Chemical Engineering of Artificial Transcription Factors by Orthogonal Palladium(II)-Mediated S-Arylation Reactions

Site-selective functionalization strategies are in high demand to prepare well-defined homogeneous proteins for basic research and biomedical applications. In this regard, cysteine-based reactions have enabled a broad set of transformations to produce modified proteins for various applications. However, these approaches were mainly employed to modify a single reactive site with a specific transformation. Achieving site selectivity or multiple transformations, essential for preparing complex biomolecules, remains challenging. Herein we demonstrate the power of combining palladium(II)-mediated C-S bond formation and C-S bond cleavage reactions to selectively edit desired cysteine sites in complex and uniquely modified proteins. We developed an orthogonal palladium(II) strategy for rapid and effective diversification of multiple cysteine sites (3-6 residues) with various transformations. Importantly, we employed our approach to prepare 10 complex analogues, including modified, stapled, and multimeric proteins on a milligram scale. Furthermore, we also synthesized a focused library of stabilized artificial transcription factors that displayed enhanced stability and potent DNA binding activity. Our approach enables rapid and effective protein editing and opens new avenues to engineer new biomolecules for fundamental research and therapeutic applications.

Mutable Collagenous Tissue: A Concept Generator for Biomimetic Materials and Devices

Echinoderms (starfish, sea-urchins and their close relations) possess a unique type of collagenous tissue that is innervated by the motor nervous system and whose mechanical properties, such as tensile strength and elastic stiffness, can be altered in a time frame of seconds. Intensive research on echinoderm 'mutable collagenous tissue' (MCT) began over 50 years ago, and over 20 years ago, MCT first inspired a biomimetic design. MCT, and sea-cucumber dermis in particular, is now a major source of ideas for the development of new mechanically adaptable materials and devices with applications in diverse areas including biomedical science, chemical engineering and robotics. In this review, after an up-to-date account of present knowledge of the structural, physiological and molecular adaptations of MCT and the mechanisms responsible for its variable tensile properties, we focus on MCT as a concept generator surveying biomimetic systems inspired by MCT biology, showing that these include both bio-derived developments (same function, analogous operating principles) and technology-derived developments (same function, different operating principles), and suggest a strategy for the further exploitation of this promising biological resource.

Protein fibers with self-recoverable mechanical properties via dynamic imine chemistry

The manipulation of internal interactions at the molecular level within biological fibers is of particular importance but challenging, severely limiting their tunability in macroscopic performances and applications. It thus becomes imperative to explore new approaches to enhance biological fibers' stability and environmental tolerance and to impart them with diverse functionalities, such as mechanical recoverability and stimulus-triggered responses. Herein, we develop a dynamic imine fiber chemistry (DIFC) approach to engineer molecular interactions to fabricate strong and tough protein fibers with recoverability and actuating behaviors. The resulting DIF fibers exhibit extraordinary mechanical performances, outperforming many recombinant silks and synthetic polymer fibers. Remarkably, impaired DIF fibers caused by fatigue or strong acid treatment are quickly recovered in water directed by the DIFC strategy. Reproducible mechanical performance is thus observed. The DIF fibers also exhibit exotic mechanical stability at extreme temperatures (e.g., -196 °C and 150 °C). When triggered by humidity, the DIFC endows the protein fibers with diverse actuation behaviors, such as self-folding, self-stretching, and self-contracting. Therefore, the established DIFC represents an alternative strategy to strengthen biological fibers and may pave the way for their high-tech applications.

Engineering a potent boron-10-enriched polymeric nanoparticle for boron neutron capture therapy

Background: Boron neutron capture therapy (BNCT) is a promising cancer treatment that eliminates tumor cells by triggering high-energy radiation within cancer cells. Aim: In vivo evaluation of poly(vinyl alcohol)/boric acid crosslinked nanoparticles (PVA/BA NPs) for BNCT. Materials & methods: PVA/BA NPs were synthesized and intravenously injected into tumor-bearing mice for BNCT. Results: The in vitro boron uptake of PVA/BA NPs in tumor cells was 70-fold higher than the required boron uptake for successful BNCT. In an in vivo study, PVA/BA NPs showed a 44.29% reduction in tumor size compared with clinically used boronophenylalanine for oral cancer in a murine model. Conclusion: PVA/BA NPs exhibited effective therapeutic results for oral cancer treatments in BNCT.

Pre-lab video demonstrations to enhance students' laboratory experience in a first-year chemical engineering class

The limited capabilities of teaching laboratories, combined with an increasing number of students enrolled in university, require constant augmentation of instructional approaches. By enhancing laboratory demonstrations with digital technology, these structural issues can be addressed while at the same time enhancing student understanding and learning. Our case study focuses on the fermentation lab part of the Reaction Equilibria and Thermodynamics (RET) module, a first-year chemical engineering course at the University of Birmingham. Video demonstrations were used to introduce students to the laboratory set-ups and walk them through each step and technique. The video demonstrations allowed the students to attend the in-person lab sessions having established knowledge and understanding of the processes involved and the outcomes desired, which decreased the burden on the facilities and the staff. A knowledge-based quiz and a student survey conducted at the end of the module showed that the pre-lab videos encouraged more active participation in the laboratory sessions and reinforced learning. Approximately 70% of the students polled in the first survey conducted within this project felt more confident going into the laboratory sessions after watching the pre-lab videos and attempting the knowledge quiz, while 92% of the students polled in the second survey judged the pre-lab video sessions as beneficial to them. Overall, the teaching method has the potential to improve student participation and access, boost confidence and learning, and provided a more structured and flexible approach to laboratory learning outcomes.

