EMSL: Yuehe Lin's Publications

Barry RC, Y Lin, J Wang, G Liu, and C Timchalk. 2009. "Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures ." Journal of Exposure Science and Environmental Epidemiology 19:1-18. doi:10.1038/jes.2008.71 Abstract This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are discussed. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are covered.

Kang X, J Wang, Z Tang, H Wu, and Y Lin. 2009. "Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in hybrid organic-inorganic film of chitosan/sol-gel/carbon nanotubes." Talanta 78(1):120-125. Abstract A hybrid organic-inorganic nanocomposite film of chitosan/sol-gel/multi-walled carbon nanotubes was constructed for the immobilization of horseradish peroxidase (HRP). This film was characterized by scanning electron microscopy. Direct electron transfer (DET) and bioelectrocatalysis of HRP incorporated into the composite film were investigated. The results indicate that the film can provide a favorable microenvironment for HRP to perform DET on the surface of glassy carbon electrodes with a pair of quasi-reversible redox waves and to retain its bioelectrocatalytic activity toward hydrogen peroxide.

Kou R, Y Shao, D Wang, MH Engelhard, JH Kwak, J Wang, VV Viswanathan, CM Wang, Y Lin, Y Wang, IA Aksay, and J Liu. 2009. "Enhanced Activity and Stability of Pt catalysts on Functionalized Graphene Sheets for Electrocatalytic Oxygen Reduction ." Electrochemistry Communications 11(5):954-957. Abstract Electrocatalysis of oxygen reduction using Pt nanoparticles supported on functionalized graphene sheets (FGSs) was studied. FGSs were prepared by thermal expansion of graphite oxide. Pt nanoparticles with average diameter of 2 nm were uniformly loaded on FGSs by impregnation methods. Pt-FGS showed a higher electrochemical surface area and oxygen reduction activity with improved stability as compared with commercial catalyst. Transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical characterization suggest that the improved performance of Pt-FGS can be attributed to smaller particle size and less aggregation of Pt nanoparticles on the functionalized graphene sheets.

Li Z, X Cui, X Zhang, Q Wang, Y Shao, and Y Lin. 2009. " Pt/Carbon Nanofiber Nanocomposites as Electrocatalysts for Direct Methanol Fuel Cells: Prominent Effects of Carbon Nanofiber Nanostructures ." Journal of Nanoscience and Nanotechnology 9(4):2316-2323. Abstract Carbon nanofibers (CNFs) with different microstructures, including platelet-CNFs (PCNFs), fish-bone-CNFs, and tube-CNFs, were synthesized, characterized and evaluated toward methanol oxidation reaction (MOR). The CNFs studied here showed several structures in which various stacked morphologies as well as the ordering of their size and graphite layers can be well controlled. Platinum nanoparticles have been electrodeposited on CNFs surfaces, and their electrocatalytic activities toward MOR have been studied by using cyclic voltammetry, chronoamperometry, and linear sweep voltammograms. Morphologies, textural properties, and the crystalline structure of the CNFs supports and catalysts have been characterized with transmission electron microscopy and scanning electron microscopy. The comparative tests conclude that Pt/PCNFs have the best electrocatalytic performance and good stability at room temperature. The high electrocatalytic activity and stability can be attributed to the specific microstructure of PCNFs, which have large numbers of edge-active carbon atoms on the surface of the CNFs as well as synergistic effects between CNFs and the platinum nanoparticles. The results suggest that PCNFs are excellent potential candidates as catalyst supports in direct methanol fuel cells.

Li Z, X Cui, and Y Lin. 2009. "Electrochemically synthesized ordered TiO2 and platinum nanocomposite electrode: preparation, characterization, and application to photoelectrocatalytic methanol oxidation." Journal of Nanoscience and Nanotechnology 9(4):2297-2302. Abstract In this work, the nanocomposite electrodes consisting of Pt and TiO2 nanotubular arrays have been synthesized, and the morphologies, structural, and photo-electrochemical properties of the electrodes are characterized by SEM, XRD, and electrochemical methods. Highly ordered TiO2 nanotubular arrays can be obtained through anodization of titanium. The platinum nanoparticles are electrodeposited into TiO2 nanotubes by a chronopotentiometry method. Cyclic voltammetry and XRD measurements can confirm the presence of platinum in this nanocomposite electrode. The nanostructural electrode greatly improved performances for methanol oxidation under UV-Vis illumination compared to that without illumination. An enhancement of 58% in the current density has been observed upon illumination with UV-Vis light irradiance at an intensity of 50 mW/cm2. The improved performance of the TiO2/Pt nanocomposite electrode results from a enhanced methanol oxidation by photo-generated holes in the TiO2 nanoarrays under illumination and a synergistic effectiveness between TiO2 and Pt nanoparticles.

Li J, and Y Lin. 2009. "Nanomaterials for Sensing and Electrocatalysis." Journal of Nanoscience and Nanotechnology 9(4):2173-2174. Abstract This special issue provides an overview of recent advances in nanomaterials for sensing and electrocatalysis. The emergence of nanoscience and nanotechnology has led to great advances in electrochemical science and technology, and these advances may lead to a new branch of electrochemistry research-electrochemical nanotechnology-that combines electrochemical techniques with nanotechnologies to address important issues in energy, electronics, environment, and heath care.

