51
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Hou H, Bai X, Xing C, Gu N, Zhang B, Tang J. Aptamer-based cantilever array sensors for oxytetracycline detection. Anal Chem 2013; 85:2010-4. [PMID: 23350586 DOI: 10.1021/ac3037574] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a new method for specific detection of oxytetracycline (OTC) at nanomolar concentrations based on a microfabricated cantilever array. The sensing cantilevers in the array are functionalized with self-assembled monolayers (SAMs) of OTC-specific aptamer, which acts as a recognition molecule for OTC. While the reference cantilevers in the array are functionalized with 6-mercapto-1-hexanol SAMs to eliminate the influence of environmental disturbances. The cantilever sensor shows a good linear relationship between the deflection amplitude and the OTC concentration in the range of 1.0-100 nM. The detection limit of the cantilever array sensor is as low as 0.2 nM, which is comparable to some traditional methods. Other antibiotics such as doxycycline and tetracycline do not cause significant deflection of the cantilevers. It is demonstrated that the cantilever array sensors can be used as a powerful tool to detect drugs with high sensitivity and selectivity.
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Analysis of detection enhancement using microcantilevers with long-slit-based sensors. SENSORS 2013; 13:681-702. [PMID: 23296327 PMCID: PMC3574697 DOI: 10.3390/s130100681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 12/26/2012] [Accepted: 12/30/2012] [Indexed: 11/17/2022]
Abstract
The present work analyzes theoretically and verifies the advantage of utilizing rectangular microcantilevers with long-slits in microsensing applications. The deflection profile of these microcantilevers is compared with that of typical rectangular microcantilevers under the action of dynamic disturbances. Various force-loading conditions are considered. The theory of linear elasticity for thin beams is used to obtain the deflection-related quantities. The disturbance in these quantities is obtained based on wave propagation and beam vibration theories. It is found that detections of rectangular microcantilevers with long-slits based on maximum slit opening length can be more than 100 times the deflections of typical rectangular microcantilevers. Moreover, the disturbance (noise effect) in the detection quantities of the microcantilever with long-slits is found to be always smaller than that of typical microcantilevers, regardless of the wavelength, force amplitude, and the frequency of the dynamic disturbance. Eventually, the detection quantities of the microcantilever with long-slits are found to be almost unaffected by dynamic disturbances, as long as the wavelengths of these disturbances are larger than 3.5 times the microcantilever width. Finally, the present work recommends implementation of microcantilevers with long-slits as microsensors in robust applications, including real analyte environments and out of laboratory testing.
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53
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Alvarez M, Fariña D, Escuela AM, Sendra JR, Lechuga LM. Development of a surface plasmon resonance and nanomechanical biosensing hybrid platform for multiparametric reading. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:015008. [PMID: 23387688 DOI: 10.1063/1.4789430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have developed a hybrid platform that combines two well-known biosensing technologies based on quite different transducer principles: surface plasmon resonance and nanomechanical sensing. The new system allows the simultaneous and real-time detection of two independent parameters, refractive index change (Δn), and surface stress change (Δσ) when a biomolecular interaction takes place. Both parameters have a direct relation with the mass coverage of the sensor surface. The core of the platform is a common fluid cell, where the solution arrives to both sensor areas at the same time and under the same conditions (temperature, velocity, diffusion, etc.).The main objective of this integration is to achieve a better understanding of the physical behaviour of the transducers during sensing, increasing the information obtained in real time in one single experiment. The potential of the hybrid platform is demonstrated by the detection of DNA hybridization.
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Affiliation(s)
- Mar Alvarez
- Nanobiosensors and Bioanalytical Applications Group, Research Center on Nanoscience and Nanotechnology CIN2(CSIC) and CIBER-BBN, 08193 Bellaterra, Barcelona, Spain.
