Perovskite materials are at the forefront of modern materials science due to their exceptional structural, electronic, and optical properties. The controlled fabrication of perovskite nanostructures is crucial for enhancing their performance, stability, and scalability, directly impacting their applications in optoelectronic and sensing technologies. Here, we present a ligand-free and solvent-free approach to synthesize perovskite nanocrystals (NCs) with average sizes up to 100 nm, using femtosecond pulsed laser ablation (PLA) in ambient air without additional liquid media. We demonstrate this method for both organic-inorganic (methylamino lead) hybrid perovskites (MAPbX3, X = Cl, Br, I) and fully inorganic lead-free double perovskites (Cs2AgBiX6, X = Cl, Br), achieving high-purity NCs without stabilizing ligands - a critical advancement over conventional chemical synthesis methods. By tailoring laser parameters, we systematically elucidate the influence of perovskite composition (halide type, organic vs. inorganic cation, single vs. double perovskite structure) on the ablation process and the resulting nanocrystal properties. Transmission electron microscopy and Xray diffraction confirm the preservation of crystallinity, with MAPbX3 forming cubic NCs (similar to 90 nm) and Cs2AgBiX6 forming smaller, rounded NCs (similar to 10-15 nm). Photoluminescence spectroscopy reveals pronounced size-dependent spectral shifts (17-40 nm) due to quantum confinement, particularly for Br-and I-containing perovskites. Time-resolved photoluminescence measurements further reveal shortened decay times in laser-fabricated NCs compared to bulk crystals, indicating enhanced surface-and defect-assisted recombination. This solvent-free, scalable, and versatile PLA approach not only provides direct access to high-purity, ligand-free perovskite NCs with tunable optical properties but also represents a significant advance in the fabrication of nanostructures, enabling the further exploration of perovskite-based optoelectronic and quantum applications.

Even though metagenomics have revolutionized the characterization of the human microbiome, detailed mechanistic studies are impracticable, as there is a dearth of robust culture collections. We now describe the development and use of a laser-assisted culturomics platform, incorporating the elements of a bioprinter, the culture conditions, the methods to characterize the microorganisms and a biobank. With laser-assisted bioprinting, the microorganisms can be rapidly and precisely transferred from clinical biofilms to highly organized arrays of microbial colonies, which are suitable for co-culturing and molecular analyses. The presented technique has propagated 99 of 100 microbial species and recovered 79% of abundant species from dental plaque in accordance with full 16S rRNA gene profiling of 691,199 sequences. Microscopy, spectroscopy and enzyme assays have been used to guide isolations. Processing of oral biofilms from four individuals has yielded 249 representative isolates, from 14 classes and 124 species in total. Functional profiling with bioprinting has indicated commensals which could potentially contribute to disease development. Isolates from peri-implantitis cover 85.4% of the transcriptionally active clinical biofilms at genus level. Taken together, this work provides the basis for generating on-demand culture collections and biofilms for research and clinical use.

The development of non-toxic cryoprotectants is crucial for advancing fields such as regenerative medicine, cell therapy and tissue engineering, where the preservation of the viability of cells, tissues and organs during cryopreservation is essential. This interdisciplinary effort involves areas such as cryobiology, nanotechnology, biochemistry and material science to create more efficient and safer cryoprotective solutions. This study explores the development and application of gold nanoparticles (AuNPs) conjugated with antifreeze protein III (AFPIII) for improving the cryopreservation of bone marrow stem cells (bMSCs) encapsulated in alginate macrospheres (AMSs). Two types of AuNPs, stabilized with citrate (CitAuNPs) and BSPP (BSPPAuNPs), were functionalized with AFPIII using both covalent and non-covalent conjugation methods and were characterized for their size, surface charge and protein layer thickness. The cytotoxicity assays indicated that both types of AuNPs and their AFPIII conjugates had no adverse effects on bMSC viability and proliferation over 48 h, demonstrating their non-toxicity. Furthermore, the cryopreservation of bMSC-contained AMSs revealed that the covalent BSPPAuNPs-AFPIII conjugate provided superior preservation of cell viability and metabolic activity, outperforming both non-covalent conjugates and individual components. Cryomicroscopic analysis revealed that AFPIII altered ice crystal formation, promoting smaller, multidirectional crystals, which minimized cellular damage during freezing. The covalent BSPPAuNPs-AFPIII conjugate exhibited superior cryoprotective effects, preserving cell viability and function better than the non-covalent CitAuNPs-AFPIII conjugate. These findings suggest that AuNPs-AFPIII conjugates, particularly the covalent BSPPAuNPs-AFPIII complex, hold great promise for improving cell and tissue cryopreservation protocols.

