In this lecture, we discussed the concept of nanoparticles and quantum dots. A nanoparticle has a solid object size and can be suspended in a solution. It is visualized with light by observation of fluorescence or absorption. Its advantages is that it can overcome photobleaching, shines brighter than other fluorescent sensors, and has a bigger stokes shift magnitude. Some of the disadvantages discussed include the permeation of cell membranes and the toxicity in the body. There are different types of nanoparticles, but the one focused in this lecture is the quantum dots. It was observed how quantum dots (exhibit semiconductor properties)(wasn't sure how to put this part) and a variety of variety of II-VI and III-V semiconductors can for quantum dots. The fabrication method for these quantum dots is by solvent-based chemical synthesis at elevated temperatures. The effects of the size of nanoparticles and quantum dots are then discussed. The issues with quantum dots including blinking that is not clearly understood, fluctuation of the emission wavelength, and the toxicity. Quantum Dots are not soluble in water which can make it difficult for them to detect biological assays. Some methods have been worked on to solve this problem. The quantum dot applications are then observed in cell labeling. The quantum dots can be tracked within the cell over time. This means that cell movement can be tracked along with the tracking of the cell contents. However, researchers are reluctant to release this for clinical use because no real research for long term toxicology has been done on them and the atoms used in this method are known to be toxic.
My research group is focused on the application of sub-wavelength optical phenomena and fabrication methods to the development of novel devices and instrumentation for the life sciences. The group is highly interdisciplinary, with expertise in the areas of microfabrication, nanotechnology, computer simulation, instrumentation, molecular biology, and cell biology. In particular, we are working on biosensors based upon photonic crystal concepts that can either be built from low-cost flexible plastic materials, or integrated with semiconductor-based active devices, such as light sources and photodetectors, for high performance integrated detection systems.
Using a combination of micrometer-scale and nanometer-scale fabrication tools, we are devising novel methods and materials for producing electro-optic devices with nanometer-scale features that can be scaled for low-cost manufacturing. Many of our techniques are geared for compatibility with flexible plastic materials, leading to applications such as low cost disposable sensors, wearable sensors, flexible electronics, and flexible displays. Because our structures manipulate light at a scale that is smaller than an optical wavelength, we rely on computer simulation tools such as Rigorous Coupled Wave Analysis (RCWA) and Finite Difference Time Doman (FDTD) to model, design, and understand optical phenomena within photonic crystals and related devices.
In addition to fabricating devices, our group is also focused on the design, prototyping, and testing of biosensor instrumentation for high sensitivity, portability, and resolution. Advanced instruments enable high resolution imaging of biochemical and cellular interactions with the ability to monitor images of biochemical interactions as a function of time. Using the sensors and instrumentation, we are exploring new applications for optical biosensor technology including protein microarrays, biosensor/mass spectrometry systems, and microfluidics-based assays using nanoliter quantities of reagents. The methods and systems developed in the laboratory are applied in the fields of life science research, drug discovery, diagnostic testing, and environmental monitoring. -From Professor Cunningham's Faculty Profile