Biomedical subjects

D D Dlott

Publications and source records attributed to D D Dlott.

5 recordsLinked to original sources

PubMed2005

Printing of protein microarrays via a capillary-free fluid jetting mechanism.

Current proteomics experiments rely upon printing techniques such as ink jet, pin, or quill arrayers that were developed for the creation of cDNA microarrays. These techniques often do not meet the requirements needed for successful spotting of proteins to perform high-throughput, array-based proteomic profiling. Biological laser printing (BioLP) is a spotting technology that does not rely on solid pins, quill pins, or capillary-based fluidics. The non-contact mechanism of BioLP utilizes a focused laser pulse to transfer protein solutions, thereby eliminating the potential for orifice clogging, air bubbles, and unnecessary volume loss potentially encountered in commercially available spotting technologies. The speed and spot-to-spot reproducibility of BioLP is comparable to other techniques, while the minimum spot diameter and volume per printed droplet is significantly less at 30 microm and approximately 500 fL, respectively. The transfer of fluid by BioLP occurs through a fluid jetting mechanism, as observed by high-speed images of the printing process. Arraying a solution of BSA with subsequent immunodetection demonstrates the reproducible spotting of protein in an array format with CVs of <3%. Printing of the enzyme alkaline phosphatase followed by a positive reaction with a colorimetric substrate demonstrates that functional protein can be spotted using this laser-based printer.

Alkaline Phosphatase↗

PubMed2000

Nanoshocks in molecular materials.

Nanoshocks are tiny but powerful laser-driven shock waves that can be used to produce large-amplitude compression in molecular materials on the picosecond time scale. When coupled with ultrafast molecular spectroscopy, the molecular response to nanoshocks can be probed in detail. Simple molecular systems (anthracene crystals) are used to characterize the nanoshock pulses. Well-characterized nanoshocks are used to study complex phenomena such as shock-induced chemical reactions, shock-induced orientation of energetic solids, and shock compression of organic polymers and proteins.

Lasers↗

PubMed1999

Ultrafast spectroscopy of shock waves in molecular materials.

Recent progress in combining the techniques of time-resolved molecular spectroscopy with shock compression science is reviewed. Shock wave spectroscopy probes the response of molecules to high-speed, large-amplitude mechanical transients and is an important way of studying physical chemical phenomena that involve large-amplitude displacements. A brief discussion of the continuum model for shock compression and a molecular model for the shock front is presented. Methods for generating and detecting shock effects are reviewed. Several applications of shock spectroscopy are reviewed, including high explosives, the nanoshock technique that uses ultrafast lasers, and shock compression of biological molecules.

Journal Article↗

PubMed1986

Ligand binding to heme proteins: relevance of low-temperature data.

Binding of carbon monoxide to the beta chain of adult human hemoglobin has been studied by flash photolysis over the time range from about 100 ps to seconds and the temperature range from 40 to 300 K. Below about 180 K, binding occurs directly from the pocket (process I) and is nonexponential in time. Above about 180 K, some carbon monoxide molecules escape from the pocket into the protein matrix. Above about 240 K, escape into the solvent becomes measurable. Process I can be observed up to 300 K. The low-temperature data extrapolate smoothly to 300 K, proving that the results obtained below 180 K provide functionally relevant information. The experiments show again that the binding process even at physiological temperatures is regulated by the final binding step at the heme iron and that measurements at high temperatures are not sufficient to fully understand the association process.

Carbon Monoxide↗

PubMed1983

Nanosecond flash photolysis study of carbon monoxide binding to the beta chain of hemoglobin Zürich [beta 63(E7)His leads to Arg].

Binding of carbon monoxide to beta chains of hemoglobin Zürich has been studied by flash photolysis over the time range of nanoseconds to seconds at temperatures from 20 to 300 K. From 20 to 200 K a single rebinding process (process I) is seen, characterized by a distribution of barrier heights with a peak enthalpy of 2.3 kJ/mol. Above 200 K some ligands escape from the pocket into the matrix, and above 260 K recombination from the solvent sets in. Process I is visible up to 300 K, but above 200 K its rate remains essentially constant at about 4 X 10(8)s -1. Above about 250 K, process I is exponential in time, indicating rapid conformational relaxation. The results are discussed within the framework of a sequential model for ligand binding.

Arginine↗