There is a growing interest in lithium niobate (LN) as a material for integrated optics and metaphotonics. However, the limited strength of the electro‐optic effect remains a challenge for the realization of optical tunability in LN‐based nanophotonic systems. In this paper, a novel approach is introduced to enhance optical tuning. The proposed mechanism exploits the coupling between the photovoltaic effect induced in ferroelectric meta‐atoms under light illumination and a surrounding liquid crystal (LC) medium. Specifically, the LCs can be locally reoriented by the fringe photovoltaic fields generated by the meta‐atoms, whose spatially‐dependent dielectric anisotropy is modelled with a tensor approach. The LC re‐alignment in the vicinity of the meta‐atoms ultimately results in the self‐tuning of the metasurface optical response. The optical tuning of fundamental electric and magnetic metasurface resonances is numerically demonstrated via multiphysics simulations with and without the presence of an external voltage. This can result in high quality factor optical resonances, and their spectral shifts beyond what is achievable with the sole electro‐optic effect. For the first time to the authors' knowledge, the photovoltaic effect is introduced as a tuning strategy in dielectric metasurfaces, opening new opportunities for reconfigurable nanophotonic devices, such as light modulators, optical limiters, and optical sensors.

Quantum theory of photons based on the first quantization technique, similar to that used by Schroedinger in the formulation of quantum mechanics, is considered. First, scalar quantum mechanics of photons operating with the photon wave functions is discussed. Using the first quantization, the wave equation, the Schroedinger-like equations, and the Dirac equation for photons are derived. Then, vector quantum mechanics of photons is introduced, which defines the electromagnetic vector fields. Using the first quantization, the Maxwell equations for photons in magneto-dielectric medium are obtained. Since the photon electric and magnetic fields satisfy the Maxwell equations, all what is known about the classical optical fields can be directly transferred to photons demonstrating their quantum diversity. Relationships between the scalar and vector quantum mechanics of photons and between the Dirac and Maxwell equations are analyzed. To describe the propagation of photons in dispersive media novel equations are introduced.

Implant surface topography plays an important role in determining cell responses, including attachment, proliferation, migration, and differentiation. With rapid developments in micro-and nano-fabrication methods, precisely controlled patterns can be generated on implant surfaces. Osteon-mimetic structures are of great interest as new surface designs on bone implants for creating optimal conditions for bone tissue growth. In this work, we used a laser ablation technique to create a biomimetic relief on Ti-6Al-4 V supports. The osteonmimetic reliefs exhibited patterns of concentric lamellae-like rings of different width and periodicity. A distinctive feature of these reliefs is the presence of a highly porous nanocoating of titanium oxides, formed as a result of reverse deposition from the vapor-gas phase during ablation. Our investigation of the response of human mesenchymal stem cells revealed that the osteon-mimetic microrelief topography significantly influenced their adhesion, proliferation, and polarization. The presence of the nanocoating further impacted the number and localization of their focal adhesions. The outcomes of this work demonstrate an innovative direction towards the design of osteon-mimetic topographies on implantable materials. This work also holds the potential to identify optimal combinations of microrelief and nanocoating parameters to elicit specific cellular responses.

