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T cell-derived small extracellular vesicles (sEVs) exhibit anti-cancer effects. However, their anti-cancer potential should be reinforced to enhance clinical applicability. Herein, we generated interleukin-2-tethered sEVs (IL2-sEVs) from engineered Jurkat T cells expressing IL2 at the plasma membrane via a flexible linker to induce an autocrine effect. IL2-sEVs increased the anti-cancer ability of CD8

Transcriptional regulator proteins are closely involved in essential survival strategies in bacteria. AcrR is a one-component allosteric repressor of the genes associated with lipid transport and antibiotic resistance. When fatty acid ligands bind to the C-terminal ligand-binding cavity of AcrR, a conformational change in the N-terminal operator-binding region of AcrR is triggered, which releases the repressed DNA and initiates transcription. This paper focuses on the structural transition mechanism of AcrR of Mycobacterium tuberculosis upon DNA and ligand binding. AcrR loses its structural integrity upon ligand-mediated structural alteration and bends toward the promoter DNA in a more compact form, initiating a rotational motion. Our functional characterization of AcrR and description of the ligand- and DNA-recognition mechanism may facilitate the discovery of new therapies for tuberculosis.

A cytocompatible method of surface-initiated, activator regenerated by electron transfer, atom transfer radical polymerization (SI-ARGET ATRP) is developed for engineering cell surfaces with synthetic polymers. Dopamine-based ATRP initiators are used for both introducing the ATRP initiator onto chemically complex cell surfaces uniformly (by the material-independent coating property of polydopamine) and protecting the cells from radical attack during polymerization (by the radical-scavenging property of polydopamine). Synthetic polymers are grafted onto the surface of individual yeast cells without significant loss of cell viability, and the uniform and dense grafting is confirmed by various characterization methods including agglutination assay and cell-division studies. This work will provide a strategic approach to the generation of living cell-polymer hybrid structures and open the door to their application in multitude of areas, such as sensor technology, catalysis, theranostics, and cell therapy.

The exceptional mechanical properties of the byssus—the fibrous holdfast of mussels that provides underwater adhesion—have potential applications in medicine and technology. The catechol–Fe3+–catechol interaction underlies the unique properties of mussel byssus and has emerged as a tool for developing functional hybrid materials such as pH-responsive, self-healing gels. Herein, the construction of functional alginate (Alg) film on a solid substrate inspired by mussel byssus is reported. The approach consists of spin-coating-assisted deposition of Alg catechols onto a solid substrate and their subsequent crosslinking via catechol–Fe3+–catechol interactions. This yields robust and multilayered Alg films that are resistant to protein adsorption and suppress bacterial adhesion. This method can be used to create antibacterial films for coating implanted medical devices.

Three-dimensional (3D) in vitro model systems such as spheroids and organoids provide an opportunity to extend our physiological understanding using recapitulated tissues that mimic physiological characteristics of in vivo microenvironments. Unlike two-dimensional (2D) systems, 3D in vitro systems can bridge the gap between inadequate 2D cultures and the in vivo environments, providing novel insights on complex physiological mechanisms at various scales of organization, ranging from the cellular, tissue-, to organ-levels. To satisfy the ever-increasing need for highly complex and sophisticated systems, many 3D in vitro models with advanced microengineering techniques have been developed to answer diverse physiological questions. This review summarizes recent advances in engineered microsystems for the development of 3D in vitro model systems. We highlight and discuss in detail the relationship between the underlying physics behind the microengineering techniques, and their ability to recapitulate distinct 3D cellular structures and functions of diverse types of tissues and organs. We also introduce a number of 3D in vitro models and their engineering principles. Finally, we summarize current limitations, and provide perspectives for future directions in guiding the development of 3D in vitro model systems using microengineering techniques.

Controllable generation of complex emulsions comprising exceptional features such as several compartments and shape anisotropy is becoming increasingly important. Complex emulsions are attracting great interest due to their significant potential in many applications, including foods, pharmaceuticals, cosmetics, materials, and chemical separations. Microfluidics is emerging as a promising route to the generation of complex emulsions, providing precise control over emulsion shape, size, and compartments. The aim of this Minireview is to mainly describe the progress of microfluidic approaches to design complex emulsions using hydrodynamic control and phase separation. The emulsions formed are classified according to their morphology, anisotropy, and internal structure. Emerging applications of complex emulsions formed using these microfluidic techniques are discussed.

The protective coating on mussel (Mytilus galloprovincialis) byssus has attracted considerable research interest because of its excellent mechanical properties such as hardness and extensibility. These special properties are known to be highly related with specific interactions between mussel foot protein-1 and metal ions. In particular, the complexation between catechols in mfp-1 and iron(III) has been identified as a key interaction. This finding has given opportunities for pursuing promising applications. Herein, we report that emulating the properties of the mussel byssus cuticle provides an important platform for developing reversible layer-by-layer (LbL) deposition, an advanced technique for surface modification. LbL films were constructed on solid substrates by sequential immersion of substrates into solutions containing iron(III) and catecholic compounds. The thickness of the LbL films was effectively controlled by increasing the immersion steps, and the reversibility of the LbL deposition was demonstrated by addition of a chelating agent.

