Polypeptide Polymer Brushes by Light‐Induced Surface Polymerization of Amino Acid N‐Carboxyanhydrides

Abstract

Silicon wafers are decorated with photoamine generator 4,5-dimethoxy-2-nitrobenzyl 3-(triethoxysilyl)propyl carbamate. UV-irradiation in the presence of benzyl-l-glutamate N-carboxyanhydride is carried out, resulting in the release of the surface-bound primary amines, making them viable N-carboxyanhydride (NCA) polymerization initiators. Successful polypeptide grafting is confirmed by water contact angle measurements as well as by ellipsometry, revealing a poly(benzyl-l-glutamate) (PBLG) layer of ≈3 nm. X-ray photoelectron spectroscopy confirms the presence of amide groups in the grafted PBLG while time-of-flight secondary ion mass spectroscopy provides additional evidence for the presence of PBLG on the surface. Evaluation of negative control samples confirms successful UV surface grafting. The approach is thus established as a viable general method for light exposure directable polypeptide functionalization of silicon surfaces.

Photoinduced ring-opening polymerizations

“…A under UV irradiation is composed of neutral compounds featuring a carbamate photocleavable linkage (Scheme 6) [40][41][42][43][44]. Upon photo-decarboXylation, they allow the generation of primary or secondary amines, which has proven to be particularly useful to trigger the ROP of NCAs (see Section 3.3).…”

“…carbonates [41,48,52,[126][127][128][129][130]134,136] as well as NCAs [42][43][44]160,161]. The photopolymerization of cyclo-olefins, which has also been and is still the subject of an intense research, is also discussed [28].…”

“…In another contribution, Stukenkemper et al applied the same concept for the surface functionalization of silicon wafers [44]. Here, introduction of primary amines onto the silicon surface was achieved through the design of a silane based photoamine generator PBG3 (Scheme 55).…”

“…O-carboXyanhydrides are a family of cyclic monomers leading to poly(α-hydroXy acid)s by ROP [223]. These polymers exhibit interesting (BLG = benzyl L-glutamate) [44]. useful in the field of biomaterials.…”

Maskless, Reusable Visible-Light Direct-Write Stamp for Microscale Surface Patterning

“…Residues of such chemical waste might be detrimental to biological applications. Indeed, most photocages for amino group protection contain nitroaromatic − or coumarin derivatives, both having high intrinsic toxicity. In addition, photocaged SAM would be difficult to handle and would have a limited shelf-life because of its light sensitivity.…”