【最新中稿作品】纳米建筑学、仿生分层支架、微流控打印、蛋白质自组装等-科技论文配图-医学动画-动画宣传片-三维机械动画制作-北京中科幻彩

Abstract （上下滑动查看）

Engineering a proper immune response following biomaterial implantation is essential to bone tissue regeneration. Herein, a biomimetically hierarchical scaffold composed of deferoxamine@poly(ε-caprolactone) nanoparticles (DFO@PCL NPs), manganese carbonyl (MnCO) nanosheets, gelatin methacryloyl hydrogel, and a polylactide/hydroxyapatite (HA) matrix is fabricated to augment bone repair by facilitating the balance of the immune system and bone metabolism. First, a 3D printed stiff scaffold with a well-organized gradient structure mimics the cortical and cancellous bone tissues; meanwhile, an inside infusion of a soft hydrogel further endows the scaffold with characteristics of the extracellular matrix. A Fenton-like reaction between MnCO and endogenous hydrogen peroxide generated at the implant-tissue site triggers continuous release of carbon monoxide and Mn2+, thus significantly lessening inflammatory response by upregulating the M2 phenotype of macrophages, which also secretes vascular endothelial growth factor to induce vascular formation. Through activating the hypoxia-inducible factor-1α pathway, Mn2+ and DFO@PCL NP further promote angiogenesis. Moreover, DFO inhibits osteoclast differentiation and synergistically collaborates with the osteoinductive activity of HA. Based on amounts of data in vitro and in vivo, strong immunomodulatory, intensive angiogenic, weak osteoclastogenic, and superior osteogenic abilities of such an osteoimmunity-regulating scaffold present a profound effect on improving bone regeneration, which puts forward a worthy base and positive enlightenment for large-scale bone defect repair.

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Deoxyribonucleic acid (DNA) represents an important class of molecular building blocks for the assembly of supramolecular functional systems primarily due to its molecular recognition capability and sequence programmability. Eventually, DNA-based nanostructures are assembled in a way that their states remain at the thermodynamic minimum of the energy. However, active life-like functions and their interactive adaption require the integration of energy away from thermodynamic equilibrium. The construction of DNA-based artificial systems was often inspired by the naturally occurring dissipative assembly processes, which leads to the consumption of energy to maintain the thermodynamically non-equilibrium state. In this review, the recent progress of the fabrications and properties of DNA-based dissipative assembly systems toward nanoarchitectonics is summarized. It focuses on the principle of dissipative assembly and shows some pioneering examples of DNA-based dissipative assembly systems. The latest corresponding perspectives are also proposed.

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Protein networks can be assembled in vitro for basic biochemistry research, drug screening, and the creation of artificial cells. Two standard methodologies are used: manual pipetting and pipetting robots. Manual pipetting has limited throughput in the number of input reagents and the combination of reagents in a single sample. While pipetting robots are evident in improving pipetting efficiency and saving hands-on time, their liquid handling volume usually ranges from a few to hundreds of microliters. Microfluidic methods have been developed to minimize the reagent consumption and speed up screening but are challenging in multifactorial protein studies due to their reliance on complex structures and labeling dyes. Here, we engineered a new impact-printing-based methodology to generate printed microdroplet arrays containing water-in-oil droplets. The printed droplet volume was linearly proportional (R2 = 0.9999) to the single droplet number, and each single droplet volume was around 59.2 nL (coefficient of variation = 93.8%). Our new methodology enables the study of protein networks in both membrane-unbound and -bound states, without and with anchor lipids DGS–NTA(Ni), respectively. The methodology is demonstrated using a subnetwork of mitogen-activated protein kinase (MAPK). It takes less than 10 min to prepare 100 different droplet-based reactions, using <1 μL reaction volume at each reaction site. We validate the kinase (ATPase) activity of MEK1 (R4F)* and ERK2 WT individually and together under different concentrations, without and with the selective membrane attachment. Our new methodology provides a reagent-saving, efficient, and flexible way for protein network research and related applications.

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Covalent bonds and noncovalent interactions play crucial roles in enzyme self-assembly. Here, we designed a Tag/Catcher system named NGTag/NGCatcher in which the Catcher is a highly charged protein that can bind proteins with positively charged tails and rapidly form a stable isopeptide bond with NGTag. In this study, we present a multienzyme strategy based on covalent bonds and noncovalent interactions. In vitro, mCherry, YFP, and GFP can form protein-rich three-dimensional networks based on NGCatcher, NGTag, and RK (Arginine/Lysine) tails, respectively. Furthermore, this technology was applied to improve lycopene production in Escherichia coli. Three key enzymes were involved in lycopene production variants from Deinococcus wulumuqiensis R12 of NGCatcher_CrtE, NGTag_Idi, and RKIspARK, where the multienzyme complexes were clearly observed in vivo and in vitro, and the lycopene production in vivo was 17.8-fold higher than that in the control group. The NGTag/NGCatcher system will provide new opportunities for in vivo and in vitro multienzyme catalysis.

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Holographic technology shows great potential in data storage, three-dimensional display, and artificial intelligence, etc. The theoretical unbounded physical dimension of the orbital angular momentum (OAM) has been used as an information carrier in holography, resulting in the concept of OAM holography. However, the state of the illumination beam in the traditional holographic decoding process is based on phase modulation, resulting in a long switching time (generally no more than 30 Hz). The switching rate is physically determined by the switching speed of the illumination beam state. Currently, it is limited by the refresh rate of the phase-modulated spatial light modulator, which limits the future development of ultra-high-speed OAM-addressable dynamic holography.

This cover paper proposes a new concept of cross convolution aiming at high-speed extracting information from the OAM multiplexing hologram. They design a special amplitude-modulated pattern to illuminate the hologram in order to extract a specific picture based on the cross convolution relation between a series of spatial frequency components of the amplitude-modulated pattern and the OAM-multiplexing hologram in spatial frequency domain. With the help of the digital micromirror device, the amplitude-modulated pattern can be loaded and switched on the illumination beam at a frame rate of several kilohertz, so that holographic video can be played at this frame rate by using this technology which leads to a two-orders of magnitude increase of information extraction speed in OAM holography in principle. In their experiment, the significant digits of the value are encoded in the hologram, and they show that the first 100 significant digits are emerged quickly at a speed of 100 Hz as shown in the figure. The typical example of high-speed reconstruction of digits proves that the scheme can not only support holographic video, but also show the potential in construction of a high-capacity short-range optical communication system.