A Review of Heating and Temperature Control in Microfluidic Systems: Techniques and Applications

Abstract

This review presents an overview of the different techniques developed over the last decade to regulate the temperature within microfluidic systems. A variety of different approaches has been adopted, from external heating sources to Joule heating, microwaves or the use of lasers to cite just a few examples. The scope of the technical solutions developed to date is impressive and encompasses for instance temperature ramp rates ranging from 0.1 to 2,000 °C/s leading to homogeneous temperatures from −3 °C to 120 °C, and constant gradients from 6 to 40 °C/mm with a fair degree of accuracy. We also examine some recent strategies developed for applications such as digital microfluidics, where integration of a heating source to generate a temperature gradient offers control of a key parameter, without necessarily requiring great accuracy. Conversely, Temperature Gradient Focusing requires high accuracy in order to control both the concentration and separation of charged species. In addition, the Polymerase Chain Reaction requires both accuracy (homogeneous temperature) and integration to carry out demanding heating cycles. The spectrum of applications requiring temperature regulation is growing rapidly with increasingly important implications for the physical, chemical and biotechnological sectors, depending on the relevant heating technique.

Microscale Transport Phenomena for Bio-Engineering Applications: Recent Advances

“…The paper discussed MEMS based temperature measurement techniques, and bio-medical and bio-analytical devices and techniques. Miralles et al (2013) has presented a review of the techniques and applications of heating and temperature control in microfluidic systems. Recent strategies where integration of a heating source to generate a temperature gradient, thus offering control of a key parameter, as well as methods where high accuracy temperature gradient focusing is utilized, are examined in this paper.…”

A novel on-chip three-dimensional micromachined calorimeter with fully enclosed and suspended thin-film chamber for thermal characterization of liquid samples

“…Resistive heating (Joule heating) is selected as a heat source in this work to achieve homogeneous heating with a wide operational temperature range, better heat control compared to other methods 30 and for ease of integration onto thin film substrates. 31 An integrated resistive temperature detector (RTD) is used for the temperature sensor in this work.…”

Integrated System Based on Thin Film Technologies for Cell-Based Bioluminescence Assays

“…Several solutions have been proposed including the use of photosensors based on organic or inorganic materials [5,6]. On the other hand, in order to avoid bulky, heavy heating blocks [7], different microheaters have been developed [8,9] to ensure a uniform temperature profile.…”