Sequence and Structure-Guided Engineering of Urethanase from Agrobacterium tumefaciens d3 for Improved Catalytic Activity

The amidase from Agrobacterium tumefaciens d3 (AmdA) degrades the carcinogenic ethyl carbamate (EC) in alcoholic beverages. However, its limited catalytic activity hinders practical applications. Here, multiple sequence alignment was first used to predict single variants with improved activity. Afterward, AlphaFold 2 was applied to predict the three-dimensional structure of AmdA and 21 amino acids near the catalytic triad were randomized by saturation mutagenesis. Each of the mutation libraries was then screened, and the improved single variants were combined to obtain the best double variant I97L/G195A that showed a 3.1-fold increase in the urethanase activity and a 1.5-fold increase in ethanol tolerance. MD simulations revealed that the mutations shortened the distance between catalytic residues and the substrate and enhanced the occurrence of a critical hydrogen bond in the catalytic pocket. This study displayed a useful strategy to engineer an amidase for the improvement of urethanase activity, and the variant obtained provided a good candidate for applications in the food industry.

Smart Chemical Engineering-Based Lightweight and Miniaturized Attachable Systems for Advanced Drug Delivery and Diagnostics

Smart attachable systems have attracted much attention owing to their capabilities in terms of body performance evaluation, disease diagnostics, and drug delivery. Recent advances in chemical and engineering techniques provide many opportunities to improve device fabrication and applications owing to the advantages of being lightweight and easy to control as well as their battery absence and functional diversity. This review highlights the latest developments in the field of chemical engineering-based lightweight and miniaturized attachable systems, which are mainly inspired by the natural world. Their applications for real-time monitoring, point-of-care sampling, biomarker detection, and controlled release are discussed thoroughly with respect to specific products/prototypes. The perspectives of the field, including persistence guarantee, burden reduction, and personality improvement, are also discussed. It is believed that chemical engineering-based lightweight and miniaturized attachable systems have good potential in both clinical and industrial fields, indicating a large potential to improve human lives in the near future.

Chemical Reaction Engineering to Understand Applied Kinetics in Free Enzyme Homogeneous Reactors

Chemical reaction engineering is interested in elucidating the reaction kinetics through the determination of the fundamental influencing variables. The understanding of enzyme kinetics is needed to implement the potential of enzymes to satisfy determined production targets and for the design of the reactor. The quantification of the enzyme kinetics is implemented by the elucidation and building of the kinetic model (it includes one or more kinetic equations). In the context of process development, the kinetic model is not only useful to identify feasibility and for optimizing reaction conditions but also, at an early stage of development it is very useful to anticipate implementation bottlenecks, and so guide reactor setup. In this chapter we describe theoretical and practical considerations to illustrate the methodological framework of kinetic analysis. We take as study cases four archetypal kinetic cases by using as example the hydrolysis of cellobiose catalyzed by a beta-glucosidase. We show the different experimental data that can be obtained by the monitoring of enzymatic reactions in different configuration of free enzyme homogeneous ideal reactors; we show step-by-step the visualization, treatment, and analysis of data to elucidate kinetic models and the procedure for the quantification of kinetic constants. Finally, the performance of different reactors is compared in the interplay with the enzyme kinetics. This book chapter aims at being useful for a broad multidisciplinary audience and different levels of academic development.

Engineering a Remedy to Modulate and Optimize Biopharmaceutical Properties of Rebamipide by Synthesizing New Cocrystal: In Silico and Experimental Studies

PURPOSE

Rebamipide (REB) a potent anti-ulcer agent, has not been exploited to its full potential, owing to it extremely poor solubility, leading to highly diminutive bioavailability (<10%). The purpose is to carry out its solid-state modification.

METHOD

Cocrystallisation was done with three GRAS coformers namely citric acid (CA), 3,4-dihydroxybenzoic acid (DHBA) and oxalic acid (OXA) employing the liquid-assisted grinding method. Cocrystal formation was based upon amide-carboxyl and amide-hydroxyl supramolecular synthons. Characterization of novel cocrystals i.e. RCA, RDHBA and ROXA was carried out by DSC, PXRD and additionally by FT-IR spectroscopy. Chemical structures have been determined utilizing the PXRD pattern by Material Studio®. Furthermore, cocrystals were subjected to solubility and intrinsic dissolution rate (IDR) evaluation. Also, pharmacodynamic and pharmacokinetic studies were performed and compared with pure rebamipide.

RESULT

The appearances of a single sharp melting endotherm in DSC, along with novel characteristic peaks in PXRD infer the existence of a new crystalline form. Shifting in characteristic vibrations in FT-IR spectroscopy supports the establishment of distinct hydrogen-bonded networks. Structural determination revealed that RCA crystallizes in 'Bb2b' space groups whereas RDHBA in 'P1' and ROXA crystallize out in the 'P-1' space group. All the cocrystals exhibited superior apparent solubility and almost 7-13 folds increase in IDR. Furthermore, 1.6-2.5 folds enhancement in relative bioavailability and remarkable amplification in anti-ulcer, anti-inflammatory and the antioxidant potential of these cocrystals were observed.

CONCLUSION

The study ascertains the advantages of cocrystallization, with RCA showing greatest potential and suggests a viable alternative approach for improved formulation of rebamipide.

Facile synthesis of near-infrared bodipy by donor engineering for in vivo tumor targeted dual-modal imaging

Bodipy is one of the most popular dyes for bioimaging, however, a complicated synthetic protocol is needed to create and isolate ideal near-infrared (NIR) emissive Bodipy derivatives for optical bioimaging. It is noticed that the donor species impact the wavelength when the π-conjugation system of green light emissive Bodipy is elongated via a one-step reaction. Herein, several Bodipy dyes bearing different common donors are synthesized. Their optical properties confirm that both absorption and emission peaks of the synthesized Bodipy could be tuned to NIR wavelength by using stronger donors via a facile reaction. The synthesized monocarboxyl Bodipy could conjugate with aminated PEG to yield an amphiphilic polymer, which further self-assembles into a NIR nanoparticle (NP). The NIR NP exhibits preferential tumor accumulation via the enhanced permeation and retention (EPR) effect, making it useful for tumor diagnosis by both fluorescence imaging and photoacoustic tomography.

