Sodium Citrate Buffer Solution Research Articles

Paintable, Fast Gelation, Highly Adhesive Hydrogels for High-fidelity Electrophysiological Monitoring Wirelessly.

High-fidelity wireless electrophysiological monitoring is essential for ambulatory healthcare applications. Soft solid-like hydrogels have received significant attention as epidermal electrodes because of their tissue-like mechanical properties and high biocompatibility. However, it is challenging to develop a hydrogel electrode that provides robust contact and high adhesiveness with glabrous skin and hairy scalp for high-fidelity, continuous electrophysiological signal detection. Here, a paintable, fast gelation, highly adhesive, and conductive hydrogel is engineered for high-fidelity wireless electrophysiological monitoring. The hydrogel, consisting of gelatin, gallic acid, sodium citrate, lithium chloride, glycerol, and Tris-HCl buffer solution exhibits a reversible thermal phase transition capability, which endows it with the attributes of on-skin applicability and fast in situ gelation with 15 s, thereby addressing the aforementioned limitations. The introduction of gallic acid enhances the adhesive properties of the hydrogel, facilitating secure electrode attachment to the skin or hairy scalp. To accentuate the potential applications in at-home electrophysiological health monitoring, the hydrogel electrodes are demonstrated for high-fidelity electrocardiogram recording for one hour during various daily activities, as well as in simultaneous electroencephalogram and electrocardiogram recording during a 30 min nap.

Enhancing efficiency in ethanol production from high solid corn stover: Insights into enzymatic hydrolysis parameters and cellulase recovery

BackgroundThe simultaneous saccharification and co-fermentation (SSCF) at high solid loading is an effective approach to improve the economic feasibility of bioethanol. MethodsIn this study, the high-solid SSCF of superfine grinding corn stover was treated with cheap and readily available deionized water (DW) instead of sodium citrate buffer solution (SCBS). Additionally, the evaluation of temperature, enzyme loading, solid loading, and cellulose recovery were carried out to determine their impact on ethanol production. Significant FindingsThe results of the analysis indicated that replacing SCBS with DW had negligible effects on the SSCF of ethanol and byproducts (acetic acid and glycerol). The ethanol yield increased by 18 % at 35 °C compared to the yield at 30 °C. As enzyme loading increased, more cellulose active sites in corn stover were bound by cellulase, which increased the ethanol yield by improving the efficiency of enzymatic hydrolysis. The SSCF process didn't incorporate any buffer, resulting in an even higher ethanol titer (55.42 g/L). Furthermore, the cellulase productivity increased by 71 % after recovery, compared to the non-recovery. The results indicated that the optimized SSCF process is a potential technique for producing bioethanol on a commercial level because it improves the production efficiency while keeping costs low.

Subtle Intricacies Identified during Streptozotocin-Induced Diabetes in Wistar Rats

Abstract: Aim: This study aimed to establish the dose of streptozotocin required to induce Type -1 diabetes in Wistar rats. Background: Streptozotocin is currently employed worldwide to induce insulin-dependent diabetes mellitus also known as Type 1 diabetes mellitus in experimental animals. Though many reports on the use of streptozotocin induction of diabetes are reported in the literature, they were not reproducible. Moreover, there was no mention of the mortality associated with the same as well as the conditions followed during the study. Materials and Methods: In the present study, the dose, route, and solvent used for streptozotocin were investigated. Various doses of streptozotocin 55, 50, 40, and 35mg/kg dissolved in either freshly prepared cold 10mM sodium citrate buffer (pH 4.5) or normal saline solution was administered intraperitoneally as well as intravenously. For intraperitoneal administration, the dose-volume was 10mL/kg whereas for intravenous administration the dose-volume was 2mL/Kg. Different routes were employed to ascertain the cause of mortality for which an autopsy was performed. Besides mortality rate was also determined. Results and Discussion: The findings of the study revealed that a 35-40mg/kg dose of streptozotocin showed less percentage mortality and successful induction of diabetes. Conclusion: Mortality (10-20%) was observed at a dose of 35-40mg/kg streptozotocin. Therefore, streptozotocin (35-40mg/kg) was confirmed to be safe and effective for the induction of diabetes in Wistar rats. This paper highlights subtle intricacies observed during induction of diabetes in Wistar rats using streptozotocin Keywords: Male Wistar rats, Streptozotocin, Type-1 diabetes, 5% dextrose, Mortality, Normal saline solution.

