Sensors, Arrays, and Detectors

Many researchers are seeking to develop new tools that can detect and quantify the concentration of a wide variety of target analytes within a sample.

We have set about to develop new integrated chemical sensor array systems for simultaneous multi-analyte detection. In collaborative efforts with colleagues across UB we are focusing on the following research topics:

• The chemistry within sol-gel-derived xerogels
• Tailored xerogel-based sensors and biosensors
• New types of molecularly imprinted xerogels
• Small, low power light sources, sensors, and detectors
• Integrated systems

Students who carry out research in this area become exposed to modern instrumentation, pin-printing strategies, templating/imprinting schemes, biomolecule handling, electronics, codesign, assay development, and materials chemistry.

Tailored Materials

New materials are at the heart of numerous technologies. In our laboratories new materials are under development for chemical sensor platforms, to decrease bio-adhesion on ocean going vessels, and to improve wound restitution.

In collaborative efforts with Professor Detty in this Department we have been developing advanced types of anti-fouling materials for use in fresh water and marine applications.

In a multidisciplinary team effort with researchers across campus and colleagues at the Roswell Park Cancer Institute, we are developing novel resorbable laminated repair membranes for accelerated and sustained wound repair.

Students who conduct research in this area become exposed to modern instrumentation, biomolecule handling, biochemistry, bioengineering, bioassay development, materials chemistry, and interfacial chemistry.

Environmentally Friendly Chemistries

There is clear economic, environmental, energy-related, and political motivation to replace or at the very least minimize the use of certain liquids solvents.

Supercritical fluids (SFs) and room temperature ionic liquids (ILs) represent two alternative solvent systems that have attracted significant attention.

Our research group is focusing on the following topics:

• Oligomer/polymer tail and junction point accessibility, dynamics, and mobility in SFs and ILs
• Solvation at interfaces in contact with SFs and ILs
• Protein behavior in ILs

Students that conduct research in this area become exposed to modern instrumentation, polymers, surface chemistry, high-pressure chemistry, ionic liquids, and supercritical fluid science and technology.

Chemical Analysis of Things As They Are

Spectroscopic measurements are at the heart of many assays. Unfortunately, it is impossible to obtain accurate analytical information by using traditional spectroscopic techniques without performing a significant amount of sample pre-treatment before the measurement step.

We are developing multi-photon excited fluorescence techniques (MPEF) to allow “chemical analysis of things as they are”.

Students that conduct research in this area become exposed to modern ultrafast laser instrumentation, assay development, and novel sample handling strategies.

Instrumentation

Much of our research relies on state-of-the-art instruments. In cases where the requisite instrument is available commercially or available in other laboratories, we will either purchase the instrumentation or we will travel to those laboratories and collaborate. However, when the instrumentation for our needs is not available elsewhere or usage is impractical, we will design and construct our own instrumentation.

A partial listing of the major instrumentation that is available in our research laboratories includes the following:

• SLM model 48000 multi-harmonic Fourier instrument (frequency domain). This system is capable of routine steady-state fluorescence anisotropy and intensity, picosecond time-resolved fluorescence anisotropy and intensity decay, and phase-resolved fluorescence measurements.
• Hybrid SLM model 4850 fluorimeter. This system uses frequency-domain cross correlation detection with photomultiplier tubes or time-domain detection with a microchannel plate photomultiplier tube and time correlated single photon counting. The system is capable of steady-state and picosecond (frequency- and time-domain) fluorescence measurements under one-, two-, and three-photon excitation conditions.
• Femtosecond Ti:sapphire laser system. This system consists of a Coherent model Mira 900F Ti:sapphire laser, a cw argon-ion pump laser (Coherent, Model Innova 400), a pulse-picker (Coherent, Model 9200), and a second and/or third harmonic generation system (CSK, Model Super Doubler/Tripler). The system produces 100-200 fs long pulses at 725-950 nm (fundamental), 363-475 nm (second harmonic), and 242-317 nm (third harmonic). Average powers in excess of 1.5 W are possible.
• An IBH model 5000-W-SAFE with flashlamp (40 kHz), LED (1 MHz), and diode laser (1 MHz) excitation. This system is capable of performing picosecond and nanosecond time correlated single photon counting fluorescence measurements.
• A home built time-resolved fluorimeter. This system consists of N2 pump laser (PTI, Model GL-3300) and a dye laser (PTI, Model GL-301l). Detection is performed with a fast-wired photomultiplier tube and a 200 MHz digital oscilloscope (Tektronix, Model TDS 350). The dye laser output is tunable between 350 and 800 nm and produces 500 ps long pulses at 5-10 Hz. The system is ideal for recording time-resolved intensity decays when the excited-state lifetime exceed 50 ns.
• Two SLM model 8100 steady-state fluorimeters. These systems are capable of routine steady-state fluorescence anisotropy and intensity measurements.
• HP 8452A diode array spectrophotometer. This system is used for recording routine UV-Vis electronic absorbance spectra.
• Chromex model 250 cmi Raman system with CCD detection and custom high-pressure interface. This system is used for recording routine Raman spectra. Excitation is at 514.5 nm (argon-ion laser).
• Two (2) CCD-based Olympus BX-FLA fluorescence microscope. These systems are used for diagnostics and for reading our pin-printed chemical sensor arrays.
• A Cartesian Technologies model ProSys 5510 pin printer system. This system is used for forming chemical sensor arrays and for performing high throughput materials screening campaigns.
• CW argon-ion laser (Spectra-Physics model 164).
• CW intracavity-doubled argon-ion laser (Lexel Lasers model 95 SHG).
• Omnichrome He-Cd laser (325 nm).
• Liconix He-Cd laser (442 nm).
• Brookfield Engineering cone-plate viscometer.
• Over one dozen high- and mid-pressure pumps.
• A cache of high-pressure custom optical cells for supercritical fluid work. Most cells operate up to 300 bar and 350K. One cell is available to operate up to 2,500 bar.
• Six (6) dedicated IBM compatible PCs for off-line data analysis, simulations/modeling, graphics, code development and word processing.
• An extensive collection of optics, diagnostic tools, and shop tools.

All students that study in our research group become exposed to modern instrumentation, instrument design, and instrument construction.