Biological Stability Research Articles

Changes in Main Parameters of Biological Stabilisation of Municipal Waste from a Full-Scale Mechanical-Biological Treatment (MBT) Installation

Abstract Poland's mixed municipal waste management system has been based on mechanical-biological treatment (MBT). One of the MBT processes is the biological stabilisation of fractions of less than 80 mm. The final product after biological stabilisation is a stabiliser that, once the conditions required by law are met, can be landfilled. The stabilizer must meet the following requirements: the loss of ignition (LOI) of the stabiliser is less than 35% DM, the organic carbon content is less than 20% DM and the AT4 value (aerobic 4-day respiration test) value is less than 10 mgO2/g DM. The study aimed to analyse the changes that occurred during the first 4 weeks of biological processing of the fraction of less than 80 mm of mixed municipal waste. The bioreactor feedstock consisted of 41.7% organic fraction (OF), the LOI was 32.3%, and the AT4 value was 45.7 mgO2/g DM. During biological processing, at 4 weeks, the loss of OF in the total weight of the waste was found to be 22.6%, the losses after roasting decreased by almost 90% and the value of AT4 was 6.6 mgO2/g DM. This means that the stabiliser already after 4 weeks, according to the law, could be sent to a landfill.

A Bio‐Inspired Trehalose Additive for Reversible Zinc Anodes with Improved Stability and Kinetics

AbstractThe moderate reversibility of Zn anodes, as a long‐standing challenge in aqueous zinc‐ion batteries, promotes the exploration of suitable electrolyte additives continuously. It is crucial to establish the absolute predominance of smooth deposition within multiple interfacial reactions for stable zinc anodes, including suppressing side parasitic reactions and facilitating Zn plating process. Trehalose catches our attention due to the reported mechanisms in sustaining biological stabilization. In this work, the inter‐disciplinary application of trehalose is reported in the electrolyte modification for the first time. The pivotal roles of trehalose in suppressed hydrogen evolution and accelerated Zn deposition have been investigated based on the principles of thermodynamics as well as reaction kinetics. The electrodeposit changes from random accumulation of flakes to dense bulk with (002)‐plane exposure due to the unlocked crystal‐face oriented deposition with trehalose addition. As a result, the highly reversible Zn anode is obtained, exhibiting a high average CE of 99.8 % in the Zn/Cu cell and stable cycling over 1500 h under 9.0 % depth of discharge in the Zn symmetric cell. The designing principles and mechanism analysis in this study could serve as a source of inspiration in exploring novel additives for advanced Zn anodes.

A Bio-Inspired Trehalose Additive for Reversible Zinc Anodes with Improved Stability and Kinetics.

The moderate reversibility of Zn anodes, as a long-standing challenge in aqueous zinc-ion batteries, promotes the exploration of suitable electrolyte additives continuously. It is crucial to establish the absolute predominance of smooth deposition within multiple interfacial reactions for stable zinc anodes, including suppressing side parasitic reactions and facilitating Zn plating process. Trehalose catches our attention due to the reported mechanisms in sustaining biological stabilization. In this work, the inter-disciplinary application of trehalose is reported in the electrolyte modification for the first time. The pivotal roles of trehalose in suppressed hydrogen evolution and accelerated Zn deposition have been investigated based on the principles of thermodynamics as well as reaction kinetics. The electrodeposit changes from random accumulation of flakes to dense bulk with (002)-plane exposure due to the unlocked crystal-face oriented deposition with trehalose addition. As a result, the highly reversible Zn anode is obtained, exhibiting a high average CE of 99.8 % in the Zn/Cu cell and stable cycling over 1500 h under 9.0 % depth of discharge in the Zn symmetric cell. The designing principles and mechanism analysis in this study could serve as a source of inspiration in exploring novel additives for advanced Zn anodes.

Synthesis and Characterization of Thiol-Protected Silver Nanoclusters for Photodynamic Therapy Applications