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54
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Wagman M, Medalion S, Rabin Y. Anomalous Swelling of Polymer Monolayers by Water Vapor. Macromolecules 2012. [DOI: 10.1021/ma3018553] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michal Wagman
- Department of Physics and Institute of Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Shlomi Medalion
- Department of Physics and Institute of Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Yitzhak Rabin
- Department of Physics and Institute of Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
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55
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Lee G, Lee H, Nam K, Han JH, Yang J, Lee SW, Yoon DS, Eom K, Kwon T. Nanomechanical characterization of chemical interaction between gold nanoparticles and chemical functional groups. NANOSCALE RESEARCH LETTERS 2012; 7:608. [PMID: 23113991 PMCID: PMC3502532 DOI: 10.1186/1556-276x-7-608] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Accepted: 10/19/2012] [Indexed: 05/23/2023]
Abstract
We report on how to quantify the binding affinity between a nanoparticle and chemical functional group using various experimental methods such as cantilever assay, PeakForce quantitative nanomechanical property mapping, and lateral force microscopy. For the immobilization of Au nanoparticles (AuNPs) onto a microscale silicon substrate, we have considered two different chemical functional molecules of amine and catecholamine (here, dopamine was used). It is found that catecholamine-modified surface is more effective for the functionalization of AuNPs onto the surface than the amine-modified surface, which has been shown from our various experiments. The dimensionless parameter (i.e., ratio of binding affinity) introduced in this work from such experiments is useful in quantitatively depicting such binding affinity, indicating that the binding affinity and stability between AuNPs and catecholamine is approximately 1.5 times stronger than that between amine and AuNPs. Our study sheds light on the experiment-based quantitative characterization of the binding affinity between nanomaterial and chemical groups, which will eventually provide an insight into how to effectively design the functional material using chemical groups.
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Affiliation(s)
- Gyudo Lee
- Institute for Molecular Sciences, Seoul, 120-749, Republic of Korea
- Department of Biomedical Engineering, Yonsei University, Wonju, 220-710, Republic of Korea
| | - Hyungbeen Lee
- Department of Biomedical Engineering, Yonsei University, Wonju, 220-710, Republic of Korea
| | - Kihwan Nam
- Institute for Molecular Sciences, Seoul, 120-749, Republic of Korea
- Department of Biomedical Engineering, Yonsei University, Wonju, 220-710, Republic of Korea
| | - Jae-Hee Han
- Department of Energy IT, Gachon University, Seongnam, Gyeonggi-do, 461-701, Republic of Korea
| | - Jaemoon Yang
- Department of Radiology, College of Medicine, Yonsei University, Seoul, 120-749, Republic of Korea
| | - Sang Woo Lee
- Department of Biomedical Engineering, Yonsei University, Wonju, 220-710, Republic of Korea
| | - Dae Sung Yoon
- Department of Biomedical Engineering, Yonsei University, Wonju, 220-710, Republic of Korea
| | - Kilho Eom
- Institute for Molecular Sciences, Seoul, 120-749, Republic of Korea
- Department of Biomedical Engineering, Yonsei University, Wonju, 220-710, Republic of Korea
| | - Taeyun Kwon
- Institute for Molecular Sciences, Seoul, 120-749, Republic of Korea
- Department of Biomedical Engineering, Yonsei University, Wonju, 220-710, Republic of Korea
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56
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Yoo YK, Chae MS, Kang JY, Kim TS, Hwang KS, Lee JH. Multifunctionalized cantilever systems for electronic nose applications. Anal Chem 2012; 84:8240-5. [PMID: 22947095 DOI: 10.1021/ac3015615] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Multiple target detection using a cantilever is essential for biosensor, chemical sensor, and electronic nose systems. We report a novel microcantilever array chip that includes four microreaction chambers in a chip, which consequently contains four different functionalized surfaces for multitarget detection. For model tests, we designed microcantilever chips and demonstrated the ability of binding of 2,4-dinitrotoluene (DNT) targets onto four different surfaces. We used peptide receptors that are known to have highly selective binding. By simply using four microreaction chambers, we immobilized DNT specific peptide (HPNFSKYILHQRC; SP), DNT nonspecific peptide (TSMLLMSPKHQAC; NSP), and self-assembled monolayer (SAM) as well as a bare cantilever. After flowing DNT gases through the cantilever chip, we could monitor the four different binding signals simultaneously. The shifts in NSP provided information as a negative control because it contained information of temperature fluctuations and mechanical vibration from gas flow. By utilizing the differential signal of the SP and NSP, we acquired 7.5 Hz in resonant responses that corresponds with 160 part per billion (ppb) DNT concentration, showing the exact binding response by eliminating the inevitable thermal noise, vibration noise, as well as humidity effects on the peptide surface.
