It is critical to reliably and rapidly detect multiple disease biomarkers in tiny liquid samples with high sensitivity to meet the growing demand for point-of-care diagnostics. This paper reports a microfluidic platform integrating magnetic-based single bead trapping in conjunction with acoustic micromixing for simultaneous detection of multiple cancer biomarkers within minutes. Individual beads retained by permalloy (NiFe81/19) microarray were used to capture biomarkers and facilitate the fluorescence identification. A numerical study indicates that the magnetic force keeping a bead in the trap is proportional to the thickness of the permalloy array and the external magnetic field strength, while inversely proportional to the size of the trap. The acoustic microstreaming activated by a piezo transducer was applied to generate fast-switching flow patterns to minimize the diffusion length scales. The flow at various driving frequencies was experimentally tested to achieve the optimal mixing effect. The flow field of the microstreaming was subsequently described by a mathematical model to understand the flow further. Finally, the prostate-specific antigen (PSA) and carcinoembryonic antigen (CEA) were employed as model analytes to demonstrate the capability of the platform for rapid biomarker detection. With the aid of acoustic micromixing, the detection can be finished in 20 minutes. The respective limit of detection of PSA and CEA is 0.028 ng mL⁻¹ (0.8 pM) and 3.1 ng mL⁻¹ (17 pM), which is respectively 1/142 and 1/3 of the cutoff value of PSA and CEA. Our results indicate this platform has great potential for the rapid detection of multiple biomarkers in future point-of-care diagnostics.

Inoculation of single cells into separate chambers is one of the key requirements in single-cell analysis. Here we report a three-layer microfluidic platform integrated with dual-pneumatic valves for dynamic screening and printing of single cells.

Hard ticks feed on their host for multiple days. To ensure firm attachment, they secrete a protein-rich saliva that eventually forms a solid cement cone. The underlying mechanism of this liquid-to-solid transition is currently not understood. This study focuses on the phase transitions of a disordered glycine-rich protein (GRP) found in tick saliva. We show that GRP undergoes liquid–liquid phase separation via simple coacervation to form biomolecular condensates in salty environments. Cation–π and π–π interactions mediated by periodically placed arginine and aromatic amino-acid residues are the primary driving forces that promote phase separation. Interestingly, GRP condensates exhibit ageing by undergoing liquid-to-gel transition over time and exhibit adhesive properties, similar to the naturally occurring cement cone. Finally, we provide evidence for protein-rich condensates in natural tick saliva. Our findings provide a starting point to gain further insights into the bioadhesion of ticks, to develop novel tick control strategies, and towards achieving biomedical applications such as tissue sealants.