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An opsin 5–dopamine pathway mediates light-dependent vascular development in the eye
摘要： During mouse postnatal eye development, the embryonic hyaloid vascular network regresses from the vitreous as an adaption for high-acuity vision. This process occurs with precisely controlled timing. Here, we show that opsin 5 (OPN5; also known as neuropsin)-dependent retinal light responses regulate vascular development in the postnatal eye. In Opn5-null mice, hyaloid vessels regress precociously. We demonstrate that 380-nm light stimulation via OPN5 and VGAT (the vesicular GABA/glycine transporter) in retinal ganglion cells enhances the activity of inner retinal DAT (also known as SLC6A3; a dopamine reuptake transporter) and thus suppresses vitreal dopamine. In turn, dopamine acts directly on hyaloid vascular endothelial cells to suppress the activity of vascular endothelial growth factor receptor 2 (VEGFR2) and promote hyaloid vessel regression. With OPN5 loss of function, the vitreous dopamine level is elevated and results in premature hyaloid regression. These investigations identify violet light as a developmental timing cue that, via an OPN5–dopamine pathway, regulates optic axis clearance in preparation for visual function.
关键词： Hyaloid regression,Vascular development,Dopamine,VEGFR2,Light-dependent,Eye,Opsin 5,Retinal ganglion cells
更新于2025-11-21 11:20:42
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A facile dopamine-assisted method for the preparation of antibacterial surfaces based on Ag/TiO2 nanoparticles
摘要： Highly effective antibacterial surfaces are crucial to prevent bacterial infections. In this work, we developed a simple method based on Ag/TiO2 nanoparticles via a dopamine-assisted process with long-term antibacterial efficacy, for the preparation of antibacterial glass surfaces. The chemical and morphological features of the prepared surfaces were investigated through field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, X-ray diffraction, and X-ray photoelectron spectrometry. The ultraviolet-visible spectroscopy absorption spectra of the prepared glass samples were measured with a spectrophotometer. The prepared Ag/TiO2 nanoparticle modified surfaces exhibited high activity in the elimination of the Gram-negative Escherichia coli and Gram-positive Bacillus subtilis bacteria under visible light and still maintained good antibacterial properties against E. coli after immersion in phosphate buffered saline solution for 60 days.
关键词： Silver,Dopamine,Titanium dioxide,Glass,Antibacterial property
更新于2025-11-21 11:08:12
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Highly sensitive and selective label-free detection of dopamine in human serum based on nitrogen-doped graphene quantum dots decorated on Au nanoparticles: Mechanistic insights through microscopic and spectroscopic studies
摘要： A rapid, facile and label-free sensing strategy is developed for the detection of dopamine (DA) in the real samples by exploiting nitrogen-doped graphene quantum dots (N-GQDs) decorated on Au nanoparticles (Au@N-GQD). The as-grown Au@N-GQD exhibits strong blue fluorescence at room temperature and the fluorescence intensity is drastically quenched in presence of DA in neutral medium. The mechanistic insight into the DA sensing by Au@N-GQDs is explored here by careful monitoring of the evolution of the interaction of Au NPs and N-GQDs with DA under different conditions through electron microscopic and spectroscopic studies. The highly sensitive and selective detection of DA over a wide range is attributed to the unique core-shell structure formation with Au@N-GQD hybrids. The quenching mechanism involves the ground state complex formation as well as electron transfer from N-GQDs. The presence of Au NPs in Au@N-GQD hybrids accelerates the quenching process (~14 fold higher than bare N-GQDs) by the formation of stable dopamine-o-quinone (DQ) in this present detection scheme. The fluorescence quenching follows the linear Stern-Volmer plot in the range 0-100 μM, establishing its efficacy as a fluorescence-based DA sensor with a limit of detection (LOD) 590 nM, which is ~27 fold lower than the lowest abnormal concentration of DA in serum (16 μM). This sensing scheme is also successively applied to trace DA in Brahmaputra river water sample with LOD 480 nM including its satisfactory recovery (95-112%). Our studies reveal a novel sensing pathway for DA through the core-shell structure formation and it is highly promising for the design of efficient biological and environmental sensor.
关键词： Dopamine,Fluorescence quenching,Nitrogen-doped graphene quantum dots,Colorimetric sensing,Core-shell structure,Gold nanoparticles
更新于2025-11-21 11:01:37
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Multi-layer CeO2-wrapped Ag2S microspheres with enhanced peroxidase-like activity for sensitive detection of dopamine
摘要： A novel core-shell structure Ag2S@CeO2 microspheres were synthesized by growing multi-layer CeO2 onto Ag2S particles. Compared with pure Ag2S, the resultant composite catalyst exhibited highly improved peroxidase-like activity. Influences of pH, temperature, H2O2 concentration and the amount of catalyst on the catalytic activity of Ag2S@CeO2 were investigated. Besides, Ag2S@CeO2 displayed a strong affinity towards H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB). Based on the excellent peroxidase-like activity of Ag2S@CeO2 microspheres, a highly sensitive and selectivity colorimetric method for dopamine detection was developed. The possible catalytic mechanism was also studied using fluorescent probe analysis. It is believed that the efficient biosensor based on the as-prepared Ag2S@CeO2 microspheres can apply for biological analysis and environmental monitoring.
