Proximal Probes Based Nanorobotic Drawing of Polymer Micro/Nanofibers

Nain, Amrinder S.; Amón, Cristina H.; Sitti, Metin

doi:10.1109/tnano.2006.880453

Cited by 49 publications

(23 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fibers were spun at room temperature and relative humidity of 15%. After fiber deposition, samples were cured at 40 C for 1 h. Structural stiffness (N/m) of individual polystyrene fibers was determined using a Bioscope II atomic force microscope (Veeco, Plainview, NY) in contact mode at several points along the length of the fiber (43,44). We used tipless cantilevers (AppNano, Mountain View, CA) with stiffness values ranging from 0.02 to 0.57 N/m calibrated using thermal tuning before measurements.…”

Section: Step Fiber Deposition and Structural Stiffness Characterizationmentioning

confidence: 99%

Role of Suspended Fiber Structural Stiffness and Curvature on Single-Cell Migration, Nucleus Shape, and Focal-Adhesion-Cluster Length

Meehan

Nain

2014

Biophysical Journal

View full text Add to dashboard Cite

It has been shown that cellular migration, persistence, and associated cytoskeletal arrangement are highly dependent on substrate stiffness (modulus: N/m(2) and independent of geometry), but little is known on how cells respond to subtle changes in local geometry and structural stiffness (N/m). Here, using fibers of varying diameter (400, 700, and 1200 nm) and length (1 and 2 mm) deposited over hollow substrates, we demonstrate that single mouse C2C12 cells attached to single suspended fibers form spindle morphologies that are sensitive to fiber mechanical properties. Over a wide range of increasing structural stiffness (2 to 100+ mN/m), cells exhibited decreases in migration speed and average nucleus shape index of ∼57% (from 58 to 25 μm/h) and ∼26% (from 0.78 to 0.58), respectively, whereas the average paxillin focal-adhesion-cluster (FAC, formed at poles) length increased by ∼38% (from 8 to 11 μm). Furthermore, the increase in structural stiffness directly correlates with cellular persistence, with 60% of cells moving in the direction of increasing structural stiffness. At similar average structural stiffness (25 ± 5 mN/m), cells put out longer FAC lengths on smaller diameters, suggesting a conservation of FAC area, and also exhibited higher nucleus shape index and migration speeds on larger-diameter fibers. Interestingly, cells were observed to deform fibers locally or globally through forces applied through the FAC sites and cells undergoing mitosis were found to be attached to the FAC sites by single filamentous tethers. These varied reactions have implications in developmental and disease biology models as they describe a strong dependence of cellular behavior on the cell's immediate mechanistic environment arising from alignment and geometry of fibers.

show abstract

Section: Step Fiber Deposition and Structural Stiffness Characterizationmentioning

confidence: 99%

Role of Suspended Fiber Structural Stiffness and Curvature on Single-Cell Migration, Nucleus Shape, and Focal-Adhesion-Cluster Length

Meehan

Nain

2014

Biophysical Journal

View full text Add to dashboard Cite

show abstract

“…Probe-based drawing can fabricate polymer nanowires. [ 17 ] However, high-density integration is limited by the large pre-deposited polymer droplet (a few tens to hundreds of micrometers).An alternate technique for 3D electrodeposition was recently developed: writing nanowires with a nanoscale electrolyte meniscus. [ 18 , 19 ] This method was so far demonstrated for 3D metallic nanowires but not for conducting polymers.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Three‐Dimensional Writing of Conducting Polymer Nanowire Arrays by Meniscus‐Guided Polymerization

