Opto-Fluidic Solutions
Neuroscience research increasingly leverages advanced tools for manipulating and monitoring neural activity with high precision. Among these techniques, controlled intracranial fluid injection is a widely used approach in both head-fixed and freely moving mice. Researchers widely use fluid injection to deliver a broad range of agents directly into specific brain regions, including viral vectors, metabolites (e.g., glucose, cAMP, ATP), neurotransmitters, synaptic receptor agonists and antagonists (e.g., NMDA, bicuculline).
This is essential for numerous neuroscience applications, including:
- Neuropharmacology: Studying the effects of drugs on specific brain circuits.
- Circuit Neuroscience: Modulating neuronal activity to study functional connectivity and behavior.
- Disease Modeling: Delivering disease-associated proteins, toxins, or therapeutic candidates to create and study models of neurological disorders.
- Lesion and Ablation Studies: Producing localized lesions to investigate the function of specific brain structures.
- Biosensor development: Delivering known concentrations of analytes or neuromodulators to validate biosensor sensitivity and response (e.g., injecting oxytocin to validate GRAB-Ox).
- Self-administration: Allowing animals to control fluid delivery during behavioral and fiber photometry experiments.
At Doric Lenses Inc., we provide solutions for intracranial fluid delivery combined with optical neural recording and stimulation, enabling researchers to perform multiple experimental applications:
- Fluid delivery + Opsin excitation:
Localized fluid delivery combined with opsin excitation for experiments involving optogenetics, uncaging or other photoactivatable molecules. - Fluid delivery + Fiber Photometry: Fluid delivery directly at the site of photometry recording, ideal for validating and characterizing new biosensors while monitoring neural signals.
- Fluid delivery + Miniscope Imaging: Localized fluid delivery combined with single-cell calcium imaging, enabling researchers to examine how targeted pharmacological or molecular manipulations affect neuronal activity.
Here we provide an overview of our solutions, highlighting their key features, and compatibility with a wide range of experimental applications.
Opto-Fluidic Cannula
Opto-Fluidic Cannulas are designed for experiments that combine fluid delivery with optogenetics or fiber photometry
When targeting a single brain site, researchers can choose between two configurations depending on their experimental needs:
- iOFC Cannula: Ideal when fluid delivery and optical manipulation are performed in separate sessions. A single cannula is implanted, while interchangeable fluidic and optical connectors can be used for each session.
- OMFC Cannula: Required when fluid delivery and optical manipulation need to occur simultaneously at the same brain site. It provides two separate paths, allowing fluid injection and optical manipulation in parallel.
The different Doric Opto-Fluid Cannulas, their intended applications, and compatible accessories (cannula holder, and injector) are listed below.
Optofluid Cannula with interchangeable injectors (iOFC)
- Ideal for single site targeting
- Allows either Fluid Injector or Optical Fiber insertion at a time
- Interchangeable injector allows multiple session injections
- Stereotaxic Cannula Holder is available for implantation
Optical fiber Multiple Fluid Injection Cannula (OmFC)
- Ideal for single-site targeting, or dual-site with less than 1.4 mm inter-regional distance
- Configuration options: Both sides fluid injection, both sides optical fiber insertion, or one side fluid injection and the other optical fiber insertion.
- Interchangeable injector allows multiple session injections
- Stereotaxic Cannula Holder is available for implantation
Dual Optofluid Cannulas with Interchangeable Injectors (DFC)
- Ideal for dual-site targeting with larger than 1.4 mm inter-regional distance
- Configuration options: Both sides fluid injection, both sides optical fiber insertion, or one side fluid injection and the other optical fiber insertion.
- Interchangeable injector allows multiple session injections
- Stereotaxic Cannula Holder is available for implantation
Fluidic Miniscope Cannula
To integrate fluid injection with Doric miniscopes, only the Deep Brain Miniscope models are compatible with either the Snap-in Cannula or Twist-on Cannula.
These specialized cannulas are designed to accommodate both a GRIN lens and injection tubing, allowing imaging and fluid delivery in the same brain region.
* Note that currently, we do not offer a solution supporting imaging and fluid injection in two separate brain areas.
