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Construction of liquid crystal-based sensing platform for sensitive and selective detection of L-phenylalanine based on alkaline phosphatase
摘要： The detection of L-phenylalanine (L-Phe) has become one of most pressing issues concerning diagnosis and treatment of phenylketonuria in neonates, yet a simple and robust methodology has yet to be developed. Here the application of novel liquid crystals (LCs) sensing platform for sensitive, selective, and label-free detection of L-Phe was reported at the first time. We devised a strategy to fabricate the sodium monododecyl phosphate (SMP) decorated LC sensing platform with the appearance of dark. Then, a dark to bright (D-B) optical images alteration of LCs was observed after transferring alkaline phosphatase (ALP) to the interface, owing to cleavage of SMP induced by ALP. LCs remained dark images after the SMP-decorated interface in contact with the pre-incubated ALP and L-Phe. Such optical appearance resulted from the inhibition of ALP by L-Phe, which was further verified by the isothermal titration calorimetry (ITC). The strategy was applied to sensing L-Phe, which have been proven to allow for sensitively and selectively differentiation of L-Phe from interfering compounds with similar aromatic groups, as well as seven other essential amino acids. More importantly, the detection limit of L-Phe reached 1 pg/mL in urine samples, further demonstrated its value in the practical applications. Results obtained in this study clearly demonstrated the superiority of LCs towards the L-Phe detection, which can pave a way for the development of high performance and robust probes for L-Phe detection in clinical applications.
关键词： Sensing platform,Alkaline phosphatase,Surfactant,Liquid crystal,Inhibition,L-phenylalanine
更新于2025-09-23 15:23:52
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Switchable fluorescence immunoassay using gold nanoclusters anchored cobalt oxyhydroxide composite for sensitive detection of imidacloprid
摘要： The fabrication of a convenient fluorescence-based immunoassay (FIA) for specific antigen attract increasing concern but remains a considerable challenge, especially the laborious synthesis of nanomaterials-antibody conjugates. Herein, we circumvent this drawback by introducing a specific fluorescence signal response procedure to commercially available alkaline phosphatase (ALP)-labeled conventional immunoassay for imidacloprid detection. In this FIA protocol, gold nanoclusters (AuNCs) can anchor on the surface of two-dimensional cobalt oxyhydroxide (CoOOH) nanoflakes to form nanocomposite, resulting in remarkable decrease of fluorescence intensity. The quenching effects can be effectively reversed by introducing ascorbic acid that can trigger the decomposition of CoOOH nanoflakes. Notably, the corresponding fluorescence response induced by ascorbic acid was related to ALP activities labeled on antibody. After competitive immunoreaction, the ALP-labeled antibodies were bounded to immobilized antigen, which can regulate the fluorescence change. Utilizing fluorescence switching of system, the 50% inhibition concentration (IC50) value of FIA toward imidacloprid was obtained at 1.3 ng mL?1 which was 60-fold-of-magnitude more sensitive than that of conventional ELISA (86.4 ng mL?1). This FIA protocol not only develops new prospects for pesticide detection, but also opens up potent strategy of fluorogenic immunoassay.
关键词： Immunoassay,Composite,Alkaline phosphatase,Fluorescence,Imidacloprid
更新于2025-09-23 15:22:29
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Enhancement of osteoblast activity on nanostructured NiTi/hydroxyapatite coatings on additive manufactured NiTi metal implants by nanosecond pulsed laser sintering
摘要： Background: The osteoinductive behaviors of nitinol (NiTi)-based metal implants for bone regeneration are largely dependent on their surface composition and topology. Continuous-mode laser sintering often results in complete melting of the materials and aggregation of particles, which lack control of heat transfer, as well as microstructural changes during sintering of the nanocomposite materials. Methods: In the current study, in situ direct laser deposition was used to additively manufacture three-dimensional NiTi structures from Ni and Ti powders. The mechanical property of NiTi has been shown to be similar to bone. Nanosecond pulsed laser sintering process was then utilized to generate a nanoporous composite surface with NiTi alloy and hydroxyapatite (HA) by ultrafast laser heating and cooling of Ni, Ti, and HA nanoparticles mixtures precoated on the 3D NiTi substrates; HA was added in order to improve the biocompatibility of the alloy. We then studied the underlying mechanism in the formation of NiTi/HA nanocomposite, and the synergistic effect of the sintered HA component and the nanoporous topology of the composite coating. In addition, we examined the activity of bone-forming osteoblasts on the NiTi/HA surfaces. For this, osteoblast cell morphology and various biomarkers were examined to evaluate cellular activity and function. Results: We found that the nanoscale porosity delivered by nanosecond pulsed laser sintering and the HA component positively contributed to osteoblast differentiation, as indicated by an increase in the expression of collagen and alkaline phosphatase, both of which are necessary for osteoblast mineralization. In addition, we observed topological complexities which appeared to boost the activity of osteoblasts, including an increase in actin cytoskeletal structures and adhesion structures. Conclusion: These findings demonstrate that the pulsed laser sintering method is an effective tool to generate biocompatible coatings in complex alloy-composite material systems with desired composition and topology. Our findings also provide a better understanding of the osteoinductive behavior of the sintered nanocomposite coatings for use in orthopedic and bone regeneration applications.
