Sensitive Luminescence Research Articles

Two new Zn(II) and Cd(II) coordination polymers derived from 1,3,5-tris(3-carbonylphenyloxy)benzene and 4,4′-bis(imidazolyl)biphenyl ligands: Syntheses, structure and luminescent sensing of antibiotics

Two new coordination polymers with formulae [Zn(HL)(bb)]n (1) and [Cd(HL)(bb)]n (2) (H3L = 1,3,5-tris(3-carbonylphenyloxy)benzene and bb = 4,4′-bis(imidazolyl)biphenyl) have been synthesized solvothermally and structurally characterized by elemental analysis, IR, single crystal X-ray diffraction and thermal analyses. Single crystal X-ray diffraction studies reveal that compounds 1 and 2 show similar three-fold interpenetrating 4-connected 2D framework structure with the sql topological net and the Schläfli symbol of {44·62} and are further extended into 3D supramolecular network by inter-molecular hydrogen bonding. Compound 1 have been used as turn-off luminescent sensor and displayed sensitive and selective luminescence sensing for nitrofurazone antibiotic (NFZ) with Ksv of 0.87 × 103 M−1 and 1.98 ppm limit of detection (LOD). The plausible mechanistic pathway for the detrioration in the luminescent intensity of 1 in presence of antibiotics have been explained with the help of theoretical calculations. The calculations indicated that the decline in fluorescence intensity of 1 was accredited to the electron/energy transfer as well as weak interactions operating between 1 and antibiotic.

Multiple lattice sites occupied AlTaO4:Cr3+ phosphor for luminescence ratiometric thermometry and NIR light source

Cr3+-doped near infrared (NIR) phosphors have promising applications in NIR light sources and optical temperature detection. The development of materials with high relative sensitivity and efficient broadband NIR luminescence is the key. In this paper, we report a new multifunctional NIR phosphor AlTaO4:Cr3+, which contains both narrow-band emission associated with 2Eg→4A2 g transition and broadband emission induced by the 4T2 g→4A2 g transition owing to Cr3+ occupies both AlO6 and TaO6 lattice sites. The R-line (2Eg→4A2 g) emission and its anti-Stokes phonon sideband emission follow the Boltzmann distribution, and the thermometer constructed accordingly reaches a maximum Sr of 1% K−1 at 110 K. Under 425 nm excitation, the broad emission band (FWHM = 200 nm) reaches maximum at 880 nm with an internal quantum efficiency of 62.8%. The NIR LEDs prepared with AlTaO4:Cr3+ confirm the application value in NIR light sources.

Spatio-temporal variation in quartz luminescence sensitivity in the coastal area of China

Quartz luminescence signals have been proven to be an effective index for identifying sediment provenance. The provenance of quartz minerals on typical sandy coasts along the east coast of China serves as important evidence for estuarine and coastal aeolian geomorphological processes in coastal zones. However, the temporal and spatial differences in the sensitivity characteristics of quartz grains on the east coast of China remain controversial owing to a lack of systematic analyses of coastal sediments. In this study, we present the thermoluminescence (TL) and optical luminescence (OSL) sensitivity of quartz minerals from core FN1 in the coastal area of Fujian Province, and the relative OSL sensitivity of quartz minerals obtained from Hebei, Fujian, Hainan, and Taiwan provinces. Our results indicate that (1) the OSL sensitivity values of quartz grains in the FN1 core are closely correlated with the mean grain size, electrical conductivity, potential of hydrogen, and end-member, suggesting that the change in luminescence sensitivity may be closely related to climate changes; specifically, cold climatic events during this period can cause significant fluctuations in the sensitivity; further, the percentage contents of fast, medium, and slow components are also different; (2) spatially, there are clear differences between the %FAST value of quartz grains from different sandy coasts; in these coastal dune samples, the %FAST value of the quartz grains during the Last Glacial Maximum (LGM) was significantly different from that of the quartz grains during the interglacial; thus, %FAST can be used to distinguish between glacial and interglacial samples; specifically, the sensitivity of quartz from the glacial dune was higher than that from the interglacial dune, and the sensitivity dispersion of quartz from the glacial as smaller than that from the interglacial coastal dune sand; and (3) the change in the luminescence sensitivity of quartz grains was ultimately controlled by the provenance change. In different geological periods, transgression, regression, and abrupt climate change trigger changes in the supply range of sources, which indirectly affects the sensitivity characteristics of quartz minerals. The spatial difference in quartz sensitivity in the eastern coastal area of China is mainly affected by the characteristics of quartz crystals and types of bedrock, which require further systematic study.

