纳米氧化铜修饰的苯巴比妥分子印迹传感器的制备及其电化学性能

为了改善分子印迹传感器的灵敏度, 在四丁基高氯酸铵的支持电解质溶液中, 以甲基丙烯酸为功能单体, 马来松香丙烯酸乙二醇酯为交联剂在纳米氧化铜修饰过的玻碳电极上电聚合了一种苯巴比妥(PB)识别性能的分子印迹传感膜. 采用循环伏安(CV)法、差分脉冲伏安(DPV)法及交流阻抗(EIS)法对这种纳米氧化铜修饰过的印迹及非印迹电极的电化学性能进行了研究, 结果显示纳米氧化铜修饰过的印迹及非印迹电极的电化学性能完全不同. X射线衍射(XRD)证实纳米粒子为氧化铜. 采用扫描电镜(SEM)对纳米氧化铜修饰过的印迹传感器的形貌进行分析, 发现纳米氧化铜分散在电极表面, 改善了修饰印迹传感器的识别点. 差分脉冲伏安法(DPV)表明苯巴比妥的浓度在1.0×10^-8-1.8×10^-4 mol·L^-1 范围内呈现良好的线性关系(线性相关系数R=0.9994); 检出限2.3×10^-9 mol·L^-1 (信噪比(S/N)=3). 研究结果表明纳米氧化铜修饰过的印迹传感器具有较高灵敏度及选择性. 此印迹传感器能用于实际样品中苯巴比妥的检测, 加标回收率在95.0%-102.5%.     

纳米氧化铜修饰的苯巴比妥分子印迹传感器的制备及其电化学性能

为了改善分子印迹传感器的灵敏度,在四丁基高氯酸铵的支持电解质溶液中,以甲基丙烯酸为功能单体,马来松香丙烯酸乙二醇酯为交联剂在纳米氧化铜修饰过的玻碳电极上电聚合了一种苯巴比妥(PB)识别性能的分子印迹传感膜.采用循环伏安(CV)法、差分脉冲伏安(DPV)法及交流阻抗(EIS)法对这种纳米氧化铜修饰过的印迹及非印迹电极的电化学性能进行了研究,结果显示纳米氧化铜修饰过的印迹及非印迹电极的电化学性能完全不同.X射线衍射(XRD)证实纳米粒子为氧化铜.采用扫描电镜(SEM)对纳米氧化铜修饰过的印迹传感器的形貌进行分析,发现纳米氧化铜分散在电极表面,改善了修饰印迹传感器的识别点.差分脉冲伏安法(DPV)表明苯巴比妥的浓度在1.0×10-8-1.8×10-4mol·L-1范围内呈现良好的线性关系(线性相关系数R=0.9994);检出限2.3×10-9mol·L-1(信噪比(S/N)=3).研究结果表明纳米氧化铜修饰过的印迹传感器具有较高灵敏度及选择性.此印迹传感器能用于实际样品中苯巴比妥的检测,加标回收率在95.0%-102.5%.     

Recent advances in electrochemical sensing for hydrogen peroxide: a review

Due to the significance of hydrogen peroxide (H(2)O(2)) in biological systems and its practical applications, the development of efficient electrochemical H(2)O(2) sensors holds a special attraction for researchers. Various materials such as Prussian blue (PB), heme proteins, carbon nanotubes (CNTs) and transition metals have been applied to the construction of H(2)O(2) sensors. In this article, the electrocatalytic H(2)O(2) determinations are mainly focused on because they can provide a superior sensing performance over non-electrocatalytic ones. The synergetic effect between nanotechnology and electrochemical H(2)O(2) determination is also highlighted in various aspects. In addition, some recent progress for in vivo H(2)O(2) measurements is also presented. Finally, the future prospects for more efficient H(2)O(2) sensing are discussed.     

