R&D Projects
In addition to our current sieving matrix products, which we continue to develop, we have the long-term goal of developing additional products:
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Polymer coatings for capillaries and microfluidic devices;
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A novel electrophoresis method that offers faster analysis than capillary gel electrophorsis and is ideally suited for the shorter separation lengths of microfluidic chips;
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"Lab-on-a-chip" technology for automated analysis of DNA, proteins, metabolites, and pathogens using sub-microliter sample volumes.
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Aptamers are an emerging class of molecules designed to rival antibodies in binding strength and specificity, which we are developing for diagnostic applications.
Expertise
We have extensive experience with laser-induced fluorescence detection, capillary electrophoresis, microfabricated electrophoresis chips using silica substrate, polymer coatings for silica substrate, entangled linear polymers for capillary sieving matrices, and latex beads attached to DNA oligos.
I. Polymers and Coatings
We are in the final development stage of a novel polymer for use as a capillary gel electrophoresis sieving matrix (gel) to separate DNA fragments by size. Sieving matrixes made from this polymer have properties unlike anything currently used. It is a non-acrylamide and hydrolytically-stable polymer that has high separation efficiency, medium viscosity, and does not require a coated capillary.
We are also developing this unique polymer as a coating for capillaries and micro-fluidic chips to reduce electro-osmotic flow and analyte-wall interactions over a wide pH range.
II. End-Labeled Free-Solution Electrophoresis
End-Labeled Free-Solution Electrophoresis (ELFSE) separates DNA molecules by attaching them to a "drag-label" of uniform size so that larger fragments will electrophoresis faster than smaller fragments in buffer. In this method, the drag-label is larger than the drag coefficient of the largest fragment to be separated.
We are currently studying the suitability of two drag-label candidates and have one pending patent.
The initial product will be a end-labeled oligos to be used as PCR primers that can be used for frament size analysis in existing capillary electrophoresis and microfluidic (lab-on-a-chip) platforms.
This method is ideally suited for microfluidic chip systems with shorter separation lengths since higher electric field strengths can be used with no loss of separation efficiency--it does not depend on polymer sieving selectivity as with conventional separations.
III. Lab-on-a-Chip
In addition to capillary, electrophoretic separations can be performed in "lab-on-a-chip" devices about the size of a microscope slide that contain microfluidic channels similar in function to capillary tubing.
Lab-on-a-chip devices allow multiple separations and complex sample preparations to be performed on microscopic size samples.
Separation lengths are typically a few centimeters, compared to tens of centimeters for a typical capillary length, allowing separations to be performed faster.
The chips are fabricated using photo-lithography in a clean room that is part of the Penn State Materials Research Institute, as shown.
A microfluidic chip for 2D separation of proteins in a "holder" that connects the microscopic channels to "macroscopic" fluidic controls, including valves and syringes. An inverted microscope and scanning laser are below the holder to observe fluid movement in the microscopic channels.
IV. Aptamers
Aptamers are synthetically produced oligonucleotides with a specific nucleotide sequence that has strong binding to specific targets, including proteins, small molecules such as metabolics, cells, and viruses. They can be conjugated to surfaces for use as capture agents or used in novel ways with fluorophors that emit only when bound to their target, allowing more sensitive detection.
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