- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Label-free protein quantitation by dielectric spectroscopy of dual-frequency liquid crystal
摘要： A dual-frequency-liquid-crystal (DFLC)-based biosensor was developed and its frequency-dependent dielectric properties were exploited to detect and quantitate a protein standard, bovine serum albumin (BSA). By analyzing the dielectric spectra of DFLC in the presence of BSA at various concentrations, we found that the difference in dielectric permittivity between the high- and low-frequency regimes is correlated to BSA concentration, thereby permitting a DFLC-based protein quantitative method. The dielectric properties of DFLCs are fundamental in the design of liquid crystal displays and fast-switching devices. Results from this study demonstrate the extended potential of the frequency-revertible dielectric anisotropy of DFLC in biosensing and protein quantitation.
关键词： Dielectric spectroscopy,Protein,LC-based biosensor,Bovine serum albumin,Dual-frequency liquid crystal
更新于2025-09-09 09:28:46
-
Interactions of Bromocarbazoles with Human Serum Albumin Using Spectroscopic Methods
摘要： The 1,3,6,8-tetrabromocarbazole and 3-bromocarbazole have attracted great attention in the ecotoxicology field recently as hazardous environmental contaminants. In this study, the quenching mechanism of these two substances binding with human serum albumin (HSA) has been investigated with spectroscopic methods. Through fluorescence quenching and binding site experiments with steady-state fluorescence and UV-Vis spectra, the intrinsic fluorescence of HSA quenched by 1,3,6,8-tetrabromocarbazole and 3-bromocarbazole both in static process, are activated by binding to site II (subdomain IIIA) of the HSA. In addition, it was not only found that the conformation and secondary structure of the proteins changes, but also that their spontaneous binding processes were driven by electrostatic interactions as well as hydrophobic forces for HSA-1,3,6,8-tetrabromocarbazole, and by typical hydrophobic forces for HSA-3-bromocarbazole. The above studies are beneficial to enhance our understanding of the ecotoxicology and environmental behaviors of halogenated carbazoles.
关键词： 1,3,6,8-tetrabromocarbazole,3-bromocarbazole,spectroscopic method,site II (subdomain IIIA),human serum albumin
更新于2025-09-09 09:28:46
-
Fluorescence Spectroscopic Studies of in vitro Interactions of Famotidine and Tapentadol Hydrochloride with Bovine Serum Albumin
摘要： The in vitro interactions of Famotidine (FT) and Tapentadol hydrochloride (TAP) with bovine serum albumin (BSA) have been studied by fluorescence emission spectroscopy under different conditions. Quenching constants were determined using the Stern-Volmer equation. Two moles FT bound with 1 mole of BSA at 298 K and 3 mole FT bound with 1 mole of BSA at 308 K in presence of TAP. BSA was used for the study as it shows approximately 76% sequence homology to human serum albumin (HSA).
关键词： in vitro,fluorescence,bovine serum albumin,Famotidine,Tapentadol Hydrochloride,spectroscopy
更新于2025-09-09 09:28:46
-
Quenching of Luminol Fluorescence at Nano-Bio Interface: Towards the Development of an Efficient Energy Transfer System
摘要： Surface modified colloidal gold (Au) and silver (Ag) nanoparticles (NPs) were used as efficient quenchers of luminol (LH2) fluorescence either in homogeneous aqueous medium or its noncovalent assembly with bovine serum albumin (BSA). The mechanism as well as the extent of fluorescence quenching was found to be strongly dependent on the nature of the nanoparticles. While simple static type fluorescence quenching mechanism was perceived with AuNP, a more complex protocol involving quenching sphere model was envisaged for AgNP quenching. Nevertheless, the magnitude of Stern-Volmer (SV) quenching constant (KSV ~ 108–1010 M?1) was calculated to be ca. 104 times more for surface quoted NPs in comparison with BSA–NP bioconjugates system. On the other hand, a highly efficient (E ≈ 95%) energy transfer (ET) process was predicted for LH2 captured in the hydrophobic assembly with BSA in presence of AgNP as an acceptor. The ET efficiency is critically dependent on the concentration of BSA and nicely correlated with the extent of NP surface coverage. However, fluorescence quenching on AuNP surface is relatively less responsive towards protein concentration, primarily due to the difference in surface activity as well as the mode of interaction of the protein with NPs.
关键词： Bionanosensors,Bovine serum albumin,Luminol,Metal nanoparticles,Energy transfer,Fluorescence quenching
更新于2025-09-09 09:28:46
-
Hybrid Nanomaterials of Conjugated Polymers and Albumin for Precise Photothermal Therapy
摘要： Heretofore, conjugated polymers (CPs) attract considerable attention in photothermal therapy (PTT). Although various CPs with different structures have been reported, the suboptimal circulation persistence and biodistribution limit their efficacy in tumor treatment. Human serum albumin (HSA), an endogenous plasm protein, has been widely functioned as a carrier for therapeutic agents. Herein, we construct nanocomplexs C16 pBDP@HSA NPs from hydrophobic 4, 4-difluoro-4-bora-3a, 4adiaza-s-indacene (BODIPY)-containing CPs and HSA, which exhibit robust stability in physiological conditions and excellent photothermal activity upon irradiation. The high photothermal conversion efficiency of 37.5 %, higher than that of other reported PTT agents such as gold nanorods, phosphorus quantum dots and 2D materials, results in the potent photocytotoxicity towards cancer cells. Simultaneously, C16 pBDP@HSA NPs’ capabilities of near infrared fluorescence and photoacoustic imaging can provide guidance to the PTT. The outstanding inhibition of tumor growth results from great photothermal activity, the benefited accumulation in tumor and optimal timing of treatment. To the best of our knowledge, this is the first study which combines the BODIPY-based CPs and HSA in one nanostructure and finds application in cancer treatment. Moreover, this article also offers a new strategy for other insoluble macromolecules to explore more biomedical applications.
