Antioxidant, AChE inhibitory, and anticancer effects of Verbascum thapsus extract.

Verbascum thapsus (VT) is a medicinal plant that is used in folk medicine to treat a variety of ailments. For this study, the biological functions of VT methanol extract were determined in vitro. The plant's methanol extract was created through the maceration process. The phytochemical composition of plant extracts was investigated using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The antioxidant capacity of the extract was determined using the DPPH (2,2-diphenyl-1-picrylhydrazil) and ABTS (2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) tests and its cytotoxicity was assessed using the MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole)) assay on the Caco-2 (human colorectal adenocarcinoma cells), LNCaP (Lymph Node Carcinoma of the Prostate), and HEK293 cell lines (Human embryonic kidney 293 cells) used to model colon, prostate, and non-cancerous cells. VT extract showed low DPPH and ABTS radical scavenging activities compared to standard antioxidants at 30 mg/ml concentration. In addition, it was determined that VT extract inhibited acetylcholinesterase enzyme.

Synergistic Nanowire-Enhanced Electroporation and Electrochlorination for Highly Efficient Water Disinfection.

Conventional water disinfection methods such as chlorination typically involve the generation of harmful disinfection byproducts and intensive chemical consumption. Emerging electroporation disinfection techniques using nanowire-enhanced local electric fields inactivate microbes by damaging their outer structures without byproduct formation or chemical dosing. However, this physical-based method suffers from a limited inactivation efficiency under high water flux due to an insufficient contact time. Herein, we integrate electrochlorination with nanowire-enhanced electroporation to achieve a synergistic flow-through process for efficient water disinfection targeting bacteria and viruses. Electroporation at the cathode induces sub-lethal damages on the microbial outer structures. Subsequently, electrogenerated active chlorine at the anode aggravates these electroporation-induced injuries to the level of lethal damage. This sequential flow-through disinfection system achieves complete disinfection (>6.0-log) under a very high water flux of 2.4 × 104 L/(m2 h) with an applied voltage of 2.0 V. This disinfection efficiency is 8 times faster than that of electroporation alone. Further, the specific energy consumption for the disinfection by this novel process is extremely low (8 × 10-4 kW h/m3). Our results demonstrate a promising method for rapid and energy-efficient water disinfection by coupling electroporation with electrochlorination to meet vital needs for pathogen elimination.

Self-powered portable melt electrospinning for in situ wound dressing.

BACKGROUND: Electrospun (e-spun) nanofibers for wound dressing have attracted wide attention due to its large specific surface area, large porosity and breathability. Compared with solution electrospinning (e-spinning), melt e-spinning is more bio-friendly without toxic solvent participation, which provides the possibility of in situ e-spinning on wounds directly. However, previously reported melt e-spinning devices were usually bulky and cumbersome due to their necessary heating unit, and different components were separated to avoid electrostatic interference. RESULTS: In this article, we report on a self-powered hand-held melt e-spinning gun which can work without any external power supply (outdoors). The problem of electrostatic interference for this integrated device was solved by using a special high heat transfer insulation unit. The apparatus is easy and safe to operate by a single hand due to its small volume (24 × 6 × 13 cm3) and light weight (about 450 g). Some biodegradable polymers, for example, polycaprolactone (PCL) fibers were successful e-spun onto wounds directly by using this dressing gun. CONCLUSIONS: PCL fibrous membrane has good biocompatibility and can be in situ electrospun to wound surface as a wound dressing by the portable melt e-spinning gun. Besides wound dressing, this hand-held melt e-spinning gun may be used in 3D printing and experimental teaching demonstration aids.

Meta-analysis of the association of IL2RA polymorphisms rs2104286 and rs12722489 with multiple sclerosis risk.

