Enhancement of transient gene expression by fed-batch culture of HEK 293 EBNA1 cells in suspension

Xiangming Sun*, Peen Ern Goh, Kathy T K Wong, Tetsushi Mori, Miranda G S Yap

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


Enhanced green fluorescence protein (GFP) and erythropoietin (EPO) were used as reporters to assess and improve transient gene expression in HEK 293 EBNA1 cells. The production of EPO only lasted 3 days and reached 18.1 mg/l in suspension cultures in 1 l batch bioreactors. However, GFP expression examined in well-plate experiments persisted for 12 days in transfected cells but decreased rapidly within the next 15 days. These results suggest that the retaining of a plasmid in cells may not be a limiting factor for protein expression in large-scale transient transfection. To improve cell maintenance and protein expression, a fed-batch culture was performed using an enriched medium, a mixture of equal volumes of 293 SFM II medium and a 5 × amino acid solution prepared based on DMEM/F12 medium formula. EPO reached 33.6 mg/l, representing 86% increase over that of the batch culture. Moreover, the total amount of EPO produced was increased by 165% in view of the volume increase in the fed-batch culture. The serum-free medium used in this work enables cells growing well and transfection without medium change. Thus, the process reported here is simple and easy to scale up.

Original languageEnglish
Pages (from-to)843-848
Number of pages6
JournalBiotechnology Letters
Issue number11
Publication statusPublished - 2006 Jun
Externally publishedYes


  • HEK 293 EBNA1 cells
  • Polyethylenimine
  • Transient gene expression

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology
  • Microbiology
  • Bioengineering


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