Chemical engineering of bacterial effectors for regulating cell signaling and responses

Bacteria have evolved a variety of effector proteins to facilitate their survival and proliferation within the host environment. Continuous competition at the host-pathogen interface has empowered these effectors with unique mechanism and high specificity toward their host targets. The rich repertoire of bacterial effectors has thus provided us an attractive toolkit for investigating various cellular processes, such as signal transductions. With recent advances in protein chemistry and engineering, we now have the capability for on-demand control of protein activity with high precision. Herein, we review the development of chemically engineered bacterial effectors to control kinase-mediated signal transductions, inhibit protein translation, and direct genetic editing within host cells. We also highlight future opportunities for harnessing diverse prokaryotic effectors as powerful tools for mechanistic investigation and therapeutic intervention of eukaryotic systems.

Remediation of heavy metal contamination of sediments and soils using ligand-coated dense nanoparticles

Sediment and soil contamination with toxic heavy metals, including cadmium (Cd²⁺) and lead (Pb²⁺), represents a major long-term remediation challenge. Resuspension of contaminated sediments into the water column, or the uptake of toxic metals from top soil, can lead to exposure of aquatic or terrestrial organisms, followed by bioconcentration, bioaccumulation and biomagnification, which may pose a threat to public health. We have developed a novel nanoscale engineered material, namely ligand-coated dense nanoparticles (Ligand DNPs), which contain a dense WO₃ nanoparticle core and a shell functionalized with a metal-binding organic ligand (EDTA), to effectively sequester heavy metal ions deeper into the soil and sediments. We demonstrate that one application of Ligand DNPs can remove from 60% to almost 80% of the Cd and Pb in two different soil matrices, driving these metal ions deeper into the sediment or soil column via gravity, and making them less bioavailable. Ligand DNPs can provide a relatively fast, convenient, and efficient in-situ approach for the remediation of sediments and soils contaminated with heavy metals.

[Intergrating problem-based-learning with flipped classroom teaching in "Principles of chemical engineering" for biological engineering undergraduates]

New engineering program requires training models that conform acceptable time span and principles of engineering education. Considering the program "Principles of chemical engineering" and the limitations of traditional teaching methods, we integrated problem-based learning method and flipped classroom teaching model to reform the course. Through a three-stage systematic teaching design including knowledge learning before class, knowledge internalization in class, and consolidation and expansion after class, we effectively stimulated students' interest and enthusiasm in learning, cultivated students' independent learning ability and engineering thinking, and achieved good teaching effect. It can provide reference for the construction of "Principles of chemical engineering" course and training of engineering talents in agricultural colleges.

Reconfigurable microbots folded from simple colloidal chains

To overcome the reversible nature of low-Reynolds-number flow, a variety of biomimetic microrobotic propulsion schemes and devices capable of rapid transport have been developed. However, these approaches have been typically optimized for a specific function or environment and do not have the flexibility that many real organisms exhibit to thrive in complex microenvironments. Here, inspired by adaptable microbes and using a combination of experiment and simulation, we demonstrate that one-dimensional colloidal chains can fold into geometrically complex morphologies, including helices, plectonemes, lassos, and coils, and translate via multiple mechanisms that can be varied with applied magnetic field. With chains of multiblock asymmetry, the propulsion mode can be switched from bulk to surface-enabled, mimicking the swimming of microorganisms such as flagella-rotating bacteria and tail-whipping sperm and the surface-enabled motion of arching and stretching inchworms and sidewinding snakes. We also demonstrate that reconfigurability enables navigation through three-dimensional and narrow channels simulating capillary blood vessels. Our results show that flexible microdevices based on simple chains can transform both shape and motility under varying magnetic fields, a capability we expect will be particularly beneficial in complex in vivo microenvironments.

Lipid sponge droplets as programmable synthetic organelles

Living cells segregate molecules and reactions in various subcellular compartments known as organelles. Spatial organization is likely essential for expanding the biochemical functions of synthetic reaction systems, including artificial cells. Many studies have attempted to mimic organelle functions using lamellar membrane-bound vesicles. However, vesicles typically suffer from highly limited transport across the membranes and an inability to mimic the dense membrane networks typically found in organelles such as the endoplasmic reticulum. Here, we describe programmable synthetic organelles based on highly stable nonlamellar sponge phase droplets that spontaneously assemble from a single-chain galactolipid and nonionic detergents. Due to their nanoporous structure, lipid sponge droplets readily exchange materials with the surrounding environment. In addition, the sponge phase contains a dense network of lipid bilayers and nanometric aqueous channels, which allows different classes of molecules to partition based on their size, polarity, and specific binding motifs. The sequestration of biologically relevant macromolecules can be programmed by the addition of suitably functionalized amphiphiles to the droplets. We demonstrate that droplets can harbor functional soluble and transmembrane proteins, allowing for the colocalization and concentration of enzymes and substrates to enhance reaction rates. Droplets protect bound proteins from proteases, and these interactions can be engineered to be reversible and optically controlled. Our results show that lipid sponge droplets permit the facile integration of membrane-rich environments and self-assembling spatial organization with biochemical reaction systems.

Programming nanoparticle valence bonds with single-stranded DNA encoders

Nature has evolved strategies to encode information within a single biopolymer to program biomolecular interactions with characteristic stoichiometry, orthogonality and reconfigurability. Nevertheless, synthetic approaches for programming molecular reactions or assembly generally rely on the use of multiple polymer chains (for example, patchy particles). Here we demonstrate a method for patterning colloidal gold nanoparticles with valence bond analogues using single-stranded DNA encoders containing polyadenine (polyA). By programming the order, length and sequence of each encoder with alternating polyA/non-polyA domains, we synthesize programmable atom-like nanoparticles (PANs) with n-valence that can be used to assemble a spectrum of low-coordination colloidal molecules with different composition, size, chirality and linearity. Moreover, by exploiting the reconfigurability of PANs, we demonstrate dynamic colloidal bond-breaking and bond-formation reactions, structural rearrangement and even the implementation of Boolean logic operations. This approach may be useful for generating responsive functional materials for distinct technological applications.

