Blue Light Research Articles

Acoustic cavitation assisted synthesis of PCDs@PVA composite film for UV shielding, intelligent pH detection, information encryption and food packing applications

Excessive exposure to UV and high-energy blue light (HEBL) can severely damage the skin and eyes. Therefore, it is essential to protect our bodies from UV and HEBL radiation. We created PEG-derived carbon dots (PCDs) using the acoustic cavitation approach in order to completely block UV and HEBL. The influence of different experimental parameters such as sonication time, amplitude, and temperature on the PCDs is examined. The optimized PCDs are found to have an average diameter ranging from 5 to 9 nm, contingent upon the preparation circumstances, and to have a quantum yield (QY) of 14–16 %. The PCDs vivid colour and simultaneous UV and HEBL absorption properties allowed the PVA film containing 0.120 wt% of PCDs to demonstrate outstanding blocking efficiency, with 99.9 % blocking in HEBL and 100 % blocking in UV-C, UV-B, and UV-A. The photoluminescence (PL) behaviour of PCDs is greatly reduced by Fe3+ ions because of strong excited state electron transfer. This fluorescent “turn-off” behaviour towards Fe3+ is highly selective and sensitive with a limit of detection (LoD) of 0.366 μM. Paper-based sensors incorporating PCDs are developed for the rapid and accurate detection of Fe3+ in surface water, wastewater treatment plant effluent, and tap water, leveraging their excellent sensitivity and selectivity towards Fe3+. The characteristics of ink-free patterned substrates are displayed by PCDs scattered across a PVA matrix, which makes them useful for the non-destructive acquisition and recognition of latent fingerprints (LFPs). A flexible, transparent film is produced when a LFP is exposed to a PCDs@PVA solution. In this film, a steady luminous fingerprint with specific ridge characteristics that aid in personal recognition is seen. This method shows promise for lifting and identifying long-exposed LFPs from various surfaces without causing damage. It is believed that the interfacial segregation of PCDs inside the PVA matrix during the film production process serves as a mechanism for LFP collection and visualization. The YOLOv8x program, which utilizes deep convolutional neural networks, is employed to analyze the discernible features present in fingerprints (FPs). Notably, their exceptional flexibility, foldability, and sustainability create new opportunities for use in the anti-counterfeiting (AC) field. Because of its remarkable fluorescence stability, it may be a viable substitute for conventional fluorescent inks. Fresh green apples are observed over time after being coated with 0.120 wt% PCDs@PVA and PVA. Virtual assessments indicated that the 0.120 wt% PCDs@PVA film coating significantly reduced weight and moisture loss, effectively inhibiting fungal growth and spoilage for over 25 days at room temperature (RT). Overall, the results clearly show that the PCDs@PVA film is easy to make, flexible, safe for the environment, and resistant to photodegradation. Hemolysis, and blood clotting exhibited favorable biocompatibility and nontoxicity.

Droplet-Based Microfluidic Photobioreactor as a Growth Optimization Tool for Cyanobacteria and Microalgae

Microalgae and cyanobacteria are photosynthetic microorganisms with significant biotechnological potential for the production of bioactive compounds, making them a promising resource for diverse industrial applications. This study presents the development and validation of a modular, droplet-based microfluidic photobioreactor (µPBR) designed for high-throughput screening and cultivation under controlled light conditions. The µPBR, based on polytetrafluoroethylene (PTFE) tubing and a 4-channel LED illumination system, enables precise modulation of light intensity, wavelength, and photoperiod, facilitating dose–response experiments. Synechococcus elongatus UTEX 2973 and Chlorella vulgaris were used to demonstrate the system’s capacity to support photosynthetic growth under various conditions. The results indicate that continuous illumination, particularly under blue and mixed blue-red light, promotes higher autofluorescence and chlorophyll a content in cyanobacteria Synechococcus elongatus UTEX2973, while Chlorella vulgaris achieved optimal growth under a 16:8 light-dark cycle with moderate light intensity. This µPBR offers not only a flexible, scalable platform for optimizing growth parameters but also allows for the investigation of highly resolved dose response screenings of environmental stressors such as salinity. The presented findings highlight its potential for advancing microalgal biotechnology research and applications.

