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FACS, MACS, and BACS™: What’s the Difference?

Updated on Feb 15, 2024 By Jason Ellis, PhD

scientists separating cells in a research lab

In the fast-evolving world of biomedical research, the ability to accurately classify and analyze cells is pivotal. Cell isolation and sorting technologies provide essential tools for researchers in several prominent fields, including immunology, cancer research, and stem cell studies. 

Among the most prominent techniques are fluorescence-activated cell sorting (FACS), magnetic-activated cell sorting (MACS), and the emerging buoyancy-activated cell sorting (BACS™). Each of these methods has unique advantages and challenges, shaping how researchers isolate and study cells.

FACS (Fluorescence-Activated Cell Sorting)

FACS is a subset of advanced flow cytometry techniques, a technology widely used in biological research to differentiate cells based on physical characteristics like size and phenotype. 

Principle and Process

FACS uses fluorophores to label cells. These small fluorescent molecule tags are often conjugated to antibodies that recognize specific antigens on the cell surfaces. The labeled cells are then identified and sorted based on the color of their fluorescence tags when excited by a light source. This process allows for the precise analysis of cell populations, identifying cells based on specific markers.

Applications and Advantages

Widely used in research involving hematopoiesis, oncology, and stem cell research, FACS is celebrated for its versatility. Adding the ability to physically separate individual cells to the already powerful tools of flow cytometry enables researchers to sort cells based on surface markers and physical characteristics like size and granularity.


One major drawback of FACS is its time-intensive nature, often requiring several hours for large samples. Additionally, the equipment is expensive and difficult to maintain, requiring highly skilled personnel to operate. The extensive fluidic systems require a higher sample volume than other techniques, and the reuse of tubing and equipment increases the risk of contamination when not perfectly cleaned between runs. 

MACS (Magnetic-Activated Cell Sorting)

MACS leverages magnetic fields to facilitate cell sorting, offering a rapid alternative to traditional FACS and flow cytometry methods. 

Principle and Process

This method uses magnetic microbeads conjugated with antibodies specific to certain cell antigens. The targeted cells are magnetized to the column matrix, while non-targeted cells flow through the sample column.

Applications and Advantages

MACS is known for its speed and consistency, especially in processes where quick cell separation is crucial. It’s commonly used for isolating a particular cell type from a mixed population.


The process can be harsh on delicate cells, potentially affecting their viability. The cost of the magnetic beads and separation columns can also be significant.

BACS™ (Buoyancy-Activated Cell Sorting):

BACS™ is the innovative and gentle proprietary approach to cell separation developed by Akadeum Life Sciences. 

Principle and Process

BACS™ uses buoyancy-activated microbubbles. These microbubbles bind to targeted cell antigens, enabling their separation based on buoyancy rather than magnetic or fluorescent properties.

Unique Advantages

BACS™ is gentle on cells, preserving their integrity and viability. It’s also cost-effective and fast, typically completing cell sorting in 30-60 minutes without requiring expensive, specialized equipment.

Broad Applications

BACS™ is adaptable for various protocols and cell populations, including cell enrichment for immunology, leukopak processing, optimizing sample prep for flow cytometry, and customized streptavidin workflows. 

Technology: Fluorescence-based sortingMagnetic bead-based sortingBuoyancy-based microbubble sorting
Cell Handling:Can be harsh on cells and induce apoptosisHarsh on membranes of delicate cellsUniversally gentle on cells
Time:2+ hours30+ minutes30-60 minutes
Cost:High: Equipment and extensive upkeepMiddle: Equipment costs and consumablesLow: No special equipment needed
Versatility:Multiplexed labeling, can also sort size and granularityAdaptable to various targetsAdaptable to various targets and assays
Sample Integrity:Risk of cross-contaminationGenerally reliableHigh integrity and viability
  1. Efficiency and time-saving: In a research environment where time is of the essence, BACS™ offers an unparalleled advantage. With cell sorting completed within 30-60 minutes, BACS™ dramatically outpaces FACS, enabling researchers to conduct more experiments in less time.
  2. Cost-effectiveness: Unlike its predecessors, BACS™ does not require expensive machinery or consumables. This cost advantage makes it an accessible option for a wider range of laboratories, especially those with budget constraints.
  3. Gentleness on cells: One of the most striking benefits of BACS™ is its gentle approach to cell sorting. This method ensures sorted cells’ high viability and integrity, which is crucial in sensitive applications and when working with fragile cells.
  4. Ease of use: BACS™ simplifies cell sorting, making it user-friendly and less technically demanding. This accessibility opens doors for researchers who may not have specialized training in cell isolation technologies or maintenance of complex instrumentation.
  5. Versatility: The adaptability to various applications and cell populations adds another layer to the superiority of  BACS™. Whether for routine cell sorting or specialized research, it proves to be an effective tool.

How to Incorporate BACS™ Into Your Research

Take advantage of BACS™ proven ability to isolate cells and reduce sorting time. Here are just a few ideas:

  • Gentle incubation with microbubbles: BACS™ uniquely allows cells to be gently incubated with microbubbles. Skip the harsh environments of flow cytometers and magnetic columns. This is especially beneficial for delicate cell populations that are prone to damage.
  • Enable negative selection and clean up samples with ease: BACS™ offers an efficient and effective negative selection process without the need for magnetic microbeads. This not only simplifies the procedure but also reduces the risk of physical or chemical stress on the cells. This process can even be used to clean up samples by removing dead and dying cells or red blood cell contamination. 
  • Adaptability to various cell types and protocols: BACS™ caters to a wide range of research needs. Its gentle process makes it suitable for various cell populations, including delicate primary cells, stem cells, and rare cell populations, which are often challenging to isolate without compromising their integrity. BACS™ is also adaptable to numerous protocols. It can be effectively used in immunological assays, cancer research, and a wide variety of other areas of cellular research.

Akadeum Stands at the Forefront of Cell Sorting Technology

The evolution of cell sorting technologies from FACS and MACS to BACS™ represents a significant stride in biomedical research. The ability of BACS™ to handle diverse cells and samples without the need for specialized equipment or extensive sample preparation enhances its appeal in both academic and clinical research settings. This versatility ensures that BACS™ is more than just an alternative to existing methods—it’s also a comprehensive solution for a variety of cell sorting challenges

Akadeum encourages researchers and laboratories to explore the benefits of BACS™. By adopting this innovative technology, you can enhance the quality and efficiency of your cell sorting processes while minimizing costs and technical challenges. 

Experience the future of cell sorting with Akadeum’s buoyancy-activated cell sorting technology. Contact us for more information, or try our products today to revolutionize your research endeavors.

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