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Abstract
We present a facile approach to sharpen dull carbon nanocone tip to make the materials more appropriate for AFM applications.
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Affiliation(s)
- Wei Huang
- State Key Laboratory of Materials Processing and Die & Mould Technology
- School of Materials Science and Engineering
- Huazhong University of Science and Technology (HUST)
- Wuhan 430074
- China
| | - Jianxun Xu
- Chinese Academy of Science Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety
- National Center for Nanoscience and Technology of China
- Beijing 100190
- China
| | - Xing Lu
- State Key Laboratory of Materials Processing and Die & Mould Technology
- School of Materials Science and Engineering
- Huazhong University of Science and Technology (HUST)
- Wuhan 430074
- China
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2
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Park S, Kang YJ, Majd S. A Review of Patterned Organic Bioelectronic Materials and their Biomedical Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:7583-7619. [PMID: 26397962 DOI: 10.1002/adma.201501809] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 05/17/2015] [Indexed: 06/05/2023]
Abstract
Organic electronic materials are rapidly emerging as superior replacements for a number of conventional electronic materials, such as metals and semiconductors. Conducting polymers, carbon nanotubes, graphenes, organic light-emitting diodes, and diamond films fabricated via chemical vapor deposition are the most popular organic bioelectronic materials that are currently under active research and development. Besides the capability to translate biological signals to electrical signals or vice versa, organic bioelectronic materials entail greater biocompatibility and biodegradability compared to conventional electronic materials, which makes them more suitable for biomedical applications. When patterned, these materials bring about numerous capabilities to perform various tasks in a more-sophisticated and high-throughput manner. Here, we provide an overview of the unique properties of organic bioelectronic materials, different strategies applied to pattern these materials, and finally their applications in the field of biomedical engineering, particularly biosensing, cell and tissue engineering, actuators, and drug delivery.
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Affiliation(s)
- SooHyun Park
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - You Jung Kang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Sheereen Majd
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
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Meinander K, Jensen TN, Simonsen SB, Helveg S, Lauritsen JV. Quantification of tip-broadening in non-contact atomic force microscopy with carbon nanotube tips. NANOTECHNOLOGY 2012; 23:405705. [PMID: 22995859 DOI: 10.1088/0957-4484/23/40/405705] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Carbon nanotube terminated atomic force microscopy (AFM) probes have been used for the imaging of 5 nm wide surface supported Pt nanoclusters by non-contact (dynamic mode) AFM in an ultra-high vacuum. The results are compared to AFM measurements done with conventional Si-tips, as well as with transmission electron microscopy images, which give accurate measures for cluster widths. Despite their ideal aspect ratio, tip-broadening is concluded to be a severe problem even when imaging with carbon nanotube tips, which overestimates the cluster width by several times the nominal width of the nanotube tip. This broadening is attributed to a bending of the carbon nanotubes, and not to pure geometrical factors, which coincidentally results in a significant improvement for relative height measurements of tightly spaced high aspect ratio structures, as compared to what can be achieved with geometrically limited conventional probes. Superior durability also stands out as a defining feature of carbon nanotube terminated probes, allowing them to give results with a greatly enhanced reproducibility.
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Affiliation(s)
- Kristoffer Meinander
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark
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Tran PA, Zhang L, Webster TJ. Carbon nanofibers and carbon nanotubes in regenerative medicine. Adv Drug Deliv Rev 2009; 61:1097-114. [PMID: 19647768 DOI: 10.1016/j.addr.2009.07.010] [Citation(s) in RCA: 339] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 07/16/2009] [Indexed: 12/22/2022]
Abstract
Carbon nanotubes and carbon nanofibers have long been investigated for applications in composite structural materials, semiconductor devices, and sensors. With the recent well-documented ability to chemically modify nanofibrous carbon materials to improve their solubility and biocompatibility properties: a whole new class of bioactive carbon nanostructures has been created for biological applications. This review focuses on the latest applications of carbon nanofibers and carbon nanotubes in regenerative medicine.
