alterlab-opentrons

name: alterlab-opentrons description: Writes liquid-handling protocols for Opentrons OT-2 and Flex robots using the official Opentrons Protocol API v2, with full access to v2 features for production-grade, officially compatible protocols. Use when authoring or running protocols specifically for Opentrons hardware. For multi-vendor automation or broader equipment control use pylabrobot instead. Part of the AlterLab Academic Skills suite. license: MIT allowed-tools: Read Write Edit Bash(curl:) Bash(python:) compatibility: Requires the opentrons Python package (pip install opentrons); protocols simulate locally via opentrons_simulate, execution needs an Opentrons OT-2 or Flex robot metadata: skill-author: AlterLab version: "1.0.0"

Opentrons Integration

Overview

Opentrons is a Python-based lab automation platform for Flex and OT-2 robots. Write Protocol API v2 protocols for liquid handling, control hardware modules (heater-shaker, thermocycler), manage labware, for automated pipetting workflows.

When to Use This Skill

This skill should be used when:

• Writing Opentrons Protocol API v2 protocols in Python
• Automating liquid handling workflows on Flex or OT-2 robots
• Controlling hardware modules (temperature, magnetic, heater-shaker, thermocycler)
• Setting up labware configurations and deck layouts
• Implementing complex pipetting operations (serial dilutions, plate replication, PCR setup)
• Managing tip usage and optimizing protocol efficiency
• Working with multi-channel pipettes for 96-well plate operations
• Simulating and testing protocols before robot execution

Core Capabilities

1. Protocol Structure and Metadata

Every Opentrons protocol follows a standard structure:

from opentrons import protocol_api

# Metadata
metadata = {
    'protocolName': 'My Protocol',
    'author': 'Name <email@example.com>',
    'description': 'Protocol description',
    'apiLevel': '2.19'  # Pin to a level your robot's app/firmware accepts
}

# Requirements (optional). When present, apiLevel here takes precedence over the
# value in metadata, and robotType is required for Flex.
requirements = {
    'robotType': 'Flex',  # or 'OT-2'
    'apiLevel': '2.19'
}

# Run function
def run(protocol: protocol_api.ProtocolContext):
    # Protocol commands go here
    pass

Key elements:

• Import protocol_api from opentrons
• Define metadata dict with protocolName, author, description, apiLevel
• Optional requirements dict for robot type and API version
• Implement run() function receiving ProtocolContext as parameter
• All protocol logic goes inside the run() function

2. Loading Hardware

Loading Instruments (Pipettes):

def run(protocol: protocol_api.ProtocolContext):
    # Load pipette on specific mount
    left_pipette = protocol.load_instrument(
        'flex_1channel_1000',  # Instrument name (Flex convention)
        'left',                # Mount: 'left' or 'right'
        tip_racks=[tip_rack]   # List of tip rack labware objects
    )

Common pipette load names (these are the exact instrument_name strings — do NOT invent p1000_single_flex-style names; Flex uses the flex_<channels>_<volume> convention):

• Flex: flex_1channel_50, flex_1channel_1000, flex_8channel_50, flex_8channel_1000, flex_96channel_1000
• OT-2: p20_single_gen2, p300_single_gen2, p1000_single_gen2, p20_multi_gen2, p300_multi_gen2

Loading Labware:

# Load labware directly on deck
plate = protocol.load_labware(
    'corning_96_wellplate_360ul_flat',  # Labware API name
    'D1',                                # Deck slot (Flex: A1-D3, OT-2: 1-11)
    label='Sample Plate'                 # Optional display label
)

# Load tip rack
tip_rack = protocol.load_labware('opentrons_flex_96_tiprack_1000ul', 'C1')

# Load labware on adapter
adapter = protocol.load_adapter('opentrons_flex_96_tiprack_adapter', 'B1')
tips = adapter.load_labware('opentrons_flex_96_tiprack_200ul')

Loading Modules:

# Temperature module (Flex + OT-2)
temp_module = protocol.load_module('temperature module gen2', 'D3')
temp_plate = temp_module.load_labware('corning_96_wellplate_360ul_flat')

# Heater-Shaker module (Flex + OT-2)
hs_module = protocol.load_module('heaterShakerModuleV1', 'D1')
hs_plate = hs_module.load_labware('corning_96_wellplate_360ul_flat')

