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Studies on the Interaction of Cefepime Hydrochloride with Bovine Serum Albumin by Fluorescence, Synchronous Fluorescence, Three-Dimensional Fluorescence and Circular Dichroism
摘要： The investigation on the binding mode between drug and protein is extremely important to understand biopharmaceutics, pharmacokinetics and toxicity of the drug as well as the relationship of structure and function of the protein. It is well proved that biological activity is a function of the chemical structure or structural properties. There is a study on the interaction of cefepime hydrochloride with serum albumin using in-silico molecular docking. But up to date, there is hardly any interaction investigation of cefepime hydrochloride with serum albumin utilizing by fluorescence, synchronous fluorescence, three-dimensional fluorescence and circular dichroism. In this study, the interaction of cefepime hydrochloride with bovine serum albumin in aqueous solution has been investigated by molecular spectroscopy under different pH conditions. The quenching rate constant and binding constant calculated at pH 7.4 indicated the static quenching mechanism and medium binding force. The effect of cefepime hydrochloride on the conformation of bovine serum albumin was analyzed using fluorescence, synchronous fluorescence, three-dimensional fluorescence and circular dichroism. In addition, influence of pH on the binding of cefepime hydrochloride to bovine serum albumin was investigated and the binding ability of the drug to bovine serum albumin deceased under other pH conditions (pH 1.9, 3.5, and 9.0) as compared with that at pH 7.4. As compared with the binding ability of cefepime hydrochloride to native bovine serum albumin that of cefepime hydrochloride to denatured bovine serum albumin deceases dramatically. Furthermore, the effect of metal ions on the binding constant of cefepime hydrochloride with bovine serum albumin was investigated.
关键词： Circular dichroism,Fluorescence quenching,Bovine serum albumin,Three-dimensional fluorescence,Cefepime hydrochloride
更新于2025-09-23 15:21:01
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Protein Content Sensor based on Plastic Optical Fiber
摘要： Plastic optical fiber (POF) content protein sensor has been developed. This sensor is made with a gamma and spiral configuration, with a cladding peel length of 5 cm. POF sensor is dipped into the container containing Bovine Serum Albumin (BSA) solution with different concentrations of 0.1-1 mg/ml. Both ends of the sensor are connected by Light Emiting Diode (LED) and Phototransistor. The LED light will propagate through the POF and it is received by the phototransistor. Light that propagates will be interfenced due to increasing of protein concentration around the sensor, so that the output voltage will be affected. The output voltage will be forwarded to Arduino Uno and read by the computer. The best results were obtained in a spiral configuration with 3 bending with a sensitivity of 0.007 Vml/mg and a resolution of 0.142 mg/ml. This method has advantages that are easy fabrication, simple measurement process, and low cost.
关键词： protein sensor,Plastic optical fiber,Phototransistor,Arduino Uno,Bovine Serum Albumin,LED
更新于2025-09-23 15:19:57
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Ultrasensitive detection of nonlabelled bovine serum albumin using photothermal optical phase shift detection with UV excitation
摘要： Ultrasensitive detection of nonlabelled bovine serum albumin is performed in micro/nano?uidic chips using a photothermal optical phase shift (POPS) detection system. Currently, micro- and nano?uidics allow the analysis of various single cells, and their targets of interest are shifting from nucleic acids to proteins. Previously, our group developed photothermal detection techniques for the sensitive detection of non?uorescent molecules. For example, we developed a thermal lens microscope (TLM) with ultrahigh sensitivity at the single-molecule level and a POPS detector that is applicable to nanochannels smaller than the wavelength of light. The POPS detector also realized the detection of nonlabelled proteins in nanochannels, although its detection sensitivity is less than that of the TLM in microchannels due to insu?cient background light reduction. To overcome this problem, we developed a new POPS detector using relay optics for further reduction of the background light. In addition, heat transfer from the sample solution to the nanochannel wall was thoroughly investigated to achieve ultrahigh sensitivity. The limit of detection (LOD) obtained with the new POPS detector is 30 molecules in 1.0 fL. Considering this LOD, the performance of the new POPS detector is comparable with that of the TLM. Owing to the applicability of the POPS detector for sensitive detection even in nanochannels or single-μm channels, which cannot be realized with the TLM, combinations of the POPS detector and separation techniques employing unique nanochannel properties will contribute to advances in single-cell proteomics in the future.