A Paradox of LED Road Lighting: Reducing Light Pollution Is Not Always Linked to Energy Savings

A variety of LED types can be employed for street and road lighting purposes. White phosphor-converted LEDs represent the most widely used option. However, amber LEDs are increasingly being used to reduce some negative effects associated with light pollution. These LEDs can be manufactured using both phosphor-converted and monochromatic direct chip technologies. This paper addresses the link between the reduction in short-wavelength light emissions which contribute to sky glow and the energy efficiency of LED-based road lighting. This paper focuses on an example illustrating the common misconception that reducing light pollution also means saving energy. Through the consideration of how spectral power distribution influences both mesopic vision and the amount of emitted blue light, it has been concluded that while monochromatic direct amber LEDs consume more energy than their white or amber phosphor-converted counterparts, their use in outdoor lighting is justifiable due to their potential effects of reducing sky brightness.

Spatiotemporal control of subcellular O-GlcNAc signaling using Opto-OGT.

The post-translational modification of intracellular proteins through O-linked β-N-acetylglucosamine (O-GlcNAc) is a conserved regulatory mechanism in multicellular organisms. Catalyzed by O-GlcNAc transferase (OGT), this dynamic modification has an essential role in signal transduction, gene expression, organelle function and systemic physiology. Here, we present Opto-OGT, an optogenetic probe that allows for precise spatiotemporal control of OGT activity through light stimulation. By fusing a photosensitive cryptochrome protein to OGT, Opto-OGT can be robustly and reversibly activated with high temporal resolution by blue light and exhibits minimal background activity without illumination. Transient activation of Opto-OGT results in mTORC activation and AMPK suppression, which recapitulate nutrient-sensing signaling. Furthermore, Opto-OGT can be customized to localize to specific subcellular sites. By targeting OGT to the plasma membrane, we demonstrate the downregulation of site-specific AKT phosphorylation and signaling outputs in response to insulin stimulation. Thus, Opto-OGT is a powerful tool for defining the role of O-GlcNAcylation in cell signaling and physiology.

Detection of Potato Pathogen Clavibacter sepedonicus by CRISPR/Cas13a Analysis of NASBA Amplicons.

The ring rot of potato caused by the bacterial pathogen Clavibacter sepedonicus is a quarantine disease posing a threat to the potato industry worldwide. The sensitive and selective detection of C. sepedonicus is of a high importance for its effective control. Here, the detection system is reported to determine viable bacteria of C. sepedonicus in potato tubers, based on the coupling of CRISPR/Cas13a nuclease with NASBA (Nucleic Acid Sequence Based Amplification)-the method of isothermal amplification of RNA. Detection can be conducted using both instrumental and non-instrumental (visual inspection of test tubes under blue light) modes. When NASBA and Cas13a analyses were carried out in separate test tubes, the limit of detection (LOD) for the system was 1000 copies of purified target 16S rRNA per NASBA reaction or about 24 colony-forming units (CFUs) of C. sepedonicus per 1 g of tuber tissue. The testing can also be conducted in the "one-pot" format (a single test tube), though with lower sensitivity: LOD was 10,000 copies of target RNA or about 100 CFU per 1 g of tuber tissue for both instrumental and visual detection modes. The overall time of NASBA/Cas13a analysis did not exceed 2 h. The developed NASBA/Cas13a detection system has the potential to be employed as a routine test of C. sepedonicus, especially for on-site testing.

