Preparation and Characterization of Simvastatin-Loaded PCL/PEG Nanofiber Membranes for Drug Sustained Release.

Simvastatin (SIM) particles are liposoluble drugs with large particle sizes, resulting in poor compatibility with electrospun polycaprolactone (PCL)/polyethylene glycol (PEG) nanofibers, so that part of them will be exposed to the electrospun nanofiber surface, which is easy to cause the burst release of drugs. Therefore, in this paper, stearic acid (SA) with good biocompatibility was innovatively added to increase the dispersion uniformity of SIM in the spinning solution, thus improving the performances of SIM-loaded PCL/PEG nanofiber membranes (NFMs). Accordingly, the effects of SA addition on the morphologies, mechanical properties, wettability, and drug release properties of the SIM-loaded NFMs were studied. The results showed that after SIM was dissolved in SA solution, the particle size of SIM was significantly reduced and could be evenly dispersed in the polymer spinning solution, thus obtaining the SIM-loaded composite NFMs with the best morphology and performance.

[Effect of fluidized bed technology on micromeritics properties of Leonurus Herba extract].

Based on different binders, the Leonurus Herba extract powders were fluidized and modified. The physical properties such as hygroscopicity, flowability, filling property and compression property were studied by various micromeritics methods before and after modification. The results showed that the physical properties of Leonurus Herba extract were close to those of microcrystalline cellulose, and its comprehensive flow index was between 61-75. Fluidization process can improve hygroscopicity, so the moisture absorption indexes of the samples were significantly lower than those of the original Leonurus Herba extract samples. With the plastic constant, compression ratio and yield stress, Heckel equation and Kawakita equation as the the investigation indicators, results showed that fluidization process based on binder water was superior to other methods in increasing the compressibility of the extracts. In low and medium pressure, the fluidized and modified extract can form the tablets with a certain strength. Fluidized transformation had a greater influence on the properties of original Leonurus Herba extracts, which was instructive to guide significance for the surface modification of pharmaceutical powders and provide the basis for the development of extract tablet.

Water-stable three-dimensional ultrafine fibrous scaffolds from keratin for cartilage tissue engineering.

Intrinsically water-stable scaffolds composed of ultrafine keratin fibers oriented randomly and evenly in three dimensions were electrospun for cartilage tissue engineering. Keratin has been recognized as a biomaterial that could substantially support the growth and development of multiple cell lines. Besides, three-dimensional (3D) ultrafine fibrous structures were preferred in tissue engineering due to their structural similarity to native extracellular matrices in soft tissues. Recently, we have developed a nontraditional approach to developing 3D fibrous scaffolds from alcohol-soluble corn protein, zein, and verified their structural advantages in tissue engineering. However, keratin with highly cross-linked molecular structures could not be readily dissolved in common solvents for fiber spinning, which required the remarkable drawability of solution. So far, 3D fibrous scaffolds from pure keratin for biomedical applications have not been reported. In this research, the highly cross-linked keratin from chicken feathers was de-cross-linked and disentangled into linear and aligned molecules with preserved molecular weights, forming highly stretchable spinning dope. The solution was readily electrospun into scaffolds with ultrafine keratin fibers oriented randomly in three dimensions. Due to the highly cross-linked molecular structures, keratin scaffolds showed intrinsic water stability. Adipose-derived mesenchymal stem cells could penetrate much deeper, proliferate, and chondrogenically differentiate remarkably better on the 3D keratin scaffolds than on 2D PLA fibrous scaffolds, 3D soy protein fibrous scaffolds, or 3D commercial nonfibrous scaffolds. In summary, the electrospun 3D ultrafine fibrous scaffolds from keratin could be promising candidates for cartilage tissue engineering.

Batch preparation and characterization of zein-based beaded nanofiber membranes for active food packaging.

Active packaging can efficiently enhance the shelf life of food, realizing the encapsulation and effective release of antibacterial agents and antioxidants. Zein is a natural protein derived from corn, widely used in food packaging. In this work, zein-based nanofiber membranes (NFMs) with beaded structures for food packaging were fabricated in batch using a self-made free surface electrospinning. The characteristics of NFMs were investigated in terms of their morphologies, structures and properties. The results illustrated that the antioxidant activity of NFMs was significantly improved after adding licorice extracts. Moreover, after adding the eugenol to the zein/licorice extract NFMs, zein/licorice extract/eugenol (ZLE) NFM had outstanding antibacterial activities against Staphylococcus aureus and Escherichia coli, which effectively prolonged the shelf-life of the grapes when it was used to package grapes. It proved that ZLE NFM had great potential in food packaging applications.

