Detection Of Alkaline Phosphatase Activity Research Articles

Enhanced bipolar electrode electrochemiluminescence biosensor for ultrasensitive monitoring of alkaline phosphatase activity during osteoblast differentiation by integrating electrocatalytic and enzymatic strategies

Alkaline phosphatase (ALP) is an important biomarker that reflects osteoblast activity and bone growth. Accurately detecting ALP activity is of pivotal clinical significance for the diagnosis and differentiation of bone system diseases. In this work, an enhanced bipolar electrode electrochemiluminescence (BPE-ECL) biosensor based on enzyme catalysis and electrocatalysis was proposed for ultrasensitive detection of ALP in osteoblasts. Carbon nitride nanosheets (CNNS) were utilized as electrocatalysts to facilitate the electrochemical reaction of bipyridine ruthenium (Ru(bpy)32+) and tripropylamine (TPrA) in the reporting cell. Meanwhile, in the sensing cell, the target ALP catalyzed the conversion of p-aminophenyl phosphate monohydrate into p-aminophenol (p-AP). The p-AP was subsequently oxidized at the anode of the driving electrode, producing electrons and increasing the Faradaic current of BPE. The dual-signal amplification strategy, combining electrocatalysis and enzyme catalysis, resulted in a 10-fold enhancement of the ECL intensity of Ru(bpy)32+/TPrA. The BPE-ECL biosensor achieved ultrasensitive detection of ALP with a detection limit as low as 1.9×10−6 U/L, and was successfully applied to monitor ALP activity in osteoblast cells. Additionally, a portable smartphone imaging was developed for the visual detection of ALP. This research introduces an innovative BPE-ECL biosensor for the monitoring of ALP activity and point-of-care testing (POCT) in osteoblasts in clinical settings.

MOF-mediated cascade reaction system for ultrasensitive detection of alkaline phosphatase activity and organophosphorus pesticides.

Ametal-organic-framework (MOF) fluorescent sensor is reportedbased on NH2-MIL-101(Fe) propelled pesticide and alkaline phosphatase (ALP) catalytic reaction. Different from previous reports, a cascade reaction system combined with MOF structural changes to generate fluorescence was employed. The rationale is that ALP can hydrolyze L-ascorbic acid 2-phosphate (AAP) into L-ascorbic acid (AA), which can reduce Fe3+ to decompose structurally NH2-MIL-101(Fe), resulting in 2-aminoterephthalic acid (NH2-BDC) with intense fluorescence. The fluorescence can be decreased to different degrees due to inhibition of organophosphate pesticides (OPPs) on the activity of ALP. By taking chlorpyrifos (CPY) as the model compoundof anOPP pesticide and adding ALP and CPY into the NH2-MIL-101(Fe) framework, the resulting cascade reaction fluorescence sensors exhibit a good sensitivity for CPY and ALP sensing. The working ranges are 0.02-2 μg/L and 0.2-20 mU/mL with detection limits (LOD) of 5.31 ng/L and 0.05 mU/mL, respectively. The proposed sensor has been actually applied tosatisfactory detection of CPY and ALP in food and serum samples. This fluorescence-based assay may extend the application of MOF-based biosensors.

A novel, portable, and cost-effective turbidimetric sensor for sensitive alkaline phosphatase activity assay

The development of enzyme activity analysis methods is critical for precise and rapid assessments of enzyme activity levels within biological systems, facilitating a more profound comprehension of physiological functions and disease mechanisms. Alkaline phosphatase (ALP) participates in various physiological processes involving phosphate ester hydrolysis. Altered ALP activity levels are often indicative of different diseases, underscoring the necessity for accurate ALP activity determination in medical diagnostics. This study innovatively applies turbidity as a physical variable, proposing a turbidimetric sensor based on an enhanced ammonium molybdate reagent for phosphate analysis. By integrating this with the ALP substrate p-nitrophenyl phosphate, a turbidimetric sensor was devised and employed for ALP activity analysis. The proposed turbidimetric sensor demonstrated high sensitivity both for phosphate (0.18 μmol/L) and ALP activity (0.03 mU/mL) assay. In practical applications, this turbidimetric sensor has been effectively employed to detect ALP activity in mouse feces, showcasing its potential for auxiliary diagnosis of inflammatory bowel disease. Significantly, this novel turbidity-based approach offers not only swift and straightforward procedures but also remarkable portability and cost-efficiency. Requiring solely a handheld turbidimeter and eliminating the need for bulky instruments, this approach holds significant potential for point-of-care testing applications.

