Photosensitive Component Research Articles

Photosensitive Nanoprobes for Rapid Isolation and Size-Specific Enrichment of Synthetic and Extracellular Vesicle Subpopulations.

The biggest challenge in current isolation methods for lipid bilayer-encapsulated vesicles, such as exosomes, secretory, and synthetic vesicles, lies in the absence of a unified approach that seamlessly delivers high purity, yield, and scalability for large-scale applications. To address this gap, we have developed an innovative method that utilizes photosensitive lipid nanoprobes specifically designed for efficient isolation of vesicles and sorting them into subpopulations based on size. The photosensitive component in the probe undergoes cleavage upon exposure to light, facilitating the release of vesicles in their near-native form. We demonstrate that our method provides superior capability in isolating extracellular vesicles from complex biological media and separating them into size-based subpopulations within 1 hour, achieving more efficiency and purity than ultracentrifugation. Furthermore, this method's cost-effectiveness and rapid enrichment of the vesicles align with demands for large-scale isolation and downstream analyses of nucleic acids and proteins. Our method opens new avenues in exploring, analyzing, and utilizing synthetic and extracellular vesicle subpopulations in various biomedical applications, including diagnostics, therapeutic delivery, and biomarker discovery.

Modular wearable optoelectronic system using photoactive nanomembranes

Ultrathin, flexible, cost-effective, and high-performance optoelectronic materials, such as halide perovskites and two-dimensional (2D) nanomembranes, have recently attracted significant attention in the field of wearable bio-integrated systems owing to their exceptional theoretical performance (e.g., high mechanical stability without significant degradation of electrical and optical properties) that may potentially surpass those of conventional rigid/brittle/bulky semiconductors under the condition of external mechanical stress applied. Despite the progress made at the individual unit level, the currently used fabrication/integration process does not satisfy the requirements established for personalized wearable optoelectronic systems because no reconfigurable heterogenous integration of various photoactive materials into a monolithic soft skin-like platform has been performed yet. Herein, we report a modular wearable optoelectronic system that exhibits a unique combination of energy harvesting, sensing, and display capabilities based on two different types of photoactive nanomembranes (halide perovskites and 2D semiconducting MoS2 nanosheets) even under on-skin deformation. To ensure that this system is reconfigurable both physically and electrically, we added a water-resistant self-healing stretchable polymer and conducting composite films to its encapsulation/substrate layers and interconnects, respectively. The spontaneous modularity that is inherent in self-healing materials enabled the formation of an integrated optoelectronic system with the following functional units. i) Photovoltaic and photoemissive devices containing perovskite-based nanomembranes were used as efficient power supplies and for immediate visualization, respectively. ii) A MoS2 nanosheet-based photosensitive component quantitatively distinguished various brightness conditions. iii) An integrated modular system was capable of detecting either tactile stimuli or various motions. The proposed integration strategy can be potentially utilized for realizing high-performance on-demand/user-defined wearable optoelectronic systems.

Effect of the Deposition of Vanadium-Oxide on the Photocatalytic Activity of TiO2 Nanotubes and Its Photodiode Performance Interfaced with CH3NH3PbI3 Single Crystal

In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO2 nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH3NH3PbI3. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs.

Nitrogen-doped carbon dots/curcumin nanocomposite for combined Photodynamic/photothermal dual-mode antibacterial therapy

Due to their excellent photophysical properties, carbon quantum dots have great potential in biomedical and drug delivery fields. In this study, nitrogen-doped carbon quantum dots with good water solubility were prepared using citric acid and ethylenediamine as precursors, and compounded with curcumin, a photosensitive component, to produce composite nanomaterials with photodynamic therapy and synergistic photothermal therapy. The formation of nitrogen-doped carbon quantum dots and composite nanomaterials was verified using physical and optical means. In addition, the composite nanomaterials produced single-linear oxygen and exacerbated the increase of solution temperature under blue (405 nm) and near-infrared (808 nm) light irradiation, respectively. The plate counting method showed that the composite nanomaterials exhibited good photodynamic synergistic photothermal antibacterial properties against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus under dual light source (405+808 nm) irradiation, which improved the photoinactivation of curcumin against bacteria. In addition, the composite nanomaterials exhibited low toxicity and good hemocompatibility. These experimental results suggested that the composite nanomaterials showed great potential in a multimodal photodynamic therapy synergistic photothermal treatment platform.

