Thermoplastic nanofluidic devices for identifying abasic sites in single DNA molecules

Abstract

DNA damage can take many forms such as double-strand breaks and/or the formation of abasic (apurinic/apyrimidinic; AP) sites. The presence of AP sites can be used to determine therapeutic efficacy...

High Sensitivity Extended Nano-Coulter Counter for Detection of Viral Particles and Extracellular Vesicles

“…In the optimized design we positioned the in-plane pores next to a 4 μm 3D tapered funnel to further increase the sampling efficiency by extending the electric field into the sampling microchannel. 25 An SEM image of the funnel and the XnCC can be seen in Figure 1C(iv).…”

“…We preliminarily evaluated three different XnCC designs with one consisting of a single in-plane pore and two with 5 parallel in-plane pores (see Figures S2, S3, and S4). XnCC design iterations, COMSOL simulations, and experimental results (see the Supporting Information) provided insights into the design configuration required to improve the sampling efficiency to lower the concentration limit-of-detection: (i) utilize multiple pores in parallel; (ii) reduce the width of the sampling microchannel near the pores and place the pores close to the sampling microchannel; (iii) high pressure drop across the pores; (iv) utilize a 3D tapered funnel to extend the electric field further into the sampling microchannel to electrophoretically draw particles into the in-plane pores; and (v) utilize an optimized forward hydraulic flow. The design iterations shown in the Supporting Information led us to the optimized design, as discussed below.…”

“…The width of the access microchannels was 25 μm (width and depth), but in the region near the 5 pores (i.e., sampling microchannel), the channel was reduced to 10 μm (Figure B­(ii)) to increase the sampling efficiency, defined as the number of particles per unit time traveling through the in-plane pores (Figure A) with respect to the total number of particles traveling through the sampling microchannel. In the optimized design we positioned the in-plane pores next to a 4 μm 3D tapered funnel to further increase the sampling efficiency by extending the electric field into the sampling microchannel . An SEM image of the funnel and the XnCC can be seen in Figure C­(iv).…”

Fluidic operation of a polymer-based nanosensor chip for analysing single molecules

“…The time evolution of particle movement (figure 4 e ) was: (i) t = 0 s, where the particles were in the pillar array; (ii) t = 2.9 s, where the first particle was seen inside the nano-tube; (iii) t = 6 s, where more particles were seen entering into the nano-tube; and (iv) t = 7.3 s in which most particles travelled through the nano-tube. The inlet of the nano-tubes had a funnel shaped entrance (see figure 2 c showing the entrance of the nano-tube) tapering in width and depth leading to the nano-tube so that there was a larger capture area for products released from the pillar arrays (Vaidyanathan et al., 2021). The field strength profile (figure 4 b ) also showed that the area surrounding the funnel entrance had a small radius with a higher field strength.…”

Nano-injection molding with resin mold inserts for prototyping of nanofluidic devices for single molecular detection

“…Our group previously reported the use of resin molds for thermal nanoimprint lithography of thermoplastics, which offers many advantages including low demolding force associated with a low Young's modulus of the cured UV-resin and reduced thermal expansion coefficient mismatch between the substrate and mold insert, ease of producing molds with positive or negative tones by repetitive replication processes, and extended lifetime of expensive Si master molds. 54,[56][57][58] The overall process schematics are shown in Fig. S1, † which broadly consisted of fabricating Si master molds via a combination of photolithography and Si etching for microfluidic networks with FIB milling for generating nanostructures, replication of Si master molds to produce resin mold inserts, and injection molding of thermoplastics with the resin mold inserts.…”