Fluorescence of europium activated by molecular-like silver clusters for the detection of alkaline phosphatase activity

Alkaline phosphatase (ALP) is abnormally expressed in some cancers and promotes the growth, metastasis, and invasion of cancer cells. The detection of ALP is of great significance for both pathological study and clinical detection. In this work, a europium (Eu)-based fluorescence detection sensor was prepared in a mild reaction condition. LaF3:Eu nanoparticles was mixed with ethylene imine polymer (PEI) and Ag+ ions. PEI was used as stabilizer and reducing agent, and Ag+ ions were reduced as molecular-like silver clusters (ML-Ag NCs). The fluorescence of LaF3:Eu nanoparticles was enhanced by ML-Ag NCs through energy transfer. When ascorbic acid 2-phosphate (AAP) was hydrolyzed to ascorbic acid (AA) in the presence of ALP, AA reduced Ag+ ions to silver nanoparticles (Ag NPs) and quenched the fluorescence of LaF3:Eu/PEI/Ag. The activity of ALP was detected by measuring the fluorescence intensity of Eu3+ at 618 nm. In the concentration range from 2.0 to 16.0 U/L, the fluorescence intensity ratio ((F0–F)/F0) had a linear relationship with the logarithm of ALP concentration. The limit of detection (LOD) was 1.3 U/L. Moreover, the ALP activity was detected successfully in cancer cells by this method. The sensing platform has application potential in the detection of ALP activity in biological systems.

The Effect of Electrospun Scaffold Loaded With Taraxasterol Microspheres on the Proliferation and Differentiation of Osteoblasts.

This study aims to observe the effect of electrospun scaffolds loaded with taraxasterol microspheres on the proliferation and differentiation of osteoblasts. Taraxasterol microspheres were prepared by desolventization and electrostatic adsorption technology. The structure of the microspheres was observed under transmission electron microscopy. The drug microspheres were loaded into electrospinning using electrospinning technology, followed by scanning electron microscopy and elemental analysis. Osteoblasts were cultured in vitro, and the effects of drug carriers on osteoblast proliferation and differentiation were observed through Cell Counting kit 8 (CCK-8) cell proliferation detection and alkaline phosphatase activity detection. Transmission electron microscopy showed that the prepared drug microspheres have a double-layer structure, which can effectively reduce the sudden release of drugs. The electrospinning had a porous three-dimensional structure between them, which was conducive to cell adhesion. After loading microspheres, there was a significant difference in electrospinning diameter and nodular protrusions, energy dispersive spectroscopy (EDS) elemental analysis showed that the proportion of nitrogen elements increased significantly after the addition of microspheres, a CCK-8 detection showed that drug carrier scaffolds loaded with taraxasterol had a promoting effect on osteoblast proliferation (P<0.05). Alkaline phosphatase detection showed that drug carrier scaffolds loaded with taraxasterol can promote early differentiation of osteoblasts (P>0.05). Electrospinning loaded with taraxasterol microspheres can promote osteoblast adhesion, proliferation, and differentiation.

PfAgo-based dual signal amplification biosensor for rapid and highly sensitive detection of alkaline phosphatase activity.