Aqueous metal nanoclusters have emerged as versatile tools in biomedical applications, particularly in the scope of imaging and cancer therapeutics. This research paper investigates a thiol-protected silver nanocluster (AgNC), focusing on establishing a reproducible synthesis method to obtain a pure cluster species for use in biological stability studies. Conventionally, nanocluster synthesis employs reducing agents, like NaBH4, which often poses challenges in reaction control and product purity. This study adopts an alternative approach, utilizing a Norrish Type I reaction to enhance synthesis. This light-activated reaction leverages the regulated concentration of alpha-hydroxy radicals from a photoinitiator (Omnirad 2959) achieved through UVA-induced homolytic bond cleavage. Monitoring AgNC formation through ultraviolet-visible (UV-Vis) and fluorescence emission-excitation matrix (EEM) spectroscopy and confirming product purity via parallel factor analysis (PARAFAC), this work offers insight into the influence of parameters such as light intensity, reactant concentration, irradiation wavelength, and oxygen presence on consistency and reproducibility of the AgNC syntheses. Methods like Polyacrylamide Gel Electrophoresis (PAGE) and centrifugation are also employed to facilitate separation and purification, preparing the AgNC for subsequent evaluation within biologically significant contexts (tumor microenvironments and phosphate buffer solutions). Although diverse reaction conditions yielded an array of nanocluster species, characterization of the AgNCs reveals challenges in reproducing a pure cluster species consistently. EEM and PARAFAC analyses underscore similarities across synthesized clusters, yet significant variations in reaction conditions persist. The primary application envisioned for these AgNCs is in Photodynamic Therapy (PDT), a form of radiative therapy that exploits the optical properties of metal nanoclusters to induce reactive oxygen species, thus eliciting cancer cell death. It is evident that further investigation is necessary to deepen the comprehension of AgNCs and validate their potential use in PDT. Future research should focus on refining reaction conditions, and effective separation, of AgNC, allowing for advancement in therapeutic interventions such as PDT.

The effect of tail stiffness on a sprawling quadruped locomotion.

A distinctive feature of quadrupeds that is integral to their locomotion is the tail. Tails serve many purposes in biological systems, including propulsion, counterbalance, and stabilization while walking, running, climbing, or jumping. Similarly, tails in legged robots may augment the stability and maneuverability of legged robots by providing an additional point of contact with the ground. However, in the field of terrestrial bio-inspired legged robotics, the tail is often ignored because of the difficulties in design and control. In this study, we test the hypothesis that a variable stiffness robotic tail can improve the performance of a sprawling quadruped robot by enhancing its stability and maneuverability in various environments. In order to validate our hypothesis, we integrated a cable-driven, flexible tail with multiple segments into the underactuated sprawling quadruped robot, where a single servo motor working alongside a reel and cable mechanism regulates the tail's stiffness. Our results demonstrated that by controlling the stiffness of the tail, the stability of locomotion on rough terrain and the climbing ability of the robot are improved compared to the movement with a rigid tail and no tail. Our findings highlight that constant ground support provided by the flexible tail is key to maintaining stable locomotion. This ensured a predictable gait cycle, eliminating unexpected turning and slipping, resulting in an increase in locomotion speed and efficiency. Additionally, we observed the robot's enhanced climbing ability on surfaces inclined up to 20°. The flexibility of the tail enabled the robot to overcome obstacles without external sensing, exhibiting significant adaptability across various terrains.

Oxidized Xanthan Gum Crosslinked NOCC: Hydrogel System and Their Biological Stability From Oxidation Levels of the Polymer.

Dynamic hydrogel systems from N,O-carboxymethyl chitosan (NOCC) have been investigated in the past years which has facilitated their widespread use in many biomedical engineering applications. However, the influence of the polymer's oxidation levels on the hydrogel biological properties has not been fully investigated. In this study, chitosan was converted into NOCC and introduced to react spontaneously with oxidized xanthan gum (OXG) to form several injectable hydrogels with controlled degradability. Different oxidation levels of xanthan gum, as well as NOCC/OXG volume ratios, were trialed. The infrared spectroscopy spectra verified chemical modification on OXG and successful crosslinking. With increasing oxidation levels, more dialdehyde groups were introduced into the OXG, resulting in changes in physical properties including gelation, swelling, and self-healing efficiency. Under different volume ratios, the hydrogel showed a stable structure and rigidity with higher mechanical properties and a slower degradation rate. The shear-thinning and self-healing properties of the hydrogels were confirmed. In vitro assays with L929 cells showed the biocompatibility of all formulations although the use of a high amount of OXG15 and OXG25 limited the cell proliferation capacity. Findings in this study suggested a suitable amount of OXG at different oxidation levels in NOCC hydrogel systems for tissue engineering applications. This article is protected by copyright. All rights reserved.

Behavior of deteriogenic fungi in aviation fuels (fossil and biofuel) during simulated storage.