Solid-state electrochemiluminescence sensor of CQDs based on ZIFs electrospun carbon fiber for malathion detection

In this paper, a novel and simple electrochemiluminescent sensor of CQDs based on ZIFs electrospun carbon fiber was constructed for the detection of malathion. Carbon quantum dots (CQDs) was obtained by pyrolysis of citric acid at high temperature. ZIFs electrospun carbon fiber (ENCF-67) prepared by electrospinning combined with high temperature calcination adsorbed Au NPs to obtain ENCF-67@Au. And the sensor of Nafion/ENCF-67@Au/CQDs/GCE was constructed by sequentially modified CQDs, ENCF-67@Au and Nafion on the electrode surfaces. ENCF-67@Au was used as the fixation material of CQDs and accelerator of system because ENCF-67 had the advantage of large specific surface area and porosity. Nafion/ENCF-67@Au/CQDs/GCE obtained sensitive and stable electrochemical luminescence signal in PBS containing S2O82-. The addition of malathion enhanced the ECL signal of the sensor with a linear increase in the range of 1.0 × 10-12 − 1.0 × 10-7 M and the limit of detection 3.3 × 10-13 M (S/N = 3). The sensor had good selectivity for malathion, which provided a simple and sensitive method for the detection of malathion in fruits and vegetables in real life and had potential applications.

Towards the optically stimulated luminescence dating of unheated flint

Flint tools are important archaeological finds, but unheated specimens remain challenging to date. The optical luminescence properties of the microcrystalline flint differ from sedimentary quartz grains, and optically stimulated luminescence (OSL) has, therefore, only occasionally been used to date heated flint specimens. However, if OSL dating could be used on unheated samples, this should expand the number of dateable flint samples from the archaeological record. This study investigates the luminescence sensitivity to blue, green, and infrared stimulation in flints collected from four sites in eastern Denmark. While stimulations at each wavelength yielded some luminescence emissions, blue OSL provided the strongest emission, and subsequent investigations here focus on measurements using this signal. The shape of the decay curves and the photo-ionising cross-sections for the blue OSL signal components are similar between natural and irradiated OSL and are also comparable to decay curves from calibration quartz. Dose–response curves show characteristic doses of ∽400 Gy, and dose recovery tests demonstrate that a SAR protocol can recover laboratory doses. The measured laboratory fading rates are considerable, where flint slices stored for up to six weeks provide average g-values of up to 9 % per decade. Also, the flint is less thermally stable compared to calibration quartz. However, a natural OSL signal remains in Cretaceous flints (albeit at 50 % or less of laboratory saturation), showing that signal loss did not outpace the electron trapping rate. The presence of a dose-dependent, natural OSL signal and acceptable dose recovery indicate that optical dating of flint surfaces could be feasible, at least in the flints from eastern Denmark, and that flint from other regions should be investigated.