APyrococcus furiosus Argonaute (PfAgo)-based biosensor is presented for alkaline phosphatase (ALP) activity detection in which the ALP-catalyzed hydrolysis of 3'-phosphate-modified functional DNA activates the strand displacement amplification, and the amplicon mediates the fluorescent reporter cleavage as a guide sequence of PfAgo. Under the dual amplification mode of PfAgo-catalyzed multiple-turnover cleavage activity and pre-amplification technology, the developed method was successfully applied toALP activity determination with a detection limit (LOD) of 0.0013 U L-1 (3σ) and a detection range of 0.0025 to 1 U L-1 within 90min. The PfAgo-based method exhibits satisfactory analytic performance in the presence of potential interferents and in complex human serum samples. The proposed method shows several advantages, such as rapidanalysis, high sensitivity, low-cost, and easy operation, and has great potential in disease evolution fundamental studies and clinical diagnosis applications.

Enzyme-responsive aptasensor based on the functionalized fluorescent protein chromophore derivative for the detection of alkaline phosphatase activity

Fluorescent proteins (FPs) based sensing strategies have been widely developed in bioanalytical applications. However, it still remains a challenge to realize the efficient and precise analysis. Recently, FPs chromophore and its derivatives with favorable optical properties are well-designed to simulate and replace the function of FPs by specifically binding to the selected fluorescent light-up aptamers (FLAPs), it is worthy note that there is still a lack of systematic approaches to remold these FPs mimics with enzyme-responsive functions. Taking alkaline phosphatase (ALP) as a research model, we here propose an ALP-responsive fluorescent DNA aptasensor (p-DAA) by utilizing a truncated Lettuce (tLet-10) FLAP and a phosphorylated DFHBI-derivative (ALP-DFSS) for achieving ALP activity analysis. Taking the HBI-chromophore as the remolding molecular template, ALP-DFSS has been successfully synthesized and characterized to response to ALP activity. With phosphate group substitution in ALP-DFSS, the decayed fluorescence of p-DAA can be observed by forming the complex of tLet-10/ALP-DFSS. While the turn-on fluorescence of p-DAA will be obtained by the ALP-triggered dephosphorylation process and further exhibit the label-free, fast-response, specific, and sensitive detection performances for both evaluating ALP activity and the inhibition efficiency of ALP inhibitor. Moreover, p-DAA allow the spiked ALP analysis in serum samples and is also applied for realizing the visual differentiation between normal cell line and cancer cell line by responding the endogenous ALP, which holds the great potential in guiding the chromophores functionalization and exploring aptasensing related biological research.

Novel hydrogel pillar array based ratiometric multicolor fluorescence biosensor for visual detection of alkaline phosphatase activity

Enzyme-induced in-situ fluorescence is crucial for the development of biosensing mechanisms and correlative spectroscopic analysis. Inspired by simple p-aminophenol (AP)-controlled synthesis and the specific catalytic reaction of 4-aminophenyl phosphate (APP) triggered by alkaline phosphatase (ALP), our research proposed a strategy to prepare carbon dots (CDs) as fluorescent signals for ALP detection using AP and 3-aminopropyltrimethoxysilane (APTMS) as the precursors. The further constructed ratiometric fluorescence sensor reduced the detection limit of ALP to 0.075 μU/mL by a significant margin. Considering the need for point-of-care testing (POCT), we chose agarose for the preparation of portable hydrogel sensors so that even untrained personnel can quickly achieve semi-quantitative visual detection of ALP using colorimetric cards. These results demonstrate the practical applicability of ratiometric fluorescence sensing hydrogel pillar arrays, which are important for high-sensitivity, visualization, and portable rapid enzyme activity assays.

Detection of alkaline phosphatase activity with a CsPbBr3/Y6 heterojunction-based photoelectrochemical sensor.