Surface adsorption effects in the inkjet printing of an aqueous polymer solution on a porous oxide ceramic substrate

The inkjet printing of a polymeric solution into a porous substrate was studied, with the focus on phenomena occurring within the pore space during infiltration. Lines of aqueous polyacrylic acid (PAA) solution were printed onto the surface of porous, high-green-density ceramic powder beds. The PAA is a binder for the ceramic particles, allowing removal of the printed line structure ("primitive") and characterization of the extent of polymer penetration. Large differences in cross section of the retrieved printed structure were observed between ceramic systems and for different specific surface area powders. A mechanism for "filtration" of the polymer by adsorption onto the ceramic particle surfaces during infiltration was proposed. The adsorption of PAA onto Al2O3, SiO2, and TiO2 was characterized via adsorption isotherms, and the trend of primitive cross section with PAA adsorption was consistent with the filtration hypothesis, as was the variation with powder-specific surface area. These results can be generalized to other systems where a solution is inkjet printed onto a porous substrate (e.g., inks on plain paper, porous coated papers, etc.) Utilization of the adsorption effects may allow confinement of the solute molecules (e.g., colorant) to a small region near the substrate surface.     

PB/Au/CILE的制备与应用

混合离子液体(N-丁基吡啶六氟磷酸盐,[BuPy][PF6])与石墨粉,制备了离子液体碳糊电极(CILE),再采用电沉积法制得PB/Au/CILE修饰电极,研究了该修饰电极的电化学行为及其对H2O2的电催化,建立了H2O2的计时安培测定新方法。结果表明:在该修饰电极上PB产生了一对准可逆的氧化还原峰,并对H2O2表现出良好电催化作用,安培法测定H2O2的线性范围为5.0×10-6～1.55×10-4mol/L,检出限为1.0×10-6mol/L(S/N=3)。连续10次测定5.0×10-6mol/L H2O2峰电流的RSD为2.1%。     

Inkjet-printed monolayers as platforms for tethered polymers

Combining inkjet printing and atom-transfer radical polymerization (ATRP) provides a straightforward and versatile method for producing patterned polymer surfaces that may serve as platforms for a variety of applications. We report the use of drop-on-demand technology to print binary chemical gradients and simple patterns onto solid substrates and, by using surface-confined ATRP, amplify these patterns and gradients. Chemically graded monolayers prepared by inkjet printing dodecanethiol and backfilling with 11-mercaptoundecanol showed continuous changes in the water contact angle along the gradient. These samples also exhibited a distinct change in the intensity of methyl group and C-O stretching modes along the gradient. Graded or patterned polymer layers were produced by growing, with ATRP, tethered poly(methyl methacrylate) (PMMA) layers from gradient or patterned printed monolayers that contained a bromo-capped initiator. Atomic force microscopy and optical microscopy confirmed that the PMMA layers amplified the underlying printed initiator layer with remarkable fidelity.     

Patterned Paper Sensors Printed with Long‐Chain DNA Aptamers

There is growing interest in developing printable paper sensors to enable rapid testing of analytes for environmental, food safety, and clinical applications. A major challenge is to find suitable bioinks that are amenable to high‐speed printing and remain functional after printing. We report on a simple and effective approach wherein an aqueous ink composed of megadalton‐sized tandem repeating structure‐switching DNA aptamers (concatemeric aptamers) is used to rapidly create patterned paper sensors on filter paper by inkjet printing. These concatemeric aptamer reporters remain immobilized at the point of printing through strong adsorption but retain sufficient segmental mobility to undergo structure switching and fluorescence signaling to provide both qualitative and quantitative detection of small molecules and protein targets. The convenience of inkjet printing allows for the patterning of internally referenced sensors with multiplexed detection, and provides a generic platform for on‐demand printing of sensors even in remote locations.     

纳米粒子的制备及其在打印印刷领域的应用

本文简要介绍了几类纳米粒子的制备及其在打印印刷领域的应用.包括无机纳米粒子复合材料用于绿色打印制版、聚合物乳胶纳米粒子用于喷墨打印制备光子晶体、金属纳米粒子用于印刷电路以及纳米材料用于3D打印,并展望了其发展前景.     