Luminescence fingerprints fluvial sediment transport from the Tibetan Plateau to the Bangladesh Delta

Fluvial sediment fingerprinting employs various methods, directly link sink and source. However, the identification and quantification of the transformation that sediments experience during fluvial transport remain unclear. The luminescence properties of quartz and K-feldspar change during the burial/exposure to sunlight cycles undergone by fluvial sediments, potentially allow scientists to trace fluvial sediment transport. Here, we report on changes in luminescence properties in active river bars from source to sink along the Yarlung Tsangpo-Brahmaputra River system. Optically stimulated luminescence (OSL) sensitivities and residual doses of quartz and K-feldspar within the fluvial sediments are used for the fingerprint method. Source rock is identified as the primary determinant of regional variations in quartz OSL sensitivities within fluvial sediments along the Yarlung Tsangpo River, while transportation distance governs local changes. Samples from narrower river channels with higher normalized channel steepnesses (Ksn) along the Yarlung Tsangpo River exhibit higher residual doses. Furthermore, the Brahmaputra River exhibits higher residual dose values compared to the Old Brahmaputra River. The sediments' residual doses are therefore employed to fingerprint fluvial erosion ability. Our luminescence fingerprint results indicate that coarse-grained fractions experience a “dilution” effect due to the input of new sediments after traveling approximately 50-200 km along the Yarlung Tsangpo River and about 50-100 km along the Brahmaputra-Old Brahmaputra River course. The comparison of luminescence (quartz and feldspar) and detrital zircon fingerprinting within the fluvial sediment holds the potential to trace weathering and erosion cycles during transportation in large river contexts.

Luminescence of rare earth 3D hydroxide framework Eu3+-doped and its application in dye adsorption tests

Rare-earth three-dimensional hydroxide frameworks ((Yb1-xLnx)3O(OH)6Cl.2H2O) were synthesized according to a previously published procedure, without modifications. The study of the structural behavior of these compounds against doping with Eu3+ ions showed that the replacement of 20% of Yb3+ by Eu3+ led to the formation of a lamellar structure. The maximum percentage of Eu3+ that can be included in the doping of the three-dimensional structure is 19%. Isophthalate was used as a luminescence sensitizer for the compounds and increased the quantum yield to 107 and 46% for the starting samples, doped with 10 and 20% of Eu3+, respectively. The lifetimes were adjusted to second order exponential decays for all samples, indicating the existence of two emitting centers. Samples were tested as adsorbents for methylene blue and methyl orange dyes in water. None of the samples showed positive results for the adsorption of methylene blue. For methyl orange, the lamellar sample showed promise. In preliminary tests, 10 mg of this sample managed to adsorb 70% of the dye present in 10 mL of a 10 mg L−1 methyl orange solution.

Synthesis of a lanthanide-based bimetallic-metal-organic framework for luminescence sensing anthrax biomarker

Lanthanide luminescence sensors have attracted extensive attention in the detection of 2, 6-pyridinedicarboxylic acid (DPA), the main biomarker of anthrax. In previous reports detecting DPA, luminescence probes may not have high selectivity and high specificity for identification. In the present study, a highly specific and sensitive luminescence probe was synthesized. In this paper, [TbxGd1-x (PBA)2NO3·2H2O]n is synthesized by solvothermal method using HPBA = 3.5-bis(triazol-1-yl)benzoic acid and Ln (NO3)3·6H2O (Ln = Tb, Gd). Through modulating the molar ratio of Tb3+ ions and Gd3+ ions, the distance between Ln3+ ions is changed, leading to a change in the energy transfer from the ligand to Tb3+, which in turn leads to an increase in luminescence intensity. Meanwhile the luminous colour is regulated by the ratio of Tb/Gd, which changes from green to white as the Gd ion gradually increases. The bimetallic ratiometric luminescence sensor realized accurate, high sensitivity (LOD is 1.03 × 10−6 M) and high selectivity detection of DPA. Due to the simple synthesis method and low technical requirements, this work provides a good strategy for the development of simple and effective bimetallic ratiometric luminescence sensors.