In tissue engineering, fabrication of 3D scaffolds with well-defined, inter-connected pores followed by culture of mammalian cells is a typical approach. In practice, however, hydrophobicity of scaffold surfaces is not suitable for cells to be adhered because of poor wettability. Especially, infiltration followed by adhesion of cells inside hydrophobic scaffolds remains as a challenge. Thus, hydrophilic conversions of the surfaces regardless of surface location are critical for success. Herein, a method to enhance infiltration and adhesion of preosteoblasts inside hydrophobic poly(ϵ-caprolactone) (PCL) scaffolds by a bio-inspired, hydroxyapatite formation is demonstrated. The approach can be a general method for controlling hydrophilicity of inner surfaces of scaffolds.

Surface modification is one of the most important techniques in modern science and engineering. The facile introduction of a wide variety of desired properties onto virtually any material surface is an ultimate goal in surface chemistry. To achieve this goal, the incorporation of structurally diverse molecules onto any material surface is an essential capability for ideal surface modification. Here, a general strategy for surface modification is presented in which many diverse surfaces can be functionalized by immobilizing a wide variety of molecules. This strategy functionalizes surfaces by a one-step immersion of substrates in a one-pot mixture of a molecule and a catecholamine surface modification agent. This one-step procedure for surface modification represents a standard protocol to control interfacial properties., Armed Forces Institute of Regenerative Medicine (Award W81XWH-08-2-0034), National Institutes of Health (U.S.) (2R01DE016516-06)

We investigated the formation of thermoresponsive gold nanoparticle/poly(N-isopropylacrylamde) (AuNP/ PNIPAAm) core/shell hybrid structures by surface-initiated, atom transfer radical polymerization (SI-ATRP) in aqueous media and the effect of cross-linking on the thermoresponsiveness of the AuNP/PNIPAAm hybrids. The disulfide containing an ATRP initiator was attached onto AuNPs and the monomer, NIPAAm, was polymerized from the surface of AuNPs in the absence or presence of a cross-linker, ethylene diacrylate, in aqueous media at room temperature. The resulting brush-type and cross-linked AuNP/PNIPAAm hybrids were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and variable temperature dynamic light scattering.

Since the pioneering work by Whitesides, innumerable platforms that aim to spatio-selectively seed cells and control the degree of cell-cell interactions in vitro have been developed. These methods, however, have generally been technically and methodologically complex, or demanded stringent materials and conditions. In this work, we introduce zwitterionic lipids as patternable, cell-repellant masks for selectively seeding cells. The lipid masks are easily removed with a routine washing step under physiological conditions (37 °C, pH 7.4), and are used to create patterned cocultures, as well as to conduct cell migration studies. We demonstrate, via patterned cocultures of NIH 3T3 fibroblasts and HeLa cells, that HeLa cells proliferate far more aggressively than NIH 3T3 cells, regardless of initial population sizes. We also show that fibronectin-coated substrates induce cell movement akin to collective migration in NIH 3T3 fibroblasts, while the cells cultured on unmodified substrates migrate independently. Our lipid mask platform offers a rapid and highly biocompatible means of selectively seeding cells, and acts as a versatile tool for the study of cell-cell interactions.

Gold(III) chloride was found to be a highly efficient catalyst for the cyanosilylation of various ketones and aldehydes. The reactions were complete within 30 minutes at room temperature in the presence of only one mol% gold(III) chloride, yielding the corresponding cyanohydrin trimethylsilyl ethers in very good yields. The isolated yields for the reactions of ketones were up to 98%, and the reactions of aldehydes gave 100% conversion, as monitored by 1 H NMR spectroscopy.

However, functionalizing surfaces in a material-independent manner was not demonstrated, and the oxidation chemistry of the polyphenols was not investi-gated at a molecular level due to the well-known complexity of crosslinking chemistry. Herein, we report that a plant-inspired, amine-containing small molecule called 5-pyrogallol 2-aminoethane (PAE) can perform surface functionalization in a material-independent manner. The presence of primary amine and pyrogallol moie-ties are essential for the material-independent coating ability of PAE compared to other compounds with the pyrogallol group. The PAE-functionalized surfaces are multifunctional in that they are able to trigger ring-opening polymerization, form a gold nanoshell adsorbing near infrared spectrum, and maintain long-lasting hydrophilicity on poly(dimethylsiloxane) (PDMS) surfaces. The multi-functionality of the PAE-mediated surface chemistry will be useful in many areas, such as medical device development, drug delivery, mammalian cell culture, and the development of energy storage devices.