Pharmacological Studies on the Antidiabetic, Antioxidant, and Antimicrobial Efficacies of Commiphora myrrha Resin in Streptozotocin-Induced Diabetes in Rats: A Preclinical Study.

The aqueous extracts of MAE were phytochemically analyzed, and the results revealed the presence of high concentrations of tannins, sterols, and isoprenoids (terpenoids), while steroids and flavonoids were found in moderate concentrations. The plant extract showed promising inhibition of the growth of gram-positive and gram-negative pathogens. It also showed that MAE has potential antihyperglycemic and antioxidant activities. Microscopic examination of the pancreas showed degenerative changes and atrophy associated with dilatation of the exocrine ducts in the STZ-induced diabetic rats, while the treatment revealed that the Langerhans islets were close to normal without any histopathological alteration. The present results suggested that an aqueous extract of MAE could be considered an efficient antidiabetic, antioxidant, and antimicrobial treatment in the future.

Evaluating the Effect of Residual Lignin Contents and Fermentation Systems on Bioethanol Production

Peroxide-acetic acid (Peroxide-HAc) pretreatment is a simplified and cost-effective technology due to its mild conditions without the catalysis of strong acids, which was introduced to treat sugarcane bagasse (SCB) in this paper. Then pretreated SCB was used to produce bioethanol using thermophilic Saccharomyces cerevisiae in deionized water (DW) and sodium citrate buffer solution (SCS) fermentation systems, respectively. Results: showed that peroxide-HAc pretreatment can selectively remove lignin and change morphological structures, thus positively increasing saccharification and fermentation efficiency downstream. SCB pretreated at 100 °C obtained the lowest residual lignin content of 2.88% and achieved the highest ethanol yield of 92.10% (0.45 g/g-biomass) in DW system. In particular, SCS can decrease the residual sugars content of pretreated SCB during simultaneous saccharification and co-fermentation (SSCF) process. The addition of Tween 80 improved SSCF of SCB pretreated at 80 °C likely because Tween 80 can block residual lignin adsorption with enzymes. The concentration of acetic acid and glycerol byproducts from SCB pretreated at 80 °C can be decreased by SCS and DW systems, respectively, comparing to SCS and DW systems with additing Tween 80. This study provided a systematic process route for the bioethanol production by mild pretreatment method.

Effect of Musk Tongxin Dropping Pill on Myocardial Remodeling and Microcirculation Dysfunction in Diabetic Cardiomyopathy.

Objective To explore the effect of Musk Tongxin Dropping Pill (MTDP) on myocardial remodeling and microcirculation dysfunction in diabetic cardiomyopathy (DCM). Methods Forty male SD rats were randomly divided into control group (control group, n = 10), DCM model group (DCM group, n = 10), DCM model + pioglitazone group (DCM + PLZ group, n = 10), and DCM model + MTDP group (DCM + MTDP group, n = 10). An intraperitoneal single injection of 65 mg/kg streptozotocin (STZ) was used to establish rat model of DCM and the rats in control group were treated with the same dose of sodium citrate buffer solution. DCM + PLZ group was treated with 3 mg/kg/d PLZ by ig after modeling, DCM + MTDP group was treated with 22 mg/kg/d MTDP by ig, and DCM group was treated with 2 ml/kg/d sodium carboxymethyl cellulose (CMC-Na) by ig. The general condition of rats was continuously observed. After intervening for 3 weeks, the random blood glucose of rats was detected by tail vein, and the echocardiography examination was performed. Blood specimens were collected from the abdominal aorta, serum nitric oxide (NO) and endothelin-1 (ET-1) were detected to estimate endothelial function, and tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), IL-1β, malondialdehyde (MDA), and superoxide dismutase (SOD) were detected to observe the changes of inflammation and oxidative stress indexes. The heart mass index (HMI) was calculated through the ratio of heart mass (HM) to the corresponding body mass (BM). Myocardial pathological tissue staining was performed. Results Compared with control group, blood glucose in other three groups was higher. Left ventricular end systolic diameter (LVSD) and left ventricular end diastolic diameter (LVDD) in DCM group showed a significant increase, while left ventricular ejection fraction (LVEF) and heart rate (HR) in this group displayed an obvious decrease (P < 0.01). BM and HM in DCM group exhibited a reduction, and HM/BM × 103 revealed an apparent increase (P < 0.01). The levels of serum NO and SOD were distinctly downregulated (P < 0.01), and the levels of ET-1, MDA, TNF-α, IL-1β, and IL-6 were remarkably upregulated (P < 0.01). Compared with DCM group, a significant decrease was observed in LVSD and LVDD in DCM + MTDP group, while LVEF and HR obviously increased (P < 0.05). BM and HM indicated an apparent increase, but HM/BM ×103 reduced distinctly (P < 0.01). The levels of serum NO and SOD were markedly upregulated (P < 0.05), and the levels of ET-1, MDA, TNF-α, IL-1β, and IL-6 were significantly downregulated (P < 0.05). HE staining showed that myocardial cells arranged neatly in the control group but not in the DCM group. The intercellular space between myocardial cells in DCM group increased, accompanied by damage of myocardial fibers and infiltration of inflammatory cells. Masson staining displayed an increase in interstitial collagen fibers in DCM group. Carstairs staining showed that microembolization occurred in the myocardium in DCM group, while in DCM + MTDP and DCM + PLZ groups the corresponding myocardial pathological changes were significantly improved. Conclusions MTDP might show a positive effect on myocardial remodeling and microcirculation dysfunction in DCM rats.