An ultra-sensitive photoelectrochemical (PEC) sensor based on perovskite composite was developed for the determination of alkaline phosphatase (ALP) in human serum. In contrast toCsPbBr3 or Y6 that generated anodic current, the heterojunction of CsPbBr3/Y6 promoted photocarriers to separate and generated cathodic photocurrent. Ascorbic acid (AA) was produced by ALP hydrolyzing L-ascorbic acid 2-phosphate trisodium salt (AAP), which can combine with the holes on the photoelectrode surface, accelerating the transmission of photogenerated carriers, leading to enhanced photocurrent intensity. Thus, the enhancement of PEC current was linked to ALP activity. The PEC sensor exhibits good sensitivity for detection of ALP owing to the unique photoelectric properties of the CsPbBr3/Y6 heterojunction. The detection limit of the sensor was 0.012 U·L-1 with a linear dynamic range of 0.02-2000 U·L-1. Therefore, this PEC sensing platform shows great potential for the development of different PEC sensors.

Label-free and sensitive assay for ICP-MS determination of alkaline phosphatase activity via manganese target

As an essential and universal enzyme, alkaline phosphatase (ALP) has been identified as an important biomarker of various diseases, thus highly sensitive assay of ALP activity is of great significance. Herein, a label-free and sensitive ICP-MS based assay was developed for ALP activity detection using MnO2 nanosheets (MnO2 NS) as the element target source. ALP triggered the hydrolysis of ascorbic acid-2-phosphate (AAP) to produce reductive ascorbic acid (AA), followed with the decomposition of MnO2 NS to Mn2+ ions, which were quantified directly by ICP-MS after selective separation of MnO2 NS and Mn2+ ions simply by filtration, and no further elemental labelling was needed. Under the selected conditions, the limit of detection (LOD) was 0.007 U L-1 for ALP. Additionally, this assay was also extended to investigate the inhibition effect of ALP inhibitor (Na3VO4) with reasonable results. To our knowledge, this is the first endeavor for ALP activity detection using ICP-MS, which holds great promise for the early clinical diagnosis and biomedical research on ALP.

Morinda officinalis polysaccharide promotes the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells via microRNA-210-3p/scavenger receptor class A member 3.

Morinda officinalis polysaccharide (MOP) is the bioactive ingredient extracted from the root of Morinda officinalis, and Morinda officinalis is applied to treat osteoporosis (OP). The purpose of this study was to determine the role of MOP on human bone marrow mesenchymal stem cells (hBMSCs) and the underlying mechanism. HBMSCs were isolated from bone marrow samples of patients with OP and treated with MOP. Quantitative real-time polymerase chain reaction was adopted to quantify the expression of microRNA-210-3p (miR-210-3p) and scavenger receptor class A member 3 (SCARA3) mRNA. Cell Counting Kit-8 assay was employed to detect cell viability; Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling assay and flow cytometry were adopted to detect apoptosis; Alkaline Phosphatase (ALP) activity assay kit was applied to detect ALP activity; Western blot was executed to quantify the expression levels of SCARA3, osteogenic and adipogenic differentiation markers. Ovariectomized rats were treated with MOP. Bone mineral density (BMD), serum tartrate-resistant acid phosphatase 5b (TRACP 5b), and N-telopeptide of type I collagen (NTx) levels were assessed by BMD detector and Enzyme-linked immunosorbent assay kits. It was revealed that MOP could promote hBMSCs' viability and osteogenic differentiation and inhibit apoptosis and adipogenic differentiation. MOP could also upregulate SCARA3 expression through repressing miR-210-3p expression. Treatment with MOP increased the BMD and decreased the TRACP 5b and NTx levels in ovariectomized rats. MOP may boost the osteogenic differentiation and inhibit adipogenic differentiation of hBMSCs by miR-210-3p/SCARA3 axis.

Icariin promotes osteogenic differentiation of human bone marrow mesenchymal stem cells by regulating USP47/SIRT1/Wnt/β-catenin.

