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Yingjuan H.,Key Laboratory of Food Colloids and Biotechnology | Ruiyi L.,National University of Ireland, Maynooth | Zaijun L.,Key Laboratory of Food Colloids and Biotechnology | Zaijun L.,Jiangnan University | And 4 more authors.
Analytical Methods | Year: 2013

Peanut allergen is a growing food safety problem because peanut seeds are increasingly used in the food industry. Here we report a resonance light scattering (RLS) method for the detection of peanut allergen-Ara h 1 with gold nanorods (GNRs) prepared by an improved synthesis through the use of an anionic surfactant sodium dodecyl benzene sulfonate (SDBS) additive. The study demonstrated that the use of SDBS allows the reduction of hexadecyltrimethylammonium bromide to 0.05 M as opposed to 0.1 M in well-established protocols, and improves the monodispersity and stability of the GNRs. Moreover, a probe DNA modified with a thiol at its 5′ end and a biotin at its 3′ end was attached to the surface of the as-synthesized GNRs to form a stem-loop structure by self-assembly through facile gold-thiol affinity. The stem-loop probe was "closed" when the target DNA was absent; however, the hybridization of the target DNA with the probe DNA induces the conformational change to "open", along with the biotin at its 3′ end moving away from the GNR surface, which results in an increase of the RLS intensity of the GNRs. The detection limit was found to be 0.06 pM with the linear response ranging from 0.0002 to 50 nM. The present method offers the improvement of rapidity, sensitivity and selectivity compared with other reported methods. It has been successfully applied for the determination of peanut allergen-Ara h 1 in peanut milk beverage. © 2013 The Royal Society of Chemistry. Source

Ruiyi L.,Jiangnan University | Jiajia W.,Jiangnan University | Ling L.,Jiangnan University | Zaijun L.,Jiangnan University | Zaijun L.,Key Laboratory of Food Colloids and Biotechnology
Microchimica Acta | Year: 2016

The paper reports on the synthesis of a composite consisting of thionin-functionalized multiple graphene aerogel and gold nanostars (termed TF-MGA/GNSs). The composite displays an enhanced electrochemical performance compared to the classical graphene aerogel. The performance can be further improved by increasing number of the graphene oxide gelation cycles. The composite was deposited on a glassy carbon electrode to obtain a biosensor for the direct detection of dsDNA. The interaction of thionin with dsDNA causes a specific electrochemical response, best at a working voltage of −228 mV (vs. Ag/AgCl). The enhanced electrocatalytic activity of the composite strongly improves sensitivity. The differential pulse voltammetric signal linearly decreases with increasing dsDNA concentration in the range from 100 fg · mL−1 to 10 ng · mL−1, and the detection limit is 39 fg · mL−1 (at an S/N ratio of 3). The method is sensitive, selective and rapid. It was successfully applied to the detection of circulating free DNA in human serum. The study also provides an attractive approach towards graphene aerogel-based materials to meet the needs of nanoelectronics for molecule diagnosis, bioanalysis and catalysis. [Figure not available: see fulltext.] © 2016 Springer-Verlag Wien Source

Tao Y.,Jiangnan University | Ruiyi L.,Jiangnan University | Haiyan Z.,Jiangnan University | Zaijun L.,Jiangnan University | Zaijun L.,Key Laboratory of Food Colloids and Biotechnology
Materials Research Bulletin | Year: 2016

CeO2/graphene was synthesized by a simple microwave method along with subsequent calcination. CeO2 nanoparticles with an average size of 68.8 nm are uniformly decorated on graphene nanosheets (CeO2/GNs). The CeO2/GNs displays a like-coral morphology. The architecture including overall connected framework, abundant intercrossed and interconnected nanochannels and perfect conducting network of the graphene, endows the CeO2/GNs material with a superior electron and mass transport. As a result, the CeO2/GNs gives a high specific capacitance of 503.4 F/g at 2 A/g and good cycle performance with 91.8% capacitance retention after 3000 cycles. Further, an asymmetric supercapacitors was assembled by using CeO2/GNs as the positive electrode and activated carbon as the negative electrode, the asymmetric device demonstrate a favorable energy density of 30.2 Wh/kg at the power density of 750.0 W/kg and superior cycle life with 86.4% the capacitance retenion at 5 A/g after 3000 cycles. © 2016 Elsevier Ltd Source

