We present a self-powered integrated microfluidic blood analysis system (SIMBAS) that does not require any external connections, tethers, or tubing to deliver and analyze a raw whole-blood sample. SIMBAS only requires the user to place a 5 μL droplet of whole-blood at the inlet port of the device, whereupon the stand-alone SIMBAS performs on-chip removal of red and white cells, without external valving or pumping mechanisms, followed by analyte detection in platelet-containing plasma. Five complete biotin-streptavidin sample-to-answer assays are performed in 10 min; the limit of detection is 1.5 pM. Red and white blood cells are removed by trapping them in an integral trench structure. Simulations and experimental data show 99.9% to 100% blood cell retention in the passive structure. Powered by pre-evacuation of its PDMS substrate, SIMBAS' guiding design principle is the integration of the minimal number of components without sacrificing effectiveness in performing rapid complete bioassays, a critical step towards point-of-care molecular diagnostics.

Highly selective and sensitive optical methods for the detection of metal ions have had a substantial impact on molecular biology, environmental monitoring and other areas of research. Here we demonstrate a new method for detecting metal ions that is based on selective plasmonic resonance energy transfer (PRET) between conjugated metal-ligand complexes and a single gold nanoplasmonic probe. In addition to offering high spatial resolution due to the small size of the probe, our method is 100 to 1,000 times more sensitive than organic reporter-based methods. Moreover, it can achieve high selectivity owing to the selective formation of Cu(2+) complexes and selective resonant quenching of the gold nanoplasmonic probe by the conjugated complexes. We expect that PRET-based metal ion sensing could have applications in cellular imaging, systems biology and environmental monitoring.

A noble metal ion (Pt 2+ and Pd 2+ ) adsorbent with uniform mesopore channels was prepared by grafting a thiol functional group, (3-mercaptopropyl)trimethoxysilane (MPTMS), onto ordered mesoporous silica, SBA-15. Results show that the ordered mesostructure of SBA-15 was retained after modification and the thiol functional group was immobilized mainly inside the mesopore channel, as evidenced by Brunauer-Emmett-Teller surface area, small-angle X-ray scattering, Fourier transform infrared, and elemental analyses. The thiolated mesoporous silica exhibited a highly selectively adsorptive capability for noble metal ions such as Pd 2+ and Pt 2+ , while the binding capability for other metal ions (Ni 2+ , Cu 2+ , and Cd 2+ ) both in the presence of equimolarity and at 10 times excess conditions was greatly decreased. These selective adsorptions of thiolated mesoporous adsorbent for noble metal ions (Pt 2+ and Pd 2+ ) were explained by thermodynamic calculation assuming that the selective adsorption occurred by a chemical adsorption on the surface of a confined pore channel. In addition, the adsorption characteristics of the thiolated mesoporous material were examined.

Reliable, autonomous, internally self-powered microfluidic pumps are in critical demand for rapid point-of-care (POC) devices, integrated molecular-diagnostic platforms, and drug delivery systems. Here we report on a Self-powered Imbibing Microfluidic Pump by Liquid Encapsulation (SIMPLE), which is disposable, autonomous, easy to use and fabricate, robust, and cost efficient, as a solution for self-powered microfluidic POC devices. The imbibition pump introduces the working liquid which is sucked into a porous material (paper) upon activation. The suction of the working liquid creates a reduced pressure in the analytical channel and induces the sequential sample flow into the microfluidic circuits. It requires no external power or control and can be simply activated by a fingertip press. The flow rate can be programmed by defining the shape of utilized porous material: by using three different paper shapes with circular section angles 20°, 40° and 60°, three different volume flow rates of 0.07 μL s(-1), 0.12 μL s(-1) and 0.17 μL s(-1) are demonstrated at 200 μm × 600 μm channel cross-section. We established the SIMPLE pumping of 17 μL of sample; however, the sample volume can be increased to several hundreds of μL. To demonstrate the design, fabrication, and characterization of SIMPLE, we used a simple, robust and cheap foil-laminating fabrication technique. The SIMPLE can be integrated into hydrophilic or hydrophobic materials-based microfluidic POC devices. Since it is also applicable to large-scale manufacturing processes, we anticipate that a new chapter of a cost effective, disposable, autonomous POC diagnostic chip is addressed with this technical innovation.