Temperature is a critical—yet sometimes overlooked—parameter in microfluidics. Microfluidic devices can experience heating inside their channels during operation due to underlying physicochemical phenomena occurring therein. Such heating, whether required or not, must be monitored to ensure adequate device operation. Therefore, different techniques have been developed to measure and control temperature in microfluidic devices. In this contribution, the operating principles and applications of these techniques are reviewed. Temperature-monitoring instruments revised herein include thermocouples, thermistors, and custom-built temperature sensors. Of these, thermocouples exhibit the widest operating range; thermistors feature the highest accuracy; and custom-built temperature sensors demonstrate the best transduction. On the other hand, temperature control methods can be classified as external- or integrated-methods. Within the external methods, microheaters are shown to be the most adequate when working with biological samples, whereas Peltier elements are most useful in applications that require the development of temperature gradients. In contrast, integrated methods are based on chemical and physical properties, structural arrangements, which are characterized by their low fabrication cost and a wide range of applications. The potential integration of these platforms with the Internet of Things technology is discussed as a potential new trend in the field.

中文翻译：

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微流控器件温度监测和控制的最新进展和挑战

温度是微流体中一个关键但有时被忽视的参数。由于其中发生的潜在物理化学现象，微流体装置在操作过程中会在其通道内经历加热。无论是否需要，都必须监控此类加热以确保设备正常运行。因此，已经开发了不同的技术来测量和控制微流体装置中的温度。在本文中，回顾了这些技术的操作原理和应用。此处修订的温度监测仪器包括热电偶、热敏电阻和定制温度传感器。其中，热电偶表现出最宽的工作范围；热敏电阻具有最高的精度；和定制的温度传感器展示了最好的转换。另一方面，温度控制方法可分为外部方法或集成方法。在外部方法中，微加热器被证明在处理生物样品时最合适，而珀耳帖元件在需要形成温度梯度的应用中最有用。相比之下，集成方法基于化学和物理特性、结构排列，其特点是制造成本低、应用范围广。这些平台与物联网技术的潜在集成被讨论为该领域的潜在新趋势。而珀耳帖元件在需要形成温度梯度的应用中最为有用。相比之下，集成方法基于化学和物理特性、结构排列，其特点是制造成本低、应用范围广。这些平台与物联网技术的潜在集成被讨论为该领域的潜在新趋势。而珀耳帖元件在需要形成温度梯度的应用中最为有用。相比之下，集成方法基于化学和物理特性、结构排列，其特点是制造成本低、应用范围广。这些平台与物联网技术的潜在集成被讨论为该领域的潜在新趋势。