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Optical responses of BSA protein under re-entrant condensation in presence of trivalent ions
摘要： Fluorescence behavior of globular protein like BSA is studied under the re-entrant condensation in the presence of trivalent salts like YCl3 and LaCl3. BSA shows a re-entrant behaviour in solution where a specific turbid phase is formed between the two critical concentrations of the trivalent salts. Optical behaviours of proteins are explored by UV-Vis, photoluminescence and time resolved photoluminescence (TRPL) spectroscopy, whereas hydrodynamic size is obtained from the dynamic light scattering (DLS) technique. BSA shows maximum emission intensity at ≈ 338 nm for an excitation at 278 nm, however, the value of the peak intensity of emission gradually increases with the increase in salt concentration and becomes maximum at the turbid phase but for higher salt concentration as the re-dissolution takes place the emission intensity again decreases. TRPL study suggests that the decay time of BSA under re-entrant condensation is correlated with the salt concentration, whereas DLS study shows that the hydrodynamic size gradually increases up to a certain salt concentration where turbid phase is formed and then again decreases for higher salt concentrations. The variation of emission intensity of BSA nearly follows the modification of diffusion coefficient or hydrodynamic size and the phase transition behaviours.
关键词： UV-Vis spectroscopy,Bovine serum albumin,Tri-valent ions,Re-entrant condensation,Fluorescence spectroscopy
更新于2025-09-23 15:23:52
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Quantification of Glucose via in situ Growth of Cu2O/Ag Nanoparticles
摘要： The monitoring of glucose levels in blood is extremely important for the effective control of diabetes. Nanomaterial-based approaches for the quantification of glucose typically require two steps: material preparation and the actual glucose measurement. Herein, we report a single-step method that combines these functions via the in situ growth of Cu2O/Ag nanoparticles (NPs). Mechanistically, we use glucose itself to reduce Cu2+ and Ag+ ions that are stabilized with 3-mercaptopropionic acid (3-MPA) and bovine serum albumin (BSA) under alkaline conditions to form Cu2O/Ag NPs and produce a color change in solution due to plasmonic resonance at 400 nm, which can be related back to the concentration of glucose. We study several factors in this reaction, including the molar ratios of the metal ions and 3-MPA, the reaction time, and the temperature to control the synthesis of the Cu2O/Ag NPs and thus their sensitivity toward glucose. Introducing BSA into the system is a key factor for the quantification of glucose in blood without pretreatment, improving the probe’s limit of detection and reducing the sample volumes to 1 μL. This colorimetric assay based on Cu2O/Ag NPs exhibits excellent sensitivity and specificity toward glucose, and a linear relationship with glucose concentrations ranging from 15 to 300 μM and a limit of detection of 9.2 μM. As proof of concept, we demonstrated that the Cu2O/Ag NP probes could successfully detect glucose in two representative blood samples by neglecting interferences from various common species, demonstrating the potential of this technique in point-of-care analysis.
关键词： plasmonic resonance,3-mercaptopropionic acid,bovine serum albumin,silver nanoparticles,glucose quantification,Cu2O
更新于2025-09-23 15:23:52
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Squaraine dyes: interaction with bovine serum albumin to investigate supramolecular adducts with aggregation-induced emission (AIE) properties
摘要： Bovine Serum Albumin (BSA)–squaraine supramolecular adducts with aggregation-induced emission (AIE) properties were prepared and characterized by spectroscopic methods. While squaraine dyes showed very low fluorescence quantum yield in water, a great enhancement in the fluorescence of the aggregated BSA adducts was achieved due to the abnormal aggregation-induced emission properties of squaraines. The adducts formation was studied from a kinetic point of view showing unexpected structure-properties relationships.
关键词： squaraines,supramolecular adducts,Bovine Serum Albumin (BSA),kinetics,Aggregation-induced emission (AIE)
更新于2025-09-23 15:22:29
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Potassium triiodide-quenched gold nanocluster as a fluorescent turn-on probe for sensing cysteine/homocysteine in human serum
摘要： A fluorescent sensing platform using KI3-quenched bovine serum albumin stabilized gold nanoclusters has been designed and used as a fluorescent probe for the turn-on detection of homocysteine/cysteine (Cys/Hcy). The fluorescence of gold nanoclusters was quenched by iodine. The fluorescence of quenched gold nanoclusters was effectively switched on by Cys/Hcy devoid of the interference of glutathione. The transmission electron microscopy image, X-ray photoelectron spectroscopy analysis, time-correlated single photon counting analysis, and dynamic light scattering data confirmed the aggregation-induced quenching of fluorescence of gold nanoclusters by iodine. The turn-on response of Cys/Hcy shows two linear ranges from 0.0057 to 5 μM and from 8 to 25 μM, with a limit of detection of 9 nM for cysteine and 12 nM for homocysteine. Real samples were analyzed to monitor Cys/Hcy added to human serum. The fluorescence turn-on response of the probe on a paper strip in the presence of Cys/Hcy was studied.
