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Self-Assembled Nanostructures of Red Fluorescent Amphiphilic Block Copolymers as Both Imaging Probes and Drug Carriers
摘要： We report a red-?uorescent drug delivery system formed by biodegradable and biocompatible amphiphilic A-B-A block copolymers. Each polymer consists of a red ?uorescent dye covalently bonded in the middle of hydrophobic block (B) of polylactone, tethered at both ends with poly[(oligo ethylene glycol) methyl ether methacrylate] (POEGMA) as the hydrophilic block. Two types of polylactones, i.e., semicrystalline poly(ε-caprolactone) (PCL) and amorphous poly(δ-decalactone) (PDL), respectively, were incorporated as the hydrophobic segment in the block copolymers. Using transmission electron microscopy, we characterized the self-assembled nanostructures formed by these amphiphilic block copolymers in mixtures of water/tetrahydrofuran or water/dimethylformamide. All of these polymers remained highly ?uorescent in water, although some extent of aggregation-induced ?uorescence quenching was still observed. Among the three types of polymers presented here, the polymer (RPO-3) containing an amorphous block of PDL showed the highest drug-loading capacity and the largest extent of drug release in acidic media. RPO-3 micelles loaded with doxorubicin as a model of anticancer drug showed sustainable intracellular release and cytotoxicity against HeLa cells.
关键词： self-assembly,drug delivery,polymer,?uorescence,bioimaging
更新于2025-11-21 11:08:12
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Lysosome-Targeted Single Fluorescence Probe for Two-Channel Imaging Intracellular SO2 and Biothiols
摘要： As the members of reactive sulfur species, SO2 and biothiols play a signi?cant role in physiological and pathological processes and directly in?uence numerous diseases. Furthermore, SO2 and biothiols can provide a reductive environment for lysosomes to carry out their optimal functionality. To this end, the development of single ?uorescent probes for imaging SO2 and biothiols from different emission channels is highly desirable for understanding their physiological nature. Here, a lysosome-targeted ?uorescent probe (BPO-DNSP) with a dual reaction site for SO2 and biothiols was presented. BPO-DNSP can sensitively and selectively respond to SO2 in the green channel with a large Stokes shift over 105 nm, and to biothiols in the near-infrared emission channel with a large Stokes shift over 109 nm. The emission shift for the two channels was as high as 170 nm. Colocalization experiments veri?ed that BPO-DNSP can selectively enrich lysosomes. Notably, BPO-DNSP can not only be used to image intracellular SO2 and biothiols from two different channels, but also to monitor the conversion of biothiols to SO2 without adding exogenous enzymes in living HeLa cells.
关键词： ?uorescence imaging,lysosome-targeted,single ?uorescent probe,biothiols,SO2
更新于2025-11-21 11:08:12
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A Label-Free Fluorescent DNA Machine for Sensitive Cyclic Amplification Detection of ATP
摘要： In this study, a target recycled ampli?cation, background signal suppression, label-free ?uorescent, enzyme-free deoxyribonucleic acid (DNA) machine was developed for the detection of adenosine triphosphate (ATP) in human urine. ATP and DNA fuel strands (FS) were found to trigger the operation of the DNA machine and lead to the cyclic multiplexing of ATP and the release of single stranded (SS) DNA. Double-stranded DNA (dsDNA) was formed on graphene oxide (GO) from the combination of SS DNA and complementary strands (CS(cid:48)). These double strands then detached from the surface of the GO and in the process interacted with PicoGreen dye resulting in amplifying ?uorescence intensity. The results revealed that the detection range of the DNA machine is from 100 to 600 nM (R2 = 0.99108) with a limit of detection (LOD) of 127.9 pM. A DNA machine circuit and AND-NOT-AND-OR logic gates were successfully constructed, and the strategy was used to detect ATP in human urine. With the advantage of target recycling ampli?cation and GO suppressing background signal without ?uorescent label and enzyme, this developed strategy has great potential for sensitive detection of different proteins and small molecules.