Biofuels are expected to play a major role in reducing carbon emissions in the aviation sector globally. Farnesane ("2,6,10-trimethyldodecane") is a biofuel derived from the synthesized iso-paraffin route wich can be blended with jet fuel; however, the microbial behavior in farnesane/jet fuel blends remains unknown. The chemical and biological stability of blends should be investigated to ensure they meet the quality requirements for aviation fuels. This work aimed at evaluating the behavior of two fungi Hormoconis resinae (F089) and Exophiala phaeomuriformis (UFRGS Q4.2) in jet fuel, farnesane, and in 10% farnesane blend during simulated storage. Microcosms (150-mL flasks) were assembled with and without fungi containing Bushnell & Haas mineral medium for 28 days at a temperature of 20±2°C. The fungal growth (biomass), pH, surface tension, and changes in the fuel's hydrocarbon chains were evaluated. This study revealed thatthe treatment containing H. resinae showed a biomass of 19 mg, 12 mg, and 2 mg for jet fuel, blend, and farnesane respectively. The pH was reduced from 7.2 to 4.3 observed in jet fuel treatment The degradation results showed that compounds with carbon chains between C9 and C11, in jet fuel, and blend treatments were preferably degraded. The highest biomass (70.9 mg) produced by E. phaeomuriformis was in 10% farnesane blend, after 21 days. However, no significant decrease was observed on pH and surface tension measurements across the treatments as well as on the hydrocarbons when compared to the controls. This study revealed that farnesane neither inhibited nor promoted greater growth on both microorganisms.

Modification of Marine Bioactive Peptides: Strategy to Improve the Biological Activity, Stability, and Taste Properties

Modification of Marine Bioactive Peptides: Strategy to Improve the Biological Activity, Stability, and Taste Properties

Twelve-Month Clinical and Histopathological Performance of a Novel Synthetic Cornea Device in Rabbit Model.

To report the biological stability and postoperative outcomes of a second-generation, single-piece, flexible synthetic cornea in a rabbit model. Device materials and design were amended to enhance biointegration. Optic skirt design devices were made from compact perfluoroalkoxy alkane with porous expanded polytetrafluoroethylene ingrowth surface overlying the skirt and optic wall. Sixteen devices were implanted into intrastromal pocket in rabbit eyes. Rabbits were randomly assigned to 6- and 12-month follow-up cohorts (n = 8 in each) postoperatively. Monthly examinations and optical coherence tomography assessed cornea-device integration, iridocorneal angle, optic nerve, and retina. There were no intraoperative complications. All devices were in situ at exit, with clear optics. No retroprosthetic membrane, glaucoma, cataract formation, or retinal detachment was observed. Two rabbits in the 6-month group had mild, focal anterior lamella thinning without retraction adjacent to the optic near tight sutures. Three postoperative complications occurred in the 12-month group. One rabbit diagnosed with endophthalmitis was euthanized on day 228. Mild sterile focal retraction of anterior lamella occurred in two rabbits, which were terminated on days 225 and 315. Light microscopic examination of enucleated globes demonstrated fibroplasia with new collagen deposition into the porous scaffold without significant inflammation, encapsulation, or granuloma formation. Clinical evaluations, imaging, and histopathological findings indicate favorable outcomes of this synthetic corneal device in a rabbit model. Early feasibility studies in humans are being planned. Favorable 12-month results of the device in rabbits demonstrate vision-restoring potential in corneally blind individuals at high risk of failure with donor keratoplasty.

Functional nucleic acids with synthetic sugar or nucleobase moieties

Functional nucleic acids including aptamers and DNAzymes are a class of valuable molecular tool for biotechnology. However, DNA and RNA aptamers and catalysts suffer from low biological stability and limited chemical diversity. Xeno-nucleic acids (XNAs) refer to nucleic acid analogues containing sugar moieties that are structurally distinct from DNA and RNA and possess advantageous properties. In this article, we first focus on two types of XNAs, threose nucleic acid (TNA) and 2’-fluoroarabinose nucleic acid (FANA), and summarize recent in vitro selections of TNA and FANA aptamers and catalysts. We then review three classes of unnatural base pairs (UBPs) and highlight examples of UBP-containing DNA aptamers and DNAzymes. Lastly, we briefly describe an XNA-modified DNAzyme 10–23 (X10-23) and its application in RNA knockdown and virus detection. Functional XNAs provide important chemical biology tools for biomedical research and future interdisciplinary collaboration will boost XNA basic research and clinical translation.

Surface modification potentials of cell membrane-based materials for targeted therapies: a chemotherapy-focused review.