Monochromatic light effects on refractive error, cone cell density and retinoic acid signaling in dorsal and ventral retina in guinea pigs

Cone cells have been found to influence refractive states. This study investigated whether cone cells and retinal acid (RA) plays a role in refractive states under monochromatic lights. Guinea pigs were exposed to blue (BL), green (GL), or white light (WL), respectively, for 8 weeks. Refractive error (RE), cone cell density, RA, retinoic acid receptor-β (RAR-β), collagen-I expression, and scleral thickness in dorsal and ventral eyes were assessed. Eyes exposed to BL showed a slower shift from hyperopia to emmetropia, particularly in the ventral retina, where higher S-cone density was linked to greater remaining hyperopia. In contrast, GL exposure led to myopic shifts, notably in the dorsal retina, where increased M-cone density was associated with greater reductions in refractive error. BL exposure resulted in similar decreases in RA and retinoic acid receptor-β (RAR-β) expression in both dorsal and ventral regions, along with elevated scleral collagen-I and thicker sclera. In contrast, GL exposure increased RA and RAR-β levels, while reducing scleral collagen-I and thickness. GL-associated changes in RAR-β expression and scleral thinning were more pronounced in the dorsal retina compared to the ventral retina, despite similar RA levels in both regions. These findings suggested that RA may not contribute to the hyperopic shifts with increased S-cone cell density in BL. However, increased RA and RAR-β may be correlated with ocular growth in guinea pigs exposed to GL, it may underlie myopic shifts with increased M-cone cell density.

Long-Lived Room-Temperature Phosphorescence from Silica Nanoparticles with In Situ Generated Carbonaceous Defects for Blue Organic Light-Emitting Diodes.

In this study, in situ formed silica nanoparticles (SNPs) emitting second-level phosphorescence at room temperature without a phosphorescent dopant have been achieved for the first time. This phosphorescence is achieved through the simple in situ formation of carbonaceous defects (CDs) within the SNPs, followed by passivation of the CDs by a robust silica matrix. The CD in the SNPs, termed CD@SNPs, are synthesized by cross-linking tetraethyl orthosilicate (TEOS) and (3-aminopropyl)triethoxysilane (APTES), and these cross-linked components create a porous structure within the silica matrix. Upon calcination, the carbon-related structures within the pores deform, leading to the formation of CDs. Confined within a robust silica matrix, the molecular motion of the CD is restricted, facilitating the generation of a stable triplet state and suppressing nonradiative decay. Moreover, the robust silica matrix passivates the CD confined in the SNPs at a nanoscale. These comprehensive effects enable prolonged phosphorescence emission from the SNPs. In addition, these phosphorescence-emitting SNPs have been applied as dopants in the emissive layer of organic light-emitting diodes to realize blue light emission. This feature suggests the possibility of utilizing luminescent SNPs as light emitters in display technologies.

Far-Red Light Inhibits Soybean Biomass and Yield by Modulating Plant Photosynthesis

Alterations in the light environment can significantly influence soybean morphology and yield formation; however, the effects and mechanisms of different light qualities on these aspects require further investigation. Consequently, we selected soybean cultivars with marked differences in light sensitivity as test materials, conducted experiments with red, blue, and green light qualities against a blue light background, and analyzed parameters related to leaf photosynthetic capacity, chlorophyll fluorescence, morphological characteristics, biomass, and yield variations following different light quality treatments. The results showed that following far-red light treatment, soybean plants exhibited significant shade avoidance syndrome, internode elongation, increased plant height, and a marked reduction in both root and leaf biomass, as well as total biomass. Furthermore, there was a substantial reduction in photosynthetic capacity. This indicated that far-red light exerts an inhibitory effect on soybean growth and yield formation. Red light has basically no regulatory effect on plant morphology and yield, while green light has a yield-increasing effect, but there was a cultivar effect. This study not only enhances our understanding of the mechanisms through which light quality regulates plant photosynthesis but also lays a scientific foundation for future crop light environment management and for the further exploration of light quality’s regulatory potential on crop growth.