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Affiliation(s)
- Phong A Tran
- Physics Department, Brown University, Providence, RI 02912, USA
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Wilson NR, Macpherson JV. Carbon nanotube tips for atomic force microscopy. NATURE NANOTECHNOLOGY 2009; 4:483-491. [PMID: 19662008 DOI: 10.1038/nnano.2009.154] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The development of atomic force microscopy (AFM) over the past 20 years has had a major impact on materials science, surface science and various areas of biology, and it is now a routine imaging tool for the structural characterization of surfaces. The lateral resolution in AFM is governed by the shape of the tip and the geometry of the apex at the end of the tip. Conventional microfabrication routes result in pyramid-shaped tips, and the radius of curvature at the apex is typically less than 10 nm. As well as producing smaller tips, AFM researchers want to develop tips that last longer, provide faithful representations of complex surface topographies, and are mechanically non-invasive. Carbon nanotubes have demonstrated considerable potential as AFM tips but they are still not widely adopted. This review traces the history of carbon nanotube tips for AFM, the applications of these tips and research to improve their performance.
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Affiliation(s)
- Neil R Wilson
- Department of Physics, University of Warwick, Coventry, UK
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Yazdanpanah MM, Hosseini M, Pabba S, Berry SM, Dobrokhotov VV, Safir A, Keynton RS, Cohn RW. Micro-wilhelmy and related liquid property measurements using constant-diameter nanoneedle-tipped atomic force microscope probes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13753-13764. [PMID: 18986184 DOI: 10.1021/la802820u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The micro-Wilhelmy method is a well-established method of determining surface tension by measuring the force of withdrawing a tens of microns to millimeters in diameter cylindrical wire or fiber from a liquid. A comparison of insertion force to retraction force can also be used to determine the contact angle with the fiber. Given the limited availability of atomic force microscope (AFM) probes that have long constant diameter tips, force-distance (F-D) curves using probes with standard tapered tips have been difficult to relate to surface tension. In this report, constant diameter metal alloy nanowires (referred to as "nanoneedles") between 7.2 and 67 microm in length and 108 and 1006 nm in diameter were grown on AFM probes. F-D and Q damping AFM measurements of wetting and drag forces made with the probes were compared against standard macroscopic models of these forces on slender cylinders to estimate surface tension, contact angle, meniscus height, evaporation rate, and viscosity. The surface tensions for several low molecular weight liquids that were measured with these probes were between -4.2% and +8.3% of standard reported values. Also, the F-D curves show well-defined stair-step events on insertion and retraction from partial wetting liquids, compared to the continuously growing attractive force of standard tapered AFM probe tips. In the AFM used, the stair-step feature in F-D curves was repeatably monitored for at least 0.5 h (depending on the volatility of the liquid), and this feature was then used to evaluate evaporation rates (as low as 0.30 nm/s) through changes in the surface height of the liquid. A nanoneedle with a step change in diameter at a known distance from its end produced two steps in the F-D curve from which the meniscus height was determined. The step features enable meniscus height to be determined from distance between the steps, as an alternative to calculating the height corresponding to the AFM measured values of surface tension and contact angle. All but one of the eight measurements agreed to within 13%. The constant diameter of the nanoneedle also is used to relate viscous damping of the vibrating cantilever to a macroscopic model of Stokes drag on a long cylinder. Expected increases in drag force with insertion depth and viscosity are observed for several glycerol-water solutions. However, an additional damping term (associated with drag of the meniscus on the sidewalls of the nanoneedle) limits the sensitivity of the measurement of drag force for low-viscosity solutions, while low values of Q limit the sensitivity for high-viscosity solutions. Overall, reasonable correspondence is found between the macroscopic models and the measurements with the nanoneedle-tipped probes. Tighter environmental control of the AFM and treatments of needles to give them more ideal surfaces are expected to improve repeatability and make more evident subtle features that currently appear to be present on the F-D and Q damping curves.