Icariin has been shown to promote osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). However, the underlying molecular mechanism by which Icariin regulates osteogenic differentiation needs to be further revealed. The viability of BMSCs was assessed by cell counting kit 8 assay. BMSC osteogenic differentiation ability was evaluated by detecting alkaline phosphatase activity and performing alizarin red S staining. The protein levels of osteogenic differentiation-related markers, sirtuin 1 (SIRT1), ubiquitin-specific protease 47 (USP47), and Wnt/β-catenin-related markers were determined using western blot. SIRT1 mRNA level was measured using quantitative real-time PCR. The regulation of USP47 on SIRT1 was confirmed by ubiquitination detection and co-immunoprecipitation analysis. Icariin could promote BMSC osteogenic differentiation. SIRT1 expression was enhanced by Icariin, and its knockdown suppressed Icariin-induced BMSC osteogenic differentiation. Moreover, deubiquitinating enzyme USP47 could stabilize SIRT1 protein expression. Besides, SIRT1 overexpression reversed the inhibiting effect of USP47 knockdown on BMSC osteogenic differentiation, and USP47 knockdown also restrained Icariin-induced BMSC osteogenic differentiation. Additionally, Icariin enhanced the activity of the Wnt/β-catenin pathway by upregulating SIRT1. Icariin facilitated BMSC osteogenic differentiation via the USP47/SIRT1/Wnt/β-catenin pathway.

A two-dimensional iron-doped carbon-based nanoenzyme with catalase-like activity for the detection of alkaline phosphatase and ascorbate oxidase

Herein, we successfully synthesized two-dimensional iron-doped carbon-based nanosheets (Fe–N800 CS) with catalase-like activity through doping Fe into Zn MOF and introducing graphitic C3N4 (g-C3N4). The interaction of the Fe–N800 CS with hydrogen peroxide could generated abundant reactive oxygen species (ROS) and further oxidize o-Phenylenediamine (OPD) to 2,3-diaminophenazine (DAP) which has constant fluorescence at 560 nm. Ascorbic acid (AA) could be generated via the hydrolysis reaction between alkaline phosphatase (ALP) and ascorbic acid 2-phosphate (AAP). AA can be oxidized to dehy-droascorbic acid (DHA) by ROS, and then combined with OPD to generate 3-(1,2-dihydroxyethyl)furo[3,4b]-quinoxaline (QXD) with fluorescence at 440 nm, which could increase as the concentration of AA enhanced. DHA could also be generated through oxidation of AA by ascorbate oxidase (AAO). Thus, by monitoring the fluorescence ratio (I560/I440), a ratiometric fluorescence biosensing platform for ALP and AAO was established with the linear ranges in 0.2–10 U/L and 1–60 U/L, respectively. The limit of detection for ALP and AAO were 0.12 U/L and 0.59 U/L. Furthermore, the biosensing platform was successfully applied for the detection of ALP and AAO activity in human serum samples. This work provides a potential tool for future biomedical diagnostics.

Nitrogen and phosphorus uptake kinetics in cultures of two novel picoplankton groups responsible for a recent bloom event in a subtropical estuary (Indian River Lagoon, Florida)

IntroductionSuccessful management and mitigation of harmful algal blooms (HABs) requires an in-depth understanding of the physiology and nutrient utilization of the organisms responsible. We explored the preference of various nitrogen (N) and phosphorus (P) substrates by two novel groups of HAB-forming phytoplankton originating from the Indian River Lagoon (IRL), Florida: 1) a consortium of picocyanobacteria (Crocosphaera sp. and ‘Synechococcus’ sp.) and 2) ananochlorophyte (Picochlorum sp.).MethodsShort-term kinetic uptake experiments tested algal use and affinity for inorganic and organic N substrates (ammonium (NH4+), nitrate (NO3-), urea, and an amino acid (AA) mixture) through 15N and 13C isotope tracing into biomass.ResultsPicocyanobacteria exhibited Michaelis-Menten type uptake for the AA mixture only, while nanochlorophytes reached saturation for NH4+, the AA mixture, and urea at or below 25 µM-N. Both picocyanobacteria and nanochlorophyte cultures had highest affinity (Vmax/Ks) for NH4+ followed by the AA mixture and urea. Neither culture showed significant uptake of isotopically-labeled nitrate. Disappearance of glucose-6-phosphate (G6P) added to culture medium suggesting use of organic P by both cultures was confirmed by detection of alkaline phosphatase activity and the tracing of 13C-G6P into biomass.DiscussionTogether, our results suggest that these HAB-forming phytoplankton groups are able to use a variety of N and P sources including organic forms, and prefer reduced forms of N. These traits are likely favorable under conditions found in the IRL during periods of significant competition for low concentrations of inorganic nutrients. Bloom-forming phytoplankton are therefore able to subsist on organic or recycled forms of N and P that typically dominate the IRL nutrient pools.