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Affiliation(s)
- Yong Kyoung Yoo
- Department of Electrical Engineering, Kwangwoon University, 447-1, Wolgye, Nowon, Seoul, 139-701, Korea
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57
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Chen Y, Xu P, Li X. Axial-Stressed Piezoresistive Nanobeam for Ultrahigh Chemomechanical Sensitivity to Molecular Adsorption. Anal Chem 2012; 84:8184-9. [DOI: 10.1021/ac301388k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ying Chen
- State Key
Lab of Transducer Technology, and Science
and Technology on Microsystem Lab, Shanghai Institute of Microsystem
and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Pengcheng Xu
- State Key
Lab of Transducer Technology, and Science
and Technology on Microsystem Lab, Shanghai Institute of Microsystem
and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Xinxin Li
- State Key
Lab of Transducer Technology, and Science
and Technology on Microsystem Lab, Shanghai Institute of Microsystem
and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
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58
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Yu H, Yang T, Chen Y, Xu P, Lee DW, Li X. Chemo-Mechanical Joint Detection with Both Dynamic and Static Microcantilevers for Interhomologue Molecular Identification. Anal Chem 2012; 84:6679-85. [DOI: 10.1021/ac3011022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haitao Yu
- State Key Lab of Transducer
Technology and Science and Technology on Micro-system Lab, Shanghai
Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Tiantian Yang
- State Key Lab of Transducer
Technology and Science and Technology on Micro-system Lab, Shanghai
Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
- School of Digital Media, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Ying Chen
- State Key Lab of Transducer
Technology and Science and Technology on Micro-system Lab, Shanghai
Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Pengcheng Xu
- State Key Lab of Transducer
Technology and Science and Technology on Micro-system Lab, Shanghai
Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Dong-Weon Lee
- School of Mechanical Systems Engineering, Chonnam National University, Gwang-Ju, 500757, Korea
| | - Xinxin Li
- State Key Lab of Transducer
Technology and Science and Technology on Micro-system Lab, Shanghai
Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
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59
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Federici S, Oliviero G, Maiolo D, Depero LE, Colombo I, Bergese P. On the thermodynamics of biomolecule surface transformations. J Colloid Interface Sci 2012; 375:1-11. [DOI: 10.1016/j.jcis.2012.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 02/03/2012] [Accepted: 02/04/2012] [Indexed: 02/06/2023]
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60
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Zhang J, Lang HP, Yoshikawa G, Gerber C. Optimization of DNA hybridization efficiency by pH-driven nanomechanical bending. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6494-6501. [PMID: 22439593 DOI: 10.1021/la205066h] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The accessibility and binding affinity of DNA are two key parameters affecting the hybridization efficiency in surface-based biosensor technologies. Better accessibility will result in a higher hybridization efficiency. Often, mixed ssDNA and mercaptohexanol monolayers are used to increase the hybridization efficiency and accessibility of surface-bound oligonucleotides to complementary target DNA. Here, no mercaptohexanol monolayer was used. We demonstrate by differential microcantilever deflection measurements at different pH that the hybridization efficiency peaks between pH 7.5 and 8.5. At low pH 4.5, hydration and electrostatic forces led to tensile surface stress, implying the reduced accessibility of the bound ssDNA probe for hybridization. In contrast, at high pH 8.5, the steric interaction between neighboring ssDNA strands was decreased by higher electrostatic repulsive forces, bending the microcantilever away from the gold surface to provide more space for the target DNA. Cantilever deflection scales with pH-dependent surface hybridization efficiency because of high target DNA accessibility. Hence, by changing the pH, the hybridization efficiency is adjusted.
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Affiliation(s)
- Jiayun Zhang
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
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61
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Eom K, Jung H, Lee G, Park J, Nam K, Lee SW, Yoon DS, Yang J, Kwon T. Nanomechanical actuation driven by light-induced DNA fuel. Chem Commun (Camb) 2012; 48:955-7. [DOI: 10.1039/c1cc12893k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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62
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Analysis of deflection enhancement using epsilon assembly microcantilevers based sensors. SENSORS 2011; 11:9260-74. [PMID: 22163694 PMCID: PMC3231271 DOI: 10.3390/s111009260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 09/21/2011] [Accepted: 09/23/2011] [Indexed: 11/16/2022]
Abstract
The present work analyzes theoretically and verifies the advantage of utilizing ɛ-microcantilever assemblies in microsensing applications. The deflection profile of these innovative ɛ-assembly microcantilevers is compared with that of the rectangular microcantilever and modified triangular microcantlever. Various force-loading conditions are considered. The theorem of linear elasticity for thin beams is used to obtain the deflections. The obtained defections are validated against an accurate numerical solution utilizing finite element method with maximum deviation less than 10 percent. It is found that the ɛ-assembly produces larger deflections than the rectangular microcantilever under the same base surface stress and same extension length. In addition, the ɛ-microcantilever assembly is found to produce larger deflection than the modified triangular microcantilever. This deflection enhancement is found to increase as the ɛ-assembly's free length decreases for various types of force loading conditions. Consequently, the ɛ-microcantilever is shown to be superior in microsensing applications as it provides favorable high detection capability with a reduced susceptibility to external noises. Finally, this work paves a way for experimentally testing the ɛ-assembly to show whether detective potential of microsensors can be increased.