Preparation of chitosan/citral forward osmosis membrane via Schiff base reaction with enhanced anti-bacterial properties.

In this study, hydrogels generated by the Schiff base reaction between citral and chitosan (CS) were used for the first time to improve the anti-bacterial property of forward osmosis (FO) membranes. The composite membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Water contact angle (WCA), Zeta potential and confocal laser scanning microscopic (CLSM). In the FO filtration experiment, the membrane performance of TFC-1 with 1 M sodium chloride solution as the draw solution and deionized water as the feed solution was the best, with the water flux of 25.54 ± 0.7 L m-2 h-1 and the reverse salt flux of 4.7 ± 0.4 g m-2 h-1. Although the hydrogel coating produced a certain hydraulic resistance, the flux of the modified membrane was only reduced by about 8%, compared with the unmodified membrane. However, the anti-bacterial property (Pseudomonas aeruginosa) and anti-fouling properties (bovine serum protein and lysozyme protein) of the modified membranes were improved, showing good antibacterial properties (99%) and flux recovery rate (over 90%). The modified method has the advantages of easy access to raw materials, simple operation and no risk of secondary pollution, which can effectively reduce the cost of chemical cleaning and extend the service life of the membrane. The modification of membrane by chitosan-based hydrogel is a promising option in the field of membrane anti-bacteria.

High-throughput fabrication of silk fibroin/hydroxypropyl methylcellulose (SF/HPMC) nanofibrous scaffolds for skin tissue engineering.

Silk fibroin (SF) is a natural macromolecule material with good biocompatibility, which can be used to prepare a variety of biological materials. In this study, hydroxypropyl methylcellulose (HPMC) was applied to improve the properties of SF nanofibrous scaffolds (NFS) for skin tissue engineering applications. SF/HPMC NFS with varying weight ratios of SF: HPMC were prepared in batches by a modified free surface electrospinning. The effects of the varying weight ratio of SF: HPMC on the morphology, property and yield of SF/HPMC NFS were investigated. The results revealed that with the increase of HPMC contents, the hydrophilicity of SF/HPMC NFS would be improved, but the yield of that would decrease. Considering its effects on the morphology, property and yield of SF/HPMC NFS, the optimal weight ratio of SF: HPMC was 7:1. And SF/HPMC NFS with the weight ratio of 7:1 (SF/HPMC-7:1 NFS) had good mechanical property, hydrophilicity, porosity, swelling property and water vapor transmission rate (WVTR). In addition, the viability test results of human umbilical vein endothelial cells demonstrated that SF/HPMC-7:1 NFS maintained excellent biocompatibility for cell adhesion and proliferation.

Batch preparation of electrospun polycaprolactone/chitosan/aloe vera blended nanofiber membranes for novel wound dressing.

At present, more and more attention has been paid to the development of active wound dressings. Chitosan, a kind of carbohydrate polymer with good biocompatibility, is widely used in the field of wound dressings. In this study, a slopeing free surface electrospinning (SFSE) device was presented to prepare large quantities of polycaprolactone/chitosan/aloe vera (PCL/CS/AV) nanofiber membranes (NFMs) for antibacterial wound dressing. And the morphologies of PCL/CS/AV NFMs with varying weight ratios of PCL:CS:AV were studied using SEM, and the optimal weight ratio of 5:3:2 was determined for better wound dressings. Then the structure, wetting property and yield of the PCL/CS/AV NFMs with the optimal weight ratio were investigated, and the effects of the addition of AV on the antibacterial performance and the biocompatibility of NFMs was studied. In addition, the preparation mechanism of SFSE was researched by simulating the electric field distribution using Maxwell 3D due to the important role of the electric field in the SFSE process. The simulation analyses of electric fields agreed with the experimental data. The results illustrated SFSE could prepare high quality PCL/CS/AV NFMs in batches, and its yield of PCL/CS/AV NFMs was 10 times more than the single-needle ES, and the fabricated NFMs showed excellent antibacterial performance and biocompatibility, which made them suitable for wound dressings.