# Thermocycler module (takes up specific slots automatically)
tc_module = protocol.load_module('thermocyclerModuleV2')
tc_plate = tc_module.load_labware('nest_96_wellplate_100ul_pcr_full_skirt')

# Magnetic Module (OT-2 ONLY) — an active, motorized module. Flex does not
# support it; on Flex use the unpowered Magnetic Block instead (see below).
mag_module = protocol.load_module('magnetic module gen2', '1')  # OT-2 numeric slot
mag_plate = mag_module.load_labware('nest_96_wellplate_100ul_pcr_full_skirt')

# Magnetic Block (Flex ONLY) — unpowered; labware is moved on/off it with the
# Gripper. There is no engage/disengage; it has no motors.
mag_block = protocol.load_module('magneticBlockV1', 'C2')
block_plate = mag_block.load_labware('nest_96_wellplate_100ul_pcr_full_skirt')

3. Liquid Handling Operations

Basic Operations:

# Pick up tip
pipette.pick_up_tip()

# Aspirate (draw liquid in)
pipette.aspirate(
    volume=100,           # Volume in µL
    location=source['A1'] # Well or location object
)

# Dispense (expel liquid)
pipette.dispense(
    volume=100,
    location=dest['B1']
)

# Drop tip
pipette.drop_tip()

# Return tip to rack
pipette.return_tip()

Complex Operations:

# Transfer (combines pick_up, aspirate, dispense, drop_tip)
pipette.transfer(
    volume=100,
    source=source_plate['A1'],
    dest=dest_plate['B1'],
    new_tip='always'  # 'always', 'once', or 'never'
)

# Distribute (one source to multiple destinations)
pipette.distribute(
    volume=50,
    source=reservoir['A1'],
    dest=[plate['A1'], plate['A2'], plate['A3']],
    new_tip='once'
)

# Consolidate (multiple sources to one destination)
pipette.consolidate(
    volume=50,
    source=[plate['A1'], plate['A2'], plate['A3']],
    dest=reservoir['A1'],
    new_tip='once'
)

Advanced Techniques:

# Mix (aspirate and dispense in same location)
pipette.mix(
    repetitions=3,
    volume=50,
    location=plate['A1']
)

# Air gap (prevent dripping)
pipette.aspirate(100, source['A1'])
pipette.air_gap(20)  # 20µL air gap
pipette.dispense(120, dest['A1'])

# Blow out (expel remaining liquid)
pipette.blow_out(location=dest['A1'].top())

# Touch tip (remove droplets on tip exterior)
pipette.touch_tip(location=plate['A1'])

Flow Rate Control:

# Set flow rates (µL/s)
pipette.flow_rate.aspirate = 150
pipette.flow_rate.dispense = 300
pipette.flow_rate.blow_out = 400

4. Accessing Wells and Locations

Well Access Methods:

# By name
well_a1 = plate['A1']

# By index
first_well = plate.wells()[0]

# All wells
all_wells = plate.wells()  # Returns list

# By rows
rows = plate.rows()  # Returns list of lists
row_a = plate.rows()[0]  # All wells in row A

# By columns
columns = plate.columns()  # Returns list of lists
column_1 = plate.columns()[0]  # All wells in column 1

# Wells by name (dictionary)
wells_dict = plate.wells_by_name()  # {'A1': Well, 'A2': Well, ...}

Location Methods:

# Top of well (default: 1mm below top)
pipette.aspirate(100, well.top())
pipette.aspirate(100, well.top(z=5))  # 5mm above top

# Bottom of well (default: 1mm above bottom)
pipette.aspirate(100, well.bottom())
pipette.aspirate(100, well.bottom(z=2))  # 2mm above bottom

# Center of well
pipette.aspirate(100, well.center())

5. Hardware Module Control

Temperature Module:

# Set temperature
temp_module.set_temperature(celsius=4)

# Wait for temperature
temp_module.await_temperature(celsius=4)

# Deactivate
temp_module.deactivate()

# Check status
current_temp = temp_module.temperature  # Current temperature
target_temp = temp_module.target  # Target temperature

Magnetic Module (OT-2 only):

The active Magnetic Module exists only on the OT-2. On the Flex, use the unpowered Magnetic Block (magneticBlockV1), which has no engage/disengage — labware is moved on and off it with the Gripper.