Recyclable and reprocessable epoxy-polyhedral oligomeric silsesquioxane (POSS)/mesogenic azobenzene/poly (ethylene-co-vinyl acetate) composites with thermal- and light-responsive programmable shape-memory performance

In this study, an Epoxy/POSS-liquid crystalline azobenzene-Poly (ethylene-co-vinyl acetate) (Epoxy/POSS-Azo-EVA) composite was prepared via the thermal curing of epoxy monomers and multi-functional thiol-containing Polyhedral oligomeric silsesquioxane (POSS) in an EVA matrix. The EVA matrix afforded the composite with shape memory performance. Epoxy/POSS polymer was uniformly dispersed in the matrix to act as a rigid skeleton, leading to the improvement of the mechanical properties and shape memory performance of the composite. Liquid crystalline azobenzene as the photosensitive component provided the inner stress to render the composite film with photo-induced shape-deformation behavior under UV light. The composite film not only exhibited thermal- and light-responsive programmable shape-memory behavior stimulated by heat and light, but also was recyclable and reprocessable. Moreover, the recycled composite film was processed into different functional devices. A flexible photomechanical device based on the recycled Epoxy/POSS-Azo-EVA composite film was fabricated, and the soft device deformed into a hook-shape under UV light and hooked an object whose weight is larger than that of the device. A smart wire was also prepared via assembling a stretched recycled Epoxy/POSS-Azo-EVA composite film and a copper foil by adhesive. The wire could control the status of a circuit via changing its shape under UV light and maintain the status after the removal of light. The functional devices described in this work only needed a short time of UV irradiation during a work cycle, and the devices still held the temporary shape in the absence of UV irradiation. The recyclable and reprocessable Epoxy/POSS-Azo-EVA composite film in this work could provide a creative approach for the fabrication of novel photomechanical devices and soft robotics with energy-saving, intelligence, recyclability, and sustainability.

Novel visible-driven Ag2O/Fe2O3/TiO2 nano sized hetero-structured photocatalyst: Synthesis, characterization and photo-degradation of tetracycline

Novel visible light respond Ag2O/Fe2O3/TiO2 nanocomposite was synthesized via impregnation assisted ultrasonic method. This nanocomposite showed impressive photocatalytic properties that can be used to remove the wide range of organic pollutants in order to wastewater treatment. Prepared nano photocatalyst was characterized using FE-SEM, EDX, XRD, DRS and PL analysis. FE-SEM images showed uniform spherical morphology with average particles size less than 16nm. Crystalline phases of synthesized nanocomposite observed through XRD analysis, including anatase, maghemite and Ag2O without any interfering substances. DRS results indicated that absorption spectra extended to visible-light region and effective separation of charge carriers was confirmed by PL spectra. Photocatalytic activity of prepared samples was investigated by tetracycline removal in contaminated water under visible light. The results showed high photo-degradation efficiency under visible light radiation about 90% in 90min. This result is attributed to synergic effect of Fe2O3 and Ag2O. Fe2O3 leads to narrow the band gap and decrease the charge carriers’ recombination, additionally, presence of Ag2O particles acts as a photosensitive component and formation of Ag-Ag2O structure causes the self-stability of photocatalyst.

Alkali Metal Salts of 10,12-Pentacosadiynoic Acid and Their Dosimetry Applications.

Wide-dose-range 2D radiochromic films for radiotherapy, such as GAFchromic EBT, are based on the lithium salt of 10,12-pentacosadiynoic acid (Li-PCDA) as the photosensitive component. We show that there are two solid forms of Li-PCDA—a monohydrated form A and an anhydrous form B. The form used in commercial GAFchromic films is form A due to its short needle-shaped crystals, which provide favorable coating properties. Form B provides an enhanced photoresponse compared to that of form A, but adopts a long needle crystal morphology, which is difficult to process. The two forms were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, CP-MAS 13C solid-state NMR spectroscopy, and thermogravimetric analysis. In sum, these data suggest a chelating bridging bidentate coordination mode for the lithium ions. The sodium salt of PCDA (Na-PCDA) is also reported, which is an ionic cocrystal with a formula of Na+PCDA–·3PCDA. The PCDA and PCDA– ligands display monodentate and bridging bidentate coordination to the sodium ion in contrast to the coordination sphere of the Li-PCDA forms. In contrast to its lithium analogues, Na-PCDA is photostable.