BACKGROUND: The interleukin-2 receptor alpha (IL2RA) gene polymorphisms may be implicated in the genetic susceptibility to multiple sclerosis (MS). This meta-analysis aims to evaluate the relationship of the IL2RA polymorphisms rs2104286 and rs12722489 with MS risk in different populations. METHODS: Eligible association studies were identified through search in Pubmed, Medline, Web of Science, and Scopus (end of search: August 2017). Summary odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random-effects or fixed-effects models. All statistical analyses were two-sided. RESULTS: Eleven studies including 8608 cases and 9061 controls evaluated rs2104286. The results demonstrated that the A allele of rs2104286 was associated with increased risk of MS in Caucasians (OR = 1.19, 95%CI: 1.13-1.25, p < 0.001) and Asians (OR = 1.25, 95%CI: 1.01-1.55, p = 0.041), respectively. Concerning rs12722489, six studies with 4259 cases and 5420 controls were eligible. We found that the C allele of rs12722489 was associated with elevated MS risk in Caucasians (OR = 1.20, 95% CI: 1.12-1.29, p < 0.001) but not in Asians (OR = 1.10, 95%CI: 0.75-1.63, p = 0.629). Statistical evidence from the Egger and Begg tests showed absence of publication bias. Sensitivity analysis showed that the results were stable. CONCLUSION: Our meta-analysis suggests that the rs2104286 A allele is associated with increased MS risk in both Caucasians and Asians, whereas the rs12722489 C allele is associated with elevated MS risk in Caucasians but not in Asians.

Giant spontaneous exchange bias obtained by tuning magnetic compensation in samarium ferrite single crystals.

Spontaneous exchange bias (SEB) under zero field cooling (ZFC) has recently attracted lots of attention due to its underlying physics and potential applications. Here we report the giant SEB (GSEB) of SmFeO3 single crystals by tuning magnetic compensation by temperature, which is rather convenient. A SEB field of up to 1 T at 3.9 K after ZFC (-1.4 T at 3.9 K after field cooling) was obtained. The SEB shows reciprocal relationship with remnant magnetization.

Microalgae-based advanced municipal wastewater treatment for reuse in water bodies.

Reuse of secondary municipal effluent from wastewater treatment plants in water bodies could effectively alleviate freshwater resource shortage. However, excessive nutrients must be efficiently removed to prevent eutrophication. Compared with other means of advanced wastewater treatment, microalgae-based processes display overwhelming advantages including efficient and simultaneous N and P removal, no requirement of additional chemicals, O2 generation, CO2 mitigation, and potential value-added products from harvested biomass. One particular challenge of microalgae-based advanced municipal wastewater treatment compared to treatment of other types of wastewater is that concentrations of nutrients and N:P ratios in secondary municipal effluent are much lower and imbalanced. Therefore, there should be comprehensive considerations on nutrient removal from this specific type of effluent. Removal of nutrients and organic substances, and other environmental benefits of microalgae-based advanced municipal wastewater treatment systems were summarized. Among the existing studies on microalgal advanced nutrient removal, much information on major parameters is absent, rendering performances between studies not really comparable. Mechanisms of microalgae-based nitrogen and phosphorus removal were respectively analyzed to better understand advanced nutrient removal from municipal secondary effluent. Factors influencing microalgae-based nutrient removal were divided into intrinsic, environmental, and operational categories; several factors were identified in each category, and their influences on microalgal nutrient removal were discussed. A multiplicative kinetic model was integrated to estimate microalgal growth-related nutrient removal based majorly on environmental and intrinsic factors. Limitations and prospects of future full-scale microalgae-based advanced municipal wastewater treatment were also suggested. The manuscript could offer much valuable information for future studies on microalgae-based advanced wastewater treatment and water reuse.

[Quality Control and Biological Assessment of Automated Synthesized 3'-deoxy-3'-¹8F-fluorothymidine using CFN-MPS-200 Module].

OBJECTIVES: To synthesize 3'-deoxy-3'-¹8F-fluorotyhymidine)(¹8F-FLT) using CFN-MPS-200 automatic synthesis module, and evaluate its distribution in Wistar rats. METHODS: We used 3-N-Boc-5!d-O-dimethoxytrityl-3!d-O-nosyl-thymidine (Boc-FLT)-percursor as raw material to synthesize ¹8F-FLT without residual solvents. Its radiochemical purity was confirmed with radio-HPLC and thin layer chromatography (TLC). Normal Wistar rats were injected with 18 F-FLT and underwent PET scanning. RESULTS: The entire preparation procedure took about 60 min, which resulted in a radio chemical yield of (24±5)% (after attenuation correction, n =20) and radiochemical purity of over 99%, with 1.11×108 Bq/mL specific activity. The ¹8F-FLT solution was colorless and had a pH value between 7.0-8.0. ¹8F-FLT was mainly concentrated in the kidney, bladder, liver, bone marrow and Liver of normal Wistar rats. CONCLUSION: Automated synthesis of ¹8F-FLT using CFN-MPS-200 is a stable method, with high yield, safety without solvent, and acceptable quality.