In recent years, nanotechnology has had a profound impact on low-temperature preservation, offering advanced solutions that significantly improve the storage of biological samples. Low-temperature preservation is crucial for numerous fields, such as medicine, agriculture, and biological research, where maintaining the viability and integrity of cells, tissues, and organs over extended periods is essential. Integration of nanotechnology into low-temperature preservation protocols represents significant advancement, enabling more effective, safer, and efficient storage of biological specimens. Moreover, it affords effective strategies for solving one of the most pressing challenges in transplantology and cryobiology today – cryopreservation of whole organs. This not only enhances the viability of cryopreserved materials but also broadens the scope of their applications in science and medicine. This article is a traditional review that summarizes the limitations of methods for the low-temperature storage of biological systems of animal origin and the current advances in nano-assisted technologies aimed at overcoming them. We have made every effort to accurately detail the role of inorganic nanoparticles in enhancing the field of cryobiology, paying special attention to their application in various methods of low-temperature preservation, specifically in hypothermic storage, slow-freezing cryopreservation, and vitrification. Finally, current challenges are critically assessed and perspectives are discussed.

The increasing demand for novel mirror coating designs for new generation of gravitational wave detectors is stimulating significant research interest in investigations of reflective properties of metasurfaces. Given this strong interest, this article details a systematic methodology for fabricating reflecting metasurfaces (metamirrors) designed to operate at target wavelengths of 1064 or 1550 nm. The proposed metasurfaces consist of silicon cylindrical nanoparticles placed on a sapphire substrate. First, the dimensional parameters of the structures are thoroughly selected through numerical simulations combined with material characterization. The configurations are subsequently analyzed analytically to reveal the mirror effect, which arises from the excitation of electric and magnetic dipole moments. Following this, the metasurfaces are fabricated and experimentally characterized, demonstrating reflectivity exceeding 95% around the design wavelengths, which is in good agreement with theoretical predictions. Overall, the work demonstrates the feasibility and detailed methodology for the fabrication of thin, lightweight metamirrors capable of achieving near‐perfect reflectivity at the specified target wavelengths.

Hypertrophic Cardiomyopathy (HCM) is often caused by heterozygous mutations in β-myosin heavy chain (MYH7, β-MyHC). In addition to hyper- or hypocontractile effects of HCM-mutations, heterogeneity in contractile function (contractile imbalance) among individual cardiomyocytes was observed in end-stage HCM-myocardium. Contractile imbalance might be induced by burst-like transcription, leading to unequal fractions of mutant versus wildtype mRNA and protein in individual cardiomyocytes (allelic imbalance). Until now it is not known if allelic and contractile imbalance are present early in HCM-development or rather occur in response to disease-associated remodeling.To address this question, we used patient-specific human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) with heterozygous MYH7-mutations R723G and G741R as models of early-stage HCM without secondary adaptions upon disease progression. R723G-hiPSC-CMs showed typical HCM-markers like hypertrophy and myofibrillar disarray. Using RNA-FISH and allele-specific single-cell-PCR, we show for both cell lines that MYH7 is transcribed in bursts. Highly variable mutant vs. wildtype MYH7-mRNA fractions in individual HCM-hiPSC-CMs indicated allelic imbalance. HCM-hiPSC-CM-lines showed functional alterations like slowed twitch contraction kinetics and reduced calcium sensitivity of myofibrillar force generation. A significantly larger variability in force generation or twitch parameters of individual HCM-hiPSC-CMs compared to WT-hiPSC-CMs indicated contractile imbalance.Our results with early-stage hiPSC-CMs strongly suggest that burst-like transcription and allelic imbalance are general features of CMs, which together with mutation-induced changes of sarcomere contraction could induce contractile imbalance in heterozygous CMs, presumably aggravating development of HCM. Genetic or epigenetic approaches targeting functional heterogeneity in HCM could lead to promising future therapies, in addition to myosin modulation.

This article explores the design and optimization of nanodisk metasurfaces for achieving high reflectivity at a defined wavelength. The telecom wavelength of 1550 nm is particularly focused, selected for its potential applications in next-generation gravitational wave detectors. At this wavelength, the research goes toward the development of thin, low-loss, high-reflective coatings, where the metasurface can be chosen as an alternative. An optimization process for the dimensional parameters of nanodisks is proposed based on a systematic tuning approach, which facilitates the realization of various configurations of high-reflective metasurfaces. The concept of the "magnetic mirror effect" is examined in detail, where the magnetic dipole resonance aligns with the anapole state. Additionally, high reflectivity at the electric dipole resonance ("electric mirror effect") and at the excitation of several multipole moments is explored, including high-order modes. This variety of configurations affords more flexibility in the phase manipulation of the reflected beam. Furthermore, the potential experimental realization of mirror effects is discussed by exploring the structure in the surrounding medium with a refractive index of nd = 1.4. This research platform provides a promising tool for the fabrication of high-reflective nanodisk metasurfaces and demonstrates its applicability across various fields. The paper proposes an optimization process for the dimensional parameters of silicon nanodisks based on a systematic tuning approach, which facilitates the realization of various configurations of high-reflective metasurfaces. The concepts of magnetic and electric mirror effects are considered, which provide information about the phase control of the reflected light field. image

