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Artificial enzymes, usually created by incorporating one or two abiological catalytic species into protein hosts, are becoming promising tools for biocatalysis. However, they are still far behind natural enzymes due to their limited active sites with low activity and selectivity. Here, we proposed a polymeric approach to generate artificial enzymes by combining proteins with organocatalytic polymers, in which multiple proline organocatalysts are grafted from protein scaffolds via atom-transfer radical polymerization. The resultant artificial polyenzymes, abbreviated as "ArPoly", have similar physicochemical properties as natural enzymes and proved to be effective aldolase mimics for the aqueous asymmetric aldol reaction, in which an optimal ArPoly gave rise to 33% conversion and 94% enantioselectivity. Therefore, we proved the concept of water-soluble proline-based organocatalyst for aqueous asymmetric aldol reactions. This success not only expands the toolbox of asymmetric organocatalysis but also opens other avenues in the field of artificial enzymes where a plethora of proteins/enzymes can be combined with various well-designed organocatalytic polymers for synthetically useful reactions.

Proline-catalyzed aldol reactions have been developed as an important toolbox for the synthesis of valuable chiral intermediates, giving birth to asymmetric organocatalysis. Despite progress, their current applications are generally performed in highly polar solvents that are either difficult to remove or with low substrate/product solubility. In addition, prolines are often used as homogeneous organocatalysts in these solvents, thus, the recycling of catalyst for reuse is also challenging. To solve these problems, we develop a proline-based Pickering emulsion for asymmetric aldol reactions with high reactivity and selectivity. The emulsion was stabilized by proline-functionalized silica nanoparticles that are not only highly active in the presence of water but also easily recycled after the operation. Interestingly, their high stereoselectivity was not compromised after multiple reuse, i.e., >86 ee (enantiomeric excess) in the first and second use. With this demonstration, we prove the concept that efficient and selective aldol reactions are enabled by proline-based Pickering emulsions, which is a great and continuous contribution to the field of asymmetric organocatalysis.

Ruthenium (Ru)-based catalysts have displayed compelling hydrogen evolution activities, which hold the promising potential to substitute platinum in alkaline H

Fatty acid-derived products such as alkanes, fatty aldehydes, and fatty alcohols have many applications in the chemical industry. These products are predominately produced from fossil resources, but their production processes are often not environmentally friendly. While microbes like

Biocatalysis is increasingly being explored for the sustainable development of green industry. Though enzymes show great industrial potential with their high efficiency, specificity, and selectivity, they suffer from poor usability and stability under abiological conditions. To solve these problems, researchers have fabricated nano- and micro-sized biocatalytic reactors based on the self-assembly of various polymers, leading to highly stable, functional, and reusable biocatalytic systems. This Review highlights recent progress in self-assembled polymeric nano- and microreactors for biocatalytic synthesis, including polymersomes, reverse micelles, polymer emulsions, Pickering emulsions, and static emulsions. We categorize these reactors into monophasic and biphasic systems and discuss their structural characteristics and latest successes with representative examples. We also consider the challenges and potential solutions associated with the future development of this field.

Artificial polyenzymes (ArPoly) are tailored combinations of universal protein scaffolds and polymers newly proposed as promising alternatives to natural enzymes to expand the biocatalyst toolbox. The concept of ArPoly has been continuously extended to metal-containing ArPoly to overcome the drawbacks faced by conventional artificial metalloenzymes. Herein, we present a sustainable route to synthesize a novel water-soluble metalloenzyme for copper-catalyzed azide-alkyne cycloadditions in water with remarkable selectivity. In this case, synthetic l-proline monomers were polymerized onto bovine serum albumen in an aqueous medium via copper-mediated "grafting-from" atom-transfer radical polymerization, resulting in protein-polymer-copper conjugates named ArPoly