Chiral stationary phase based on cellulose derivative coated polymer microspheres and its separation performance.

Chiral stationary phases (CSPs) have always been research hotspot in enantiomer separation. Currently, most of the CSPs are based on silica platform. In this research, monodisperse, porous glycidyl methacrylate-divinylbenzene copolymer particles (poly(GMA-DVB)) were designed and prepared. Then the GMA was further reacted with ethylenediamine to introduce amino groups onto the polymer, which provide anchoring sites for cellulose derivatives. Herein, Cellulose-tris (3,5-dimethylphenylcarbamate) (CDMPC) was successfully coated onto the polymer microspheres, achieving a stable and successful CSP. The porous structure and the surface moieties of the CSPs were studied in detail. The chromatographic separation was optimized. Hexaconazole,methyl DL-mandelate,benzoin and tebuconazole have been successfully separated on the CSP column, with column efficiency as high as 10,200 plates/m, which is comparable with some silica-based CSPs. The research has indicated that the poly(GMA-DVB) is a promising candidate for constructing CSPs for chiral separation.

First-line therapy for chronic graft-versus-host disease that includes low-dose methotrexate is associated with a high response rate.

We report the results of low-dose methotrexate (MTX) as first-line therapy mostly in combination with other immunosuppressive agents in patients with chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Between November 2001 and March 2008, 86 patients with cGVHD after allo-HSCT received low-dose MTX therapy until a complete or partial response (CR, PR) was achieved, or until treatment failure or intolerable side effects were found. The median time from HSCT to the start of MTX was 154 (range: 80-993) days. The median number of MTX administrations was 4 (range: 2-18). The overall response rate among all enrolled patients was 83% (71 of 86 patients). The response rate for GVHD involving various organs was 90% (45 of 50) in the skin, 75% (39 of 52) in the liver, 42% (5 of 12) in the mouth, 3 of 7 in the eye, and 2 of 2 in the gut. In addition, MTX treatment allowed for a significant reduction in the prednisone dosage (median 90%) from 20 (2.5-100) mg at the start of MTX administration to 5 (0-30) mg 1 month after MTX was last used. Multivariate analysis showed that the only significant factor related to higher CR rate was sole organ involvement (P = .007). Grade 3 toxicities occurred in only 3 patients presenting cytopenias or oral mucositis. From this analysis, MTX appears to be a well-tolerated, effective, and inexpensive agent when used as a first-line treatment in combination with other immunosuppressive agents for cGVHD, especially for skin or sole organ involvement without concomitant thrombocytopenia.

A Novel Human Papillomavirus 16 L1 Pentamer-Loaded Hybrid Particles Vaccine System: Influence of Size on Immune Responses.

Cervical cancer remains the second-most prevalent female malignancy around the world, leading to a great majority of cancer-related mortality that occurs mainly in developing countries. Developing an effective and low-cost vaccine against human papillomavirus (HPV) infection, especially in medically underfunded areas, is urgent. Compared with vaccines based on HPV L1 viruslike particles (VLPs) in the market, recombinant HPV L1 pentamer expressed in Escherichia coli represents a promising and potentially cost-effective vaccine for preventing HPV infection. Hybrid particles comprising a polymer core and lipid shell have shown great potential compared to conventional aluminum salts adjuvant and is urgently needed for HPV L1 pentamer vaccines. It is well-reported that particle sizes are crucial in regulating immune responses. Nevertheless, reports on the relationship between the particulate size and the resultant immune response have been in conflict, and there is no answer to how the size of particles regulates specific immune response for HPV L1 pentamer-based candidate vaccines. Here, we fabricated HPV 16 L1 pentamer-loaded poly(d,l-lactide- co-glycolide) (PLGA)/lecithin hybrid particles with uniform sizes (0.3, 1, and 3 µm) and investigated the particle size effects on antigen release, activation of lymphocytes, dendritic cells (DCs) activation and maturation, follicular helper CD4+ T (TFH) cells differentiation, and release of pro-inflammatory cytokines and chemokines. Compared with the other particle sizes, 1 µm particles induced more powerful antibody protection and yielded more persistent antibody responses, as well as more heightened anamnestic responses upon repeat vaccination. The superior immune responses might be attributed to sustainable antigen release and robust antigen uptake and transport and then further promoted a series of cascade reactions, including enhanced DCs maturation, increased lymphocytes activation, and augmented TFH cells differentiation in draining lymph nodes (DLNs). Here, a powerful and economical platform for HPV vaccine and a comprehensive understanding of particle size effect on immune responses for HPV L1 pentamer-based candidate vaccines are provided.