DESIGN OF A PORTABLE PHOTOTHERAPY UNIT FOR HYPERBILIRUBINEMIA USING SURFACE MOUNTING DEVICE LIGHT EMITTING DIODES

Hyperbilirubinemia is a condition of a high bilirubin level in newborns causing a yellowish color on newborns’ skin and sclera. One of the treatment methods commonly used for hyperbilirubinemia is phototherapy in which newborns are exposed to visible light, especially within the green-blue spectrum. This study aimed to design a prototype of a portable phototherapy unit for newborns with hyperbilirubinemia. The phototherapy unit was designed by using a Surface Mounting Device Light Emitting Diode (SMD LED) with a wavelength of 400-520 nm as a light source which was attached to a fabric inside a box made of acrylic. The SMD LED strips were arranged with a spacing of 5 cm between the SMD LED arrays. The system was equipped with a monitoring system using SHT11 as a temperature and humidity sensor as well as a timer to adjust the duration of exposure and the LCD. The prototype was tested by irradiating various concentrations of artificial bilirubin solutions with a blue light produced by the phototherapy unit. The results show that the system can reduce the concentration of artificial bilirubin solution with an average reduction of 30.8%. The system shows the potential to be used as a portable phototherapy unit, further improvement on the efficacy, safety and comfort of the unit is required.

High‐Efficiency Deep‐Blue Solution‐Processed Organic Light‐Emitting Diodes Using Carbazole Dendrons Modified Hybridized Local and Charge‐Transfer Emitters

AbstractIn the pursuit of efficient and cost‐effective organic light‐emitting diodes (OLEDs), the development of solution‐processed hybridized local and charge transfer (HLCT) emitters presents a promising approach. HLCT materials uniquely integrate the advantages of both singlet and triplet excitons, surpassing the traditional spin statistical limit of 25 % while offering high photoluminescence efficiency and balanced charge transport properties. Herein, we report the synthesis and characterization of two new deep blue, solution‐processable HLCT fluorophores, G1FTPI and G2FTPI. These compounds incorporate fluorenyl carbazole dendron units into the HLCT luminogenic triphenylamine‐phenanthroimidazole (TPI) molecule. Their HLCT and photoluminescence (PL) properties were experimentally and theoretically investigated using solvation effects and density functional theory (DFT) calculations. The molecules exhibit deep blue emission with a high solid‐state fluorescence quantum yield, good solution‐processed film‐forming quality, and high hole mobility values of 2.18–2.61×10−6 cm2 V−1 s−1. Both compounds were successfully employed as non‐doped emissive layers in solution‐processed OLEDs, demonstrating excellent electroluminescent (EL) performance. Notably, the G2FTPI‐based device emitted a deep blue light at 432 nm with CIE coordinates of (0.158, 0.098) and achieved a maximum current efficiency (CEmax) of 3.13 cd A−1 and a maximum external quantum efficiency (EQEmax) of 5.30 %.

Assessing light spectrum impact on growth and antioxidant properties of basil family microgreens

Understanding the influence of light spectra on plant growth and antioxidant activities is crucial for optimizing cultivation practices and enhancing crop quality. In this study, we investigated the effects of different light treatments on growth parameters and antioxidant activities in five plant species: peppermint, Thai basil, cumin, lemon basil, and green holy basil. Our results revealed distinct responses to varying light spectra, with green light consistently promoting taller plant heights across all species. Additionally, blue light induced notable increases in plant width for certain species. Analysis of antioxidant activities demonstrated dynamic fluctuations in Total Phenolic Content (TPC) and Flavonoid Content (TFC) among different light treatments and plant species. While white and red light generally promoted higher TPC levels, blue light unexpectedly exhibited the highest TPC levels at specific time points. Moreover, investigation into DPPH Radical Scavenging activity revealed diverse temporal responses to light spectra, with blue light demonstrating exceptional activity at early stages and white and red light showing heightened activity at later time points. These findings underscore the importance of tailored light regimes in optimizing growth parameters and enhancing antioxidant activities in cultivated plants, thereby offering promising avenues for sustainable agriculture and food production practices.