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63
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Lee J, Chunara R, Shen W, Payer K, Babcock K, Burg TP, Manalis SR. Suspended microchannel resonators with piezoresistive sensors. LAB ON A CHIP 2011; 11:645-51. [PMID: 21180703 DOI: 10.1039/c0lc00447b] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Precision frequency detection has enabled the suspended microchannel resonator (SMR) to weigh single living cells, single nanoparticles, and adsorbed protein layers in fluid. To date, the SMR resonance frequency has been determined optically, which requires the use of an external laser and photodiode and cannot be easily arrayed for multiplexed measurements. Here we demonstrate the first electronic detection of SMR resonance frequency by fabricating piezoresistive sensors using ion implantation into single crystal silicon resonators. To validate the piezoresistive SMR, buoyant mass histograms of budding yeast cells and a mixture of 1.6, 2.0, 2.5, and 3.0 µm diameter polystyrene beads are measured. For SMRs designed to weigh micron-sized particles and cells, the mass resolution achieved with piezoresistive detection (∼3.4 fg in a 1 kHz bandwidth) is comparable to what can be achieved by the conventional optical-lever detector. Eliminating the need for expensive and delicate optical components will enable new uses for the SMR in both multiplexed and field deployable applications.
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Affiliation(s)
- J Lee
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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64
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Batzias FA, Siontorou CG, Spanidis PMP. Designing a reliable leak bio-detection system for natural gas pipelines. JOURNAL OF HAZARDOUS MATERIALS 2011; 186:35-58. [PMID: 21177031 DOI: 10.1016/j.jhazmat.2010.09.115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 08/23/2010] [Accepted: 09/10/2010] [Indexed: 05/30/2023]
Abstract
Monitoring of natural gas (NG) pipelines is an important task for economical/safety operation, loss prevention and environmental protection. Timely and reliable leak detection of gas pipeline, therefore, plays a key role in the overall integrity management for the pipeline system. Owing to the various limitations of the currently available techniques and the surveillance area that needs to be covered, the research on new detector systems is still thriving. Biosensors are worldwide considered as a niche technology in the environmental market, since they afford the desired detector capabilities at low cost, provided they have been properly designed/developed and rationally placed/networked/maintained by the aid of operational research techniques. This paper addresses NG leakage surveillance through a robust cooperative/synergistic scheme between biosensors and conventional detector systems; the network is validated in situ and optimized in order to provide reliable information at the required granularity level. The proposed scheme is substantiated through a knowledge based approach and relies on Fuzzy Multicriteria Analysis (FMCA), for selecting the best biosensor design that suits both, the target analyte and the operational micro-environment. This approach is illustrated in the design of leak surveying over a pipeline network in Greece.
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Affiliation(s)
- F A Batzias
- University Piraeus, Department of Industrial Management & Technology, Piraeus, Greece.
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65
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Hilt JZ, Gupta AK, Bashir R, Peppas NA. A Microsensor Based on a Microcantilever Patterned with an Environmentally Sensitive Hydrogel. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-729-u4.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractA process was developed for patterning thin films of environmentally sensitive hydrogels onto silicon microcantilevers. Microcantilevers have been shown to be ultra-sensitive transducers for chemical, physical, and biological microsensors. By patterning environmentally sensitive hydrogels onto silicon microcantilevers, novel microsensors were prepared for MEMS and BioMEMS applications. Specifically, a cross-linked poly(methacrylic acid) (PMAA) network containing significant amounts of poly(ethylene glycol) dimethacrylate (PEGDMA) was studied. This hydrogel exhibits a swelling dependence on pH. By increasing the environmental pH above the pKa of PMAA to cause ionization of the carboxylic acid groups, electrostatic repulsion is produced along the main polymer chain causing the polymer network to expand and swell. Therefore, a pH change induces swelling or shrinking of the polymer network and creates stress on the microcantilever surface causing it to bend. In this study, silicon microcantilevers were fabricated on p-type (100) SOI wafers. Covalent adhesion was gained between the polymer and the silicon surface through the modification of the silicon surface with γ-methacryloxypropyl trimethoxysilane. Hydrogels were patterned onto the silicon microcantilevers utilizing a mask aligner to allow for precise positioning. The micropatterned hydrogels were analyzed using optical microscopy and profilometry. The bending response of patterned cantilevers with a change in environmental pH was observed, providing proof-of-concept for a MEMS/BioMEMS sensor based on microcantilevers patterned with environmentally sensitive hydrogels.