Nonaqueous Pickering emulsions (PEs) are a powerful platform for catalysis design, offering both a large interface contact and a preferable environment for water-sensitive synthesis. However, up to now, little progress has been made to incorporate insoluble enzymes into the nonaqueous system for biotransformation. Herein, we present biocatalytically active nonaqueous PEs, stabilized by particle-enzyme nanoconjugates, for the fast transesterification and esterification, and eventually for biodiesel synthesis. Our nanoconjugates are the hybrid biocatalysts tailor-made by loading hydrophilic Candida antarctica lipase B onto hydrophobic silica nanoparticles, resulting in not only catalytically active but highly amphiphilic particles for stabilization of a methanol-decane emulsion. The enzyme activity in these PEs is significantly enhanced, ca. 375-time higher than in the nonaqueous biphasic control. Moreover, the PEs can be multiply reused without significant loss of enzyme performance. With this proof‐of‐concept, we reasonably expect that our system can be expanded for many advanced syntheses using different enzymes in the future.

Biocatalytic cascade reactions have become increasingly important and useful for chemical synthesis. However, biocatalysts are often incompatible with organic solvents, which prohibits many cascade reactions involving nonpolar substrates. In this work, we used cell-free protein synthesis (CFPS) to express enzymes in an aqueous-organic biphasic system for the construction of an artificial enzymatic pathway. CFPS-expressed enzymes without purification performed efficiently to convert styrene (below 20 mM) to (S)-1-phenyl-1,2-ethanediol (two steps in one pot) with 100% conversion. In addition, our CFPS system showed great tolerance to different organic solvents and, importantly, the entire biocatalytic system can be consistently scaled up without reduction of the substrate conversion rate. We therefore anticipate that our cell-free approach will make possible cost-effective, high-yielding synthesis of valuable chemicals.

Objective: Lipoprotein-associated phospholipase A2 (LP-PLA2) is closely related to the development of atherosclerosis. The A379V gene polymorphism, located in exon 11 of the PLA2G7 gene, can affect...

Protein-polymer conjugates have been widely fabricated and used in many areas across biotechnology and medicine. However, their functions and applications are often limited due to the selected and unchangeable proteins and polymers in the conjugates. To address this constraint, here, we design and fabricate protein-polymer conjugates as generic materials that can be postfunctionalized in a plug-and-play means for tunable catalysis. The key idea is to use genetically encoded "click"chemistry (i.e., SpyTag/SpyCatcher) to functionalize premade conjugates with versatile catalytic moieties. This process can protect the function/activity of ligated moieties from exposure to harsh chemical reactions. To enable easy recyclability, the conjugates are encapsulated in hydrogels before the "click"reaction. Using a biocatalyst and a nanocatalyst as models, we demonstrate the success of using two functionalized hydrogels for efficient catalytic reactions. In addition, the two catalysts can be coupled to perform a two-step artificial chemoenzymatic cascade reaction. Notably, the hydrogel-based catalytic materials allow for easy recovery and reuse for multiple cycles. We anticipate that our strategy will help create easy-to-use materials for catalysis and chemical (bio)transformations.

The compartmentalization of chemo- and enzymatic reactions is an elegant strategy for one-pot synthesis while avoiding reaction incompatibility issues. However, chemoenzymatic compartments developed to date are limited to complicated preparation. Herein, a simple, catalytically active polymer that stabilizes diverse types of emulsions for the encapsulation of active enzymes is presented. This design combines two distinct catalysts for cascade reaction while creating separate micro-environments with a large interfacial area for high reactivity. Moreover, the system is developed for solvent-free reactions, benefiting the “green” synthesis.

Multienzyme cascade biocatalysis is an efficient synthetic process, avoiding the isolation/purification of intermediates and shifting the reaction equilibrium to the product side.. However, multienzyme systems are often limited by their incompatibility and cross‐reactivity. Herein, we report a multi‐responsive emulsion to proceed multienzyme reactions sequentially for high reactivity. The emulsion is achieved using a CO2, pH, and thermo‐responsive block copolymer as a stabilizer, allowing the on‐demand control of emulsion morphology and phase composition. Applying this system to a three‐step cascade reaction enables the individual optimal condition for each enzyme, and a high overall conversion (ca. 97 % of the calculated limit) is thereby obtained. Moreover, the multi‐responsiveness of the emulsion allows the facile and separate yielding/recycling of products, polymers and active enzymes. Besides, the system could be scaled up with a good yield., A CO2, pH, and thermo‐responsive emulsion was developed to perform multienzyme cascades without incompatibility and cross‐reactivity issues. This emulsion allows the on‐demand control of morphology and phase composition, and therefore exchanging enzymes and separate yielding/recycling of products and polymers. A three‐enzyme cascade was performed sequentially, each step was carried out under the optimal conditions of the corresponding enzyme.

