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The presence of large hydrophobic aromatic residues in cell-penetrating peptides or proteins has been demonstrated to be advantageous for their cell penetration. This phenomenon has also been observed when AuNPs were modified with peptides containing aromatic amino acids. However, it is still not clear how the presence of hydrophobic and aromatic groups on the surface of anionic AuNPs affects their interaction with lipid bilayers. Here, we studied the interaction of a range of anionic amphiphilic AuNPs coated by different combinations of hydrophobic and anionic ligands with four different types of synthetic lipid vesicles. Our results demonstrated the important role of the surface aromatic or bulky groups, relative to the hydrocarbon chains, in the interaction of anionic AuNPs with lipid bilayers. Hydrophobic interaction itself arising from the insertion of aromatic/bulky ligands on the surface of AuNPs into lipid bilayers is sufficiently strong to cause overt disruption of lipid vesicles and cell membranes. Moreover, by comparing the results obtained from AuNPs coated with aromatic ligands and cyclohexyl ligands lacking aromaticity respectively, we demonstrated that the bulkiness of the terminal groups in hydrophobic ligands instead of the aromatic character might be more important to the interaction of AuNPs with lipid bilayers. Finally, we further correlated the observation on model liposomes with that on cell membranes, demonstrating that AuNPs that are more disruptive to the more negatively charged liposomes are also substantially more disruptive to cell membranes. In addition, our results revealed that certain cellular membrane domains that are more susceptible to disruption caused by hydrophobic interactions with nanoparticle surfaces might determine the threshold of AuNP-mediated cytotoxicity. [ABSTRACT FROM AUTHOR]

Creating nanoparticle dimers has attracted extensive interest. However, it still remains a great challenge to synthesize heterodimers with asymmetric compositions and synergistically enhanced functions. In this work, we report the synthesis of high quality heterodimers composed of porphyrinic nanoscale metal-organic frameworks (nMOF) and lanthanide-doped upconversion nanoparticles (UCNPs). Due to the dual optical properties inherited from individual nanoparticles and their interactions, absorption of low energy photons by the UCNPs is followed by energy transfer to the nMOFs, which then undergo activation of porphyrins to generate singlet oxygen. Furthermore, the strategy enables the synthesis of heterodimers with tunable UCNP size and dual NIR light harvesting functionality. We demonstrated that the hybrid architectures represent a promising platform to combine NIR-induced photodynamic therapy and chemotherapy for efficient cancer treatment. We believe that such heterodimers are capable of expanding their potential for applications in solar cells, photocatalysis, and nanomedicine. [ABSTRACT FROM AUTHOR]

To prepare and identify ACE-inhibitory peptides originated from sesame seed protein, peptides with strong ACE-inhibitory activities were obtained via the optimization of protease and hydrolysis conditions, and these peptides were purified and identified by membrane separation, gel filtration, and liquid chromatography-mass spectrometry. Results showed that the dual-enzyme comprised alcalase and trypsin with the enzyme activity ratio of 3:7 was suitable to produce ACE-inhibitory peptides. The highest ACE-inhibitory activity of 98.10 ± 0.26% was obtained at the following parameters, pH 8.35, E/S ratio of 6,145 U/g, and hydrolysis time of 4.4 hr. ISGAQPSLR and VVISAPSK ranked the first and second ACE-inhibitory activity among 15 identified ACE-inhibitory peptides. Both peptides influenced ACE via binding with the S1 pocket, S2 pocket, and Zn2+ ion. ISGAQPSLR even impacted the S1' pocket. ISGAQPSLR and VVISAPSK acted as a competitive and noncompetitive inhibitor, respectively. ACE-inhibitory peptides derivated from sesame seed protein have potential applications in functional food. Practical applications: Although sesame seed protein is proven as the precursor of ACE-inhibitory peptide, preparing ACE-inhibitory peptide from sesame seed protein is still suffering from insufficient information on hydrolysis condition and the peptide sequence. Therefore, the performance of the typical protease on preparing ACE-inhibitory peptide from sesame seed protein has been evaluated, the effect of the amino acid composition of sesame seed protein and cleavage specificity of protease on the generation of ACE-inhibitory peptide has been investigated, hydrolysis conditions have been optimized, the peptide sequence has been identified to illuminate the effect of sesame seed protein fraction on the formation of ACE-inhibitory peptide and discuss the structural characteristics. ACE-inhibitory peptides originating from sesame seed protein could apply in functional food. It is promising for dual-enzyme hydrolysis to utilize in preparation of high-value bioactive peptides. [ABSTRACT FROM AUTHOR]