Magnetic Janus Particles for Static and Dynamic (Bio)Sensing

Abstract

Magnetic Janus particles bring together the ability of Janus particles to perform two different functions at the same time in a single particle with magnetic properties enabling their remote manipulation, which allows headed movement and orientation. This article reviews the preparation procedures and applications in the (bio)sensing field of static and self-propelled magnetic Janus particles. The main progress in the fabrication procedures and the applicability of these particles are critically discussed, also giving some clues on challenges to be dealt with and future prospects. The promising characteristics of magnetic Janus particles in the (bio)sensing field, providing increased kinetics and sensitivity and decreased times of analysis derived from the use of external magnetic fields in their manipulation, allows foreseeing their great and exciting potential in the medical and environmental remediation fields.

From Single-Core Nanoparticles in Ferrofluids to Multi-Core Magnetic Nanocomposites: Assembly Strategies, Structure, and Magnetic Behavior

“…More precisely, when the solution temperature exceeded the glass transition temperature (T g ), a high degree of nanoparticle fusion occurred, giving uniform nanofibers, while at solution temperatures below the Tg, necklace-like morphologies were obtained due to partial nanoparticle fusion (Figure 10). By employing the same fabrication strategy starting from polystyrene-capped colloidal magnetite nanoparticles exhibiting a Janus morphology [181], anisotropic zig-zag nanomorphologies were generated in the presence of a magnetic field.…”

“…nanofibers, while at solution temperatures below the Tg, necklace-like morphologies were obtained due to partial nanoparticle fusion (Figure 10). By employing the same fabrication strategy starting from polystyrene-capped colloidal magnetite nanoparticles exhibiting a Janus morphology [181], anisotropic zig-zag nanomorphologies were generated in the presence of a magnetic field. Increasing the temperature above the glass transition temperature (Tg) provides enough polymer chain flexibility and leads to a linear sintering process.…”

Magnetic Nanoparticles

“…Magnetic Janus nanoparticles bring together the ability of Janus particles to perform two different functions at the same time in a single particle with magnetic properties enabling their remote manipulation, which allows headed movement and orientation. The article by Campuzano et al [17] reviews the preparation procedures and applications in the (bio)sensing field of static and self-propelled magnetic Janus nanoparticles. The main progress in the fabrication procedures and the applicability of these nanoparticles are critically discussed, also giving some clues on challenges to be dealt with and future prospects.…”

Biosensing and Delivery of Nucleic Acids Involving Selected Well-Known and Rising Star Functional Nanomaterials

“…Unlike conventional nanoparticles, two-faced Janus nanodevices, which can be prepared with different morphologies and shapes (Figure 1a) [40], provide anisotropy in structure, constitution, and surface chemistry. These characteristics allow their use to perform complementary functions, achieving outcomes not feasible in the biosensing and cargo delivery areas using conventional nanoparticles [40,41,42,43,44]. Furthermore, analytical functions such as targeting or sensing are spatially decoupled by the surface anisotropy of Janus particles; this allows selective bioconjugation in the spatial environment and provides improved functions and properties such as dual targeting and biosensing [45], not achievable when other single structured or heterogeneous non-Janus nanoparticles are used.…”

“…These synthetic methods can be classified as (a) masking or template, (b) direct deposition, (c) phase separation, and (d) self-assembly. Moreover, Janus nanoparticles may incorporate a magnetic material to allow magnetic driving [43,44]. Regarding biosensing, these unique nanoparticles have been exploited as transducer modifiers [47,48] and advanced nanocarriers of signaling molecules for signal amplification [49,50].…”