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66
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67
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Zhang NH, Chen JZ, Li JJ, Tan ZQ. Mechanical properties of DNA biofilms adsorbed on microcantilevers in label-free biodetections. Biomaterials 2010; 31:6659-66. [DOI: 10.1016/j.biomaterials.2010.05.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 05/17/2010] [Indexed: 11/30/2022]
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Abstract
Highly sensitive, label-free biodetection methods have applications in both the fundamental research and healthcare diagnostics arenas. Therefore, the development of new transduction methods and the improvement of the existing methods will significantly impact these areas. A brief overview of the different types of biosensors and the critical parameters governing their performance will be given. Additionally, a more in-depth discussion of optical devices, surface functionalization methods to increase device specificity, and fluidic techniques to improve sample delivery will be reviewed.
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Affiliation(s)
- Heather K Hunt
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA.
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69
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Liu KW, Biswal SL. Using Microcantilevers to Study the Interactions of Lipid Bilayers with Solid Surfaces. Anal Chem 2010; 82:7527-32. [DOI: 10.1021/ac100083v] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kai-Wei Liu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005
| | - Sibani Lisa Biswal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005
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70
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Gong P, Wang K, Liu Y, Shepard K, Levicky R. Molecular mechanisms in morpholino-DNA surface hybridization. J Am Chem Soc 2010; 132:9663-71. [PMID: 20572663 PMCID: PMC2920048 DOI: 10.1021/ja100881a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthetic nucleic acid mimics provide opportunity for redesigning the specificity and affinity of hybridization with natural DNA or RNA. Such redesign is of great interest for diagnostic applications where it can enhance the desired signal against a background of competing interactions. This report compares hybridization of DNA analyte strands with morpholinos (MOs), which are uncharged nucleic acid mimics, to the corresponding DNA-DNA case in solution and on surfaces. In solution, MO-DNA hybridization is found to be independent of counterion concentration, in contrast to DNA-DNA hybridization. On surfaces, when immobilized MO or DNA "probe" strands hybridize with complementary DNA "targets" from solution, both the MO-DNA and DNA-DNA processes depend on ionic strength but exhibit qualitatively different behaviors. At lower ionic strengths, MO-DNA surface hybridization exhibits hallmarks of kinetic limitations when separation between hybridized probe sites becomes comparable to target dimensions, whereas extents of DNA-DNA surface hybridization are instead consistent with limits imposed by buildup of surface (Donnan) potential. The two processes also fundamentally differ at high ionic strength, under conditions when electrostatic effects are weak. Here, variations in probe coverage have a much diminished impact on MO-DNA than on DNA-DNA hybridization for similarly crowded surface conditions. These various observations agree with a structural model of MO monolayers in which MO-DNA duplexes segregate to the buffer interface while unhybridized probes localize near the solid support. A general perspective is presented on using uncharged DNA analogues, which also include compounds such as peptide nucleic acids (PNA), in surface hybridization applications.
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Affiliation(s)
- Ping Gong
- Seventh Sense Biosystems Inc., 101 Binney Street, Cambridge, Massachusetts 02142, USA
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71
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Application of peptide nucleic acid towards development of nanobiosensor arrays. Bioelectrochemistry 2010; 79:153-61. [PMID: 20356802 DOI: 10.1016/j.bioelechem.2010.02.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 01/20/2010] [Accepted: 02/23/2010] [Indexed: 11/20/2022]
Abstract
Peptide nucleic acid (PNA) is the modified DNA or DNA analogue with a neutral peptide backbone instead of a negatively charged sugar phosphate. PNA exhibits chemical stability, resistant to enzymatic degradation inside living cell, recognizing specific sequences of nucleic acid, formation of stable hybrid complexes like PNA/DNA/PNA triplex, strand invasion, extraordinary thermal stability and ionic strength, and unique hybridization relative to nucleic acids. These unique physicobiochemical properties of PNA enable a new mode of detection, which is a faster and more reliable analytical process and finds applications in the molecular diagnostics and pharmaceutical fields. Besides, a variety of unique characteristic features, PNAs replace DNA as a probe for biomolecular tool in the molecular genetic diagnostics, cytogenetics, and various pharmaceutical potentials as well as for the development of sensors/arrays/chips and many more investigation purposes. This review paper discusses the various current aspects related with PNAs, making a new hot device in the commercial applications like nanobiosensor arrays.
