A series of mitochondria-targeting amphipathic prodrugs were developed and subsequently the relationship of different locations of TPP modification and molecular weights of mPEG for selective imaging and therapeutic targeting were tested. The aqueous self-assembled micelles can realize controlled release of free drug, with a faster release at alkaline pH.

Typical aggregation-induced emission enhancement fluorogens (AIEEgens) generally are designed as propeller-shaped molecules with multiple aromatic rotors. Described herein are 1,4-dihydropyridines, which have the minimum size necessary for AIEE, containing only a single ring, synthesized through a facile biocatalysis procedure. Owing to the AIEE property, intramolecular motion can be restrained by the surrounding environment, causing the radiative channel to open up. Both the fluorescence intensities and the lifetimes of the 1,4-dihydropyridine representatives increased with increasing viscosity, and high sensitivities were observed. On the basis of the single crystal X-ray structures, density functional theory (DFT) calculations were performed to explain the mechanism of the single-ring AIEE behaviour. Moreover, a few of the neutral AIEEgens were found to possess a high specificity towards mitochondria. As an example, one of the AIEEgens exhibited superior photostability and excellent storage tolerance, allowing for real-time imaging, viscosity mapping, and long-term tracking of the dynamics of the mitochondrial morphology.

AbstractA facile approach for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones was developed by a tandem multi-component reaction (MCR) in one pot. This approach involves two steps, lipase-catalyzed in situ generation of acetaldehyde and the Biginelli reaction in turn. Several control experiments were performed using acetaldehydes directly to explore the possible mechanism of this procedure. Moreover, owing to the distinct modularity and highly efficient features of the MCR, it can assemble libraries of structurally diverse products (yields up to 98% under the optimized conditions in this paper) and provides an exceptional synthesis tool for the discovery of the minimal deep-blue luminogen in the solid state, namely, a single ring.

Two novel fluorescent polymeric nanoparticles developed by the aqueous self-assembly of micelles exhibited the desired permeability for cell imaging. In particular, one of the fluorescent polymeric nanoparticles has been successfully used as an excellent intracellular pH sensor in whole living cells, based on PET inhibition.

An efficient synthesis of 2H-chromenones and 2-hydroxyl-2H-chromenones derivatives has been developed from 1,3-dicarbonyls and α,β-unsaturated aldehydes by a controllable regioselective domino cyclization reaction under catalysis of different lipases. 2H-Chromenones derivatives were synthesized by bovine pancreatic lipase (BPL) in acetonitrile, while lipase from Pseudomonas fluorescens (PFL) can catalyze the synthesis of the 2-hydroxyl-2H-chromenones derivatives in dichloromethane with moderate to high yields.

A series of novel aliphatic polyesters with azido functional groups were synthesized via the direct lipase-catalyzed polycondensation of dialkyl diester, diol and 2-azido-1,3-propanediol (azido glycerol) using immobilized lipase B from Candida antarctica (CALB). The effects of polymerization conditions including reaction time, temperature, enzyme amount, substrates and monomer feed ratio on the molecular weights of the products were studied. The polyesters with pendant azido groups were characterized by 1H NMR, 13C NMR, 2D NMR, FTIR, GPC and DSC. Alkyne end-functionalized poly(ethylene glycol) containing a cleavable acetal group was then grafted onto the polyester backbone by copper-catalyzed azide–alkyne cycloaddition (CuAAC, click chemistry). Using fluorescence spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM), these amphiphilic graft copolymers were found to readily self-assemble into nanosized micelles in aqueous solution with critical micelle concentrations between 0.70 and 1.97 mg L−1, and micelle sizes from 20–70 nm. The degradation of these polymers under acidic conditions was investigated by GPC and 1H NMR spectroscopy. Cell cytotoxicity tests indicated that the micelles had no apparent cytotoxicity to Bel-7402 cells, suggesting their potential as carriers for controlled drug delivery.

A two-step sequential biocatalytic process for the synthesis of chiral hydroxyesters that combines a lipase-catalyzed decarboxylative aldol reaction followed by kinetic resolution has been developed. The excellent combination of conventional and unconventional functions provides an attractive route for expanding the applications of biocatalysis.

