Glass microfluidic chips

Jia, Z-J., Q. Fang, and Z-L. Fang. Bonding of glass microfluidic chips at room temperatures. Anal. Chem. 16, 5597-5602 (2004). 

FIGURE 2.3 Sequence for fabrication of the glass microfluidic chip, (a) Cr and Au masked glass plate coated with photoresist (b) sample exposed to UV light through a photomask (c) photoresist developed (d) exposed metal mask etched (e) exposed glass etched (f) resist and metal stripped (g) glass cover plate bonded to form sealed capillary [102]. Reprinted with permission from American Chemical Society. 

The interference-filters and CdS-filters described above could in principle be straightforwardly integrated with glass microfluidic chips, but they are unsuitable for conformable elastomeric materials such as PDMS - a preferred substrate material for low-cost disposable applications - since polycrystalline materials such as CdS, Ti02, and Si02 are t3T3ically deposited at relatively high temperatures (>300°C) and have a tendency to crack when the substrate is flexed. 

Glass microfluidic chips with inserted nano-ESI emitters, electroosmotic pumping capillaries, or capillary transfer lines inserted in the liquid sheath interface of a Q-TOF instrument, were also used for the CE analysis of standard peptide/protein digests and of gel-isolated proteins from complex cellular extracts (H. influenza, P. Some of these chips enabled sam-... 

Laser-induced Raman microscopy can be used to monitor a chemical reaction in a microfluidic channel. In situ monitoring of imine formation reaction in a glass microfluidic chip was previously performed. In order to moni-... 

Lee M, Lee JP, Rhee H, Choo J, Chai YG, Lee EK (2003) Applicability of Laser-Induced Raman Microscopy for In-Situ Monitoring of Imine Formation in a Glass Microfluidic Chip. J Raman Spectrosc 34 737-742... 

The sequence includes several synthetic steps over polymer-supported catalysts in directly coupled commercially available Omnifit glass reaction columns [41] using a Syrris Africa microreactor system [14], Thales H-Cube flow hydrogenator [32] and a microfluidic chip. The process affords the alkaloid in 90% purity after solvent evaporation, but in a moderate 40% yield. After a closer investigation it was concluded that this is due to the poor yield of 50% in the phenolic oxidation step. On condition that this is resolved with the use of a more effective supported agent, the route would provide satisfactory yields and purities of the product. 

FIGURE D.3 CaUper s microfluidics chip fabricated in glass. 

Zhou et al. [175] described the determination of severe acute respiratory syndrome (SARS) coronavirus by a microfluidic chip system. The unit included an LIF microfluidic chip analyzer, a glass microchip for both PCR and capillary electrophoresis, a chip thermal cycler based on dual Peltier thermoelectric elements, a reverse transcription-polymerase chain reaction (RT-PCR) SARS diagnostic kit, and a DNA electrophoretic sizing kit. According to the authors, the system allowed efficient DNA amplification of the SARS coronavirus followed by electrophoretic sizing and detection on the same chip. 

Huang et al. [176] described an integrated microfluidic chip (of PDMS and soda-lime glass) capable of performing DNA/RNA amplification, electroki-netic sample injection and separation, and online optical detection in an automatic mode. The authors tested its functionality for bacterial DNA of Streptococcus pneumoniae and RNA of dengue-2 vims. The NCE developed represented a crucial contribution to the fields of molecular biology, genetic analysis, infectious disease detection, and other biomedical applications. 

In order to provide liquid access to the microfluidic chips, holes are usually created on the cover plate. These access holes are usually created on glass by drilling using diamond drill bits. However, other methods have also been used, and these are summarized in Table 2.4. 

In conclusion, the advantages of microfluidic devices, parallel synthesis, and combinatorial approaches can be merged to integrate a fluorescent chemical sensor array in a microfluidic chip. Fluorescent microchannel array can be produced by parallel synthesis of fluorescent monolayers covalent attached to the walls of glass microchannels. 

Easley et al. showed integrated DNA purification, PCR, electrophoretic separation and detection of pathogens in less than 30 min [116]. The assay was performed on a pressure driven four layer glass/PDMS chip with elastomeric valves. Temperature cycling for PCR was achieved by IR radiation. Only the sample lysis step was not integrated in the microfluidic chip. Detection of Bacillus anthracis from infected mice and Bordetella pertussis from a clinical sample was successfully demonstrated. 

Figure 7.8 High-throughput configuration chips. (A) Drawing of a 3 in x 3 in glass substrate containing six fully integrated LC systems. (Reprinted with permission from ref. 33.) (B) Microfluidic chip (3 in x 1 in) comprising two fully integrated LC systems. (Reprinted with permission from ref. 35).

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