Stiffness-Transformable Nanoplatforms Responsive to the Tumor Microenvironment for Enhanced Tumor Therapeutic Efficacy.

Herein, we report, for the first time, a unique stiffness-transformable manganese oxide hybridized mesoporous organosilica nanoplatform (MMON) for enhancing tumor therapeutic efficacy. The prepared MMONs had a quasi-spherical morphology and were completely transformed into soft bowl-like nanocapsules in the simulated tumor microenvironment through the breakage of Mn-O bonds, which decreased their Young's modulus from 165.7 to 84.5 MPa. Due to their unique stiffness transformation properties, the MMONs had reduced macrophage internalization, improved tumor cell uptake, and enhanced penetration of multicellular spheroids. In addition, in vivo experiments showed that the MMONs displayed a 3.79- and 2.90-fold decrease in non-specific liver distribution and a 2.87- and 1.83-fold increase in tumor accumulation compared to their soft and stiff counterparts, respectively. Furthermore, chlorin e6 (Ce6) modified MMONs had significantly improved photodynamic therapeutic effect.

Intelligent Optimization of Tower Crane Location and Layout Based on Firefly Algorithm.

The existing tower crane positioning layout mainly depends on the experience of construction personnel, and the best tower crane positioning can be found through a large number of manual data calculation. This manual method is time-consuming and impractical. In view of this, aiming at the current situation that building information modeling (BIM) software can only obtain the relative coordinates of components, this article puts forward the key technology of importing computer-aided design (CAD) graphics into geographic information system (GIS) software to automatically obtain the world coordinate information. By clarifying the transfer relationship between the component material supply point, the component initial positioning point, and the tower crane optional positioning point, as well as the cooperative relationship between each positioning point and the tower crane operation, the tower crane positioning optimization model is formed, and the firefly algorithm is used to automatically calculate and generate the best positioning layout method of the tower crane on the project site. In this study, the vertical transportation and positioning of components are studied, and intelligent construction is formed by integrating information technology. It can further enrich the functions of perception, analysis, decision-making, and optimization; realize the decision-making intelligence of industrial buildings; and achieve the organic unity of engineering construction execution system and decision-making command system.

Isolation of functional bacterial strains from chromium-contaminated site and bioremediation potentials.

In this study, two Cr(VI)-reducing functional bacterial strains (TJ-1 and TJ-5) were successfully isolated and screened from the chromium-contaminated soil from a real site. The 16S rRNA gene sequences were analysed, which showed high similarity (>99%) with Stenotrophomonas maltophilia (TJ-1) and Brucella intermedius (TJ-5) species. The optimum growth for the two bacteria to reduce Cr(VI) were achieved at pH 7.0 and initial inoculation amount of 5%. The two strains were applied to real contaminated soil samples and showed better Cr removal when external carbon sources were added. Using sawdust as a solid-phase carbon source supplement, both TJ-1 and TJ-5 showed higher remediation efficiency (99.77% and 93.86%) than using glucose as the carbon source (68.56% and 70.87%). Results of the stability of soil Cr(VI) bioremediation revealed that the water-soluble Cr(VI) content of bioremediated sample remained unchanged, indicating that Cr(VI) is not easily released after death of the strains. Solid-phase carbon source supplements may help the cells to attach and grow into biofilms, creating a better growth condition which improved the remediation efficiency. Column experiments showed that the total remediation efficiencies by the two strains were 34.23% and 20.63%, respectively, within a short time period (76 h). Therefore, the two strains showed great bioremediation potentials for chromium-contaminated sites and can be used in future application of in-situ bioremediation.

Astral hydrogels mimic tissue mechanics by aster-aster interpenetration.

Many soft tissues are compression-stiffening and extension-softening in response to axial strains, but common hydrogels are either inert (for ideal chains) or tissue-opposite (for semiflexible polymers). Herein, we report a class of astral hydrogels that are structurally distinct from tissues but mechanically tissue-like. Specifically, hierarchical self-assembly of amphiphilic gemini molecules produces radial asters with a common core and divergently growing, semiflexible ribbons; adjacent asters moderately interpenetrate each other via interlacement of their peripheral ribbons to form a gel network. Resembling tissues, the astral gels stiffen in compression and soften in extension with all the experimental data across different gel compositions collapsing onto a single master curve. We put forward a minimal model to reproduce the master curve quantitatively, underlying the determinant role of aster-aster interpenetration. Compression significantly expands the interpenetration region, during which the number of effective crosslinks is increased and the network strengthened, while extension does the opposite. Looking forward, we expect this unique mechanism of interpenetration to provide a fresh perspective for designing and constructing mechanically tissue-like materials.

Smart Adhesive Peptide Nanofibers for Cell Capture and Release.

Efficient cell capture and release methods are important for single-cell analysis of pathological samples. It requires not only strong cell binding but also mild cell release to maximize the number of collected cells while maintaining their viability. Here, we report a smart cell capture and release system based on self-assembling adhesive peptide nanofibers. We installed a versatile surface binding motif, 3, 4-dihydroxyphenylalanine to the C-terminus of a self-assembling peptide. We show that the designed peptide can self-assemble at physiological pH to establish strong cell and substrate binding. The binding strength is dramatically reduced upon the dissembling of the peptide fibers triggered by raising the pH to slightly basic. We demonstrate the efficient capture of four different cells using this system. The capture rates are comparable to fibrin glue and the released cells retain higher viability than those released by enzymatic digestion approaches. Given that this method is highly efficient, biocompatible, and easy to implement, we anticipate that this approach can be widely applied to cell capture and release for single cell analysis and cell therapy.