In cooperative catalysis, the combination of chemo- and biocatalysts to perform one-pot reactions is a powerful tool for the improvement of chemical synthesis. Herein, UiO-66-NH2 was employed to stepwise immobilize Pd nanoparticles (NPs) and Candida antarctica lipase B (CalB) for the fabrication of biohybrid catalysts for cascade reactions. Distinct from traditional materials, UiO-66-NH2 has a robust but tunable structure that can be utilized with a ligand exchange approach to adjust its hydrophobicity, resulting in excellent catalyst dispersity in diverse reaction media. These attractive properties contribute to the formation of MOF-based biohybrid catalysts with high activity and selectivity in the synthesis of benzyl hexanoate from benzaldehyde and ethyl hexanoate. With this proof-of-concept, we reasonably expect that future tailor-made MOFs can combine other catalysts, ranging from chemical to biological catalysts for applications in industry.

The combination of chemo- and biocatalysts offers a powerful platform to address synthetic challenges in chemistry, particularly in synthetic cascades. However, transferring both catalysts into organic solvents remains technically difficult because of the enzyme inactivation and catalyst precipitation. Herein, we designed a facile approach using functionalized mesoporous silica nanoparticles (MSN) to transfer chemo- and biocatalysts into a variety of organic solvents. As a proof-of-concept, two distinct catalysts, palladium nanoparticles (Pd NPs) and Candida antarctica lipase B (CalB), were stepwise loaded into separate locations of the mesoporous structure, which not only provided catalysts with heterogeneous supports for the recycling but also avoided their mutual inactivation. Moreover, mesoporous particles were hydrophobized by surface alkylation, resulting in a tailor-made particle hydrophobicity, which allowed bifunctional catalysts to be dispersed in eight organic solvents. Eventually, these attractive material properties provided the MSN-based bifunctional catalysts with remarkable catalytic performance for cascade reaction synthesizing benzyl hexanoate in toluene. With a broader perspective, the success of this study opens new avenues in the field of multifunctional catalysts where a plethora of other chemo- and biocatalysts can be incorporated into surface-functionalized materials ranging from soft matters to porous networks for synthetic purposes in organic solvents.

The design and construction of polymeric compartmentalized structures in water have been intensively explored for controllable catalysis, but there is still the challenge of setting up catalytic compartments in organic media. Here, we designed a simple block copolymer, PCL-b-PEG-b-PCL, to construct a stable and multi-compartmentalized emulsion in an organic solvent by hand-shaking. This gentle emulsion preparation allowed a successful encapsulation of vulnerable biocatalysts such as benzaldehyde lyase (BAL) and alcohol dehydrogenase (ADH). The compartmentalization provided the emulsion with an exceptionally large interfacial area that could enhance BAL activity up to 225 times as compared to the traditional biphasic system. Moreover, the system could be easily scaled up due to its facile preparation with low cost. Therefore, our results pave the way for developing compartmentalized structures in solvents for biocatalysis in large-scale synthetic chemistry.

For designing water-soluble responsive materials, utilizing crown ethers as main building blocks has been rarely explored in contrast to their linear poly(ethylene glycol) counterparts. In the current study, we report the robust thermoresponsive properties of the benzo-21-crown-7 (B21C7) family with lower critical solution temperature (LCST) and upper critical solution temperature (UCST) behavior. Different substituent groups on the benzene ring exhibit significant effects on water solubility and thermoresponsiveness. B21C7 and its cyano derivative display LCST phenomena, while B21C7-based carboxylic acid derivative presents UCST followed by LCST phase behavior. Supramolecular interactions with KCl provide an additional tuning approach for this crown ether system. These results demonstrate that B21C7s can serve as an easily accessible toolbox to develop new thermosensitive systems and prepare thermally responsive materials.