关键词： metal implants,pulsed laser coating,biocompatibility,differentiation,bone regeneration,alkaline phosphatase,osteoinductive behavior
更新于2025-09-23 15:22:29
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A Strategy for In-Situ Imaging of Cellular Alkaline Phosphatase Activity Using Gold Nanoflower Probe and Localized Surface Plasmon Resonance Technique
摘要： In this work, a simple and ultrasensitive localized surface plasmon resonance (LSPR) method that use Au nanoflowers (AuNFs) as probe was designed for in-situ monitoring of alkaline phosphatase (ALP) activity. The AuNFs was fabricated by hydrogen tetrechloroaurate-induced oxidative disruption of polydopamine-coated Au nanoparticles (AuNPs) and subsequently growth of Au nanopetals on AuNPs. The as-prepared AuNFs showed a much higher LSPR capability and stronger scattering color change than AuNPs. The strategy for in-situ cellular ALP activity detection relied on the deposition of Ag on AuNFs surface, which changed the morphology of AuNFs and led to a tremendous LSPR response and scattering color change. The deposition of Ag shell on AuNFs was related to ALP activity, where ALP catalyzed the hydrolysis of L-ascorbic acid 2-phosphate sesquimagnesium salt hydrate to form L-ascorbic acid (AA), then AA reduced Ag+ to Ag and deposited onto AuNFs. With this concept, the ALP activity could be monitored with a detection limit of 0.03 μU L-1. Meanwhile, the ALP activity of single HepG2 cells and HEK 293 cells was tracked with proposed approach, which indicated the trace expression level of ALP in HEK 293T cell and overexpressed level of ALP in HepG2 cells. After treated with drugs, the cellular ALP activity of HepG2 cells was decreased with the treating time and dose increasing. Therefore, the proposed strategy could be used for tracking the cellular ALP activity, which paved a new avenue for cell studies, and hold great potential for discovering novel ALP-based drugs applications.
关键词： cellular activity,alkaline phosphatase,localized surface plasmon resonance,in-situ imaging,gold nanoflowers
更新于2025-09-23 15:21:21
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Plasmonic Enhanced Gold Nanoclusters-Based Photoelectrochemical Biosensor for Sensitive Alkaline Phosphatase Activity Analysis
摘要： Low-toxicity gold nanoclusters-decorated Ag@SiO2 (Au NCs-Ag@SiO2) nanocomposites modified plasmonic photoelectrodes were firstly fabricated to improve the photoelectric properties of Au NCs and practical application in biological detection. Through adjusting distance between Au NCs and plasmonic silver nanoparticles (Ag NPs), the photocurrent intensity of Au NCs enhanced by 3.8 times attributed to strong competition between enhancement functions of hot electron transfer, local electric field, light scattering effects and quenching functions of nonradiative energy transfer. Further comparison between experimental results and theoretical simulations were conducted to gain a deeper understanding toward the photoelectric enhancement mechanism. Moreover, Au NCs-Ag@SiO2 nanocomposites was successfully applied to the construction of photoelectrochemical (PEC) biosensors for sensitively detecting alkaline phosphatase activity. This proposed PEC biosensor showed a wide linear range from 0.04 to 400 U·L-1, and a low detection limit of 0.022 U·L-1.
