Photo-Cleavable Peptide-Poly(Ethylene Glycol) Conjugate Surfaces for Light-Guided Control of Cell Adhesion

Photo-responsive cell attachment surfaces can simplify patterning and recovery of cells in microdevices for medicinal and pharmaceutical research. We developed a photo-responsive surface for controlling the attachment and release of adherent cells on a substrate under light-guidance. The surface comprises a poly(ethylene glycol) (PEG)-based photocleavable material that can conjugate with cell-adhesive peptides. Surface-bound peptides were released by photocleavage in the light-exposed region, where the cell attachment was subsequently suppressed by the exposed PEG. Simultaneously, cells selectively adhered to the peptide surface at the unexposed microscale region. After culture, the adhered and spread cells were released by exposure to a light with nontoxic dose level. Thus, the present surface can easily create both cell-adhesive and non-cell-adhesive regions on the substrate by single irradiation of the light pattern, and the adhered cells were selectively released from the light-exposed region on the cell micropattern without damage. This study shows that the photo-responsive surface can serve as a facile platform for the remote-control of patterning and recovery of adherent cells in microdevices.

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Structural engineering to control density, conformation, and bioactivity of the poly(ethylene glycol)-grafted poly(urethane urea) scaffolds

Journal of Bioactive and Compatible Polymers ◽

10.1177/0883911518819224 ◽

2018 ◽

Vol 34 (2) ◽

pp. 209-223

Author(s):

Shideh Shaneh ◽

Fatemeh Shokrolahi ◽

Parvin Shokrollahi ◽

Hamid Yeganeh ◽

Hossein Omidian

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Ethylene Glycol ◽

Structural Engineering ◽

Cell Attachment ◽

Poly Ethylene Glycol ◽

Salt Leaching ◽

The Matrix ◽

Diphenyl Tetrazolium Bromide ◽

Poly Ethylene

Poly(urethane urea) scaffolds were fabricated through combined salt leaching and solvent casting methods. The scaffolds were then functionalized via aminolysis with poly(ethylene glycol) (PEG- g-PUU). To compare its bioactivity, gelatin was also grafted onto the aminolyzed poly(urethane urea) surface (Gel- g-PUU). Chemical changes at the surface were then monitored using quantitative/qualitative methods. Grafting with both gelatin and poly(ethylene glycol) remarkably enhanced the wettability of poly(urethane urea). Proliferation of human adipose–derived mesenchymal stem cells on poly(urethane urea) and the modified poly(urethane urea)s was evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay. The cell experiment results showed that both the modified poly(urethane urea)s enhanced the attachment and proliferation of human adipose–derived mesenchymal stem cells compared to pure poly(urethane urea). Based on previous reports, while a supportive role is observed at adequate poly(ethylene glycol) graft densities, cell adhesion and proliferation are inhibited at very high grafting densities. To correlate the cell data to poly(ethylene glycol) conformations, the surface tension was measured. Data on human adipose–derived mesenchymal stem cells’ attachment/proliferation and contact angle/surface free energy together showed that the grafting density of poly(ethylene glycol) was regulated by optimizing aminolysis conditions, careful selection of poly(ethylene glycol)’s molecular weight, and bulk properties of the matrix poly(urethane urea). As a result, surface overcrowding and brush conformation of the poly(ethylene glycol) chains were avoided, and human adipose–derived mesenchymal stem cell attachment and proliferation occurred on the PEG- g-PUU scaffold at a comparable level to the Gel- g-PUU.

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