7 Tips for Purchasing Your Next Cell Sorter

Define your needs.

While defining your needs seems like an obvious first step, having a crystal clear idea about what those needs actually are will ensure you don’t pay for instrument features you don’t need, possibly saving you tens of thousands of dollars.

Shared Resource Labs (SRLs)

If you run an SRL, start by querying the end users. What are their intended downstream applications? What cell types will they want to sort? For microparticles and bacteria, for example, you may require a more sensitive detector. If a lot of work is being done with red fluorescent proteins, be sure to get a 532 or 561 nm laser. You may also need to be sure your users are comfortable sorting mammalian cells on an instrument that is also being used to sort microbes. Are any of the target cell populations rare? Gathering this information will allow you to triage needs versus wants and help you determine how many parameters (realistically) and what event rates (in the case of rare cell types) will be required for sorting.

If you run an SRL, you may be worried about trying to accommodate every type of sorting request. But a survey of your users may show that most need to sort only GFP-expressing cells (for example, to enrich for positively transfected cells). If this is the case, then you will likely be better off purchasing a workhorse system designed specifically for simple sorts. However, if you need to accommodate users with high-parameter sorts (more than 10 colors) as well as users requiring only a few colors, you might consider purchasing two different instruments, as this university stem cell core facility did. This way, you can maximize your resources and ensure that your lab is running as efficiently as possible.  

Individual Labs

You will need to keep a different set of considerations in mind if you are looking to purchase a dedicated cell sorter for your own lab. One of the most important is whether your lab consists of flow cytometry veterans or molecular biologists looking to take advantage of fluorescence-activated cell sorting (FACS) for the first time. Many cell sorting systems are incredibly sophisticated, have complex setup processes, and are controlled by equally complex software. The learning curve for these types of cell sorters is steep and will require a considerable time investment for training.

Who will be in charge of operating and maintaining the instrument? If your lab experiences a lot of turnover, who will train the trainer? You don’t want to find yourself in a situation where you no longer have a dedicated operator, ultimately halting experiments that rely on your cell sorter. If you think this might be the case, then you will likely be better off with an instrument that has been designed for ease of use, such as the S3e Cell Sorter. Note that these kinds of systems can also be beneficial to SRLs that have a heavy training burden or that are experiencing instrument backlog from many simple sort requests (1–2 parameters).

Pay attention to instrument footprint.

For many, bench space comes at a premium, so you will want to get a full understanding of each instrument’s total footprint. Marketing materials from the different instrument manufactures often do not showcase every component of the instrument that is required for operation. For example, most cell sorters utilize an external pressure regulator or fluidics cart, both of which can be bulky. Note that some manufacturers label even large, sophisticated instruments as benchtop sorters. Check the size specs. You may also need to look into whether the manufacturer offers a biosafety hood or cabinet and what the footprint is for this as well, as these can also vary greatly in size.

Survey the market.

You probably already have an idea of the major players in the market, but even if you don’t, simply typing the query “flow cytometers” or “cell sorters” in your browser yields several different instrument manufacturers within the first two pages of a Google search. Follow these links and collect information about the various instruments. Use an electronic note-taking application, such as Evernote, to keep everything together and make notes as you go through the process. For websites where information and marketing materials are not easily accessible, try sending an email to your local sales representative.

Learn how to read marketing materials.

Instrument brochures usually list instrument specifications, such as the number of lasers and detectors, but don’t forget to check other relevant information. For example, can the instrument be upgraded in the field? Is remote support available for troubleshooting so you can avoid the delay of an onsite service call? This is also a good time to get a better understanding of the instrument manufacturer’s commitment to the field. Explore their website to see if they have invested in the development of resources such as online tools, how-to videos, protocols, and other tips or guides. This kind of content can go a long way in ensuring your success and can be especially helpful if your lab is new to FACS. Again, when it comes to locating this kind of information, don’t be shy about emailing a local sales representative. Although their primary goal is to sell you an instrument, it is in their best interest to be as helpful as possible so that you don’t purchase something that you will not be happy with.

Create a matrix of needs and wants.

Once you have collected enough information about each system, it is time to assemble everything in a tabular format for further comparison. By creating a matrix, you’ll be able to see the whole picture, which will help you identify value that is otherwise hidden when you consider only price or number of lasers and detectors. For example, one area that is often overlooked is the total cost of ownership, which, for some instruments, will be much more demanding of your operational budget than others. The total cost of ownership factors in not only consumables (such as quality control [QC] beads, sort-grade sheath fluid, and chip cartridges), which may add more than $25,000 to the purchase price over the life of the instrument, but also field support, including service costs and response time. Don’t forget to allow for the time investments associated with having to train new users and how that may affect your research progress. The matrix below can serve as an example.

* With the 100 μm chip.
** Consumables, service contract, setup time, training.

Take to social networks (being mindful of negative opinions).

Once you think you’ve narrowed down your choices to one or two instruments, it’s a good idea to check in with the various flow cytometry message boards in order to get user feedback. You should also reach out to colleagues and other labs for their experiences. Useful information that can come from the community includes whether they’re happy with their purchase, recurring hardware/software failures, maintenance issues, service issues, service response times, and cost of ownership. However, as with all message boards and customer reviews, bear in mind that the most dissatisfied users are usually the loudest. Even then, it is OK to bring any negative issues to the attention of the manufacturer (respecting the colleague’s confidentiality, of course) and ask for a response. While we’re all liable to assume that manufacturer representatives will be biased, they are professionals and will be up-front about any pros and cons. Get everything in writing — don’t rely on phone conversations. If you’re having trouble getting feedback, you can always go to the manufacturer’s site and look for customer testimonials.

Gain hands-on experience.

Finally, most people would never buy a car without taking it for a test drive first, and the same holds true when it comes to buying a cell sorter. So before taking the plunge on an instrument purchase, make sure to get a hands-on demonstration. Some of the things to look out for are setup time and how easy or difficult it is to learn to operate the system. This will be the same experience your users will have to go through. By running the instrument yourself, you can evaluate ease of use, software stability, and instrument performance (such as purity and sorting speeds), and you can get a feel for the user interface. Simply staining your favorite panel of antibodies and running them on the instrument will provide substantial information about how the instrument performs. You should note, though, that it may not be possible to run real samples during an instrument demo. Real samples often require more optimization than the company’s specialist has time for, especially if there are any biohazard considerations.