关键词： Cysteine,Fluorescence turn on,Gold nanocluster,Bovine serum albumin,Iodine,Homocysteine
更新于2025-09-23 15:22:29
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Encapsulation of zinc phthalocyanine into bovine serum albumin aggregates
摘要： Artificial hybridization of molecules with proteins is beneficial for biomedical applications. Herein, we describe a novel method for encapsulation of zinc phthalocyanine (ZnPc) aggregates into bovine serum albumin (BSA) aggregates, but not monomeric BSA. This property is potentially useful for not only photodynamic or photothermal therapy but also development of a novel delivery system for hydrophobic drug molecules.
关键词： Gel-filtration chromatography,Photosensitizer,Aggregation,Bovine serum albumin,Phthalocyanine,Photodynamic therapy
更新于2025-09-23 15:22:29
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Synthesis, Anticonvulsant and Binding Interaction Study of Novel Piperamides with Bovine Serum Albumin by Fluorescence Spectroscopy
摘要： A series of piperamides (PA) 8a-j were designed, synthesized and evaluated for their antimicrobial and anticonvulsant activity. Compounds 8a and 8h showed considerable antibacterial activity against B. subtilis with minimum inhibitory concentration (MIC) of 8 and 10 μg/mL, respectively. Compounds 8a and 8h showed advanced anticonvulsant activity as well as lower neurotoxicity than the reference drugs. The interaction between bovine serum albumin (BSA) and PA was investigated using fluorescence quenching and UV-vis absorption spectroscopy. Results showed that PA could strongly quench the intrinsic fluorescence of BSA through a static quenching procedure. The binding constant and number of binding sites of PA with BSA were obtained. The binding distance was calculated based on Forster non-radiative energy transfer theory.
关键词： Anticonvulsant,bovine serum albumin,fluorescence quenching,piperamide
更新于2025-09-23 15:22:29
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Alkyne Functionalization of a Photoactivated Ruthenium Polypyridyl Complex for Click-Enabled Serum Albumin Interaction Studies
摘要： Studying metal-protein interactions is key for understanding the fate of metallodrugs in biological systems. When a metal complex is not emissive and too weakly bound for mass spectrometry analysis, however, it may become challenging to study such interactions. In this work a synthetic procedure was developed for the alkyne functionalization of a photolabile ruthenium polypyridyl complex, [Ru(tpy)(bpy)(Hmte)](PF6)2, where tpy = 2,2′:6′,2′′-terpyridine, bpy = 2,2′-bipyridine, and Hmte = 2-(methylthio)ethanol. In the functionalized complex [Ru(HCC-tpy)(bpy)(Hmte)](PF6)2, where HCC-tpy = 4′-ethynyl-2,2′:6′,2′′-terpyridine, the alkyne group can be used for bioorthogonal ligation to an azide-labeled fluorophore using copper-catalyzed “click” chemistry. We developed a gel-based click chemistry method to study the interaction between this ruthenium complex and bovine serum albumin (BSA). Our results demonstrate that visualization of the interaction between the metal complex and the protein is possible, even when this interaction is too weak to be studied by conventional means such as UV?vis spectroscopy or ESI mass spectrometry. In addition, the weak metal complex-protein interaction is controlled by visible light irradiation, i.e., the complex and the protein do not interact in the dark, but they do interact via weak van der Waals interactions after light activation of the complex, which triggers photosubstitution of the Hmte ligand.
