ACS Publications最新文献

{"title":"Assessing the Dynamics of Hemithioindigo-Based Photoswitches Using Multistate Molecular Mechanics.","authors":"Elias Harrer, Carolin Müller, Henry Dube, Dirk Zahn","doi":"10.1021/acs.jpca.5c04082","DOIUrl":"10.1021/acs.jpca.5c04082","url":null,"abstract":"<p><p>We outline a multistate molecular mechanics model for describing hemithioindigo-based photoswitches in the ground and excited (T₁) states, respectively. While retaining near quantum mechanical accuracy of the related Born-Oppenheimer potential energy profiles, the computational efficiency of our approach offers ns-scale molecular dynamics simulation runs featuring extended statistics of complex systems. Contrasting a series of different environments, we elucidate the explicit solvent effect on <i>Z</i>-<i>E</i> switching from the triplet-surface in terms of both energetics and kinetic aspects. Using thousands of trajectories, isomerization ratios and vibrational relaxation times are directly assessed from statistical sampling. On this basis, in-depth mechanistic understanding is achieved via trajectory committor analyses that unravel the key descriptors of the <i>Z-E</i> isomerization process.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"8312-8323"},"PeriodicalIF":2.8,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144715028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Spectroscopic and Computational Study of Dyes Based on Carbazole and TPA Donors, and Indane-Based Acceptors.","authors":"Amir Sohail, Pawel Wagner, Joseph I Mapley, Keith C Gordon","doi":"10.1021/acs.jpca.5c04213","DOIUrl":"10.1021/acs.jpca.5c04213","url":null,"abstract":"<p><p>Spectroscopic and computational analyses were employed to investigate a series of donor-acceptor dyes connected by a fused dithiophene (dctp) 4,4-dihexyl-4H-cyclopenta[2,1-b:3,4-b']. The donor units employed were triphenylamine (TPA) and carbazole (Cbz), while the acceptor units included Indane-based 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (InOCN) and 1H-indene-1,3(2H)-dione (IndO). A charge-transfer (CT) transition was evident in the electronic absorption spectra between 17,300 and 15,000 cm^-1. Each dye exhibited a singlet state of CT emission across all of the dyes. Emission spectra were observed from 14,700 to 13,100 cm^-1. Resonance Raman spectroscopy (RRS) was utilized to experimentally validate the time-dependent density functional (TD-DFT) findings. Furthermore, the results reveal that CT in 2-((6-(9-ethylcarbazol-3-yl)-4,4-dihexylcyclopenta[2,1-b:3,4-b']dithiophen-2-yl)methylene)indene-1,3-dione (PX134) and 2-(2-((6-(9-ethylcarbazol-3-yl)-4,4-dihexylcyclopenta[2,1-b:3,4-b']dithiophen-2-yl)methylene)-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (PX135) occurs from the donor-π system to the acceptor, whereas in ((6-(4-(diphenylamino)phenyl)-4,4-dihexylcyclopenta[2,1-b:3,4-b']dithiophen-2-yl)methylene)indene-1,3-dione (PX137) and 2-(2-((6-(4-(diphenylamino)phenyl)-4,4-dihexylcyclopenta[2,1-b:3,4-b']dithiophen-2-yl)methylene)-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (PX138), it proceeds from the donor to the π-acceptor units. These compounds exhibited distinct solvatochromic behavior in their absorption and emission spectra. These variations are analyzed using Lippert-Mataga (LM), McRae (MR), and Weller plots, which indicate changes in dipole moments between the ground and excited states. The linear slopes derived from the LM, MR, and Weller plots suggest a well-defined CT process with minimal specific solvent interactions. Density functional theory (DFT) modeling also suggests a significant level of planarity across all four dyes, and the experimental Raman spectra closely match the calculated Raman spectra. Compared to IndO groups, malononitrile units induce a greater CT character in the spectral emission behavior of each molecule. Variable temperature (VT) study reveals a blue shift with the increase in temperature across all of the dyes, indicating no evidence of aggregation.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"8346-8356"},"PeriodicalIF":2.8,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144936252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effective Ion Exclusion Requires Hydration Shell Stripping.","authors":"Ritwick Kali, Scott T Milner","doi":"10.1021/acs.jpcb.5c03471","DOIUrl":"10.1021/acs.jpcb.5c03471","url":null,"abstract":"<p><p>Sulfonated polystyrene membranes exhibit a nanostructure characterized by tortuous, interconnected hydrophilic pores enclosed by a hydrophobic polymer domain. The characteristic pore size plays a crucial role in determining the salt partition coefficients. To directly relate pore size to salt partitioning, we construct a simplified pore space confined between flat sulfonated polystyrene walls. By adjusting the separation between the polymer walls, we vary the pore size. Pores larger than subnanometer exclude ions because of the entropic barrier associated with the intrinsic counterion concentration. However, their concentration within the pore is far from uniform. The concentration at the pore center is low, resulting in a low entropy barrier and salt partition coefficients that are too large for practical ion exclusion applications like desalination and energy storage. Narrow pores, with dimensions smaller than hydrated ions, are required for effective ion exclusion. We find that ions begin to lose their hydration shell about half a nanometer away from the pore wall. Electrostatic interactions near the pore wall stabilize ions even as their hydration shells shrink, suggesting that neutral pores could be more effective for desalination.