A green and convenient protocol has been developed for asymmetric cross-aldol reaction. In this Letter, bovine pancreatic lipase (BPL) was first reported to catalyze the aldol reaction and acidic buffer was first used for promiscuous enzymatic aldol reaction.

A facile tandem route to α,β-unsaturated aldehydes was developed by combining the two catalytic activities of the same enzyme in a one-pot strategy for the aldol reaction and in situ generation of acetaldehyde. Lipase from Mucor miehei was found to have conventional and promiscuous catalytic activities for the hydrolysis of vinyl acetate and aldol condensation with in situ formed acetaldehyde. The first reaction continuously provided material for the second reaction, which effectively reduced the volatilization loss, oxidation, and polymerization of acetaldehyde, as well as avoided a negative effect on the enzyme of excessive amounts of acetaldehyde. After optimizing the process, several substrates participated in the reaction and provided the target products in moderate to high yields using this single lipase-catalyzed one-pot biotransformation.

•We develop an efficient, simple and economic process for purification of porcine pancreas lipase using aqueous two-phase system (ATPS).•Phase diagrams were determined to find an operating region for forming ATPS firstly.•We used stability ratio instead of TLL and without NaCl in the system.•This system obtained an enzyme partition coefficient of 12.7, the extraction efficiency of 94.7%, and the purification factor of approximately 4.An aqueous two-phase system (ATPS) was applied for the purification of porcine pancreatic lipase (PPL) from crude PPL using polyethylene glycol (PEG) and potassium phosphate. Phase diagrams for polyethylene glycol (PEG) and potassium phosphate dibasic were determined at room temperature to find an operating region to first form the ATPS. The PPL was preferentially partitioned into the PEG-rich phase in systems with molecular weights of 1000 and 1500 and concentrated in the phosphate-rich phase in systems with PEG of 4000. Moreover, instead of tie line length (TLL), we used a stability ratio without NaCl in the system, and we first applied fluorescence spectroscopy for the protein conformational analysis of the ATPS. The molecular weight of the purified lipase was determined to be approximately 52 kDa by SDS-PAGE. The enzyme was efficiently purified in PEG 1500/potassium phosphate (17/13, %) at a pH of 7.0 at 4 °C. This system obtained an enzyme partition coefficient of 12.7, an extraction efficiency of 94.7% and a purification factor of approximately 4. These results demonstrate that the aqueous two-phase system is a highly efficient method for PPL purification

Microemulsion-based organogels (MBGs) were effectively employed for the immobilization of four commonly used lipases. During the asymmetric hydrolysis of ketoprofen vinyl ester at 30 °C for 24 h, lipase from Rhizomucor miehei and Mucor javanicus immobilized in microemulsion-based organogels (RML MBGs and MJL MBGs) maintained good enantioselectivities (eep were 86.2% and 99.2%, respectively), and their activities increased 12.8-fold and 7.8-fold, respectively, compared with their free forms. They gave higher yields compared with other lipase MBGs and exhibited better enantioselectivity than commercial immobilized lipases. Immobilization considerably increased the tolerance to organic solvents and high temperature. Both MJL MBGs and RML MBGs showed excellent reusability during 30 cycles of repeated 24 h reactions at 30 °C (over 40 days). The system maintained yields of greater than 50%, while the ees values of RML MBGs and MJL MBGs remained nearly constant at 95% and 88%, respectively. Download full-size image

•Novel biocompatible surfactant-activated magnetic lipase CLEAs were developed.•Surfactant-activated magnetic CLEAs were applied in continuous biodiesel production.•Tween 80-activated magnetic CLEAs exhibited superior storage stability.•Good activity recovery was observed after 10 runs of biodiesel production.•No need to control the water content in biodiesel production.Novel surfactant-activated magnetic cross-linked enzyme aggregates of Thermomyces lanuginosus lipase (TLL-magnetic-CLEAs) were developed and provided an efficient approach to improve the activity and stability of lipase for biodiesel production. In the methanolysis of Jatropha oil for biodiesel synthesis, the maximum yield in isopropyl ether was 88% after 48 h at 40 °C, representing 3.5-fold and 2.5-fold higher activity than that exhibited by free TLL and TLL CLEAs, respectively. Moreover, Tween 80-activated TLL-magnetic-CLEAs retained their activity during storage at 4 °C for 11 weeks and 10 cycles of repeated 48 h biodiesel reactions at 40 °C (over 30 days). Additionally, the surface morphology, particle size and loading of lipase aggregates were confirmed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The combination of interfacial activation, high specific enzyme activity, improved stability and easy recovery of magnetic CLEAs presents an attractive process for lipase immobilization and provides a promising catalyst for biodiesel production.Download full-size image