Three-state lithography model: an enhanced mathematical approach to predict resist characteristics in grayscale lithography processes

Background: Physical modeling of grayscale lithography processes for the prediction of photoresist heights leads to complex mathematical algorithms. A promiment example is the numerical simulation of the photoresist shape after development through Dill’s equations. These grayscale lithography models exhibit accurate prediction quality but can not directly implemented into mask layout tools to simplify the layout procedure. Limited process windows, changes in the mask design, variations of the used materials or manufacturing tools lead to time-consuming and cost-intensive test procedures to adjust the photoresist model for sufficient results. Aim: The focus of this work is to enhance current grayscale lithography models for a straightforward method with the same precise prediction of remaining photoresist heights to simplify the mask layout process. Moreover, we aim for an uncomplicated optimization of the model to minimize the empirical analysis necessary for its use. Approach: Based on experimental results, we deploy a sectionally defined mathematical expression that includes the theory of Fraunhofer diffraction and illumination-dependent activation of the photo-sensitive component and its solubility in developer. Results: We produced pyramidal, spherical and chess field structures with exposure doses of 3000 and 15 , 000 J / m2 on bare silicon substrates with 100-nm resolution and on silicon substrates with anti-reflective coatings, with accuracy as fine as 20 nm. Conclusion: The proposed three-state lithography model has been verified by experimental evaluation. It is able to operate in a wide process window and can be directly implemented in existing mask layout software. This model ensures a cost-efficient and precisely controlled production of three-dimensional topographies using grayscale lithography processes.

Radiation-Induced Processes in Diazoquinone–Novolac Resist Films under Irradiation with 60Co γ-Rays

The processes occurring under the irradiation of FP9120 diazoquinone–novolac resist films on silicon with 60Co γ-rays have been studied by attenuated total reflectance (ATR) FTIR spectroscopy. It has been found that a significant modification of the ATR spectra of the photoresist films was noticeable only at absorbed doses above 200 kGy, and it occurred due to the radiation-induced transformations of methyl, methylene, hydroxymethyl, and phenoxyl groups of phenol–formaldehyde resin and o-naphthoquinone diazide (a photosensitive component). At the same time, the ATR spectra exhibited no signs of the destruction of aromatic fragments in the resist at doses to 300 kGy. In the region of the stretching vibrations of C=O bonds, a decrease in the maximum intensity of a band at ~1700 cm–1 was observed upon irradiation with its simultaneous broadening and shift to the high-energy region by ~30 cm–1 due to a change in the nearest environment of the C=O group. An increase in the absorption band intensity at 1650 cm–1 indicated the accumulation of formaldehyde upon the γ-irradiation of the resist as a result of the fragmentation of hydroxymethyl residues in the phenol–formaldehyde resin.

Device for Measurements of Ultraviolet’s Power Radiation

The paper presents a technique for developing a device for measurements of power of ultraviolet (UV) radiation. The paper provides a brief analysis of existing approaches in the design of UV dosimeters. The rationale for the design of the dosimeter using an UV photodiode is given. The choice of a photodiode based on cadmium sulfide is made on the basis of the technological equipment existing in Ukraine, the level of development of technological modes that allow, at low technology costs, to obtain photodiodes with parameters not inferior to expensive foreign analogues based on materials of the A3B5 group and silicon carbide. The problems that were solved when developing a photodiode based on CdS and the original solutions found by the authors of the development are shown. The primary transducer is a photodiode based on the surface-barrier structure of p-Cu1.8S/n-CdS with a photosensitive component based on cadmium sulfide CdS. At a wavelength of λ ~ 250 nm, the sensitivity of p-Cu1.8S/n-CdS sensors is two times higher than GaP-based Schottky diodes. The value of the output current depends on the power of the UV radiation and lies within 0.0001-0.2 mA. The advantages of the developed sensor are the simplicity and low cost of the production technology, the ability to produce films of a large area, the characteristics of expensive foreign industrial UV photodiodes. The stages of development of the amplifier circuit for the selected photodiode are given. To design the amplifier circuit, the existing GUVA-S12SD UV Sensor V2 amplifier circuit was analyzed, and a custom circuit was developed with the following advantages: unipolar power; smaller potential difference between input and output compared to analog; different voltages are measured. The developed circuit uses the simplest resistive voltage divider, which is two series resistors connected to a voltage source. The scheme denominations were calculated. The sequence of printed circuit board (PCB) execution in the Sprint-Layout software environment is described. An image of the developed circuit board is shown. An analog-to-digital converter K1108PV1A is selected for signal processing from the amplifier and its technical characteristics are given. The block diagram of the dosimeter of energy illumination is offered: a photodiode, an amplifier of an input signal, an analog-to-digital converter, a microcontroller. As a microprocessor to be connected to the ADC, an electronic stand based on a microcontroller will be used to debug programs using ATmega16A. The obtained circuit solutions for the construction of a UV dosimeter based on a CdS photodiode can be used to quickly create an industrial device that will be an integral part of the complexes for disinfecting the metro and other rooms from viral infections.

