Microfluidic technology provides opportunities to create in vitro models with physiological microenvironment for cell study.Introducing the identified key aspects,including tissue-tissue interfaces,spatiotemporal chemical gradients,and dynamic mechanical forces,of living organs into the microfluidic system,"organs-on-chips"display an unprecedented application potential in a lot of biological fields such as fundamental physiological and pathophysiological research,drug efficacy and toxicity testing,and clinical diagnosis.Here,we review the recent development of organs-on-chips and briefly discuss their future challenges.
This review begins with an overview of the appealing properties and various applications of gold nanoparticles, and briefly summarizes recent advances in using unmodified gold nanoparticles to detect different kinds of targets including nucleic acids, proteins, metal ions and small organic molecules. The key point to the unmodified gold nanoparticle-based visual detection assay is to control dispersion and aggregation of colloidal nanoparticles by targets of interest, which usually relies on affinities between gold nanoparticles and targets. The degree of dispersion or aggregation can be visualized through the change of the solution color or the precipitation of nanoparticles from the solution. Thus, the existence of the target molecules can be trans-lated into optical signals and monitored by the naked eye conveniently. Finally, some future prospects of this research field are given.
