Synthesis and characterization of photolabile aminoterpolymers for covalent attachment onto gold substrates

Abstract

Abstract-We present the synthesis and characterization of a family of photolabile co-and terpolymers (acrylate/methacrylate type) suitable for nanotechnology applications. They have been obtained by free radical polymerization of the corresponding monomers: a photosensitive component (nitroveratryl methacrylamide type), which allows the release of amino functionalities after the irradiation with UV light, a dithiol derivative that enables the covalent attachment of these materials onto gold substrates, and methyl methacrylate or styrene acting as a spacer between both functional units, promoting the formation of films with good quality. The polymers have been characterized using techniques as NMR, FTIR, GPC, TGA, DSC and UV spectroscopy. The deprotection of the amino function in the terpolymers by UV irradiation has been proven.

Lipoates as building blocks of sulfur-containing branched macromolecules

“…[21][22][23][24] In addition to its biological role, LpA and its reduced form, the dithiol dihydrolipoic (6,8-dimercaptooctanoic) acid, similar to other disulfides and thiols, have a marked affinity for precious (e.g., Au, Ag, Pd) and nonprecious (e.g., Cr, Co, Ni) metals and metal ions (e.g., Cd 2+ , Zn 2+ ). Because of this property, numerous polymeric materials have been developed that contain pendant lipoate moieties, 25 which have been successfully employed as adhesives for metals used in dentistry 26,27 or stabilizers and/or surface modifiers for the functionalization of metal, often Au, nanoparticles, 28,29 and quantum dots. 30 Polymers with multiple pendant 1,2-dithiolane (including lipoate) groups can be reduced to macromolecular multithiols, which can be further oxidized, or participate in thiol-disulfide interchange with disulfides; both processes have been utilized in the preparation of micelles with disulfide-based crosslinked cores 31 or dynamic, self-healing, gels.…”

Photopatternable Films of Block Copolymers Prepared through Double-Click Reaction

“…A promising approach that was developed in our group includes the preparation of photopatternable polymer films which can covalently be attached to silica or gold surfaces. Via selective UV irradiation of these films, a controlled release of functional groups was accomplished. − The possibility of a subsequent site-specific deposition of charged nanoparticles or biomolecules like DNA and proteins was demonstrated. , …”

“…Compared to the random NVOC-protected amino terpolymers prepared through free radical copolymerization, , the polymer analogous approach described here offers several important advantages. In our previous work, the NVOC groups were introduced via NVOC-containing methacrylate monomers.…”

“…Radical copolymerizations of these monomers led to very limited molar masses due to the fact that the NVOC group acts as a scavenger. Thus, molar masses not higher than 4500 g/mol were obtained . To circumvent this problem, the polymer analogous introduction of NVOC-protected amino groups via click chemistry was studied in our group and was shown to be practicable with random propargyloxystyrene- co -styrene copolymers …”

“…Subsequently, the samples were irradiated through a TEM grid, acting as an optical mask by UV light, in order to attain a laterally patterned release of amino groups. The NVOC-protecting groups can be cleaved off by UV light of about 350 nm. , Next, the samples were carefully washed to remove the cleavage products and immersed into a solution of fluoresceine isothiocyanate (FITC) for 1−2 h followed by a thorough washing step. This fluorescent marker molecule is used as a model compound for the often used attachment of biomacromolecules onto amino-functionalized surfaces through isothiocyanate linkers.…”