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Sum-frequency generation (SFG) spectroscopy provides a unique optical probe for interfacial molecules with interface-specificity and molecular specificity. SFG measurements can be further carried out at different polarization combinations, but the target of the polarization-dependent SFG is conventionally limited to investigating the molecular orientation. Here, we explore the possibility of polarization-dependent SFG (PD-SFG) measurements with heterodyne detection (HD-PD-SFG). We stress that HD-PD-SFG enables accurate determination of the peak amplitude, a key factor of the PD-SFG data. Subsequently, we outline that HD-PD-SFG can be used not only for estimating the molecular orientation but also for investigating the interfacial dielectric profile and studying the depth profile of molecules. We further illustrate the variety of combined simulation and PD-SFG studies.
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http://dx.doi.org/10.1021/acs.jpcb.2c02178 | DOI Listing |
Anal Chem
September 2025
Jiaxing Key Laboratory of Molecular Recognition and Sensing, College of Biological and Chemical Engineering, Jiaxing University, Jiaxing 314001, China.
Despite the promise of electrochemical biosensors in amplified nucleic acid diagnostics, existing high-sensitivity platforms often rely on a multilayer surface assembly and cascade amplification confined to the electrode interface. These stepwise strategies suffer from inefficient enzyme activity, poor mass transport, and inconsistent probe orientation, which compromise the amplification efficiency, reproducibility, and practical applicability. To address these limitations, we report a programmable dual-phase electrochemical biosensing system that decouples amplification from signal transduction.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.
Among the different types of HIV-1 maturation inhibitors, those that stabilize the junction between the capsid protein C-terminal domain (CA) and the spacer peptide 1 (SP1) within the immature Gag lattice are promising candidates for antiretroviral therapies. Here, we report the atomic-resolution structure of CA-SP1 assemblies with the small-molecule maturation inhibitor PF-46396 and the assembly cofactor inositol hexakisphosphate (IP6), determined by magic angle spinning (MAS) NMR spectroscopy. Our results reveal that although the two PF-46396 enantiomers exhibit distinct binding modes, they both possess similar anti-HIV potency.
View Article and Find Full Text PDFBiol Cybern
September 2025
Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, 61801, IL, USA.
In this article, a biophysically realistic model of a soft octopus arm with internal musculature is presented. The modeling is motivated by experimental observations of sensorimotor control where an arm localizes and reaches a target. Major contributions of this article are: (i) development of models to capture the mechanical properties of arm musculature, the electrical properties of the arm peripheral nervous system (PNS), and the coupling of PNS with muscular contractions; (ii) modeling the arm sensory system, including chemosensing and proprioception; and (iii) algorithms for sensorimotor control, which include a novel feedback neural motor control law for mimicking target-oriented arm reaching motions, and a novel consensus algorithm for solving sensing problems such as locating a food source from local chemical sensory information (exogenous) and arm deformation information (endogenous).
View Article and Find Full Text PDFSmall Methods
September 2025
Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China.
Natural polyreactive antibodies achieve enhanced avidity through heterogeneous ligand binding. However, engineering synthetic heteroligation systems with precise control over recognition motif orientation and distance remains challenging. Here, a DNA framework-based strategy is presented to program heterotypic binding by spatially organizing bivalent aptamers targeting platelet-derived growth factor-BB (PDGF-BB).
View Article and Find Full Text PDFAdv Mater
September 2025
State Key Laboratory of Fabrication Technologies for Integrated Circuits, Chinese Academy of Sciences, Beijing, 100029, China.
The monolayer transistor, where the semiconductor layer is a single molecular layer, offers an ideal platform for exploring transport mechanisms both theoretically and experimentally by eliminating the influence of spatially correlated microstructure. However, the structure-property relations in polymer monolayers remain poorly understood, leading to low transistor performance to date. Herein, a self-confinement effect is demonstrated in the polymer monolayer with nanofibrillar microstructures and edge-on orientation, as characterized by the 4D scanning confocal electron diffraction method.
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