A former scientist from Texas-based R&D firm Lynntech who was developing a nucleic acid sample prep module intended for use with molecular diagnostic assays for resource-poor areas of the world has left the company and founded his own startup to commercialize an improved version of the technology.
The researcher, Season Wong, introduced his company, called AI Biosciences, and its magnetic particle-based sample prep cartridge for the first time last month at the Knowledge Foundation's Sample Prep conference in San Diego.
Typical magnetic particle-based nucleic acid extraction and purification involves lysing a sample using chaotropic agents, heat, or sonication; binding the nucleic acids to the particles; washing the particles to remove PCR inhibitors; washing again with different buffers; and eluting the nucleic acids from the particles for downstream amplification and detection. However, this protocol can be laborious and time-consuming; is typically performed in an open system, making it prone to cross-contamination; and may not be amenable for use in front of point-of-care diagnostics in resource-poor areas of the world.
AI Biosciences' sample prep technology attempts to consolidate all of these steps into a single, self-contained, easy-to-use, and inexpensive cartridge. Based on Wong's multi-chamber syringe design, the cartridge contains 100-µL to 2-mL individual chambers with pre-loaded reagents separated inside the barrel of the syringe by movable stoppers.
To operate the cartridge, a user simply places the needle of the syringe into the sample containing nucleic acids that need to be purified. Then, the syringe can be either manually operated by an individual or automatically operated with a syringe pump.
"If it's a liquid [sample] it's easier, because the container already has the lysis buffer and magnetic particles, and the lysis buffer will release the RNA and DNA and the material will be captured by the magnetic particles," Wong told PCR Insider.
Those magnetic particles are then captured or pooled into a recess or dimple on the wall inside the syringe, and plunging the syringe exposes the particles to whatever other reagents are necessary – typically a few wash reagents and elution buffer – to complete the extraction.
Wong said that the physical geometry of the cartridge is "much improved" over that of the cartridge he was developing at Lynntech (PCR Insider, 12/15/2011). "That cartridge was kind of pre-fixe … but in the new cartridge … the amount of the volume you put in there is very flexible. You could put in different sample and reagent volumes depending on your application. If your application is something that requires a larger volume, you may have to put a larger volume of lysis buffer in."
This is important because different applications – particularly molecular diagnostics – use different sample matrices and volumes. For example, Wong noted, a typical blood-based diagnostic test may use 1 mL of blood, but in the case of sepsis diagnostics some clinicians will want to process up to 5 mL of blood because the pathogen is exceedingly rare.
"You need to use a higher volume to catch the pathogen in the blood," Wong said. "Some of them are even in the range of one [colony-forming unit], or pathogen, per mL, so a 10- or 100-µL extraction will not help."
So far Wong has collaborated with other researchers to test the sample prep cartridge for a variety of sample matrices and applications, including buccal swabs for human DNA profiling, human whole blood spiked with gram-positive bacteria cells, and human serum spiked with dengue virus.
In all cases the syringe successfully purified and eluted DNA or RNA within minutes for successful downstream PCR amplification and profiling. In general, Wong said, extraction and purification can be completed in less than 15 minutes with a hands-on time of about three minutes.
Wong is hoping that the cartridge can be used as a "plug-and-play" device in front of a variety of downstream nucleic acid analysis methods. In order to achieve this goal, AI Biosciences needs to further develop a second version of the cartridge that contains a dispensing port along the side of the syringe so that the eluted nucleic acid can be easily deposited onto a lab-on-a-chip, Eppendorf tube, or some other appropriate receptacle for further processing.
Wong's primary goal with AI Biosciences, as it was at Lynntech, is to couple the cartridge with a point-of-care nucleic acid amplification device for diagnosing disease in the developing world.
The intellectual property surrounding his previous technology still resides with Lynntech, but Wong noted that his new technology is differentiated, and that he has applied for a provisional patent on it. "One of the reasons I left is I saw the company was not doing much with the technology," he said. "There is a lot going on at Lynntech, it's a big R&D company, and lots of us get lots of different grants. They are sometimes comfortable getting the grants and not wanting to commercialize the technology. That's why I'm putting my efforts into AI Biosciences."
Wong added that he has some ideas about a low-cost, ultra-fast thermal cycling technology for PCR amplification, and that he would eventually like to also develop that technology at AI Biosciences for use with the sample prep cartridge.
However, for the time being, AI Biosciences will focus on garnering interest from potential partners that want to use the sample prep cartridge in applied markets. Although it is early days at the company, Wong said the greatest interest he has seen so far is in the area of biodefense and food safety testing.
Furthermore, in order to potentially generate cash to fund the development of a rapid POC MDx device, AI Biosciences is trying to market the syringe for other applications besides nucleic acid purification, such as pharmaceutical drug delivery and mixing.
"There is only so much a small company can do, but I think this would be a good way to get some financial reward so I can work on molecular detection," Wong said. "The beauty of these technologies is that they are all derived from a basic syringe so the materials compatibility and user learning curve are non-issues."