A multi-mode self-referenced optical thermometer based on low-doped YVO4: Eu3+ phosphor

In recent years, the continued development of optical thermometry has become a hot topic of interest for researchers, due to its advantages of non-contact and non-invasive temperature measurement. The optical thermometry is based on the different photophysical properties or changes in luminescent parameters of luminescent materials to reflect temperature. Further, the development of multi-mode optical thermometers can effectively expand the practical application rang of the temperature measurements. Here, we monitored various temperature sensitive luminescence characteristics of YVO4: Eu3+ phosphor by testing its temperature-dependent photoluminescence (PL) spectra, photoluminescence excitation (PLE) spectra, and luminescence decay curves. We successfully realized a multi-mode optical thermometer based on the luminescence intensity ratio, absorption intensity ratio, the thermally induced behavior of the charge transfer band, and luminescent transition probability (A) of the host material. Different temperature measurement strategies were evaluated and compared in terms of relative sensitivity (Sr) and temperature uncertainty (ΔT). Notably, the Sr of the rarely used temperature measurement strategy based on the A of host luminescence was the optimal among the studied strategies with 2.03% K−1, corresponding to a ΔT of 0.5 K. The results suggest that YVO4: Eu3+ phosphor has potential applications in self-referential optical thermometry.

Heterometallic ZnHoMOF as a Dual-Responsive Luminescence Sensor for Efficient Detection of Hippuric Acid Biomarker and Nitrofuran Antibiotics.

Developing efficient and sensitive MOF-based luminescence sensors for bioactive molecule detection is of great significance and remains a challenge. Benefiting from favorable chemical and thermal stability, as well as excellent luminescence performance, a porous Zn(II)Ho(III) heterometallic-organic framework (ZnHoMOF) was selected here as a bifunctional luminescence sensor for the early diagnosis of a toluene exposure biomarker of hippuric acid (HA) through "turn-on" luminescence enhancing response and the daily monitoring of NFT/NFZ antibiotics through "turn-off" quenching effects in aqueous media with high sensitivity, acceptable selectivity, good anti-interference, exceptional recyclability performance, and low detection limits (LODs) of 0.7 ppm for HA, 0.04 ppm for NFT, and 0.05 ppm for NFZ. Moreover, the developed sensor was employed to quantify HA in diluted urine samples and NFT/NFZ in natural river water with satisfactory results. In addition, the sensing mechanisms of ZnHoMOF as a dual-response chemosensor in efficient detection of HA and NFT/NFZ antibiotics were conducted from the view of photo-induced electron transfer (PET), as well as inner filter effects (IFEs), with the help of time-dependent density functional theory (TD-DFT) and spectral overlap experiments.

Host sensitization of luminescence of lanthanide activators in NaBi(WO4)2

The synthesis and luminescence of a series of NaBi(WO4)2 activated with trivalent lanthanides Tb, Sm and Nd using the solid-state reaction method is reported. All samples were characterised by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL). The XRD study confirmed the tetragonal phase without any secondary phase. Particles of irregular shape ranging between 5 and 20 µm were observed. Elemental composition was obtained from EDAX and results were found consistent with the formula NaBi(WO4)2. The formation of single-phase NaBi(WO4)2 was again confirmed through these results. Elemental mapping indicated that all elements were uniformly distributed. The band gap was evaluated using Tauc’s. formula and was found from 5.6 eV to 5.91 eV which is higher than reported values (3.6 eV). For NaBi(WO4)2:Tb, excitation was monitored for 545 nm emission. Emission spectra upon excitation by 488 nm showed prominent lines around 545 and 549 nm. These are due to the transition 5D4 7F5. 5 mol.% Tb yielded maximum PL intensity. When 405 nm excitation is used for Sm3+ doped phosphor, lines can be seen in three groups around 564, 600 and 647 nm. The highest emission intensity is observed for Sm3+ concentration of 5 mol.% and quenching was observed for high values. A weak band could be seen in the excitation spectra which is distinct from the f-f lines. The position of this band is close to that observed in the reflectance spectra. Hence it is proposed that there is host sensitization, even though weak, of the lanthanide luminescence in this host. Sensitization is most probably due to Bi3+ Ln3+ energy transfer.

Five Novel Silver-Based Coordination Polymers as Photoluminescent Sensing Platforms for the Detection of Nitrobenzene.