In the past decades, advances in nanoparticles (NPs) synthesis and engineering have greatly propelled the application of nanoscale agents for therapeutic and diagnostic functions, promoting an emerging field of "nanotheranostics". In particular, they are being increasingly exploited for cancer management, in which diagnosis and therapy are combined to address clinical challenges. In this work, core-shell-structured amorphous zinc oxide (a-ZnO) on gold NPs (Au-His@a-ZnO) was produced using histidine (His) to control the shell growth under hydrothermal conditions. Subsequently, Au-His@a-ZnO NPs were integrated onto the planar structure of PEGylated graphene oxide (PEG-GO) via carbodiimide cross-linker chemistry. More importantly, strong absorption and near-infrared (NIR) emission in the range of 700 to 900 nm was observed with preferential uptake at tumors and high photothermal conversion efficiency (η = 38%). Both in vitro and in vivo studies showed that the GO@Au-His@a-ZnO NCs were biocompatible with low toxicity. Moreover, GO@Au-His@a-ZnO NCs were further conjugated with the antibody of epidermal growth factor receptor aptamer (anti-EGFR Apt) and doxorubicin (DOX), yielding Apt@GO@Au-His@a-ZnO@DOX NCs, which were then applied toward the synergetic treatment of lung cancer. The prepared Apt@GO@Au-His@a-ZnO@DOX NCs showed a high loading capacity of DOX, as well as NIR/pH-sensitive drug release in which the metal-drug complex dissociated to release antitumor Zn 2+ ions into the acidic endosome/lysosome. In addition, these materials also showed good biostability and anti-EGFR Apt-promoted binding specificity for lung cancer cells. The specific binding facilitated the cellular uptake into EGFR-mutated cancer sites, as compared with nontargeted controls. In particular, human pulmonary adenocarcinoma cell (A549)-tumor bearing mice were selected as the animal model, and efficient targeted drug delivery and the high anticancer efficacy of Apt@GO@Au-His@a-ZnO NCs in vivo were demonstrated. Taken together, our multifunctional NCs, Apt@GO@Au-His@a-ZnO@DOX NCs, have shown high efficacy in targeted, photothermal, and chemotherapy when applied to lung cancer. This proof-of-principle example suggests a fascinating perspective for these functional NCs for future clinical use.

Prevention of microbial contamination of surfaces is one of the biggest challenges for biomedical applications. Establishing a stable, easily produced, highly antibacterial surface coating offers an efficient solution but remains a technical difficulty. Here, we report on a new approach to create an in situ hydrogel film-coating on glass surfaces made by enzymatic cross-linking under physiological conditions. The cross-linking is catalyzed by horseradish peroxidase (HRP)/glucose oxidase (GOD)-coupled cascade reactions in the presence of glucose and results in 3D dendritic polyglycerol (dPG) scaffolds bound to the surface of glass. These scaffolds continuously release H2O2 as long as glucose is present in the system. The resultant polymeric coating is highly stable, bacterial-repellent, and functions under physiological conditions. Challenged with high loads of bacteria (OD540 = 1.0), this novel hydrogel and glucose-amended coating reduced the cell viability of Pseudomonas putida (Gram-negative) by 100% an...

Considering the critical role of mitochondria in the life and death of cells, non-invasive long-term tracking of mitochondria has attracted considerable interest. However, a high-performance mitochondria-specific labeling probe with high photostability is still lacking. Herein a highly photostable hyperbranched polyglycerol (hPG)-based near-infrared (NIR) quantum dots (QDs) nanoplatform is reported for mitochondria-specific cell imaging. Comprising NIR Zn-Cu-In-S/ZnS QDs as extremely photostable fluorescent labels and alkyl chain (C12 )/triphenylphosphonium (TPP)-functionalized hPG derivatives as protective shell, the tailored QDs@hPG-C12 /TPP nanoprobe with a hydrodynamic diameter of about 65 nm exhibits NIR fluorescence, excellent biocompatibility, good stability, and mitochondria-targeted ability. Cell uptake experiments demonstrate that QDs@hPG-C12 /TPP displays a significantly enhanced uptake in HeLa cells compared to nontargeted QDs@hPG-C12 . Further co-localization study indicates that the probe selectively targets mitochondria. Importantly, compared with commercial deep-red mitochondria dyes, QDs@hPG-C12 /TPP possesses superior photostability under continuous laser irradiation, indicating great potential for long-term mitochondria labeling and tracking. Moreover, drug-loaded QDs@hPG-C12 /TPP display an enhanced tumor cell killing efficacy compared to nontargeted drugs. This work could open the door to the construction of organelle-targeted multifunctional nanoplatforms for precise diagnosis and high-efficient tumor therapy.

