Molecular Engineering Approach Research Articles

Methoxydiphenylamine-substituted fluorene derivatives as hole transporting materials: role of molecular interaction on device photovoltaic performance

The molecular structure of the hole transporting material (HTM) play an important role in hole extraction in a perovskite solar cells. It has a significant influence on the molecular planarity, energy level, and charge transport properties. Understanding the relationship between the chemical structure of the HTM's and perovskite solar cells (PSCs) performance is crucial for the continued development of the efficient organic charge transporting materials. Using molecular engineering approach we have constructed a series of the hole transporting materials with strategically placed aliphatic substituents to investigate the relationship between the chemical structure of the HTMs and the photovoltaic performance. PSCs employing the investigated HTMs demonstrate power conversion efficiency values in the range of 9% to 16.8% highlighting the importance of the optimal molecular structure. An inappropriately placed side group could compromise the device performance. Due to the ease of synthesis and moieties employed in its construction, it offers a wide range of possible structural modifications. This class of molecules has a great potential for structural optimization in order to realize simple and efficient small molecule based HTMs for perovskite solar cells application.

Recent Updates on Molecular Genetic Engineering Approaches and Applications of Human Therapeutic Proteins

Therapeutic proteins are engineered proteins produced in the laboratory for pharmaceutical use. With the advent of recombinant DNA technology, the proteins can be generated in specific host cells under defined conditions. In the process of production of genetically engineered animals, the gene of interest can be added at a single cell stage to produce a cloned animal from genetically engineered cells. Several recombinant cytokines, clotting factors etc have been licensed and are currently being utilized for the treatment of cancer, infectious diseases, hemophilia, anemia, multiple sclerosis, and hepatitis B/C. Therapeutic proteins that are useful for human are successfully produced in poultry as well as in livestock animals. However, the fastest growing class of therapeutic proteins are antibodies especially monoclonal antibodies (mAb), the most important class of therapeutic protein with the potential to generate significant revolution in terms of clinical success rate. Here, we review the most recent clinical advances in the field of emerging and existing therapeutic proteins.

In Vitro Generated Hepatocyte-Like Cells: A Novel Tool in Regenerative Medicine and Drug Discovery.

Hepatocyte-like cells (HLCs) are generated from either various human pluripotent stem cells (hPSCs) including induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs), or direct cell conversion, mesenchymal stem cells as well as other stem cells like gestational tissues. They provide potential cell sources for biomedical applications. Liver transplantation is the gold standard treatment for the patients with end stage liver disease, but there are many obstacles limiting this process, like insufficient number of donated healthy livers. Meanwhile, the number of patients receiving a liver organ transplant for a better life is increasing. In this regard, HLCs may provide an adequate cell source to overcome these shortages. New molecular engineering approaches such as CRISPR/ Cas system applying in iPSCs technology provide the basic principles of gene correction for monogenic inherited metabolic liver diseases, as another application of HLCs. It has been shown that HLCs could replace primary human hepatocytes in drug discovery and hepatotoxicity tests. However, generation of fully functional HLCs is still a big challenge; several research groups have been trying to improve current differentiation protocols to achieve better HLCs according to morphology and function of cells. Large-scale generation of functional HLCs in bioreactors could make a new opportunity in producing enough hepatocytes for treating end-stage liver patients as well as other biomedical applications such as drug studies. In this review, regarding the biomedical value of HLCs, we focus on the current and efficient approaches for generating hepatocyte-like cells in vitro and discuss about their applications in regenerative medicine and drug discovery.

Molecular Engineering of Conus Peptides as Therapeutic Leads.

The venom from carnivorous marine snails of the Conus genus is a cocktail of peptides, proteins and small molecules that is used by the snail to capture prey. The peptides within this venom have been the focus of many drug design efforts as they exhibit potent and selective targeting of therapeutically important receptors, transporters and channels, particularly in relation to the treatment of chronic pain. The most well studied class of Conus peptides are the conotoxins, which are disulfide-rich and typically have well-defined three dimensional structures that are important for both biological activity and stability. In this chapter we discuss the molecular engineering approaches that have been used to modify these conotoxins to improve their pharmacological properties, including potency, selectivity, stability, and minimisation of the bioactive pharmacophore. These engineering strategies include sidechain modifications, disulfide substitution and deletion, backbone cyclisation, and truncations. Several of these re-engineered conotoxins have progressed to pre-clinical or clinical studies, which demonstrates the promise of using these molecular engineering techniques for the development of therapeutic leads.