Soil Protein as a Rapid Soil Health Indicator of Potentially Available Organic Nitrogen

Core IdeasThe extraction protocol for “glomalin” extracts protein from a wide variety of sources.The termglomalinorglomalin‐related soil proteinis inaccurate and limits the utility of the method.The extracted protein pool should be viewed more broadly as a soil health indicator of potentially available organic N.Increased interest in practical, routine evaluation of soil health has created a need for rapid and inexpensive indicators that reflect soil nitrogen (N) status. Here we propose a soil protein measurement as an indicator of a functionally relevant and sensitive pool of organic N that can be rapidly quantified in soil testing laboratories. The procedure is based on a method that was historically used to measure “glomalin,” a pool putatively of arbuscular mycorrhizal fungal origin. Laboratory validation experiments demonstrate that the procedure extracts proteins from a wide range of sources, not just glomalin, and that continued use of the termglomalinis inaccurate and limits the application of the method. Therefore, we propose that the pool of proteins extracted by this method can be viewed more broadly as a soil health indicator that reflects the primary pool of organically bound N in soil and thus as potentially available organic N. We provide a laboratory protocol that details autoclaving soil in a neutral sodium citrate buffer solution followed by clarification and protein quantification steps.

Experimental Diabetes Alters the Morphology and Nano-Structure of the Achilles Tendon

Although of several studies that associate chronic hyperglycemia with tendinopathy, the connection between morphometric changes as witnessed by magnetic resonance (MR) images, nanostructural changes, and inflammatory markers have not yet been fully established. Therefore, the present study has as a hypothesis that the Achilles tendons of rats with diabetes mellitus (DM) exhibit structural changes. The animals were randomly divided into two experimental groups: Control Group (n = 06) injected with a vehicle (sodium citrate buffer solution) and Diabetic Group (n = 06) consisting of rats submitted to intraperitoneal administration of streptozotocin. MR was performed 24 days after the induction of diabetes and images were used for morphometry using ImageJ software. Morphology of the collagen fibers within tendons was examined using Atomic Force microscopy (AFM). An increase in the dimension of the coronal plane area was observed in the diabetic group (8.583 ± 0.646 mm2/100g) when compared to the control group (4.823 ± 0.267 mm2/100g) resulting in a significant difference (p = 0.003) upon evaluating the Achilles tendons. Similarly, our analysis found an increase in the size of the transverse section area in the diabetic group (1.328 ± 0.103 mm2/100g) in comparison to the control group (0.940 ± 0.01 mm2/100g) p = 0.021. The tendons of the diabetic group showed great irregularity in fiber bundles, including modified grain direction and jagged junctions and deformities in the form of collagen fibrils bulges. Despite the morphological changes observed in the Achilles tendon of diabetic animals, IL1 and TNF-α did not change. Our results suggest that DM promotes changes to the Achilles tendon with important structural modifications as seen by MR and AFM, excluding major inflammatory changes.

Expression and effect of proline hydroxylase domain 2 in retina of diabetic rats.

