This paper presents the fabrication of low-resistance carbon MEMS/NEMS as material for biosensing... more This paper presents the fabrication of low-resistance carbon MEMS/NEMS as material for biosensing. The carbon source is the negative photoresist SU8 epoxy. At room temperature the SU8 is in liquid form, making it easier to mix with nanoparticles. The SU8 epoxy is mixed with single-walled-Carbon-Nanotubes (swCNTs) and stirred for 48 h. The experimental variable was the weight percentage (wt%) of swCNTs in the SU8 epoxy. The controlled variables were the layer thickness and experimental environment such as the room’s humidity and furnace model. The silicon wafer was used as substrate because it can withstand high temperatures during the pyrolysis step. The spin coater was used for coating the mixture onto the substrates uniformly. The spinning process was repeated for sample design 2 and 3 to obtain the double layer characteristic. Samples were exposed to ultra-violet (UV) radiation for 40 s. This process is called photolithography. The samples were heated on the hotplate before (pre-...
Nanowire sensors offer great potential as highly sensitive electrochemical and electronic biosens... more Nanowire sensors offer great potential as highly sensitive electrochemical and electronic biosensors because of their small size, high aspect ratios, and electronic properties. Nevertheless, the available methods to fabricate carbon nanowires in a controlled manner remain limited to expensive techniques. This paper presents a simple fabrication technique for sub-100 nm suspended carbon nanowire sensors by integrating electrospinning and photolithography techniques. Carbon Microelectromechanical Systems (C-MEMS) fabrication techniques allow fabrication of high aspect ratio carbon structures by patterning photoresist polymers into desired shapes and subsequent carbonization of resultant structures by pyrolysis. In our sensor platform, suspended nanowires were deposited by electrospinning while photolithography was used to fabricate support structures. We have achieved suspended carbon nanowires with sub-100 nm diameters in this study. The sensor platform was then integrated with a mic...
Reversible thermo-pneumatic valves (RTPVs) manipulate thermal energy to reversibly block or open ... more Reversible thermo-pneumatic valves (RTPVs) manipulate thermal energy to reversibly block or open microchannels. The valves prevent the evaporation of reagents during thermocycling periods. The cartridge is used for sequential aliquoting to prepare multiple PCR reaction mixtures for the detection of the Dengue virus.
A centrifugal compact disc (CD) microfluidic platform with reservoirs, micro-channels, and valves... more A centrifugal compact disc (CD) microfluidic platform with reservoirs, micro-channels, and valves can be employed for implementing a complete immunoassay. Detection or biosensor chambers are either coated for immuno-interaction or a biosensor chip is inserted in them. On microfluidic CDs featuring such multi-step chemical/biological processes, the biosensor chamber must be repeatedly filled with fluids such as enzymes solutions, buffers, and washing solutions. After each filling step, the biosensor chamber needs to be evacuated by a passive siphoning process to prepare it for the next step in the assay. However, rotational speed dependency and limited space on a CD are two big obstacles to performing such repetitive filling and siphoning steps. In this work, a unique thermo-pneumatic (TP) Push-Pull pumping method is employed to provide a superior alternative biosensor chamber filling and evacuation technique. The proposed technique is demonstrated on two CD designs. The first design...
This paper presents the fabrication of low-resistance carbon MEMS/NEMS as material for biosensing... more This paper presents the fabrication of low-resistance carbon MEMS/NEMS as material for biosensing. The carbon source is the negative photoresist SU8 epoxy. At room temperature the SU8 is in liquid form, making it easier to mix with nanoparticles. The SU8 epoxy is mixed with single-walled-Carbon-Nanotubes (swCNTs) and stirred for 48 h. The experimental variable was the weight percentage (wt%) of swCNTs in the SU8 epoxy. The controlled variables were the layer thickness and experimental environment such as the room’s humidity and furnace model. The silicon wafer was used as substrate because it can withstand high temperatures during the pyrolysis step. The spin coater was used for coating the mixture onto the substrates uniformly. The spinning process was repeated for sample design 2 and 3 to obtain the double layer characteristic. Samples were exposed to ultra-violet (UV) radiation for 40 s. This process is called photolithography. The samples were heated on the hotplate before (pre-...
Nanowire sensors offer great potential as highly sensitive electrochemical and electronic biosens... more Nanowire sensors offer great potential as highly sensitive electrochemical and electronic biosensors because of their small size, high aspect ratios, and electronic properties. Nevertheless, the available methods to fabricate carbon nanowires in a controlled manner remain limited to expensive techniques. This paper presents a simple fabrication technique for sub-100 nm suspended carbon nanowire sensors by integrating electrospinning and photolithography techniques. Carbon Microelectromechanical Systems (C-MEMS) fabrication techniques allow fabrication of high aspect ratio carbon structures by patterning photoresist polymers into desired shapes and subsequent carbonization of resultant structures by pyrolysis. In our sensor platform, suspended nanowires were deposited by electrospinning while photolithography was used to fabricate support structures. We have achieved suspended carbon nanowires with sub-100 nm diameters in this study. The sensor platform was then integrated with a mic...
Reversible thermo-pneumatic valves (RTPVs) manipulate thermal energy to reversibly block or open ... more Reversible thermo-pneumatic valves (RTPVs) manipulate thermal energy to reversibly block or open microchannels. The valves prevent the evaporation of reagents during thermocycling periods. The cartridge is used for sequential aliquoting to prepare multiple PCR reaction mixtures for the detection of the Dengue virus.
A centrifugal compact disc (CD) microfluidic platform with reservoirs, micro-channels, and valves... more A centrifugal compact disc (CD) microfluidic platform with reservoirs, micro-channels, and valves can be employed for implementing a complete immunoassay. Detection or biosensor chambers are either coated for immuno-interaction or a biosensor chip is inserted in them. On microfluidic CDs featuring such multi-step chemical/biological processes, the biosensor chamber must be repeatedly filled with fluids such as enzymes solutions, buffers, and washing solutions. After each filling step, the biosensor chamber needs to be evacuated by a passive siphoning process to prepare it for the next step in the assay. However, rotational speed dependency and limited space on a CD are two big obstacles to performing such repetitive filling and siphoning steps. In this work, a unique thermo-pneumatic (TP) Push-Pull pumping method is employed to provide a superior alternative biosensor chamber filling and evacuation technique. The proposed technique is demonstrated on two CD designs. The first design...
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Papers by Fatimah Ibrahim