Nitrobenzene (NB) is a highly toxic chemical and a cause for concern to human health and the environment. Hence, it is worthwhile to design new efficient and robust sensing platform for NB. In this study, we present three newly synthesized luminescent silver cluster-based coordination polymers, {[Ag10(StBu)6(CF3COO)4(hpbt)] (DMAc)2(CH3CN)2}n (hpbt = N,N,N',N'N",N"-hexa(pyridine-4-yl)benzene-1,3,5-triamine), [Ag12(StBu)6(CF3COO)6(bpva)3]n (bpva = 9,10-Bis(2-(pyridin-4-yl)vinyl)anthracene), and {[Ag12(StBu)6(CF3COO)6(bpb)(DMAc)2(H2O)2] (DMAc)2}n (bpb = 1,4-Bis(4-pyridyl)benzene) composed of Ag10, Ag12 and Ag12 cluster cores, respectively, connected by multidentate pyridine linkers. Besides, two new luminescent polymorphic silver(I)-based coordination polymers, [Ag(CF3COO)(dpa)]n (dpa = 9,10-di(4-pyridyl)anthracene) referred to as Agdpa (H) and Agdpa (R), where H and R denote the hexagon-like and rod-like crystal shapes, respectively, have been prepared. The coordination polymers exhibit highly sensitive luminescence quenching effect to NB, attributed to the π-π stacking interactions between the polymers and NB as well as the electron-withdrawing character of NB.

Excitation Wavelength Engineering through Organic Linker Choice in Luminescent Atomic/Molecular Layer Deposited Lanthanide-Organic Thin Films.

We demonstrate multiple roles for the organic linker in luminescent lanthanide-organic thin films grown with the strongly emerging atomic/molecular layer deposition technique. Besides rendering the hybrid thin film mechanically flexible and keeping the lanthanide nodes at a distance adequate to avoid concentration quenching, the organic moieties can act as efficient sensitizers for the lanthanide luminescence. We investigate six different aromatic organic precursors in combination with Eu3+ ions to reveal that by introducing different nitrogen species within the aromatic ring, it is possible to extend the excitation wavelength area from the UV range to the visible range. This opens new horizons for the application space of these efficiently photoluminescent thin-film materials.

Enhanced detection of endocrine disrupting chemicals in on-chip microfluidic biosensors using aptamer-mediated bridging flocculation and upconversion luminescence

Exposure to endocrine-disrupting chemicals (EDCs) can lead to detrimental impacts on human health, making their detection a critical issue. A novel approach utilizing on-chip microfluidic biosensors was developed for the simultaneous detection of two EDCs, namely, bisphenol A (BPA) and diethylstilbestrol (DES), based on upconversion nanoparticles doped with thulium (Tm) and erbium (Er), respectively. From the perspective of single nanoparticles, the construction of an active core-inert shell structure enhanced the luminescence of nanoparticles by 2.28-fold (Tm) and 1.72-fold (Er). From the perspective of the nanoparticle population, the study exploited an aptamer-mediated bridging flocculation mechanism and effectively enhanced the upconversion luminescence of biosensors by 8.94-fold (Tm) and 7.10-fold (Er). A chip with 138 tangential semicircles or quarter-circles was designed and simulated to facilitate adequate mixing, reaction, magnetic separation, and detection conditions. The on-chip microfluidic biosensor demonstrated exceptional capabilities for the simultaneous detection of BPA and DES with ultrasensitive detection limits of 0.0076 µg L-1, and 0.0131 µg L-1, respectively. The first reported aptamer-mediated upconversion nanoparticle bridging flocculation provided enhanced luminescence and detection sensitivity for biosensors, as well as offering a new perspective to address the instability of nanobiosensors.