Manipulating flavonoid biosynthesis in Trigonella persica through controlled spectral lighting

Trigonella persica Boiss., is renowned for its rich phytochemical profile, particularly the presence of the flavonol quercetin. This study explored the effects of various light treatments, including blue, red, blue-red (1:1) radiation (BRR), and pink fluorescent light (PFL), on the biochemical and molecular mechanisms governing quercetin and flavonoid biosynthesis in T. persica at different growth stages. Our results showed that light treatments significantly influenced the activity of key enzymes phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) during germination and vegetative growth, with blue light inducing higher PAL and TAL activities compared to control conditions. High-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyses revealed that 48-h-old sprouts grown under red light exhibited the highest levels of flavonoid components and phenolic acids, with catechin as the predominant flavonoid. Notably, BRR treatment led to elevated concentrations of the bioavailable quercetin-3-rhamnoside in 48-h-old sprouts, while 15-day-old plants grown under PFL conditions showed a significant accumulation of the sulfated quercetin-3-sulfate. Real-time PCR analysis demonstrated that BRR upregulated the expression of flavonoid biosynthesis genes PAL, chalcone synthase (CHS), and chalcone isomerase (CHI) in sprouts, whereas PFL treatment induced higher expression of these genes, as well as cinnamate 4-hydroxylase (C4H), in aerial parts. These findings suggest that targeted light treatments, particularly blue and red LED light, can enhance the accumulation of bioavailable quercetin-3-rhamnoside during T. persica germination and sprouts exhibit higher levels of flavonoids and phenolic acids than aerial parts during different vegetative growth stages.

Supplemental Low-Irradiance Mono/Polychromatic LED Lighting Significantly Enhances Floral Biology of the Long-Day F1 Hybrid Strawberry ‘Soraya’ (Fragaria x ananassa Duch.)

Floral and vegetative responses of the strawberry (Fragaria x ananassa Duch.) to specific light wavelengths are not well documented. LED lights make it feasible for precise exposure to specific wavelengths during a 24 h cycle to alter growth responses regulated by phytochromes and cryptochromes and thereby potentially enhance fruit productivity in both a controlled environment and field systems or to enhance stolon production for controlled environment propagation. This research developed a systematic method to assess the effects of supplemental, low-irradiance LED lighting on strawberry flowering and vegetative biology. Growth of the long-day F1 seed-propagated cultivar ‘Soraya’ was evaluated during and following 6 or 12 weeks of exposure to supplemental red (660 nm), far-red (730 nm), blue (454 nm), or incandescent lighting at various times during the dark period of a 24 h cycle under a 10 h non-inductive photoperiod at non-inductive temperatures (>27/18 °C, day/night). Treatment effects were monitored via flower mapping and phenology during treatment, field and greenhouse production after treatment, and floral scores derived by ranking treatment effects within the evaluation method and then combining them into a single, simple score. The most promising treatment for enhancing the floral nature of plug plants was exposure to far-red + red light as a 5 h night interruption. This treatment increased inflorescence production in the greenhouse by 285% and resulted in multi-branched, floral plants with the potential for enhancing yield in either greenhouse or field production. Greenhouse runner production increased by 483% following exposure to incandescent lighting at the beginning of the dark period; thus, this treatment or one using a spectral distribution similar to incandescent may be suitable for enhancing vegetative propagation in controlled environments.

Design and Synthesis of Aggregation‐Caused Quenching Hydroxy‐Phenanthroimidazole Derivatives for Probing of Fe3+ Ions and as Potential Blue Light Emitters

AbstractFluorescence aggregated molecules tend to employ versatile opportunities in metal ion probe sensors and fluorescent lighting. To achieve this dual challenging task, currently synthesized three phenanthroimidazole‐naphthalene‐based compounds Pq‐tBu‐OH, Pq‐mF‐OH, and Pq‐pF‐OH are derived based on substitution at N1 position for better photophysical and electrochemical properties. Compared experimental and theoretical calculations define the highest bandgap to be 2.75 eV of Pq‐pF‐OH, and the same molecule expressed a higher (348 °C) thermal decomposition. The calculated singlet and triplet energies found in the range of 3.24–3.67 and 2.70–2.72 eV indicate well energy transfer from S1→S0 (quantum yield of 23.36 %, lifetime is 4.05 ns). Among the numerous morphologies, the solid form exhibited improved intensive deep blue emission (x=0.159, y=0.051), and its InGaN LED results demonstrated a strong deep blue emission at 418 nm. Moreover, the fluorophores were experimentally visualizing the aggregation‐caused quenching (ACQ) which enables the probing of Fe3+ ion. However, for the first time, the ACQ‐assisted concept is applied through synthesized molecules for Fe3+ ion probing via fluorescence spectra, Job's plot calculation, and 1H NMR results. In addition, the probe works excellently at a detection limit of 10 μM and it could also act as a potential competitor for lighting applications.