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Affiliation(s)
- Mehdi M Yazdanpanah
- ElectroOptics Research Institute and Nanotechnology Center, University of Louisville, Louisville, Kentucky 40292, USA
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Vairavapandian D, Vichchulada P, Lay MD. Preparation and modification of carbon nanotubes: Review of recent advances and applications in catalysis and sensing. Anal Chim Acta 2008; 626:119-29. [DOI: 10.1016/j.aca.2008.07.052] [Citation(s) in RCA: 234] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 07/30/2008] [Accepted: 07/30/2008] [Indexed: 11/30/2022]
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Dobrokhotov VV, Yazdanpanah MM, Pabba S, Safir A, Cohn RW. Visual force sensing with flexible nanowire buckling springs. NANOTECHNOLOGY 2008; 19:035502. [PMID: 21817570 DOI: 10.1088/0957-4484/19/03/035502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A calibrated method of force sensing is demonstrated in which the buckled shape of a long flexible metallic nanowire, referred to as a 'nanoneedle', is interpreted to determine the applied force. An individual needle of 157 nm diameter by 15.6 µm length is grown on an atomic force microscope (AFM) cantilever with a desired orientation (by the method of Yazdanpanah et al 2005 J. Appl. Phys. 98 073510). Using a nanomanipulator the needle is buckled in the chamber of a scanning electron microscope (SEM) and the buckled shapes are recorded in SEM images. Force is determined as a function of deflection for an assumed elastic modulus by fitting the shapes using the generalized elastica model (De Bona and Zelenika 1997 Proc. Inst. Mech. Eng. C 211 509-17). In this calibration the elastic modulus (68.3 GPa) was determined using an auxiliary AFM measurement, with the needle in the same orientation as in the SEM. Following this calibration the needle was used as a sensor in a different orientation than the AFM coordinates to deflect a suspended PLLA polymer fiber from which the elastic modulus (2.96 GPa) was determined. The practical value of the sensing method does depend on the reliability and ruggedness of the needle. In this study the same needle remained rigidly secured to the AFM cantilever throughout the entire SEM/AFM calibration procedure and the characterization of the nanofiber.
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Affiliation(s)
- Vladimir V Dobrokhotov
- ElectroOptics Research Institute and Nanotechnology Center, University of Louisville, Louisville, KY 40292, USA
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Feng SC, Vorburger TV, Joung CB, Dixson RG, Fu J, Ma L. Computational models of a nano probe tip for static behaviors. SCANNING 2008; 30:47-55. [PMID: 18200506 DOI: 10.1002/sca.20079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
It is difficult to predict the measurement bias arising from the compliance of the atomic force microscope (AFM) probe. The issue becomes particularly important in this situation where nanometer uncertainties are sought for measurements with dimensional probes composed of flexible carbon nanotubes mounted on AFM cantilevers. We have developed a finite element model for simulating the mechanical behavior of AFM cantilevers with carbon nanotubes attached. Spring constants of both the nanotube and cantilever in two directions are calculated using the finite element method with known Young's moduli of both silicon and multiwall nanotube as input data. Compliance of the nanotube-attached AFM probe tip may be calculated from the set of spring constants. This paper presents static models that together provide a basis to estimate uncertainties in linewidth measurement using nanotubes. In particular, the interaction between a multiwall nanotube tip and a silicon sample is modeled using the Lennard-Jones theory. Snap-in and snap-out of the probe tip in a scanning mode are calculated by integrating the compliance of the probe and the sample-tip interacting force model. Cantilever and probe tip deflections and points of contact are derived for both horizontal scanning of a plateau and vertically scanning of a wall. The finite element method and the Lennard-Jones model provide a means to analyze the interaction of the probe and sample and measurement uncertainty, including actual deflection and the gap between the probe tip and the measured sample surface.
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Affiliation(s)
- Shaw C Feng
- Manufacturing Engineering Laboratory at the National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA.
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Solares SD, Matsuda Y, Goddard WA. Influence of the Carbon Nanotube Probe Tilt Angle on the Effective Probe Stiffness and Image Quality in Tapping-Mode Atomic Force Microscopy. J Phys Chem B 2005; 109:16658-64. [PMID: 16853119 DOI: 10.1021/jp052758g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previous studies have shown that when using carbon nanotubes (CNTs) as tapping-mode AFM probes, their tilt angle with respect to vertical (denoted phi) must be close to 0 degrees to obtain high-quality images and that very poor images are obtained for phi > 30 degrees . Here we present a quantitative theoretical investigation of the effect of phi on tapping-mode AFM imaging for single-wall and multiwall nanotube (SWNT and MWNT, respectively) probes of diameters 3.4-5.5 nm and aspect ratio 7.5, which have been found ideal for imaging via TEM. Using molecular and classical dynamics, we investigate the effect of phi on CNT probe stiffness (quantified through the maximum gradient of the tip-sample interaction force) and show that it decreases linearly with increasing phi, becoming negligible at around phi approximately 40 degrees , thus confirming the conclusions of previous studies. We find that MWNT probe stiffness is proportional to the number of walls, but that the difference in stiffness between SWNTs and MWNTs also decreases linearly with increasing phi and becomes negligible at around phi approximately 40 degrees . The simulated cross-sectional scans of a sample SWNT using two different values of phi show that the image can be distorted and shifted laterally when phi is large, in some cases giving measured heights appreciably greater than the sample dimensions. We show analytically that the tip-sample forces that occur during imaging can be significantly lower when CNT probes are used instead of conventional probes, even in the absence of buckling, and that they can be further reduced by increasing phi. On the basis of this result, we propose the design of free-standing kinked probes for the characterization of sensitive samples, whereby the probe approaches the sample at a vertical orientation and possesses a tilted section that regulates the tip-sample interaction forces.
