Research Terms
Researchers at the University of Central Florida have developed an inexpensive, reliable sensor that can rapidly and simultaneously detect traces of multiple heavy metals in water. With its unique biopolymer-metal composite thin film, the device provides improved sensitivity for identifying toxins in situ, including mercury, cadmium, arsenic, chromium, thallium, lead and zinc.
As part of the technology development, the researchers also invented a novel fabrication process to produce the new composite film. Manufacturers can use the process to reduce costs significantly. With existing fabrication methods, an electrode (microsensor) can cost hundreds of dollars. In contrast, the UCF method provides an electrode with an estimated cost of less than $1. As an example, the technology offers the capability to develop an instrument that easily connects to a kitchen faucet to monitor heavy metal ions in drinking water.
Technical Details
The invention comprises a sensing device and a method for fabricating the device. A key aspect of the technology is a novel and simple electrodeposition method in which a metal ion and a polysaccharide form an integrated biopolymer-metal composite film. The process is more cost-effective than photolithography or physical deposition. It produces an electrode suitable for use aquatically to monitor the concentration of heavy metal ions or for in situ analysis of leachate heavy metal ions in water. Examples of metal ions used to make the composite film are iron (Fe), copper (Cu), or bismuth (Bi). Polysaccharide examples include chitosan or chitin.
In one example application, the researchers created two biopolymer-metal composite film-based sensors: one made of Bi-chitosan and another made of Fe-chitosan. Using the sensors with square-wave anodic stripping voltammetry (SWASV), the researchers simultaneously analyzed concentrations of heavy metals in real mining wastewater. They used the Bi-based composite film sensor to detect cadmium (Cd2+) and lead (Pb2+), and the Fe-based composite to detect arsenic (As3+). The detection limits observed in parts per billion (ppb) were 0.5 of Cd, 1 of Pb, and 3.75 of As.
Partnering Opportunity
The research team is looking for partners to develop the technology further for commercialization.
Stage of Development
Prototype available.
Microfluidics, or "lab-on-a-chip" technology, is experiencing explosive growth in the fields of chemistry, biology, electronics, and computers. These small devices work by allowing liquids and gases to flow through them, providing constant contact with the material of interest for continuous monitoring with a minimal sample volume. UCF researchers have taken this technology to the next level by developing a portable hand-held water monitor capable of determining microbe growth, chlorine content, purity, or temperature. This new device and cartridge system would provide simple water quality testing for environmental agencies, water treatment facilities, and any company selling water testing kits for home use.
Advantages
Using this technology, you can create an array of flexible devices for monitoring all the parameters of water quality, including chlorine content, temperature, or microbe levels via Biological Oxygen Demand (BOD). Previously, BOD measurements required five days to determine microbe levels by observing the depletion of dissolved oxygen. Now, due to its rapid feedback and portability, this device can be deployed on site for real-time water quality detection. Integrated with the device are an inexpensive, durable, chemically inert substrate and a temperature sensor, which takes into account all thermal effects on the chlorine concentration.
Technical Details
This technology uses inert polymers for the consistent packaging of an electrode layer, microbial layer, and microfluidic inlet and outlet ports. One embodiment is a disposable microsensor for continuous monitoring of free chlorine in water, while another is a disposable microbial sensor for rapid BOD measurement. For the chlorine sensor, gold, gold and silver/silver chloride comprise working, counter, and reference electrodes respectively. A transparent Cyclic Olefin Copolymer (COC) substrate is used for sensor fabrication by standard lithographic procedures. For the microbial sensor, a microbial strain is immobilized over one pair of sensor electrodes while the other is retained as a reference, where the BOD values of the sample can be measured in terms of the difference between the output signals. The sensor layer is attached to an injection molded passive microfluidic channel on top, used for a microfluidic package. This sensing circuitry is further connected to the display monitor showing the output data.
Researchers at the University of Central Florida have developed a method that overcomes issues associated with mass producing interconnecting microfluidic chips. The field of microfluidics aimes at developing miniaturized devices that can robustly sense specific properties of a sample using minimal sample volumes. Development of biological and chemical microfluidic sensors is challenging due to the lack of adequate packaging platforms and standardized tubing. Creating connections between various microfluidic devices is cumbersome, due to fragile connections that are difficult to make.
Technical Details
The UCF technology provides a method for mass producing interconnecting microfluidic chips. The microfluidic packagings have two or more integrated connectors with standardized sizing that permits the chips to interlock. The design incorporates standard size tubing that readily allows for leakproof interlocking between the chips. The manufacturing method uses an injection molding process to reliably and cost-effectively mass produce the chips.
