A carbene insertion approach to functionalised poly(ethylene oxide)-based gels

Functionalization of the PEG Corona of Nanoparticles by Clip Photochemistry in Water: Application to the Grafting of RGD Ligands on PEGylated USPIO Imaging Agent

“…Beside the photoaffinity labeling (PAL) of biological targets, 15,16 the direct photochemical functionalization of polymers (PEGs) in solution has been described, with moderate success. 17,18 One way to avoid a loss of reactivity in liquid phase is to design orthogonal photoconjugation processes based on the recent development of the "photo-click reactions". The BarnerKowollik's group has done pioneering works in this domain with photo-triggered Diels-Alder reactions 19 or nitrile imine-mediated tetrazole-ene cycloadditions (NITEC).…”

Chemical modification of materials by reaction with diaryl diazomethanes

“…7 The method relies upon the generation of carbenes by thermolytic or photolytic methods and their irreversible attachment by insertion into available surface chemical groups; a similar approach has recently been reported by Hayes. [8][9][10] Significantly, this approach permits the possibility of a post-polymerisation step for control of surface properties, but without changing the bulk characteristics of the underlying substrate, and since the applicable substrates may be both organic and inorganic polymers and materials, it is potentially very wide in scope. We have not as yet examined in detail the nature of the surface modification, and report here a study of several substrate types, which have been modified by the introduction of carboxylate, amine and alkyl substituents, using combustion analysis, attenuated total reflection (ATR) IR, reflectance UV and X-ray photoelectron spectroscopy (XPS), giving some direct information concerning the chemical and physical nature of the modified substrates.…”

Synthesis and Application of New Photocrosslinkers for Poly(ethylene glycol)

“…Therefore, it was not possible to characterize this precipitate in more detail by solution techniques. Indeed, Blencowe et al [17] also obtained insoluble crosslinked PEGs by using bis-diazirines as photocrosslinkers. The swelling properties of their crosslinked PEGs were measured in a wide range of solvents including water, dimethylformamide and tetrahydrofuran.…”

“…[13][14][15] Nevertheless, few examples of photoreactions performed in bulk have been described [16] and only one publication reports the use of a bis-diazirine reagent as a photocrosslinker for PEG. [17] In this paper, we describe the synthesis of original bisarylazides and bis-diazirines as potential crosslinking agents of polymers under mild conditions. Their reaction with PEG was studied in bulk and in solution, with the aim of forming defined, soluble, branched PEGs under light activation.…”