The origin of life is still one of humankind's great mysteries. At the transition between nonliving and living matter, protocells, initially featureless aggregates of abiotic matter, gain the ...structure and functions necessary to fulfill the criteria of life. Research addressing protocells as a central element in this transition is diverse and increasingly interdisciplinary. The authors review current protocell concepts and research directions, address milestones, challenges and existing hypotheses in the context of conditions on the early Earth, and provide a concise overview of current protocell research methods.
A review of the state of the art in protocell research is presented, following a concise overview of early Earth conditions relevant to protocell development. Compartment concepts, progress in experimental and theoretical research on protocell models, as well as fabrication technologies are summarized. The TOC image was inspired by a painting by W. Kandinsky.
Molecular polaritons are hybrid light-matter states that emerge when a molecular transition strongly interacts with photons in a resonator. At optical frequencies, this interaction unlocks a way to ...explore and control new chemical phenomena at the nanoscale. Achieving such control at ultrafast timescales, however, is an outstanding challenge, as it requires a deep understanding of the dynamics of the collectively coupled molecular excitation and the light modes. Here, we investigate the dynamics of collective polariton states, realized by coupling molecular photoswitches to optically anisotropic plasmonic nanoantennas. Pump-probe experiments reveal an ultrafast collapse of polaritons to pure molecular transition triggered by femtosecond-pulse excitation at room temperature. Through a synergistic combination of experiments and quantum mechanical modelling, we show that the response of the system is governed by intramolecular dynamics, occurring one order of magnitude faster with respect to the uncoupled excited molecule relaxation to the ground state.
Active nanophotonics can be realized by controlling the optical properties of materials with external magnetic fields. Here, we explore the influence of optical anisotropy on the magneto-optical ...activity in nonmagnetic hyperbolic nanoparticles. We demonstrate that the magneto-optical response is driven by the hyperbolic dispersion via the coupling of metallic-induced electric and dielectric-induced magnetic dipolar optical modes with static magnetic fields. Magnetic circular dichroism experiments confirm the theoretical predictions and reveal tunable magneto-optical activity across the visible and near infrared spectral range.
Protocells
Approximately 4 billion years ago, protocells are thought to have emerged as a precursor to life. In article number 2106624, Irep Gözen and co‐workers introduce protocell concepts, ...research and laboratory methods.
We report the formation, growth, and dynamics of model protocell superstructures on solid surfaces, resembling single cell colonies. These structures, consisting of several layers of lipidic ...compartments enveloped in a dome-shaped outer lipid bilayer, emerged as a result of spontaneous shape transformation of lipid agglomerates deposited on thin film aluminum surfaces. Collective protocell structures were observed to be mechanically more stable compared to isolated spherical compartments. We show that the model colonies encapsulate DNA and accommodate nonenzymatic, strand displacement DNA reactions. The membrane envelope is able to disassemble and expose individual daughter protocells, which can migrate and attach via nanotethers to distant surface locations, while maintaining their encapsulated contents. Some colonies feature "exocompartments", which spontaneously extend out of the enveloping bilayer, internalize DNA, and merge again with the superstructure. A continuum elastohydrodynamic theory that we developed suggests that a plausible driving force behind subcompartment formation is attractive van der Waals (vdW) interactions between the membrane and surface. The balance between membrane bending and vdW interactions yields a critical length scale of 236 nm, above which the membrane invaginations can form subcompartments. The findings support our hypotheses that in extension of the "lipid world hypothesis", protocells may have existed in the form of colonies, potentially benefiting from the increased mechanical stability provided by a superstructure.
Plasmon nanoantennas are extensively used with molecular systems for chemical and biological ultra-sensing, for boosting the molecular emissive and energy transfer properties, for nanoscale ...catalysis, and for building advanced hybrid nanoarchitectures. In this perspective, we focus on the latest developments of using plasmon nanoantennas for nanoscale chiral chemistry and for advancing molecular magnetism. We overview the decisive role nanoplasmonics and nano-optics can play in achieving chirally selective molecular synthesis and separation and the way such processes might be precisely controlled by potentially merging chirality and magnetism at the molecular scale. We give our view on how these insights might lead to the emergence of exciting new fundamental concepts in nanoscale materials science.
Here we report on nanoarchitectures composed of molecular magnets deposited on optical nanoantennas. We demonstrate a significantly boosted magneto-optical detection of a thin film of a terbium(
iii
...) bis-phthalocianinato (TbPc
2
) single-molecule magnet and we track down the origin of this enhancement to nanoantenna effects at the optical level. This finding suggests that the vast knowledge on plasmon-enhanced spectroscopies can be readily extended to magneto-optics, thus paving the way to strong magneto-optical enhancements for the readout of nanometric devices embedding single-molecule magnets.
Single-molecule magnets in hybrid architectures with plasmonic nanoantennas exhibit significant enhancement in their magneto-optical response.
Structural colour generation by nanoscale plasmonic structures is of major interest for non-bleaching colour printing, anti-counterfeit measures and decoration applications. We explore the physics of ...a two-metal plasmonic nanostructure consisting of metallic nanodiscs separated from a metallic back-reflector by a uniform thin polymer film and investigate the potential for vibrant structural colour in reflection. We demonstrate that light trapping within the nanostructures is the primary mechanism for colour generation. The use of planar back-reflector and polymer layers allows for less complex fabrication requirements and robust structures, but most significantly allows for the easy incorporation of two different metals for the back-reflector and the nanodiscs. The simplicity of the structure is also suitable for scalability. Combinations of gold, silver, aluminium and copper are considered, with wide colour gamuts observed as a function of the polymer layer thickness. The structural colours are also shown to be insensitive to the viewing angle. Structures of copper nanodiscs with an aluminium back-reflector produce the widest colour gamut.
Ultrafast Dynamics of Molecular Polaritons in Photoswitch Nanoantennas Kuttruff, Joel; Romanelli, Marco; Pedrueza-Villalmanzo, Esteban ...
2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC),
2023-June-26
Conference Proceeding
We study ultrafast dynamics of photocromic molecules both weakly and strongly coupled to plasmonic nanoantennas. Experiments, verified by quantum modelling, reveal subps collapse of molecular ...polaritons to intramolecular dynamics induced by interaction with the plasmons.
Bax is a key regulator of apoptosis that mediates the release of cytochrome c to the cytosol via oligomerization in the outer mitochondrial membrane before pore formation. However, the molecular ...mechanism of Bax assembly and regulation by other Bcl-2 members remains obscure. Here, by analysing the stoichiometry of Bax oligomers at the single-molecule level, we find that Bax binds to the membrane in a monomeric state and then self-assembles in <1 min. Strikingly, active Bax does not exist in a unique oligomeric state, but as several different species based on dimer units. Moreover, we show that cBid activates Bax without affecting its assembly, while Bcl-xL induces the dissociation of Bax oligomers. On the basis of our experimental data and theoretical modelling, we propose a new mechanism for the molecular pathway of Bax assembly to form the apoptotic pore.
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