关键词： ruthenium polypyridyl complex,click chemistry,bovine serum albumin,photoactivation,alkyne functionalization,metal-protein interactions
更新于2025-09-23 15:21:01
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[Methods in Molecular Biology] Microfluidic Electrophoresis Volume 1906 (Methods and Protocols) || Paper-Based Electrophoresis Microchip as a Powerful Tool for Bioanalytical Applications
摘要： This chapter describes the development of paper-based microchip electrophoresis (pME) devices for the separation of clinically relevant compounds. pME were fabricated by laser cut and thermal lamination process using polyester pouches. In addition, hand-drawn pencil electrodes were integrated to the device to perform capacitively coupled contactless conductivity detection (C4D). Finished device costs less than US$ 0.10 and did not require either sophisticated instrumentation or clean room facilities. Furthermore, pME is lightweight, easy to handle, ?exible, and robust. pME-C4D device revealed an excellent capacity to separate BSA and creatinine in less than 150 s with baseline resolution. The device proposed in this chapter has proven to be a good alternative as a platform for the diagnosis of diseases from renal disorders such as diabetes mellitus and heart disease.
关键词： Biomolecules,Paper electrophoresis,Kidney failure,Pencil electrodes,Bovine serum albumin,Creatinine,Clinical diagnosis,Contactless conductivity detection
更新于2025-09-23 15:21:01
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[ACM Press the 2017 2nd International Conference - Wuhan, China (2017.11.07-2017.11.09)] Proceedings of the 2017 2nd International Conference on Communication and Information Systems - ICCIS 2017 - Effect of Concentration on Surface Acoustic Wave Velocity in A Rayleigh-type Biosensor
摘要： To predict the propagation velocity of different concentrations of bovine serum albumin (BSA) in a Rayleigh-type biosensor, we derived a new calculation method for a Rayleigh surface acoustic wave (SAW) device. The method can calculate propagation velocities of leaky Rayleigh waves and Rayleigh waves when liquid is placed in the groove of a Rayleigh-type SAW device. Different concentration of BSA proteins were used to evaluate the effect of these concentrations. In this study, we used different concentrations of BSA and a Rayleigh-type SAW device consisted of grooves of 0.25 mm width and 0.26 mm height and grooves of 0.40 mm width and 0.25 mm height, quartz as the substrate and interdigital transducers (IDT) with a 25.00 mm distance. The frequency of the Rayleigh-type SAW device was set to 157.6 MHz. Our data suggests that the propagation velocity of SAWs depends mainly upon BSA protein concentration and the size of groove. At the same concentration of BSA, the propagation acoustic wave velocity of BSA depends on the size of groove. The results showed the 0.40 mm width-0.25 mm height groove was more suitable than the 0.25 mm width-0.26 mm height groove for studying the propagation velocity of wave with liquid in a Rayleigh-type SAW device. With the propagation velocity decreased when the concentration of BSA protein increased.
关键词： Surface acoustic wave (SAW),Rayleigh-type SAW device,Leaky Rayleigh wave,Bovine serum albumin (BSA),Rayleigh wave
更新于2025-09-23 15:21:01
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Water Soluble Fluorescent Graphene Nanodots
摘要： Water soluble fluorescent graphene nanodots (GND) have been successfully prepared through a bottom up approach from brominated pyrene via alkaline hydrothermal condensation. FT-IR, UV-Vis, Raman, XRD, AFM, and TEM studies have shown the formation of (cid:2)OH group rich nano-dots having graphene features with an approximate size of 90 nm. Steady state and 3D fluorescence studies have shown efficient fluorescence emission with maximum at 540 nm upon excitation at 450 nm in pH (cid:3) 7. Plasmid deoxyribonucleic acid (plasmid DNA) and bovine serum albumin (BSA) have shown their interaction with GND, which was studied via fluorescence quenching of GND and BSA, respectively. Selective quenching of the Fo¨ rster resonance energy transfer (FRET) of BSA-GND conjugate via ascorbic acid (AA) has been used to construct a calibration curve for AA estimation with a linear range and limit of detection of 34.00–112.00 mmole/L respectively. GND has also shown and 31.343 mmole/L, turn offchemosensing towards concentration-dependent heavy metals like Pb2 +, Cu2 +, Hg2 + and Zn2 +. In-vitromulti-color fluorescence imaging has been observed in GND-labelled HeLa (human cervical cancer) and NIH-3T3 (mouse embryonic fibroblast) cell lines with better uptake by HeLa cells. GND also has shown very high viability for both the cell lines up to the tested concentration of 300 mg/mL.
关键词： fluorescence,graphene nanodots,F?rster resonance energy transfer,brominated pyrene,bovine serum albumin
更新于2025-09-23 15:21:01