Fengjiao Lyu

Bio: Fengjiao Lyu is an academic researcher from Stanford University. The author has contributed to research in topics: Pickering emulsion & Population. The author has an hindex of 7, co-authored 12 publications receiving 722 citations. Previous affiliations of Fengjiao Lyu include Tsinghua University.

One-Pot Synthesis of Protein-Embedded Metal–Organic Frameworks with Enhanced Biological Activities

Abstract: Protein molecules were directly embedded in metal–organic frameworks (MOFs) by a coprecipitation method. The protein molecules majorly embedded on the surface region of MOFs display high biological activities. As a demonstration of the power of such materials, the resulting Cyt c embedded in ZIF-8 showed a 10-fold increase in peroxidase activity compared to free Cyt c in solution and thus gave convenient, fast, and highly sensitive detection of trace amounts of explosive organic peroxides in solution.

Phenotyping antibiotic resistance with single-cell resolution for the detection of heteroresistance

Abstract: Antibiotic resistance has emerged as an imminent threat to public health. It is also increasingly recognized to be a heterogeneous phenomenon: a population of bacteria, found in vivo or in vitro, often consists of a mixture of cells that have different degrees of resistance to antibiotics. The conventional metric to measure antibiotic resistance based on an ensemble-average minimum inhibitory concentration (MIC) fails to characterize the heterogeneity present within a bacterial population. This work describes a droplet microfluidics method to encapsulate single cells from a population consisting of a mixture of antibiotic-sensitive and antibiotic-resistant bacteria. Co-encapsulating viability probe alamarBlue with the cells allows the use of fluorescent drops as a read-out for drops that contain live cells after their exposure to antibiotics. Enumerating the fluorescent drops thus gives the number of resistant cells in the population. Our method enables the quantitative phenotyping of heterogeneous resistance, or heteroresistance, with single-cell resolution. We show that it is possible to detect a resistant sub-population that comprises as low as 10−6 of the entire population of cells. Such high resolution further allows us to measure the evolution of heteroresistance arising from the exposure of a homogeneous isogenic culture of susceptible cells to sub-lethal dosages of antibiotics. We demonstrate an application of this system to characterize genetic determinants of antimicrobial resistance emergence. The high resolution of phenotypic detection and quantification of minority variants demonstrated in this work has the potential to facilitate the elucidation of the mechanisms underlying heteroresistance. Such understanding will in turn inform the best practices for antibiotic use and containment of antimicrobial resistance in a wide range of settings from agriculture and aquaculture to disease management. Clinically, the ability to quantify and track the composition of a bacterial population will benefit the decision-making process in both the diagnosis and the treatment of bacterial infections, and will ultimately improve patient outcome and avert the spread of resistant populations.

Fluorinated Pickering Emulsions with Nonadsorbing Interfaces for Droplet-based Enzymatic Assays

Abstract: This work describes the use of fluorinated Pickering emulsions with nonadsorbing interfaces in droplet-based enzymatic assays State-of-the-art droplet assays have relied on one type of surfactants consisting of perfluorinated polyether and polyethylene glycol (PFPE-PEG) These surfactants are known to have limitations including the tedious synthesis and interdrop molecular transport which leads to the cross-contamination of droplet contents Previously we have shown that replacing surfactants with nanoparticles as droplet stabilizers mitigate interdrop transport of small molecules The nonspecific adsorption of enzymes on nanoparticle surface, however, could cause structural changes in enzymes and consequently the loss of enzymatic activity To overcome such challenge, we render nanoparticle surface nonadsorbing to enzymes by in situ adsorption of polyethylene glycol (PEG) on particle surfaces We show that enzyme activities are preserved in droplets stabilized by PEG-adsorbed nanoparticles, and are comparable with those in drops stabilized by PFPE-PEG surfactants In addition, our nonadsorbing Pickering emulsions successfully prevent interdrop molecular transport, thereby maintaining the accuracy of droplet assays The particles are also simple and economical to synthesize The PEG-adsorbed nanoparticles described in this work are thus a competitive alternative to the current surfactant system, and can potentially enable new droplet-based biochemical assays

Protein and metal organic skeleton compound composite material and preparation method thereof

Abstract: The invention discloses a protein and metal organic skeleton compound composite material and a preparation method thereof. The preparation method of the protein and metal organic skeleton compound composite material comprises the step of carrying out reaction on protein, zinc ions and an organic ligand in a solvent, so that the protein and metal organic skeleton compound composite material is obtained, wherein the organic ligand is any one of 2-methylimidazole, benzimidazole and imidazole. The preparation method of the protein and metal organic skeleton compound composite material is simple in operation and mild in conditions, the obtained protein and metal organic skeleton compound composite material product is high in protein embedding rate, and the required drugs are easily available; the biological composite material, namely the protein and metal organic skeleton compound composite material, has the advantages of high porosity, large specific surface area, good stability, good catalytic activity and the like; after protein is compounded with a metal organic skeleton material, the stability of the protein is improved, and the catalytic activity of the protein is improved or maintained in a greater degree.