关键词： Alkaline phosphatase,Gold nanoclusters,Photoelectrochemical,Ag@SiO2
更新于2025-09-23 15:19:57
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Synthesis of Water Soluble CuGaS2/ZnS Quantum Dots for Ultrasensitive Fluorescent Detection of Alkaline Phosphatase Based on Inner Filter Effect
摘要： Developing monitoring technique for alkaline phosphatase (ALP) is crucial due to the important role it plays in living cells. Here, a kind of biocompatible glutathione-modified CuGaS2/ZnS quantum dots (GSH-CGS/ZnS QDs) was used as a fluorescent substance and then fabricated “turn-off” fluorescent biosensor for detection of ALP by help of inner filter effect (IFE). Firstly, we prepared CuGaS2/ZnS (CGS/ZnS) QDs using solvothermal method and explored the efficient ligand (GSH) exchanges strategy for transferring oil-soluble CGS/ZnS QDs to aqueous phase. More importantly, we also explored the potential biological applications of the nanohybrid QDs. The obtained GSH-CGS/ZnS QDs emitted strong yellow fluorescence with the maximum excitation (400 nm) and emission (601 nm). Then, GSH-CGS/ZnS QDs were mixed with p-nitrophenylphosphate (PNPP) and ALP. PNPP could be hydrolyzed to p-nitrophenol (PNP) by help of catalysis of ALP, and the excitation spectrum of the GSH-CGS/ZnS QDs overlapped well with the absorption spectrum of PNP, so the fluorescence of GSH-CGS/ZnS QDs was initially quenched via the so-called “IFE”. Finally, a novel “turn-off” biosensor for sensitive detection of ALP in the range of 0.05-10 U L -1(R2 = 0.98) with a detection limit of 0.01 U L-1 was successfully obtained. Results indicated that I-III-VI2 nanocrystals have great potential for their promising biomedical application.
关键词： Inner filter effect,Alkaline phosphatase,GSH-CuGaS2/ZnS QDs,Fluorescent detection,Water solubility and biocompatibility
更新于2025-09-23 15:19:57
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Highly Sensitive Detection of Salbutamol by ALP-mediated Plasmonic ELISA Based on Controlled Growth of AgNPs
摘要： Salbutamol (SAL), a short-acting β-2 adrenergic receptor agonist, is an undesirable addition to livestock farming and used to improve the growth rates. A direct competitive colorimetric immunoassay for SAL was developed. The alkaline phosphatase (ALP)-mediated controlled growth of the prereduction silver nanoparticles (AgNPs) was used to achieve the highly sensitive, colorimetric detection of SAL through the plasmonic ELISA. Click chemistry reaction was used to synthesize salbutamol biotin label (SAL-Bio) to achieve signal amplification and specific binding with antibody. ALP can efficiently hydrolyze sodium L-ascorbyl-2-phosphate and generate L-ascorbic acid, thereby reducing Ag+ and forming AgNPs. The plasmon resonance absorption signals of AgNPs were enhanced along with a distinct color change. The limit of detection of SAL can be decreased to 26.14 pg/mL. The method offers a good technique for the detection of many small molecular contaminants, such as pesticide residues and veterinary drug residues in food and edible water.
关键词： Salbutamol,alkaline phosphatase,colorimetric detection,direct competitive immunoassay,plasmonic ELISA,silver nanoparticles
更新于2025-09-19 17:13:59
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Mimicking biological process to detect alkaline phosphatase activity using the vitamin B6 cofactor conjugated bovine serum albumin capped CdS quantum dots
摘要： This manuscript presents a novel bioanalytical approach for the selective ratiometric ?uorescent sensing of enzymatic activity of the alkaline phosphatase (ALP) in the biological samples. The probe was designed by conjugating the pyridoxal 5′-phosphate (PLP) over the surface of bovine serum albumin (BSA) stabilized CdS quantum dots (QDs) through the interaction of free amine present in BSA with the aldehyde group of PLP. The conjugation of PLP quenched the emission of QDs. Upon addition of the ALP, the emission of QDs was restored due to the dephosphorylation and the conversion of the functionalized PLP in to pyridoxal. With this probe, the ALP activity can be detected down to 0.05 U/L and also successfully applied for the detection of ALP activity in biological samples such as human serum and plasma.
