SBIR-STTR Award

The instrument we refer to as "Big Bang" uses a moderately powered laser flash to initiate the release of photolabile "caged" groups such as protons, which then will induce conformational changes in a biological polymer such as a protein or DNA. The conformational changes of the Polymer will induce acoustic waves within the solution resulting from phenomena such as changes in partial specific volume, electrostriction or changes in solvation. A piezoelectric transducer will detect the acoustic pressure waves (i.e. "listen" to the ultrasound generated) and deconvolution techniques will be used to analyze the kinetics of the resulting conformational change. Optical methods, including Rayleigh light scattering, will also be used to monitor conformational changes. With access to the nanosecond and microsecond time scales, this instrument will be orders of magnitude faster than traditional stopped flow techniques which typically have mixing times on the order of a millisecond. It should also be less expensive to build. We expect this instrument to find large markets in biotechnology research and industry, particularly in studies involving protein folding. We will build a prototype of this instrument and test the feasibility of this approach for measuring helix-coil transitions in a model protein system, poly-L-glutamate.Awardee's statement of the potential commercial applications of the research:This instrument will measure conformational changes in biopolymers such as proteins or DNA on time scales in the range of 10 nanoseconds to hundreds of microseconds. This instrument will find wide use in government and private laboratories, especially those interested in the fast events of protein folding.National Institute of General Medical Sciences (NIGMS)

Our goal is to produce a commercial instrument which combines the laser- induced photolysis of photolabile caged compounds and acoustic detection to obtain very fast kinetic information on biological molecules. In Phase I we built a prototype pulsed-laser photoacoustic instrument and showed that it could be used to measure the rates associated with the binding of protons to polypeptides. We now propose instrumental and software improvements that will dramatically extend the time range over which we can make measurements, as well as the quality of information that we can obtain. Using the improved instrumentation, we will perform a survey of the kinetics of release for commercially available caged compounds, extending from the nitrophenylethyl(NPE-) caged proton we used in our Phase I studies, to the numerous faster releasing caged compounds currently available. We will also continue and extend our polypeptide studies, adding control experiments and obtaining corroborating evidence of molecular relaxations using other kinetic approaches. The product of our work will provide researchers with a new tool to measure molecular relaxations by their kinetics, enthalpic changes, and volumetric changes, in a very important submillisecond time range, without the requirements of an intrinsic molecular chromophore.Proposed commercial application:The proposed instrument will be used to measure very fast kinetics of biological molecules on submillisecond time scales. Thus, it can serve the research community as a very fast alternative to stopped flow. As a general purpose photoacoustic device, it has many additional applications in a wide range of fields including pharmaceutical, photochemical, photophysical and environmental research.Thesaurus termsbiomedical equipment development, bridged cyclic compound, chemical kinetics, photolysis, protein folding, thermodynamics adenosine triphosphate, clathrate, computer program /software, computer system design /evaluation, hydrogen ion, nonclinical biomedical equipment, stop flow techniqueNational Institute of General Medical Sciences (NIGMS)