Nanotechnology has significant potential for cancer management at all stages, including prevention, diagnosisand treatment. In therapeutic applications, nanoparticles (NPs) have biological stability, targetingand body-clearance issues. To overcome these difficulties, biomimetic or cell membrane-coating methods using immune cell membranes are advised. Macrophage or neutrophil cell membrane-coated NPs may impede cancer progression in malignant tissue. Immune cell surface proteins and their capacity to maintain activity after membrane extraction and NP coating determine NP functioning. Immune cell surface proteins may offer NPs higher cellular interactions, blood circulation, antigen recognition for targeting, progressive drug releaseand reduced in vivo toxicity. This article examines nano-based systems with immune cell membranes, their surface modification potential, and their application in cancer treatment.

Toplam Biyolojik Yük Sayısı için Kontrol Tablosu Yaklaşımını Kullanarak Belediye Dağıtım Hattının Mikrobiyolojik Stabilite Değerlendirmesi

Background: The microbiological quality of municipal water is an important inspection characteristic that must be carefully monitored and controlled to ensure the delivery of acceptable water that is safe for human activities, consumption and further processing. Case presentation: The current case demonstrated the implementation of a special type of attribute control chart for the examination and analysis of long-term data trends of water distribution in a healthcare facility from different pints-of-use. All datasets showed a right-skewed dispersion pattern of data indicating solitary intermittent high values but without any observable Out-Of-Specification (OOS). All water lines failed to follow any known distribution pattern without the need for transformation which had improved the normality and removed the outliers from datasets. The direct approach for visualizing the record of microbiological results was accomplished using Laney-attribute charts. Discussion: Each use point had its unique trend of data by visualizing the mean, pattern, the Upper Control Limit (UCL) and the alarm types. The net quality of the water distribution system in the facility could be deduced from the overall readings that had been averaged and pooled in a single process-behavior chart. Implementation of this trending chart showed a tendency of oscillation pattern for bioburden count that tended to seize in amplitude with possible signs of seasonality. Conclusion: In general, the overall biological stability is improving with time in terms of the Total Microbial Aerobic Count (TAMC). The Bioburden level and the magnitude of fluctuations were decreasing according to the latest monitoring state.

A Hardware-Friendly Real-Time Implementation of the Auditory Attention Based on a Novel Spiking Winner-Take-All Network

In recent decades, the modeling and designing of neuromorphic systems have received considerable attention, leading to the development of electrophysiological devices that can mimic the dynamic behavior of cortical networks. Some features such as parallel processing, real-time performance, reconfigurability, low production cost, and good accuracy, make field programmable gate arrays (FPGAs) an ideal hardware platform for implementing spiking neural networks (SNN), which has become very popular in the field of neural computing. In this work, we investigated a high-performance FPGA design of the auditory attention to simulate the on-chip ‘cocktail party’ effect similar to what happens in the brain. In the first step, we introduce a novel spiking winner-take-all (SWTA) network consisting of a hardware-friendly Izhikevich neuron model and explore its biological characteristics and stability. We then use this network as a receptive field in the primary auditory cortex, which is tuned by attention signals. The desired sound frequency will be selected as the target and transmitted to the higher layers of the auditory cortex for further processing, while other frequencies are severely suppressed. Experimental results show that the proposed network accurately follows the dynamic behavior defined in the auditory attention theory, and emphasizes the resource consumption after post place and routes on a fully efficient hardware implementation, where less than 4% of the resources were used to implement a network with 1856 neurons.

Exogenous silicon alleviates salinity stress in fenugreek (Trigonella foenum-graecum L.) by enhancing photosystem activities, biological nitrogen fixation and antioxidant defence system

Silicon (Si) application has emerged as a promising solution to improve plant growth under stressful conditions. However, the mechanisms by which Si alleviated salt damage, especially on photosynthetic machinery and symbiosis establishment in legume plants are not fully understood. Thus, this research was designed to investigate the beneficial effects of Si-treatment on salt stress tolerance in fenugreek (Trigonella foenum graecum L.). Fenugreek plants were exposed to 150 mM NaCl with or without 3 mM Si, to evaluate the effects of Si on photosynthetic traits, biological nitrogen fixation (BNF), membrane stability and oxidative stress metabolism. Results indicated that salinity significantly decreased plant growth in terms of plant biomass and high, relative water content and photosynthetic traits, including chlorophyll content and photosystems (PSI and PSII) functions, whereas the treatment of salt-stressed fenugreek with exogenous Si remarkably improved the same traits. As compared to salt-stressed control, the fenugreek-rhizobia symbiosis was also improved under salt stress in response to Si supplementation, reflected by higher nodule number and nitrogen content. On the other hand, Si supplementation to salt-stressed fenugreek plants lead to a significant decline in malonyldialdehyde and hydrogen peroxide in both shoot and root, indicating the protective effect of Si on membrane stability. This was shown to be related to the ability of Si to boost the activities of superoxide dismutase, catalase and guaiacol peroxidase. This research suggests the protective role of Si on salt-stressed fenugreek by enhancing photosynthesis, BNF and oxidative stress metabolism.