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"9268-9281"},"PeriodicalIF":2.9,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144936392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient Sampling of Free Energy Landscapes for the Calculation of Protein-Protein Binding Affinities in Membranes.","authors":"Ayan Majumder, John E Straub","doi":"10.1021/acs.jpcb.5c04286","DOIUrl":"10.1021/acs.jpcb.5c04286","url":null,"abstract":"<p><p>The accurate simulation of realistic biomembranes is a long-term goal in the field of membrane biophysics. Efforts to simulate increasingly complex lipid bilayers, consisting of multiple lipid types and proteins, have been hindered by the shortcomings of current force fields, both coarse-grained and all-atom, in the modeling of protein-protein and protein-lipid interactions. Due to the fundamental importance of protein dimerization to cellular signaling and protein trafficking, the study of protein-protein association and the related dimerization free energies has received significant attention in both simulations and experiments. Detailed comparisons of simulation results with NMR, crystallography, and FRET studies served as a test of the accuracy of the simulation methods and provided insights into the underlying structural distributions and thermodynamic driving forces defining the interactions. These comparisons have led to the conclusion that existing state-of-the-art simulation methods have failed to effectively sample the equilibrium between associated and dissociated states, leading to inaccurate estimates of binding constants and misrepresentation of the associated structural ensembles. Here, we discuss the drawbacks of previously used protocols and review our systematic development of effective computational methods for enhanced sampling simulations that exhaustively sample the native and non-native dimer conformations and provide precise estimates of the associated equilibrium binding constants. We conclude by identifying the most important current challenges to the field that must be met in closing the gap between simulation and experiment in the study of protein-protein association in the membrane.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"9031-9042"},"PeriodicalIF":2.9,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144936445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Direct Observation of Amyloid-β 42 Oligomer, Fibril, and Amorphous Aggregate Growth and Dissolution at Biomimetic Concentrations.","authors":"Radhika Sunil Menon, Peter G Wolynes, Peter G Vekilov","doi":"10.1021/acs.jpcb.5c03842","DOIUrl":"10.1021/acs.jpcb.5c03842","url":null,"abstract":"<p><p>The aggregation pathways of Aβ42 peptides are complex and can lead to both amyloids and nonamyloid aggregates. We use <i>in situ</i> atomic force microscopy imaging to monitor the assembly of aggregate structures and their dynamics. Two aggregation pathways emerge, one leading to amyloid fibrils and a second one that includes the formation of oligomers and apparently amorphous aggregates, which we identify as nonamyloid. Whereas the fibrils seem to require elevated peptide concentration to nucleate and grow, oligomers and amorphous aggregates form at near-physiological peptide concentrations. On the time scales of the experiments, the two aggregation pathways do not cross: the oligomers and aggregates do not participate in the fibrillization pathway and, analogously, secondary nucleation assisted by mature fibrils does not produce misfolded aggregates. We show that distinct Aβ42 fibril polymorphs form and coexist under identical conditions. Mature fibrils serve as substrates for secondary nucleation that leads to forked, branched, and thicker fibrils and, importantly, produces new fibril fragments. Aβ42 fibrils accumulate structural defects, with more defects generated at higher peptide concentrations. The defects lead to substantial variations of growth rate both over time and between different fibrils. The average growth rates of Aβ42 fibrils are about 50-fold faster than those of Aβ40 fibrils. Our findings are consistent with the basic premise of the polymorph selection hypothesis, according to which the late onset of Alzheimer's disease, its high clinical variability, and the presence of amyloid plaques in healthy individuals have their origins in differing toxicities and aggregation kinetics of distinct Aβ structural polymorphs.