A thermo and photoresponsive dual performing hydrogel for multiple controlled release mechanisms

A hydrogel with dual thermo and photoresponsive characteristics was developed. Using poly(N-isopropylacrylamide) (PNIPAM) as the thermosensitive unit, the hydrogel network can undergo reversible swelling/shrinking behavior under different temperatures (20 °C and 37 °C) stimulation. A supramolecular host–guest complex composed of azobenzene (Azo) and α-cyclodextrin (α-CD) was used as the photosensitive unit. Azo and α-CD can undergo reversible recombination/dissociation behavior under the stimulation of different wavelengths of light (365 nm and 430 nm). Methylene blue (MB) was selected as the model drug to measure the controlled release behavior of the hydrogel under different temperatures and photoirradiations. The experimental results showed that the hydrogel containing the thermosensitive component (PNIPAM) and the photosensitive component (α-CD/Azo) released 69.3% and 47.2% of MB at 20 °C and 37 °C, respectively. Under the condition of light wavelengths at 430 nm and 365 nm, 73.2% and 65.6% of MB were released, respectively. The results showed that α-CD and Azo formed a supramolecular host–guest complex, which could undergo reversible binding/dissociation under the action of light stimulation, thereby controlling MB to enter and exit CD cavity. In addition, when the ambient temperature was lower or higher than the lower critical solution temperature of PNIPAM (LCST, 32 °C), the hydrogel underwent a responsive volume change to control the loading and release of MB molecules. So, combining the dual thermo and photoresponsibility, this smart hydrogel could be applied for multiple controlled release mechanisms.

Composite Ferroelectric Coatings Based on a Heat-Resistant Polybenzoxazole Polymer Matrix

The polycondensation of 5,5-methylene bis(2-aminophenol) and the mixture of diamines 5,5-methylene bis(2-aminophenol) and 4,4-(hexafluoroisopropylidene)dianiline (molar ratio 0.8:0.2) with isophthaloyl dichloride was used to synthesize a new heat resistant binder of the composites for microelectronics: poly(o-hydroxyamide) (POA) and poly(amido-o-hydroxy amide) (POA-F). The thermal stability of synthesized polymer coatings, as well as based on them photosensitive compositions with a naphthoquinondiazide photosensitive component were studied in the temperature range from 100 to 500 °C. Ferroelectric composites with nanodispersed lead titanate zirconate powder filler were formed based on these polymer matrices. By manipulating the conditions of the polymer formation, we obtained matrices with different stiffnesses, which reflected on the properties of the composite. The electrophysical parameters of the synthesized polymer and ferroelectric composite coatings were measured in the frequency range from 0.1 Hz to 1.5 GHz and the temperature range from 0 to 300 °C. The frequency and temperature stability of the dielectric constant of ferroelectric composite coatings up to 10 MHz and 300 °C, respectively, are noted. The influence of the composition and structure of the polymer matrix and the grain/matrix interfaces on the thermal stability of the dielectric parameters of composite films is estimated. The shift of the phase transition region toward higher temperatures in the composite structure, as well as the sufficient rigidity of the poly(benzoxazole) matrix, provide high temperature and frequency stability of the dielectric constant of the studied composites.

Photovoltaic properties of InP NWs/p-Si heterostructure

The experimental and modelling results of the investigation of photovoltaic properties of the InP nanowires grown on p-Si substrate are presented. It is shown that InP 2D-layer between nanowires on Si is II-type heterojanction. The resulting structure exhibits an open-circuit voltage (Voc) of 0,37 V, a short-circuit current density (Jsc) of 10.6 mA/cm2, a fill factor (FF) of 0.61 and efficiency of 2.4% at 1 sun. The InP/p-Si structure can be applied as prototype for solar cells or the photosensitive component in an integrated circuit based on silicon technology.