Prussian Blue bulk modified screen-printed electrodes for H(2)O(2) detection and for biosensors

A sensor for H(2)O(2) amperometric detection based on a Prussian Blue (PB) bulk modified carbon screen-printed electrode was developed. It has been optimised with respect to the lowest limit of detection achieved. PB was made chemically by the reaction of FeCl(3) with K(4)[Fe(CN)(6)]. The resulting powder, obtained by forced crystallisation induced by acetone, was dried and activated at 150 degrees C for 10 h. PB microparticles (<38 mum) were prepared and mixed with carbon ink. The limit of detection achieved was 0.4 muM with the linear range up to 100 muM of H(2)O(2) with the sensitivity of 137 muA mM(-1) cm(-2), that was comparable with sensors based on electrodeposited PB film. The transducer was applied for a glucose biosensor, that exhibited LOD of 0.22 mM, linear range up to 3 mM, K(M)(app) of 4.6 mM, and the sensitivity of 3.21+/-0.16 muA mM(-1) cm(-2). The peroxide sensor, as well as the glucose biosensor, were totally insensitive to oxygen, ascorbate, urate, and paracetamol.     

An attempt of improving polyester inkjet printing performance by surface modification using β‐cyclodextrin

To improve the sharpness and the color yield of polyester fabrics with water‐based pigment inkjet printing, surface modification was proceeded using β‐cyclodextrin and citric acid. Fabrics were modified in the solution of β‐cyclodextrin with the concentration 100g/L and citric acid 100g/L. The line width and image area of printed patterns, which could evaluate the printing performances, on the modified polyester fabric were decreased by 77% and 62% in comparison with that of the control, respectively. The color yield characterized by the K/S value was enhanced by 47%. Scanning electron microscope and atomic force microscope images confirmed that the capillary effect was decreased and the surface roughness was increased after the surface modification. The microscope images of the printed patterns clearly showed that the sharpness and the color yield were improved. Thereby, β‐cyclodextrin modification offered a potential way to polyester pretreatment for pigment inkjet printing. Copyright © 2012 John Wiley & Sons, Ltd.     

Inkjet-printed thiol self-assembled monolayer structures on gold: quality control and microarray electrode fabrication

Laterally structured, self-assembled monolayers (SAMs) of different thiols (HS-R-X, R = (CH 2) 3-16, X = -CH 3, -COOH, -NH 2) on gold have been prepared by inkjet printing. The printer is a modified, low-cost desktop printer (Epson Stylus Photo R200), the ink is a 1 mM solution of the thiol in ethanol/glycerol (6:1). The quality of inkjet-printed large area SAMs obtained in this study is between that of a layer self-assembled from a thiol solution and that obtained by soft lithography, according to cyclic voltammetry, electrochemical impedance spectroscopy, scanning electrochemical microscopy (SECM), and polarization-modulated Fourier transform infrared reflection-absorption spectroscopy (PM IRRAS). For the first time, simultaneous printing of two different thiols in a single print job as an alternative to sequential printing and backfilling is demonstrated. The smallest structures consisting of conductive disks of 40 microm diameter were analyzed as single spots by SECM and as random array electrodes with different average disk-disk distance. Conductive band electrodes with variable bandwidth (300 microm to 1 cm) are presented, as well as a pH switchable band structure. As compared to stamping, inkjet printing allows for simultaneous multiple thiol printing in a single print job with the resolution limited only by the droplet size and the precision of the translation stage.     

