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Wrinkles are often found to have a strong influence on the properties of nanomaterials and have attracted extensive research interest. However, the consequences of the use of wrinkled nanomaterials in biological systems remain largely unknown. Here, using molecular dynamics simulations, we studied the interactions of a wrinkled graphene with proteins, using the villin headpiece (HP35) as the representative model. Our results clearly revealed that the wrinkle, especially the wrinkle corner, showed stronger binding affinity to HP35 than the planar surface where HP35 experienced accelerated and more severe unfolding. This is because the transverse translocation of the aromatic residues of the protein is highly confined at the wrinkle corner. The movement of other parts of the protein causes unfolding of the protein secondary structure and releases hydrophobic residues to bind to graphene, causing complete denaturation. Further free energy analyses revealed that this is attributed to the stronger binding affinity of residues to the wrinkle corner than to the planar surface. The present findings provide a deeper understanding of the effect of graphene wrinkles on protein stability. This finding may be generalized to other types of biomolecules and may also guide the design of biomedical nanomaterials through surface structural engineering.

Direct removal of 99TcO4- from alkaline nuclear waste is desirable because of the nuclear waste management and environmental protection relevant to nuclear energy but is yet to be achieved given that combined features of decent base-resistance and high uptake selectivity toward anions with low charge density have not been integrated into a single anion-exchange material. Herein, we proposed a strategy overcoming these challenges by rationally modifying the imidazolium unit of a cationic polymeric network (SCU-CPN-4) with bulky alkyl groups avoiding its ring-opening reaction induced by OH- because of the steric hindrance effect. This significantly improves not only the base-resistance but also the affinity toward TcO4- as a result of enhanced hydrophobicity, compared to other existing anion-exchange materials. More importantly, SCU-CPN-4 exhibits record high uptake selectivity, fast sorption kinetics, sufficient robustness, and promising reusability for removing 99TcO4- from the simulated high-level waste stream at the U.S. Savannah River Site, a typical alkaline nuclear waste, in both batch experiment and dynamic column separation test for the first time.

For exploring new natural product-based leading compounds with antifungal activity, 15 novel 3-carene-derived 4-substituted phenyl-1,2,4-triazolinthiones 7a∼7o bearing gem-dimethylcyclopropane moiety were synthesized and structurally characterized by UV/VIS, FT-IR

In search of novel bioactive compounds with excellent and broad-spectrum antifungal activity and nanopesticides with sustained releasing property, a series of novel myrtenal-based diacylhydrazines were designed, synthesized, and characterized. The preliminary bioassay showed that myrtenal-based 2-picolinyl hydrazide exhibited better or comparable antifungal activity than that of the commercial fungicides boscalid and chlorothalonil against the tested fungi. Furthermore, myrtenal-based nanocellulose was designed as a nanopesticide carrier and prepared from two biomass materials, bleached bagasse pulp and turpentine oil. Drug-loading capacities (LCs) of these carriers and sustained releasing properties of corresponding complexes were also evaluated, and the results indicated that the esterification reaction in the different solvents would affect the micromorphology of carriers, which was the important influential factor for loading or releasing drugs. To our delight, complex VIII-3 (LC = 0.32, total releasing amount/time = 99.8%/168 h) showed a macroporous framework with the drug evenly distributed across the opening network and staged drug-releasing performance that deserved further study as a nanopesticide.

