- Gentamicin is a broad-spectrum aminoglycoside antibiotic widely used in cell culture to prevent or control bacterial contamination, particularly from Gram-negative organisms. It acts by binding to the 30S subunit of bacterial ribosomes, disrupting protein synthesis and causing misreading of mRNA, which ultimately results in bacterial cell death. Gentamicin is active against a broad range of both Gram-negative and some Gram-positive bacteria, making it especially valuable in tissue culture settings where contamination risks are high, such as with primary cell cultures or complex media.
- In contrast to penicillin and streptomycin, gentamicin has a longer half-life in culture media, and it retains its activity under a broader range of temperatures and pH conditions. This stability makes it useful during extended incubation periods or in environments where contamination risk is elevated. It is typically used in cell culture at concentrations of 10–50 µg/mL, depending on the cell type and level of contamination risk.
- Gentamicin is generally well tolerated by most mammalian cells at standard working concentrations. However, like other aminoglycosides, it may exert off-target effects in sensitive cells, particularly under prolonged exposure or high concentrations. There is some potential for interference with mitochondrial protein synthesis, as mitochondrial ribosomes resemble bacterial ribosomes. Nevertheless, at standard concentrations and under proper culture conditions, such effects are typically minimal.
- Importantly, while gentamicin is effective in reducing contamination, its use should not replace good aseptic technique. Overreliance on antibiotics can mask poor lab practices and lead to the emergence of resistant bacterial strains. Therefore, gentamicin is best used as a preventive measure during high-risk procedures or as a short-term solution to manage contamination, rather than as a permanent additive in long-term cultures.