Ordered three-dimensional nanomaterials using DNA-prescribed and valence-controlled material voxels

The ability to organize nanoscale objects into well-defined three-dimensional (3D) arrays can translate advances in nanoscale synthesis into targeted material fabrication. Despite successes in nanoparticle assembly, most extant methods are system specific and not fully compatible with biomolecules. Here, we report a platform for creating distinct 3D ordered arrays from different nanomaterials using DNA-prescribed and valence-controlled material voxels. These material voxels consist of 3D DNA frames that integrate nano-objects within their scaffold, thus enabling the object's valence and coordination to be determined by the frame's vertices, which can bind to each other through hybridization. Such DNA material voxels define the lattice symmetry through the spatially prescribed valence decoupling the 3D assembly process from the nature of the nanocomponents, such as their intrinsic properties and shapes. We show this by assembling metallic and semiconductor nanoparticles and also protein superlattices. We support the technological potential of such an assembly approach by fabricating light-emitting 3D arrays with diffraction-limited spectral purity and 3D enzymatic arrays with increased activity.

Formation of a hard surface layer during drying of a heated porous media

We report surface hardening or crust formation, like caking, during evaporation when a porous medium was heated from above using IR radiation. These crusts had higher strength than their closest counterparts such as sandcastles and mud-peels which essentially are clusters of a partially wet porous medium. Observed higher strength of the crusts was mostly due to surface tension between the solid particles, which are connected by liquid bridges (connate water). Qualitative (FTIR) and quantitative (TGA) measurements confirmed the presence of trapped water within the crust. Based on the weight measurements, the amount of water trapped in the crusts was ~1.5%; trapped water was also seen as liquid bridges in the SEM images. Further, in the fixed particle sizes case, the crust thickness varied slightly (only 10–20 particle diameters for cases with external heating) while with the natural sand whole porous column was crusted; surprisingly, the crust was also found with the hydrophobic glass beads. Fluorescein dye visualization technique was used to determine the crust thickness. We give a power-law relation between the crust thickness and the incident heat flux for various particle sizes. The strength of the crust decreased drastically with increasing hydrophilic spheres diameter while it increased with higher surface temperature.

Engineering Anticancer Amphipathic Peptide-Dendronized Compounds for Highly-Efficient Plasma/Organelle Membrane Perturbation and Multidrug Resistance Reversal

Discovering new strategies for combating drug-resistant tumors becomes a worldwide challenge. Thereinto, stubborn drug-resistant tumor membrane is a leading obstacle on chemotherapy. Herein, we report a novel tumor-activatable amphipathic peptide-dendronized compound, which could form nanoaggregates in aqueous solutions, for perturbing tumor plasma/organelle membrane and reversing multidrug resistance. Distinguished from classical linear amphipathic peptide drugs for membrane disturbance, dendritic lysine-based architecture is designed as a multivalent scaffold to amplify the supramolecular interactions of cationic compound with drug-resistant tumor membrane. Moreover, arginine-rich residues as terminal groups are hopeful to generate multiple hydrogen bonding and electrostatic interactions with tumor membrane. On the other hand, antitumor molecule (doxorubicin) is devised as a hydrophobic moiety to intensify the membrane-inserting ability owing to the prominent interactions with hydrophobic domains of drug-resistant tumor membrane. As expected, these amphipathic peptide-dendronized compounds within the nanoaggregates could severely disturb both the structures and functions of tumor plasma/organelle membrane system, thereby resulting in the rapid leakage of many critical biomolecules, highly efficient apoptotic activation and antiapoptotic inhibition. This strategy on tumor membrane perturbation demonstrates a bran-new antitumor activity with high contributions to cell cycle arrest (at the S phase), strong apoptosis-inducing ability and satisfying cytotoxicity to a variety of drug-resistant tumor cell lines.

Remediation of water and wastewater by using engineered nanomaterials: A review

Nanotechnology is currently a fast-rising socioeconomic and political knowledge-based technology owing to the unique characteristics of its engineered nanomaterials. This branch of technology is useful for water and wastewater remediation. Many scientists and researchers have been conducting different studies and experiments on the applications of engineered nanomaterials at the local to international level. This review mainly aims to provide a current overview of existing knowledge on engineered nanomaterials and their applications in water and wastewater remediation. Furthermore, the present risks and challenges of nanotechnology are examined.

Depth treatment of coal-chemical engineering wastewater by a cost-effective sequential heterogeneous Fenton and biodegradation process

In this study, a sequential Fe⁰/H₂O₂ reaction and biological process was employed as a low-cost depth treatment method to remove recalcitrant compounds from coal-chemical engineering wastewater after regular biological treatment. First of all, a chemical oxygen demand (COD) and color removal efficiency of 66 and 63% was achieved at initial pH of 6.8, 25 mmol L^-1 of H₂O₂, and 2 g L^-1 of Fe⁰ in the Fe⁰/H₂O₂ reaction. According to the gas chromatography-mass spectrometer (GC-MS) and gas chromatography-flame ionization detector (GC-FID) analysis, the recalcitrant compounds were effectively decomposed into short-chain organic acids such as acetic, propionic, and butyric acids. Although these acids were resistant to the Fe⁰/H₂O₂ reaction, they were effectively eliminated in the sequential air lift reactor (ALR) at a hydraulic retention time (HRT) of 2 h, resulting in a further decrease of COD and color from 120 to 51 mg L^-1 and from 70 to 38 times, respectively. A low operational cost of 0.35 $ m^-3 was achieved because pH adjustment and iron-containing sludge disposal could be avoided since a total COD and color removal efficiency of 85 and 79% could be achieved at an original pH of 6.8 by the above sequential process with a ferric ion concentration below 0.8 mg L^-1 after the Fe⁰/H₂O₂ reaction. It indicated that the above sequential process is a promising and cost-effective method for the depth treatment of coal-chemical engineering wastewaters to satisfy discharge requirements.

Toxicology of Engineered Nanoparticles: Focus on Poly(amidoamine) Dendrimers

Engineered nanomaterials are increasingly being developed for paints, sunscreens, cosmetics, industrial lubricants, tyres, semiconductor devices, and also for biomedical applications such as in diagnostics, therapeutics, and contrast agents. As a result, nanomaterials are being manufactured, transported, and used in larger and larger quantities, and potential impacts on environmental and human health have been raised. Poly(amidoamine) (PAMAM) dendrimers are specifically suitable for biomedical applications. They are well-defined nanoscale molecules which contain a 2-carbon ethylenediamine core and primary amine groups at the surface. The systematically variable structural architecture and the large internal free volume make these dendrimers an attractive option for drug delivery and other biomedical applications. Due to the wide range of applications, the Organisation for Economic Co-Operation and Development (OECD) have included them in their list of nanoparticles which require toxicological assessment. Thus, the toxicological impact of these PAMAM dendrimers on human health and the environment is a matter of concern. In this review, the potential toxicological impact of PAMAM dendrimers on human health and environment is assessed, highlighting work to date exploring the toxicological effects of PAMAM dendrimers.

