Single-cell droplet microfluidics for biomedical applications.

Single-cell manipulation and analysis is critical to the study of many fundamental biological processes and uncovering cellular heterogeneity, and presents the potential for extremely valuable applications in biomedical fields, including neuroscience, regenerative therapy, early diagnosis, and drug screening. The use of microfluidic technologies in single-cell manipulation and analysis is one of the most promising approaches and enables the creation of innovative conditions that are impractical or impossible to achieve using conventional methods. Herein, an overview of the technological development of single-cell droplet microfluidics is presented. The significant advantages of microfluidic droplet technology, the dynamic parameters affecting droplet production, and the geometric structures of microfluidic devices are emphasized. Furthermore, the progress to date in passive and active droplet generation methods based on microfluidics and various microfluidic tools for the production of single-cell droplets and hydrogel microspheres are summarized. Their key features, achievements, and limitations associated with single-cell droplet and hydrogel formation are discussed. The recent popularized applications of single-cell droplet microfluidics in biomedicine involving small-molecule detection, protein analysis, and drug screening and genetic analysis of single cells are explored too. Finally, the challenges that must be overcome to enable future applications in single-cell droplet microfluidics are highlighted.

Advances in Micro/Nanoporous Membranes for Biomedical Engineering.

Porous membrane materials at the micro/nanoscale have exhibited practical and potential value for extensive biological and medical applications associated with filtration and isolation, cell separation and sorting, micro-arrangement, in-vitro tissue reconstruction, high-throughput manipulation and analysis, and real-time sensing. Herein, an overview of technological development of micro/nanoporous membranes (M/N-PMs) is provided. Various membrane types and the progress documented in membrane fabrication techniques, including the electrochemical-etching, laser-based technology, microcontact printing, electron beam lithography, imprinting, capillary force lithography, spin coating, and microfluidic molding are described. Their key features, achievements, and limitations associated with micro/nanoporous membrane (M/N-PM) preparation are discussed. The recently popularized applications of M/N-PMs in biomedical engineering involving the separation of cells and biomolecules, bioparticle operations, biomimicking, micropatterning, bioassay, and biosensing are explored too. Finally, the challenges that need to be overcome for M/N-PM fabrication and future applications are highlighted.

Superparamagnetic microsphere-assisted fluoroimmunoassay for rapid assessment of acute myocardial infarction.

Rapid assessment of acute myocardial infarction (AMI) was successfully demonstrated using an improved superparamagnetic polymer microsphere-assisted sandwich fluoroimmunoassay to detect two early cardiac markers-myoglobin and human heart-type fatty acid binding protein (H-FABP). This assay used a preparation of superparamagnetic poly(styrene-divinylbenzene-acrylamide) microspheres, glutaraldehyde-coupled capture antibodies (monoclonal anti-myoglobin 7C3 and anti-H-FABP 10E1) grafted onto the polymer microspheres, and a sequential sandwich fluoroimmunoassay using detection antibodies (FITC-labeled anti-myoglobin 4E2 and FITC-labeled anti-H-FABP 9F3). Characterization of the polymer microspheres by TEM, SEM and Fourier transform infrared spectroscopy (FT-IR) showed that the microspheres were uniformly round with an average diameter of 1.12 microm, and had a Fe(3)O(4)-polymer core-shell structure (shell thickness was about 84 nm) with 0.22 mmol/g amino groups on their surfaces. The magnetic behavior of the Fe(3)O(4)-polymer microspheres was superparamagnetic (M(s)=13 emu/g, H(c)=13.1 Oe). Fluorescence images of the post-immunoassay microspheres recorded using a confocal laser-scanning microscope showed that the average fluorescence intensity was correlated with the concentration of cardiac markers, in agreement with the results obtained by an F-4500 FL spectrophotometer; this indicated that the fluoroimmunoassay could be used to semi-quantitatively detect both myoglobin and H-FABP. The detection limit was 25 ng/mL for myoglobin and 1 ng/mL for H-FABP.