The Radiation Detection Equipment Comprising the Sensor Matrix

The present article describes the technical design of a sensory system used for the detection and localisation of radiation direction in space using a photosensitive component, a sensor matrix. At present, there are a number of systems that use accumulated solar energy. The solar energy is used in heating systems, for water heating, as well as technological purposes and production of electrical energy. The most frequent applications include heating drinking water and energy accumulation in form of a usable (perceivable) heat in hot water containers. However, there are still certain limitations to these systems, as to heating and seasonal accumulation purposes, in terms of their efficiency and financial return.

Fabrication of nanocellulose/PEGDA hydrogel by 3D printing

PurposeNanocellulose is characterised by favourable biocompatibility, degradability, nanostructure effect, high modulus and high tensile strength and has been widely applied in various fields. The current research in the field of new nanocellulose materials mainly focuses on the hydrogel, aerogel and the tissue engineering scaffold. All of these are three-dimensional (3D) porous materials, but conventional manufacturing technology fails to realise precise control. Therefore, the method of preparing structural materials using 3D printing and adopting the nanocellulose as the 3D printing material has been proposed. Then, how to realise 3D printing of nanocellulose is the problem that should be solved.Design/methodology/approachBy adding the photosensitive component polyethyleneglycol diacrylate (PEGDA) in the aqueous dispersion system of nanocellulose, the nanocellulose was endowed with photosensitivity. Then, nanocellulose/PEGDA hydrogels were prepared by the additive manufacturing of nanocellulose through light curing.FindingsThe results showed that the nanocellulose/PEGDA hydrogels had a uniform shape and a controllable structure. The nanocellulose supported the scaffold structure in the hydrogels. Prepared with 1.8 per cent nanocellulose through 40 s of light curing, the nanocellulose/PEGDA hydrogels had a maximum compression modulus of 0.91 MPa. The equilibrium swelling ratio of the nanocellulose/PEGDA hydrogel prepared with 1.8 per cent nanocellulose was 13.56, which increased by 44 per cent compared with that of the PEGDA hydrogel without nanocellulose.Originality/valueThe paper proposed a method for rapidly prototyping the nanocellulose with expected properties, which provided a theoretical basis and technological reference for the 3D additive manufacturing of nanocellulose 3D structure materials with a controlled accurate architecture.

Nonlinear absorption and refraction studies of truncated CuNb3O8 with high-repetition rate femtosecond pulses

Copper niobate with CuNb3O8 composition was prepared via one-step solid state reaction (750 °C, 12 h). Powder X-ray diffraction (XRD) confirmed the formation of parental CuNb2O6 phase with traces of CuNb3O8 on initial sintering (till 9 h), which was then transformed into pure CuNb3O8 on higher sintering (12 h). Field emission scanning electron microscope studies (FESEM) illustrates the formation of truncated cubes due to unification of layered structure upon prolonged heating. Third-order nonlinear optical properties of truncated CuNb3O8 was studied by Z-scan technique using Ti: Sapphire laser (800 nm, 150 fs, 80 MHz). Pure CuNb3O8 possessed strong nonlinear absorption (two-photon absorption coefficient of 5.3 × 10−10 m/W) and nonlinear refractive index n2 (2.1 × 10−16 m2/W) compared to mixed copper niobate (CuNb2O6 - CuNb3O8). The third-order nonlinear optical susceptibility of CuNb3O8 was ∼10−11 esu and was higher than the known nonlinear optical (NLO) systems such as lithium niobate and sodium niobate measured at similar pulse duration. Enhancement in nonlinearity arises due to the influence of morphology and here truncated cubes with the platonic solids offer high polarizability as the charges are concentrated in the edges of the system. The truncated cube CuNb3O8 exhibited strong optical limiting action with a low limiting threshold (34.6 μJ/cm2), thus making it appealing for ultrafast optical limiter devices towards photosensitive component protection from Infrared (IR) laser damage.