Risks, Release and Concentrations of Engineered Nanomaterial in the Environment

For frequently used engineered nanomaterials (ENMs) CeO2-, SiO2-, and Ag, past, current, and future use and environmental release are investigated. Considering an extended period (1950 to 2050), we assess ENMs released through commercial activity as well as found in natural and technical settings. Temporal dynamics, including shifts in release due to ENM product application, stock (delayed use), and subsequent end-of-life product treatment were taken into account. We distinguish predicted concentrations originating in ENM use phase and those originating from end-of-life release. Furthermore, we compare Ag- and CeO2-ENM predictions with existing measurements. The correlations and limitations of the model, and the analytic validity of our approach are discussed in the context of massive use of assumptive model data and high uncertainty on the colloidal material captured by the measurements. Predictions for freshwater CeO2-ENMs range from 1 pg/l (2017) to a few hundred ng/l (2050). Relative to CeO2, the SiO2-ENMs estimates are approximately 1,000 times higher, and those for Ag-ENMs 10 times lower. For most environmental compartments, ENM pose relatively low risk; however, organisms residing near ENM 'point sources' (e.g., production plant outfalls and waste treatment plants), which are not considered in the present work, may be at increased risk.

Droplets As Liquid Robots

Liquid droplets are very simple objects present in our everyday life. They are extremely important for many natural phenomena as well as for a broad variety of industrial processes. The conventional research areas in which the droplets are studied include physical chemistry, fluid mechanics, chemical engineering, materials science, and micro- and nanotechnology. Typical studies include phenomena such as condensation and droplet formation, evaporation of droplets, or wetting of surfaces. The present article reviews the recent literature that employs droplets as animated soft matter. It is argued that droplets can be considered as liquid robots possessing some characteristics of living systems, and such properties can be applied to unconventional computing through maze solving or operation in logic gates. In particular, the lifelike properties and behavior of liquid robots, namely (i) movement, (ii) self-division, and (iii) group dynamics, will be discussed.

Spontaneous Isopeptide Bond Formation as a Powerful Tool for Engineering Site-Specific Antibody-Drug Conjugates

Spontaneous isopeptide bond formation, a stabilizing posttranslational modification that can be found in gram-positive bacterial cell surface proteins, has previously been used to develop a peptide-peptide ligation technology that enables the polymerization of tagged-proteins catalyzed by SpyLigase. Here we adapted this technology to establish a novel modular antibody labeling approach which is based on isopeptide bond formation between two recognition peptides, SpyTag and KTag. Our labeling strategy allows the attachment of a reporting cargo of interest to an antibody scaffold by fusing it chemically to KTag, available via semi-automated solid-phase peptide synthesis (SPPS), while equipping the antibody with SpyTag. This strategy was successfully used to engineer site-specific antibody-drug conjugates (ADCs) that exhibit cytotoxicities in the subnanomolar range. Our approach may lead to a new class of antibody conjugates based on peptide-tags that have minimal effects on protein structure and function, thus expanding the toolbox of site-specific antibody conjugation.

Skin-inspired hydrogel-elastomer hybrids with robust interfaces and functional microstructures

Inspired by mammalian skins, soft hybrids integrating the merits of elastomers and hydrogels have potential applications in diverse areas including stretchable and bio-integrated electronics, microfluidics, tissue engineering, soft robotics and biomedical devices. However, existing hydrogel-elastomer hybrids have limitations such as weak interfacial bonding, low robustness and difficulties in patterning microstructures. Here, we report a simple yet versatile method to assemble hydrogels and elastomers into hybrids with extremely robust interfaces (interfacial toughness over 1,000 Jm(-2)) and functional microstructures such as microfluidic channels and electrical circuits. The proposed method is generally applicable to various types of tough hydrogels and diverse commonly used elastomers including polydimethylsiloxane Sylgard 184, polyurethane, latex, VHB and Ecoflex. We further demonstrate applications enabled by the robust and microstructured hydrogel-elastomer hybrids including anti-dehydration hydrogel-elastomer hybrids, stretchable and reactive hydrogel-elastomer microfluidics, and stretchable hydrogel circuit boards patterned on elastomer.

Tough bonding of hydrogels to diverse non-porous surfaces

In many animals, the bonding of tendon and cartilage to bone is extremely tough (for example, interfacial toughness ∼800 J m(-2); refs ,), yet such tough interfaces have not been achieved between synthetic hydrogels and non-porous surfaces of engineered solids. Here, we report a strategy to design tough transparent and conductive bonding of synthetic hydrogels containing 90% water to non-porous surfaces of diverse solids, including glass, silicon, ceramics, titanium and aluminium. The design strategy is to anchor the long-chain polymer networks of tough hydrogels covalently to non-porous solid surfaces, which can be achieved by the silanation of such surfaces. Compared with physical interactions, the chemical anchorage results in a higher intrinsic work of adhesion and in significant energy dissipation of bulk hydrogel during detachment, which lead to interfacial toughness values over 1,000 J m(-2). We also demonstrate applications of robust hydrogel-solid hybrids, including hydrogel superglues, mechanically protective hydrogel coatings, hydrogel joints for robotic structures and robust hydrogel-metal conductors.

Conference report "Stoffwechsel. Histories of metabolism", workshop organized by Mathias Grote at Technische Universität Berlin, November 28-29th, 2014

Historical analyses of what metabolism has been conceived of, how concepts of metabolism were related to disciplines such as nineteenth-century nutritional physiology or twentieth-century biochemistry, and how their genealogies relate to the current developments may be helpful to understand the various, at times polemic, ways in which the boundaries between metabolism and heredity have been re-drawn. Against this background, a small number of scholars gathered in Berlin for a workshop that equally aimed at bringing new stories to the fore, and at considering seemingly known ones in a new light. Some aspects of the discussions are summarized in this paper.