关键词： Ultrasensitive detection,micro/nano?uidic chips,single-cell proteomics,photothermal optical phase shift,bovine serum albumin
更新于2025-09-23 15:19:57
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Protein-based microsphere biolasers fabricated by dehydration
摘要： Biolasers made of biological materials have attracted considerable research attention due to their biocompatibility and biodegradability, and have the potential for biosensing and biointegration. However, the current fabrication methods of biolasers suffer from several limitations, such as complicated processing, time-consuming and environmentally unfriendly nature. In this study, a novel approach with green processes for fabricating solid-state microsphere biolasers has been demonstrated. By dehydration via a modified Microglassificationt technology, dye-doped bovine serum albumin (BSA) droplets could be quickly (less than 10 minutes) and easily changed into solid microspheres with diameters ranging from 10 mm to 150 mm. The size of the microspheres could be effectively controlled by changing either the concentration of the BSA solution or the diameter of the initial droplets. The fabricated microspheres could act as efficient microlasers under an optical pulse excitation. A lasing threshold of 7.8 mJ mm?2 and a quality (Q) factor of about 1700 to 3100 were obtained. The size dependence of lasing characteristics was investigated, and the results showed a good agreement with whispering gallery mode (WGM) theory. Our findings contribute an effective technique for the fabrication of high-Q factor microlasers that may be potential for applications in biological and chemical sensors.
关键词： microspheres,dehydration,whispering gallery mode,bovine serum albumin,biolasers
更新于2025-09-16 10:30:52
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Liquid crystal-based capacitive, electro-optical and dielectric biosensors for protein quantitation
摘要： The electrical, electro-optical and dielectric properties of liquid crystals (LCs) are routinely manipulated in liquid-crystal display (LCD) devices, but their potential application in the development of biosensors is still in a nascent stage. In this review, utilising the electrical properties, electro-optical effect and dielectric anisotropy in LCs, we provide insights into several possible modes of label-free biodetection and describe how capacitance, electro-optical and dielectric measurements of various LCs assist in quantitative analysis of biomolecules. It is concluded that the electrically induced biosensing techniques proposed here provides new incentives for researchers to study the interaction between LCs and biomolecules and to resolve technical hurdles facing the development of LC-based biosensors.
关键词： bovine serum albumin,biosensing,dielectric spectroscopy,Electro-optical measurement,protein,capacitance
更新于2025-09-16 10:30:52
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Fluorescence ON-OFF switching, Boolean logic gates like behavior of carbon quantum dots and highly sensitive bovine serum albumin sensing
摘要： We demonstrate ?uorescence “ON-OFF” switching and photonic logic gates based on ?uorescence response of carbon quantum dots (CQDs) in the presence of graphene oxide (GO), reduced graphene oxide (RGO), and bovine serum albumin (BSA). We study the excited state electron and energy transfer interactions among the carbon based materials in detail through steady state ?uorescence (SSF) and time resolved ?uorescence (TRF) spectroscopy. CQDs function as donor; GO and RGO function as acceptors. SSF results show the ?uorescence “turn-OFF” behavior of CQDs in the presence of GO and RGO, and the reason is explained through Stern-Volmer plots. TRF results reveal a decrease in the decay time components of CQDs in the presence of GO and RGO. The gradual recovery of quenched ?uorescence of CQDs is observed by the addition of BSA at nanomolar concentrations which shows the highly sensitive “turn-ON” BSA sensing. Single input and two inputs photonic logic gates are implemented based on the ?uorescence response of CQDs in the presence of GO, RGO, and BSA in di?erent input combinations. The NOT, PASS1, NOR, and IMPLICATION gates like behavior of CQDs is demonstrated.