Twist-on Imaging Cannula with Fluid Injection
- Ideal for single site targeting
- compatible with doric Efocus 1-color deep brain miniscope
- Uses interchangeable injector for multiple injections
- Stereotaxic Cannula Holder is available for implantation
Snap-in Imaging Cannula with Fluid Injection
- Ideal for single site targeting
- compatible with doric Snap-in 1 color and 2-color (model L) deep brain miniscopes
- Stereotaxic Cannula Holder is available for implantation
- Uses interchangeable injector for multiple injections
Opto-Fluidic Rotary Joint
When performing simultaneous fluid injection and optogenetics/photometry in freely moving mice, it’s important to prevent tubing and cables from tangling and restricting movement. In such cases, a compatible opto-fluidic rotary joint is recommended to support natural animal behavior.
Fiber-optic & Liquid Rotary Joint
- Ideal for Fluid Injection alone or fluid injection and optogenetics stimulation
- NOT compatible with fiber photometry
Rotary Fluorescence Mini Cube (RFMC)
- Ideal for simultaneous fluid Injection and Fiber Photometry recording in freely-moving animals
Fluidic Injectors for Opto-Fluidic Cannulas
All Doric opto-fluidic cannulas require a fluidic injector for fluid delivery. The injector is connected to the tubing system and then inserted into the cannula to deliver the solution. After each use, the injector can be removed, rinsed, and stored for future use.
This approach offers several advantages:
- Easy cleaning and clog prevention: The injector can be rinsed after each use, helping prevent clogging caused by tissue or fluid debris. This allows the injector to be reused reliably for subsequent fluid delivery.
- Reduced dead space: Because the injector is connected directly to the end of the tubing, it can be filled with the desired solution before insertion into the cannula. This minimizes dead space in the system and helps ensure consistent and reliable fluid delivery, particularly at low injection rates.
Users can select the injector material and connector type according to their experimental requirements. The connector is generally available in two configurations: M3 thread or sleeve connector.
The table below summarizes the available injector materials and their respective advantages and disadvantages.
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test |
46mm or 42mm |
49mm |
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Up to 18 hours |
Up to 18 hours |
Up to 36 hours |
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S8 SiP |
S10 SiP |
S9 SiP |
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Up to 1,000 nits |
Up to 2,000 nits |
Up to 3,000 nits |
Limitations and Technical Challenges:
While opto-fluid cannulas offer powerful experimental capabilities, several limitations and best practices should be considered about fluid injection. Here we highlight a few:
- Fluidic Injector Size: Larger core injectors can cause mechanical damage and gliosis around the implantation site, potentially affecting neural activity and experimental outcomes. Using thinner, low-profile injectors help minimize these effects but may reduce fluid transmission efficiency.
- Optimal Fluid Delivery Rates: Injection rates that are too fast can cause backflow or tissue disruption, while very slow rates may be ineffective. A commonly recommended infusion rate is between 50–200 nL/min, depending on the viscosity of the solution and the target brain region.
- Long Tubing Considerations: Long and flexible tubing can introduce dead volume and delay between the start of injection and fluid delivery, which complicates time-sensitive protocols. Pre-filling tubing and validating flow rate are essential steps in reducing variability.
- Clogging of Injectors: Injectors may clog over time due to particulates in solutions or dried residues. To prevent clogging, researchers should filter all solutions, flush injectors after use with distilled water or appropriate solvents, and avoid prolonged storage with fluid in the lines.
Accessories
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References:
- 2025, eLife — Cold induces brain region-selective cell activity-dependent lipid metabolism. Used Optical Fiber Multiple Fluid Injections (OmFC) Cannulas positioned over PVH.
- 2025, Nature Communications — Brainstem noradrenergic modulation of the kisspeptin neuron GnRH pulse generator in mice.
- 2022, Pharmacological Research — Photopharmacological manipulation of amygdala metabotropic glutamate receptor mGlu4 alleviates neuropathic pain. Used Optical Fiber Multiple Fluid Injections (OmFC) Cannula in Amygdala.
- 2018, eLife — Manipulating midbrain dopamine neurons and reward-related behaviors with light-controllable nicotinic acetylcholine receptors. Used Optofluid Cannula with interchangeable injectors (iOFC) in the VTA.
- 2023, Cell reports - Mechanism of kisspeptin neuron synchronization for pulsatile hormone secretion in male mice. Used Optical Fiber Multiple Fluid Injections (OmFC) Cannulas positioned above the mid-caudal arcuate nucleus kisspeptin.
- 2021, Communications Biology - AAV1 is the optimal viral vector for optogenetic experiments in pigeons (Columba livia). Used dual fiberoptic cannula (DFC) for bilateral fluid injections.