Calotropin from Asclepias curasavica induces cell cycle arrest and apoptosis in cisplatin-resistant lung cancer cells.

Calotropin (M11), an active compound isolated from Asclepias curasavica L., was found to exert strong inhibitory and pro-apoptotic activity specifically against cisplatin-induced resistant non-small cell lung cancer (NSCLC) cells (A549/CDDP). Molecular mechanism study revealed that M11 induced cell cycle arrest at the G2/M phase through down-regulating cyclins, CDK1, CDK2 and up-regulating p53 and p21. Furthermore, M11 accelerated apoptosis through the mitochondrial apoptotic pathway which was accompanied by increase Bax/Bcl-2 ratio, decrease in mitochondrial membrane potential, increase in reactive oxygen species production, activations of caspases 3 and 9 as well as cleavage of poly ADP-ribose polymerase (PARP). The activation and phosphorylation of JNK was also found to be involved in M11-induced apoptosis, and SP610025 (specific JNK inhibitor) partially prevented apoptosis induced by M11. In contrast, all of the effects that M11 induce cell cycle arrest and apoptosis in A549/CDDP cells were not significant in A549 cells. Drugs with higher sensitivity against resistant tumor cells than the parent cells are rather rare. Results of this study supported the potential application of M11 on the non-small lung cancer (NSCLC) with cisplatin resistance.

Bioinformatics analysis of ferroptosis in spinal cord injury.

Ferroptosis plays a key role in aggravating the progression of spinal cord injury (SCI), but the specific mechanism remains unknown. In this study, we constructed a rat model of T10 SCI using a modified Allen method. We identified 48, 44, and 27 ferroptosis genes that were differentially expressed at 1, 3, and 7 days after SCI induction. Compared with the sham group and other SCI subgroups, the subgroup at 1 day after SCI showed increased expression of the ferroptosis marker acyl-CoA synthetase long-chain family member 4 and the oxidative stress marker malondialdehyde in the injured spinal cord while glutathione in the injured spinal cord was lower. These findings with our bioinformatics results suggested that 1 day after SCI was the important period of ferroptosis progression. Bioinformatics analysis identified the following top ten hub ferroptosis genes in the subgroup at 1 day after SCI: STAT3, JUN, TLR4, ATF3, HMOX1, MAPK1, MAPK9, PTGS2, VEGFA, and RELA. Real-time polymerase chain reaction on rat spinal cord tissue confirmed that STAT3, JUN, TLR4, ATF3, HMOX1, PTGS2, and RELA mRNA levels were up-regulated and VEGFA, MAPK1 and MAPK9 mRNA levels were down-regulated. Ten potential compounds were predicted using the DSigDB database as potential drugs or molecules targeting ferroptosis to repair SCI. We also constructed a ferroptosis-related mRNA-miRNA-lncRNA network in SCI that included 66 lncRNAs, 10 miRNAs, and 12 genes. Our results help further the understanding of the mechanism underlying ferroptosis in SCI.

Transdifferentiation of human adipose-derived stem cells into urothelial cells: potential for urinary tract tissue engineering.

Autologous urothelial cells (UCs) provide a cell source for urinary tissue engineering because they can be used safely due to their lack of immunogenicity. However, these cells cannot be harvested under the following circumstances: malignancy, infection and organ loss, etc. Human adipose-derived stem cells (HADSCs) possess the traits of high differentiation potential and ease of isolation, representing a promising resource for tissue engineering and regenerative medicine. Nevertheless, HADSCs have been poorly investigated in urology and the optimal approaches to induce HADSCs into urothelium are still under investigation. In this study, we hypothesized that the change of microenvironment by a conditioned medium was essential for the transdifferentiation of HADSCs into UCs. We then used a conditioned medium derived from urothelium to alternate the microenvironment of HADSCs. After 14 days of culture in a conditioned medium, about 25-50% HADSCs changed their morphology into polygonal epithelium-like shapes. In addition, these cells expressed up-regulating of urothelial lineage-specific markers (uroplakin 2and cytokeratin-18) and down-regulating of mesenchymal marker (vimentin) in RNA and protein level, respectively, which confirmed that HADSCs were induced into urothelial lineage cells. We also measured the growth factors in the conditioned medium in order to analyze the molecular mechanisms regulating transdifferentiation. We observed that the expression levels of PDGF-BB and VEGF were significantly higher than those of the control group after 14 days induction, suggesting they were abundantly secreted into the medium during the culturing period. In conclusion, HADSCs showed in vitro the upregulation of markers for differentiation towards urothelial cells by culturing in an urothelial-conditioned medium, which provides an alternative cell source for potential use in urinary tract tissue engineering.

