Significance: Development of precise protocols for accurate site-specific conjugation of monodisperse inorganic nanoparticles to large biomolecules and bionanoparticles is one of the challenges in contemporary bionanoscience and nanomedicine, providing new tools for bioimaging and tracking in biological systems. Here we report a success in labeling enteroviruses by atomically precise thiol-stabilized gold clusters with 1.5-nm metal cores that bind, via a covalent link, to cysteines that are close to the viral surface. It is shown that the infectivity of the viruses is not compromised by this labeling procedure. These advances allow for future investigations of the structure−function relations of enteroviruses and enterovirus-related virus-like particles, including their entry mechanisms into cells and uncoating in cellular endosomes.

Ultrafast laser processing has emerged as a versatile technique for modifying materials and introducing novel functionalities. Over the past decade, this method has demonstrated remarkable advantages in the manipulation of 2D layered materials, including synthesis, structuring, functionalization, and local patterning. Unlike continuous‐wave and long‐pulsed optical methods, ultrafast lasers offer a solution for thermal heating issues. Nonlinear interactions between ultrafast laser pulses and the atomic lattice of 2D materials substantially influence their chemical and physical properties. This paper highlights the transformative role of ultrafast laser pulses in maskless green technology, enabling subtractive, and additive processes that unveil ways for advanced devices. Utilizing the synergetic effect between the energy states within the atomic layers and ultrafast laser irradiation, it is feasible to achieve unprecedented resolutions down to several nanometers. Recent advancements are discussed in functionalization, doping, atomic reconstruction, phase transformation, and 2D and 3D micro‐ and nanopatterning. A forward‐looking perspective on a wide array of applications of 2D materials, along with device fabrication featuring novel physical and chemical properties through direct ultrafast laser writing, is also provided.

We present the synthesis, separation, and characterization of covalently-bound multimers of para-mercaptobenzoic acid (p-MBA) protected gold nanoclusters. The multimers were synthesized by performing a ligand-exchange reaction of a pre-characterized Au₁₀₂(p-MBA)₄₄ nanocluster with biphenyl-4,4′-dithiol (BPDT). The reaction products were separated using gel electrophoresis yielding several distinct bands. The bands were analyzed by transmission electron microscopy (TEM) revealing monomer, dimer, and trimer fractions of the nanocluster. TEM analysis of dimers in combination with molecular dynamics simulations suggest that the nanoclusters are covalently bound via a disulfide bridge between BPDT molecules. The linking chemistry is not specific to Au₁₀₂(p-MBA)₄₄. The same approach yields multimers also for a larger monodisperse p-MBA-protected cluster of approximately 250 gold atoms, Au_∼250(p-MBA)_n. While the Au₁₀₂(p-MBA)₄₄ is not plasmonic, the Au_∼250(p-MBA)_n nanocluster supports localized surface plasmon resonance (LSPR) at 530 nm. Multimers of the Au_∼250(p-MBA)_n exhibit additional transitions in their UV-vis spectrum at 630 nm and 810 nm, indicating the presence of hybridized LSPR modes. Well-defined structures and relatively small sizes make these systems excellent candidates for connecting ab initio theoretical studies and experimental quantum plasmonics. Moreover, our work opens new possibilities in the controlled synthesis of advanced monodisperse nanocluster superstructures.

Laser-induced two-photon oxidation modifies locally the electrical and optical properties of monolayer graphene allowing optical fabrication of all-graphene devices.

Understanding the dynamics of Förster resonance energy transfer (FRET) in fluorophore-functionalized nanomaterials is critical for developing and utilizing such materials in biomedical imaging and optical sensing applications. However, structural dynamics of noncovalently bound systems have a significant effect on the FRET properties affecting their applications in solutions. Here, we study the dynamics of the FRET in atomistic detail by disclosing the structural dynamics of the noncovalently bound azadioxotriangulenium dye (KU) and atomically precise gold nanocluster (Au₂₅(p-MBA)₁₈, p-MBA = para-mercaptobenzoic acid) with a combination of experimental and computational methods. Two distinct subpopulations involved in the energy transfer process between the KU dye and the Au₂₅(p-MBA)₁₈ nanoclusters were resolved by time-resolved fluorescence experiments. Molecular dynamics simulations revealed that KU is bound to the surface of Au₂₅(p-MBA)₁₈ by interacting with the p-MBA ligands as a monomer and as a π-π stacked dimer where the center-to-center distance of the monomers to Au₂₅(p-MBA)₁₈ is separated by ∼0.2 nm, thus explaining the experimental observations. The ratio of the observed energy transfer rates was in reasonably good agreement with the well-known 1/R⁶ distance dependence for FRET. This work discloses the structural dynamics of the noncovalently bound nanocluster-based system in water solution, providing new insight into the dynamics and energy transfer mechanism of the fluorophore-functionalized gold nanocluster at an atomistic level.