An all-at-once factorial method is presented, which optimizes protein ink deposition using microfabricated pens by identifying the pen design which writes the greatest number of uniform-size spots or droplets without re-inking. Pen features associated with capillary ink transport are varied according to statistical design-of-experiment (SDOE) principles, and evaluated using a special 1D pen array of twelve pens. Variable parameter pens are bracketed by control pens. Each pen array element embodies one component of the SDOE matrix. All parameters are evaluated simultaneously with a single droplet writing pass. Results can also be evaluated simultaneously, leading to rapid choice of those pen parameters which deliver the greatest number of printed features having the smallest coefficient of variation.
The conventional approach to measurement of the deflection of microfabricated cantilevers centers on the use of an optical lever. The use of optical lever technology increases the size, complexity, and cost of systems using microfabricated cantilevers. Occasionally, piezoresistors have been used to sense deflection. But, for atomic force microscope applications in particular, topographical sensitivity has demanded the higher sensitivity of the optical lever. For dip-pen nanolithography (DPN) microfabricated cantilevers do not require the same degree of deflection sensitivity. So, for these applications, piezoresistors can be used to sense deflection. In this work, we present a novel approach to an integrated DPN pen. Piezoresistive silicon stress sensors are integrated into a silicon nitride cantilever. The device design, process design, and fabrication methods for building these sensors, and sensor-actuators, are demonstrated. Integration of heaters, along with the piezoresistors, is also demonstrated.
Precision nanoscale deposition is a fundamental requirement for nanoscience research, development, and commercial
implementation. Dip Pen Nanolithography(R) (DPN) is an inherently additive SPM-based technique which operates
under ambient conditions, making it suitable to deposit a wide range of biological and inorganic materials. This
technique is fundamentally enabled by a portfolio of MEMS devices tailored for microfluidic ink delivery, directed
placement of nanoscale materials via actuated cantilevers, and cm2 tip arrays for high-throughput nanofabrication.
Multiplexed deposition of nanoscale materials is a challenging problem, but we have implemented InkWells(TM) to enable
selective delivery of ink materials to different tips in multiple probe arrays, while preventing cross-contamination.
Active Pens(TM) can take advantage of this, directly place a variety of materials in nanoscale proximity, and do so in a
"clean" fashion since the cantilevers can be manipulated in Z. Further, massively parallel two-dimensional
nanopatterning with DPN is now commercially available via NanoInk's 2D nano PrintArray(TM), making DPN a highthroughput,
flexible and versatile method for precision nanoscale pattern formation. By fabricating 55,000 tip-cantilevers
across a 1 cm2 chip, we leverage the inherent versatility of DPN and demonstrate large area surface coverage, routinely
achieving throughputs of 3×107 μm2 per hour. Further, we have engineered the device to be easy to use, wire-free, and
fully integrated with the NSCRIPTOR's scanner, stage, and sophisticated lithography routines. In this talk we discuss the
methods of operating this commercially available device, and subsequent results showing sub-100 nm feature sizes and
excellent uniformity (standard deviation < 16%). Finally, we will discuss applications enabled by this MEMS portfolio
including: 1) rapidly and flexibly generating nanostructures; 2) chemically directed assembly and 3) directly writing
Dip Pen Nanolithography® (DPN®) is an inherently additive SPM-based technique which operates under ambient
conditions, making it suitable to deposit a wide range of biological and inorganic materials. Massively parallel two-dimensional
nanopatterning with DPN is now commercially available via NanoInk's 2D nano PrintArrayTM, making
DPN a high-throughput, flexible and versatile method for precision nanoscale pattern formation. By fabricating 55,000
tip-cantilevers across a 1 cm2 chip, we leverage the inherent versatility of DPN and demonstrate large area surface
coverage, routinely achieving throughputs of 3x107 μm2 per hour. Further, we have engineered the device to be easy to
use, wire-free, and fully integrated with the NSCRIPTOR's scanner, stage, and sophisticated lithography routines. In this
talk we discuss the methods of operating this commercially available device, subsequent results showing sub-100 nm
feature sizes and excellent uniformity (standard deviation < 16%), and our continuing development work. Simultaneous
multiplexed deposition of a variety of molecules is a fundamental goal of massively parallel 2D nanopatterning, and we
will discuss our progress on this front, including ink delivery methods, tip coating, and patterning techniques to generate
combinatorial libraries of nanoscale patterns. Another fundamental challenge includes planar leveling of the
2D nano PrintArray, and herein we describe our successful implementation of device viewports and integrated software
leveling routines that monitor cantilever deflection to achieve planarity and uniform surface contact. Finally, we will
discuss the results of 2D nanopatterning applications such as: 1) rapidly and flexibly generating nanostructures; 2)
chemically directed assembly and 3) directly writing biological materials.
Precision nanoscale deposition is a fundamental requirement for much of current nanoscience research. Further,
depositing a wide range of materials as nanoscale features onto diverse surfaces is a challenging requirement for
nanoscale processing systems. As a high resolution scanning probe-based direct-write technology, Dip Pen
Nanolithography® (DPN®) satisfies and exceeds these fundamental requirements. Herein we specifically describe the
massive scalability of DPN with two dimensional probe arrays (the 2D nano PrintArray). In collaboration with
researchers at Northwestern University, we have demonstrated massively parallel nanoscale deposition with this 2D
array of 55,000 pens on a centimeter square probe chip. (To date, this is the highest cantilever density ever reported.)
This enables direct-writing flexible patterns with a variety of molecules, simultaneously generating 55,000 duplicates at
the resolution of single-pen DPN. To date, there is no other way to accomplish this kind of patterning at this
unprecedented resolution. These advances in high-throughput, flexible nanopatterning point to several compelling
applications. The 2D nano PrintArray can cover a square centimeter with nanoscale features and pattern 107 &mgr;m2 per
hour. These features can be solid state nanostructures, metals, or using established templating techniques, these advances
enable screening for biological interactions at the level of a few molecules, or even single molecules; this in turn can
enable engineering the cell-substrate interface at sub-cellular resolution.
Dip Pen Nanolithography (DPNTM) is a scanning probe technique for nanoscale lithography: A sharp tip is coated with a functional molecule (the “ink”) and then brought into contact with a surface where it deposits ink via a water meniscus. The DPN process is a direct-write pattern transfer technique with nanometer resolution and is inherently general with respect to usable inks and substrates including biomolecules such as proteins and oligonucleotides. We present functional extensions of the basic DPN process by showing actuated multi-probes as well as microfluidic ink delivery. We present the fabrication process and characterization of such active probes that use the bimorph effect to induce deflection of individual cantilevers as well as the integration of these probes. We also developed the capability to write with multiple inks on the probe array permitting the fabrication of multi-component nanodevices in one writing session. For this purpose, we fabricate passive microfluidic devices and present microfluidic behavior and ink loading performance of these components.