Rational design and metabolic analysis of Escherichia coli for effective production of L-tryptophan at high concentration.

L-tryptophan (L-trp) is a biosynthetic precursor of various bioactive components with pharmaceutical interest. The development of an efficient L-trp production strain using targeted molecular engineering approaches is challenging due to the requirement of several precursors and the complex regulations of the pathways involved. In this study, we present a rationally engineered and genetically stable L-trp overproducing Escherichia coli strain. The streamlined strain E. coli S028 is able to efficiently produce 34-40g/L of L-trp with a yield of 0.15gL-trp/g glucose and a productivity of 0.60g/L/h in fed-batch fermentations. The titer and productivity of L-trp achieved are over twice as much as those reported so far for rationally developed L-trp producers. In addition, for the first time, both intracellular and extracellular concentrations of L-trp and the key metabolites in a L-trp hyperproducer strain were measured with an automated fast-sampling unit which is connected to a well-controlled bioreactor. The time series metabolic analysis gives valuable information about the regulation of L-trp synthesis in a highly productive strain and reveals targets for further improvement. Among others, it was found that L-trp and the byproduct glutamate (L-glu) accumulated to an extremely high level in the cell initially whereas the intracellular concentrations of glutamine (L-gln) stayed at a relatively low level throughout the fermentation. The metabolic analysis suggests that (a) the engineered serine biosynthesis pathway was able to effectively synthesize the substrate serine (intracellular concentration>8mM) for L-trp production, while (b) the substrate L-gln with an intracellular concentration of 0.8-1.2mM seems to limit the biosynthesis of L-trp, even though L-glu was overproduced intra- and extracellularly. Thus, an increased availability of glutamine synthetase which catalyzes L-glu conversion to L-gln and an overexpression of the L-trp exporter gene could be important targets for further strain improvement.

Integrated molecular and bioprocess engineering for bacterially produced immunogenic modular virus-like particle vaccine displaying 18 kDa rotavirus antigen.

A high global burden of rotavirus disease and the unresolved challenges with the marketed rotavirus vaccines, particularly in the developing world, have ignited efforts to develop virus-like particle (VLP) vaccines for rotavirus. While rotavirus-like particles comprising multiple viral proteins can be difficult to process, modular VLPs presenting rotavirus antigenic modules are promising alternatives in reducing process complexity and cost. In this study, integrated molecular and bioprocess engineering approaches were used to simplify the production of modular murine polyomavirus capsomeres and VLPs presenting a rotavirus 18 kDa VP8* antigen. A single construct was generated for dual expression of non-tagged murine polyomavirus capsid protein VP1 and modular VP1 inserted with VP8*, for co-expression in Escherichia coli. Co-expressed proteins assembled into pentameric capsomeres in E. coli. A selective salting-out precipitation and a polishing size exclusion chromatography step allowed the recovery of stable modular capsomeres from cell lysates at high purity, and modular capsomeres were successfully translated into modular VLPs when assembled in vitro. Immunogenicity study in mice showed that modular capsomeres and VLPs induced high levels of VP8*-specific antibodies. Our results demonstrate that a multipronged synthetic biology approach combining molecular and bioprocess engineering enabled simple and low-cost production of highly immunogenic modular capsomeres and VLPs presenting conformational VP8* antigenic modules. This strategy potentially provides a cost-effective production route for modular capsomere and VLP vaccines against rotavirus, highly suitable to manufacturing economics for the developing world. Biotechnol. Bioeng. 2017;114: 397-406. © 2016 Wiley Periodicals, Inc.

Molecular Engineering on Conjugated Side Chain for Polymer Solar Cells with Improved Efficiency and Accessibility

Recent advances in the power conversion efficiency (PCE) of polymer solar cells (PSCs) have demonstrated their potential for alternative photovoltaic technology. Besides photovoltaic performance, material cost and device fabrication process are among the key factors for practical applications. Herein, we report a facile molecular engineering approach with 4-methoxy modified thiophene as the conjugated side chain for polymer donors, which afforded lower highest occupied molecular orbital (HOMO) energy level and enhanced interchain interactions. Therefore, the corresponding PSCs exhibit enhanced open-circuit voltage and PCE compared with the counterparts with thiophene as the conjugated side chain. When fabricated from a nonhalogenated solvent without any additives, over 8% efficiency could be achieved in a representative polymer, PMOT5. Both the synthetic simplicity of materials and high performance from environmentally friendly solvent improve the accessibility of PSCs.