Cytochrome bc1 complex is an important component of cellular respiratory chain, and it is also an important target enzyme to inhibit the growth of plant pathogens. Using cytochrome bc1 complex as the target enzyme, twenty-three novel nopol-based 1,2,4-triazole-thioether compounds were designed and synthesized from natural preponderant resource β-pinene, and their structures were confirmed by FT-IR, NMR, ESI-MS and elemental analysis. The in vitro antifungal activity of the target compounds 5a-5w was preliminarily evaluated against eight plant pathogens at the concentration of 50 µg/ml. The bioassay results showed that the target compounds exhibited the best antifungal activity against Physalospora piricola, in which compounds 5b (R= o-CH3 Ph), 5e (R= o-OCH3 Ph), 5h (R= o-F Ph), 5m (R= o-Br Ph), 5o (R= m,m-OCH3 Ph), and 5r (R= p-OH Ph) had inhibition rates of 91.4, 83.3, 86.7, 83.8, 91.4 and 87.3%, respectively, much better than that of the positive control chlorothalonil. Also, compound 5a (R= Ph) had inhibition rate of 87.9% against Rhizoeotnia solani, and compound 5b (R= o-CH3 Ph) had inhibition rates of 87.6 and 89% against Bipolaris maydis and Colleterichum orbicala, respectively. In order to develop novel and promising antifungal compounds against P. piricola, the analysis of three-dimensional quantitative structure-activity relationship (3D-QSAR) was carried out using the CoMFA method on the basis of their antifungal activity data, and a reasonable and effective 3D-QSAR model (r2 = 0.944, q2 = 0.685) has been established. In addition, the theoretical study of molecular docking revealed that the target compounds could bind to and interact with the site of cytochrome bc1 complex.

Although nanomaterials are widely studied in biomedical applications, the major concern of nanotoxicity still exists. Therefore, numerous works have been conducted on the interactions of various biomolecules with various types of nanomaterials, including carbon nanotube, graphene, fullerene and etc. However, the size effect of nanomaterials is poorly documented, especially the ultra-small particles. Here, the interactions of the smallest carbon nanoparticle (NP), C28, with cell membrane were studied using molecular dynamics (MD) simulations. The results show that similar to fullerene C60, the C28 NPs can self-assemble into stable clusters in water. Inside membrane, the C28 NPs are more prone to aggregate to form clusters than C60 NPs. The reason of the C28 aggregation is characterized by potential of mean force (PMF) and can be explained by the polarized nature of C28 NPs while the acyl chains of lipids are nonpolar. At the C28 cluster regions, the thickness of the membrane is significantly reduced by the C28 aggregation. Accordingly, the membrane losses its structural integrity and translocation of water molecules through it were observed. Thus, these results predict a stronger cytotoxicity to cells than C60 NPs. The present findings might shed light on the understanding of the cytotoxicity of NPs with different size and would be helpful for the potential biomedical applications of carbon NPs, especially as antibacterial agents.

Nanomaterial defects occur widely due to various situations such as synthesis imperfections, exposure to harsh environment, or even intentional designs. However, the consequence of nanomaterial defects on their interfacing biological systems remains largely unknown. Here, we study the interaction of a defective graphene nanosheet with a widely used model protein, YAP65WW-domain, using molecular dynamics simulations. We find that local defects on graphene consistently act to unfold the YAP65WW-domain. Protein residues bound to the graphene defect are tightly anchored due to favorable electrostatic interactions. While the residues at the interface are highly restrained, thermal movements of other parts of the protein act to denature and unfold the entire protein. In contrast, control simulations of protein binding on ideal graphene reveal a well preserved native structure with no unfolding events detected. Our present findings elucidate the role of graphene defects on protein adsorption and emphasize the need for improved understanding of nanomaterial defects in potential biomedical applications.

Palladium isotopes as fission products in used nuclear fuel (UNF) represent precious alternative resources of this noble metal besides its natural reserves and therefore has a high extraction value. However, although solvent extraction of Pd from UNF has been considered for several decades, its practical use is still challenging mostly originating from the harsh fuel reprocessing conditions that lead to the extractant decomposition and the vast co-existing metal ions that depress the extraction efficiency. Herein, we present an interlayer synergistic binding strategy, a metal-recognition manner markedly deviating from chelation within a single ligand molecule in solvent extraction, for selective palladium chelation by a radiation-resistant and acid-stable salicylaldimine-based covalent organic framework (COF-TzDa), where the binding sites are pre-organized and spatially separated for the preference of Pd coordination between adjacent COF layers. COF-TzDa, as expected, shows ultrahigh extraction selectivity towards Pd ions both in static and dynamic conditions, primarily due to that the preorganized Pd-specific binding sites are less prone to match other undesired metal ions. Fast adsorption kinetics, high adsorption capacity (265.4 mg g-1), and more importantly one-round enrichment and purification of Pd from the simulated high level nuclear waste solution are unprecedentedly achieved. The powder X-ray diffraction analysis, X-ray photoelectron spectroscopy results, and in-depth density functional theory corroborate the interlayer synergistic binding to be the result of enol-to-keto tautomerization where oxygen donors from two adjacent layers work together in a cooperative fashion. This work demonstrates the feasibility of structure-engineering of framework materials in designing upgraded adsorbent for targeted guests.