[Progress in industrial bioprocess engineering in China]

The advances of industrial biotechnology highly depend on the development of industrial bioprocess researches. In China, we are facing several challenges because of a huge national industrial fermentation capacity. The industrial bioprocess development experienced several main stages. This work mainly reviews the development of the industrial bioprocess in China during the past 30 or 40 years: including the early stage kinetics model study derived from classical chemical engineering, researching method based on control theory, multiple-parameter analysis techniques of on-line measuring instruments and techniques, and multi-scale analysis theory, and also solid state fermentation techniques and fermenters. In addition, the cutting edge of bioprocess engineering was also addressed.

Biofuels. Engineering alcohol tolerance in yeast

Ethanol toxicity in the yeast Saccharomyces cerevisiae limits titer and productivity in the industrial production of transportation bioethanol. We show that strengthening the opposing potassium and proton electrochemical membrane gradients is a mechanism that enhances general resistance to multiple alcohols. The elevation of extracellular potassium and pH physically bolsters these gradients, increasing tolerance to higher alcohols and ethanol fermentation in commercial and laboratory strains (including a xylose-fermenting strain) under industrial-like conditions. Production per cell remains largely unchanged, with improvements deriving from heightened population viability. Likewise, up-regulation of the potassium and proton pumps in the laboratory strain enhances performance to levels exceeding those of industrial strains. Although genetically complex, alcohol tolerance can thus be dominated by a single cellular process, one controlled by a major physicochemical component but amenable to biological augmentation.

[Insights into engineering of cellulosic ethanol]

For energy security, air pollution concerns, coupled with the desire to sustain the agricultural sector and revitalize the rural economy, many countries have applied ethanol as oxygenate or fuel to supplement or replace gasoline in transportation sector. Because of abundant feedstock resources and effective reduction of green-house-gas emissions, the cellulosic ethanol has attracted great attention. With a couple of pioneers beginning to produce this biofuel from biomass in commercial quantities around the world, it is necessary to solve engineering problems and complete the economic assessment in 2015-2016, gradually enter the commercialization stage. To avoid "competing for food with humans and competing for land with food", the 1st generation fuel ethanol will gradually transit to the 2nd generation cellulosic ethanol. Based on the overview of cellulosic ethanol industrialization from domestic and abroad in recent years, the main engineering application problems encountered in pretreatment, enzymes and enzymatic hydrolysis, pentose/hexose co-fermentation strains and processes, equipment were discussed from chemical engineering and biotechnology perspective. The development direction of cellulosic ethanol technology in China was addressed.

Universal process-inert encoding architecture for polymer microparticles

Polymer microparticles with unique, decodable identities are versatile information carriers with a small footprint. Widespread incorporation into industrial processes, however, is limited by a trade-off between encoding density, scalability and decoding robustness in diverse physicochemical environments. Here, we report an encoding strategy that combines spatial patterning with rare-earth upconversion nanocrystals, single-wavelength near-infrared excitation and portable CCD (charge-coupled device)-based decoding to distinguish particles synthesized by means of flow lithography. This architecture exhibits large, exponentially scalable encoding capacities (>10(6) particles), an ultralow decoding false-alarm rate (<10(-9)), the ability to manipulate particles by applying magnetic fields, and pronounced insensitivity to both particle chemistry and harsh processing conditions. We demonstrate quantitative agreement between observed and predicted decoding for a range of practical applications with orthogonal requirements, including covert multiparticle barcoding of pharmaceutical packaging (refractive-index matching), multiplexed microRNA detection (biocompatibility) and embedded labelling of high-temperature-cast objects (temperature resistance).

Comprehensive probabilistic modelling of environmental emissions of engineered nanomaterials

Concerns about the environmental risks of engineered nanomaterials (ENM) are growing, however, currently very little is known about their concentrations in the environment. Here, we calculate the concentrations of five ENM (nano-TiO2, nano-ZnO, nano-Ag, CNT and fullerenes) in environmental and technical compartments using probabilistic material-flow modelling. We apply the newest data on ENM production volumes, their allocation to and subsequent release from different product categories, and their flows into and within those compartments. Further, we compare newly predicted ENM concentrations to estimates from 2009 and to corresponding measured concentrations of their conventional materials, e.g. TiO2, Zn and Ag. We show that the production volume and the compounds' inertness are crucial factors determining final concentrations. ENM production estimates are generally higher than a few years ago. In most cases, the environmental concentrations of corresponding conventional materials are between one and seven orders of magnitude higher than those for ENM.

Macedonian journal of chemistry and chemical engineering: open journal systems--editor's perspective

The development and availability of personal computers and software as well as printing techniques in the last twenty years have made a profound change in the publication of scientific journals. Additionally, the Internet in the last decade has revolutionized the publication process to the point of changing the basic paradigm of printed journals. The Macedonian Journal of Chemistry and Chemical Engineering in its 40-year history has adopted and adapted to all these transformations. In order to keep up with the inevitable changes, as editor-in-chief I felt my responsibility was to introduce an electronic editorial managing of the journal. The choice was between commercial and open source platforms, and because of the limited funding of the journal we chose the latter. We decided on Open Journal Systems, which provided online submission and management of all content, had flexible configuration--requirements, sections, review process, etc., had options for comprehensive indexing, offered various reading tools, had email notification and commenting ability for readers, had an option for thesis abstracts and was installed locally. However, since there is limited support it requires a moderate computer knowledge/skills and effort in order to set up. Overall, it is an excellent editorial platform and a convenient solution for journals with a low budget or journals that do not want to spend their resources on commercial platforms or simply support the idea of open source software.

