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Green Preparation of Fluorescent Carbon Quantum Dots from Cyanobacteria for Biological Imaging
摘要： Biomass-based carbon quantum dots (CQDs) have become a significant carbon materials by their virtues of being cost-effective, easy to fabricate and low in environmental impact. However, there are few reports regarding using cyanobacteria as a carbon source for the synthesis of fluorescent CQDs. In this study, the low-cost biomass of cyanobacteria was used as the sole carbon source to synthesize water-soluble CQDs by a simple hydrothermal method. The synthesized CQDs were mono-dispersed with an average diameter of 2.48 nm and exhibited excitation-dependent emission performance with a quantum yield of 9.24%. Furthermore, the cyanobacteria-derived CQDs had almost no photobleaching under long-time UV irradiation, and exhibited high photostability in the solutions with a wide range of pH and salinity. Since no chemical reagent was involved in the synthesis of CQDs, the as-prepared CQDs were confirmed to have low cytotoxicity for PC12 cells even at a high concentration. Additionally, the CQDs could be efficiently taken up by cells to illuminate the whole cell and create a clear distinction between cytoplasm and nucleus. The combined advantages of green synthesis, cost-effectiveness and low cytotoxicity make synthesized CQDs a significant carbon source and broaden the application of cyanobacteria and provide an economical route to fabricate CQDs on a large scale.
关键词： bioimaging,cyanobacteria,carbon quantum dots,hydrothermal method
更新于2025-11-21 11:08:12
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Spectral discrimination of planktonic cyanobacteria and microalgae based on deep UV fluorescence
摘要： The deep ultraviolet fluorescence characteristics of several cyanobacteria and microalgae are analyzed and exploited for their discrimination in liquid samples. The proposed approach is based on relative fluorescence peak amplitude of natural pigments in cyanobacteria or other planktonic species commonly present in water bodies. The experimental results demonstrate a clear discrimination between the various species of cyanobacteria and other planktonic species. This approach can be simply implemented in fluorescence measurement systems for real-time detection of cyanobacteria, provided that they are able to operate in deep ultraviolet.
关键词： Autofluorescence,Portable sensor,Cyanobacteria,Fluorescence spectroscopy
更新于2025-09-23 15:23:52
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Role of light emitting diode (LED) wavelengths on increase of protein productivity and free amino acid profile of Spirulina sp. cultures
摘要： LEDs have specific wavelengths that can positively influence the production of microalga biomass and biomolecules of interest. Filling the gaps in the literature, this study evaluated the effect of different LED wavelengths and photoperiods on protein productivities and free amino acid (FAA) profile of Spirulina sp. LEB 18 cultures. The best protein productivity results were obtained in red and green LED cultures using integral and partial photoperiods, respectively. In these experiments, protein productivities increased 2 and 1.6 times, respectively, compared to the control culture using fluorescent light. Green LEDs in partial photoperiod provided also the highest concentrations of essential and non-essential FAA, about 1.8 and 2.3 times higher, respectively, than control cultures. LEDs showed to be a promising sustainable light source for increasing protein productivity and FAA concentration in Spirulina sp. LEB 18 cultures.
关键词： Photoperiod,Microalgae,Protein productivity,Cyanobacteria,Light source
更新于2025-09-23 15:21:01
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An Environmentally Friendly Method for Testing Photocatalytic Inactivation of Cyanobacterial Propagation on a Hybrid Ag-TiO2 Photocatalyst under Solar Illumination
摘要： Cyanobacteria were inactivated under sunlight using mixed phase silver (Ag) and deposited titanium dioxide (TiO2) coated on the surface of diatomite (DM) as a hybrid photocatalyst (Ag-TiO2/DM). The endpoints of dose-response experiments were chlorophyll a, photosynthetic efficiency, and flow cytometry measurements. In vitro experiments revealed that axenic cultures of planktonic cyanobacteria lost their photosynthetic activity following photocatalyzed exposure to sunlight for more than 24 h. Nearly 92% of Microcystis aeruginosa cells lost their photosynthetic activity, and their cell morphology was severely damaged within 24 h of the reaction. Preliminary carbon-14 (14CO3^2-) results suggest that the complete inactivation of cyanobacteria arises from damage to cell wall components (peroxidation). A small concomitant increase in cell wall disorder and a consequent decrease in cell wall functional groups increase the cell wall fluidity prior to cell lysis. A high dosage of Ag-TiO2/DM during photocatalysis increased the concentration of extracellular polymeric substances (EPSs) in the Microcystis aeruginosa suspension by up to approximately 260%. However, photocatalytic treatment had a small effect on the disinfection by-product (DBP) precursor, as revealed by only a slight increase in the formation of trihalomethanes (THMs) and haloacetic acids (HAAs).
