Improving Long-Term Compound Storage in I.DOT Source Plates

In drug discovery and other types of applied research, maintaining compound stability is critical for obtaining accurate and reproducible results. Degradation, evaporation, or precipitation can compromise experiments, making effective storage solutions a necessity.

Our latest application note, Evaluation of Compound Storage Efficacy in DISPENDIX I.DOT HT and S Source Plates at -20°C and Room Temperature, is in collaboration with our customer, The Cultivated B, where we evaluate the efficacy of I.DOT HT and I.DOT S source plates in preserving compounds under various conditions—shedding light on the best practices for long-term storage.

The Challenge of Compound Storage

When storing compounds for extended periods, temperature fluctuations and exposure to oxygen or moisture can significantly impact stability. An unstable compound can lead to inconsistent dose-response curves, affecting the reliability of experimental data. That’s why choosing the right storage environment is as crucial as selecting the right compounds.

The I.DOT Non-Contact Dispenser Advantage

The DISPENDIX I.DOT Non-Contact Dispenser is a precision liquid handler capable of dispensing volumes as low as 2.55 nL with a resolution of 0.1 nL. Equipped with optical volume verification, it ensures precise dosing every time.

Available in multiple formats—including the I.DOT S with 96-well source plates and the I.DOT HT with 384-well source plates—this system is optimized for high-throughput screening and compound management.

Putting I.DOT Source Plates to the Test

To assess the ability of I.DOT HT and I.DOT S source plates to maintain compound integrity, a two-month study was conducted. Compounds were stored in different environments:

• -20°C in StoragePod (a system designed to minimize oxygen and moisture exposure)
• -20°C in a dry air environment (silica gel in an airtight container)
• Room Temperature (RT) in StoragePod
• Room Temperature (RT) in a dry air environment

Cell viability and growth assays were then performed to evaluate the compounds’ effectiveness over time.

Key Findings: Temperature Matters

The results highlighted the importance of proper storage conditions:

• Best Storage Condition: Plates stored at -20°C in both StoragePod and dry air environments retained their integrity, with dose-response curves showing a high correlation to freshly prepared compounds (Fig. 1).
• Room Temperature Risks: Compounds stored at RT showed signs of degradation, with those in the dry air environment exhibiting significant dose-response variability and lower cell viability (Fig. 2).
• StoragePod vs. Dry Air: At -20°C, both systems performed well. However, at RT, the StoragePod provided better protection than the dry air environment, though moderate degradation was still observed.

Figure 1. Dose-response curves (top) and time point correlation determination (bottom) showing the effectiveness of the I.DOT HT in maintaining compound stability after 2 months at -20°C. (N=4)

Figure 2. Dose-response curves (top) and time point correlation determination (bottom) showing compound degradation when stored at RT. (N=4)

Ensuring Accurate Dispensing

Beyond storage, maintaining dispensing accuracy is another critical factor. The I.DOT system’s droplet detection technology helped assess dispensing efficiency. Compounds stored at RT in a dry air environment frequently clogged dispensing nozzles, leading to inconsistent droplet formation. In contrast, those stored at -20°C showed minimal dispensing issues, reinforcing the importance of cold storage (Fig. 3).

Figure 3. Dispensing evaluation of (a) the I.DOT HT and (b) the I.DOT S showing mostly effective dispensing of compounds stored at -20°C, except for some randomly distributed misses and multiple misses when compounds are stored at RT.

Key Takeaways for Researchers

For laboratories and researchers working with sensitive compounds, these findings offer clear guidance:

• For long-term storage, always opt for -20°C to maintain compound stability (Fig. 2).
• If RT storage is necessary, use a controlled atmosphere like StoragePod to minimize degradation.
• Pair proper storage with precise dispensing technology like the I.DOT Non-Contact Dispenser to ensure reproducible results.

By implementing the right storage and dispensing solutions, scientists can maximize compound integrity and obtain reliable, high-quality data in drug discovery and screening workflows.

Download the full application note or schedule a workflow consultation with a science-first DISPENDIX product specialist now!