Using molecular dynamics simulations, we investigate the performance of molybdenum disulfide nanotubes (MoS2 NTs) as a medium for energy gas storage (hydrogen and methane). Two representative MoS2 NTs, (12, 12) and (6, 6), are considered in our present study. MoS2 NTs are found to effectively attract hydrogen and methane molecules through their surface and interior. Under storage conditions (175 K and 10 MPa), the storage capacity of methane in MoS2 NTs can reach 7–8 wt%, depending on the diameter of MoS2 NTs. For hydrogen, the storage capacity is around 0.7–0.9 wt%. The gas weight percentage is linearly dependent on the environmental pressure from 10 MPa to 1 MPa at constant temperature. Meanwhile, adsorption demonstrates an exponential relationship with the system temperature from 175 K to 425 K when pressure is maintained constant. Dynamic pressure simulations reveal that up to 80–90% of the stored gases can be spontaneously released as the pressure decreases from 10 MPa to 1 MPa, with methane slightly more efficient than hydrogen, indicating high cyclic storage performance. Our present theoretical findings shed new light on the utilization of MoS2 nanomaterials as a novel gas storage platform and we hope our results will promote future experimental efforts.

The adsorption of amyloid-β peptide (Aβ) onto graphene nanosheets with curvature at a neutral pH has been studied by using molecular dynamics simulations in combination with umbrella sampling. We found that Aβ adsorbed onto graphene with distinct characteristics, causing the breakage of hydrogen bonds which leads to its conformational change. Interestingly, the adsorption capacity of graphene's surface varies significantly depending on its curvature, namely, the surface with negative curvature has a higher probability to adsorb the Aβ than the one with positive curvature. This phenomenon is further evidenced by the binding energy between the complex of graphene and Aβ derived from the potential of mean force (PMF). The hydrophobic interactions and the direct dispersion interactions between the graphene nanosheet and the Aβ play a dominant role in the adsorption process. These findings indicate that not only is the chemical composition an important factor but also the shape of the nanoparticle is important in determining its interaction with proteins: the contacting surface curvature can lead to different adsorption capability.

The development of biocompatible nanomaterials for smart drug delivery and bioimaging has attracted great interest in recent years in biomedical fields. Here, the interaction between the recently reported nitrogenated graphene (C2N) and a prototypical protein (villin headpiece HP35) utilizing atomistic molecular dynamics simulations is studied. The simulations reveal that HP35 can form a stable binding with the C2N monolayer. Although the C2N–HP35 attractive interactions are constantly preserved, the binding strength between C2N and the protein is mild and does not cause significant distortion in the protein's structural integrity. This intrinsic biofriendly property of native C2N is distinct from several widely studied nanomaterials, such as graphene, carbon nanotubes, and MoS2, which can induce severe protein denaturation. Interestingly, once the protein is adsorbed onto C2N surface, its transverse migration is highly restricted at the binding sites. This restriction is orchestrated by C2N's periodic porous structure with negatively charged “holes,” where the basic residues—such as lysine—can form stable interactions, thus functioning as “anchor points” in confining the protein displacement. It is suggested that the mild, immobilized protein attraction and biofriendly aspects of C2N would make it a prospective candidate in bio- and medical-related applications.