Dielectrophoretic Capture of Cancer-Derived Small-Extracellular-Vesicle-Bound Janus Nanoparticles via Lectin-Glycan Interaction.

Glycosylation is closely related to cellular metabolism and disease progression. In particular, glycan levels in cancer cells and tissues increase during cancer progression. This upregulation of glycosylation in cancer cells may provide a basis for the development of new biomarkers for the targeting and diagnosis of specific cancers. Here, they developed a detection technology for pancreatic cancer cell-derived small extracellular vesicles (PC-sEVs) based on lectin-glycan interactions. Lectins specific for sialic acids are conjugated to Janus nanoparticles to induce interactions with PC-sEVs in a dielectrophoretic (DEP) system. PC-sEVs are selectively bound to the lectin-conjugated Janus nanoparticles (lectin-JNPs) with an affinity comparable to that of conventionally used carbohydrate antigen 19-9 (CA19-9) antibodies. Furthermore, sEVs-bound Lectin-JNPs (sEVs-Lec-JNPs) are manipulated between two electrodes to which an AC signal is applied for DEP capture. In addition, the proposed DEP system can be used to trap the sEVs-Lec-JNP on the electrodes. Their results, which are confirmed by lectin-JNPs using the proposed DEP system followed by target gene analysis, provide a basis for the development of a new early diagnostic marker based on the glycan characteristics of PC-sEVs. In turn, these novel detection methods could overcome the shortcomings of commercially available pancreatic cancer detection techniques.

The Dielectrophoretic Alignment of Biphasic Metal Fillers for Thermal Interface Materials.

Pad-type thermal interface materials (TIMs) with composite structures are required to exhibit high thermal conductivity while maintaining conformal contact with the heat sink, which is strongly influenced by the type and content of the thermally conductive filler. This study presents that biphasic metal particles can be effectively aligned using the dielectrophoretic chaining (DEP-C) mechanism, thereby enhancing the thermal conductivity of a pad-type TIM. A eutectic gallium-indium (EGaIn) alloy liquid metal and solid copper were used as the filler materials with two different phases. The biphasic metal particle mixture of EGaIn and Cu (EGaIn-Cu) were better aligned by DEP-C than when they presented individually because fusion between the two particles increased the effective size. As expected, the thermal conductivity of the TIM composites increased when DEP-C aligned the filler. Notably, TIMs with both EGaIn-Cu fillers showed the largest increase in thermal conductivity, of up to 64.6%, and the highest thermal conductivity values after DEP-C application compared to TIMs with only the EGaIn or Cu filler. Finally, the heat dissipation performance of the TIM composite on a lit light-emitting diode is shown, where the TIM with DEP-C-aligned fillers exhibits improved performance.

Dielectrophoretic Manipulation of Janus Particle in Conductive Media for Biomedical Applications.

Janus particles are applied to many fields including biomedical applications. To expand the usability of Janus particles, a technique to manipulate the particle movement is required. A dielectrophoresis (DEP) method can be a promising candidate; however, independent manipulation or separation of Janus particle by DEP is still challenging. Additionally, DEP of Janus particles in conductive media is important especially for biomedical applications where ion-rich media are typically used. Here, the experimental results of DEP-induced transport and separation of the Janus particle in conductive media are presented. To predict the DEP behavior, the Clausius-Mossotti (CM) factors of both Janus and homogeneous particles are calculated, depending on the alternating current (AC) frequency and medium conductivity. The Janus particles show the positive-DEP behavior at the entire AC frequency region tested due to the metal-coated half surface. On the other hand, the homogeneous particles show the negative-DEP behavior at the high AC frequency or in conductive media. Additionally, in the conductive media, an electrohydrodynamic flow hinders the DEP-driven particle transport below MHz AC frequencies. Finally, the separation of the Janus particles from the homogeneous ones is experimentally demonstrated and the separation efficiency is discussed based on the evaluation parameters established in this study.