Structural, mechanical, dielectric and defect properties of Eu-doped BeO ceramics: A computational and experimental approach

BeO ceramics in the wurtzite (w-BeO) form either pure or doped with lanthanide ions present high Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) sensitivity. However, the mechanism of defect formation governing the charge carrier dynamics associated with the TL and OSL signals is not well understood yet. Thus, this work aims to develop a study on the structural, mechanical, dielectric, and defect properties of Europium ion–doped w-BeO ceramics. We develop a new set of potential parameters to describe the Be–O bond. By using these potential parameters, we describe the physical and chemical properties with good agreement. Defect calculations employing the Mott and Littleton two-region strategy show that the distorted structure of pure w-BeO ceramics favours the Frenkel–type defect formation in the basal plane of the crystal lattice. When doped with Eu3+, we observed a change in the defect arrangement. It replaces preferentially two Be sites, eliminating beryllium interstices and keeping the beryllium vacancy from the initial configuration. We also observed that it is unlikely the Eu3+/Eu2+ coexist due to the solution energy values. Lastly, we have observed a most significant electron–hole interaction which may be associated with the intrinsic luminescence band of the w-BeO ceramics. In addition, TL and OSL measurements are presented to corroborate the defect calculations. The results presented here bring new insight to elucidate the charge carrier dynamic associated with the luminescent properties.

A luminescence thermometer: temperature sensitive paint based on rare earth complexes and polymethyl methacrylate

Well-defined probes based on rare earth complexes were prepared by using europium oxide (Eu2O3), gadolinium oxide (Gd2O3), 2-thenoyl trifluoroacetone (TTA), and 1,10-phenanthroline monohydrochloride monohydricrate (phen) as raw materials. Fluorescence spectroscopy was used to determine that 1:1 is the optimal ratio of Eu3+ and Gd3+. So a Eu0.5Gd0.5(TTA)3phen/PMMA temperature sensitive paint was prepared composed of rare earth complexes Eu0.5Gd0.5(TTA)3phen as probe molecules and polymethyl methacrylate (PMMA) as the matrix. The as-prepared Eu0.5Gd0.5(TTA)3phen/PMMA exhibits a strong emission at 617 nm and has fine temperature quenching properties in the range of 20 °C–90 °C. Furthermore, the rate of change of luminescence and temperature sensitivity are enhanced due to doping of Gd3+, illustrating a synergistic effect between Gd3+ and Eu3+.

Investigating optical dating of carbonate-rich cobbles from a river terrace: A pilot study from the Mula Valley, Spain

Rock surface luminescence dating has emerged as a powerful geochronological tool; however, the method requires lithologies containing sufficient amounts of quartz or feldspar grains. The application of burial dating to fluvial cobbles, containing only sparse amounts of feldspars, is evaluated in calcarenite cobbles collected in the Mula valley, Spain. Two sampled cobbles demonstrated sufficient luminescence sensitivity. We extracted three or more drill cores from each cobble surface and subsequently measured the sensitivity-corrected luminescence signal with depth using an IRSL/pIRIR protocol to target feldspar grains in calcarenites. We observed significant luminescence-signal depth variations between the cores collected from the same rock surface, suggesting the value of measuring several cores. None of the top surfaces has been significantly bleached; therefore, they convey no relevant age data. Cores from the bottom surfaces show evidence of bleaching in the first 1 to 3 mm, but generally, only the surface slices can be used for dating. One core from each cobble displays a short, non-saturated dose plateau near the surfaces; the modelling demonstrates that the surface slices from these cores contained negligible doses before burial. The age estimate for the bottom surfaces mainly falls into two groups: 24–38 ka and 11–16 ka. The older age group is within the expected age range, previously dated with radiocarbon on another outcrop of the same terrace system. However, the signal-depth profiles indicate that the younger date is more reliable than the older date. Currently, no geomorphological explanation exists to explain the younger-than-expected ages.

