Microfluidic Synthesis of Iron Oxide Nanoparticles.

Zachary Stephen,Miqin Zhang,Richard A Revia,Matthew James

doi:10.3390/nano10112113

Abstract

Research efforts into the production and application of iron oxide nanoparticles (IONPs) in recent decades have shown IONPs to be promising for a range of biomedical applications. Many synthesis techniques have been developed to produce high-quality IONPs that are safe for in vivo environments while also being able to perform useful biological functions. Among them, coprecipitation is the most commonly used method but has several limitations such as polydisperse IONPs, long synthesis times, and batch-to-batch variations. Recent efforts at addressing these limitations have led to the development of microfluidic devices that can make IONPs of much-improved quality. Here, we review recent advances in the development of microfluidic devices for the synthesis of IONPs by coprecipitation. We discuss the main architectures used in microfluidic device design and highlight the most prominent manufacturing methods and materials used to construct these microfluidic devices. Finally, we discuss the benefits that microfluidics can offer to the coprecipitation synthesis process including the ability to better control various synthesis parameters and produce IONPs with high production rates.

Highlights

iron oxide nanoparticles (IONPs) have gained much attention due to their versatile applications in nanomedicine as diagnostic and therapeutic agents in the fight against human disease
This review aims to provide a current overview of the microfluidic coprecipitation of IONPs
We review the most commonly used manufacturing methods and materials for the creation of microfluidic devices for IONP production; we include a discussion of the important design choices in device manufacturing methods and material selection

Summary

Introduction

IONPs have gained much attention due to their versatile applications in nanomedicine as diagnostic and therapeutic agents in the fight against human disease. Due to the lack of control over mixing and other parameters, traditional coprecipitation techniques may yield IONPs with a broad size distribution, and batch-to-batch inconsistency in IONP size, crystallinity, morphology, and other physicochemical properties [29] To overcome these drawbacks and produce high-quality IONPs in large quantity, a recent effort has been made on developing microfluidic devices to make IONPs. A microfluidic device is made of any series of interconnected micron-scale channels etched into or formed from a variety of materials. As a result of this laminar flow, the nucleation and growth of IONPs is generally diffusion controlled in microfluidic devices [31] These small-scale channels provide large surface area-to-volume ratios, which enhances the homogeneity of the solution and in turn increases the heat and mass transport in the solution [33]. We discuss the unique benefits that the microfluidic devices can bring about such as the ability to better control key synthesis parameters for improved properties of IONPs and to enable large-scale production

Microfluidic Architectures for Coprecipitation of IONPs

Drop‐Wise Flow Reactors

Drop-Wise Flow Reactors

Gas-Segmented Flow Reactors

Fabrication of Microfluidic Devices for Production of IONPs

Materials Used in the Creation of IONP-Producing Microfluidic Devices

Polymers

Experimental Design Parameters and Their Control over IONP Synthesis

The Effect of Coprecipitation Synthesis Parameters

The Effect of Channel Dimensions on Synthesis of IONPs

Scale-Up Synthesis of IONPs

Conclusions and Outlook