To observe the expression of proline hydroxylase domain 2 (PHD2) in the retina of diabetic rats and investigate the relationship between PHD2 and relevant intraocular vascular proliferation factors. Sixty male specific pathogen free (SPF) Sprague-Dawley (SD) rats were randomly divided into two groups: the diabetic group and the control group. The rats in the diabetic group were intraperitoneally injected with 60 mg/kg (0.60 mL/100g) of streptozotocin to induce a diabetic rat model. The rats in the control group were injected with an equal volume of sodium citrate buffer solution by the same method. Hematoxylin-eosin (HE) staining and immumofluorescence (IF) method were adopted to observe the pathological changes of retinal tissues and the expression of PHD2, glial fibrillary acidic protein (GFAP), vascular endothelial growth factor (VEGF) by 8wk. RT-PCR method was applied to detect the expressions of mRNA of PHD2, VEGF and GFAP. The relationship between PHD2 and other vascular proliferation factors was analyzed. HE staining showed that there was the retinal tissue edema in the diabetic group, and the arrangement was in disorder, and proliferation could be seen. IF staining: in the retina of normal rats, PHD2 was not expressed, GFAP and VEGF were mainly expressed in astrocytes; while in the diabetic rats, PHD2, GFAP and VEGF staining showed strong positivity in all retinal layers, mainly in neurogliocytes. PHD2 was co-expressed with VEGF and GFAP. The mRNA expression levels of PHD2, GFAP and VEGF in the diabetic group were obviously higher than that in the control group,respectively 1.83 times, 1.75 times and 2.08 times. The difference had statistical significance (P<0.01). The high expression of PHD2 in the retina of early-stage diabetic rats might result from secretion of neurogliocytes induced by local high-concentration blood glucose, thus promoting the expression of VEGF and GFAP. PHD2 plays an important role during the occurrence of diabetic retinopathy.

Effects of San-huang-sheng-fu oil on peripheral circulatory disorders and foot ulcers in diabetic rats and the mechanisms

Effects of San-huang-sheng-fu oil on peripheral circulatory disorders and foot ulcers in diabetic rats and the mechanisms

The potential beneficial effects of ethyl pyruvate on diabetic nephropathy: an experimental and ultrastructural study.

Oxidative stress is one of the main causes of diabetic nephropathy, which is a complication of diabetes mellitus (DM). The aim of this study was to investigate the possible role of ethyl pyruvate (EP) in streptozotocin-induced diabetic rats' kidney. Four groups (n = 8) of male Wistar albino rats were used as follows: control group rats received only sodium citrate buffer solution intraperitoneally (ip). The EP group was given 50 mg/kg EP ip. In the DM group, diabetes was induced by streptozotocin. The DM + EP group received 50 mg/kg EP ip. All animals received daily treatment for 14 days, and at the end of the study the kidneys were removed: the left kidney of the rats was used for malondialdehyde (MDA) analysis and the right kidney for histological examination. There was normal appearance of the kidney tissues in the control and the EP-administered groups. In the DM group, there was evident basement membrane thickening and enlargement of mesangial matrix; swelling in some tubular epithelial cells was also noticeable. In the DM+EP administered group, nearly the same appearance as the control group and relative thickening in the glomerular basal membrane were observed. The antioxidant effect of ethyl pyruvate improved the renal structures in the DM + EP group.

Evaluation of semen quality brought from Kundasale as replacement of locally produced semen for artificial insemination in Jaffna Peninsula, Sri Lanka

Artificial Insemination (AI) with frozen semen has been proved as the most potent method for rapid genetic improvement in domestic animals. While the use of AI with fresh semen is limited by the restricted period of sperm viability, this limitation may be overcome by the storage of frozen semen. Recently AI center of Thirunelvely is being advised to use the deep-frozen semen processed from Kundasale of Central Province (CP) for AI purposes. Thus the present study was undertaken to compare the quality of locally produced stored semen (LPS) and semen brought from Kundasale in deep-frozen condition (KDFS) by assessing the viability of them as the prominent factor that determine the successful of AI service . A batch of LPS and KDFS was obtained from the AI center at Thirunelvely. LPS was diluted with 2.9% sodium citrate buffer solution to evaluate the individual progressive motility and sperm velocity, sperm morphology, and acrosome integrity. Sperm smear was prepared by using 1% eosin and 0.75% Giemsa stain to identify intact and reacted acrosome and sperm abnormalities respectively. Thawed semen was also assessed for motility examination, percentage of intact acrosome, viability and morphology. Paired‘t’ test was performed to compare the means of the viability of LPS and KDFS (P Ving. Journal of Science 2012, Vol. 11, No. 1, 19-25

Determination of total arsenic and arsenic(III) in phosphate fertilizers by hydride generation atomic absorption spectrometry after ultrasound-assisted extraction based on a control acid media.