Contrary to local resonances of single nanostructures, collective (or nonlocal) resonances in periodic metasurfaces, such as surface lattice resonances (SLRs), can significantly enhance light–matter interaction, leading to higher spectral selectivity. The dynamic control of such nonlocal response represents an emerging field of research. While tuning of SLRs has been demonstrated in plasmonic metasurfaces, the use of dielectric metasurfaces provides additional conditions to control both reflectance and transmittance, with minimum absorption effects. A close‐to‐homogeneous environment is usually required to guarantee the excitation of SLRs. Here, we propose theoretically and demonstrate experimentally a practical strategy for the tuning of SLRs in dielectric metasurfaces when an arbitrary index mismatch is considered between substrate and superstrate. The approach is based on a generalized lattice sum theory that accounts for the presence of a substrate. Dynamic tuning of the SLRs in silicon metasurfaces placed on a substrate is achieved with a changeable superstrate via an optofluidic process. Two tuning mechanisms are revealed corresponding to shifting and damping of the SLR, depending on the superstrate–substrate refractive index contrast. The demonstrated dynamic manipulation of transmission and reflection may be exploited in dielectric metasurfaces for tunable spectral selectivity, sensing, or novel display technologies.

Dynamic control of metamaterials and metasurfaces is crucial for many photonic technologies, such as flat lenses, displays, augmented reality devices, and beam steering, to name a few. The dynamic response is typically achieved by controlling the phase and/or amplitude of individual meta-atom resonances using electro-optic, phase-change or nonlinear effects. Here, we propose and demonstrate a new practical strategy for the dynamic control of the resonant interaction of light with dielectric metasurfaces, exploiting the dependence of the interaction between meta-atoms in the array on the inhomogeneity of the surrounding medium. The revealed tuning mechanisms are based on the concept of the surface lattice resonance (SLR), the development of which strongly depends on the difference between permittivities of superstrate and substrate materials. We experimentally demonstrate surface lattice resonances in dielectric (Si) metasurfaces, and reveal two tuning mechanisms corresponding to shifting or damping of the SLR in optofluidic environment. The demonstrated dynamic tuning effect with the observed vivid colour changes may provide a dynamic metasurface approach with high spectral selectivity and enhanced sensitivity for sensors, as well as high-resolution for small pixel size displays.

For a possible implementation of high-efficiency Si-nanosphere metasurface mirrors functioning at telecom wavelengths in future gravitational wave detectors, exact dimensional and configuration parameters of the total system, including substrate and protective coating, have to be determined a priori. The reflectivity of such multi-layer metasurfaces with embedded Si nanoparticles and their potential limitations need to be investigated. Here we present the results on how the substrate and protective layer influence optical properties and demonstrate how dimensional and material characteristics of the structure alter light reflectivity. Additionally, we consider the impact of manufacturing imperfections, such as fluctuations of Si nanoparticle sizes and their exact placement, on the metasurface reflectivity. Finally, we demonstrate how high reflectivity of the system can be preserved under variations of the protective layer thickness, incident angle of light, and its polarization.

The application of a pulsed laser ablation technique for the generation of cerium-doped garnet nanoparticles in liquids is investigated. The morphological and optical properties of the obtained nanoparticles are demonstrated. Features introduced by the single crystals of Gd3Al2.4Ga2.6O12:Ce3+, Lu3Al5O12:Ce3+, and Y3Al1.25Ga3.75O12:Ce3+ from which the nanoparticles are generated, as well as the parameters of a liquid media on the garnet nanoparticle generation are experimentally studied using TEM and UV-Vis spectroscopy methods. It is shown how the size, shape, and internal structure of the nanoparticles are related to the external laser ablation conditions, as well as to the laser melting processes of NPs in the colloidal solutions. This work provides important information about the generated nanoparticles, which can be used as building blocks for specially designed structures with predetermined optical properties.