Despite the rapid development of Pickering interfacial catalysis (PIC) at liquid-liquid interfaces with chemocatalysts, the use of unstable biocatalysts at emulsion interfaces remains a technical challenge. Herein, we present a Pickering interfacial biocatalysis (PIB) platform based on robust and recyclable enzyme-polymer conjugates that act as both catalytic sites and stabilizers at the interface of Pickering emulsions. The conjugates were prepared by growing poly(N‐isopropylacrylamide) on a fragile enzyme, benzaldehyde lyase, under physiological conditions. The mild in situ conjugation process preserved the enzyme structure, and the conjugates were used to emulsify a water-organic two‐phase system into a stable Pickering emulsion, leading to a significantly larger interfacial area and a 270‐fold improvement in catalytic performance as compared to the unemulsified two‐phase system. The PIB system could be reused multiple times. Conjugates of other enzymes were also fabricated and applied for cascade reactions.

Combination therapies for tumors based on different therapeutic approaches should try to improve treatment efficacy, but also to reduce side-effects related to the exogenous stimulus and premature release. In the following study, we established and validated a pH/near-infrared (NIR)/glutathione (GSH)/-responsive multifunctional disulfide cross-linked Fe

Whole-cell biocatalysis plays an important role in biotransformation with unique features such as good tolerance of solvents and easy recycling. However, the relatively low catalytic efficiency limits their use in real production. In this study, a multi-compartmentalized emulsion in organic solvent was constructed to encapsulate living cells for enhanced catalytic performance. Extraordinary large interfacial area of the emulsion improved the bioactivity of Escherichia coli (E. Coli) cells up to 137 times compared to a standard biphasic system. The emulsion was stabilized by a biocompatible polymer and prepared by gentle shaking by hand, which resulted in good cell viability. Moreover, the encapsulated cells could be easily recycled, and the activity remained more than 70% after five cycles. This work provides a promising approach for utilizing whole-cell catalysts for efficient organic catalysis.

The immobilization of lipase B from Candida antarctica (CalB) within micronsized poly-N-Isopropylacrylamide (p-NIPAM) microgel particles with a crosslinker content of 5% is reported. The immobilization of the enzyme was reached by an exchange from polar to organic solvents. After determining the embedded amount of CalB within the polymer network, an enhanced specific activity in n-hexane was obtained. Due to the thermoresponsibility of the polymer particles, the activity reaction was done at 25 ºC and 50 ºC. The results presented show that the reversible collapse of the microgel leads to a decreased activity with increasing temperature. Hence, p-NIPAM microgels display a good opportunity to tailor the activity of CalB. An interesting side effect is that CalB presents a suitable probe to estimate the mesh size of the polymer network, since it penetrates in the unlabeled form but not after labeling with FITC.

The exploration of effective platforms for immobilizing chemo- and biocatalysts to develop biohybrid catalysts is an attractive subject of practical interest. In this work, carbon nitride (C3N4) is used for the first time as a platform for the immobilization of metal catalyst (Pd nanoparticles) and biocatalyst (Candida antarctica lipase B, CalB) in a facile manner to prepare biohybrid catalyst. The optimal biohybrid catalyst inherits the intrinsic performance of both Pd nanoparticles and CalB, and shows high activity in the one-pot cascade reaction converting benzaldehyde to benzyl hexanoate at room temperature. With this proof of concept, it is expected that C3N4 can be utilized for immobilizing more types of chemo- and biocatalysts for perspective applications.