An ultrasound-assisted extraction procedure was developed for determination of inorganic arsenic (As) in phosphate fertilizer by hydride generation atomic absorption spectrometry. The variables that affect the hydride generation step were optimized, including the reducer, acid, sample flow rate, and concentrations of the acid and reducer. The determination of As(lll) was performed through the simple control of solution pH with a 0.5 M citric acid-sodium citrate buffer solution at pH 4.5, and total As was determined after a pre-reduction reaction with 1.0% (w/v) thiourea. Ultrasound-assisted acid extraction was performed, and the parameters sonication time and acid and Triton X-114 concentrations were optimized using a 23 factorial design and central composite design. LODs for As(lll) and total As were 0.029 and 0.022 microg/L, respectively. The accuracy of the method was confirmed with certified reference materials. The method was successfully applied in the determination of inorganic As in phosphate fertilizer samples.

Study on Enzymatic Degradation of Cornstalk in Ionic Liquid

The influence of reaction conditions on the enzymatic degradation of cornstalk in the system of 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) was investigated. The optimum condition was as follows: 5 g 4 wt% cornstalk in ionic liquid solution, 3.64 mL pH 5 citric acid–sodium citrate buffer solution, the concentration of cornstalk 55 mg/mL, the ratio of enzyme and cornstalk 0.5 mL/g, reaction temperature 55 °C and reaction time 30 h. Under the optimum condition, the rate of enzymatic degradation was 96.6 %, and was 2.1 times quicker than under the conventional condition. The changes of the molecular structure of cornstalk dissolved in [EMIM]OAc were detected by FT-IR and SEM. It was also found that ionic liquid [EMIM]OAc had good reusability.

The expression of opticin in vitreous body and retina of diabetes mellitus rats

Background: Diabetic retinopathy is a common complication of diabetes mellitus. Opcitin is a glycoprotein present in the vitreous body. Its role in diabetic retinopathy needs to be further defined. Objective: Investigate and compare the mRNA and protein levels of opticin in vitreous body and retina in normal and diabetic rats. Methods: Twenty-four male Sprague-Dawley (SD) rats were randomly divided into two groups (12/group), a streptozocin-induced diabetes (STZ) group and a control group. In the STZ group, 1% sterile STZ solution was injected into the rats intraperitonally (60mg/kg). An equal volume of sodium citrate buffer solution was administrated in the rats from the control group. The rats were sacrificed one month after various treatments. The eye bodies of three rats from each group were removed and fixed with 4% paraformaldehydeion for the following pathological analysis. Meanwhile, the vitreous bodies and retina of the other nine rats from each group were removed for the real-time PCR, immunohistochemistry, and western blot assays. Results: The mRNA level of opticin in the vitreous body of diabetes mellitus (DM) rats was 5.66% of that of the control ones (p Conclusions: The opticin expression in vitreous body and retina of diabetes rats was significantly decreased or even disappeared, which may suggest a key role of opticin in the development of diabetic retinopathy. Keywords: Diabetic retinopathy, opticin, rat

Absorption of Sulphur Dioxide with Sodium Citrate Buffer Solution in a Rotating Packed Bed

Absorption of SO 2 from a SO 2/air mixture with sodium citrate buffer solution was investigated using a rotating packed bed (RPB) in laboratory scale. The effects of operating parameters, such as the rotation speed of RPB, liquid-gas ratio, inlet gas flow rate, inlet concentration of SO 2 in flue gas, sodium citrate buffer concentration and initial pH of absorption solution, on the SO 2 concentration in the absorption solution or removal efficiency of SO 2 were examined. Incremental rate of sulfate radical ions in the absorption solution was also examined. Experimental results indicate that the efficiency of this regenerative process will be improved by using RPB under appropriate operating conditions, and the generation of SO 2− 4 will be restrained in the process in RPB.