Adsorption, structural alteration and elution of peptides at pendant PEO layers

An experimentally based, quantitative understanding of the entrapment and function of small peptides within PEO brush layers does not currently exist. Earlier work provided a rationale for expecting that an ordered, compact peptide will enter the PEO phase more readily than a peptide of similar size that adopts a less ordered, less compact form, and that amphiphilicity will promote peptide retention within the hydrophobic region of the PEO brush. Here we more deliberately describe criteria for peptide integration and structural change within the PEO brush, and discuss the reversibility of peptide entrapment with changing solvent conditions. For this purpose, circular dichroism (CD) was used to record the adsorption and conformational changes of (amphiphilic) WLBU2 and (non-amphiphilic) polyarginine peptides at uncoated (hydrophobic) and PEO-coated silica nanoparticles. Peptide conformation was controlled between disordered and α-helical forms by varying the concentration of perchlorate ion. We show an initially more ordered (α-helical) structure promotes peptide adsorption into the PEO layer. Further, a partially helical peptide undergoes an increase in helicity after entry, likely due to concomitant loss of capacity for peptide-solvent hydrogen bonding. Peptide interaction with the PEO chains resulted in entrapment and conformational change that was irreversible to elution with changing solution conditions in the case of the amphiphilic peptide. In contrast, the adsorption and conformational change of the non-amphiphilic peptide was reversible. These results indicate that responsive drug delivery systems based on peptide-loaded PEO layers can be controlled by modulation of solution conditions and peptide amphiphilicity.

Teaching engineering ethics using BLOCKS game

The aim of this study was to investigate the use of a newly developed design game called BLOCKS to stimulate awareness of ethical responsibilities amongst engineering students. The design game was played by seventeen teams of chemical engineering students, with each team having to arrange pieces of colored paper to produce two letters each. Before the end of the game, additional constraints were introduced to the teams such that they faced similar ambiguity in the technical facts that the engineers involved in the Challenger disaster had faced prior to the space shuttle launch. At this stage, the teams had to decide whether to continue with their original design or to develop alternative solutions. After the teams had made their decisions, a video of the Challenger explosion was shown followed by a post-game discussion. The students' opinion on five Statements on ethics was tracked via a Five-Item Likert survey which was administered three times, before and after the ethical scenario was introduced, and after the video and post-game discussion. The results from this study indicated that the combination of the game and the real-life incident from the video had generally strengthened the students' opinions of the Statements.

Biological accumulation of engineered nanomaterials: a review of current knowledge

Due to the widespread use of engineered nanomaterials (ENMs) in consumer and industrial products, concerns have been raised over their impacts once released into the ecosystems. While there has been a wealth of studies on the short-term acute toxic effects of ENMs over the past decade, work on the chronic endpoints, such as biological accumulation, has just begun to increase in last 2–3 years. Here, we comprehensively review over 65 papers on the biological accumulation of ENMs under a range of ecologically relevant exposure conditions in water, soil or sediment with the focus on quantitative comparison among these existing studies. We found that daphnid, fish, and earthworm are the most commonly studied ecological receptors. Current evidence suggests that ENM accumulation level is generally low in fish and earthworms with logarithmic bioconcentration concentration factor and biota-sediment accumulation factor ranging from 0.85–3.43 (L kg−1) and −2.21–0.4 (kg kg−1), respectively. ENMs accumulated in organisms at the lower trophic level can transfer to higher trophic level animals with the occurrence of biomagnification varying depending on the specific food chain studied. We conclude the review by identifying the challenges and knowledge gaps and propose paths forward.

Recent advances in benefits and hazards of engineered nanoparticles

Over recent decades, engineered nanoparticles are increasingly produced as the result of the rapid development in nanotechnology. They are currently used in a wide range of industrial and public sectors including healthcare, agriculture, transport, energy, materials, and information and communication technologies. As the result, an increasing concern has been raised over the potential impacts of engineered nanoparticles to human health. In the light of this, it is the purpose of the present review to discuss: (1) novel properties of engineered nanoparticles particularly in biomedical sciences, (2) most recently reported adverse effects of manufactured nanoparticles on human health and (3) different aspects of toxicological risk assessment of these nanoparticles.

On the way to the creation of next generation photoactive materials

INTRODUCTION

Transition from first- to second-generation photocatalysts has followed the notion that greater absorption of light in the visible region would yield greater spectral sensitivity and greater photoactivity. Though a promising strategy, in practice, it did not meet expectation because of various side issues, which in many cases has led to loss of photoactivity and chemical reactivity. This article examines some earlier notions that arose from applications of different metal oxides (e.g., TiO(2), ZnO, MgO among others) that made these oxides good photocatalysts in many processes.

DISCUSSION

Phenomena that proved relevant in developing next generation photoactive materials are considered: the dependence of the activity of photocatalysts on the band gap energy, the spectral variations of the activity of photoactive materials, and the spectral variations of selectivity of photoactive materials. The tendency to decrease the energy of actinic photons through doping in forming second-generation photocatalysts is completely opposite the fundamental observation in first-generation photocatalysts whereby the activity increased with increasing band gap energy. Extension of spectral sensitivity of second-generation photoactive materials also caused a decrease of their photoactivity; hence, some notions are reconsidered to produce next(third) generation photoactive materials. The article proposes the following concepts to develop next generation photocatalysts: (1) multi(two)-photon excitation of photoactive materials with lower energy photons to achieve the same excited state as with higher energy photons, (2) utilization of heterojunctions to drive electronic processes in the desired direction, and (3) selective photoexcitation of localized electronic states to gain better selectivity.

Polysaccharide films built by simultaneous or alternate spray: a rapid way to engineer biomaterial surfaces

We investigated polysaccharide films obtained by simultaneous and alternate spraying of a chitosan (CHI) solution as polycation and hyaluronic acid (HA), alginate (ALG), and chondroitin sulfate (CS) solutions as polyanions. For simultaneous spraying, the film thickness increases linearly with the cumulative spraying time and passes through a maximum for polyanion/CHI molar charge ratios lying between 0.6 and 1.2. The size of polyanion/CHI complexes formed in solution was compared with the simultaneously sprayed film growth rate as a function of the polyanion/CHI molar charge ratio. A good correlation was found. This suggests the importance of polyanion/polycation complexation in the simultaneous spraying process. Depending on the system, the film topography is either liquid-like or granular. Film biocompatibility was evaluated using human gingival fibroblasts. A small or no difference is observed in cell viability and adhesion between the two deposition processes. The CHI/HA system appears to be the best for cell adhesion inducing the clustering of CD44, a cell surface HA receptor, at the membrane of cells. Simultaneous or alternate spraying of CHI/HA appears thus to be a convenient and fast procedure for biomaterial surface modifications.