关键词： Core-shell,Ag2S,CeO2,Peroxidase,Dopamine
更新于2025-11-14 17:15:25
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Non-enzymatic sensing of dopamine by localized surface plasmon resonance using carbon dots-functionalized gold nanoparticles
摘要： A highly selective, sensitive, and rapid colorimetric sensor for the determination of dopamine (DA) was developed using the color change of S-doped carbon dots functionalized gold nanoparticles (S-CDs@Au NPs). The base of the method is the formation of a complex between the amine groups of dopamine with carboxylic groups of S-CDs@Au NPs followed by their aggregation with Fe3+ ions which acts as the linkers causing a red shift from 520 to 670 nm in the localized surface plasmon peak of S-CDs@Au NPs. The ratio of absorbance intensity at 670 nm to 520 nm was monitored as the analytical signal for determination of dopamine. The parameters affecting the analytical signal including reaction time, solution pH, the concentration of Au NPs and concentration of Fe3+ were optimized. At optimized conditions, the calibration curve was linear in the concentration range of 0.81-16.80 μM of dopamine. The detection and quantification limits were 0.23 μM and 0.77 μM, respectively. The intra-day and inter-day relative standard deviation (RSDs) at 5.0 μM of DA were 3.9% and 5.6%, respectively (n = 5). The applicability of the method for determination of DA in dopamine ampoule, urine and serum human samples was investigated.
关键词： Carbon dots,Localized surface plasmon resonance,Colorimetric chemical sensor,Dopamine,Gold nanoparticles
更新于2025-11-14 15:18:02
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Ultra-selective fiber optic SPR platform for the sensing of dopamine in synthetic cerebrospinal fluid incorporating permselective nafion membrane and surface imprinted MWCNTs-PPy matrix
摘要： Surface plasmon resonance (SPR) based dopamine sensor is realized using the state-of-art technique of molecular imprinting over an optical fiber substrate. Polypyrrole (PPy) is depicted as an effective polymer for the imprinting of dopamine through a green synthesis approach. Sensitivity of the probe is enhanced by the augmenting effect of surface imprinting of dopamine in polypyrrole over multiwalled carbon nanotubes (MWCNTs). To ensure the permselectivity of the probe towards dopamine molecules, a cation exchange polymer, nafion, is utilized as a membrane over imprinted sites to reduce the interference from anionic analytes like ascorbic acid and uric acid at physiological pH. The probe is characterized for a wide range of dopamine concentration from 0 to 10-5 M in artificial cerebrospinal fluid. Various probe parameters are varied to maximize the sensitivity of the sensor. The sensor possesses 18.9 pM as the limit of detection (LOD) which is lowest of those reported in the literature. The manifestation of sensing probe over an optical fiber along with the improved LOD makes the approach highly advantageous in terms of stability, repeatability, online remote monitoring, fast response, and miniaturization for its in vivo/in vitro applications in clinical sensing of dopamine.
关键词： surface plasmon,dopamine,Optical fiber,polypyrrole,nafion,molecular imprinting,sensor,multiwalled carbon nanotube
更新于2025-10-22 19:40:53
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Electrochemiluminescence sensor based on upconversion nanoparticles and oligoaniline-crosslinked gold nanoparticles imprinting recognition sites for the determination of dopamine
摘要： For the determination of dopamine (DA) in serum samples, a quenching-type electrochemiluminescence sensor was constructed in this study. Upconversion nanoparticles (UCNPs) enhanced by covalent organic frameworks (COFs)-based hybrid and oligoaniline-crosslinked gold nanoparticles (AuNPs) imprinting recognition sites were introduced in electrochemiluminescence (ECL) system at first time. The porous COFs-based hybrid with large specific surface area was modified on the electrode firstly to hold more UCNPs and imprinting recognition sites. AuNPs, here, was employed in developed sensor for two objectives: 1) AuNPs on COFs-based hybrid enabled the hybrid to tunnel the electrons, which helped to improve the ECL intensity; 2) AuNPs-based thioaniline units (PATP@AuNPs) electropolymerized on the electrode in the presence of template to form oligoaniline-crosslinked AuNPs matrix. Then the exclusion of template from matrix yielded molecularly three-dimensional imprinted contours with conductivity, conducive to specific recognition and further amplify the ECL. The double recognition mode in this work involves the recognition effect of imprinted contours and quenching effect of o-benzoquinone species. The quantum chemical calculation was performed to analyzing the possible recognition and binding mechanisms of molecularly three-dimensional imprinted contours. The results showed imprinted contours could bind the target by complementary spatial cavities and weak interactions. The proposed approach yields a wide detection range (10-14-10-6 M), low limit of detection (LOD=2×10-15 M) and acceptable recoveries (93.25%-112.97%) in rat serum sample, demonstrating that the developed method holds great promise to be applied to DA detection in practical samples.