Expression of the Stem Cell Markers Nestin and CD133 on Circulating Melanoma Cells

Different molecular markers have been identified for melanoma-initiating cells including CD133 and nestin. Assuming that metastasis requires a dissemination of tumor-initiating cells, presence of circulating tumor-initiating cells should be associated with worse patient outcome. In this study, 20 ml blood was collected from 32 consecutive patients affected by metastatic melanoma and blood was enriched for circulating melanoma cells (CMCs) by CD45 depletion of the non-melanoma cell fraction. Multiparameter cytometry was carried out to co-stain with combinations of CD133 and nestin (NES). Six tissue samples from metastatic lesions of six different patients were stained with the same antibodies by immunohistochemistry. Percentage of NES-positive CMCs correlated with tumor burden and number of metastatic sites. Cox regression analysis revealed levels of lactate dehydrogenase (LDH; hazard ratio: 12.8 (1.35-121.5); P=0.02), number of metastatic sites (hazard ratio 3.87 (1.66-9.03); P=0.02), tumor burden (hazard ratio 5.72 (1.57-20.9); P=0.01), and percentage of NES-expressing CMCs ≥ 35% (hazard ratio 5.73 (1.66-19.7); P=0.006) to be factors related to shorter overall survival. CD133- and NES-expression profiles on CMCs were similar to matched metastatic tissue. These findings show that CMCs expressed stem cell-associated markers NES and CD133. Higher expression of NES on CMCs might represent an index of poor prognosis.

High-performance liquid chromatography with post-column 2,2′-diphenyl-1-picrylhydrazyl radical scavenging assay: Methodological considerations and application to complex samples

An improved post-column 2,2′-diphenyl-1-picrylhydrazyl (DPPH ) radical scavenging assay for the screening of antioxidants in complex matrices was developed. Experimental parameters believed to be influential to DPPH response were studied in a univariate approach. Optimum conditions were found to be: 5 × 10 −5 M DPPH reagent prepared in a 75% methanol: 25% 40 mM citric acid–sodium citrate buffer (pH 6) solution, degassed with nitrogen; reaction coil of 2 m × 0.25 mm i.d. PEEK tubing; detection at 521 nm; analysis at room temperature. The analytical utility of this protocol was evaluated by screening for antioxidants in thyme and green tea, in comparison with two commonly employed methodologies.

Amperometric sensor for hydrogen peroxide based on poly(aniline- co- p-aminophenol)

It was found that the poly(aniline- co- p-aminophenol) film can effectively catalyze the oxidation of hydrogen peroxide in a sodium citrate buffer solution with pH 5.0. Here, we applied the copolymer to the construction of an efficient electrochemical sensor to determine the concentration of hydrogen peroxide. The sensor exhibited an excellent electrocatalytic activity toward the oxidation of H 2O 2, and the interferences of ascorbic acid and phenol were completely avoided. Unlike the inherent instability of enzyme, the poly(aniline- co- p-aminophenol) film-based sensor showed an outstanding stability.

Acid Phosphatase Assay with a Wireless Magnetoelastic Biosensor

A wireless remote‐query disposable magnetoelastic biosensor is developed for the assay of acid phosphatase (ACP). The sensor was fabricated by applying a layer of pH‐sensitive polymer to a magnetoelastic ribbon and, on top of it, a sensing film containing bovine serum albumin and adenosine‐5′‐monophosphate (5′‐AMP), the substrate of ACP. In response to an externally applied time‐varying magnetic field, the magnetoelastic sensor mechanically vibrates at a characteristic frequency that is inversely dependent on the mass of the attached film. Because the magnetoelastic sensor is magnetostrictive, the mechanical vibrations of the sensor launch magnetic flux that can be detected remotely from the sensor using a pick‐up coil. The ACP‐catalyzed hydrolysis of 5′‐AMP decreases the solution pH, resulting in the polymer shrinking and, consequently, the resonance frequency of the magnetoelastic sensor increasing. The experimental condition was optimized to be 37°C, in 2.5 mM sodium citrate buffer solution (pH 6.5). Using citrate as buffer can enhance the ACP activity, partly offsetting the effect of the buffer capacity on the sensitivity. The kinetic parameter were measured to be: 1.64×10–3 M (Michaelis constant) and 130 Hz/min (maximum initial rate). This work provides a remote enzymatic assay of ACP. The relative standard deviation in the measurements of six sensors in parallel is 3.4%. The proposed sensor can determine 0.2∼1.2 U/ml of ACP.