Engineering galectin-glycan interactions for immunotherapy and immunomodulation.

Galectins, a 15-member family of soluble carbohydrate-binding proteins, are receiving increasing interest as therapeutic targets for immunotherapy and immunomodulation due to their role as extracellular signals that regulate innate and adaptive immune cell phenotype and function. However, different galectins can have redundant, synergistic, or antagonistic signaling activity in normal immunological responses, such as resolution of inflammation and induction of antigen-specific tolerance. In addition, certain galectins can be hijacked to promote progression of immunopathologies, such as tumor immune privilege, metastasis, and viral infection, while others can inhibit these processes. Thus, eliciting a desired immunological outcome will likely necessitate therapeutics that can precisely enhance or inhibit particular galectin-glycan interactions. Multivalency is an important determinant of the affinity and specificity of natural galectin-glycan interactions, and is emerging as a key design element for therapeutics that can effectively manipulate galectin bioactivity. This minireview surveys current molecular and biomaterial engineering approaches to create therapeutics that can stabilize galectin multivalency or recapitulate natural glycan multivalency (i.e. "the glycocluster effect"). In particular, we highlight examples of using natural and engineered multivalent galectins for immunosuppression and immune tolerance, with a particular emphasis on treating autoimmune diseases or avoiding transplant rejection. In addition, we present examples of multivalent inhibitors of galectin-glycan interactions to maintain or restore T-cell function, with a particular emphasis on promoting antitumor immunity. Finally, we discuss emerging opportunities to further engineer galectin-glycan interactions for immunotherapy and immunomodulation.

Intraparticle Molecular Orbital Engineering of Semiconducting Polymer Nanoparticles as Amplified Theranostics for in Vivo Photoacoustic Imaging and Photothermal Therapy

Optical theranostic nanoagents that seamlessly and synergistically integrate light-generated signals with photothermal or photodynamic therapy can provide opportunities for cost-effective precision medicine, while the potential for clinical translation requires them to have good biocompatibility and high imaging/therapy performance. We herein report an intraparticle molecular orbital engineering approach to simultaneously enhance photoacoustic brightness and photothermal therapy efficacy of semiconducting polymer nanoparticles (SPNs) for in vivo imaging and treatment of cancer. The theranostic SPNs have a binary optical component nanostructure, wherein a near-infrared absorbing semiconducting polymer and an ultrasmall carbon dot (fullerene) interact with each other to induce photoinduced electron transfer upon light irradiation. Such an intraparticle optoelectronic interaction augments heat generation and consequently enhances the photoacoustic signal and maximum photothermal temperature of SPNs by 2.6- and 1.3-fold, respectively. With the use of the amplified SPN as the theranostic nanoagent, it permits enhanced photoacoustic imaging and photothermal ablation of tumor in living mice. Our study thus not only introduces a category of purely organic optical theranostics but also highlights a molecular guideline to amplify the effectiveness of light-intensive imaging and therapeutic nanosystems.

Plant synthetic biology for molecular engineering of signalling and development.

Molecular genetic studies of model plants in the past few decades have identified many key genes and pathways controlling development, metabolism and environmental responses. Recent technological and informatics advances have led to unprecedented volumes of data that may uncover underlying principles of plants as biological systems. The newly emerged discipline of synthetic biology and related molecular engineering approaches is built on this strong foundation. Today, plant regulatory pathways can be reconstituted in heterologous organisms to identify and manipulate parameters influencing signalling outputs. Moreover, regulatory circuits that include receptors, ligands, signal transduction components, epigenetic machinery and molecular motors can be engineered and introduced into plants to create novel traits in a predictive manner. Here, we provide a brief history of plant synthetic biology and significant recent examples of this approach, focusing on how knowledge generated by the reference plant Arabidopsis thaliana has contributed to the rapid rise of this new discipline, and discuss potential future directions.

Allele mining for resistance gene analogs (RGAs) in crop plants: A special emphasis on blast resistance in finger millet (Eleusine coracanaL.)