Synthetic asters as elastic and radial skeletons.

The radial geometry with rays radiated from a common core occurs ubiquitously in nature for its symmetry and functions. Herein, we report a class of synthetic asters with well-defined core-ray geometry that can function as elastic and radial skeletons to harbor nano- and microparticles. We fabricate the asters in a single, facile, and high-yield step that can be readily scaled up; specifically, amphiphilic gemini molecules self-assemble in water into asters with an amorphous core and divergently growing, twisted crystalline ribbons. The asters can spontaneously position microparticles in the cores, along the radial ribbons, or by the outer rims depending on particle sizes and surface chemistry. Their mechanical properties are determined on single- and multiple-aster levels. We further maneuver the synthetic asters as building blocks to form higher-order structures in virtue of aster-aster adhesion induced by ribbon intertwining. We envision the astral structures to act as rudimentary spatial organizers in nanoscience for coordinated multicomponent systems, possibly leading to emergent, synergistic functions.

Engineered Recombinant Proteins for Aqueous Ultrasonic Exfoliation and Dispersion of Biofunctionalized 2D Materials.

Aqueous ultrasonic exfoliation by using proteins as dispersants allows for the simultaneous production and biofunctionalization of single- or few-layered 2D materials for biomedical applications. However, the production yield and quality are always a concern. Here, the production of stable, low-defect, and biofunctionalized 2D flakes of graphene by using bifunctional chimeric polyproteins as dispersants is shown. The chimeric polyproteins contain an amphiphilic protein, hydrophobin (HFBI), to serve as the anchoring point that strongly binds to graphene layers and tandem repeats of a globular protein, GB1, to respond and transmit the ultrasonic force for efficient mechanical exfoliation. For this reason, the production yield is much higher than those obtained by using HFBI alone. Moreover, the yield, lateral size and number of layers can be fine-tuned by the number of GB1 repeats. Other 2D materials, such as MoS2 and WS2 , can also be exfoliated in the same manner, demonstrating the versatility of this approach.

Correction: A pH responsive AIE probe for enzyme assays.

Correction for 'A pH responsive AIE probe for enzyme assays' by Leilei Shi et al., Analyst, 2018, DOI: 10.1039/c7an01710c.

A pH responsive AIE probe for enzyme assays.

By combining leucine (Leu) and tetraphenylethene (TPE), a pH-sensitive aggregation induced emission (AIE) probe TPE-Leu was developed. The aliphatic amine in TPE-Leu was more easily protonated under acidic conditions, which made TPE-Leu more water soluble. Therefore, the protonated AIE probe showed weak fluorescence under acidic conditions. When the pH was changed to basic conditions, it showed strong fluorescence due to the hydrophobic nature of TPE-Leu. We demonstrated that the probe showed high selectivity toward pH changes with the coexistence of other potential species such as metal ions, redox agents, and biomolecules. In contrast, TPE-NH2 did not exhibit obvious pH-sensitive properties. Moreover, TPE-Leu was further utilized to develop a sensitive and selective sensing platform for urease and acetylcholinesterase (AChE) detection. The current study not only provides a new strategy for designing pH-sensitive fluorescent probes for bioassays but also broadens the applications of AIE probes.

Single-molecule study of the synergistic effects of positive charges and Dopa for wet adhesion.

Using AFM based single-molecule force spectroscopy, we studied the synergy between Dopa and lysine for wet adhesion on titania (TiO2) and mica surfaces. We found that the binding forces for lysine-Dopa dipeptides are significantly higher when the positive charge of lysine is unprotected on both surfaces. However, such a synergistic effect is absent when the sequence is reversed. We attribute such differential synergistic effects to their distinct structure for load distribution within the molecules, which may represent a general principle for synergistic strong adhesion.

Single-Molecule Force Spectroscopy Reveals Multiple Binding Modes between DOPA and Different Rutile Surfaces.

Inspired by marine mussel adhesive systems, numerous 3,4-dihydroxyphenylalanine (DOPA)-containing surface coating materials have been recently designed. It is well known that DOPA has a strong adhesion ability to different kinds of wet surfaces. However, the molecular mechanism of DOPA adhesion remains elusive. Recent biophysical studies of DOPA adhesion by both surface force apparatus (SFA) and atomic force microscopy (AFM) suggest that DOPA can bind to a wide range of surfaces exhibiting diverse chemical properties through different binding mechanisms. Here, using AFM-based single-molecule force spectroscopy, we show that even for chemically well-defined crystal surfaces, DOPA can bind to them by multiple binding modes. The binding forces between DOPA and different rutile TiO2 surfaces can vary within a broad range from 40-800 pN at a pulling speed of 1000 nm s-1 and are largely dependent on the surface properties. Our findings indicate that the local chemical environment can greatly affect DOPA adhesion, and that single-molecule force spectroscopy is a unique tool to reveal the heterogeneity of DOPA adhesion to the same surface.