Effect of composite resin monomer BisGMA on odontogenic differentiation of human dental pulp stem cells

Objective : To study the effect of composite resin monomer BisGMA on human dental pulp stem cell (hDPSCs) odontoblasts differentiation, and explore the effect of composite resin filling teeth on dentin formation. Material and Methods : separate and culture hDPSCs, identify cell phenotype by flow cytometry, and induce staining to assess multidirectional differentiation potential. The hDPSCs was stimulated with different concentrations of monomeric BisGMA, and the odontoblast differentiation capacity of each group was determined by CCK-8 assay, alkaline phosphatase activity detection, and q-PCR. Results: CCK-8 showed that the addition of 0.5 mM —— 8 mM BisGMA affected the cell increment, but no significant difference; the concentration of 0.5 mM —— 8 mM BisGMA reduced the cellular alkaline phosphatase activity and further decreased the activity with increasing concentration.The q-PCR results also showed that monomeric BisGMA inhibited the dentin-related gene OC (osteocalcin), DSPP (dentin sialophosphoprotein)Expression, and with the concentration increases, the inhibition is more obvious of. Conclusion : Composite resin monomer BisGMA has a negative effect on odontogenic differentiation of human dental pulp stem cells

A dual-mode sensing platform for electron spin resonance and UV-vis detection of alkaline phosphatase based on Cu-based metal-organic frameworks.

Alkaline phosphatase (ALP) is an indispensable hydrolase in living organisms and the abnormality of ALP activity is correlated with a variety of diseases. Exploring ALP activity is important for clinical diagnosis and biomedical research to understand its physiological function. In this study, a dual-mode biosensing platform was constructed based on Cu-based metal-organic frameworks (Cu-MOFs) for electron spin resonance (ESR) and ultraviolet-visible (UV-vis) sensing of ALP. Cu-MOFs, as peroxidase mimics, catalyzed the decomposition of hydrogen peroxide (H2O2) and the generation of reactive oxygen species (ROS) which could oxidize ABTS into ABTS˙+ with good ESR and UV-vis signals. Pyrophosphate ions (PPi) with high affinity to Cu2+ in Cu-MOFs could suppress the peroxidase-like activity of Cu-MOFs, and ALP could hydrolyze PPi, resulting in the recovery of Cu-MOF catalytic activity. Thus, a quantitative dual-mode method for detection of ALP activity was established with good linearity in the range of 0-42 U L-1 and limits of detection as low as 0.386 and 0.523 U L-1 respectively for ESR and UV-vis detection. Benefiting from its high sensitivity and excellent selectivity, this method was applied for ALP detection in human serum and satisfactory recoveries were achieved. The off-on dual-mode sensing platform is more reliable than the single-mode sensor and shows merits like simple operation and cost-friendliness, making it have great potential in the diagnosis of ALP-related diseases.

