Fuyi Wang

Water clusters with distinct structures in confined nanochannels exhibit unusual transport phenomena such as fast permeation, yet how to functionalize nanochannels to regulate this process and enhance water transport remains elusive. Herein, we report a water transmembrane transport mechanism based on the dissociation of water clusters and, accordingly, develop a highly permeable nanofiltration membrane with polyhydroxy quaternized interface. The results, observed by in situ liquid time-of-flight secondary ion mass spectrometry in combination with molecular dynamics simulation, reveal that the functional groups (-OH and quaternary-N⁺) of membrane pore entrances can enthalpically/entropically favorably dissociate water clusters, i.e., (H ₂ O) ₅ H ⁺ , into smaller species, i.e., (H ₂ O) ₃ H ⁺ with higher transport mobility through hydrogen bond interactions based hydration competition, which reduces water transmembrane transport energy barriers and broadens the cross-sectional area available to water molecules, thus improving the water permeance. The polyhydroxy quaternized membrane exhibits high permeability with a membrane flux of 43.01 L m ⁻² h ⁻¹ bar ⁻¹ , while maintaining favorable divalent salt retention performance and mechanical properties, which effectively improves the selectivity-permeability upper bound of the nanofiltration membrane. Our findings demonstrate an interface-functionalized strategy for regulating the water cluster structure, showing implications for various applications including nanofluidics, desalination, bio-medicine, and energy technology, etc.

Although conducting polymers (CPs) have catalyzed the development of advanced optoelectronic devices, their performance in aqueous environments remains largely underexplored due to the quenching of electron/hole by water molecules. In this study, we present an unconventional electrochemical strategy to achieve unexpected hydroxyl radical (•OH) generation at a remarkably low voltage of 0.4 V (vs. Ag/AgCl). This is realized through an integrated system comprising CPs of poly(fluorene‐alt‐thienopyrazine) (PFTP) adsorbed onto the partially oxidized copper sheet. Microscopy and surface analysis techniques demonstrated that the Cu ₂ O layer on the copper sheet surface could enhance the interaction between PFTP and copper sheet, thereby tuning the oxidation potential of PFTP from 1.27 to 1.70 V (vs. Ag/AgCl). It was the specific shift that makes thermodynamically capable of oxidizing water into •OH upon electrical stimulation. Theoretical calculations and mass spectrometry imaging results indicated that the PFTP/Copper interaction is mainly attributed to the interaction between the S atoms on the PFTP backbone and Cu ₂ O sites, and the weak interfacial interaction effectively tuned the HOMO energy level of PFTP. Finally, the PFTP/Copper system demonstrates a superior sterilization rate of 99% against bacterial biofilms at low operating voltages, offering a sustainable and energy‐efficient solution for anti‐biofouling applications.

Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) has emerged as a pivotal analytical technique for characterizing the complex surface and interfacial chemistry of battery materials. This review article comprehensively discusses the fundamental principles and unique attributes of ToF‐SIMS, highlighting its advantages such as ultrahigh surface sensitivity (ppm‐ppb), high spatial resolution (< 50 nm laterally, and < 1 nm in depth), and high mass resolution for hydrogen and isotope study. In the field of battery study, these attributes enable precise, multi‐dimensional characterization of electrode‐electrolyte interphases (EEIs). In the previous works, ToF‐SIMS has been employed to resolve the composition and structures at the nanoscale of EEIs, track the dynamic evolution and degradation of electrode surface, differentiate artificial coating interphases from the bulk materials, and detect isotopes for mechanistic studies. The burgeoning field of in situ liquid ToF‐SIMS for probing the authentic solvation structures and aging mechanism of electrolytes is also highlighted. Challenges of using ToF‐SIMS for battery study, such as the matrix effects, beam‐induced damage, and need for higher sensitivity and depth resolution, are also discussed. In summary, ToF‐SIMS provides multi‐dimensional insights into battery interfaces, which help to establish structure‐property correlations and will continuously guide the rational design of the next‐generation high‐performance energy storage systems.

Single-cell mass spectrometry enables label-free and high-throughput molecular analysis of individual cells. However, conventional vacuum-based secondary ion mass spectrometry (SIMS) faces challenges in probing metabolism of single living cells under native physiological conditions. Here, we introduce a liquid SIMS platform coupled with a vacuum-compatible cell-culture device, which allows in-situ metabolomic profiling of single living cells in their native culture environment without any pretreatment. This platform uniquely enables direct nanoscale interfacial characterization, and we report for the first time the determination, via MS depth profiling, of a lipid bilayer with a SiN-equivalent thickness of ∼8.6 nm in a single living human nonsmall cell lung cancer (A549) cell. As a proof of concept, we applied this method to investigate metabolomic changes linked to cisplatin resistance in A549 cells. Our findings indicate upregulation of cholesterol, phosphatidylcholine, and low-unsaturation fatty acids in resistant cells, and we demonstrate that inhibiting cholesterol synthesis effectively reduces drug resistance. This work underscores the potential of liquid SIMS for in-situ metabolic profiling during complex biological processes.