Ma Ham A, Z Tang, H Wu, J Wang, and Y Lin. 2009. "Protein-Based Nanomedicine Platforms for Drug Delivery." Small 5(15):1706-1721. doi:10.1002/smll.200801602 Abstract Drug delivery systems have been developed for many years, however some limitations still hurdle the pace of going to clinical phase, for example, poor biodistribution, drug molecule cytotoxicity, tissue damage, quick clearance from the circulation system, solubility and stability of drug molecules. To overcome the limitations of drug delivery, biomaterials have to be developed and applied to drug delivery to protect the drug molecules and to enhance the drug’s efficacy. Protein-based nanomedicine platforms for drug delivery are platforms comprised of naturally self-assembled protein subunits of the same protein or a combination of proteins making up a complete system. They are ideal for drug delivery platforms due to their biocompatibility and biodegradability coupled with low toxicity. A variety of proteins have been used and characterized for drug delivery systems including the ferritin/apoferritin protein cage, plant derived viral capsids, the small Heat shock protein (sHsp) cage, albumin, soy and whey protein, collagen, and gelatin. There are many different types and shapes that have been prepared to deliver drug molecules using protein-based platforms including the various protein cages, microspheres, nanoparticles, hydrogels, films, minirods and minipellets. There are over 30 therapeutic compounds that have been investigated with protein-based drug delivery platforms for the potential treatment of various cancers, infectious diseases, chronic diseases, autoimmune diseases. In protein-based drug delivery platforms, protein cage is the most newly developed biomaterials for drug delivery and therapeutic applications. Their uniform sizes, multifunctions, and biodegradability push them to the frontier for drug delivery. In this review, the recent strategic development of drug delivery has been discussed with a special emphasis upon the polymer based, especially protein-based nanomedicine platforms for drug delivery. The advantages and disadvantages are also discussed for each type of protein based drug delivery system.

Miao Y, H Wang, Y Shao, Z Tang, J Wang, and Y Lin. 2009. "Layer-By-Layer Assembled Hybrid Film of Carbon Nanotubes/Iron Oxide Nanocrystals for Reagentless Electrochemical Detection of H2O2." Sensors and Actuators. B, Chemical 138(1):182-188. Abstract A new approach to construct a reagentless H2O2 electrochemical sensor is described. Iron oxide magnetic nanocystals (IOMNs), as peroxidase mimetics, were employed to assemble a multilayer structure layer by layer. Polythionin was electrodeposited onto the glassy carbon electrode surface to introduce amino groups. Carboxyl functionalized multi-walled carbon nanotubes, amino functionalized IOMNs, and thionin monomers were anchored onto a polythionin-functionalized GC surface in order by carbodiimide or glutaraldehyde chemistry. The resulting multilayer construction with three layers of IOMNs and thionin mediator exhibits excellent electrochemical response to the reduction of H2O2, whereas such a modified electrode with one layer construction only yields a slight response to H2O2 of the same concentration. The tethered MWCNs enlarge the amount of immobilized IOMNs and effectively shuttle electrons between the electrode and the thionin.

Shao Y, J Wang, R Kou, MH Engelhard, J Liu, Y Wang, and Y Lin. 2009. "The Corrosion of PEM Fuel Cell Catalyst Supports and Its Implications for Developing Durable Catalysts." Electrochimica Acta 54:3109-3114. Abstract Studying the corrosion behavior of catalyst support materials is of great significance for understanding the degradation of PEM fuel cell performance and developing durable catalysts. The oxidation of Vulcan carbon black (the most widely-used catalyst support for PEM fuel cells) was investigated using various electrochemical stressing methods (fixed-potential holding vs. potential step cycling), among which the potential step cycling was considered to mimic more closely the real drive cycle operation of vehicle PEM fuel cells. The oxidation of carbon was accelerated under potential step conditions as compared with the fixed-potential holding condition. Increasing potential step frequency or decreasing the lower potential limit in the potential step can further accelerate the corrosion of carbon. The accelerated corrosion of carbon black was attributed to the cycle of consumption/regeneration of some easily oxidized species. These findings are being employed to develop a test protocol for fast screening durable catalyst support.

Shao Y, R Kou, J Wang, CM Wang, VV Vishwanathan, J Liu, Y Wang, and Y Lin. 2009. "The durability dependence of Pt/CNT electrocatalysts on the nanostructures of carbon nanotubes: hollow- and bamboo-CNTs." Journal of Nanoscience and Nanotechnology 9(10):5811-5815. Abstract The electrochemical durability of Pt/CNT with hollow- and bamboo-structured carbon nanotubes as the support for PEM fuel cells was investigated using cyclic voltammetry (CV, 0.6-1.1V) accelerated degradation test method. Pt/CNT catalysts were characterized with cyclic voltammograms, rotating disk electrodes, and TEM images. The changes in the electrochemical surface area of Pt and the activity toward oxygen reduction reaction (ORR) before and after the degradation indicate that bamboo-structured carbon nanotubes supported Pt (Pt/B-CNT) catalyst exhibited much higher durability. TEM images indicate that the sintering of Pt nanoparticles was much less for Pt/B-CNT. These are attributed to the specific bamboo-like nanostructures which provide more “bamboo-knot” defects and edge plane-like defects. Pt-support interaction was therefore enhanced and the durability was improved.