Effects of fine particulate matter on bone mass and osteogenic differentiation of bone marrow mesenchymal stem cells in mice

To observe the effects of exposure to fine particulate matter(PM_(2.5)) on bone mass, microstructure, biomechanical properties, and osteogenic differentiation ability of bone marrow mesenchymal stem cells(BMSCs) in mice. A total of 16 C57BL/6J mice aged 8 weeks were randomly divided into control group(NS group) and PM_(2.5) exposure group(PM group). NS group was given normal saline, PM group was given 14 mg/kg PM_(2.5) suspension, 50 μL, poisoning every 3 day. After 10 weeks, the lungs of mice were taken for HE staining, and the left tibia was taken for Micro CT detection to analyze parameters related to cancellous and cortical bone. The right tibia was taken for HE staining to observe changes in bone trabeculae. Immunohistochemical staining was used to detect type I collagen(Col I), osteoprotegerin(OPG), and nuclear factor-κB receptor activating factor ligand(RANKL) protein expression, tartrate resistant acid phosphatase(TRAP) staining for detection of osteoclasts. Extract primary BMSCs from bilateral femurs, induce osteogenesis, and then perform alkaline phosphatase(ALP) staining to detect ALP activity, alizarin red staining to detect bone mineralization ability, real-time PCR to detect osteocalcin(OCN), ALP, OPG, and RANKL mRNA expression, and biomechanical testing to test the mechanical properties of the femur. Compared with the NS group, the pulmonary alveolar structure of the PM group mice was disrupted and a large number of inflammatory cells gathered. Prompt for successful PM_(2.5) poisoning operation. Micro CT result showed that the bone mineral density(BMD) and bone volume fraction(BV/TV) of the PM group mice were 276.959±15.152 mg/cm~3 and 0.208%±0.009%, respectively. The NS group had 316.709±28.205 mg/cm~3 and 0.236%±0.019%, respectively. The PM group was lower than the NS group(P&lt;0.05), but the trabecular number(Tb. N) There was no statistically significant difference in parameters such as trabecular thickness(Tb. Th) and trabecular separation(Tb. SP)(P&gt;0.05). The HE staining result of the tibia showed that the trabeculae in the NS group were thick, dense, and uniform. The bone trabeculae in the PM group were slender, with a decrease in number, widened spacing, and sparse arrangement. The expression of Col I(0.023±0.009) and OPG(0.036±0.010) in the PM group increased compared to the NS group(0.079±0.007, 0.059±0.012), while the expression of RANKL(0.036±0.006) decreased compared to the NS group(0.022±0.002)(P&lt;0.05); The number of TRAP positive particles increased in the PM group. The experimental result after osteoinduction of BMSCs in mice showed that compared with the NS group, the PM group had a decrease in the number of ALP positive cells and a decrease in the number of calcium nodules. The relative expression of ALP, OCN, and OPG mRNA in the PM group(0.375±0.021, 0.585±0.088, 0.768±0.112) was significantly reduced compared to the NS group(1.001±0.043, 1.006±0.132, 1.002±0.086), while the relative expression of RANKL mRNA(1.278±0.118) was increased compared to the NS group(1.001±0.057)(P&lt;0.05). The biomechanical experimental result showed that the maximum deflection of the NS group was 0.337±0.031 mm, while the maximum deflection of the PM group was 0.258±0.041 mm. Compared with the NS group, the maximum deflection of the PM group decreased significantly(P&lt;0.05), and the maximum stress and maximum load showed a decreasing trend, but the difference was not statistically significant(P&gt;0.05). After 10 weeks of exposure to PM_(2.5), it can affect the bone health of mice, and its mechanism may be related to increased osteoclast activity and inhibition of the osteogenic differentiation ability of BMSCs.

A controllable design of ZIF-67 based magnetic carbon nanotubes as efficient oxidase mimetics for sensitive detection of alkaline phosphatase in serum