Light-activated protein interaction with high spatial subcellular confinement

Methods to acutely manipulate protein interactions at the subcellular level are powerful tools in cell biology. Several blue-light-dependent optical dimerization tools have been developed. In these systems one protein component of the dimer (the bait) is directed to a specific subcellular location, while the other component (the prey) is fused to the protein of interest. Upon illumination, binding of the prey to the bait results in its subcellular redistribution. Here, we compared and quantified the extent of light-dependent dimer occurrence in small, subcellular volumes controlled by three such tools: Cry2/CIB1, iLID, and Magnets. We show that both the location of the photoreceptor protein(s) in the dimer pair and its (their) switch-off kinetics determine the subcellular volume where dimer formation occurs and the amount of protein recruited in the illuminated volume. Efficient spatial confinement of dimer to the area of illumination is achieved when the photosensitive component of the dimerization pair is tethered to the membrane of intracellular compartments and when on and off kinetics are extremely fast, as achieved with iLID or Magnets. Magnets and the iLID variants with the fastest switch-off kinetics induce and maintain protein dimerization in the smallest volume, although this comes at the expense of the total amount of dimer. These findings highlight the distinct features of different optical dimerization systems and will be useful guides in the choice of tools for specific applications.

Photo-Induced Bending Behavior of Post-Crosslinked Liquid Crystalline Polymer/Polyurethane Blend Films.

Photoresponsive blend films with post-crosslinked liquid crystalline polymer (CLCP) as a photosensitive component and flexible polyurethane (PU) as the matrix are successfully fabricated. After being uniaxially stretched, even at low concentration, the azobenzene-containing CLCP effectively transfers its photoresponsiveness to the photoinert PU matrix, resulting in the fast photo-induced bending behavior of whole blend film thanks to the effective dispersion of CLCP. Specifically, the blend film shows photo-induced deformations upon exposure to unpolarized UV light at ambient temperature. The film unbends after thermal treatment, and the randomly orientated mesogens in the film can be realigned by the mechanical stretching, which endows the film with a reversible deformation behavior. The photosensitive blend film possesses favorable mechanical property and good processability at low cost, and it is a promising candidate for a new generation of actuators.

Structural, thermal, optical and nonlinear optical properties of ethylenediaminium picrate single crystals

A new organic optical limiting material, ethylenediaminium picrate (EDAPA) was synthesized through acid base reaction and grown as single crystals by solvent evaporation method. Single crystal XRD analysis showed that EDAPA crystallizes in orthorhombic system with Cmca as space group. The formation of charge transfer complex during the reaction of ethylenediamine and picric acid was strongly evident through the recorded Fourier Transform Infra Red (FTIR), Raman and Nuclear Magnetic Resonance (NMR) spectrum. Thermal (TG–DTA and DSC) curves indicated that the material possesses high thermal stability with decomposition temperature at 243°C. Optical (UV–Visible-NIR) analysis showed that the grown crystal was found to be transparent in the entire visible and NIR region. Z-scan studies with intense short pulse (532nm, 5ns, 100µJ) excitations, revealed that EDAPA exhibited two photon absorption behaviour and the nonlinear absorption coefficient was found to be two orders of magnitude higher than some of the known optical limiter like Cu nano glasses. EDAPA exhibited a strong optical limiting action with low limiting threshold which make them a potential candidate for eye and photosensitive component protection against intense short pulse lasers.

How seaweeds release the excess energy from sunlight to surrounding sea water.

We report an atomistic insight into the mechanism regulating the energy released by a porphyra-334 molecule, the ubiquitous photosensitive component of marine algae, in a liquid water environment upon an electron excitation. To quantify this rapidly occurring process, we resort to the Fourier analysis of the mass-weighted auto-correlation function, providing evidence for a remarkable dynamic change in the number of hydrogen bonds among water molecules and between the porphyra-334 and its surrounding hydrating water. Hydrogen bonds between the porphyra-334 and close by water molecules can act directly and rather easily to promote an efficient transfer of the excess kinetic energies of the porphyra-334 to the surrounding solvating water molecules via an activation of the collective modes identified as hydrogen-bond stretching modes in liquid water which eventually results in a disruption of the hydrogen bond network. Since porphyra-334 is present in seaweeds, aquatic cyanobacteria (blue-green algae) and red algae, our findings allow addressing the question how algae in oceans or lakes, upon sunlight absorption, can release large amounts of energy into surrounding water without destabilizing neither their own nor the H2O molecular structure.