Introduction to biodegradable polylactic acid ureteral stent application for treatment of ureteral war injury.

OBJECTIVE: • To study the operability and effectiveness of a biodegradable ureteral stent for clinical treatment of ureteral war injury using a canine model. MATERIALS AND METHODS: • A device was designed and employed to generate firearm fragment wounds in unilateral ureters (on randomly chosen sides) of nine beagles (Group A). The wounded ureters were then debrided and sutured. • Intravenous pyelography (IVP) and radioactive renography were performed 40, 80 and 120 days postoperatively. In Group B, firearm fragment wounds were made to the bilateral ureters in nine beagles. A polylactic acid stent was placed unilaterally (on a randomly chosen side) whereas the ureter on the other side was debrided and sutured without stenting. • Both IVP and radioactive renography were performed 40, 80 and 120 days postoperatively. The operability and effectiveness of the biodegradable ureteral stent were studied thereafter. RESULTS: • In Group A, hydronephrosis and hydroureter occurred and worsened postoperatively on the wounded sides in all nine beagles. The ratio of the renal partial concentration indices (RPCI) between the kidneys (unwounded side : wounded side) increased. • The ratio of the kidney washout half-time between the kidneys (unwounded side : wounded side) decreased. In Group B, neither hydronephrosis nor hydroureter was found postoperatively in the stented ureters but both occurred in the unstented ureters in all nine beagles. • The ratio of RPCI between kidneys (stented side : unstented side) increased whereas the kidney washout half-time ratio between the stented and unstented sides decreased. Differences were significant. CONCLUSION: • In Group A, the new canine model for firearm fragment wounds was tested and proved to be operable and effective. In Group B, hydronephrosis and hydroureter were effectively prevented in ureters by biodegradable stent placement compared with the non-stented ureters where hydronephrosis and hydroureter occurred. The renal concentration capacity was effectively protected and the half-time of kidney washout was shortened.

Recent progress and challenges in solution blow spinning.

In the past 30 years, researchers have worked towards reducing the size of ordinary three-dimensional (3D) materials into 1D or 2D materials in order to obtain new properties and applications of these low-dimensional systems. Among them, functional nanofibers with large surface area and high porosity have been widely studied and paid attention to. Because of the interesting properties of nanofibers, they find extensive application in filtration, wound dressings, composites, sensors, capacitors, nanogenerators, etc. Recently, a variety of nanofiber preparation methods such as melt blowing, electrospinning (e-spinning), centrifugal spinning and solution blow spinning (SBS) have been proposed. This paper includes a brief review of the fundamental principles of the preparation of nanofibers for solution jet spinning, the influence of experimental parameters, and the properties and potential applications of the solution-blown fibers. And the industrialization and challenges of SBS are also included.

Enhancement of Cr(VI) removal efficiency via adsorption/photocatalysis synergy using electrospun chitosan/g-C3N4/TiO2 nanofibers.

Chitosan/g-C3N4/TiO2 (CS/CNT) nanofibers were fabricated by electrospinning technique for Cr(VI) removal through the adsorption and photocatalytic processes. The effects of crucial factors in the adsorption process including contact time (0-1440 min), pH (1-7), initial concentration of Cr(VI) (20-800 mg/L) were investigated. The photocatalytic experiment was executed in a photochemical reactor with an 800 W xenon lamp to simulate visible light. In adsorption process, at pH = 2, the adsorption capacities of chitosan (CS) nanofibers, CS/CNT10:1 (CS : g-C3N4/TiO2 = 10:1) nanofibers and CS/CNT5:1 nanofibers were 20.8, 165.3 and 68.9 mg/g, respectively, suggesting the addition of g-C3N4/TiO2 (CNT) could notably enhance the acid resistance of CS and widen its practical application. Under visible-light irradiation, the removal efficiency of Cr(VI) using CS/CNT nanofibers was appreciably improved, which was about 50 % higher than that of pure adsorption, indicating that the CS/CNT nanofibers exhibited the effective synergistic effect of adsorption and photocatalysis.

A novel diagnostic method for distinguishing between Fe(IV) and •OH by using atrazine as a probe: Clarifying the nature of reactive intermediates formed by nitrilotriacetic acid assisted Fenton-like reaction.