Lipase from Candida rugosa (CRL) was immobilized in microemulsion-based organogels (MBGs) and subsequently applied in large scale synthesis of arylethyl acetate in organic solvents as a more stable and efficient catalyst. Various reaction parameters (solvent, temperature, substrate concentration) were investigated for enhancement of ester production. Thermal and operational stabilities were improved compared with free CRL showing its potential for continuous applications. They were more stable at 50–60 °C and showed good recovery activity, which retained 70% of their initial activity after 16 recycles in organic media and remained constant at that level thereafter. Moreover, the immobilized lipase can maintain high catalytic activity in a variety of organic solvents, while free lipase was easily inactivated in polar solvent. A series of alcohols with different substitution groups were successfully applied in CRL MBGs-catalyzed transesterification, affording higher conversions than those with the free enzyme.Graphical abstractDownload full-size imageHighlights► Lipase from Candida rugosa was coated with surfactants and immobilized in microemulsion-based organogels using AOT and its catalysis in organic solvents was explored. ► Immobilization increased the tolerance to organic solvent and high temperature. ► The reuse of CRL MBGs was up to 16 cycles of reaction at 50 °C. ► The low catalyst loading, mild reaction conditions, indicates the possibility of application in industrial chemical synthesis and other bulk applications.

An facile and green one-pot route has been developed for the synthesis of chromenes using salicylaldehyde and α,β-unsaturated ketones. α-Amylase from Bacillus subtilis shows excellent catalytic activity and exerts good adaptability to different substrates in the reaction. This promiscuous enzyme-catalyzed domino reaction not only extends the application of α-amylase from B. subtilis for new chemical transformations, but also provided an alternative synthetic method for 2H-chromene derivatives.Graphical abstractDownload full-size imageHighlights► The catalytic promiscuity of α-amylase for the synthesis of 2H-chromene derivatives was developed. ► α-Amylase from Bacillus subtilis shows excellent catalytic activity. ► The oxa-Michael addition and aldol reaction could be performed in one-pot and catalyzed by a single amylase. ► A wide range of substrates could effectively participate in this reaction and gave desired products.

•We build an efficient methodology to catalyze asymmetric cross aldol reaction.•Biocatalytic promiscuity combined with ionic liquids obtains excellent results.•We optimize reaction conditions carefully and adequately.•The used ionic liquid has preeminent ability of recycling.PPL (lipase from porcine pancreas) was found to catalyze asymmetric cross aldol reactions of aromatic and heteroaromatic aldehydes with various ketones in ionic liquid ([BMIM][PF6]) for the first time. Interestingly, PPL exhibited high catalytic activity and excellent stereoselectivity in this efficient and recyclable room temperature ionic liquid in the presence of moderate water, similar to the results obtained in organic solvents. High yields of up to 99%, excellent enantioselectivities of up to 90% ee, and good diastereoselectivities of up to >99:1 dr were achieved.Download full-size image

Several proteases, especially pepsin, were observed to directly catalyze asymmetric aldol reactions. Pepsin, which displays well-documented proteolytic activity under acidic conditions, exhibited distinct catalytic activity in a crossed aldol reaction between acetone and 4-nitrobenzaldehyde with high yield and moderate enantioselectivity. Fluorescence experiments indicated that under neutral pH conditions, pepsin maintains its native conformation and that the natural structure plays an important role in biocatalytic promiscuity. Moreover, no significant loss of enantioselectivity was found even after four cycles of catalyst recycling, showing the high stability of pepsin under the selected aqueous reaction conditions. This case of biocatalytic promiscuity not only expands the application of proteases to new chemical transformations, but also could be developed into a potentially valuable method for green organic synthesis.

