Multivalent (Nitrilotriacetic Acid)‐End‐Functionalized Polystyrenes by ATRP and Their Self‐Assembly

Abstract

The synthesis of tri‐(nitrilotriacetic acid) (NTA)‐end‐functionalized polystyrenes using an initiator containing tert‐butyl protected NTA moieties, by atom transfer radical polymerization (ATRP) of styrene is described. First, a suitable ATRP initiator is prepared and subsequently characterized by 1H and 13C NMR spectroscopy, gel‐permeation chromatography (GPC), and matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) mass spectro­scopy. The structures of the tri‐NTA‐end‐functionalized polystyrenes (tri‐NTA‐PS) are confirmed by 1H and 13C NMR spectroscopy. Tri‐NTA‐PS itself produces self‐assembled spherical aggregates with ≈40–60 nm diameters in water/THF, whereas nickel‐complexed tri‐NTA‐PS produces spherical core–shell hybrid aggregates with ≈90–115 nm diameters with His‐tagged GFP in water/DMF (DMF 4 vol%), as confirmed by transmission electron microscopy and dynamic light scattering measurements.

Nitrilotriacetic Amine-Functionalized Polymeric Core–Shell Nanoparticles as Enzyme Immobilization Supports

“…44 The synthesis of the t-butyl protected NTA amine 1 consisted of two steps (Scheme 2). 42 After coupling 1 with NHS-MAMA-SG1 and chromatographic purification, the pNTA-functionalized NMP initiator 2 was obtained as a colorless oil (see Figure S2 for characterization). It was decided to directly employ the protected initiator for polymerization and to hydrolyze the tbutyl esters at a later point, e.g., after synthesis of pNTAfunctionalized macroinitiator or after nanoparticle formation.…”

“…N -hydroxysuccinimide (NHS; 98+%, Acros), oligo­(ethylene glycol) methacrylate M n = 950 (OEGMA 950 ; Sigma-Aldrich), nickel­(II)­sulfate hexahydrate (99%, Acros), 2,2′-azino-bis­(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS; Applichem), p -nitrophenylbutyrate (≥98%, Sigma-Aldrich), ethanol (Fisher), and xylene (Roth) were used as received. N -(2-methyl-2-propyl)- N -(1-diethylphosphono-2,2-dimethylpropyl)- N -oxyl) (SG1; 85%), N -(2-methyl-2-propyl)- N -(1-diethylphosphono-2,2-dimethylpropyl)- O -(2-carboxyprop-2-yl) hydroxylamine (MAMA-SG1; 99%), 2-methyl-2-[ N - tert -butyl- N -(1-diethoxyphosphoryl-2,2-dimethylpropyl)­aminoxy]- N -propionyloxysuccinimde (NHS-MAMA-SG1), 2-methyl-2-[ N - tert -butyl- N -(1-diethoxyphosphoryl-2,2-dimethylpropyl)­aminoxy]- N -hydroxyethyl propionamide (HO-MAMA-SG1), and N α , N α -bis­( tert -butoxycarbonylmethyl)­lysine tert -butylester (pNTA-amine, 1 ) were obtained following literature procedures, which are nevertheless described in the Supporting Information.…”

“…N-hydroxysuccinimide (NHS; 98+%, Acros), oligo(ethylene glycol) methacrylate M n = 950 (OEGMA 950 ; Sigma-Aldrich), nickel-(II)sulfate hexahydrate (99%, Acros), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS; Applichem), p-nitrophenylbutyrate (≥98%, Sigma-Aldrich), ethanol (Fisher), and xylene (Roth) were used as received. N-(2-methyl-2-propyl)-N-(1-diethylphosphono-2,2dimethylpropyl)-N-oxyl) (SG1; 85%), 39 4 1 a n d N α , N α -b i s ( t e r tbutoxycarbonylmethyl)lysine tert-butylester (pNTA-amine, 1) 42 were obtained following literature procedures, which are nevertheless described in the Supporting Information.…”

Morphology Control of Ni(II)-NTA-End-Functionalized Block Copolymer and Bio-Conjugation through Metal-Ligand Complex

“…10 × 10 −6 M), [ 21 ] fast, [ 22 ] selective [ 23 ] and reversible [ 24 ] interaction. Due to these advantages of Ni 2+ -NTA and its mild condition driving high preservation of protein activities for association and dissociation processes, this functional group has been applied for purification [ 25 , 26 , 27 , 28 , 29 ] and detection [ 30 , 31 ], as well as for surface immobilization [ 22 , 32 , 33 , 34 , 35 , 36 ] of multi-His tagged proteins. Especially in the surface immobilization field, attaching His tagged proteins to lipid-based carriers functionalized with Ni 2+ -NTA was reported broadly as a functional and oriented immobilization system [ 24 , 32 , 33 ].…”