Impact of Double Time Delays on Regime Shift and Stochastic Resonance for a Species Population System Driven by Colored Correlated Multiplicative and Additive Noises

In this paper, the characteristics for the state transition between the boom state and the extinction one, varius stochastic resonance (SR) phenomena for a species population system induced by double time delays and colored cross-correlated Gaussian noises are investigated. The control of the species population system has an important effect on ecological balance and the development of human living environment. By means of the numerical calculation of the mean extinction time and the stationary probability density function (SPDF), we can figure out some fact: both external and internal noises, the noise correlation strength and its correlation time, one time delay can all reduce the ecological stability and shorten the survival time of the system; while the other time delay can enhance significantly the biological stability and postpone the extinction of the population. For the mean extinction time (MET) of the species population, it is found that noise correlation strength, time delay, the noise correlation time can all reduce the peak value of the MET, which leads to the reduction of the life cycle. Inversely, the other time delay will not change the maximum of the MET, and induce the peak value to shift to the left. With respect to the SNR, it is discovered that in the noise correlation strength and its correlation time, one-time delay mainly plays a prominent role in inhibiting the SR effect. On the contrary, the multiplicative noise can result in the enhancement of the resonant peak. In particular, the other time delay and the additive noise can stimulate the SR effect for the SNR during the initial period. However, the further increase of them will bring about the reduction of the resonant phenomenon.

Recent advancement in bioeffect, metabolism, stability, and delivery systems of apigenin, a natural flavonoid compound: challenges and perspectives.

Apigenin is a bioflavonoid compound that is widely present in dietary plant foods and possesses biological activities that protect against immune, cardiovascular, and neurodegenerative diseases and cancer. Therefore, apigenin is widely used in food and medicine, and increasing attention has been drawn to developing new delivery systems for apigenin. This review highlights the biological effects, metabolism, stability, and bioactivity of apigenin. In addition, we summarized advancements in the delivery of apigenin, which provides some references for its widespread use in food and medicine. Better stability of apigenin may enhance digestion and absorption and provide health benefits. Constructing delivery systems (such as emulsions, nanostructured lipid carriers, hydrogels, and liposomes) for apigenin is an effective strategy to improve its bioavailability, but more animal and cell experiments are needed to verify these findings. Developing apigenin delivery systems for food commercialization is still challenging, and further research is needed to promote their in-depth development and utilization.

Assessing the impact of urban land expansion on ecosystem carbon storage: A case study of the Changzhutan metropolitan area, China

The extension of urban development can encroach onto ecologically important land, such as forests and farmland, and have a significant impact on regional ecosystem carbon storage. Although there has been extensive research on the carbon storage response to land use changes, limited exploration has been conducted on the changes in ecosystem carbon storage resulting from the expansion of construction land.. In the current research, we analyzed the characteristics involved in the growth related to built-up space in the Changzhutan metropolitan area from 1990 to 2020. Using the InVEST model, we evaluated the resulting effects on ecological carbon sequestration, and using the PLUS model, we simulated the effects of building land expansion under four scenarios: natural development, farmland protection, ecological protection, and comprehensive development. Additionally, our aim was to quantify the possible implications of the development of built-up areas on regional carbon storage. (1) The Changzhutan metropolitan area expanded its construction land by 721.58 km2 from 1990 to 2020, with the expansion mainly concentrated in the urban fringe areas, and the land type mainly changed from forests and farmland to construction land. (2) The ecosystem carbon sequestration in the Changsha-Zhuzhou-Xiangtan metropolitan area decreased by 22.66 × 106 t from 1990 to 2020, with the most significant decrease occurring from 2005 to 2010 when the expansion of construction land was 284.43 km2. (3)By 2030, the Changzhutan metropolitan area is projected to expand its construction land by 312.05 km2, 175.65 km2, 68.21 km2, and 68.90 km2 under the scenarios of natural development, farmland protection, ecological protection, and comprehensive development, respectively. Land use change in each scenario is expected to cause carbon storage losses of 10.01 × 106 t, 11.01 × 106 t, 2.07 × 106 t, and 1.95 × 106t, compared to 2020. (4) Over the investigation time span, expansion of construction ground in metropolitan Changzhutan had a negative impact on regional carbon storage, reaching a stable state from 2005 to 2020, and the effect pertaining to growth from the area of development upon the carbon accumulation of regional ecosystems under the comprehensive protection scenario in 2030 was −0.46. Considering the spatial heterogeneity analysis of regional carbon storage, this scenario would substantially upgrade the functional area surrounding the region and increase the biological system stabilization, which is conducive to achieving carbon neutrality goals.

