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Abstract: A large number of molecularly imprinted polymers (MIPs) have been investigated and reported over the last decade. Various templates have been successfully exploited and used, leading to significant advances in separation, adsorption, catalysis, sensing, and drug delivery. Among all the templates, small molecules have dominated in the synthesis of MIPs. In contrast, progress made in imprinting macromolecules has been slow, mainly due to the challenges presented by the size, structure and conformational fragility of biological macromolecules. In this review, we focus on discussing some key issues involved in the imprinting of macromolecules from recent publications. The similarity and difference between imprinting small molecules and macromolecules are highlighted. Other aspects relating to polymer design and function are also discussed. [Copyright &y& Elsevier]

Abstract: A novel electrochemical immunosensor capable of enzyme-free detection of alpha fetoprotein (AFP) is reported. This immunosensor was fabricated in a sandwich-like format where catalytic Au–Pd nanocrystals and highly conductive N-doped graphene sheets were incorporated. The significant catalysis by Au–Pd nanocrystals toward hydrogen peroxide, along with the increased electron transfer by graphene sheets, caused signal generation and increased sensitivity, which enables the enzyme-free detection of AFP. With a low detection limit at 0.005ngmL−1, this novel immunosensor worked well over the broad linear range of 0.05–30ngmL−1. Unlike previously reported enzyme-based electrochemical immunosensors, which often involve the complicated steps for enzyme loading and necessary treatments to keep the activity of enzyme, this novel immunosensor is simple in nature and employed catalytic Au–Pd nanoparticles and highly conductive graphene, which thus enables reliable and sensitive detection for clinic usage. [Copyright &y& Elsevier]

In this paper, we report a novel three-layer polymer reactor capable of simple/tandem self-controlled catalysis. The top and bottom layers were composed of two different molecularly imprinted polymers respectively containing two catalytic sites (an acidic site catalyzing hydrolysis and metal nanoparticles catalyzing reduction), performing two selective tandem reactions without interference between each other. The middle layer was composed of a copolymer of poly- N -isopropylacrylamide (PNIPAM) and polyacrylamide (PAm) in different ratios, acting as a temperature-responsive switch for the tandem catalysis process. In an aqueous environment, when the temperature is lower than the Lower Critical Solution Temperature (LCST) of the copolymer, the reactor exhibited an open middle access (hydrophilic condition) of intermediate, allowing the tandem processes from hydrolysis to reduction. When the temperature is higher than the LCST, the channels of the middle layer were closed (hydrophobic condition), which obstructed the access of reactants. As a result, the reactor could only conduct simple hydrolysis processes. Therefore, with the three-layer structure, the polymer reactor has led to a self-controlled catalysis. This new multi-layer polymeric reaction concept can expand the practical use of functional catalysts by permitting the control of processes in large temperature ranges. The switchable mechanism of the three-layer polymer reactor. [Display omitted] • A three-layer polymer reactor with non-tandem/tandem self-controlled catalytic abilities was prepared. • The middle layer made of PNIPAM-PAM acts as a molecular switch to control the tandem catalysis. • Tandem catalysis without interference was obtained by using molecularly imprinted polymers as carriers. • A temperature controlled and stable smart tandem catalysis was achieved. [ABSTRACT FROM AUTHOR]

This study is aimed at addressing the present challenges of self-controlled processes in tandem catalysis. Inspired by the opening and closing switchable behaviors of stomata in plant leaves arose by temperature, the objective is met by originally developing a "smart" tandem catalyst capable of crossing-response properties. The catalyst consisted of two unique functional layers where each may self-govern one coupled process. The first layer was fabricated with a negatively-thermosensitive imprinted polymer and encapsulated metal nanoparticles (PDEA- co -PAM/Ag) which were responsible for a catalytic reduction process. The second layer was made of a positively-thermosensitive polymer (PVI- co -PAMPS) with acidic groups, which were capable of a catalytic hydrolysis process. At low temperatures, this catalyst would conduct only catalytic reduction because of the open channel in the first layer. In middle temperatures, the catalyst would run the tandem processes from catalytic reduction to hydrolysis because of the open channels in both the two layers. At higher temperatures, the catalyst only catalyzed hydrolysis because of the closed channel in the first layer. In this way, the smart bi-layer catalyst achieved the single/tandem/single catalysis featured with a dual temperature-responsive switch. The novel protocol not only provides a new solution to complicated catalytic processes but also inspires the further application of smart polymers in a broader spectrum of areas. The switchable mechanism of the polymer reactor. [Display omitted] • Thermo-sensitive tandem catalyst is able to adapt to the changing environment. • A "smart" tandem catalyst is capable of crossing-response properties. • The catalyst is able to conduct the single/tandem/single reactions in different temperatures. • New catalyst shares a promising prospect to the development of one-pot catalytic processes in applications. [ABSTRACT FROM AUTHOR]