title: 3D porous sol-gel matrix incorporated microdevice for effective large volume cell sample pretreatment.
abstract: In this study, we demonstrated an effective sample pretreatment microdevice that could perform the capture, purification, and release of pathogenic bacteria with a large-volume sample and at a high speed and high-capture yield. We integrated a sol-gel matrix into the microdevice which forms three-dimensional (3D) micropores for the cell solution to pass through and provides a large surface area for the immobilization of antibodies to capture the target Staphylococcus aureus (S. aureus) cells. The antibody was linked to the surface of the sol-gel via a photocleavable linker, allowing the cell-captured antibody moiety to be released by UV irradiation. In addition to the optimization of the antibody immobilization and UV cleavage processes, the cell-capture efficiency was maximized by controlling the sample flow rate with a pumping scheme (3 steps, 5 steps: 3 steps with one flutter step, 7 steps: 3 steps with two flutter steps) and the pumping time (100, 200, and 300 ms). A quantitative capture analysis was performed by targeting a specific gene site of protein A of S. aureus in real-time PCR (RT-PCR). While the 3-step process with an actuation time of 100 ms showed the fastest flow rate (1 mL sample processing time in 10 min), the pumping scheme with the 7-step process and the 300 ms actuation time revealed the highest cell-capture efficiency. A limit of detection study with the 7-step and the 300 ms pumping scheme demonstrated that 100 cells per 100 μL were detected with a 70% yield, and even a single cell could be analyzed via on-chip sample preparation. Thus, our novel sol-gel based microdevice was proven more cost-effective, simple, and efficient in terms of its sample pretreatment ability compared to the use of a conventional 2D flat microdevice. This proposed sample pretreatment device can be further incorporated to an analytical functional unit to realize a micrototal analysis system (μTAS) with sample-in-answer-out capability in the fields of biomedical diagnostics, food safety testing, and environmental pollutant screening.
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21 program), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Chan Joo
authors.initials: CJ
authors.lastname: Lee
authors.forename: Jae Hwan
authors.initials: JH
authors.lastname: Jung
authors.forename: Tae Seok
authors.initials: TS
authors.lastname: Seo
mesh_terms: D000906:Antibodies / Q000737:chemistry*; D005782:Gels; D055767:Immobilized Proteins / Q000737:chemistry*; D057230:Limit of Detection; D044367:Phase Transition; D055668:Photochemical Processes; D016062:Porosity; D060888:Real-Time Polymerase Chain Reaction; D013205:Staphylococcal Protein A / Q000032:analysis* / Q000737:chemistry; D013211:Staphylococcus aureus / Q000737:chemistry / Q000302:isolation & purification*; D014466:Ultraviolet Rays
chemical_list: D000906:Antibodies; D005782:Gels; D055767:Immobilized Proteins; D013205:Staphylococcal Protein A