Technical Performance

VaHeat enables swift changes in sample temperature, reaching rates of up to 100 °C/s for heating and -20 °C/s for cooling. This allows for precise, real-time studies of temperature sensitive processes.

• Transparent heating element
• Calibrated temperature probe (R25, TKR parameters)
• Top surface is glass only and can be functionalized
• Multi-use disposable (typical 5–10 uses per substrate)
• Utra-low fluorescence glass suited for SR microscopy

• For liquid samples
• Made from biocompatible silicone for live cell studies

Our system’s local heating and feedback mechanism allow for precise and rapid temperature control within the field of view. For small thermal loads, such as thin films, heating rates can reach up to 100 °C per second. When working with larger thermal loads, such as liquid samples, heating rates of up to 40 °C per second are achievable (see Figure 1). In scenarios with minimal or no thermal load, the system can deliver a heat response of up to 100 °C (see Figure 2). For applications requiring faster heating of larger thermal loads, our extended range version provides enhanced performance.

To demonstrate that VaHeat enables diffraction-limited studies at temperatures above 50°C, even when using high numerical aperture (NA) immersion objectives, we experimentally determined the three-dimensional point spread function (PSF) of sub-diffraction-limited beads across various sample temperatures. At temperatures above 80°C, we observed a slight increase in the PSF in the x-y plane, attributed to enhanced particle diffusion. Additionally, an elongation of the focal point in the z-direction was noted, caused by spherical aberration due to changes in the refractive index of the immersion oil at elevated temperatures. This effect is highly dependent on the properties of the immersion medium and can be mitigated by accounting for the effective change in optical path length. Notably, imaging quality remains unaffected when using air-spaced objectives.

The precise temperature probe embedded within our smart substrates, coupled with a fast response time, enables effective compensation for both slow and rapid external temperature fluctuations, such as those caused by air flow or fluid exchange. This ensures precise long-term temperature stabilization, maintaining accuracy within 0.01 °C (RMS) over extended periods, ranging from hours to days. Additionally, local temperature management is essential for maintaining high mechanical stability and preventing any drifts.

VaHeat sets a new standard for temperature precision in optical microscopy. The system not only monitors the temperature directly at the sample volume but also compensates for external disturbances or incorrect system settings. For example, it can adjust for an incorrectly calibrated incubator or an objective at an incorrect temperature when brought into contact with the sample.