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72
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Nanotechnology for early cancer detection. SENSORS 2010; 10:428-55. [PMID: 22315549 PMCID: PMC3270850 DOI: 10.3390/s100100428] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 12/14/2009] [Accepted: 12/29/2009] [Indexed: 12/19/2022]
Abstract
Vast numbers of studies and developments in the nanotechnology area have been conducted and many nanomaterials have been utilized to detect cancers at early stages. Nanomaterials have unique physical, optical and electrical properties that have proven to be very useful in sensing. Quantum dots, gold nanoparticles, magnetic nanoparticles, carbon nanotubes, gold nanowires and many other materials have been developed over the years, alongside the discovery of a wide range of biomarkers to lower the detection limit of cancer biomarkers. Proteins, antibody fragments, DNA fragments, and RNA fragments are the base of cancer biomarkers and have been used as targets in cancer detection and monitoring. It is highly anticipated that in the near future, we might be able to detect cancer at a very early stage, providing a much higher chance of treatment.
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73
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Chen T, Chang DP, Liu T, Desikan R, Datar R, Thundat T, Berger R, Zauscher S. Glucose-responsive polymer brushes for microcantilever sensing. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b925583d] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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74
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75
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Lee SM, Hwang KS, Yoon HJ, Yoon DS, Kim SK, Lee YS, Kim TS. Sensitivity enhancement of a dynamic mode microcantilever by stress inducer and mass inducer to detect PSA at low picogram levels. LAB ON A CHIP 2009; 9:2683-2690. [PMID: 19704984 DOI: 10.1039/b902922b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report two types of signal enhancement strategy derived from the origin of mechanical response, surface stress and mass, of the dynamic mode microcantilever for the detection of PSA at low picogram scales (low femtomolar concentration). The PSA detection at extremely low concentration levels is crucial to the early detection of relapses of prostate cancer after the radical prostatectomy and the detection of breast cancer in patient's serum. There is a clear need for the ultrasensitive detection of PSA via simple and rapid diagnostic tools. From the motives, to increase the sensitivity of the microcantilever, PSA polyclonal antibody (PSA pAb) as an additional surface stress inducer and PSA polyclonal antibody-conjugated silica nanoparticles (pAb-SiNPs) as a mass inducer have been applied to the PSA-captured microcantilevers. From two types of sandwich assay, we could confirm the sensitivity enhancement effects (2 approximately 4 times enhanced at the same concentrations) enough to detect PSA at low picogram levels (LOD of 1 pg/mL or below). Moreover, surface stress due to steric interactions between epitope-specific monoclonal antibodies was assessed to support a signal amplification strategy by stress inducer, and the reduction of signal enhancement due to stiffness increase by the mass inducer was studied to clarify the sensitivity enhancement of the microcantilever by mass inducer.
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Affiliation(s)
- Sang-Myung Lee
- Nano-Bio Research Center, Korea Institute of Science and Technology, 39-1, Haweolgog-Dong, Seongbuk-Gu, Seoul, 136-791, Republic of Korea
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76
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Arroyo-Hernández M, Tamayo J, Costa-Krämer JL. Stress and DNA assembly differences on cantilevers gold coated by resistive and e-beam evaporation techniques. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10633-10638. [PMID: 19694416 DOI: 10.1021/la900696f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Changes in the sign of differential surface stress of gold-coated cantilevers produced by thiol-derivatized single-stranded DNA immobilization are observed, depending on the method used to deposit the gold. While the DNA immobilization on e-beam gold-coated cantilevers produces a compressive differential surface stress in the metallic layer, the opposite is observed for resistively coated cantilevers under the same immobilization conditions. The gold films exhibit quite a similar morphology, and the immobilization differences seem to be related to the charge state of the metallic layer surface. This in turn produces a different distribution of the orientation of the DNA strands on the gold layer. A tentative explanation for the observed effect is proposed.
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Affiliation(s)
- M Arroyo-Hernández
- Instituto de Microelectrónica de Madrid, IMM-CNM-CSIC, Isaac Newton 8, PTM, 28760 Tres Cantos, Madrid, Spain.