关键词： cyclic ampli?cation,ATP detection,DNA machine,label-free ?uorescence,graphene oxide,logic gate
更新于2025-11-19 16:46:39
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Highly Sensitive and Selective Fluorescent Detection of Gossypol Based on BSA-Stabilized Copper Nanoclusters
摘要： In this paper, ?uorescent copper nanoclusters (NCs) are used as a novel probe for the sensitive detection of gossypol for the ?rst time. Based on a ?uorescence quenching mechanism induced by interactions between bovine serum albumin (BSA) and gossypol, ?uorescent BSA-Cu NCs were seen to exhibit a high sensitivity to gossypol in the range of 0.1–100 μM. The detection limit for gossypol is 25 nM at a signal-to-noise ratio of three, which is approximately 35 times lower than the acceptable limit (0.9 μM) de?ned by the US Food and Drug Administration for cottonseed products. Moreover, the proposed method for gossypol displays excellent selectivity over many common interfering species. We also demonstrate the application of the present method to the measurement of several real samples with satisfactory recoveries, and the results agree well with those obtained using the high-performance liquid chromatography (HPLC) method. The method based on Cu NCs offers the followings advantages: simplicity of design, facile preparation of nanomaterials, and low experimental cost.
关键词： probe,?uorescence,copper nanoclusters,gossypol
更新于2025-11-14 17:04:02
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Mercury Free Microscopy: An Opportunity for Core Facility Directors
摘要： Mercury Free Microscopy (MFM) is a new movement that encourages microscope owners to choose modern mercury free light sources to replace more traditional mercury based arc lamps. Microscope performance is enhanced with new solid state technologies because they offer a more stable light intensity output and have a more uniform light output across the visible spectrum. Solid state sources not only eliminate mercury but also eliminate the cost of consumable bulbs (lifetime (cid:2)200 hours), use less energy, reduce the instrument down time when bulbs fail and reduce the staff time required to replace and align bulbs. With lifetimes on the order of tens of thousands of hours, solid state replacements can pay for themselves over their lifetime with the omission of consumable, staff (no need to replace and align bulbs) and energy costs. Solid state sources are also sustainable and comply with institutional and government body mandates to reduce energy consumption, carbon footprints and hazardous waste. MFM can be used as a mechanism to access institutional ?nancial resources for sustainable technology through a variety of stakeholders to defray the cost to microscope owners for the initial purchase of solid state sources or the replacement cost of mercury based sources. Core facility managers can take a lead in this area as “green” ambassadors for their institution by championing a local MFM program that will save their institution money and energy and eliminate mercury from the waste stream. Managers can leverage MFM to increase the visibility of their facility, their impact within the institution, and as a vital educational resource for scienti?c and administrative consultation.
关键词： funding opportunities,?uorescence imaging,light engines,light source
更新于2025-09-23 15:23:52
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Research on Spatially Adaptive High-Order Total Variation Model for Weak Fluorescence Image Restoration
摘要： Confocal laser scanning microscopy (CLSM) has emerged as one of the most advanced ?uorescence cell imaging techniques in the ?eld of biomedicine. However, ?uorescence cell imaging is limited by spatial blur and additive white noise induced by the excitation light. In this paper, a spatially adaptive high-order total variation (SA-HOTV) model for weak ?uorescence image restoration is proposed to conduct image restoration. The method consists of two steps: optimizing the deconvolution model of the ?uorescence image by the generalized Lagrange equation and alternating direction method of multipliers (ADMM); using spatially adaptive parameters to balance the image ?delity and the staircase e?ect. Finally, an comparison of SA-HOTV model and Richardson-Lucy model with total variation (RL-TV model) indicates that the proposed method can preserve the image details ultimately, reduce the staircase e?ect substantially and further upgrade the quality of the restored weak ?uorescence image.
关键词： weak ?uorescence,spatially adaptive high-order total variation (SA-HOTV),image restoration,confocal microscopy
更新于2025-09-23 15:23:52
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Characterization of a novel silicon-containing hybrid polymer by thermal curing, pyrolysis behavior, and fluorescence analysis
摘要： A novel linear silicon-containing hybrid polymer with C C and Si H linkages, diphenyl-dihydroethynyl-silane (DPHES), had been conveniently synthesized and well characterized. The thermal curing, crosslinked structure and pyrolysis behavior were studied by DSC, Fourier transform infrared (FTIR), and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results suggest the crosslinked structures consist mainly of phenyl and aromatic fused rings, which are formed through cyclotrimerization, addition reaction, and hydrosilylation reaction. The thermal properties indicate that the crosslinked DPHES exhibits excellent thermal stability with the temperature at 5% weight loss are higher than 572 and 509 (cid:1)C under nitrogen and air atmosphere, respectively. The ?uorescence emission spectra show DPHES and its crosslinked product also have moderate ?uorescence properties, emitting purple light, and visible blue light, respectively, which further veri?ed the structure of DPHES. These results suggest that DPHES has the potential to be used as light-emitting materials with excellent thermal properties.
