In this work silica (SiO2) and sulfonic acid-functionalized silica (sul-SiO2) were synthesized by sol–gel method from tetraethoxysilane (TEOS) and 3-mercatopropyltrimethoxysilane (MPTMS) with various ratios between them. The synthesized materials were characterized by x-ray diffraction (XRD) for crystalline structure, Brunauer–Emmet–Teller (BET) specific surface area analysis, transmission electronic microscopy (TEM) and dynamic light scattering (DLS) for particle size analysis, and ion exchange capacity (IEC) for determining sulfur content in Sul-SiO2 materials. The initial results showed that the average particle size of amorphous SiO2 and Sul-SiO2 at different TEOS: MPTMS ratios are in narrow distribution with average diameter about 20–30 nm. The particle size of Sul-SiO2 is almost unaffected by the content of MPTMS while IEC depends strongly on it. Composite membranes of 60 μm thickness were successfully prepared from blending of poly(vinylidene fluoride) (PVDF) and synthesized amorphous SiO2. It was shown that the latter may be used as a reinforced phase for composite membrane electrolytes based on PVDF.

The bamboo fiber is a potential candidate for biomass and power source application. In this study, microfibrillated cellulose (MFC) is prepared from raw fibers of bamboo tree (Bambusa Blumeana J A & J H Schultes) by an alkali treatment at room temperature in association with a bleaching treatment followed by a sulfuric acid hydrolysis. Field-emission scanning electron microscopy (FESEM) images indicated that final products ranged from 20 to 40 nm in diameter. The chemical composition measurement and Fourier transform infrared (FTIR) spectroscopy showed that both hemicellulose and lignin are mostly removed in the MFC. The x-ray diffraction (XRD) results also show that MFC has crystallinity of more than 70%. The thermogravimetric analysis (TGA) curves revealed that cellulose microfibers have a two-step thermal decomposition behavior owing to the attachment of sulfated groups onto the cellulose surface in the hydrolysis process with sulfuric acid. The obtained MFCs may have potential applications in alternative power sources as biomass, in pharmaceutical and optical industries as additives, as well as in composite fields as a reinforcement phase.

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Although Escherichia coli (E. coli) is a commensalism organism in the intestine of humans and warm-blooded animals, it can be toxic at higher density and causes diseases, especially the highly toxic E. coli O157:H7. In this paper a quartz crystal microbalance (QCM) biosensor was developed for the detection of E. coli O157:H7 bacteria. The anti-E. coli O157:H7 antibodies were immobilized on a self-assembly monolayer (SAM) modified 5 MHz AT-cut quartz crystal resonator. The SAMs were activated with 16-mercaptopropanoic acid, in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and ester N-hydroxysuccinimide (NHS). The result of changing frequency due to the adsorption of E. coli O157:H7 was measured by the QCM biosensor system designed and fabricated by ICDREC-VNUHCM. This system gave good results in the range of 102–107 CFU mL−1 E. coli O157:H7. The time of bacteria E. coli O157:H7 detection in the sample was about 50 m. Besides, QCM biosensor from SAM method was comparable to protein A method-based piezoelectric immunosensor in terms of the amount of immobilized antibodies and detection sensitivity.

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