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77
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Experimental and computational characterization of biological liquid crystals: a review of single-molecule bioassays. Int J Mol Sci 2009; 10:4009-4032. [PMID: 19865530 PMCID: PMC2769145 DOI: 10.3390/ijms10094009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 09/01/2009] [Accepted: 09/07/2009] [Indexed: 12/15/2022] Open
Abstract
Quantitative understanding of the mechanical behavior of biological liquid crystals such as proteins is essential for gaining insight into their biological functions, since some proteins perform notable mechanical functions. Recently, single-molecule experiments have allowed not only the quantitative characterization of the mechanical behavior of proteins such as protein unfolding mechanics, but also the exploration of the free energy landscape for protein folding. In this work, we have reviewed the current state-of-art in single-molecule bioassays that enable quantitative studies on protein unfolding mechanics and/or various molecular interactions. Specifically, single-molecule pulling experiments based on atomic force microscopy (AFM) have been overviewed. In addition, the computational simulations on single-molecule pulling experiments have been reviewed. We have also reviewed the AFM cantilever-based bioassay that provides insight into various molecular interactions. Our review highlights the AFM-based single-molecule bioassay for quantitative characterization of biological liquid crystals such as proteins.
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78
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Zhang NH, Chen JZ. Mechanical properties of double-stranded DNA biolayers immobilized on microcantilever under axial compression. J Biomech 2009; 42:1483-1487. [PMID: 19500790 DOI: 10.1016/j.jbiomech.2009.03.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 11/22/2008] [Accepted: 03/28/2009] [Indexed: 11/30/2022]
Affiliation(s)
- Neng-Hui Zhang
- Department of Mechanics, College of Sciences, Shanghai University, Shanghai 200444, China; Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China.
| | - Jian-Zhong Chen
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China
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79
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Norman LL, Badia A. Redox actuation of a microcantilever driven by a self-assembled ferrocenylundecanethiolate monolayer: an investigation of the origin of the micromechanical motion and surface stress. J Am Chem Soc 2009; 131:2328-37. [PMID: 19166296 DOI: 10.1021/ja808400s] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electrochemically induced motion of free-standing microcantilevers is attracting interest as micro/nanoactuators and robotic devices. The development and implementation of these cantilever-based actuating technologies requires a molecular-level understanding of the origin of the surface stress that causes the cantilever to bend. Here, we report a detailed study of the electroactuation dynamics of gold-coated microcantilevers modified with a model, redox-active ferrocenylundecanethiolate self-assembled monolayer (FcC(11)SAu SAM). The microcantilever transducer enabled the observation of the redox transformation of the surface-confined ferrocene. Oxidation of the FcC(11)SAu SAM in perchlorate electrolyte generated a compressive surface stress change of -0.20 +/- 0.04 N m(-1), and cantilever deflections ranging from approximately 0.8 microm to approximately 60 nm for spring constants between approximately 0.01 and approximately 0.8 N m(-1). A comparison of the charge-normalized surface stress of the FcC(11)SAu cantilever with values published for the electrochemical oxidation of polyaniline- and polypyrrole-coated cantilevers reveals a striking 10- to 100-fold greater stress for the monomolecular FcC(11)SAu system compared to the conducting polymer multilayers used for electroactuation. The larger stress change observed for the FcC(11)SAu microcantilever is attributable to steric constraints in the close-packed FcC(11)SAu SAM and an efficient coupling between the chemisorbed FcC(11)S- monolayer and the Au-coated microcantilever transducer (vs physisorbed conducting polymers). The microcantilever deflection vs quantity of electrogenerated ferrocenium obtained in cyclic voltammetry and potential step/hold experiments, as well as the surface stress changes obtained for mixed FcC(11)S-/C(11)SAu SAMs containing different populations of clustered vs isolated ferrocenes, have permitted us to establish the molecular basis of stress generation. Our results strongly suggest that the redox-induced deflection of a FcC(11)SAu microcantilever is caused by a monolayer volume expansion resulting from collective reorientational motions induced by the complexation of perchlorate ions to the surface-immobilized ferroceniums. The cantilever responds to the lateral pressure exerted by an ensemble of reorienting ferrocenium-bearing alkylthiolates upon each other rather than individual anion pairing events. This finding has general implications for using SAM-modified microcantilevers as (bio)sensors because it indicates that the cantilever responds to collective in-plane molecular interactions rather than reporting individual (bio)chemical events.