Cellulose nanocrystal-reinforced keratin bioadsorbent for effective removal of dyes from aqueous solution.

High-efficiency and recyclable three-dimensional bioadsorbents were prepared by incorporating cellulose nanocrystal (CNC) as reinforcements in keratin sponge matrix to remove dyes from aqueous solution. Adsorption performance of dyes by CNC-reinforced keratin bioadsorbent was improved significantly as a result of adding CNC as filler. Batch adsorption results showed that the adsorption capacities for Reactive Black 5 and Direct Red 80 by the bioadsorbent were 1201 and 1070mgg-1, respectively. The isotherms and kinetics for adsorption of both dyes on bioadsorbent followed the Langmuir isotherm model and pseudo-second order model, respectively. Desorption and regeneration experiments showed that the removal efficiencies of the bioadsorbent for both dyes could remain above 80% at the fifth recycling cycles. Moreover, the bioadsorbent possessed excellent packed-bed column operation performance. Those results suggested that the adsorbent could be considered as a high-performance and promising candidate for dye wastewater treatment.

Study on the immobilization of anti-IgG on Au-colloid modified gold electrode via potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques.

The immobilization of anti-IgG on Au-colloid modified gold electrodes has been investigated. A cleaned gold electrode was first immersed in a mercaptoethylamine (AET) solution, and then gold nanoparticles were chemisorbed onto the thiol groups of the mercaptoethylamine. Finally, anti-IgG was adsorbed onto the surface of the gold nanoparticles. Potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques were used to investigate the immobilization of anti-IgG on Au colloids. In the impedance spectroscopic study, an obvious difference of the electron transfer resistance between the Au-colloid modified electrode and the bare gold electrode was observed. The cyclic voltammogram tends to be more irreversible with increased anti-IgG concentration. Using the potentiometric immunosensor, the proposed technique is based on that the specific agglutination of antibody-coated gold nanoparticles, averaging 16 nm in diameter, in the presence of the corresponding antigen causes a potential change that is monitored by a potentiometry. It is found that the developed immunoagglutination assay system is sensitive to the concentration of IgG antigen as low as 12 ng mL(-1). Experimental results showed that the developed technique is in satisfactory agreement with the ELISA method, and that gold nanoparticles can be used as a biocompatible matrix for antibody or antigen immobilization.

Potentiometric membrane electrode for salicylate based on an organotin complex with a salicylal Schiff base of amino acid.

A novel salicylate-selective electrode based on an organotin complex with a salicylal Schiff base of amino acid salicylaldehydeaminoacid-di-n-butyl-Sn(IV) [Sn(IV)-SAADB] as ionophore is described, which exhibits high selectivity for salicylate over many other common anions with an anti-Hofmeister selectivity sequence: Sal- >> PhCOO- > SCN- > Cl04- > I- > NO3- > NO2- > Br- > Cl- > CH3COO-. The electrode, based on Sn(IV)-SAADB, with a 30.44 wt% PVC, a 65.45 wt% plasticizer (dioctyl phthalate, DOP), a 3.81 wt% ionophore and a 0.3 wt% anionic additive is linear in 6.0 x 10(-6) - 1.0 x 10(-1) mol l(-1) with a detection limit of 2.0 x 10(-6) mol l(-1) and a slope of 62.0 +/- 1.2 mV/decade of salicylate concentration in a phosphate buffer solution of pH 5.5 at 25 degrees C. The influence on the electrode performances by lipophilic charged additives was studied, and the possible response mechanism was investigated by UV spectra. The electrode was applied to medicine analysis and the result obtained has been satisfactory.

[Methotrexate for treatment of graft versus host disease after allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To evaluate the efficacy and safety of low-dose methotrexate in patients with graft versus host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (Allo-HSCT). METHODS: Thirty-one patients with minor or moderate grade acute GVHD (aGVHD), chronic GVHD (cGVHD) or GVHD post donor lymphocyte infusion (post-DLI GVHD) after Allo-HSCT received intravenously administrated methotrexate at a dose of 5 or 10mg every 5 to 7 days until achieving complete or partial responses, treatment failure or intolerable side effects. RESULTS: The overall response rate was 93.8% (15/16 patients) in patients with aGVHD, 75% (12/16 patients) in patients with cGVHD and 100% (2/2 in patients) with post-DLI GVHD. The response rate for GVHD involving organs was 100% in skin, 60% in gut, 71% in liver, 75% in mouth and 100% in eyes. Side effects were minor. During the therapy, the other immunosuppressive agents were reduced. CONCLUSION: Short-term low-dose methotrexate is a tolerable and effective regimen for patients with minor or moderate grade aGVHD, cGVHD or post-DLI GVHD after Allo-HSCT.

Development and characterization of thermoplastic films from sorghum distillers dried grains grafted with various methacrylates.

Distillers Dried Grains (DDG) obtained during production of ethanol from grain sorghum were grafted with methacrylates and compression molded into films with good dry and wet tensile properties. Since sorghum DDG contains up to 45% proteins that are indigestible by animals, it is necessary to find alternative applications to make sorghum ethanol economically competitive. In this research, sorghum DDG was grafted with methyl, ethyl, and butyl methacrylates, the grafted DDG was compression molded into films, and the properties of the grafted DDG and films were studied. At a grafting ratio of 40%, butyl methacrylate (BMA) grafted films had a strength of 4.8 MPa and elongation of 1.8% when dry and 3.1 MPa and 8.1% when wet, indicating that the films had good strength and wet stability. Films developed from grafted DDG show the potential to overcome the brittleness and poor water stability of biopolymer-based films and be useful for various applications.

Cytocompatible and water-stable camelina protein films for tissue engineering.

In this research, films with compressive strength and aqueous stability were developed from camelina protein (CP) for tissue engineering. Protein based scaffolds have poor mechanical properties and aqueous stability and generally require chemical or physical modifications to make them applicable for medical applications. However, these modifications such as crosslinking could reduce biocompatibility and/or degradability of the scaffolds. Using proteins that are inherently water-stable could avoid modifications and provide scaffolds with the desired properties. CP with a high degree of disulfide cross-linkage has the potential to provide water-stable biomaterials, but it is difficult to dissolve CP and develop scaffolds. In this study, a new method of dissolving highly cross-linked proteins that results in limited hydrolysis and preserves the protein backbone was developed to produce water-stable films from CP without any modification. Only 12 % weight loss of camelina films was observed after 7 days in phosphate buffer saline (PBS) at 37°C. NIH 3T3 fibroblasts could attach and proliferate better on camelina films than on citric acid cross-linked collagen films. Therefore, CP films have the potential to be used for tissue engineering, and this extraction-dissolution method can be used for developing biomedical materials from various water-stable plant proteins.

Enhanced brain delivery of lamotrigine with Pluronic(®) P123-based nanocarrier.

BACKGROUND: P-glycoprotein (P-gp) mediated drug efflux across the blood-brain barrier (BBB) is an important mechanism underlying poor brain penetration of certain antiepileptic drugs (AEDs). Nanomaterials, as drug carriers, can overcome P-gp activity and improve the targeted delivery of AEDs. However, their applications in the delivery of AEDs have not been adequately investigated. The objective of this study was to develop a nano-scale delivery system to improve the solubility and brain penetration of the antiepileptic drug lamotrigine (LTG). METHODS: LTG-loaded Pluronic(®) P123 (P123) polymeric micelles (P123/LTG) were prepared by thin-film hydration, and brain penetration capability of the nanocarrier was evaluated. RESULTS: The mean encapsulating efficiency for the optimized formulation was 98.07%; drug-loading was 5.63%, and particle size was 18.73 nm. The solubility of LTG in P123/LTG can increase to 2.17 mg/mL, making it available as a solution. The in vitro release of LTG from P123LTG presented a sustained-release property. Compared with free LTG, the LTG-incorporated micelles accumulated more in the brain at 0.5, 1, and 4 hours after intravenous administration in rats. Pretreatment with systemic verapamil increased the rapid brain penetration of free LTG but not P123/LTG. Incorporating another P-gp substrate (Rhodamine 123) into P123 micelles also showed higher efficiency in penetrating the BBB in vitro and in vivo. CONCLUSION: These results indicated that P123 micelles have the potential to overcome the activity of P-gp expressed on the BBB and therefore show potential for the targeted delivery of AEDs. Future studies are necessary to further evaluate the appropriateness of the nanocarrier to enhance the efficacy of AEDs.

A potentiometric chiral sensor for L-Phenylalanine based on crosslinked polymethylacrylic acid-polycarbazole hybrid molecularly imprinted polymer.

A novel chiral molecularly imprinted polymer (MIP) sensor for L-Phenylalanine has been developed, which is constructed by electrochemically driven cross-linking a pendant polymer precursor, poly[2-(N-carbazolyl)ethyl methacrylate-co-meth-acrylic acid]s (PCEMMAs). In this MIP sensing material, the recognition sites, the insulating polymethylacrylic acid (PMAA), were covalently bonded to the conducting polycarbazole which could be used as signal transfer interface between recognition layer and electrode. The mole ratio of copolymerizing monomers, 2-(N-carbazolyl) ethyl methacrylate:methylacrylic acid (CE:MAA), and the scanning cycles of electropolymerization were adjusted during the preparation of MIP sensing material. The optimized conditions, CE:MAA=3:2 and 20 scanning cycles, were obtained. And then the properties of MIP films were characterized by atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle. Open circuit potential-time technique was used to estimate the enantioselectivity of the MIP sensor. The results indicate that the promising sensor preferentially responses L-Phenylalanine (L-Phe) over D-Phenylalanine (D-Phe) with a selectivity coefficient K(D)(L)=5.75×10(-4) and the limit of detection (LOD) is 1.37µM, which reveals its good enantioselectivity and sensitivity.

Epidemiology of hand, foot, and mouth disease and genotype characterization of Enterovirus 71 in Jiangsu, China.

BACKGROUND: In the spring of 2008, an EV71-caused hand, foot, and mouth disease (HFMD) outbreak occurred in Fuyang city, Anhui Province, China. Jiangsu Province that borders Auhui to the east is presumed as a key station for the spread of EV71 to other regions of the Yangtze River Delta. OBJECTIVES: To investigate the HFMD prevalence in Zhenjiang city of Jiangsu from May 2008 to October 2009, and the epidemic origin of EV71 circulating in Jiangsu. STUDY DESIGN: During May 2008 and October 2009, a total of 6324 HFMD cases in Zhenjiang, Jiangsu, were investigated. Sixty throat specimens were randomly selected from different patients, and 28 nucleotide sequences of EV71 VP1 regions were successfully determined by RT-nested-PCR and sequencing. EV71 genotypes were characterized by phylogenetic analyses. RESULTS: The incidence rate of HFMD was highest in the period of March-July and in the 1-4 years old age groups. Intriguingly, there was a slight predominance for boys and for children living in rural areas in HFMD infection. Phylogenetic analyses indicated that all Jiangsu EV71 strains and most China strains belonged to subgenotype C4a. CONCLUSION: The C4a was the most prominent EV71 subgenotype circulating in China. Routine HFMD surveillance should be focused on the period of March-July, and more prevention efforts should be aimed at 1-4 years old children. Moreover, government efforts are urgently needed to improve public health condition and medical service quality in rural areas.

Chiral salen Mn(III) complex-based enantioselective potentiometric sensor for L-mandelic acid.

A new enantioselective potentiometric sensor containing chiral salen Mn(III) as the chiral selector was designed for the assay of L-mandelic acid (L-MA). Optimized membrane electrodes displayed linear dynamic range from 1x10(-5) to 1x10(-1) mol L(-1) with a detection limit of 7.2x10(-6) mol L(-1) and a Nernstian response of -58.1+/-0.5 mV decade(-1) towards L-MA within pH range 7.0-10.2. The potentiometric enantioselectivity coefficient (logK(L,D)(Pot)) of this sensor was -4.0, indicating that the chiral salen Mn(III) complex-based electrode exhibited fairly good discrimination toward L-MA over counter isomer D-MA. The mechanism of chiral recognition for L-MA is discussed by using HF/STO-3G calculation method simulation.