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Affiliation(s)
- Santiago D Solares
- Materials and Process Simulation Center, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Solares SD, Esplandiu MJ, Goddard WA, Collier CP. Mechanisms of Single-Walled Carbon Nanotube Probe−Sample Multistability in Tapping Mode AFM Imaging. J Phys Chem B 2005; 109:11493-500. [PMID: 16852407 DOI: 10.1021/jp051363u] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
When using single-walled carbon nanotube (SWNT) probes to create AFM images of SWNT samples in tapping mode, elastic deformations of the probe and sample result in a decrease in the apparent width of the sample. Here we show that there are two major mechanisms for this effect, smooth gliding and snapping, and compare their dynamics to the case when a conventional silicon tip is used to image a bare silicon surface. Using atomistic and continuum simulations, we analyze in detail the shape of the tip-sample interaction potential for three model cases and show that in the absence of adhesion and friction forces, more than two discrete, physically meaningful solutions of the oscillation amplitude are possible when snapping occurs (in contrast to the existence of one attractive and one repulsive solution for conventional silicon AFM tips). We present experimental results indicating that a continuum of amplitude solutions is possible when using SWNT tips and explain this phenomenon with dynamic simulations that explicitly include tip-sample adhesion and friction forces. We also provide simulation results of SWNT tips imaging Si(111)-CH3 surface step edges and Au nanocrystals, which indicate that SWNT probe multistability may be a general phenomenon, not limited to SWNT samples.
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Affiliation(s)
- Santiago D Solares
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Lee SI, Howell SW, Raman A, Reifenberger R, Nguyen CV, Meyyappan M. Complex dynamics of carbon nanotube probe tips. Ultramicroscopy 2005; 103:95-102. [PMID: 15774270 DOI: 10.1016/j.ultramic.2004.09.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Revised: 08/11/2004] [Accepted: 09/11/2004] [Indexed: 11/22/2022]
Abstract
Carbon nanotube (CNT) tips in tapping mode atomic force microscopy (AFM) enable very high-resolution imaging, measurements, and manipulation at the nanoscale. We present recent results based on experimental analysis that yield new insights into the dynamics of CNT probe tips in tapping mode AFM. Experimental measurements are presented of the frequency response and dynamic amplitude-distance data of a high-aspect-ratio multi-walled (MW) CNT tip. Higher harmonics of the microcantilever are measured in frequency ranges corresponding to attractive regime and the repulsive regime where the CNT buckles dynamically. Surface scanning is performed using a MWCNT tip on a SiO(2) grating to verify the imaging instabilities associated with MWCNT buckling when used with normal control schemes in the tapping mode. Lastly, the choice of optimal setpoints for tapping mode control using CNT tip are discussed using the experimental results.
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Affiliation(s)
- S I Lee
- School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-1288, USA
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Nguyen CV, So C, Stevens RM, Li Y, Delziet L, Sarrazin P, Meyyappan M. High Lateral Resolution Imaging with Sharpened Tip of Multi-Walled Carbon Nanotube Scanning Probe. J Phys Chem B 2004. [DOI: 10.1021/jp0361529] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cattien V. Nguyen
- Center for Nanotechnology, NASA Ames Research Center, MS 229-1, Moffett Field, California 94035
| | - Chris So
- Center for Nanotechnology, NASA Ames Research Center, MS 229-1, Moffett Field, California 94035
| | - Ramsey M. Stevens
- Center for Nanotechnology, NASA Ames Research Center, MS 229-1, Moffett Field, California 94035
| | - You Li
- Center for Nanotechnology, NASA Ames Research Center, MS 229-1, Moffett Field, California 94035
| | - Lance Delziet
- Center for Nanotechnology, NASA Ames Research Center, MS 229-1, Moffett Field, California 94035
| | - Philippe Sarrazin
- Center for Nanotechnology, NASA Ames Research Center, MS 229-1, Moffett Field, California 94035
| | - M. Meyyappan
- Center for Nanotechnology, NASA Ames Research Center, MS 229-1, Moffett Field, California 94035
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