Fabrication and electrochemical investigation of layer-by-layer deposited titanium phosphate/Prussian blue composite films

Composite films of titanium phosphate (TiPS)/Prussian blue (PB) were fabricated by the alternative deposition of TiPS layer and PB nanocrystals. The layer of TiPS was fabricated by adsorption of hydrated titanium from aqueous Ti(SO4)2 solution and subsequent reaction with phosphate groups. The layer of PB nanocrystals was fabricated by sequential adsorption of FeCl3 solution and K4[Fe(CN)6] solution. Regular deposition of TiPS/PB composite films were verified by UV-vis absorption spectroscopy and quartz crystal microbalance measurements. The successful fabrication of the TiPS/PB composite films was further confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Instead of producing films of TiPS layers alternating with PB nanocrystal layers, the TiPS/PB composite films have a structure in which the interstices of the PB nanocrystal films are filled with TiPS component. TiPS/PB composite films show enhanced electrochemical properties and improved stability in comparison with pure PB films prepared by the multiple sequential adsorption process. TiPS/PB composite films have the capability to catalyze the electrochemical reduction of H2O2 and can be used as a biosensor for detecting H2O2.     

Stamp transfer electrodes for electrochemical sensing on non-planar and oversized surfaces

This article describes a new alternative approach to the fabrication of printed electrochemical sensors and biosensors based on the transfer of electrode patterns comprising common conductive and insulating inks from elastomeric stamps to a wide variety of rigid and flexible substrates. This simple, low cost, yet robust methodology is demonstrated to be well-suited for the formation of electrochemical sensors on non-planar substrates and large objects/structures, which have traditionally been off-limits to conventional screen printing techniques. Furthermore, the stamped electrode devices are shown to exhibit electrochemical performance that rivals that of their screen printed counterparts and display resilience against severe mechanical deformation. The stamp transfer approach is further extended to the demonstration of epidermal electrochemical sensors through the transfer of the electrode patterns directly onto the skin. The resulting sensors demonstrate a wide range of usability, from the detection of various physiological analytes, including uric acid on the skin, to the identification of residues originating from the handling of munitions and explosives. The migration of printable electrochemical sensors to non-conventional (non-planar and/or oversized) surfaces provides new opportunities within the personal healthcare, fitness, forensics, homeland security, and environmental monitoring domains.     

Controlled orientation and alignment in films of single-walled carbon nanotubes using inkjet printing

An inkjet printing procedure for depositing films of carbon nanotubes (CNTs) that exhibit a very high degree of long-range mutual alignment as well as a controlled orientation with respect to the printed geometry is presented. CNT self-assembly was induced by the intrinsic lyotropic liquid crystallinity of CNT suspensions. Sufficient concentrations are reached by matching the inkjet deposition rate to the numerically modeled local evaporation rate of the printed feature and enable the CNT suspension to be printed using standard inkjet printing. Surface alignment was verified using scanning electron microscopy (SEM) and polarized light microscopy. In addition, the bulk morphology was investigated and found to be composed of stacked planar layers that did not necessarily have the same long-range orientation found on the surface. The bulk morphology was characterized by removing layers through an elastomeric peeling process and by observing cross sections of the films using SEM. CNT concentration and length were spanned experimentally, and it was found that very short and very long CNTs as well as low concentration suspensions did not yield long-range alignment.     

New directions in screen printed electroanalytical sensors: an overview of recent developments

Screen printing is widely used to fabricate disposable and economical electrochemical sensors and has helped us to establish the route from 'lab-to-market' for a plethora of sensors. We overview recent developments in the field where screen printed electrochemical sensors are utilised. Starting with their fundamental understanding, through to highlighting new developments in bulk metal and mediator modified electrodes, as well as novel advantageous electrode designs, we demonstrate the wide and diverse range of applications that sensors based on this fabrication approach have achieved.     

Nanoinks in inkjet metallization — Evolution of simple additive-type metal patterning

Recent advances in the development of stable dispersions of nanophase metal particles have allowed the direct fabrication of metal patterns (e.g., printed circuits, RFID tags, touch screens, etc.) by simple additive type inkjet processes. Such processes replace the more costly and less environmentally friendly subtractive lithographic type photoprocesses involving selective etching of photoresists and metal layers and more complex additive type process using photocatalysts for patterned metal deposition by electroless plating processes and inkjet patterning of metal catalyst or catalyst precursor for subsequent metallization by electroless plating. The recent development of electrohydrodynamic jet printing (e-jet printing), in which the ink drop is ejected under the influence of an electric field, has allowed a significant resolution increase vs. conventional inkjet printing with a piezoelectric head (printing resolution of ca. 100 nm for e-jet printing vs. ca. 20 μm for inkjet printing).     