# Engage (raise magnets)
mag_module.engage(height_from_base=10)  # mm from labware base

# Disengage (lower magnets)
mag_module.disengage()

# Check status
is_engaged = mag_module.status  # 'engaged' or 'disengaged'

Heater-Shaker Module:

# Set temperature
hs_module.set_target_temperature(celsius=37)

# Wait for temperature
hs_module.wait_for_temperature()

# Set shake speed
hs_module.set_and_wait_for_shake_speed(rpm=500)

# Close labware latch
hs_module.close_labware_latch()

# Open labware latch
hs_module.open_labware_latch()

# Deactivate heater
hs_module.deactivate_heater()

# Deactivate shaker
hs_module.deactivate_shaker()

Thermocycler Module:

# Open lid
tc_module.open_lid()

# Close lid
tc_module.close_lid()

# Set lid temperature
tc_module.set_lid_temperature(celsius=105)

# Set block temperature
tc_module.set_block_temperature(
    temperature=95,
    hold_time_seconds=30,
    hold_time_minutes=0.5,
    block_max_volume=50  # µL per well
)

# Execute profile (PCR cycling)
profile = [
    {'temperature': 95, 'hold_time_seconds': 30},
    {'temperature': 57, 'hold_time_seconds': 30},
    {'temperature': 72, 'hold_time_seconds': 60}
]
tc_module.execute_profile(
    steps=profile,
    repetitions=30,
    block_max_volume=50
)

# Deactivate
tc_module.deactivate_lid()
tc_module.deactivate_block()

Absorbance Plate Reader (Flex):

# Load (lid must be closed to initialize, open to load/read labware)
plate_reader = protocol.load_module('absorbanceReaderV1', 'D3')

# Initialize: wavelengths are set here, NOT on read()
plate_reader.close_lid()
plate_reader.initialize('multi', [450, 650])  # 'single' or 'multi'
plate_reader.open_lid()

# Read the loaded plate (returns a dict keyed by wavelength)
result = plate_reader.read()

6. Liquid Tracking and Labeling

Define Liquids:

# Define liquid types
water = protocol.define_liquid(
    name='Water',
    description='Ultrapure water',
    display_color='#0000FF'  # Hex color code
)

sample = protocol.define_liquid(
    name='Sample',
    description='Cell lysate sample',
    display_color='#FF0000'
)

Load Liquids into Wells:

# Load liquid into specific wells
reservoir['A1'].load_liquid(liquid=water, volume=50000)  # µL
plate['A1'].load_liquid(liquid=sample, volume=100)

# Mark wells as empty
plate['B1'].load_empty()

7. Protocol Control and Utilities

Execution Control:

# Pause protocol
protocol.pause(msg='Replace tip box and resume')

# Delay
protocol.delay(seconds=60)
protocol.delay(minutes=5)

# Comment (appears in logs)
protocol.comment('Starting serial dilution')

# Home robot
protocol.home()

Conditional Logic:

# Check if simulating
if protocol.is_simulating():
    protocol.comment('Running in simulation mode')
else:
    protocol.comment('Running on actual robot')

Rail Lights (Flex only):

# Turn lights on
protocol.set_rail_lights(on=True)

# Turn lights off
protocol.set_rail_lights(on=False)

8. Multi-Channel and 8-Channel Pipetting

When using multi-channel pipettes:

# Load 8-channel pipette
multi_pipette = protocol.load_instrument(
    'p300_multi_gen2',
    'left',
    tip_racks=[tips]
)

# Access entire column with single well reference
multi_pipette.transfer(
    volume=100,
    source=source_plate['A1'],  # Accesses entire column 1
    dest=dest_plate['A1']       # Dispenses to entire column 1
)

# Use rows() for row-wise operations
for row in plate.rows():
    multi_pipette.transfer(100, reservoir['A1'], row[0])

9. Common Protocol Patterns

Serial Dilution:

def run(protocol: protocol_api.ProtocolContext):
    # Load labware
    tips = protocol.load_labware('opentrons_flex_96_tiprack_200ul', 'D1')
    reservoir = protocol.load_labware('nest_12_reservoir_15ml', 'D2')
    plate = protocol.load_labware('corning_96_wellplate_360ul_flat', 'D3')