关键词： titanium dioxide,silver,extracellular polymeric substances,photocatalysis,disinfection by-products,cyanobacteria
更新于2025-09-19 17:15:36
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Fluorescence as a Surrogate for the Release of Intracellular Material From Cyanobacteria
摘要： Water treatment plants that apply preoxidation before physical cell removal can compromise cyanobacterial cell integrity and cause the release of intracellular organic matter (IOM) containing toxic or odorous metabolites. In this study, fluorescence was evaluated as a surrogate for IOM released from cyanobacterial cells following oxidation with ozone, chlorine, chlorine dioxide, or monochloramine. Oxidation of 200,000 cells/mL of Microcystis aeruginosa led to a significant increase in both the fluorescence index (FI) and the fluorescent dissolved organic matter (FDOM) intensity (excitation wavelength, 370 nm; emission wavelength, 460 nm). FI and FDOM proved impractical for detecting weakly fluorescing IOM released from Oscillatoria sp. and Lyngbya sp., indicating that the viability of fluorescence monitoring is cyanobacteria-specific. For strongly fluorescing IOM, FI and FDOM can serve as qualitative surrogates for the concomitant release of metabolites. Elevated FI and FDOM were not sensitive to the concentration of microcystin-LR but can provide an early warning that a utility’s source water is at risk for metabolite release and accumulation.
关键词： fluorescence index,cyanobacteria,Microcystis aeruginosa,fluorescent dissolved organic matter,intracellular organic matter,microcystin-LR
更新于2025-09-19 17:15:36
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White and red LEDs as two-phase batch for cyanobacterial pigments production
摘要： Carotenoids and phycobiliproteins have a high economic value, due to their wide range of biological and industrial applications. The implementation of strategies to increase their production, such as the application of two-phase light cultivation systems, can stimulate pigments production, increasing economic turnover. In this sense, Cyanobium sp. was grown in seven different two-phase white/red cultivation arrangements, varying the time of each light from 0 to 21 days. Biomass, photosynthetic activity, pigments profile and antioxidant capacity were measured along time. Red light increased photosynthetic activity and pigments content (ca. 1.8-fold), and the use of a two-phase cultivation system generally raised bioactivity and production of phytochemicals. Among the studied, the optimal cultivation condition was found with 10 days of white followed by 4 days of red light. The optimized growth led to a productivity of 137.4 ± 0.8 mg.L-1.d-1 of biomass, 17.0 ± 0.2 mg.L-1.d-1 of total phycobiliproteins and 4.5 ± 0.2 mg.L-1.d-1 of carotenoids
关键词： cyanobacteria,carotenoids,phycobiliproteins,antioxidant capacity,light-emitting diode
更新于2025-09-16 10:30:52
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Development of a longevous two-species biophotovoltaics with constrained electron flow
摘要： Microbial biophotovoltaics (BPV) offers a biological solution for renewable energy production by using photosynthetic microorganisms as light absorbers. Although abiotic engineering approaches, e.g., electrode modification and device optimization, can enhance the electrochemical communication between living cells and electrodes, the power densities of BPV are still low due to the weak exoelectrogenic activity of photosynthetic microorganisms. Here, we develop a BPV based on a D-lactate mediated microbial consortium consisting of photosynthetic cyanobacteria and exoelectrogenic Shewanella. By directing solar energy from photons to D-lactate, then to electricity, this BPV generates a power density of over 150 mW·m?2 in a temporal separation setup. Furthermore, a spatial-temporal separation setup with medium replenishment enables stable operation for over 40 days with an average power density of 135 mW·m?2. These results demonstrate the electron flow constrained microbial consortium can facilitate electron export from photosynthetic cells and achieve an efficient and durable power output.
关键词： biophotovoltaics,electron flow,microbial consortium,cyanobacteria,renewable energy,D-lactate,Shewanella
更新于2025-09-12 10:27:22
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - 3D Bioprinting of Cyanobacteria for Solar-driven Bioelectricity Generation in Resource-limited Environments
摘要： We demonstrate a hybrid biological photovoltaic device by forming a 3D cooperative biofilm of cyanobacteria and heterotrophic bacteria. 3D bioprinting technique was applied to engineer a cyanobacterial encapsulation in hydrogels over the heterotrophic bacteria. The device continuously generated bioelectricity from the heterotrophic bacterial respiration with the organic biomass supplied by the cyanobacterial photosynthesis. This innovative device platform can be the most suitable power source for unattended sensors, especially for those deployed in remote and resource-limited field locations.