Metal–organic frameworks meet metal nanoparticles: synergistic effect for enhanced catalysis

Abstract: Metal–organic frameworks (MOFs), established as a relatively new class of crystalline porous materials with high surface area, structural diversity, and tailorability, attract extensive interest and exhibit a variety of applications, especially in catalysis. Their permanent porosity enables their inherent superiority in confining guest species, particularly small metal nanoparticles (MNPs), for improved catalytic performance and/or the expansion of reaction scope. This is a rapidly developing interdisciplinary research field. In this review, we provide an overview of significant progress in the development of MNP/MOF composites, including various preparation strategies and characterization methods as well as catalytic applications. Special emphasis is placed on synergistic effects between the two components that result in an enhanced performance in heterogeneous catalysis. Finally, the prospects of MNP/MOF composites in catalysis and remaining issues in this field have been indicated.

Biomimetic mineralization of metal-organic frameworks as protective coatings for biomacromolecules.

Abstract: Robust biomacromolecules could be used for a wide range of biotechnological applications. Here the authors report a biomimetic mineralization process, in which biomolecules are encapsulated within metal-organic frameworks, and their stability is subsequently increased without significant bioactivity loss.

One-pot Synthesis of Metal-Organic Frameworks with Encapsulated Target Molecules and Their Applications for Controlled Drug Delivery.

Abstract: Many medical and chemical applications require target molecules to be delivered in a controlled manner at precise locations. Metal-organic frameworks (MOFs) have high porosity, large surface area, and tunable functionality and are promising carriers for such purposes. Current approaches for incorporating target molecules are based on multistep postfunctionalization. Here, we report a novel approach that combines MOF synthesis and molecule encapsulation in a one-pot process. We demonstrate that large drug and dye molecules can be encapsulated in zeolitic imidazolate framework (ZIF) crystals. The molecules are homogeneously distributed within the crystals, and their loadings can be tuned. We show that ZIF-8 crystals loaded with the anticancer drug doxorubicin (DOX) are efficient drug delivery vehicles in cancer therapy using pH-responsive release. Their efficacy on breast cancer cell lines is higher than that of free DOX. Our one-pot process opens new possibilities to construct multifunctional delivery systems for a wide range of applications.

Enzyme–MOF (metal–organic framework) composites

Abstract: The ex vivo application of enzymes in various processes, especially via enzyme immobilization techniques, has been extensively studied in recent years in order to enhance the recyclability of enzymes, to minimize enzyme contamination in the product, and to explore novel horizons for enzymes in biomedical applications. Possessing remarkable amenability in structural design of the frameworks as well as almost unparalelled surface tunability, Metal–Organic Frameworks (MOFs) have been gaining popularity as candidates for enzyme immobilization platforms. Many MOF–enzyme composites have achieved unprecedented results, far outperforming free enzymes in many aspects. This review summarizes recent developments of MOF–enzyme composites with special emphasis on preparative techniques and the synergistic effects of enzymes and MOFs. The applications of MOF–enzyme composites, primarily in transferation, catalysis and sensing, are presented as well. The enhancement of enzymatic activity of the composites over free enzymes in biologically incompatible conditions is emphasized in many cases.

From fundamentals to applications: a toolbox for robust and multifunctional MOF materials.

Abstract: In recent years, metal-organic frameworks (MOFs) have been regarded as one of the most important classes of materials The combination of various metal clusters and ligands, arranged in a vast array of geometries has led to an ever-expanding MOF family Each year, new and novel MOF structures are discovered The structural diversity present in MOFs has significantly expanded the application of these new materials MOFs show great potential for a variety of applications, including but not limited to: gas storage and separation, catalysis, biomedicine delivery, and chemical sensing This review intends to offer a short summary of some of the most important topics and recent development in MOFs The scope of this review shall cover the fundamental aspects concerning the design and synthesis of MOFs and range to the practical applications regarding their stability and derivative structures Emerging trends of MOF development will also be discussed These trends shall include multicomponent MOFs, defect development in MOFs, and MOF composites The ever important structure-property-application relationship for MOFs will also be investigated Overall, this review provides insight into both existing structures and emerging aspects of MOFs