MaxCyte Platform > Technology > Technology Basics

MaxCyte transfection technology is based on the general principles of electroporation, which involves the application of an electric field to a cell suspension, causing the cell membrane to become transiently permeable and encouraging external material to enter the cell. MaxCyte has leveraged this fundamental property of cells -- reversible permeability in the presence of electrical charge -- to develop a patented, fully-scalable electroporation technology that has been demonstrated to be simple, highly controlled and flexible. By safely and repeatedly inserting nearly any molecule, including genes, proteins, DNA or RNA, into any target cell, without the use of added biological or chemical agents, MaxCyte electroporation enables transfection of a wide range of cells with loading efficiencies exceeding 90%. The technology is highly scalable from 5x105 cells in seconds using small-scale, static electroporation to 1x1010 cells in less than 30 minutes using flow electroporation. MaxCyte scalable electroporation has been successfully applied in ex vivo cell therapy, protein production and drug discovery pipelines where reproducibility, efficiency and the need for increased cell numbers are critical.


Why is MaxCyte Electroporation Unique?

Transfect up to 1x1010 cells using flow electroporation

The MaxCyte system can perform small and large-scale electroporation using a single instrument and a single electroporation protocol. Static electroporation is the term used for small scale electroporation in which cells and the material(s) to be transfected are mixed and placed into a small processing chamber that is then loaded into the instrument for electroporation.

Flow Electroportation Flow electroporation is the term used for large-scale electroporation in which cells and the material(s) to be transfected are mixed and placed into the source bag of a large-scale processing assembly. The sterile processing assembly is then loaded onto the MaxCyte instrument. When cell processing begins, 3 mL fractions flow in succession through the electroporation chamber and continue into the cell collection bag. Up to 1x1010 cells can be transfected in less than 30 minutes using flow electroporation. Transfected cells can be used immediately following a 20 minute recovery period or cryopreserved for later use.
To demonstrate the consistency of flow electroporation throughout a large-scale run, cells were transfected via flow electroporation and fractions were collected throughout the run (Figure 1). The transfection efficiency, as measured by GFP expression, and cell viability were consistent throughout flow electroporation of 6x109 cells. The average large scale transfection performance was also compared to results from a single, small scale transfection of 4x107 cells using static electroporation and found to be similar.

Precision Transfection using Flow Electroporation
Figure 1. Precision Transfection using Flow Electroporation. 6x109 K562 cells were transfected with pGFP DNA using flow electroporation and the K562 pre-loaded electroporation protocol. 28 fractions throughout the transfection process were collected and analyzed 24 hrs post transfection for cell viability (% cells excluding propidium iodide) and transfection efficiency (% GFP+ cells). A single, small scale transfection of 4x107 cells using static electroporation was performed.

Transfecting cells using MaxCyte electroporation

MaxCyte instruments are supplied with pre-loaded electroporation protocols optimized for a wide range of cell types which simplifies assay development and maximizes transfection performance and reproducibility. Identical electroporation parameters and cell handling are used for small and large-scale electroporation enabling streamlined scale up to high throughput transfection. MaxCyte transient transfection is completed in three easy steps: cell harvesting, electroporation, and post electroporation cell usage.

Cell Preparation
Cells are harvested from culture using standard methods and suspended at high density (typically 1x107- 1x108 cells/mL) in MaxCyte Electroporation Buffer, a physiologically balanced salt solution that contains no biological agents. The same buffer formulation is used for all cell types.
Cell Preparation
Cell Electroporation
Cells are mixed with loading agents (DNA, RNA, protein, etc.) and transferred to sterile, single use processing assemblies (PAs). Cells can be transfected with multiple types and combinations of loading agents, including DNA, mRNA, siRNA, proteins and small molecules. Small scale transfections (5x105-4x107 cells) are performed by static electroporation in OC-100 and OC-400 PAs; large scale transfections (up to 1x1010 cells) are performed by flow electroporation in CL-2 PAs. MaxCyte instruments come loaded with a variety of electroporation protocols that are optimized for individual cell types; users do not need to make any adjustments to the electrical parameters. The user transfers the PA to the instrument, selects the appropriate protocol and PA type, and clicks the start icon on the computer.
Cell Electroporation
Post Electroporation Cell Handling
After electroporation, cells are transferred from the PA to a sterile, multi-well dish (for OC-100/400s) or T-flask (for CL-2s) and allowed to recover for 20 minutes at 37°C. The cells are suspended in standard cell culture medium and either plated for immediate use in cellular assays or cryopreserved for future use. MaxCyte has developed several cryopreservation protocols that enable cell archiving while maximizing cell viability and target expression upon thawing. Post Electroporation Cell Handling

High efficiency transfection using pre-loaded cell-type specific electroporation protocols

MaxCyte transfection efficiencies are routinely greater than 90% and cell viability greater than 90% (Figure 2). MaxCyte technology causes minimal off-target perturbations of gene expression, resulting in assays with higher fidelity and improved efficiency. MaxCyte instruments enable transfection of a variety of cell lines, historically difficult-to-transfect cells, primary cells, and stem cells using preprogrammed electroporation protocols. Standard electroporation protocols provide an optimal blend of loading efficiency and cell viability. MaxCyte scientists have developed additional protocols for CHO and HEK cells that are designed specifically for high level protein expression. There are currently over 30 different electroporation protocols and our list is continually expanding. MaxCyte scientists are available to consult with clients to identify the most appropriate protocol for any cell type.

High Efficiency, High Viability Transfection.
Figure 2. High Efficiency, High Viability Transfection. Ten different cell types were transfected using MaxCyte electroporation with 200μg/ml pGFP DNA using the appropriate pre-loaded protocol. 24 hrs post transfection cells were examined for cell viability (% cells excluding propidium iodide) and transfection efficiency (% GFP+ cells).
Current MaxCyte Electroporation Protocols
CHO Jurkat Hep G2 U2OS RBL COS-7
Hela K562 CV-1 SH-Sy5y Neuro2a LNCaP
HEK 293 NIH 3T3 THP-1 COS-1 NSO DLD-1
Huh-7 Renca Min-6 A549 C6 C2C12
Primary Fibroblasts Vero Panc-1 PC-3 CaCo-2  
Mesenchymal Stem Cells PC12 L5278Y BHK-21 RLE  

MaxCyte electroporation is compatible with regulatory guidelines

For a cell modification technology to be clinically relevant, it must be capable of transfecting large numbers of cells in a sterile system with consistently high efficiency and cell viability in a way that can be integrated within cGMP production standards. MaxCyte electroporation provides unparalleled consistency, scalability, and loading efficiency while avoiding the inherent safety drawbacks of alternative methods such as viral vectors and chemical transfection reagents. MaxCyte technology avoids common cell loading challenges and provides an approach that dramatically accelerates clinical development timelines by avoiding toxicity associated with other methods of cell modificationdue to its inherent simplicity and safety. As an example, one MaxCyte partner was able to submit an IND at least six months earlier than anticipated. MaxCyte's clinical-grade cell loading technology is fully developed and well validated, with an FDA Master File in place and RAC cleared.