Over
the past decades, nanoparticles have increased in implementation
to a variety of applications ranging from high-efficiency electronics
to targeted drug delivery. Recently, microfluidic techniques have
become an important tool to isolate and enrich populations of nanoparticles
with uniform properties (
e.g.
, size,
shape, charge) due to their precision, versatility, and scalability.
However, due to the large number of microfluidic techniques available,
it can be challenging to identify the most suitable approach for isolating
or enriching a nanoparticle of interest. In this review article, we
survey microfluidic methods for nanoparticle isolation and enrichment
based on their underlying mechanisms, including acoustofluidics, dielectrophoresis,
filtration, deterministic lateral displacement, inertial microfluidics,
optofluidics, electrophoresis, and affinity-based methods. We discuss
the principles, applications, advantages, and limitations of each
method. We also provide comparisons with bulk methods, perspectives
for future developments and commercialization, and next-generation
applications in chemistry, biology, and medicine.