Thermophilic bacterial strains HEN-Qn1 were incubated at 60 °C in a solution containing calcium chloride. With slow release of CO2 metabolic end products from the bacteria, CaCO3 nanomaterials were found after 12 h through a transmission electron microscope (TEM). CaCO3 nanorods were obtained extracellularly, whereas a unique morphology of nanosphere was observed intracelluarly. A single crystal was further characterized by electron pattern (ED) and X-ray powder diffraction (XRD). Moreover, a putative mechanism has been proposed based on theoretical analyses and experimental evidences. These results indicated that thermophilic bacteria had a well-controlled effect during the crystal growth of inorganic materials, which provided us a promising application of bacteria in biosynthesis of nanomaterials.

Nanoparticle metal oxides are emerging as a new class of important materials in medical, agricultural, and industrial applications. In this context, free zinc oxide (ZnO) nanoparticles (NPs) have been increasingly shown with broad antimicrobial activities. However, biological properties of immobilized ZnO NPs on matrixes like nanofibrous membranes are still limited. In this study, in situ synthesized ZnO NPs/polyvinyl alcohol (PVA) nanofibrous membranes were fabricated by electrospinning with different zinc acetate concentrations. Characterization results indicated that, with 5 mM zinc acetate, uniform size ZnO NPs (~40 nm) were formed and evenly distributed on the membrane surface. The surfaces became more hydrophobic with higher concentration of zinc acetate. ZnO NPs/PVA nanofibrous membranes showed a broad spectrum of antimicrobial activities and cell adhesion inhibiting effects against four microorganisms including Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, fungi Candida albicans, and spores of Aspergillus niger. Our data revealed that the major antimicrobial mechanism could be attributed to cell membrane damage and cellular internalization of ZnO NPs, while the hydrophobic surface of the membrane primarily contributed to the cell adhesion inhibition. This study suggests that ZnO NPs/PVA nanofibrous membranes could potentially be used as an effective antimicrobial agent to maintain agricultural and food safety.

The bactericidal action of silver (0) nanoparticles and amoxicillin on Escherichia coli is studied, respectively. Increasing concentration of both amoxicillin (0–0.525 mg ml−1) and silver nanoparticles (0–40 µg ml−1) showed a higher antibacterial effect in Luria–Bertani (LB) medium. Escherichia coli cells have different bactericidal sensitivity to them. When amoxicillin and silver nanoparticles are combined, it results in greater bactericidal efficiency on Escherichia coli cells than when they were applied separately. Dynamic tests on bacterial growth indicated that exponential and stationary phases are greatly decreased and delayed in the synergistic effect of amoxicillin and silver nanoparticles. In addition, the effect induced by a preincubation with silver nanoparticles is examined. The results show that solutions with more silver nanoparticles have better antimicrobial effects. One hypothesized mechanism is proposed to explain this phenomenon.

The enormous potential of nanogel scaffolds for protein encapsulation has been widely recognized. However, constructing stable polymeric nanoscale networks in a facile, mild, and controllable fashion still remains a technical challenge. Here, we present a novel nanogel formation strategy using horseradish peroxidase (HRP) catalyzed crosslinking on phenolic derivatized dendritic polyglycerol (dPG) in the presence of H2O2 in an inverse miniemulsion. This "enzymatic nanogelation" approach was efficient to produce stable 200 nm dPG nanogel particles, and was performed under physiological conditions, thus making it particularly beneficial for encapsulating biological proteins. Purification of the nanogels was easy to handle and practical because there was no need for a post-quenching step. Interestingly, the use of dPG resulted in higher HRP laden nanogels than for linear polyethylene glycol (PEG) analogs, which illustrates the benefits of dendritic backbones in nanogels for protein encapsulation. In addition, the mild immobilization contributed to the enhanced thermal stability and reusability of HRP. The nanogel preparation could be easily optimized to achieve the best HRP activity. Furthermore, a second enzyme, Candida antarctica lipase B (CalB), was successfully encapsulated and optimized for activity in dPG nanogels by the same enzymatic methodology, which shows the perspective applications of such techniques for encapsulation of diverse proteins.