关键词： Fluorescent sensor,Quantum dots,Vitamin B6 cofactors,Alkaline phosphatase
更新于2025-09-11 14:15:04
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Detection of Tumor Marker Using ZnO@Reduced Graphene Oxide Decorated with Alkaline Phosphatase-Labelled Magnetic Beads
摘要： Magnetic bead-based electrochemical enzyme-linked immunoassay (MB-eElisa) represents an attractive approach to develop cost-effective systems that are suitable for sensing complex biological samples. Its sensitivity essentially depends on the transduction efficiency of enzyme catalytic reactions into electrochemical responses. Here, an ultrahigh signal-to-noise alkaline phosphatase (ALP)-based MB-eElisa system is developed with a renewable zinc oxide-reduced graphene oxide nanocomposite modified carbon paste electrode (ZnO@rGO/CPE). This biosensing system employs one antibody decorated MBs (MB-Ab1) to capture a model tumor marker - carcinoembryonic antigen (CEA) - from samples, while other antibody coated gold nanoparticles-ALP bioconjugates (Ab2-AuNPs-ALP) convert 1-naphthyl phosphate (1-NPP) into electroactive 1-naphthol (1-NP). Beneficial from the unique electrochemical properties of a ZnO@rGO/CPE, inlcuding nearly zero background and significantly enhanced responses toward the hydrolyzed 1-NP in the presence of trace surfactants, the MB-eElisa system detects selectively CEA in a calibration range of 0.01-6.0 ng mL-1 and with a detection limit of 4.0 pg mL-1 (S/N = 3). Such a system was further applied to the detection of CEA in serum samples of cancer patients. The combination of MB-based ALP-linked immunoassay with a ZnO@rGO/CPE thus establishes a reusable and inexpensive electrochemical sensing platform for the rapid and sensitive detection of ultratrace biomarkers in complex biological samples.
关键词： Enzyme-linked immunoassay,Carcinoembryonic antigen,Alkaline phosphatase,Magnetic beads,Electrochemical biosensors
更新于2025-09-11 14:15:04
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Novel Fluorescent C2-Symmetric Sequential On-Off-On Switch for Cu2+ and Pyrophosphate and Its Application in Monitoring of Endogenous Alkaline Phosphatase Activity
摘要： A doubly armed hydrazone-based FLRHYDDFP probe selectively detects Cu2+ and pyrophosphate (PPi) ions through an colorimetric response-“colorless → yellow → colorless”- as well as “on-off-on” photonic switching response under physiological conditions in a sequential manner. The binding stoichiometries of the analytes Cu2+ and PPi were 1:2 and 2:4 for FLRHYDDFP-Cu2+ and Cu2+/PPi, respectively. The sequential sensing ability of FLRHYDDFP toward Cu2+ and PPi, attributed to effective complexation-aided d→π* electron transfer (ET) from Cu2+ to FLRHYDDFP and intramolecular charge/electron transfer from FLRHYDDFP to FLRHYDDFP+, resulted in the formation of a non-symmetric Cu2+ chelate that provided a yellow-colored solution with a significant bathochromic shift from 376 to 446 nm in the UV-Vis spectrum and quenching in the emission spectrum. Upon addition of PPi, Cu2+ was extruded from the complex, resulting in a revival of the fluorescence centered at 572 nm. Thus, sequential addition of Cu2+ and PPi yielded a colorless–yellow–colorless transition under visible light and on-off-on switching under 365-nm light (fluorescence). The lowest detection limits for Cu2+ and PPi, when using colorimetric and fluorimetric methods, were in the sub-micromolar and nanomolar levels, respectively. By exploiting this PPi sensing strategy, invitro as well as endogenous alkaline phosphatase activity could be monitored effectively, as demonstrated by exploiting the intracellular production or residual PPi in human salivary glands (normal) and cancer cell lines.
关键词： Endogenous Alkaline Phosphatase,C2v Symmetry,d→π* Electron Transfer,Intramolecular Charge/Electron Transfer,Human Salivary Gland Cells and Cancer Cells,Hydrazone
更新于2025-09-11 14:15:04