Agilent Bravo Automated Liquid Handling Platform: 96-Channel 10 μL Tip Accuracy and Precision

Significance of the Topic

The ability to dispense very small liquid volumes with high accuracy and precision is critical in modern analytical laboratories.
Automated platforms reduce human error, increase throughput and reproducibility, and support diverse applications ranging from genomic assays to compound screening.

Objectives and Overview of the Study

This study aimed to evaluate the performance of the Agilent Bravo automated liquid handling system equipped with a 96-channel small transfer (ST) disposable tip head and 10 µL tips at low volumes (0.3 µL to 2 µL).
The primary goals were to quantify accuracy (difference between target and delivered volume) and precision (coefficient of variation) at the lower end of the practical dispensing range.

Methodology

The assay used tartrazine dye in DMSO as a tracer, dispensing defined volumes into dry microplate wells followed by dilution with water and absorbance measurement at 405 nm.
Key steps:

1. Load 60 mL of 0.25% (w/v) tartrazine in DMSO into a manual fill reservoir on the Bravo deck.
2. Attach 10 µL disposable tips to the 96-channel ST head.
3. Aspirate and dispense 0.3, 0.5 or 2 µL into each quadrant of a 384-well plate using defined pre-aspirate and blow-out volumes.
4. Add water to reach 50 µL total volume, centrifuge plates at 1800 rpm for 60 s.
5. Measure absorbance at 405 nm to calculate delivered volumes via a pre-established calibration curve.

Used Instrumentation

• Agilent Bravo Automated Liquid Handling Platform with nine deck positions
• 96-channel ST disposable tip head, 10 µL tips (Part No. 10734-202)
• Manual fill reservoir, 96-well (Part No. 08105-001)
• 384-well flat-bottom polystyrene microplates (Greiner 781101)
• UV/Vis spectrophotometer with 405 nm filter

Results and Discussion

Performance metrics at low volumes:

• 0.3 µL: precision = 3.1% CV; accuracy = ±1.5%; ≈7% of wells outside ±5% range
• 0.5 µL: precision = 2.3% CV; accuracy = ±0.8%; ≈3% of wells outside ±5% range
• 2.0 µL: precision = 1.1% CV; accuracy = ±0.8%; no outliers beyond ±5%

Transfer time per 384-well plate ranged from 24 to 27 s depending on volume.
Overall, the system met or exceeded a CV of 5% and accuracy within ±10% across the tested range.

Benefits and Practical Applications

The platform’s ability to reliably dispense sub-microliter volumes supports demanding workflows in:

• High-throughput screening and compound management
• Genomic and proteomic assays requiring low-volume reagents
• Cell plating and cell-based assays under laminar flow conditions
• Quality control environments with tight tolerance requirements

Future Trends and Opportunities

Advances in microfluidics, integration of real-time monitoring sensors and adaptive control algorithms are expected to further improve low-volume dispensing.
Development of new tip materials and head configurations may extend the range and chemical compatibility.
Integration with laboratory information management systems (LIMS) will enhance data traceability and workflow automation.

Conclusion

The Agilent Bravo platform with the 96-channel ST head and 10 µL tips delivers precise, accurate and rapid low-volume dispensing suitable for a broad spectrum of analytical and screening applications.
Its modular deck and compatibility with various labware make it a versatile tool for modern automated laboratories.

References

1. Holman JW, Mifflin TE, Felder RA, Demers LM. Evaluation of an automated preanalytical robotic workstation at two academic health centers. Clin Chem. 2002 Mar;48(3):540-8.