Technology

A Novel Purification Technology - NanoChromatography*

Argylla Technologies perceived that there is a major technological need to process samples with low microgram, nanogram, or even picogram quantities of nucleic acid or protein. This is exactly the type of sample with the highest attributed value for research, forensics and clinical applications. The NanoChromatography that Argylla has developed is a unique form of batch chromatography that uses ceramic nanoparticles in colloidal suspension as the basis for purifying DNA, RNA, and proteins at this valuable, low-concentration range. Argylla NanoChromatography products and protocols are designed to be “simple-to-use” and easily scale between the nanogram and the microgram sample scale without major changes. For example, the Argylla DNA nanoPurify Kit, is designed to isolate, purify, and concentrate DNA from samples as large as 500 microliters: to produce a highly purified, concentrated DNA product in a final elution volume as small as 10 microliters. It captures and purifies DNA via a one-pot process from start to finish in a standard microfuge tube. Argylla's deep expertise in separation science, microarray development, nucleic acid and protein chemistry has been key to the development of NanoChromatography.

Nanoparticle Ceramics as Matrix for Very-Small-Scale Chromatography. Argylla has developed a unique set of chromatography matrices based on highly purified, nearly monodisperse, ceramic nanoparticles. These nanoparticles form stable colloidal suspensions in aqueous solution, but are dense enough that they readily sediment form a well defined pellet in response to standard low speed bench top centrifugation. Since the particles are sub-micron in diameter, they display a large surface area to volume ratio. For example, one milliliter of an Argylla nanoparticle suspension at 0.1% (1mg/ml) displays a total surface area in the range of 200 cm^2. Due to the small size of these particles, this same 0.1% suspension will occupy, once sedimented, a pellet volume of only about one microliter. The expansive surface area of these ceramic nanoparticles confer very useful characteristics for chromatography applications: a high mutually repulsive surface charge and the ability to be readily coated or modified via a number of well-known surface chemistries.

High Binding Capacity and Enhanced Kinetics. Because there are many Argylla particles per unit mass, the inter-particle distance in a standard Argylla nanoparticle suspension is very small and is nearly ideal for high speed molecular binding reactions. For example, in a milliliter of a 0.1% suspension, the number of dispersed Argylla particles would be in the 10¹² range, with a corresponding average inter-particle spacing of about a micron. In general, a micron spacing is nearly ideal since this distance is less than the distance a 10,000 base pair long DNA molecule or a 1,000,000 D protein would travel by passive diffusion in about one minute. In the absence of mixing or convective flow, within 0.1% suspension of these Argylla nanoparticles, the targeted biomolecule is never more than “a minute away” from binding to the surface of these nanoparticles. This means that binding to these particles is almost independent of biomolecule concentration, thus batch chromatography with Argylla nanoparticles will be complete within minutes.

Achieve Hundred-Fold Sample Volume Reduction Over a Thousand-Fold Concentration Range. For a smooth, non-porous particle, the surface area per unit mass increases as 1/diameter. For batch chromatography, this outer surface area is important because it defines the mass and the volume of sample that can be processed at one time. To match the surface area displayed by a milligram of Argylla nanoparticles (which present 200 cm²/mg of surface area) a standard chromatographic matrix made of 30 micron-size beads (about 2cm²/mg) would require 100 milligrams of particles, since they are about 100- times larger. Assuming that each kind of matrix occupies about the same volume of water when sedimented to form a pellet, the surface area presented by a 1 microliter Argylla nanoparticle pellet is equivalent to surface area displayed by a 100 microliter pellet composed of of 30 micron-size beads.

Chemical Coating of Ceramics. Key to the rapid development of new chromatography platform is the ability to chemically modify the surface of this new matrix with biomolecule-specific ligands. For ceramics of the kind used for Argylla nanoparticles, the chemistry for modifying the surface is well studied and has been optimized for related applications in the plastics and polymers industry. At Argylla, we have taken these ceramic surface chemistries and paired them with a deep understanding of biochemical chromatography, to develop a flexible repertoire of surface coatings for DNA, RNA and protein applications.

*Patent pending