Immediate effect of sunlight exposure through blue glass on blood pressure in hypertensive patients: a randomized controlled trial.

Hypertension affects approximately 1.28 billion adults worldwide, driving the search for integrative therapeutic approaches alongside conventional treatments. While chromotherapy, particularly blue light exposure, has historical roots in traditional medicine and its specific impact on blood pressure regulation remains understudied. So, the present study aims to investigate the immediate impact of exposure to blue glass through sunlight on blood pressure in hypertensive individuals. This randomized controlled trial was carried out with a sample of 60 hypertensive patients, who were divided into two groups: a study group that received blue glass exposure for 20 min and a control group that received exposure to colourless glass. The primary outcome measures were systolic and diastolic blood pressure, pulse rate, and oxygen saturation levels. The results of the study revealed statistically significant differences in systolic blood pressure (p=0.006) and pulse rate (p=0.005) after the intervention in the study group and no such changes were noted in the control group. The findings of this study suggest that blue glass exposure has a significant impact on reducing blood pressure and pulse rate in hypertensive patients, indicating its potential use as a integrative treatment in the management of hypertension.

An antimicrobial blue light prototype device controls infected wounds in a preclinical porcine model.

We developed a translational prototype antimicrobial blue light (ABL) device for treating skin wounds with ABL. Partial-thickness surgical wounds were created in live swine, an animal whose skin is considered the most like human skin, then heavily contaminated and left untreated for 24 hours with methicillin-resistant Staphylococcus aureus (MRSA). ABL treatment stabilized and reduced MRSA infection by greater than four orders of magnitude (>99.99%; p<0.0001) compared with untreated wounds in the same animal, after only two daily treatments. These data support further development of such devices for controlling infection in skin wounds. ABL, with or without concomitant administration of negative pressure, antimicrobials, or photosensitizers, could play an important role in modern wound care by reducing the amount, duration, and cost of antibiotics needed, helping reduce AMR. No such device for treating human cutaneous wounds currently exists. This deserves further development and study.

Effect of Combination of Blue and Red Light with Terbinafine on Cell Viability and Reactive Oxygen Species in Human Keratinocytes: Potential Implications for Cutaneous Mycosis.

Cutaneous mycoses are common infections whose treatment has become more complex due to increasing antifungal resistance and the need for prolonged therapies, hindering patient adherence and increasing the incidence of adverse effects. Consequently, the use of physical therapies, especially photodynamic therapy (PDT), has increased for the treatment of onychomycosis due to its antimicrobial capacity being mediated by the production of reactive oxygen species. This study investigates the in vitro effect of applying blue light (448 nm) or red light (645 nm), alone or together with terbinafine, on the viability of human keratinocytes and the production of reactive oxygen species. The combination of terbinafine and blue light significantly increases ROS production and caspase-3 expression, while red light together with terbinafine increases catalase, superoxide dismutase (SOD) and PPARγ expression, which reduces the amount of ROS in the cultures. The effect of both treatments could be useful in clinical practice to improve the response of cutaneous mycoses to pharmacological treatment, reduce their toxicity and shorten their duration.

