Boron nanosheets as a phosphatase mimicking nanozyme with ultrahigh catalytic activity for prodrug-based cancer therapy.

Boron nanosheets (BNSs) are reported as a new phosphatase mimicking nanozyme. Surprisingly, the catalytic rate of BNSs is up to 17 times those of known phosphatase mimicking nanozymes. By adding polyols and Lewis bases, the catalytic activity of BNSs was attributed to the Lewis acidity of the B centers of the BNSs. Theoretical investigation shows that the B centers are responsible for the catalytic hydrolysis of phosphoesters. Moreover, the biomimetic activity of the BNSs was further explored for enhancing anticancer therapy through nanozyme-catalyzed prodrug conversion.

Improved selectivity of molecularly imprinted polymers based on the synergistic action of hydrogen bond and electrostatic interaction.

Based on the synergistic action of hydrogen bond and electrostatic interaction, provided by methacrylic acid and 2-aminoethyl ester hydrochloride (FM2), respectively, novel molecularly imprinted polymers (SA-MIPs) were designed to improve its selective recognition ability. Diclofenac sodium (DFC) was chosen as the template molecule of this study. The interaction and their recognition sites between two functional monomers and templates were confirmed by nuclear magnetic resonance hydrogen spectroscopy. Because of the synergistic action of hydrogen bond and electrostatic interaction, the imprinting factor (IF) of SA-MIPs (IF = 2.26) is superior to the corresponding monofunctional monomer imprinting materials (IF = 1.52, 1.20) and the materials using two functional monomers with an only single type of interaction (IF = 1.54, 1.75). The results of selective adsorption experiments indicate that the selective recognition ability of SA-MIPs is significantly better than that of the other four MIPs, and the difference in selectivity coefficient for methyl orange is the largest between SA-MIPs and the MIPs only using FM2, which is about 70 times. In addition, x-ray photoelectron spectroscopy was used to verify the interaction between SA-MIPs and the template. This work and its explanation of the interaction mechanism at the molecular level will be helpful for the rational design of novel MIPs with higher selectivity. Besides, SA-MIPs have good adsorption performance (37.75 mg/g) for DFC in aqueous solutions, which could be used as potential adsorption materials for the effective removal of DFC in the aquatic environment.

Pickering emulsion-enhanced Vibrio fischeri assay for ecotoxicity assessment of highly hydrophobic polycyclic aromatic hydrocarbons.

Accurate ecotoxicity assessment of contaminated soil is critical to public health, and the luminescent bacteria (Vibrio fischeri) method is the most commonly used. Hydrophobic compounds such as polycyclic aromatic hydrocarbons (PAHs) in soil cannot be in contact with luminescent bacteria due to their low water solubility so that the luminescence inhibitory effect cannot be observed. The underestimated biological toxicity makes the test unreliable and en-dangers public health and safety. The commonly adopted improved method of adding cosolvents has limited effect, it was only effective for low-hydrophobicity chemicals and could not be used for ecotoxicity evaluation of high-hydrophobicity chemicals. Therefore, we constructed Pickering emulsions using luminescent bacteria modified with n-dodecanol in which PAHs were dissolved in the oil phase, n-tetradecane. Then the luminescent bacteria could tightly adhere to the oil-water interface and contact PAHs. As a result, their bioluminescence was suppressed to varying degrees depending on the chemical species and concentrations. With no solubility limitation, highly hydrophobic PAHs could even completely inhibit bacterial bioluminescence, hence the toxicity information was accurately displayed and the median effect concentration (EC50) values could be calculated. This Pickering emulsion-based method was successfully applied for the accurate ecotoxicity evaluation of highly hydrophobic PAHs and soil samples contaminated with them, which all previous methods could not achieve. This method overcomes the problem of ecotoxicity evaluation of hydrophobic compounds, and has great potential for practical application, whether it is pure chemicals or various real samples from the ecological environment.