We have successfully achieved the integration of isothermal amplification and the subsequent analysis of specific gene fragments on poly(methyl methacrylate) microchips. In our experiments, loop-mediated isothermal amplification, which can offer higher specificity and efficiency than PCR, has been performed at a constant temperature (65°C ). After amplification, products could be either examined by the integrated microchip-based electrophoresis or directly observed by naked eye with SYBR Green I added into the reaction solution. By such an integrated microsystem, the amplification and the subsequent analysis of prostate-specific antigen gene with template concentration at 23 fg/µL could be finished within 15 min, which demonstrates its advantages of high specificity, good reproducibility, and fast speed in gene detection.Sequencing of the human genome has been almost completed, and the human genome project quickly moves on to the postgenome-sequencing era. [1][2][3][4] During this period, further development of analytical technology is highly required for high-throughput screening of disease-causing genes and high-speed analysis of genetic polymorphism on an individual genome. Accordingly, the development of novel microchip-based methods for ultrafast DNA analysis has been challenged, especially for the amplification and analysis of genetic locus on the genome. [5][6][7][8] Since its initial study from the middle of 1980s, PCR has been playing an important role in modern biology research. 9 During the amplification, thermal cycling with temperature ranging from 50 to 100°C is indispensable. Therefore, most reported PCR chips are fabricated by either glass or silicon. 10-13 However, polymer microchips, which are expected to be very promising in the future, 14 can hardly endure the high temperature during PCR. Accordingly, amplification at a relatively low temperature should be especially developed for them.Up until now, several isothermal amplification methods under mild conditions have been proposed, including nucleic acid sequence-based amplification, 15 self-sustained sequence replication, 16 and strand displacement amplification. 17,18 Each of them has its own innovation to reinitiate new rounds of DNA synthesis, but there are still drawbacks to overcome. 19,20 They require either a precision instrument for amplification or an elaborate method for detecting the amplified products due to poor specificity of target sequence selection. Loop-mediated isothermal amplification (LAMP) is another newly invented method that can amplify a few copies of DNA to 10 9 within 1 h under isothermal condi-* To whom correspondence should be addressed. Phone: +86-411-83693459.

PCR is an indispensable technique used in DNA analysis. However, with the traditional methods, the time spent on amplification and the subsequent analysis of PCR products is generally long. Therefore, it is essential to improve these two steps so that the whole procedure can be made faster. In the present work, with λ-DNA as the control template, the amplification of 300-bp fragment could be completed within 37 s with capillary reaction chambers of LightCycler, and the following analysis of PCR products could be completed within 120 s with microchip electrophoresis as the detector. Since the high detection sensitivity of microchip electrophoresis, PCR products with template concentration as low as 5 fg/µL could be detected only after 435 s of amplification. In addition, based on additional optimized conditions simulated by CoventorWare, PCR microchips with distinct structure of the reaction chambers have been designed and successfully applied to the amplification of 300-bp fragment. By comparison, those chambers with ellipse and racket shapes were found to offer very high amplification efficiency. All of these results demonstrate the promise of integrating PCR and electrophoresis on microchip for developing easy-carrying instruments for the fast in situ detection of DNA.