Solid-state electrolytes have been identified as promising candidates to overcome limitations of lithium-sulfur batteries in polysulfide shuttle and lithium dendrite growth. However, an essential mechanistic understanding of composite sulfur (S) cathodes is still lacking in all-solid-state lithium-sulfur (ASSLS) batteries. Herein, in situ atomic force microscopy and Raman spectroscopy were conducted to unravel S cathode processes during cycling. The S particles gradually expand and fuse upon discharge, which is ascribed to the electrochemical conversion to lithium sulfide. The volume variation exhibits poor reversibility upon charge, which is the origin of the capacity fading of the S cathode. Moreover, side reactions occur at the interface of S/Li₁₀GeP₂S₁₂ (LGPS) in the cathode, manifested as simultaneous S dissolution and LGPS decomposition, which aggravate consumption of active materials and increase ion transport resistance. These straightforward evidence and in-depth studies uncover the S cathode process and enrich fundamental comprehensions of reaction mechanisms in ASSLS batteries.

We previously discovered that human nuclear cofactor PC4 selectively binds to a double-stranded oligodeoxynucleotide (dsODN) crosslinked by a trans -platinum anticancer complex, trans -[PtCl ₂ (NH ₃ )(thiazole)] ( trans- PtTz), which was further demonstrated to reduce its cytotoxicity by mediating DNA repair, though the molecular mechanism was unclear. In this work, we developed an amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) coupled to online peptic digestion to dissect interaction interface and binding sites between PC4 and a trans -PtTz crosslinked 15-mer dsODN ( trans -PtTz- III ). Using online HDX-MS, we identified a 1:1 binding stoichiometry and key involvement of the β3–β5 sheets (K80–Q109) in recognition. Molecular dynamic simulations suggest a 2:2 binding mode and the C-terminal helices slightly loosen, with Arg86 being critical for the recognition and interaction between PC4 and trans -PtTz- III . More importantly, site-directed mutation of Arg86 weakened the binding of PC4 to trans -PtTz- III in vitro and promoted the cytotoxicity of trans -PtTz against A549 cells. This work profiles the detailed interaction mechanism of PC4 with trans -PtTz damaged dsODN, and provides a new paradigm for the further research of the cellular response to platinum induced DNA damage.

Background: To battle the side effects of anticancer Pt(II) drug cisplatin, the development of photoactivatable and/or intracellular reduction-activatable Pt(IV) prodrugs has become a promising strategy. Methods: Herein, two novel Pt(IV) prodrugs, namely, cis,cis,trans-[Pt^IV(NH₃)₂(Cl)₂(OH)(probenecid)]) (SPP) and cis,cis,trans-[Pt^IV(NH₃)₂(Cl)₂(probenecid)₂] (DPP) bearing mono- and di-probenecid at the axial positions of oxoplatin have been synthesized via covalently linking of carboxylate group in probenecid, which is a well-established clinic drug by inhibiting organic anion transporter 1 (OAT1) to reduce cisplatin-induced nephrotoxicity, with the axial hydroxyl group(s) in oxoplatin. The promising cytotoxicity of SPP and DPP against MCF-7, T47D breast cancer cells and the MDA-MB-231 triple-negative breast cancer cells was evaluated, and the mechanism of action of the two Pt(IV) prodrugs was investigated by apoptosis assay and Western blot assay. Results: SPP exhibits a comparable cytotoxicity to cisplatin against MCF-7 and T47D breast cancer cells, while it shows 2.1-fold higher cytotoxicity than cisplatin against MDA-MB-231 cells. DPP was shown to be more cytotoxic than SPP, and exhibits 8.7-, 7.5-, and 2.3-fold higher cytotoxicity than cisplatin against MCF-7, T47D, and MDA-MB-231 cells, respectively. Apoptosis assays revealed a similar early-apoptotic cell death mechanism to cisplatin for both SPP and DPP. The enhanced cellular and nuclear uptake of DPP compared to cisplatin contributes to its promising anticancer efficacy. DPP can bind to OAT1 in cancer cells, which may synergistically enhance the cytotoxicity of the Pt(IV) anticancer prodrugs. Conclusions: The direct conjugation of probenecid to the axial positions of oxoplatin confers the resulting Pt(IV) prodrugs a multitargeting property, significantly promoting the cytotoxicity of the resulting Pt(IV) complexes. This finding provides a practical strategy for drug design and cancer treatment based on platinum complexes.