CoolLED pE-300opto LED light source for advanced optogenetic applications

The pE-300^opto from CoolLED is a high-performance LED illumination platform developed specifically for optogenetics in neuroscience. The system is engineered to deliver temporally precise, high-irradiance stimulation across both ex vivo and in vivo preparations, while maintaining compatibility with a broad range of opsins and standard fluorescence imaging workflows.

The pE-300^opto incorporates three high-power LEDs — blue (470 nm), green-yellow (550 nm) and red (635 nm). Each channel can be optimised with inline excitation filters to match commonly used opsins. The blue and green wavelengths are designed to efficiently drive established tools such as Channelrhodopsin-2 and Halorhodopsin, while the red channel is designed to enable activation of red-shifted variants including ChrimsonR and Jaws. This spectral configuration is engineered to support deeper tissue penetration as well as multi-opsin experimental designs requiring clean spectral separation. As the field continues to adopt red-shifted and spectrally diverse opsins, the system is positioned to accommodate emerging tools without requiring hardware replacement.

High-speed, multi-channel control is central to the architecture of the platform. Each LED can be independently triggered with <10 µs TTL precision, enabling accurate temporal alignment with electrophysiology, behavioural paradigms or high-speed imaging systems. Irradiance is adjustable in 1% increments across the full 0–100% range, allowing fine control of stimulation intensity when calibrating across multiple opsins or experimental conditions. Inline excitation filter holders remove the need for moving optical components, improving mechanical stability and maintaining spectral consistency during rapid triggering protocols.

To streamline complex stimulation paradigms, the integrated Sequence Runner functionality allows users to define LED combinations and irradiance levels via the manual control interface and then execute these sequences automatically. Synchronisation is achieved through a global TTL input and a single TTL output from a camera, designed to facilitate high-speed, multi-opsin stimulation without additional external control hardware.

A liquid light guide output is provided as standard, making the system well suited to ex vivo optogenetics under a microscope and to fluorescence imaging applications spanning fluorophores such as GFP, YFP, mCherry and Cy5. For in vivo experiments, an optional adaptor is designed to enable fibre output via SMA or FC connectors, and the output is designed to be readily swapped between configurations. This flexibility is designed to allow researchers to deploy a single light source across multiple experimental environments, from fibre-based stimulation in behaving animals to slice electrophysiology and combined stimulation–imaging experiments.