluronic F127 micellar hydrogels using cryo-TEM

Author(s)

da Silva, Laura C. E. ^[1] ; Borges, Antonio C. ^[2] ; de Oliveira, Marcelo G. ^[1] ; de Farias, Marcelo A. ^[2]

Affiliation

^[1] Univ Estadual Campinas, Univ Campinas, Inst Chem, BR-13083970 Campinas, SP - Brazil

^[2] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Nanotechnol Natl Lab LNNano, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: METHODSX; v. 7, 2020.
• Web of Science Citations: 0

Abstract

Pluronic (R) F127 micellar hydrogels are of growing interest to the biomedical field due to their versatility as drug delivery systems. Pluronic (R) F127 is a symmetric and amphiphilic triblock copolymer which in aqueous medium self-assembles into micelles that pack togetherwith increasing temperature or concentration, leading to non-flowable hydrogels. The microstructure of these hydrogels is usually investigated by small-angle X-ray scattering, which is not a readily available technique. Conversely, cryo-TEM is a widespread technique used for investigating the morphology of aqueous systems. In the case of Pluronic (R) F127 micellar systems, the elevated viscosity poses a significant challenge for specimen preparation and, consequently, for cryo-TEM observation. Herein, we show a trustworthy, inexpensive and readily available methodology for preparing specimens of highly viscous micellar solutions and non-flowable hydrogels using an automated vitrification system. With this methodology we were able to visualize not only the morphology of individual Pluronic (R) F127 micelles -but also the supramolecular structure evolution as a function of concentration. This methodology opens up a wide range of opportunities for hydrogel characterization, although additional systematic studies might be required in order to optimize and replicate it for similar systems. (C) 2020 The Authors. Published by Elsevier B.V. (AU)

• FAPESP's process: 16/02414-5 - Topical and absorbable biomaterials for the local nitric oxide release
• Grantee: Marcelo Ganzarolli de Oliveira
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/14142-5 - Hybrid hydrogels for local and prolonged nitric oxide release
• Grantee: Laura Caetano Escobar da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral