Polystyrene-co-maleic Anhydride Research Articles

Electrospun fibrous mats with conjugated tetraphenylethylene and mannose for sensitive turn-on fluorescent sensing of Escherichia coli.

A rapid and sensitive detection of microbes in water and biological fluids is a key requirement in water and food safety, environmental monitoring, and clinical diagnosis and treatment. In the current study, electrospun polystyrene-co-maleic anhydride (PSMA) fibers with conjugated mannose and tetraphenylethylene (TPE) were developed for Escherichia coli (E. coli) detection, taking advantage of the high grafting capabilities of ultrafine fibers and the highly porous structure of the fibrous mat to entrap bacterial cells. The specific binding between mannose grafts on PSMA fibers and FimH proteins from the fimbriae of E. coli led to an efficient "turn-on" profile of TPE due to the aggregation-induced emission (AIE) effect. Poly(ethylene glycol) diamine was used as hydrophilic tethers to increase the conformational mobility of mannose grafts, indicating a more sensitive change in the fluorescence intensity against bacteria concentrations, a lower fluorescence background of fibers without bacteria incubation, and a sufficient space for bacteria binding, compared with the use of hexamethylenediamine or poly(ethylene imine) as spacers for mannose grafting. The addition of bovine serum albumin, glucose, or both of them into bacteria suspensions showed no significant changes in the fluorescence intensity of fibrous mats, indicating the anti-interference capability against these proteins and saccharides. An equation was drafted of the fluorescence intensities of fibrous mats against E. coli concentrations ranging from 10(2) to 10(5) CFU/mL. The test strip format was established on mannose-conjugated PSMA fibers after exposure to E. coli of different concentrations, providing a potential tool with a visual sensitivity of bacteria concentrations as low as 10(2) CFU/mL in a matter of minutes. This strategy may offer a capacity to be expanded to exploit electrospun fibrous mats and other carbohydrate-cell interactions for bioanalysis and biosensing of pathogenic bacteria.

Multimeric immobilization of alcohol oxidase on electrospun fibers for valid tests of alcoholic saliva

An accurate quantitation of ethanol is of great importance in clinical and forensic analyses. In the current study, alcohol oxidase (AOX) from Pichia pastoris, a multimeric enzyme consisting of eight identical subunits, was immobilized on electrospun polystyrene-co-maleic anhydride (PSMA) fibers for valid tests of alcoholic saliva. Branched polyethyleneimine (PEI) was grafted on PSMA fibers with a density of 0.15nmol/cm2 as tethers to allow multipoint covalent binding of enzyme molecules through glutaraldehyde activation, and the secondary and tertiary amino groups of PEI could intensify the interactions with AOX subunits to stabilize the quaternary structure. PSMA-PEI-AOX fibers were less sensitive than free AOX to the incubation temperature and pH, and indicated no detectable subunit release from the immobilized AOX after boiling in the presence of sodium dodecyl sulfate (SDS) and 2-mercaptoethanol. Color strips were established on PSMA-PEI-AOX fibrous mats dyed with indigo Carmine after incubation into ethanol solutions of different concentrations. The color fading ratio remained no significant change after repeat tests for 9 cycles after immersion in 0.2 and 0.8mg/mL of alcoholic saliva. It was indicated that multipoint immobilization of the multimeric enzyme was essential to improve the enzyme stability by stabilizing both the quaternary structure of the enzyme and the structure of each individual subunit.

Modulation of cell responses by creating surface submicron topography and amine functionalities

The incorporation of biological function into synthetic polymers provides particular potential for advances in studying the complex interactions between biomolecules and materials. We developed a simple method to create polymer with submicron features on surface of polystyrene-co-maleic anhydride (PSMAA) using a combination of phase-separation and spin coating method. The nanostructured PSMAA which was rarely utilized as biomaterials was further functionalized by doping with dopamine or by treating with nitrogen containing plasma. This study demonstrated a straightforward method that the creation of topographical cues alone improves the biocompatibility of PSMAA thin film. The cell proliferation increased more significantly to ∼1.8- and 2.5-fold on dopamine blended and N2/H2 plasma treated PSMAA films when compared to that on the flat sample, respectively. The overall results showed that the integration of microenvironment and chemical functionalities into materials provide promising effects for promoting mammalian cell growth. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

Conductive quantum dot-encapsulated electrospun nanofibers from polystyrene and polystyrene-co-maleic anhydride copolymer blend as gas sensors

Electrospinning was employed to obtain uniformly distributed Cadmium Selenide (CdSe)/Zinc Sulfide (ZnS) core shell quantum dot (QD) encapsulated nanofibers in polymeric mixture of 4:1 ratio of polystyrene (PS) and polystyrene-co-maleic anhydride (PSMA). Fluorescence and scanning electron microscopy (SEM) measurements were used to evaluate the uniform size distribution and uniformity of PS–PSMA nanofibers with high aspect ratios. The introduction of QDs only into the PS–PSMA nanofibers induced electrical conductivity. They also showed a two to three fold increase in electrical conductivity in the presence of volatile organic compounds. The obtained quantum-dot nanofibers (Qd-NFs) were 600–650 nm thick, photostable for more than six months, and applicable for electrical conductance or gas-based sensing applications.

Development of a portable electronic nose based on chemical surface acoustic wave array with multiplexed oscillator and readout electronics

A portable electronic nose (E-nose) based on a novel chemical surface acoustic wave array with multiplexed oscillator and readout electronics was developed and tested. The sensor array was fabricated on a large K 2 128° YX-LiNbO 3 sensing substrate. On the surface of this substrate, an interdigital transducer (IDT) was made with a Cr/Au film as a metallic structure. The center frequency of the sensing chips was designed at 99.8 MHz. Seven polymers, poly-4-vinylphenol (P4VP), poly-vinylacetate (PVAc), poly-N-vinylpyrrolidone (PNVP), polyethyleneglycol (PEG), polystyrene (PS), polystyrene-co-maleic anhydride (PSMA), and polysulfone (PSu), were coated on the sensing area of Au surface between the center of the IDTs. The 2 × 2 non-continuous SAW array could be controlled by a multiplexing technique and sensor signals could be obtained by readout electronics with an 89C51 microprocessor. Five different organic vapors were adopted as samples to test the developed system. The frequency shifts (Δ f) were measured and the stable state was about 1 kHz. Two-way hierarchical clustering analysis was used to analyze the measured data. It showed that based on the analysis method, gases and polymers with similar chemical properties were grouped into the same family. The results suggest that the development of a portable E-nose and the applied analysis method are promising for practical applications of gas detection and recognition.

Self-cured polymers from non-drying oil

Pongamia glabra seed oil (PGSO) – a non-edible, non-drying oil; a sustainable resource has found application as alkyds, epoxies and polyesteramides in paints and coatings. Generally, PGSO based polymeric coatings are obtained by curing at elevated temperature. Efforts have been made to cure PGSO at room temperature by simple route modification. Self-cured Pongamia glabra oil based on polyesteramide (APGPEA) resin was synthesized by the reaction between Pongamia glabra oil modified fatty amide diol (HEPGA) with polystyrene co-maleic anhydride (SMA). After complete synthesis of APGPEA, phthalic anhydride modified polyesteramide (APGPEAPh) was synthesized in situ by a minor addition of phthalic anhydride (PA) to APGPEA in order to improve the performance of the latter. The effect of the SMA and PA introduction on properties of PGPEAPh film was also investigated. The physico-chemical characteristics of both resins were obtained by standard laboratory methods. The structural elucidation of these resins was carried out by FT-IR, 1H-NMR and 13C-NMR spectral techniques. The thermal behavior was studied by TGA. Curing was studied by DSC and FT-IR techniques. It was observed that APGPEA and APGPEAPh resins significantly improve the drying property in contrast to the previously reported polyesteramides cured at high temperature. Physico-mechanical and chemical/corrosion resistance tests of APGPEAPh coatings showed that the presence of phthalic anhydride in APGPEA enhanced the physico-mechanical and corrosion resistance considerably. The APGPEAPh resin appears to be sustainable aspirant biomaterials for anticorrosive surface coatings which may substitute polymers obtained from petroleum, potentially scarce resource.