The activity of alkaline phosphatase (ALP) is related to various pathological processes. Therefore, developing an ALP activity detection technology with high sensitivity and accuracy is of great significance for clinical diagnosis and cancer screening. To solve uncontrollable carbon nanotubes (CNTs) structure and lack of solubility, FeCo hollow nanocages (HNCs)@CNTs catalysts were prepared by facile pyrolysis of ZIF-67 precursor mixed with Fe-Co catalyst, displaying an oxidase-like activity. From the characterization, formation of CNTs was observed on the surface of FeCo HNCs@CNTs with the mole ratio of Fe3+ to Co2+ of 3:1. Density functional theory calculations demonstrated that the performed catalytic activity of FeCo HNCs@CNTs derived from active orbital of Co-3d band, which enabled the activation and decomposition of O2 with a feasible thermodynamic process. ·O2− and 1O2 were the main reactive oxygen species as electron acceptors. ALP catalyzed the hydrolysis of ascorbic acid 2-phosphate (AAP) to convert it into ascorbic acid (AA), which could effectively reduce the FeCo HNCs@CNTs-mediated chromogenic reaction of TMB oxidation. The performance of the FeCo HNCs@CNTs-linked biosensing assay showed a broad detection range from 0.1 U/L to 150 U/L and a relatively low limit of detection of 0.083 U/L. The ALP activity of the mouse serum sample obtained by the proposed biosensing assay was highly consistent with that via the clinical method, indicating a promising technology in biomolecule detection.

Fluorescence switch-on detection of alkaline phosphatase activity and adenosine triphosphate using vitamin B6 cofactor conjugated Mn-doped ZnS QDs

This study introduces a fluorescent nanoprobe PLP@l-Cyst-Mn-ZnS obtained through post-functionalization of l-cysteine capped Mn-doped ZnS quantum dots (l-Cyst-Mn-ZnS QDs) with pyridoxal 5′-phosphate (PLP). The functionalization process involves the formation of a Schiff base between PLP and l-Cyst, leading to the quenching of fluorescence emission at 603 nm. The quenched PLP@l-Cyst-Mn-ZnS acts as a highly sensitive fluorescent turn-on probe for alkaline phosphatase (ALP) and adenosine triphosphate (ATP). ALP catalytically dephosphorylates the functionalized PLP into pyridoxal (PL). In contrast, the interaction of ATP with the functionalized PLP suppresses the electron transfer process leading to the recovery of fluorescence emission at 603 nm. This nanoprobe exhibits exceptionally high sensitivity enabling the estimation of ALP and ATP concentrations as low as 0.006 U/L and 0.14 µM, respectively. The practical applicability of PLP@l-Cyst-Mn-ZnS is demonstrated by accurately quantifying spiked ALP and ATP in human serum and plasma. This work highlights the potential of PLP@l-Cyst-Mn-ZnS as a versatile and efficient nanoprobe for biomedical applications.

Inter filter effect between fluorescent copper nanoclusters and Cr(VI) and its application for probing the activity of alkaline phosphatase

Herein, a novel fluorescent sensing strategy for the detection of alkaline phosphatase activity (ALP) was successfully established using highly luminescent glutathione-stabilized copper nanoclusters (GSH-CuNCs) as fluorescent probe. The GSH-CuNCs were synthesized with GSH as stabilizer and ascorbic acid (AA) as reductant. The optical properties of GSH-CuNCs were further investigated using fluorescence and UV–vis spectrophotometry. And its sensing ability for AA and ALP were explored. The fluorescence intensity of GSH-CuNCs was strongly quenched by Cr(VI) due to the inner filter effect (IFE). However, in the presence of AA, the fluorescence of GSH-CuNCs/Cr(VI) probes was restored due to the weakening of the IFE. It also exhibited a good linear range to the concentration of AA in the range of 0.1–500 μM, and the detection limit was 20 nM. In addition, it has been found that the substrate ascorbic acid 2-phosphate (AA2P) had no effect on the fluorescence of the (GSH-CuNCs)-Cr(VI) probe. Since ALP could specifically hydrolyze AA2P into AA, the emission intensity of the probes was restored by an ALP-triggered reaction. As a result, ALP was sensitively and selectively quantified with a wide linear range of 0.1 mU•mL−1 to 200 mU•mL−1 and a low detection limit of 0.02 mU•mL−1. In order to evaluate the practicality of the detection strategy, ALP in real sample analysis was also determined. The results showed that the recoveries and relative standard deviations were acceptable towards the probes. The proposed biosensor could be applied in fields of environmental and biological analysis.