Bioprinting of bioglass-alginate/carboxymethyl cellulose for bone tissue engineering

Bone regenerative medicine requires suitable substitutes that promote osteogenesis. Most of the bio-macromolecular hydrogels are promising because they are biocompatible and biodegradable, but their viscoelastic properties make them challenging to use, especially in 3D bioprinting applications. This study aimed to enhance the mechanical properties of a bone substitute made of bioprinted alginate, carboxymethyl cellulose, and 58S bioglass. We used dual cross-linking and optimized the concentration of cross-linking agents to improve hydrogel biological activity and mechanical stability. The compression test indicated that the combination of Ca2+ and Fe3+ significantly improved the mechanical properties of the alginate/carboxymethyl cellulose hydrogel. The hydrogel crosslinked with 4% Ca2+ and 1.5% Fe3+ showed the highest Young's modulus. The study also found that the hydrogel rigidity influenced cell proliferation capability during bioprinting, as observed in the cell viability results. At day 7, the cell viability of the bioprinted constructs cross-linked with 0.5% and 1% Fe3+ exhibited significant increases. Similarly, these groups also demonstrated the highest alkaline phosphatase (ALP) activity at the same time. Results suggested that cross-linking density and resultant rigidity achieved by optimal concentrations of Fe3+ have very significant effects on cell viability and osteogenesis.

Facile construction of drugs loaded lipid-coated calcium carbonate as a promising pH-Dependent drug delivery system for thyroid cancer treatment

To develop innovative drug delivery carriers for controllable release and cancer-targeted delivery of therapeutic agents to accomplish efficient cancer chemotherapy. Herein we effectively fabricated CaCO3 primarily loaded biotin (BT) and directly the self-assembly of oxaliplatin (Pt (IV)) prodrugs form in liposomes. The acquired BT-Pt (IV)@PEG/CaCO3 with outstanding biological stability displays rapid pH-mediated degradations, thus allowing the effective pH-responsive delivery of BT. In vitro, anticancer assays proved that BT-Pt (IV)@PEG/CaCO3 effectively kills the thyroid cancer cells (B-CPAP and FTC-133). The biochemical staining assays investigated the morphological changes of thyroid cancer after treatment with nanoparticles. The DNA fragmentation of the cells was assessed by utilizing the comet assay. BT-Pt (IV)@PEG/CaCO3 increased ROS levels and caused mitochondrial membrane potential and DNA damage, which resulted in apoptosis. Due to its versatile drug-loading capability, this research demonstrates that CaCO3 liposomal formulation is a biocompatible and reliable substrate for establishing pH-mediated drug delivery methods and promising for possible therapeutic application.

An activatable small-molecule fluorogenic probe for detection and quantification of beta-amyloid aggregates

Extracellular accumulation of β amyloid (Aβ) peptides in the brain is thought to be a pathological hallmark and initial event before the symptom starts of Alzheimer’s patients. Herein, we developed two series of benzo[d]thiazole-based small-molecule compounds (BM1-BM4, BPM1-BPM4) with a donor–acceptor (D-A) or donor-π-acceptor (D-π-A) architecture, respectively, based on structure–activity relationship. Among them, the optimized BPM1 not only displayed the highest binding affinity to Aβ aggregates over other proteins or Aβ monomers, but was readily activated its fluorescence with 10-fold fluorescence enhancement, allowing for specifically and sensitively detecting Aβ aggregates. BPM1 also exhibits several other advantages including low molecular weight, low cytotoxicity and excellent biological stability. Besides, cell staining results confirmed that SK-N-BE(2) cells can be fluorescently lighted up as well as cell permeability and damage when treated with BPM1-bound Aβ1-42 aggregates.