Gene expression of zebrafish embryos exposed to titanium dioxide nanoparticles and hydroxylated fullerenes

Increased release of engineered nanoparticles to the environment suggests a rising need for the monitoring and evaluation of potential toxicity. Zebrafish frequently have been used as a model species in human and aquatic toxicology studies. In this study, zebrafish embryos were microinjected in the otic vesicle with a sublethal dose of engineered nanoparticles (titanium dioxide/TiO(2) and hydroxylated fullerenes/C(60)(OH)(24)). A gene microarray analysis was performed on injected and control embryos to determine the potential for nanoparticles to change the expression of genes involved in cross talk of the nervous and immune systems. The exposure to TiO(2) and hydroxylated fullerenes caused shifts in gene regulation response patterns that were similar for downregulated genes but different for upregulated genes. Significant effects on gene regulation were observed on genes involved in circadian rhythm, kinase activity, vesicular transport and immune response. This is the first report of circadian rhythm gene deregulation by nanoparticles in aquatic animals, indicating the potential for broad physiological and behavioral effects controlled by the circadian system.

Diterpenoid biopolymers: new directions for renewable materials engineering

Most types of ambers are naturally occurring, relatively hard, durable resinite polymers derived from the exudates of trees. This resource has been coveted for thousands of years due to its numerous useful properties in industrial processes, beauty, and purported medicinal properties. Labdane diterpenoid-based ambers represent the most abundant and important resinites on earth. These resinites are a dwindling nonrenewable natural resource, so a new source of such materials needs to be established. Recent advances in sequencing technologies and biochemical engineering are rapidly accelerating the rate of identifying and assigning function to genes involved in terpenoid biosynthesis, as well as producing industrial-scale quantities of desired small-molecules in bacteria and yeast. This has provided new tools for engineering metabolic pathways capable of producing diterpenoid monomers that will enable the production of custom-tailored resinite-like polymers. Furthermore, this biosynthetic toolbox is continuously expanding, providing new possibilities for renewing dwindling stocks of naturally occurring resinite materials and engineering new materials for future applications.

Development of chemically engineered porous metal oxides for phosphate removal

In this study, the application of ordered mesoporous silica (OMS) doped with various metal oxides (Zr, Ti, Fe and Al) were studied for the removal of (ortho) phosphate ions from water by adsorption. The materials were characterized by means of N(2) physisorption (BET), powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM). The doped materials had surface areas between 600 and 700 m(2)g(-1) and exhibited pore sizes of 44-64 Å. Phosphate adsorption was determined by measurement of the aqueous concentration of orthophosphate using ultraviolet-visible (UV-vis) spectroscopy before and after extraction. The effects of different metal oxide loading ratios, initial concentration of phosphate solution, temperature and pH effects on the efficiency of phosphate removal were investigated. The doped mesoporous materials were effective adsorbents of orthophosphate and up to 100% removal was observed under appropriate conditions. 'Back extracting' the phosphate from the doped silica (following water treatment) was also investigated and shown to have little adverse effect on the adsorbent.

Discovery of a β-glucosidase inhibitor from a chemically engineered extract prepared through sulfonylation

A semisynthetic β-glucosidase inhibitor was identified from a chemically engineered extract prepared by reaction with benzenesulfonyl chloride. The structure includes a natural histamine portion and a benzenesulfonyl portion introduced during the diversification step.

Copper- and copper-N-heterocyclic carbene-catalyzed C-H activating carboxylation of terminal alkynes with CO2 at ambient conditions

The use of carbon dioxide as a renewable and environmentally friendly source of carbon in organic synthesis is a highly attractive approach, but its real world applications remain a great challenge. The major obstacles for commercialization of most current protocols are their low catalytic performances, harsh reaction conditions, and limited substrate scope. It is important to develop new reactions and new protocols for CO(2) transformations at mild conditions and in cost-efficient ways. Herein, a copper-catalyzed and copper-N-heterocyclic carbene-cocatalyzed transformation of CO(2) to carboxylic acids via C─H bond activation of terminal alkynes with or without base additives is reported. Various propiolic acids were synthesized in good to excellent yields under ambient conditions without consumption of any organometallic or organic reagent additives. This system has a wide scope of substrates and functional group tolerances and provides a powerful tool for the synthesis of highly functionalized propiolic acids. This catalytic system is a simple and economically viable protocol with great potential in practical applications.

Tuning the electrical properties of Si nanowire field-effect transistors by molecular engineering

Exposed facets of n-type silicon nanowires (Si NWs) fabricated by a top-down approach are successfully terminated with different organic functionalities, including 1,3-dioxan-2-ethyl, butyl, allyl, and propyl-alcohol, using a two-step chlorination/alkylation method. X-ray photoemission spectroscopy and spectroscopic ellipsometry establish the bonding and the coverage of these molecular layers. Field-effect transistors fabricated from these Si NWs displayed characteristics that depended critically on the type of molecular termination. Without molecules the source-drain conduction is unable to be turned off by negative gate voltages as large as -20 V. Upon adsorption of organic molecules there is an observed increase in the "on" current at large positive gate voltages and also a reduction, by several orders of magnitude, of the "off" current at large negative gate voltages. The zero-gate voltage transconductance of molecule-terminated Si NW correlates with the type of organic molecule. Adsorption of butyl and 1,3-dioxan-2-ethyl molecules improves the channel conductance over that of the original SiO(2)-Si NW, while adsorption of molecules with propyl-alcohol leads to a reduction. It is shown that a simple assumption based on the possible creation of surface states alongside the attachment of molecules may lead to a qualitative explanation of these electrical characteristics. The possibility and potential implications of modifying semiconductor devices by tuning the distribution of surface states via the functionality of attached molecules are discussed.