In this work, we found that the distribution of two specific atrazine (ATZ) oxidation products (desethyl-atrazine (DEA) and desisopropyl-atrazine (DIA)) was different in oxidation processes involving aqueous ferryl ion (Fe(IV)) species and •OH. Specifically, the molar ratio of produced DEA to DIA (i.e., [DEA]/[DIA]) increased from 7.5 to 13 with increasing pH from 3 to 6 when ATZ was oxidized by Fe(IV), while the treatment of ATZ by •OH led to the [DEA]/[DIA] value of 2 which was independent of pH. Moreover, ATZ showed high reactivity towards Fe(IV) over a wide pH range, especially at near-neutral pH, at which ATZ oxidation in Fe(II)/peroxydisulfate system was even much faster than another well-defined Fe(IV) scavenger, the sulfoxides. By using this approach, it was obtained that the [DEA]/[DIA] value remained at 2 during ATZ transformation by the nitrilotriacetic acid (NTA) assisted Fenton-like (Fe(III)/H2O2) system, which was independent of solution pH and reactants dosage. This result clarified that •OH was the primary reactive intermediate formed in the NTA assisted Fe(III)/H2O2 system. This study not only developed a novel sensitive diagnostic tool for distinguishing Fe(IV) from •OH, but also provided more credible evidence to the nature of reactive intermediate in a commonly controversial system.

High output achieved by sliding electrification of an electrospun nano-grating.

The rapid development of flexible and wearable electronics has proposed a trend towards miniaturization, mobility, versatility and artificial intelligence. Triboelectric nanogenerators (TENGs) can make use of micro/nano multi-functional materials to harvest and store energy from the surrounding environment efficiently, which can drive smart portable electronics operating continuously and steadily. The increase in the output power density of the triboelectric nanogenerator requires new designs. In this work, a new grating TENG was proposed, and the two friction layers were fabricated by near-field electrospinning and conventional electrospinning with two parallel electrodes as a collector, respectively. The basic model of the simulation was simplified according to the highly ordered structure and the repeatability of the TENG grating structure. The effect of the effective contact area on the output of the TENG was further proved by fitting the calculation regularity of the two models with the experimental results. At the same time, the effect of the redundant electrode on the output of the TENG was verified by experiments. We found that this nanogenerator can achieve a very high output of 1800 W m-2 due to a more refined grating structure combined with modification of the contact area. The TENG can also be used as a selfpowered sensor to detect mechanical signals, which requires no additional power source to drive it. Meanwhile, the anisotropic nature of the TENG can also be utilized to sense angles, lock devices or encrypt information. This output control technology provides a more effective idea for future output power improvement, that is, a new generation of high-output TENGs can be designed by effectively adjusting the corresponding contact area and electrode area.

Enhanced simultaneous removal of nitrogen, phosphorous, hardness, and methylisothiazolinone from reverse osmosis concentrate by suspended-solid phase cultivation of Scenedesmus sp. LX1.

The disposal of reverse osmosis (RO) concentrate (ROC) is a critical challenge impeding the application of RO-based wastewater reclamation. Herein, we proposed an enhanced biotreatment approach for the simultaneous removal of nitrogen, phosphorous, hardness, and methylisothiazolinone (MIT) from ROC by suspended-solid phase cultivation of Scenedesmus sp. LX1. Repeated carrier addition, guided by the developed optimal carrier addition model, efficiently enhanced algal growth and contaminant removal through dynamically controlling the suspended algal density by cell attachment. The maximum algal growth rate (212.2 mg/(L∙d)) increased by 41% compared with the control, and the time needed for reaching the maximum algal biomass (906.7 mg/L) was shortened by 1 d, attributing to the mitigation of density restriction. 91.8% of nitrogen (30.2 mg/L) was removed with 5.5 mg/(L∙d) accelerating removal rate, and phosphate (3.7 mg/L) was completely removed within 1 d. Hardness precursors calcium and inorganic carbon were also removed in large amounts, 268.4 and 128.2 mg/L, respectively. Moreover, suspended-solid phase cultivation significantly mitigated the growth inhibition caused by MIT toxicity, enabled the algae to completely biodegrade MIT of extremely high concentrations (4.7 mg/L and 11.4 mg/L) in a short time. Our results demonstrate the feasibility of suspended-solid phase algal cultivation for simultaneously and effectively removing multiple main contaminants from ROC.

Wireless Single-Electrode Self-Powered Piezoelectric Sensor for Monitoring.