Yan T.,Jiangnan University | Li R.,Jiangnan University | Yang T.,Jiangnan University | Li Z.,Jiangnan University | Li Z.,Key Laboratory of Food Colloids and Biotechnology
Electrochimica Acta | Year: 2015

Electroactive materials with hollow nanostructures received great attractiveness due to large surface area, low density and superior structure permeablity. The paper reported a new template synthesis of nickel/cobalt layered double hydroxides (Ni/Co-LDH) without any adscititious alkali source, oxidant and step for removal of the template. Nickel nitrate, cobalt nitrate and SiO2 nanosphere were dispersed in an ethanol solution. Then, the mixed soution was heated at 160°C for 6 h to obtain Ni/Co-LDH product. During the process, ethanol and nitrate underwent a redox reaction releasing hydroxide ions, which will react with nickel and cobalt ions to form ultrathin Ni/Co-LDH nanoflakes. Meanwhile, SiO2 template was gently dissolved by hydroxide ions. Interestingly, perfect match between generation rate of Ni/Co-LDH nanoflakes and removal rate of the template creates an elaborate three-dimensional structure with well-defined hollow interior and hydrangea-like exterior. The unique structure will greatly improve electron and mass transfer during the faradic redox reaction. The Ni/Co-LDH electrode exhibits excellent electrochemical performance for supercapacitors. Its specific capacitance is up to 2158.7 F g-1 at the current density of 1 A g-1 and 1965.6 F g-1 at the current density of 5 A g-1. The capacitance can keep at least 97.5% of initial value after 1500 cycles. The study also provides prominent approach for the fabrication of hollow nanomaterials with three-dimensional structure for supercapacitors, Li-ion batteries, catalyst and sensors. © 2014 Elsevier Ltd. All rights reserved. Source

Juanjuan Z.,Jiangnan University | Ruiyi L.,University of Birmingham | Zaijun L.,Jiangnan University | Zaijun L.,Key Laboratory of Food Colloids and Biotechnology | And 3 more authors.
Nanoscale | Year: 2014

Graphene aerogel materials have attracted increasing attention owing to their large specific surface area, high conductivity and electronic interactions. Here, we report for the first time a novel strategy for the synthesis of nitrogen-doped activated graphene aerogel/gold nanoparticles (N-doped AGA/GNs). First, the mixture of graphite oxide, 2,4,6- trihydroxybenzaldehyde, urea and potassium hydroxide was dispersed in water and subsequently heated to form a graphene oxide hydrogel. Then, the hydrogel was dried by freeze-drying and reduced by thermal annealing in an Ar/H2 environment in sequence. Finally, GNs were adsorbed on the surface of the N-doped AGA. The resulting N-doped AGA/GNs offers excellent electronic conductivity (2.8 × 103 S m-1), specific surface area (1258 m2 g-1), well-defined 3D hierarchical porous structure and apparent heterogeneous electron transfer rate constant (40.78 ± 0.15 cm s-1), which are notably better than that of previous graphene aerogel materials. Moreover, the N-doped AGA/GNs was used as a new sensing material for the electrochemical detection of hydroquinone (HQ) and o-dihydroxybenzene (DHB). Owing to the greatly enhanced electron transfer and mass transport, the sensor displays ultrasensitive electrochemical response to HQ and DHB. Its differential pulse voltammetric peak current linearly increases with the increase of HQ and DHB in the range of 5.0 × 10-8 to 1.8 × 10-4 M for HQ and 1 × 10-8 to 2.0 × 10-4 M for DHB. The detection limit is 1.5 × 10 -8 M for HQ and 3.3 × 10-9 M for DHB (S/N = 3). This method provides the advantage of sensitivity, repeatability and stability compared with other HQ and DHB sensors. The sensor has been successfully applied to detection of HQ and DHB in real water samples with the spiked recovery in the range of 96.8-103.2%. The study also provides a promising approach for the fabrication of various graphene aerogel materials with improved electrochemical performances, which can be potentially applied in biosensors, electrocatalysis, and energy storage/conversion devices. This journal is © the Partner Organisations 2014. Source

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