Purpose:Microinvasive glaucoma surgery (MIGS) has become an important treatment approach for primary open-angle glaucoma, although the safe and long-term effective lowering of intraocular pressure with currently available implants for MIGS is not yet achieved to a satisfactory extent. The study focusses on the development and in vitro and in vivo testing of a novel microstent for MIGS.Methods:A silicone elastomer-based microstent was developed. Implants were manufactured using dip coating, fs-laser cutting, and spray coating. Within the current study no antifibrotic drug was loaded into the device. Sterilized microstents were analyzed in vitro regarding pressure-flow characteristics and biocompatibility. Six New Zealand white rabbits were implanted with a microstent draining the aqueous humor from the anterior chamber into the subconjunctival space. Drainage efficacy was evaluated using oculopressure tonometry as a transient glaucoma model. Noninvasive imaging was performed.Results:Microstents were manufactured successfully and characterized in vitro. Implantation in vivo was successful for four animals with additional device fixation. Without additional fixation, dislocation of microstents was found in two animals. Safe and effective intraocular pressure reduction was observed for the four eyes with correctly implanted microstent during the 6-month trial period.Conclusions:The described microstent represents an innovative treatment approach for MIGS. The incorporation of a selectively antifibrotic drug into the microstent drug-elutable coating will be addressed in future investigations.Translational Relevance:The current preclinical study successfully provided proof of concept for our microstent for MIGS which is suitable for safe and effective intraocular pressure reduction and offers promising perspectives for the clinical management of glaucoma.

For the first time to the best of our knowledge, CeAlO 3 nanocrystals with perovskite structure are synthesized by pulsed laser ablation technique. The morphological and optical properties of the obtained CeAlO 3 nanocrystals are investigated. This work opens new prospects for the application of laser ablation methods for the generation of perovskite nanocrystals and development of novel nanocomposite structures, which can be applied for the fabrication of perovskite solar cells, scintillation detectors, catalysts, etc.

Generation of human neuronal networks by three-dimensional (3D) bioprinting is promising for drug testing and hopefully will allow for the understanding of cellular mechanisms in brain tissue. The application of neural cells derived from human induced-pluripotent stem cells (hiPSCs) is an obvious choice, since hiPSCs provide access to cells unlimited in number and cell types that could be generated by differentiation. The questions in this regard include which neuronal differentiation stage is optimal for printing of such networks, and to what extent the addition of other cell types, especially astrocytes, supports network formation. These aspects are the focus of the present study, in which we applied a laser-based bioprinting technique and compared hiPSC-derived neural stem cells (NSCs) with neuronal differentiated NSCs, with and without the inclusion of co-printed astrocytes. In this study, we investigated in detail the effects of cell types, printed droplet size, and duration of differentiation before and after printing on viability, as well as proliferation, stemness, differentiation potential, formation of dendritic extensions and synapses, and functionality of the generated neuronal networks. We found a significant dependence of cell viability after dissociation on differentiation stage, but no impact of the printing process. Moreover, we observed a dependence of the abundance of neuronal dendrites on droplet size, a marked difference between printed cells and normal cell culture in terms of further differentiation of the cells, especially differentiation into astrocytes, as well as neuronal network formation and activity. Notably, there was a clear effect of admixed astrocytes on NSCs but not on neurons.

We demonstrate theoretically and experimentally dynamic tuning of optical response of dielectric metasurfaces based on the high-sensitivity of surface lattice resonances to their surrounding environment. This tuneability is achieved by controlling a dielectric permittivity contrast between the substrate and the superstrate, which leads to two different tuning mechanisms: a spectral shift or an on/off switching of surface lattice resonances. Experimentally, we demonstrate this tuning using an optofluidic platform combining a silicon metasurface on a glass substrate and a variable water level to control the refractive index of the superstrate and show a dynamic change of the optical response of the metasurface, manifested through change of its colouring. This concept may be applied for various applications, including high-resolution dynamic displays, sensing and anticounterfeiting protection.