The importance of microfluidics for the preparation of nanoparticles as advanced drug delivery systems

ABSTRACT

Introduction: Nanoparticles are anticipated to overcome persistent challenges in efficient drug delivery, but the limitations associated with conventional methods of preparation are resulting in slow translation from research to clinical applications. Due to their enormous potential, microfluidic technologies have emerged as an advanced approach for the development of drug delivery systems with well-defined physicochemical characteristics and in a reproducible manner.

Areas covered: This review provides an overview of microfluidic devices and materials used for their manufacturing, together with the flow patterns and regimes commonly used for nanoparticle preparation. Additionally, the different geometries used in droplet microfluidics are reviewed, with particular attention to the co-flow geometry used for the production of nanoparticles. Finally, this review summarizes the main and most recent nanoparticulate systems prepared using microfluidics, including drug nanosuspensions, polymeric, lipid, structured, and theranostic nanoparticles.

Expert opinion: The production of nanoparticles at industrial scale is still a challenge, but the microfluidic technologies bring exciting opportunities to develop drug delivery systems that can be engineered in an easy, cost-effective and reproducible manner. As a highly interdisciplinary research field, more efforts and general acceptance are needed to allow for the translation of nanoparticulate drug delivery systems from academic research to the clinical practice.

KEYWORDS:

• Drug delivery systems
• nanoparticles
• microfluidics
• co-flow geometry
• nanoprecipitation

Article highlights

• Microfluidic technologies allow for the development of drug delivery systems with well-defined physicochemical characteristics and in a reproducible manner.

• For the production nanoparticulate systems, microfluidics techniques rely mostly on nanoprecipitation processes in microscale fluidic channels with continuous flows.

• Microfluidic devices for particle production are mainly divided into microchannels and microcapillaries.

• Exploratory research in microfluidic devices has been mostly carried out in polydimethylsiloxane (PDMS), silica or glass, however, fused silica, hydrogel molds, polytetrafluoroethylene, polystyrene, poly(methyl methacrylate) have also been used.

• The droplets formed in microfluidic devices are affected by the velocities of the solvents used, their viscosities and densities, surface tension and chemistry, and the geometry of the device.

• The use of microfluidics is paving the way for the successful preparation of drug nanosuspensions, polymeric, lipid, structured, and theranostic nanoparticles.

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Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

H.A. Santos acknowledges financial support from the Academy of Finland (decision no. 304844), the University of Helsinki Research Funds, the HiLIFE Research Funds, Sigrid Jusélius Foundation (decision no. 4704580) and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013, grant no. 310892).