In complex environments, there are often toxic and harmful conditions, and so self-powered sensors that use wireless access have a huge advantage. However, there is still a risk of short circuit for self-powered sensors in harsh environments. A single-electrode self-powered sensor was designed, which can be used to monitor body movements such as walking and running, as well as monitoring the motion of some mechanical devices, such as peristaltic pumps, door, and window switches. By using a threshold delay algorithm, this self-powered sensor can be connected to the phone to warn the phone user to check for theft or illegal intrusion when the door and window are opened. Further research shows that the single-electrode configuration can avoid the short-circuit behavior caused by device damage so that the self-powered sensor can still work even if it is pierced. Therefore, the wireless single-electrode self-powered sensor system has better reliability and is more applicable to harsh environments.

Mechanism and kinetics of methylisothiazolinone removal by cultivation of Scenedesmus sp. LX1.

Methylisothiazolinone (MIT) is a widely used non-oxidizing biocide for membrane biofouling control in reverse osmosis (RO) systems usually with high dosages. However, few investigations have focused on MIT removal through bio-processes, since it is highly bio-toxic. This study proposed a novel biotreatment approach for efficient MIT degradation by Scenedesmus sp. LX1, a microalga with strong resistance capability against extreme MIT toxicity. Results showed that MIT (3 mg/L) could be completely removed within 4 days' cultivation with a half-life of only 0.79 d. Biodegradation was the primary removal mechanism and this metabolic process did not rely on bacterial consortia, soluble algal products secretion or algal growth. The main pathway was proposed as ring cleavage followed by methylation and carboxylation through the identification of MIT transformation products. MIT biodegradation followed the pseudo-first-order kinetics under growth control. A new kinetic model was presented to depict the MIT removal considering algal growth, and this model could be used for generally describing non-nutritive contaminants biodegradation. The algal biodegradation capability was independent of the initial biocide concentration, and MIT removal could be enhanced by increasing the initial algal density. Our results highlight the potential application of algal cultivation for MIT-containing wastewater biotreatment, such as RO concentrate.

An acid and alkali-resistant triboelectric nanogenerator.

With the development of technology, environmental problems have become more and more acute and the use of electronic devices in harsh environments has gradually attracted attention. For example, the friction layer of triboelectric nanogenerators (TENGs) may be contaminated and corroded in harsh environments (such as acidic, alkaline or oily environments), resulting in damage or destruction of the TENGs. In this study, we use electrospinning followed by a sintering process to prepare a super-hydrophobic sintered polyvinyl alcohol-polytetrafluoroethylene (S-PVA-PTFE) composite membrane and general industrial oil-absorbing paper to construct a TENG. The maximum power density of the TENG is 261 mW m-2, it can light up 100 blue LEDs, and can power a variety of small electronic devices. Moreover, after 72 h of soaking the friction layer in a strong acid solution followed by a strong alkali solution, the performance of the TENG has no obvious change. The TENG can work stably in an oily working environment. The TENG provides a novel approach for self-powered sensors that work in harsh environments.

Assessment and mechanisms of microalgae growth inhibition by phosphonates: Effects of intrinsic toxicity and complexation.

The effects of phosphonates, the heavily-used antiscalants in reverse osmosis systems, on microalgae are controversial, although they are harmless to most aquatic organisms. Herein, we assessed the inhibitory effects of etidronic acid (HEDP) and diethylenetriamine penta(methylene phosphonic acid) (DTPMP) on algal growth and revealed the mechanisms involved in both intrinsic toxicity and complexation. The phosphonates showed weak influences on Scenedesmus sp. LX1 in the first 4 d of cultivation. In contrast, a significant growth inhibition was observed subsequently with half maximal effective concentrations of 57.6 and 35.7 mg/L for HEDP and DTPMP, respectively, at 10 d. The phosphonates had little effect on cellular energy transfer and oxidative stress, quantified by adenosine triphosphate level and superoxide dismutase activity, respectively, demonstrating weak intrinsic toxicities to algal cells. Phosphonates blocked the algal assimilation of iron ions through complexation. Severe iron deficiency limited photosynthetic activity and caused chlorophyll decline, resulting in a functional loss of the photosystem followed by complete algal growth inhibition at the late cultivation stage. Our findings point to a potential ecological impact wherein harmful algal blooms are induced by the natural degradation of phosphonates due to the release of both iron and phosphate ions that stimulate algal regrowth after disinhibition.