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"9083-9096"},"PeriodicalIF":2.9,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144936471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Orientation on the Dynamic Compression Properties of Poly(methyl methacrylate).","authors":"Hongyu Lu, Zitong Lu, Xueting Xu, Hanqin Rui, Mengyao Zheng, Zezong Yu, Mengyu Qi, Mao Wang, Xiaowen Zhang, Yue Yan","doi":"10.1021/acs.jpcb.5c02703","DOIUrl":"10.1021/acs.jpcb.5c02703","url":null,"abstract":"<p><p>Poly(methyl methacrylate) with biaxial stretching orientation (BO-PMMA) has superior mechanical properties compared to casting (unoriented, UO-PMMA), and is therefore widely used in the field of transparent structures. To investigate the effect of orientation on the dynamic compression properties of PMMA and establish a constitutive model applicable to BO-PMMA at different strain rates and service temperatures, this study conducted compression experiments on BO-PMMA at relatively low strain rates (1, 10, 100 s^-1) and high strain rates (2000, 3000, 4000 s^-1), as well as at room temperature (RT), 80 °C, and -40 °C. Through the quantitative comparison of the stress-strain curves of BO-PMMA and UO-PMMA, the influence mechanism of orientation on compressive mechanical behavior was elucidated. Based on the experimental results, the parameters of the DSGZ (Duan-Saigal-Greif-Zimmerman) phenomenological constitutive equation were fitted. Using this model, the PMMA with different orientations was numerically simulated and analyzed. The results indicated that increasing the strain rate or decreasing the temperature will increase the yield stress of PMMA. In particular, it was found that BO-PMMA performs more significant strain rate and low-temperature sensitivity than UO-PMMA. Meanwhile, the established constitutive model can effectively describe the dynamic compressive mechanical behavior of BO-PMMA and UO-PMMA at different strain rates and temperatures. Accordingly, it has a certain engineering application guidance value.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"9256-9267"},"PeriodicalIF":2.9,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144936387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic Reconfiguration of Pt(II) Supramolecular Assemblies via Ligand Exchange.","authors":"Elisa Pelorosso, Mirco Scaccaglia, Dario Alessi, Claudia Graiff, Alessandro Aliprandi","doi":"10.1021/acsami.5c10381","DOIUrl":"https://doi.org/10.1021/acsami.5c10381","url":null,"abstract":"<p><p>Supramolecular chemistry enables molecules to dynamically adapt and reorganize in response to their environment, providing a key route to achieving high levels of structural and functional complexity. This work explores a particular strategy for the dynamic and programmable self-assembly of luminescent platinum(II) complexes via sequential coordination-driven and hierarchical processes. The aggregation behavior and optical properties of square-planar Pt(II) complexes bearing a chromophoric terdentate N̂N̂N ligand and exchangeable monodentate ligands are highly dependent on the nature of the ancillary ligand, resulting in morphologically and photophysically distinct supramolecular structures. We demonstrate that these preassembled aggregates undergo dynamic ligand exchange reactions in solution, leading to metastable supramolecular states, including emissive gels, that are accessible exclusively through in situ exchange. Real-time fluorescence microscopy and NMR spectroscopy reveal both homogeneous and heterogeneous exchange pathways, governed by the identity of the initial complex and the incoming ligand. Remarkably, the system exhibits a degree of reversibility and structural memory. These findings establish a framework for stepwise self-assembly that bridges coordination chemistry with noncovalent interactions, offering a versatile platform for designing responsive nanostructures with tailored properties and a step toward adaptive, life-like materials with potential applications in sensing and optoelectronics.</p>","PeriodicalId":5,"journal":{"name":"ACS Applied Materials & Interfaces","volume":" ","pages":""},"PeriodicalIF":8.2,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145032385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Next-Generation Brain-Targeting Peptide: KS-487 Rivals Angiopep-2 in BBB Penetration with Enhanced Selectivity.","authors":"Kensuke Asukabe, Nagi Yamashita, Runa Fujimoto, Kotaro Sakamoto, Eijiro Miyako","doi":"10.1021/acs.bioconjchem.5c00352","DOIUrl":"https://doi.org/10.1021/acs.bioconjchem.5c00352","url":null,"abstract":"<p><p>KS-487 is a cyclic peptide previously reported to bind low-density lipoprotein receptor-related protein 1 (LRP1) and exhibit blood-brain barrier (BBB) permeability. In this study, we evaluated the in vivo BBB permeability and selectivity of KS-487 in comparison with