Finger millet a nutritionally rich underutilized crop requires more attention of research community. One of the major limitations of finger millet for wider agronomic acceptability is because of its susceptibility to blast fungus Magnaporthe grisea, which is also the causative agent of blast in rice. A large amount of sequence data available in the public domain has facilitated identification and isolation of novel genes for blast resistance and other agronomically important traits. Availability of such large genomic data has made allele mining a viable approach for detecting novel alleles for blast resistance in finger millet. However, very scarce genomic information is available in finger millet, being the major hurdle for such approaches. In the present review, we have summarized different strategic approaches suitable for allele mining of resistance gene analogs (RGAs) in finger millet by utilizing the large sequence data available for rice through comparative genomics. This paves the way for transfer of blast alleles into high yielding, blast susceptible and locally well adapted germplasm through molecular breeding and genetic engineering approaches.

Molecular Engineering: Transforming Benzophenoxazine Laser Dyes into Chromophores for Dye‐Sensitized Solar Cells: A Molecular Engineering Approach (Adv. Energy Mater. 9/2015)

Molecular Engineering: Transforming Benzophenoxazine Laser Dyes into Chromophores for Dye‐Sensitized Solar Cells: A Molecular Engineering Approach (Adv. Energy Mater. 9/2015)

Genetic Modification and High Expression of Cyclodextrin Glycosyltransferase

Cyclodextrin glycosyltransferase( CGTase,EC 2. 4. 1. 19) is an important enzyme with multiple functions,particularly the production of cyclodextrins( CD) and carbohydrate glycosylation. It is also applied in food industry. To modify the molecular structure of CGTase for improved performance in industrial applications,heterologous expression, site-directed mutagenesis and immobilization technology of cyclodextrin glycosyltransferase gene have been applied. Moreover,in recent years substantial progress has been made. In order to provide the reference in the related CGTase research,the heterologous expression strategies,the molecular engineering approaches,other technologies such as immobilized enzyme etc. were systematically summarized and discussed.

Transforming Benzophenoxazine Laser Dyes into Chromophores for Dye‐Sensitized Solar Cells: A Molecular Engineering Approach

The refunctionalization of a series of four well‐known industrial laser dyes, based on benzophenoxazine, is explored with the prospect of molecularly engineering new chromophores for dye‐sensitized solar cell (DSC) applications. Such engineering is important since a lack of suitable dyes is stifling the progress of DSC technology. The conceptual idea involves making laser dyes DSC‐active by chemical modification, while maintaining their key property attributes that are attractive to DSC applications. This molecular engineering follows a stepwise approach. First, molecular structures and optical absorption properties are determined for the parent laser dyes: Cresyl Violet (1), Oxazine 170 (2), Nile Blue A (3), Oxazine 750 (4). These reveal structure‐property relationships which define the prerequisites for computational molecular design of DSC dyes; the nature of their molecular architecture (D‐π‐A) and intramolecular charge transfer. Second, new DSC dyes are computationally designed by the in silico addition of a carboxylic acid anchor at various chemical substitution points in the parent laser dyes. A comparison of the resulting frontier molecular orbital energy levels with the conduction band edge of a TiO2 DSC photoanode and the redox potential of two electrolyte options I−/I3− and Co(II/III)tris(bipyridyl) suggests promise for these computationally designed dyes as co‐sensitizers for DSC applications.

Synthetic Biology: Computational Modeling Bridging the Gap between In Vitro and In Vivo Reactions

The synthetic biology firstly refers to the design and fabrication of biological components and systems that do not already exist in the natural world and to the redesign and fabrication of existing biological systems. The link of computational tools to cell-free systems, converts to synthetic biology is an emerging field expert to build artificial biological systems through the combination of molecular biology and engineering approaches. Herein, most findings describing the differences between in vivo and in vitro reactions and systems have been extensively described. The specific applications of computational tools to the design of an in vitro gene expression platform known as the artificial cell, its components and the strategies developed to predict activities of processor modules and to control the expression of genes have been discussed in detail. Potential applications of artificial cells in drug delivery, in biosynthesis, among others, have been described. Two sources of models for the possible developing of the computational toolbox for cell-free synthetic biology include: i) Physical models of single cellular components able to be created from original principles, guiding to focus on tools to predict structure and dynamics of particular components; ii) A wide-range of mathematical models for predicting system dynamics of natural cells. Regarding modeling algorithms, there is a broad kind of models available for synthetic biologists and some areas of potential growth identified for researchers interested in developing tools for cell-free systems. Among them, deterministic, exploratory, molecular dynamic, stochastic, all atom models, among others, have been described and discussed. By using computational models to set up quantitative differences between in vitro reactions and in vivo systems, could identify specific mechanisms in living organisms to be further used in in vitro reactions in order to facilitate their processes. Thus, computational modeling would bridge the gap between in vitro and in vivo reactions.

