The surface charge of the plasma membrane (PM) and the large salt content of the extracellular space ensure a significant role of the electrostatic effect dictating the interaction between the PM and an approaching nanoparticle (NP). In this article, we theoretically study the case of an ionizable silica NP approaching the PM. We witness that the surface charge of the silica NP, dictated by the surface ionization of the silica in the electrostatic environment created by the PM surface charge and the extracellular ion concentration, decreases as it approaches the PM. In other words, a silica NP is more negative away from the PM than in close proximity to the PM. Accordingly, we witness a significantly lower repulsion between the PM and NP favoring the approach and the interactions of the silica NP with the PM. Additionally, the presence of the silica NP in the vicinity of the PM induces a large nonisopotentiality, even across a fully permeable PM. We anticipate that these findings will be critically important in the better design of the widely used silica NPs for targeted drug and gene deliveries.
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http://dx.doi.org/10.1021/acs.langmuir.9b00036 | DOI Listing |
J Phys Chem B
January 2025
Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.
Introduction of non-DLVO forces by nonionic surfactants brings about fascinating changes in the phase behavior of silica nanosuspensions. We show here that alterations in the interaction and wetting properties of negatively charged silica nanoparticles (Ludox® LS) in the presence of polyethylene oxide-polypropylene oxide-polyethylene oxide-based triblock copolymers called Pluronics lead to the formation of stable o/w Pickering emulsions and interparticle attraction-induced thermoresponsive liquid-liquid phase separations. The results make interesting comparisons with those reported for Ludox® TM nanosuspensions comprising larger silica nanoparticles.
View Article and Find Full Text PDFAnal Chim Acta
January 2025
State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, 130000, PR China. Electronic address:
Nitrite is widely used as a food additive, and it is of great significance to realize accurate detection of nitrite for food safety. Electrochemical technique is characterized by simple operation and portability, which enables rapid and accurate detection. The key factors affecting the nitrite detection performance are the electrocatalytic activity and interfacial electron transfer efficiency of the electrode.
View Article and Find Full Text PDFBiochim Biophys Acta Biomembr
January 2025
Land and Food Systems, University of British Columbia, Vancouver, Canada; Faculty of Agricultural, Life and Environmental Sciences, University of Alberta, Edmonton, Canada. Electronic address:
The Solanum tuberosum (common potato) plant specific insert (StPSI) is an antimicrobial protein domain that exhibits membrane-disrupting and membrane-fusing activity upon dimerization at acidic pH, activity proposed to involve electrostatic attraction and membrane anchoring mediated by specific positively-charged and conserved tryptophan residues, respectively. This study is the first to employ an in silico mutagenesis approach to clarify the structure-function relationship of a plant specific insert (PSI), where ten rationally-mutated StPSI variants were investigated using all-atom and coarse-grained molecular dynamics. The tryptophan (W) residue at position 18 (W18) of wild-type StPSI was predicted to confer structural flexibility to the dimer and mediate a partial separation of the assembled monomers upon bilayer contact, while residues including W77 and the lysine (K) residue at position 83 (K83) were predicted to stabilize secondary structure and influence association with the model membrane.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Longpan Road 159, Nanjing 210037, China. Electronic address:
The weak cohesive strength of tissue adhesives hinders their practical applications. To overcome this challenge, we develop a green bio-adhesive that balances both cohesion and adhesion, drawing inspiration from the natural adhesion mechanisms of mussels. This bio-adhesive, referred to as OTS, was ingeniously crafted through the co-assembly of multi-surface-charged chitin nanofibers (OAChN) and tannic acid (TA), integrated with silk fibroin (SF), resulting in a material with enhanced cohesive strength and robust adhesive properties.
View Article and Find Full Text PDFACS Nano
January 2025
Biosensor National Special Laboratory, Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, PR China.
Single cell adhesion plays a significant role in numerous physiological and pathological processes. Real-time imaging and quantification of single cell adhesion kinetics and corresponding cell-substrate mechanical interaction forces are crucial for elucidating the cellular mechanisms involved in tissue formation, immune responses, and cancer metastasis. Here, we present the development of a plasmonic-based nanomechanical sensing and imaging system (PNMSi) for the real-time measurement of single cell adhesion kinetics and associated nanomechanical forces with plasmonic tracking and monitoring of cell-substrate interactions and the accompanying nanoscale fluctuations.
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