    # Load pipette
    p300 = protocol.load_instrument('flex_1channel_1000', 'left', tip_racks=[tips])

    # Add diluent to all wells except first
    p300.transfer(100, reservoir['A1'], plate.rows()[0][1:])

    # Serial dilution across row
    p300.transfer(
        100,
        plate.rows()[0][:11],  # Source: wells 0-10
        plate.rows()[0][1:],   # Dest: wells 1-11
        mix_after=(3, 50),     # Mix 3x with 50µL after dispense
        new_tip='always'
    )

Plate Replication:

def run(protocol: protocol_api.ProtocolContext):
    # Load labware
    tips = protocol.load_labware('opentrons_flex_96_tiprack_1000ul', 'C1')
    source = protocol.load_labware('corning_96_wellplate_360ul_flat', 'D1')
    dest = protocol.load_labware('corning_96_wellplate_360ul_flat', 'D2')

    # Load pipette
    p1000 = protocol.load_instrument('flex_1channel_1000', 'left', tip_racks=[tips])

    # Transfer from all wells in source to dest
    p1000.transfer(
        100,
        source.wells(),
        dest.wells(),
        new_tip='always'
    )

PCR Setup:

def run(protocol: protocol_api.ProtocolContext):
    # Load thermocycler
    tc_mod = protocol.load_module('thermocyclerModuleV2')
    tc_plate = tc_mod.load_labware('nest_96_wellplate_100ul_pcr_full_skirt')

    # Load tips and reagents
    tips = protocol.load_labware('opentrons_flex_96_tiprack_200ul', 'C1')
    reagents = protocol.load_labware('opentrons_24_tuberack_nest_1.5ml_snapcap', 'D1')

    # Load pipette
    p300 = protocol.load_instrument('flex_1channel_1000', 'left', tip_racks=[tips])

    # Open thermocycler lid
    tc_mod.open_lid()

    # Distribute master mix
    p300.distribute(
        20,
        reagents['A1'],
        tc_plate.wells(),
        new_tip='once'
    )

    # Add samples (example for first 8 wells)
    for i, well in enumerate(tc_plate.wells()[:8]):
        p300.transfer(5, reagents.wells()[i+1], well, new_tip='always')

    # Run PCR
    tc_mod.close_lid()
    tc_mod.set_lid_temperature(105)

    # PCR profile
    tc_mod.set_block_temperature(95, hold_time_seconds=180)

    profile = [
        {'temperature': 95, 'hold_time_seconds': 15},
        {'temperature': 60, 'hold_time_seconds': 30},
        {'temperature': 72, 'hold_time_seconds': 30}
    ]
    tc_mod.execute_profile(steps=profile, repetitions=35, block_max_volume=25)

    tc_mod.set_block_temperature(72, hold_time_minutes=5)
    tc_mod.set_block_temperature(4)

    tc_mod.deactivate_lid()
    tc_mod.open_lid()

Best Practices

1. Always specify API level: Pin a stable apiLevel your robot's app/firmware supports (run opentrons_simulate to confirm); do not blindly use a number higher than the robot accepts
2. Use meaningful labels: Label labware for easier identification in logs
3. Check tip availability: Ensure sufficient tips for protocol completion
4. Add comments: Use protocol.comment() for debugging and logging
5. Simulate first: Always test protocols in simulation before running on robot
6. Handle errors gracefully: Add pauses for manual intervention when needed
7. Consider timing: Use delays when protocols require incubation periods
8. Track liquids: Use liquid tracking for better setup validation
9. Optimize tip usage: Use new_tip='once' when appropriate to save tips
10. Control flow rates: Adjust flow rates for viscous or volatile liquids

Troubleshooting

Common Issues:

• Out of tips: Verify tip rack capacity matches protocol requirements
• Labware collisions: Check deck layout for spatial conflicts
• Volume errors: Ensure volumes don't exceed well or pipette capacities
• Module not responding: Verify module is properly connected and firmware is updated
• Inaccurate volumes: Calibrate pipettes and check for air bubbles
• Protocol fails in simulation: Check API version compatibility and labware definitions

Resources

For detailed API documentation, see references/api_reference.md in this skill directory.

For example protocol templates, see scripts/ directory.