Although several strategies are now available to enzymatically cross-link linear polymers to hydrogels for biomedical use, little progress has been reported on the use of dendritic polymers for the same purpose. Herein, we demonstrate that horseradish peroxidase (HRP) successfully catalyzes the oxidative cross-linking of a hyperbranched polyglycerol (hPG) functionalized with phenol groups to hydrogels. The tunable cross-linking results in adjustable hydrogel properties. Because the obtained materials are cytocompatible, they have great potential for encapsulating living cells for regenerative therapy. The gel formation can be triggered by glucose and controlled well under various environmental conditions.

A new and versatile, crown ether appended, chiral supergelator has been designed and synthesized based on the bis-urea motif. The introduction of a stereogenic center improved its gelation ability significantly relative to its achiral analogue. This low-molecular-weight gelator forms supramolecular gels in a variety of organic solvents. It is sensitive to multiple chemical stimuli and the sol-gel phase transitions can be reversibly triggered by host-guest interactions. The gel can be used to trap enzymes and release them on demand by chemical stimuli. It stabilizes the microparticles in Pickering emulsions so that enzyme-catalyzed organic reactions can take place in the polar phase inside the microparticles, the organic reactants diffusing through the biphasic interface from the surrounding organic phase. Because of the higher interface area between the organic and polar phases, enzyme activity is enhanced in comparison with simple biphasic systems.

Encapsulation of enzymes in Pickering emulsions results in a large interfacial area of the enzyme-containing aqueous phase for biocatalysis in organic media. This immobilization technique minimizes enzyme inactivation through stabilizing immiscible liquids by particles, facilitates separation processes, and significantly increases catalytic performance of both stable and vulnerable enzymes. Thus, a broad technical applicability can be envisioned Refereed/Peer-reviewed

When computing optical flow with region-based matching, very few of them can be reliably obtained, especially for the high-contrast areas or those with little texture. Instead of using a single pixel from the reference frame, non-deterministic motion utilizes multiple pixels within a neighborhood to represent the corresponding pixel in the current frame. Although remarkable improvement has been made with this method, the weight associated to each reference pixel is quite sensitive to the selection of its standard deviation. To address this issue, a dual probability is presented in this paper. Intuitively, it enhances those weights of pixels that are more similar to its counterpart in the current frame, while suppressing the rest of them. Experimental results show that the proposed method is effective to deal with intense motion and occlusion, especially in the case of reducing the adverse impact of noise.

We present a simple and versatile approach of using hydrogel microparticles to transfer both inorganic hydrophilic nanoparticles (NPs) such as CdTe quantum dots and enzymes such as lipase B from Candida antarctica (CalB) to organic media and eventually encapsulate them in the gel microparticles by consecutive exchange of the water swollen in the hydrogel microparticles with water-miscible organic solvents and water-immiscible solvents. The entrapment of hydrophilic nanoparticles is due to their incompatibility with water-immiscible organic solvents soaked in the gel matrices and in the surrounding environment, so the present approach obviates the need for any chemical modification to the NP surface or to the hydrogel and furthermore does not require any size matching or chemical affinity of the NPs for the hydrogel networks. The solvent exchange process causes little change of the intrinsic properties of hydrophilic nanoparticles; CdTe quantum dots encapsulated in hydrogel microparticles, dispersed in water-immiscible organic solvents, remain strongly fluorescent, and CalB retains high catalytic activity. Of importance is that the hydrophilic nanoparticles encapsulated in the gel microparticles in organic media can be completely recovered in aqueous media via reversed solvent exchange. As a consequence, the present approach should hold immense promise for technical applications, especially in catalysis.

The loss of information due to occlusion and other complications has been one of the main bottlenecks in the field of motion estimation. In this paper, we propose a novel motion estimation algorithm based on dual-tree complex wavelet (DT-CWT), which utilizes its approximate shift invariance and directional selectivity. Subbands within different orientations and levels are individually treated to overcome the issue of error propagation induced by frequently used coarse-to-fine searching strategy, as these subbands are approximately independent from each other. Then, the frame next to the current one is introduced to supplement the lost information due to the occlusion and to improve the estimation accuracy within boundary areas. Experimental results show that the proposed method is effective with robustness to intense motion, scene change and occlusion.