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Nanoscience and Nanotechnology Commons

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2016

University of Massachusetts Amherst

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Articles 1 - 8 of 8

Full-Text Articles in Nanoscience and Nanotechnology

Label-Free And Aptamer-Based Surface Enhanced Raman Spectroscopy For Detection Of Food Contaminants, Shintaro Pang Nov 2016

Label-Free And Aptamer-Based Surface Enhanced Raman Spectroscopy For Detection Of Food Contaminants, Shintaro Pang

Doctoral Dissertations

The development of analytical methods to detect food contaminants is a critical step for improving food safety. Surface enhanced Raman spectroscopy (SERS) is an emerging detection technology that has the potential to rapidly, accurately and sensitively detect a wide variety of food contaminants. However, SERS detection becomes a challenge in real complex matrix, such as food, since non-specific matrix signals have the potential to drown out target associated Raman peaks. In this dissertation, we focused on the development and application of label-free, aptamer-based SERS in order to improve the accuracy and specificity of target contaminant detection in food. To accomplish …


Kinetics And Dynamics Of Electrophoretic Translocation Of Polyelectrolytes Through Nanopores, Harshwardhan Katkar Nov 2016

Kinetics And Dynamics Of Electrophoretic Translocation Of Polyelectrolytes Through Nanopores, Harshwardhan Katkar

Doctoral Dissertations

The idea of sequencing a DNA based on single-file translocation of the DNA through nanopores under the action of an electric field has received much attention over the past two decades due to the societal need for low cost and high-throughput sequencing. However, due to the high speed of translocation, interrogating individual bases with an acceptable signal to noise ratio as they traverse the pore has been a major problem. Experimental facts on this phenomenon are rich and the associated phenomenology is yet to be fully understood. This thesis focuses on understanding the underlying principles of polymer translocation, with an …


Investigate The Interactions Between Silver Nanoparticles And Spinach Leaf By Surface Enhanced Raman Spectroscopic Mapping, Zhiyun Zhang Nov 2016

Investigate The Interactions Between Silver Nanoparticles And Spinach Leaf By Surface Enhanced Raman Spectroscopic Mapping, Zhiyun Zhang

Masters Theses

Owing to their increasing application and potential toxicity, engineered nanoparticles (ENPs) have been considered as a potential agricultural contaminant that may pose unknown risk to human beings. However, many techniques require invasive and complicated sample preparation procedures to detect and characterize engineered nanomaterials in complex matrices. In the first part of this thesis, we present a non-destructive and label-free approach based on surface enhanced Raman spectroscopic (SERS) mapping technique to qualitatively detect and characterize gold nanoparticles (AuNPs), on and in spinach leaves in situ. We were able to detect the clearly enhanced signals from AuNPs at 15 to 125 nm …


Morphological And Material Effects In Van Der Waals Interactions, Jaime C. Hopkins Jul 2016

Morphological And Material Effects In Van Der Waals Interactions, Jaime C. Hopkins

Doctoral Dissertations

Van der Waals (vdW) interactions influence a variety of mesoscale phenomena, such as surface adhesion, friction, and colloid stability, and play increasingly important roles as science seeks to design systems on increasingly smaller length scales. Using the full Lifshitz continuum formulation, this thesis investigates the effects of system materials, shapes, and configurations and presents open-source software to accurately calculate vdW interactions. In the Lifshitz formulation, the microscopic composition of a material is represented by its bulk dielectric response. Small changes in a dielectric response can result in substantial variations in the strength of vdW interactions. However, the relationship between these …


Enzyme Stabilization In Hierarchical Biocatalytic Food Packaging And Processing Materials, Dana Erin Wong Jul 2016

Enzyme Stabilization In Hierarchical Biocatalytic Food Packaging And Processing Materials, Dana Erin Wong

Doctoral Dissertations

The partnership of biocatalysts and solid support materials provides many opportunities for bioactive packaging and bioprocessing aids beneficial to the agricultural and food industries. Biocatalysis, or reactions modulated by enzymes, allows bioactive materials to assist in bringing a substrate to product. Enzymes are proteins which catalyze reactions by lowering the activation energy required to drive the production of a desired product. Enzymes are commonly utilized in food processing as catalysts with specificity in order to enhance product quality through the production of beneficial food components, and to break down undesirable components that may be harmful or may decrease product quality. …


Refractive Index Engineering And Optical Properties Enhancement By Polymer Nanocomposites, Cheng Li Mar 2016

Refractive Index Engineering And Optical Properties Enhancement By Polymer Nanocomposites, Cheng Li

Doctoral Dissertations

The major part of this dissertation discusses the engineering of the refractive index of materials using solution-processable polymer nanocomposites and their applications in building optical components and devices. Three particular polymer nanocomposites have been introduced to achieve materials with tunable refractive indices and enhanced optical properties, which can be used to manipulate the behavior of light or electromagnetic radiations. In the first system, polyhedral oligomeric silsesquioxane (POSS)/polymer nanocomposites are developed. Thin films with tunable, low refractive indicies were fabricated from the composites. The mechanical strength of these films was characterized, and their application in antireflective coatings is discussed. In the …


(I) Polymer Nanocomposites: Rheology And Processing For Mesoporous Materials And (Ii) Nanopatterning Of Metal Oxides Using Soft Lithography, Rohit Kothari Mar 2016

(I) Polymer Nanocomposites: Rheology And Processing For Mesoporous Materials And (Ii) Nanopatterning Of Metal Oxides Using Soft Lithography, Rohit Kothari

Doctoral Dissertations

The research in this dissertation is categorized into two parts. The first part is focused on investigation of order-to-disorder transitions (ODT) in nanocomposites of an amphiphilic block copolymer containing various hydrogen-bonded additives, and fabrication of novel mesoporous silica based materials by utilizing such nanocomposites as templates. Disordered Pluronic®, poly(ethylene oxide) (PEO)−poly(propylene oxide) (PPO)−PEO triblock copolymer upon blending with small molecule additives containing hydrogen-bond-donating functional groups (carboxyl or hydroxyl) result into ordered nanoscale morphologies by preferentially interacting with the hydrophilic PEO chains in the Pluronic®. The dependence of ODT-temperature in these novel Pluronic®/small-molecule-additive complexes on composition, number and type of functional …


Complex Coacervate-Based Materials For Biomedicine, Sarah L. Perry, Whitney C. Blocher Jan 2016

Complex Coacervate-Based Materials For Biomedicine, Sarah L. Perry, Whitney C. Blocher

Chemical Engineering Faculty Publication Series

There has been increasing interest in complex coacervates for deriving and trans- porting biomaterials. Complex coacervates are a dense, polyelectrolyte-rich liq- uid that results from the electrostatic complexation of oppositely charged macroions. Coacervates have long been used as a strategy for encapsulation, par- ticularly in food and personal care products. More recent efforts have focused on the utility of this class of materials for the encapsulation of small molecules, pro- teins, RNA, DNA, and other biomaterials for applications ranging from sensing to biomedicine. Furthermore, coacervate-related materials have found utility in other areas of biomedicine, including cartilage mimics, tissue culture scaffolds, …