•Lipase-catalyzed polycondensation synthesis of acid-degradable poly(β-thioether ester).•Novel poly(β-thioether ester-co-ε-caprolactone) copolymers with high molecular weights were obtained.•Poly(β-thioether ester) could rapidly degrade by the hydrolysis of the β-thiopropionate groups under acidic condition.A novel linear polyester with acid-labile β-thiopropionate groups was synthesized via the direct lipase-catalyzed polycondensation of methyl 3-((2-hydroxyethyl)thio)propanoate (MHETP) using immobilized lipase B from Candida antarctica (CALB). The influences of reaction conditions such as polymerization temperature and time on the molecular weight of the poly(β-thioether ester) (PTE) were studied. Ring-opening and condensation copolymerization of MHETP with ε-caprolactone (CL) led to the synthesis of novel poly(β-thioether ester-co-ε-caprolactone) copolymers, poly(TE-co-CL), with well-defined composition and narrow polydispersity. The random copolymers were characterized by 1H NMR, 13C NMR, 2D NMR, GPC, TGA and DSC. The degradation of the poly(β-thioether ester) under acidic conditions was investigated by GPC and 1H NMR spectroscopy.Download full-size image

•Aspergillus terreus lipase was immobilized into Alg-g-PEG/α-CD hollow nanospheres.•The immobilized lipase showed much higher ability to catalyze reactions.•The immobilized lipase was excellent in reusability and storage ability.The aim of this study was to improve the ability of Aspergillus terreus lipase to separate the racemic ketoprofen vinyl ester into individual enantiomers using hollow self-assembly alginate-graft-poly(ethylene glycol)/α-cyclodextrins (Alg-g-PEG/α-CD) spheres as enzyme immobilization carriers. The morphology and size of the Alg-g-PEG/α-CD particles were investigated by transmission electron microscopy (TEM) and were found to be nanoscale. To facilitate recycling, calcium alginate (CA) beads were developed to encapsulate Alg-g-PEG/α-CD particles, thereby producing Alg-g-PEG/α-CD/CA composite beads. The influence of buffer pH and enzyme concentration during immobilization was studied along with the biocatalyst's kinetic parameters. When the immobilized enzyme was under optimal conditions in the resolution reaction, maximal conversion (approximately 45.9%) and enantioselectivity (approximately 128.8) were obtained. The immobilized A. terreus lipase maintained excellent performance even after 20 reuses and retained nearly 100% of its original activity after 24 weeks of storage at 4 °C.Download full-size image

•A simple, mild, one-pot tandem method catalyzed by trypsin was developed for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones.•Trypsin was found to display dual promiscuous functions to catalyze transesterification and the Biginelli reaction in sequence.•A Biginelli reaction using in situ-produced acetaldehyde was developed.•The 3,4-dihydropyrimidin-2(1H)-ones were synthesized through one-pot tandem reaction.•Trypsin displayed its dual promiscuous functions.A simple, mild, one-pot tandem method catalyzed by trypsin was developed for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones by the Biginelli reaction of urea, β-dicarbonyl compounds, and in situ-formed acetaldehyde. Trypsin was found to display dual promiscuous functions to catalyze transesterification and the Biginelli reaction in sequence.

Typical aggregation-induced emission enhancement fluorogens (AIEEgens) generally are designed as propeller-shaped molecules with multiple aromatic rotors. Described herein are 1,4-dihydropyridines, which have the minimum size necessary for AIEE, containing only a single ring, synthesized through a facile biocatalysis procedure. Owing to the AIEE property, intramolecular motion can be restrained by the surrounding environment, causing the radiative channel to open up. Both the fluorescence intensities and the lifetimes of the 1,4-dihydropyridine representatives increased with increasing viscosity, and high sensitivities were observed. On the basis of the single crystal X-ray structures, density functional theory (DFT) calculations were performed to explain the mechanism of the single-ring AIEE behaviour. Moreover, a few of the neutral AIEEgens were found to possess a high specificity towards mitochondria. As an example, one of the AIEEgens exhibited superior photostability and excellent storage tolerance, allowing for real-time imaging, viscosity mapping, and long-term tracking of the dynamics of the mitochondrial morphology.