et al. 2011

View full text Add to dashboard Cite

Organic electronics increasingly impacts our everyday life with a variety of devices such as displays for TV or mobile appliances, smart cards and radio-frequency identifi cation (RFID) tags. [ 1 , 2 ] This blossoming domain could greatly profi t from effective ways to fabricate conducting or semiconducting organic nanowires. [ 3 ] Specifi cally, the three-dimensional (3D) and individual integration of each nanowire is essential [ 4 ] for many new device concepts, but so far this was not possible. Here we show the demonstration of accurate and versatile 3D direct writing of conducting polymer nanowires based on guiding a monomer meniscus by pulling a micropipette during oxidative polymerization. This is an important step for organic electronic integration with high density and enhanced freedom in circuit design.Conducting polymers such as polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) are very interesting materials because they combine tunable electrical transport characteristics and excellent mechanical properties. [ 5 ] In particular, conducting polymer nanowires are quite important for a broad range of nanodevices such as fi eld effect transistors, [ 3 ] bio-and chemical sensors, [ 6 , 7 ] and non-volatile memories. [ 8 ] Such nanowires are fabricated by soft lithography, [ 9 , 10 ] dip-pen lithography [ 11 ] and electrospinning. [ 12 ] However, these methods are still limited to in-plane patterning of low-aspect-ratio nanowires, whereas for advanced applications 3D patterning is essential.Direct ink writing and probe-based drawing are used for 3D wire patterning. The fi rst method, based on the extrusion of concentrated ink through a nozzle, was applied for 3D microfabrication with metals, oxides, and polymers. [13][14][15][16] However, bringing the wire diameter below micrometer-level is not easy due to the size and concentration of the ink particles. Probe-based drawing can fabricate polymer nanowires. [ 17 ] However, high-density integration is limited by the large pre-deposited polymer droplet (a few tens to hundreds of micrometers).An alternate technique for 3D electrodeposition was recently developed: writing nanowires with a nanoscale electrolyte meniscus. [ 18 , 19 ] This method was so far demonstrated for 3D metallic nanowires but not for conducting polymers.Here we show that this type of technique can in fact be used for conducting polymers offering high accuracy, excellent versatility and marked advantages with respect to alternate solutions. In essence, we obtained a stretched monomer meniscus by pulling a micropipette fi lled with a Py solution, exploiting oxidative polymerization in air. The wire radius so produced was accurately controlled down to ∼ 50 nm by tuning the pulling speed.The technique was successfully tested with specifi c focus on essential features for advanced organic nanodevice integration. Specifi cally, we produced dense arrays of different types of freestanding nanocomponents: straight wires, complex-shape wires, branche...

show abstract

“…The fibers were pulled using the approach outlined in [7]. Molecular weight of the PS solution was 2 × 10 6 gr/mol.…”

Section: Pdms Chip Preparationmentioning

confidence: 99%

Towards Hybrid Swimming Microrobots: Bacteria Assisted Propulsion of Polystyrene Beads

Behkam¹,

Sitti²

2006

2006 International Conference of the IEEE Engineering in Medicine and Biology Society

View full text Add to dashboard Cite

Compactness and efficiency of biomotors makes them superior to man-made actuators and a very attractive choice of actuation for micro/nanorobots. However, biomotors are difficult to work with due to complications associated with their isolation and reconstitution. To circumvent this problem, here we use flagellar motors inside the intact cell of S. marcescens bacteria. An array of bacteria is used as propeller for a 10 μm polystyrene (PS) bead. PS bead is tracked for several seconds and its displacements is compared with diffusion length of a 10 μm particle. It is shown that the bead moves with an average velocity of 17 μm/s. Orientation of adhesion of S. marcescens to polydimethylsiloxane (PDMS) chips and microscale PS fibers was also investigated. It is shown that for both substrates; only bacteria from farther behind the leading edge of the swarm, adhere in end-on configuration.

show abstract

Proximal Probes Based Nanorobotic Drawing of Polymer Micro/Nanofibers

Cited by 49 publications

References 34 publications

Role of Suspended Fiber Structural Stiffness and Curvature on Single-Cell Migration, Nucleus Shape, and Focal-Adhesion-Cluster Length

Role of Suspended Fiber Structural Stiffness and Curvature on Single-Cell Migration, Nucleus Shape, and Focal-Adhesion-Cluster Length

Three‐Dimensional Writing of Conducting Polymer Nanowire Arrays by Meniscus‐Guided Polymerization

Towards Hybrid Swimming Microrobots: Bacteria Assisted Propulsion of Polystyrene Beads

Contact Info

Product

Resources

About