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Abstract A microfluidic SERS chip integrated with blood separation and in-situ detection was designed and fabricated for the rapid detection of clinical blood samples. Each functional unit in the microfluidic SERS chip consist of separation-decantation cavity based on centrifugal separation principle, mixing channels and SERS detection chamber built with integrated nano-Au on Ag film microstructure. The serum creatinine was selected as a typical sample to demonstrate the capability of microfluidic SERS chip. It was found that the creatinine SERS characteristic peaks at 678 cm−1 can be effectively identified and the detection limit could be as low as 4.42 × 10−3 μmol mL−1 in water. The blood samples were also tested in microfluidic SERS chip. The whole separation and test process could be completed within 2 min, which is a significant improvement in the field of creatinine detection. The whole blood of six cases clinical blood samples were also tested, and the results were consistent with the enzymatic results. The developed microfluidic SERS chip has advantages including reduction of the required quantity of blood sample, reusable and easy to operate. It is expected to provide a new method for rapid diagnostics. Graphical abstract fx1 Highlights • Nano-Au on Ag film taken as SERS substrate was prepared in-situ in the detecting chamber for detection. • The serum separated by microchannels was directly injected into the chamber on the designed chip for SERS detection. • The integrated microfluidic SERS chip was applied to detect rapidly the clinical serum creatinine within 2 min. [ABSTRACT FROM AUTHOR]

Abstract: To set up a point-of-care whole-blood immunoassay system, sample preparation and on-chip storage of conjugate reagents are indispensable functional units. Here, we merge these functions into a deposited microbead plug (DMBP) to simultaneously play the roles of a blood filter and a conjugate reagent carrier. The DMBP was easily fabricated by the use of natural deposition of beads without the need of weirs. Conjugate reagents (FITC labeled antibodies used here) were incorporated into the DMBP during the assembly of the DMBP. To demonstrate the ability of the DMBP, we constructed a DMBP-based microfluidic chip and used it for the detection of human IgG (hIgG). The DMBP enabled to remove blood cells from whole blood and provide the pure plasma for the downstream on-chip immunoreactions. The release of reconstituted FITC labeled antibodies from the DMBP was controlled in a passive fashion. Dry FITC labeled antibodies retained at least 81% of their activity after 60 days of storage at the room temperature. The DMBP presented here makes an important step towards the development of the self-contained, integrated, sample-to-answer microfluidic chips for point-of-care diagnostics. [Copyright &y& Elsevier]