Engineered AAV vectors for improved central nervous system gene delivery.

Adeno-associated viruses (AAV) are non-pathogenic members of the Parvoviridae family that are being harnessed as delivery vehicles for both basic research and increasingly successful clinical gene therapy. To address a number of delivery shortcomings with natural AAV variants, we have developed and implemented directed evolution—a high-throughput molecular engineering approach to generate novel biomolecules with enhanced function—to create novel AAV vectors that are designed to preferentially transduce specific cell types in the central nervous system (CNS), including astrocytes, neural stem cells, and cells within the retina. These novel AAV vectors—which have enhanced infectivity in vitro and enhanced infectivity and selectivity in vivo—can enable more efficient studies to further our understanding of neurogenesis, development, aging, and disease. Furthermore, such engineered vectors may aid gene or cell replacement therapies to treat neurodegenerative disease or injury.

Cell-free expression of G-protein coupled receptors: new pipelines for challenging targets.

Based on their eminent importance for medical applications, G-protein coupled receptors are currently amongst the most frequently membrane protein targets analyzed by cell-free expression. The cell-free expression approach removes most bottlenecks known from conventional cell-based protein production pipelines and ensures fast access to a selected receptor target. In addition, receptors can be synthesized in presence of a large variety of artificial solubilization environments comprising detergents, lipids, nanodiscs and other amphiphilic compounds. The currently accumulated data based on a variety of analyzed receptors already opens promising perspectives for applications of cell-free synthesized samples in functional characterization and drug screening. Structural evaluation still suffers from high conformational dynamics causing sample instability and might be addressed in future by molecular engineering or immuno-stabilization approaches.

GMEnzy: a genetically modified enzybiotic database.

GMEs are genetically modified enzybiotics created through molecular engineering approaches to deal with the increasing problem of antibiotic resistance prevalence. We present a fully manually curated database, GMEnzy, which focuses on GMEs and their design strategies, production and purification methods, and biological activity data. GMEnzy collects and integrates all available GMEs and their related information into one web based database. Currently GMEnzy holds 186 GMEs from published literature. The GMEnzy interface is easy to use, and allows users to rapidly retrieve data according to desired search criteria. GMEnzy’s construction will increase the efficiency and convenience of improving these bioactive proteins for specific requirements, and will expand the arsenal available for researches to control drug-resistant pathogens. This database will prove valuable for researchers interested in genetically modified enzybiotics studies. GMEnzy is freely available on the Web at http://biotechlab.fudan.edu.cn/database/gmenzy/.

New molecular engineering approaches for crystallographic studies of large RNAs

Crystallization of RNAs with complex three-dimensional architectures remains a formidable experimental challenge. We review a number of successful heuristics involving engineering of the target RNAs to facilitate crystal contact formation, such as those that enabled the crystallization and structure determination of the cognate tRNA complexes of RNase P holoenzyme and the Stem I domain of the T-box riboswitch. Recently, RNA-targeted antibody Fab fragments and Kink-turn binding proteins have joined the ranks of successful chaperones for RNA crystallization. Lastly, we review the use of structured RNAs to facilitate crystallization of RNA-binding proteins and other RNAs.

Emerging molecular design strategies of unsymmetrical phthalocyanines for dye-sensitized solar cell applications

In recent years, dye-sensitized solar cells (DSSCs) have emerged as one of the possible solutions for the global energy crisis. Among the various components of DSSCs, the sensitizer, which harvests solar energy and injects electrons in to the semiconductor layer, plays a crucial role in achieving high efficiency and durability of the cell. To date ruthenium(II) sensitizers exhibit high efficiencies (>11.5%), but they are not so suitable for roof-top/commercial applications mainly because of their limited harvesting capability, expensive ruthenium metal and low durability. In this context, various sensitizers which include porphyrins, phthalocyanines and metal-free organic dye sensitizers have been developed and some of them were found to exhibit enhanced efficiencies compared to classical ruthenium(II) sensitizers. Man-made tetrapyrrolic systems, phthalocyanines (Pcs) have also been studied significantly because of their unique thermal and electronic properties in the red and near-IR regions. Over the years, the efficiency of Pc-based DSSC has improved to 6.1% by synthesizing various Pc derivatives and optimizing fabrication parameters. However, in the present review article, only the recent developments in Pc-based DSSCs have been documented in detail. This review also emphasizes different molecular engineering approaches that the researchers developed for achieving higher efficiency.