Highly sensitive Fe3+ luminescence detection via single-ion adsorption

To achieve a lower detection limit has always been a goal of analytical chemists. Herein, we demonstrate the first picomolar level detection capability for Fe3+ ion via luminescence detection technology. The results of structural analysis and theoretical calculation show that Fe3+ ions are adsorbed on the central node of Eu-DBM (DBM = dibenzoylmethane) sensor in the form of single ion at ultralow concentration. Subsequently, the pathways of photo-induced charge and energy transfer of the obtained Eu-DBM@Fe3+ material have been changed, from the initial DBM-to-Eu3+ before Fe3+ adsorption to the ultimate DBM-to-Fe3+ after adsorption process, which quenches the luminescence of Eu3+ ion. This work not only obtains the highly sensitive luminescence detection ability, but also innovatively proposes the single-ion adsorption mechanism, both of which have important scientific and application values for the development of more efficient detection agents in the future.

Rational design of core-shell Ln-MOF hierarchitecture for ratiometric fluorescent sensing and bioimaging for phosphate or ATP

Mixed hierarchical lanthanide metal-organic framework (Ln-MOF) with core-shell structure has been acquired via a solution-mediated epitaxial growth method, retaining the spatially segregated structure of network and domain fluorescence property. The excellent heterostructured characteristics of Ln-MOFs enable the effective electron modulation, multiple energy transfer and thereby remarkably increase recognizing and sensing capacity in phosphate (Ps) or adenosine triphosphate (ATP). Ln3+ centers coupled with Ps or ATP could trigger a decrease in fluorescence of Ln3+, and further interrupt original fluorescence intensity ratio of Tb3+/Eu3+ (I545/I616) to shape the ratiometric fluorescent register. The optimized Tb/Eu-MOF with Tb/Eu ratio of 1:1 presented good linearity responsive to Ps and ATP with lower detection limit of 84.1 nM and 121.4 nM, respectively. Meanwhile, the interference and toxicity experiments have confirmed its high selectivity and high biocompatibility. Thus, the probe could be applied to detect Ps in real environmental water and biologically imaging ATP in Hela cells. This has provided a new strategy to construct Ln-system heterojunction with multiplexed luminescence selectivity and sensitivity in substance detection.

Monitoring of Geomagnetic Field Fluctuations with Luminescent Bacteria Photobacterium phosphoreum

In recent years, one of the important goals is to develop information systems for continuously monitoring the biological impact of the variable geomagnetic field. This problem is of importance from the viewpoint of forecasting such global processes as climate changes as well. Objective. This study is focused on monitoring the intensity of the luminescence of Photobacterium phosphoreum depending on the geomagnetic field fluctuations in an automated registration mode. Pilot studies were performed using the proposed automated system for recording changes in the bioluminescence of P. phosphoreum. Methods. P. phosphoreum UCM B-7071 bacteria were cultured in a liquid nutrient medium. The study of the influence of the geomagnetic field requires simultaneous automated long-term calculations in real time. For this, a complex for continuous cultivation of P. phosphoreum B-7071 bacteria was created. A program for information processing of bacterial luminescence datasets was developed. The data on geomagnetic field fluctuations from the Subbotin Institute of Geophysics NAS of Ukraine (the Subbotin IGPH) were synchronized with the period of registration of bioluminescence changes. Then the two datasets of the variables selected for chosen time intervals were processed. To evaluate the dependence of changes in the bacteria’s luminescence intensity on geomagnetic field fluctuations, the correlation coefficients of the obtained arrays of experimental data were calculated. Results. The results obtained show the sensitivity of the Photobacterium phosphoreum luminescence to fluctuations in the geomagnetic field. The used data sampling method made it possible to average the luminescence intensity values not only with 1-min resolution, but also with 1-hour, 3-hour, and other chosen resolutions. Conclusions. The analysis of changes in the luminescence intensity of P. phosphoreum bacteria due to geomagnetic field fluctuations, with input data being synchronized in time, revealed a positive correlation. Additional analysis is needed to obtain more essential evidence for the bioresponse to the impact of illustrative indicators of geomagnetic field stormy fluctuations. Actually, further analysis of luminescence intensity changes during large natural geomagnetic disturbances or via modeling of their action in the laboratory conditions is needed.