those of Angiopep-2 (ANG2), a widely used linear LRP1-binding peptide. Indocyanine green (ICG)-labeled KS-487 and ANG2 were subcutaneously administered to mice, and their biodistribution was assessed at 24, 48, and 72 h by using in vivo imaging. ICG-KS-487 and ICG-ANG2 displayed comparable brain permeability and nearly identical time-course profiles. Notably, ICG-KS-487 demonstrated greater brain selectivity, defined as the ratio of brain to liver accumulation at 72 h. No adverse effects, including weight loss or histopathological abnormalities in major organs, were observed in mice treated with ICG-KS-487. These findings highlight the remarkable brain-targeting properties and safety profile of KS-487, supporting its potential utility as a targeting ligand for drug delivery to treat brain-related disorders.</p>","PeriodicalId":29,"journal":{"name":"Bioconjugate Chemistry","volume":" ","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145032433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative Approaches to Diabetic Wound Healing: Focusing on ROS and Redox Signals.","authors":"Akshita Jain, Tejaswini Kolipaka, Giriraj Pandey, Abhipsa Priyadarshinee, Niharika Puri, Swapnil Shinde, Saurabh Srivastava","doi":"10.1021/acs.molpharmaceut.5c00491","DOIUrl":"https://doi.org/10.1021/acs.molpharmaceut.5c00491","url":null,"abstract":"<p><p>Reactive oxygen species (ROS) play a critical role in the pathophysiology of diabetic wound healing. In the early stages, a moderate increase in ROS levels is beneficial, as it enhances phagocytic activity and provides defense against external damage. However, as healing progresses, excessive ROS production induces oxidative stress, reduces antioxidant enzyme activity, and leads to redox imbalance─ultimately contributing to the development of chronic diabetic wounds. This review comprehensively explores the role of ROS across various phases of the wound-healing process and elucidates the associated signaling pathways. It also examines the influence of ROS on key mediators of wound healing, including macrophages and matrix metalloproteinases. To modulate ROS levels and promote efficient wound healing, we discuss a range of antioxidant-based therapeutic strategies, such as the application of biopolymers and antioxidant enzymes. Among the diverse antioxidant strategies, nanozymes stand out for their inherent ability to mimic the catalytic functions of natural enzymes. Owing to their unique ROS scavenging capabilities, they hold great promise in addressing the key challenges associated with anti-ROS therapy. Nanozymes provide several distinct advantages, including enhanced stability, multifunctionality, and tunable catalytic activity. Moreover, they play a crucial role in modulating the inflammatory responses induced by the pathological microenvironment. The article further highlights the potential of phytoconstituents in mitigating oxidative stress and restoring redox balance. Additionally, it addresses current treatment strategies for diabetic wound management, while also evaluating the clinical progress and challenges associated with their development.</p>","PeriodicalId":52,"journal":{"name":"Molecular Pharmaceutics","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145032438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water-Activated Degradable Supramolecular Bioadhesive Powder for Underwater Tissue Adhesion and Wound Healing.","authors":"Hongjian Huang, Zongxuan Huang, Shuichang Chen, Xiaoyu Yang, Hu Zhao, Qinhui Chen, Haiqing Liu","doi":"10.1021/acs.biomac.5c01057","DOIUrl":"https://doi.org/10.1021/acs.biomac.5c01057","url":null,"abstract":"<p><p>Traditional suturing and stapling demand surgical skill and risk additional trauma, whereas conventional tissue adhesives falter on wet surfaces. Inspired by cement curing, a water-activated bioadhesive powder (WABP) was developed in this work. WABP was a mixture of tannic acid-terminated poly(lipoic acid) (TA-PLA) and arginine (Arg), in which the TA-PLA was synthesized through the Michael addition reaction of PLA containing disulfide radicals with TA possessing a radical quenching effect. Upon hydration, the powder swiftly formed a self-assembled coacervate adhesive, which exhibited antiswelling properties in underwater environments, a result of the combined effects of hydrogen bonding, electrostatic interactions, and hydrophobic associations. The WABP, harnessing the attributes of both powder and coacervate adhesives, was adept at conforming to an irregular wound shape and delivered stable bioadhesive performance. It demonstrated superior wound healing capabilities, antibacterial properties, favorable cytocompatibility, and histocompatibility. This supramolecular WABP offers a simple, multifunctional alternative to sutures for biomedical applications.</p>","PeriodicalId":30,"journal":{"name":"Biomacromolecules","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145032478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}