关键词： photothermal therapy,albumin,hybrid nanoparticles,conjugated polymers,BODIPY
更新于2025-09-09 09:28:46
-
Media Dependent Switching of Selectivity and Continuous Near Infrared Turn-on Fluorescence Response through Cascade Interactions from Noncovalent to Covalent Binding for Detection of Serum Albumin in Living Cells
摘要： Abnormal level of proteins is proved to be associated with diseases. Thus, protein sensing is helpful for clinical diagnosis and therapy. However, there is a great variety of protein species and relatively low concentration of each protein in complicated biological systems including other non-protein biomolecules. Therefore, it remains challenging to develop an effective method for detecting protein with high selectivity and sensitivity. Herein, a new self-assembly method based on a robust dye SQSS of which two squaraine molecules were conjugated through disulfide bond was developed for highly selective and sensitive detection of serum albumin (SA) in aqueous solution and live cells. SQSS can self-assemble into “compact” aggregates, offering “inert” disulfide group and very low background fluorescence through the combination of aggregation quenching and homogeneous fluorescence resonance energy transfer (homoFRET) quenching. The response of SQSS to SA undergoes two cascade stages. At the first stage, SA drives the compact assemblies of SQSS to form loose ones with fast speed (30 s) through noncovalent interaction, resulting in the enhancement of fluorescence to some extent. In this loose assembly state, the disulfide bond in SQSS is reactive. At the second stage, the Cys34 in SA slowly induced further disassembly through covalent binding with reactive disulfide bond, resulting in fluorescence further increasing and SQSS labeling to SA that cannot be displaced by site binding ligands of SA. The self-assemblies of SQSS can selectively detect SA with continuous near infrared (NIR) turn-on fluorescence response in 100% aqueous buffer solution. In addition, SQSS showed the potential application of imaging SA in living cells. On the other hand, the loose assembly state of SQSS was also achieved in aqueous solution with 20% CH3CN. In this media, thiol-containing glutathione (GSH) caused the disassembly of SQSS with turn-on fluorescence response through interaction with disulfide bond. SQSS can selectively recognize GSH over other amino acids even in the presence of other sulfhydryl amino acids. As a proof-of-concept method, the molecular self-assembly through multi-steps interactions would provide an ideal strategy for detection and live-cell imaging of bio-related molecules with high selectivity and signal-to-noise ratio.
关键词： squaraine dyes,disulfide linkage,glutathione,live-cell imaging,serum albumin,self-assemblies,noncovalent and covalent interactions
更新于2025-09-09 09:28:46
-
Nucleus‐targeted organoiridium‐albumin conjugate for photoactivated cancer therapy
摘要： A novel organoiridium-albumin bioconjugate (Ir1-HSA) was synthesized via reaction of a pendant maleimide ligand with human serum albumin. The phosphorescence of Ir1-HSA was enhanced significantly compared to parent complex Ir1. The long phosphorescence lifetime and high 1O2 quantum yield of Ir1-HSA are highly favourable properties for photodynamic therapy. Ir1-HSA mainly accumulated in the nucleus of living cancer cells and showed remarkable photocytotoxicity against a range of cancer cell lines and tumor spheroids (light IC50; 0.8-5 μM, photo-cytotoxicity index PI = 40-60) while remaining non-toxic to normal cells and normal cell spheroids, even after photo-irradiation. This nucleus-targeting organoiridium-albumin is a strong candidate photosensitizer for anticancer photodynamic therapy.
关键词： Albumin,Organoiridium,Photosensitizer,Photodynamic therapy
更新于2025-09-04 15:30:14
-
Interaction Between Phenanthorline and Proteins: A Fluorescence Spectroscopy-Based Study
摘要： Serum albumin with cardinal physiological functions is the most abundant protein in blood plasma. The concentration of serum albumin is an index of physical health and disease. Spectrophotometry was always used to determinate the concentration of serum albumin. In present study, a novel method for the determination of proteins was established based on the enhanced fluorescence intensity derived from the binding interaction of phenanthorline with proteins in the CH3COOH-CH3COONa buffer at pH 5.98. Underlying the excitation wavelength at 270 nm and the emission wavelength at 366 nm, the enhancement of fluorescence intensity was proportional to the concentration of proteins. The linear range for the calibration graph of human serum albumin was 20-160 μg/mL and the detection limit was 24.12 μg/mL. The recovery was 95.0-105.3 %. The method was sensitive, accurate, required fewer samples and was tolerant of many foreign substances.
关键词： Human serum albumin,Fluorometry,Phenanthorline
更新于2025-09-04 15:30:14