关键词： Electroconductibility molecular imprinting polymer,Covalent organic frameworks,Oligoaniline-crosslinked gold nanoparticles,Dopamine,Electrochemiluminescence
更新于2025-09-23 15:23:52
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Label-free fluorescent discrimination and detection of epinephrine and dopamine based on bioinspired in situ copolymers and excitation wavelength switch
摘要： A simple and label-free fluorescence turn-on method is proposed for the discrimination and detection of epinephrine (Ep) and dopamine (DA) via polyethyleneimine (PEI)-initiated in situ copolymerization and excitation wavelength switch. The PEI solution in the presence of Ep, DA and the mixture of Ep and DA are denoted as PEp-PEI, PDA-PEI and MEptDA, respectively. In this study, PEI aqueous solution medium initiates the auto-oxidization of Ep and DA and the bioinspired copolymerization. These resultant copolymers emit yellow-green fluorescence color with a fluorescence emission maximum at 515 nm. Interestingly, these fluorescent copolymers exhibit distinct different excitation spectra, although Ep and DA are structurally very similar. PDA-PEI exhibits only one excitation peak at 385 nm, and PEp-PEI shows dual-excitation mode with two significant excitation peaks at 328 nm and 405 nm, respectively. MEptDA also shows dual-excitation mode with two excitation peaks at 330 nm and 395 nm, respectively. Thus, individual Ep, DA, and their mixture can be discriminated based on the different excitation spectral shapes and peak locations of PEp-PEI, PDA-PEI and MEptDA. Furthermore, the quantitative analysis of Ep and DA in mixture can also be achieved by switching excitation wavelength between 330 and 395 nm and monitoring the fluorescence emission intensity of MEptDA at 515 nm. The fluorescence intensity of MEptDA only related to the concentration of Ep when excited at 330 nm. Moreover, the concentration of DA can also be calculated by subtracting the fluorescence intensity of PEp-PEI from the total fluorescence intensity when excited at 395 nm. The resultant method has been used to simultaneously detect Ep and DA in human urine samples. The proposed fluorescence system is facile, eco-friendly, low-cost, and time-saving, and also provides a new and simple path for discriminating analogues.
关键词： Epinephrine,Fluorescence turn-on,Polyethyleneimine,Dopamine,Simultaneous discrimination and detection
更新于2025-09-23 15:23:52
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Simultaneous Cr(VI) removal and bisphenol A degradation in a solar-driven photocatalytic fuel cell with dopamine modified carbon felt cathode
摘要： In this work, a carbon felt cathode modified by dopamine (DPA/CF) was explored to enhance the cathodic reduction of Cr(VI) in a two chambers photoelectrochemical system, which was driven by solar light irradiation using BiVO4 photoanode. In the anode chamber, the bisphenol A (BPA) decomposition can be significantly improved by increasing pH to 8. The electron-hole pairs photogenerated on the surface of BiVO4 were efficiently separated by the application of the DPA/CF cathode. At the optimal conditions, 86% of low-concentration BPA was removed within 60 min. In the cathodic chamber, 80% of Cr(VI) was removed at pH of 4. Based on the XPS and electrochemical analyses, it was proposed that the positively-charged groups on the DPA/CF cathode led to the multilayer adsorption of Cr(VI) anions, which enhanced the reduction of Cr(VI) with the electrons generated on the BiVO4. On the other hand, the CeO groups on the DPA/CF electrode also played an important role as electron transfer mediator for Cr(VI) reduction. The prepared DPA/CF cathode associated with BiVO4 photoanode could be a potential application for efficient removal of Cr(VI) and organic pollutants under solar light irritation.
关键词： BiVO4 photoanode,Carbon felt cathode,Dopamine,Cr(VI),Solar photocatalysis,BPA
更新于2025-09-23 15:23:52
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Surface Plasmon Resonance Based Highly Selective Fiber Optic Dopamine Sensor Fabricated Using Molecular Imprinted GNP/SnO <sub/>2</sub> Nanocomposite
摘要： Fabrication and characterization of a highly selective fiber optic surface plasmon resonance-based dopamine sensor using molecular imprinted graphene nanoplatelets/tin oxide (SnO2) nanocomposite have been reported. The synthesis of sensing layer has been carried out using a series of optimizations and morphological studies. The effectiveness of the sensing layer over other possible probe designs has been proved by performing control experiments for a dopamine concentration range covering the suggested level of dopamine for human being. The limit of detection (LOD) of the sensor evaluated is 0.031 μM, which is lower than the LOD values of various dopamine sensors fabricated using different methods. The specificity of the sensor for dopamine has been confirmed by performing experiments using various interferands while the stability and reusability of the sensor probe have been checked by performing experiments repeatedly for a long period of time. Apart from high sensitivity, low LOD, and fast response, the sensor can be used for remote sensing and online monitoring of dopamine.
关键词： surface plasmon resonance,SnO2 nanoparticles,optical fiber sensor,GNP/SnO2 nanocomposite,graphene,Dopamine,molecular imprinting
更新于2025-09-23 15:23:52