关键词： 3D bioprinting,heterotrophic bacteria,unattended sensors,hybrid biological photovoltaic device,3D cooperative biofilm,cyanobacteria,bioelectricity
更新于2025-09-11 14:15:04
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Interpretation of total phytoplankton and cyanobacteria fluorescence from cross-calibrated fluorometers, including sensitivity to turbidity and colored dissolved organic matter
摘要： In vivo pigment ?uorescence methods allow simple real-time detection and quanti?cation of freshwater algae and cyanobacteria. Available models are still limited to high-cost ?uorometers, validated for single instruments or individual water bodies, preventing data comparison between multiple instruments, and thus, restricting their use in large-scale monitoring programs. Moreover, few models include corrections for optical interference (water turbidity and colored dissolved organic matter, CDOM). In this study, we developed simple models to predict phytoplankton and cyanobacterial chlorophyll a (Chl a) concentrations based on Chl a and C-phycocyanin in vivo ?uorescence, using multiple low-cost handheld ?uorometers. We aimed to: (1) ?t models to mixed cyanobacterial and microalgal cultures; (2) cross-calibrate nine ?uorometers of the same brand and series; (3) correct the CDOM and turbidity effects; and (4) test the algorithms’ performance with natural samples. We achieved comparable results between nine instruments after the cross-calibration, allowing their simultaneous use. We obtained algorithms for total and cyanobacterial Chl a estimation. We developed parametric corrections to remove CDOM and turbidity interferences in the algorithms. Five sampling sites (from a lake, a stream, and an estuary) were used to test the algorithms using eight cross-calibrated ?uorometers. The models showed their best performance after CDOM and turbidity corrections (total Chl a: R2 = 0.99, RMSE = 7.8 μg Chl a L?1; cyanobacterial Chl a: R2 = 0.98, RMSE = 9.8 μg Chl a L?1). In summary, our models can quantify total phytoplankton and cyanobacterial Chl a in real time with multiple low-cost ?uorometers, allowing its implementation in large-scale monitoring programs.
关键词： CDOM,monitoring,turbidity,fluorescence,cyanobacteria,fluorometers,chlorophyll a,phytoplankton
更新于2025-09-10 09:29:36
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Synthesizing, characterizing, and toxicity evaluating of Phycocyanin-ZnO nanorod composites: A back to nature approaches
摘要： C-Phycocyanin pigment was purified from a native cyanobacterial strain using a novel consecutive multi-step procedure and utilized for the first time for the green synthesis of phycocyanin-zinc oxide nanorods (PHY-ZnO NRs) by a simple, low-cost and eco-friendly approach. The PHY-ZnO NRs were characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), zeta potential measurement, FTIR, SEM, TEM, differential scanning calorimetry (DSC), thermogravimetric (TGA), and EDX spectroscopy analysis. The UV-Vis spectra showed an absorption band at 364 nm which is characteristic of ZnO nanoparticles (ZnONPs). The rod-shaped PHY-ZnO NRs observed in the TEM and SEM images had an average diameter size of 33 nm, which was in good agreement with the size calculated by XRD. The elemental analysis of PHY-ZnO NRs composition showed that three emission peaks of zinc metal and one emission peak of oxygen comprised 33.88% and 42.50%, respectively. The thermogram of PHY-ZnO NRs sample exhibited the weight loss of biosynthesized nanoparticles registered to be 3 %, emphasizing the purity and heat stability of zinc oxide nanorods coated with phycocyanin pigment-protein. MTT assay indicated that PHY-ZnO NRs had a less cytotoxicity on fibroblast L929 compared to the ZnONRs-treated cells. A remarkable increase in ROS level was measured in cells treated with ZnO at final concentrations of 100, 200 and 500 μg/ml (78±7, 99±8 and 116±11, respectively). When it comes to PHY-ZnO NRs, a protective effect for phycocyanin was detected which declined the level of ROS content as confirmed by fluorescent microscopy. The distinctive features of phycocyanin for surface functionalization of ZnO nanoparticles deserve to be deemed as a nano-drug candidate for further researches.
关键词： Cyanobacteria,Green synthesis,MTT assay,Phycocyanin,Zinc oxide nanoparticles
更新于2025-09-10 09:29:36