Optogenetic activation of serotonergic neurons changes masticatory movement in freely moving mice

The serotonergic system modulates the neural circuits involved in jaw movement; however, the role of serotonin (5-HT) neurons in masticatory movement remains unclear. Here, we investigated the effect of selective activation of 5-HT neurons in the dorsal raphe nucleus (DRN), or the raphe obscurus nucleus (ROb), on voluntary masticatory movement using transgenic mice expressing the channelrhodopsin-2 (ChR2) mutant (C128S) in central 5-HT neurons. During voluntary mastication, DRN blue light illumination increased masticatory frequency and decreased the root mean square peak amplitude of electromyography (EMG) in the masseter muscles. DRN blue light illumination also decreased EMG burst duration in the masseter and digastric muscles. These changes were blocked by a 5-HT2A receptor antagonist. Conversely, ROb blue light illumination during voluntary mastication did not affect masticatory frequency and EMG bursts in the masseter and digastric muscles. DRN or ROb blue light illumination during the resting state did not induce rhythmic jaw movement such as mastication but induced an increase in EMG activity in masseter and digastric muscles. These results suggest that both DRN and ROb 5-HT neurons may facilitate jaw movement. Furthermore, DRN 5-HT neuron may contribute to changes in masticatory patterns during the masticatory sequence.

The effect of different light spectra on selenium bioaccumulation by Spirulina platensis cyanobacteria in flat plate photobioreactors

Selenium (Se) plays a crucial role in human health, influencing conditions such as cancer, diabetes, and neurological disorders. With global population growth and unequal nutrient distribution threatening food security, new approaches are needed to meet the nutritional needs of the world. Se is essential for immune function, metabolism, and antioxidant defense, and in regions suffering from food insecurity and malnutrition, selenium-enriched food could offer an affordable solution. Spirulina platensis, microalgae, can bioaccumulate Se from its environment, enhancing its nutritional value. This study explores how different light spectra (red, white, yellow, and blue LEDs) affect Se bioaccumulation in Spirulina when Na2SeO3 is added to the culture medium in photobioreactors. The results show that red light made the highest Se bioaccumulation (0.118 mg.L−1), followed by white, yellow, and blue light. Se addition also increased cell dry weight by 46%, 33%, 22%, and 60%, respectively, compared to photobioreactors without Se, with biomass productivity highest under red light. Furthermore, Se boosted maximum Chl α concentration, improving photosynthetic efficiency. These findings suggest that optimizing light conditions can significantly enhance the nutritional value of Spirulina, offering a potential solution to global hunger by providing a sustainable, selenium-enriched food source.

TMOD-22. MULTIREGION BIOPSIES AND CORRESPONDING NEUROSPHERE CULTURES REVEAL SPATIAL DIVERGENCE IN GLIOBLASTOMA EVOLUTION

Abstract Spatial organization of normal tissues is key for their function, yet the role of distribution of distinct clones of cancer cells in tumor is not usually studied as a potential vulnerability in cancer. This is of particular interest in glioblastoma (GBM), in which extensive intratumor heterogeneity hampers effectiveness of treatment. To better understand tumor evolution and the complexity of cancer ecosystem in GBM, we performed profiling of biopsies collected from MRI-defined regions of the tumors, spanning the surface, tumor core and deep tumor margins, which drive local recurrence after surgery. To test how spatially distinct biopsies differ in their cancer cell composition and to assess the tumor microenvironment heterogeneity, we took advantage of 5-ALA metabolite fluorescence, which accumulates in GBM cells and allows the surgeon to visualize cancer under blue light. We used it to separate cancer cells (predominantly 5-ALAhigh) from tumor microenvironment (5-ALAlow) and subjected the fractions to bulk and single cell transcriptomics, respectively. We found a gradient of cellular states associated with location in the tumor, with the deep margin samples having more 5-ALAlow cancer cells and generally less defined phenotype. We have also developed neurosphere cultures from our collection of spatially distant biopsies. Despite the selection pressure of the in vitro culture conditions, cells from different regions of the tumor adopted different morphologies, suggesting retention of some of their differential features. The differences between cultures were reflected in metabolism, proliferation, and differential sensitivity to a drug panel. Whole exome sequencing and transcriptomic analysis were also performed to identify the selection bottleneck of culture conditions, establish evolutionary trajectory of the distinct regions and neurosphere cultures, and test how strongly our cultures represent both the 5-ALAhigh and 5-ALAlow subpopulations of GBM cells. Our study identified properties associated with different spatial locations within GBM tumors, which will help uncover the cellular and microenvironmental dependencies that could lead to novel therapeutic targets for this highly heterogeneous tumor.