关键词： silicon-containing hybrid polymer,?uorescence property,pyrolysis behavior,thermal curing
更新于2025-09-23 15:22:29
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Improving Diagnosis of Cervical Pre-Cancer: Combination of PCA and SVM Applied on Fluorescence Lifetime Images
摘要： We report a signi?cant improvement in the diagnosis of cervical cancer through a combined application of principal component analysis (PCA) and support vector machine (SVM) on the average ?uorescence decay pro?le of Fluorescence Lifetime Images (FLI) of epithelial hyperplasia (EH) and CIN-I cervical tissue samples, obtained ex-vivo. The fast and slow components of double exponential ?tted ?uorescence lifetimes were found to be higher for EH compared to the lifetimes of CIN-I samples. Application of PCA to the average time-resolved ?uorescence decay pro?les showed that the 2nd PC, in combination with 1st PC, enhanced the discrimination between EH and CIN-I tissues. Fluorescence lifetime and PC scores were then classi?ed separately by using SVM support vector machine to identify the two. On applying SVM to a combination of ?uorescence lifetime and PC scores, diagnostic capability improved signi?cantly.
关键词： PCA,?uorescence lifetime,SVM,PC scores
更新于2025-09-23 15:22:29
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Use of Sun-Induced Chlorophyll Fluorescence Obtained by OCO-2 and GOME-2 for GPP Estimates of the Heihe River Basin, China
摘要： Sun-induced chlorophyll ?uorescence (SIF) provides a new method for monitoring vegetation photosynthesis from space and has been widely used to estimate gross primary productivity (GPP). However, the ability of SIF obtained from the Orbital Carbon Observatory 2 (OCO-2 SIF) and Global Ozone Monitoring Experiment-2 (GOME-2) to estimate GPP in the cold and arid region of Heihe River Basin remains unclear because previous comparisons were insuf?cient. Here, we choose maize and alpine meadow to evaluate the performance of SIF obtained by OCO-2 and GOME-2 in GPP estimations. The results of this study show that daily SIF757 had stronger correlations with daily tower GPP than daily SIF771, and the correlation between daily SIF757 and daily tower GPP was stronger than the correlation between 16-d averaged SIF740 and 16-d averaged tower GPP. The 16-d averaged absorbed photosynthetically active radiation (APAR) and reconstructed sun-induced ?uorescence (RSIF) had the strongest linear correlations with 16-d averaged tower GPP. GPP_VPM and GPP_RSIF exhibited the best performance in GPP estimation, closely followed by GPP_SIF757, then GPP_SIF771 and GPP_ SIF740. We also found that the robustness of the correlation coef?cients of OCO-2 SIF with GOME-2 SIF was highly dependent on the size of their spatial footprint overlaps, indicating that the spatial differences between OCO-2 and GOME-2 footprints contribute to the differences in GPP estimates between OCO-2 and GOME-2. In addition, the differences of viewing zenith angle (VZA), cloud contamination, scale effects, and environmental scalars (Tscalar × Wscalar) can result in differences between OCO-2 SIF and GOME-2 SIF.
关键词： vegetation photosynthesis model,eddy covariance,sun-induced ?uorescence,gross primary productivity,carbon cycle
更新于2025-09-23 15:22:29
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Quantification of Cellular Proteostasis in Live Cells by Fluorogenic Assay Using the AgHalo Sensor
摘要： Proper cellular proteostasis is essential to cellular ?tness and viability. Exogenous stress conditions compromise proteostasis and cause aggregation of cellular proteins. We have developed a ?uorogenic sensor (AgHalo) to quantify stress-induced proteostasis de?ciency. The AgHalo sensor uses a destabilized HaloTag variant to represent aggregation-prone cellular proteins and is equipped with a series of ?uorogenic probes that exhibit a ?uorescence increase when the sensor forms either soluble oligomers or insoluble aggregates. Herein, we present protocols that describe how the AgHalo sensor can be employed to visualize and quantify proteome stress in live cells using a direct ?uorescence read-out and visualization with a ?uorescence microplate reader and a microscope. Additionally, protocols for using the AgHalo sensor in combination with ?uorogenic probes and commercially available HaloTag probes to enable two-color imaging experiments are described. These protocols will enable use of the AgHalo sensor to visualize and quantify proteostasis in live cells, a task that is dif?cult to accomplish using previous, always-?uorescent methods.
关键词： protein aggregation,?uorescence intensity,proteostasis,?uorogenic sensor
更新于2025-09-23 15:21:21