Layer-by-layer inkjet printing of fabricating reduced graphene-polyoxometalate composite film for chemical sensors

Graphene oxide (GO) nanosheets and polyoxometalate such as H(3)PW(12)O(40) (PTA) are prepared into a multilayer film via a layer-by-layer inkjet printing method. The GO/PTA composite thin film shows linear, uniform and regular layer-by-layer growth. Under UV-irradiation, a photoreduction reaction takes place in the film which converts GO to reduced GO (rGO) due to the photoreduction activity of polyoxometalate clusters. According to the cyclic voltammograms measurement, the rGO/PTA composite film displays good electrocatalytic activity for the oxidation of dopamine (DA). The oxidation peak current (I(pa)) increases gradually with increasing the dopamine concentration, which may be used in electrochemical biosensors.     

Electrochemical Conversion of Magnetic Nanoparticles Using Disposable Working Electrode in a 3D‐Printed Electrochemical Cell

Exploration of new property/function of nanomaterials is always a strong impetus in the nanoscience field. Here, a new method of electrochemical conversion (ECC) of magnetic nanoparticles (MNPs) is proposed to endow MNPs with signal generation ability for sensing. Briefly, high potential was applied to split H₂O to generate acid, while Fe₃O₄ MNPs reacted with H⁺ and produce ferric/ferrous ions, which further reacted with K₄Fe(CN)₆ to yield Prussian blue (PB) through potential cycling. The ECC method worked well on both home‐made and commercial MNPs with different sizes. The generated PB possessed strong electrochemical activity for further applications. Interestingly, an uneven deposition of PB on working electrode and undesired contamination of the reference and counter electrodes were found when using commercial integrated three‐electrode chip. A 3D‐printed electrochemical cell was designed to facilitate the ECC and avoid drawbacks of commercial integrated electrode. The 3D‐printed electrochemical cell was proven to solve the problem above through spatial separation of electrodes and thus facilitated the ECC process. An electrochemical sensor for H₂O₂ detection based on the catalysis ability of ECC‐based PB exhibited a linear response from 5 μM to 1 mM, a high sensitivity of 269 μA mM^?1 cm^?2 and a low detection limit of 0.16 μM (S/N=3), which suggests its promising application prospect in electrochemistry‐related analysis.     

A non-enzymatic sensor for hydrogen peroxide based on polyaniline, multiwalled carbon nanotubes and gold nanoparticles modified Au electrode

We describe the construction of a polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) modified Au electrode for determination of hydrogen peroxide without using peroxidase (HRP). The AuNPs/MWCNT/PANI composite film deposited on Au electrode was characterized by Scanning Electron Microscopy (SEM) and electrochemical methods. Cyclic voltammetric (CV) studies of the electrode at different stages of construction demonstrated that the modified electrode had enhanced electrochemical oxidation of H(2)O(2), which offers a number of attractive features to develop amperometric sensors based on split of H(2)O(2). The amperometric response to H(2)O(2) showed a linear relationship in the range from 3.0 μM to 600.0 μM with a detection limit of 0.3 μM (S/N = 3) and with high sensitivity of 3.3 mA μM(-1). The sensor gave accurate and satisfactory results, when employed for determination of H(2)O(2) in milk and urine.     

Inkjet fabrication of hydrogel microarrays using in situ nanolitre-scale polymerisation

Polymer hydrogel microarrays were fabricated by inkjet printing of monomers and initiator, allowing up to 1800 individual polymer features to be printed on a single glass slide.