关键词： bovine serum albumin sensing,fluorescence ON-OFF switching,carbon quantum dots,Boolean logic gates
更新于2025-09-11 14:15:04
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Dynamic intermolecular interactions control adsorption from mixtures of natural organic matter and protein onto titanium dioxide nanoparticles
摘要： Engineered nanoparticles (NPs) will obtain macromolecular coatings in environmental systems, changing their subsequent interactions. The matrix complexity inherent in natural waters and wastewaters greatly complicates prediction of the corona formation. Here, we investigate corona formation on titanium dioxide (TiO2) NPs from mixtures of natural organic matter (NOM) and a protein, bovine serum albumin (BSA), to thoroughly probe the role of mixture interactions in the adsorption process. Fundamentally different coronas were observed under different NP exposure conditions and time scales. In mixtures of NOM and protein, the corona composition was kinetically determined, and the species initially co-adsorbed but were ultimately limited to monolayers. On the contrary, sequential exposure of the NPs to pure solutions of NOM and protein resulted in extensive multilayer formation. The intermolecular complexation between NOM and BSA in solution and at the NP surface was the key mechanism controlling these distinctive adsorption behaviors, as determined by size exclusion chromatography (SEC) and in situ attenuated total reflectance – Fourier transform infrared (ATR-FTIR) spectroscopy. Overall, this study demonstrates that dynamic intermolecular interactions and the history of the NP surface must be considered together to predict corona formation on NPs in complex environmental media.
关键词： corona formation,adsorption,bovine serum albumin,Engineered nanoparticles,titanium dioxide nanoparticles,natural organic matter,intermolecular interactions
更新于2025-09-11 14:15:04
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Luminophore Formation in Various Conformations of Bovine Serum Albumin by Binding of Gold(III)
摘要： The purpose of the presented protocols is to study the process of Au(III) binding to BSA, yielding conformation change-induced red fluorescence (λem = 640 nm) of BSA-Au(III) complexes. The method adjusts the pH to show that the emergence of the red fluorescence is correlated with the pH-induced equilibrium transitions of the BSA conformations. Red fluorescent BSA-Au(III) complexes can only be formed with an adjustment of pH at or above 9.7, which corresponds to the "A-form" conformation of BSA. The protocol to adjust the BSA to Au molar ratio and to monitor the time-course of the process of Au(III) binding is described. The minimum number of Au(III) per BSA, to produce the red fluorescence, is less than seven. We describe the protocol in steps to illustrate the presence of multiple Au(III) binding sites in BSA. First, by adding copper (Cu(II)) or nickel (Ni(II)) cations followed by Au(III), this method reveals a binding site for Au(III) that is not the red fluorophore. Second, by modifying BSA by thiol capping agents, another nonfluorophore-forming Au(III) binding site is revealed. Third, changing the BSA conformation by cleaving and capping of the disulfide bonds, the possible Au(III) binding site(s) are illustrated. The protocol described, to control the BSA conformations and Au(III) binding, can be generally applied to study the interactions of other proteins and metal cations.
关键词： gold,fluorescence,Chemistry,Synthesis,conformation,Issue 138,bovine serum albumin,BSA,Au,pH
更新于2025-09-10 09:29:36
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Lectins at Interfaces—An Atomic Force Microscopy and Multi-Parameter-Surface Plasmon Resonance Study
摘要： Lectins are a diverse class of carbohydrate binding proteins with pivotal roles in cell communication and signaling in many (patho)physiologic processes in the human body, making them promising targets in drug development, for instance, in cancer or infectious diseases. Other applications of lectins employ their ability to recognize specific glycan epitopes in biosensors and glycan microarrays. While a lot of research has focused on lectin interaction with specific carbohydrates, the interaction potential of lectins with different types of surfaces has not been addressed extensively. Here, we screen the interaction of two specific plant lectins, Concanavalin A and Ulex Europaeus Agglutinin-I with different nanoscopic thin films. As a control, the same experiments were performed with Bovine Serum Albumin, a widely used marker for non-specific protein adsorption. In order to test the preferred type of interaction during adsorption, hydrophobic, hydrophilic and charged polymer films were explored, such as polystyrene, cellulose, N,-N,-N-trimethylchitosan chloride and gold, and characterized in terms of wettability, surface free energy, zeta potential and morphology. Atomic force microscopy images of surfaces after protein adsorption correlated very well with the observed mass of adsorbed protein. Surface plasmon resonance spectroscopy studies revealed low adsorbed amounts and slow kinetics for all of the investigated proteins for hydrophilic surfaces, making those resistant to non-specific interactions. As a consequence, they may serve as favorable supports for biosensors, since the use of blocking agents is not necessary.
关键词： lectin,gold,adsorption,bovine serum albumin,polystyrene,surface plasmon resonance spectroscopy,cellulose thin film
更新于2025-09-10 09:29:36
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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