Tobacco mosaic virus (TMV) is a robust nanotubular nucleoprotein scaffold increasingly employed for the high density presentation of functional molecules such as peptides, fluorescent dyes, and antibodies. We report on its use as advantageous carrier for sensor enzymes. A TMV mutant with a cysteine residue exposed on every coat protein (CP) subunit (TMVCys) enabled the coupling of bifunctional maleimide-polyethylene glycol (PEG)-biotin linkers (TMVCys/Bio). Its surface was equipped with two streptavidin [SA]-conjugated enzymes: glucose oxidase ([SA]-GOx) and horseradish peroxidase ([SA]-HRP). At least 50% of the CPs were decorated with a linker molecule, and all thereof with active enzymes. Upon use as adapter scaffolds in conventional “high-binding” microtiter plates, TMV sticks allowed the immobilization of up to 45-fold higher catalytic activities than control samples with the same input of enzymes. Moreover, they increased storage stability and reusability in relation to enzymes applied directly to microtiter plate wells. The functionalized TMV adsorbed to solid supports showed a homogeneous distribution of the conjugated enzymes and structural integrity of the nanorods upon transmission electron and atomic force microscopy. The high surface-increase and steric accessibility of the viral scaffolds in combination with the biochemical environment provided by the plant viral coat may explain the beneficial effects. TMV can, thus, serve as a favorable multivalent nanoscale platform for the ordered presentation of bioactive proteins.

We present a new ambient temperature synthetic approach for the preparation of single-chain polymeric nanoparticles (SCNPs) under mild conditions using a UV-light-triggered Diels–Alder (DA) reaction for the intramolecular cross-linking of single polymer chains. Well-defined random copolymers with varying contents of styrene (S) and 4-chloromethylstyrene (CMS) were synthesized employing a nitroxide-mediated radical polymerization (NMP) initiator functionalized with a terminal alkyne moiety. Postpolymerization modification with 4-hydroxy-2,5-dimethylbenzophenone (DMBP) and an N-maleimide (Mal) derivative led to the functional linear precursor copolymers. The intramolecular cross-linking was performed by activating the DMBP groups via irradiation with UV light of 320 nm for 30 min in diluted solution (c Polymer = 0.017 mg mL–1). The ensuing DA reaction between the activated DMBP and the Mal groups resulted in well-defined single-chain polymeric nanoparticles. To control the size of the SCNPs, random copolymers with varying CMS contents (i.e., different functional group densities (FGD)) were employed for the single-chain collapse. Additionally, monotethered nanoparticles were prepared via the copper-catalyzed azide–alkyne cycloaddition between the alkyne bearing copolymer with the highest FGD and an azide-terminated poly(ethylene glycol) (PEG) prior to UV-induced cross-linking. The formation of SCNPs was followed by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM).

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We report the precision single-chain folding of narrow dispersity diblock copolymers via pairwise orthogonal multiple hydrogen bonding motifs and single chain selected point folding. Well-defined linear polystyrene (PS) and poly(n-butyl acrylate) (PnBA) carrying complementary recognition units have been synthesized via activators regenerated by electron transfer/atom transfer radical polymerization (ARGET ATRP) utilizing functional initiators yielding molecular weights of M n,SEC = 10900 Da, Đ = 1.09 and M n,SEC = 3900 Da, Đ = 1.10, respectively. The orthogonal hydrogen bonding recognition motifs were incorporated into the polymer chain ends of the respective building blocks (to yield an eight shaped single chain folded polymers). Diblock copolymer formation was achieved via the Cu(I) catalyzed azide–alkyne cycloaddition (CuAAC) reaction, while the single-chain folding of the prepared linear diblock copolymer–at low concentrations–was driven by orthogonal multiple hydrogen bonds via three-point thymine–diaminopyridine and six-point cyanuric acid–Hamilton wedge self-association. The self-folding process was followed by proton nuclear magnetic resonance (1H NMR) spectroscopy focused on the respective recognition pairs at low temperature. In addition, the single-chain folding of the diblock copolymer was analyzed by dynamic light scattering (DLS) and concentration dependent diffusion ordered NMR spectroscopy (DOSY) as well as atomic force microscopy (AFM), providing a limiting concentration for self-folding (in dichloromethane at ambient temperature) of close to 10 mg mL–1.

Conjugated microporous polymers (CMPs) have attracted much interest due to their intrinsic porosity, outstanding stability, and high variability. However, the processing of these materials for membrane application has been limited due to their insoluble nature when synthesized as bulk material. Here we report the synthesis of freestanding CMP-nanomembranes via layer-by-layer growth of a "click" based conjugated microporous polymer on a sacrificial substrate. After dissolution of the substrate the CMPnanomembrane can be transferred to porous substrates and continuously cover holes of up to 50 μm diameter. The CMPnanomembranes appear defect-free as inferred from high selectivity values obtained from gas permeation experiments and from electrochemical investigation in the presence of ferrocene. The presented synthesis method represents a versatile strategy to incorporate CMP materials in functional devices for membrane separation, catalysis, or organic electronics. C onjugated microporous polymers (CMP) are a class of microporous solids which have recently attracted wide interest due to their large surface areas, low densities, and the possibility to incorporate different kinds of functional groups in a modular fashion. 1 In contrast to related metal organic frameworks (MOF) 2−5 or covalent organic frameworks (COF) 6,7 which are formed through reversible reactions, CMPs are formed through high yielding irreversible reactions of rigid building blocks. The resulting CMP materials are amorphous and at the same time often show narrow pore size distribution. 8 The exceptional thermal and chemical stability goes well beyond that of MOFs and COFs and makes this class of porous materials particularly appealing for practical applications such as gas storage, catalysis, and molecular separation. 9,10 Among the numerous synthetic routes used in the past, click reaction chemistry has played a special role as a result of its ease of operation. The high purity and readily accessible products of click chemistry are particularly attractive to produce CMP materials. 11 Among the large variety of CMP applications, two-dimensional nanomembranes with a thickness below 10 nm exhibiting tunable pore sizes that can act as molecular sieves have a particularly large potential, since they are predicted to be ideal separation membranes with many advantages over bulk membranes. 12,13 However, the inert nature of most CMP materials causes severe, intrinsic challenges in their processing to yield large scale membranes. Indeed, only branched "soluble conjugated microporous polymers" (SCMPs) 14 and linear conjugated polymers of intrinsic microporosity (C-PIMs) 15 can be processed from solution. Usually CMPs are, in contrast to most polymers, not soluble in organic solvents, 1 and as a result, common processing techniques to fabricate polymer films from a solution such as spin coating cannot be applied.Considering the recent success in using layer-by-layer or quasi-epitaxial approaches for the fabrication of thin MOFlayers (SURMOFs) 16,17 we fabric...