Monitoring of Metal Elements in Cell Culture Supernatant using Atomic Absorption Spectrophotometer

Importance of the Topic

The concentration of metal ions in cell culture supernatants impacts key cellular processes, including metabolic pathways and antibody glycosylation. Reliable monitoring of trace and bulk elements ensures consistent product quality in biopharmaceutical manufacturing.

Objectives and Study Overview

This study evaluated a simplified sample pretreatment and analysis protocol using atomic absorption spectroscopy to quantify Zn, Mg, Cu, Mn, Co, and Fe in Chinese hamster ovary (CHO) cell culture supernatants over a four-day culture period.

Methodology and Instrumentation

Sample Preparation:

• Shake culture of CHO cells in 125 mL flasks (120 rpm) over 4 days
• Daily collection of 1 mL culture medium followed by centrifugation (5 min, 4 °C)
• Supernatant diluted in 0.07 M HNO₃ (0.5 v/v %) for each element
• Calibration by diluting 1000 mg/L standard solutions in the same acid matrix

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Main Results and Discussion

Flame Method (Zn, Mg):

• Zn declined from 5.2 to 4.1 mg/L (days 0–4)
• Mg ranged 53–47 mg/L with low RSD (<1 %)

Electric Thermal Method (Cu, Mn, Co, Fe):

• Cu increased to ~24 µg/L; Mn rose to 17 µg/L; Co ~268 µg/L; Fe ~409 µg/L (day 3 peaks)
• Precision RSD <7 %; recovery rates 86–120 %
• Mn peak shape varied in matrix, requiring area-based integration

Benefits and Practical Applications

This approach enables rapid quantification across a wide dynamic range (ppb to tens of ppm) with minimal pretreatment. It is suited for routine quality control, process monitoring, and research in bioprocess development.

Future Trends and Potential Applications

Emerging directions include integration into process analytical technology (PAT) platforms for real-time monitoring, automation and high-throughput autosampling, development of miniaturized AAS sensors, and hybrid techniques combining AAS with complementary spectroscopies.

Conclusion

Atomic absorption spectroscopy with simple dilution pretreatment provides accurate, precise, and broad-range monitoring of essential metal elements in cell culture supernatants, supporting consistent antibody production quality.

Reference

• Inn H. Yuk et al., Effects of copper on CHO cells: Insights from gene expression analyses, Biotechnology Progress, 2014
• Prabhu et al., Zinc supplementation decreases galactosylation of recombinant IgG in CHO cells, Applied Microbiology and Biotechnology, 2018
• Shimadzu Application News A634, Direct Analysis of Metallic Elements in Cell Culture Medium by Atomic Absorption Spectrophotometry