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Affiliation(s)
- Lana L Norman
- FQRNT Center for Self-Assembled Chemical Structures, Regroupement québécois sur les matériaux de pointe, and Department of Chemistry, Université de Montréal, QC H3C 3J7 Canada
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80
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Juluri BK, Kumar AS, Liu Y, Ye T, Yang YW, Flood AH, Fang L, Stoddart JF, Weiss PS, Huang TJ. A mechanical actuator driven electrochemically by artificial molecular muscles. ACS NANO 2009; 3:291-300. [PMID: 19236063 DOI: 10.1021/nn8002373] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A microcantilever, coated with a monolayer of redox-controllable, bistable [3]rotaxane molecules (artificial molecular muscles), undergoes reversible deflections when subjected to alternating oxidizing and reducing electrochemical potentials. The microcantilever devices were prepared by precoating one surface with a gold film and allowing the palindromic [3]rotaxane molecules to adsorb selectively onto one side of the microcantilevers, utilizing thiol-gold chemistry. An electrochemical cell was employed in the experiments, and deflections were monitored both as a function of (i) the scan rate (< or =20 mV s(-1)) and (ii) the time for potential step experiments at oxidizing (>+0.4 V) and reducing (<+0.2 V) potentials. The different directions and magnitudes of the deflections for the microcantilevers, which were coated with artificial molecular muscles, were compared with (i) data from nominally bare microcantilevers precoated with gold and (ii) those coated with two types of control compounds, namely, dumbbell molecules to simulate the redox activity of the palindromic bistable [3]rotaxane molecules and inactive 1-dodecanethiol molecules. The comparisons demonstrate that the artificial molecular muscles are responsible for the deflections, which can be repeated over many cycles. The microcantilevers deflect in one direction following oxidation and in the opposite direction upon reduction. The approximately 550 nm deflections were calculated to be commensurate with forces per molecule of approximately 650 pN. The thermal relaxation that characterizes the device's deflection is consistent with the double bistability associated with the palindromic [3]rotaxane and reflects a metastable contracted state. The use of the cooperative forces generated by these self-assembled, nanometer-scale artificial molecular muscles that are electrically wired to an external power supply constitutes a seminal step toward molecular-machine-based nanoelectromechanical systems (NEMS).
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Affiliation(s)
- Bala Krishna Juluri
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802-6812, USA
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81
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Ansari MZ, Cho C. A Study on Increasing Sensitivity of Rectangular Microcantilevers Used in Biosensors. SENSORS 2008; 8:7530-7544. [PMID: 27873943 PMCID: PMC3787459 DOI: 10.3390/s8117530] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 11/10/2008] [Accepted: 11/10/2008] [Indexed: 12/02/2022]
Abstract
This study proposes a new microcantilever design with a rectangular hole at the fixed end of the cantilever that is more sensitive than conventional ones. A commercial finite element analysis software ANSYS is used to analyze it. The Stoney equation is first used to calculate the surface stress induced moment, and then applied to the microcantilever free end to produce deflection. The stress analysis of the proposed and conventional designs is performed, followed by dynamic analysis of the proposed design. We found that the Sader equation is more accurate than Stoney in predicting cantilever deflections, and that for increasing the sensitivity of a microcantilever biosensor increasing the cantilever thickness is more practical.
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Affiliation(s)
- Mohd Zahid Ansari
- Department of Mechanical Engineering, Inha University, 253 Yonghyun-dong, Nam-Ku, Incheon, 402-751 Republic of Korea.
| | - Chongdu Cho
- Department of Mechanical Engineering, Inha University, 253 Yonghyun-dong, Nam-Ku, Incheon, 402-751 Republic of Korea.
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82
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Cerruti M, Fissolo S, Carraro C, Ricciardi C, Majumdar A, Maboudian R. Poly(ethylene glycol) monolayer formation and stability on gold and silicon nitride substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:10646-10653. [PMID: 18729528 DOI: 10.1021/la801357v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Poly(ethylene glycol) (PEG) self-assembled monolayers (SAMs) are extensively used to modify substrates to prevent nonspecific protein adsorption and to increase hydrophilicity. X-ray photoelectron spectroscopy analysis, complemented by water contact angle measurements, is employed to investigate the formation and stability upon aging and heating of PEG monolayers formed on gold and silicon nitride substrates. In particular, thiolated PEG monolayers on gold, with and without the addition of an undecylic spacer chain, and PEG monolayers formed with oxysilane precursors on silicon nitride have been probed. It is found that PEG-thiol SAMs are degraded after less than two weeks of exposure to air and when heated at temperatures as low as 120 degrees C. On the contrary, PEG-silane SAMs are stable for more than two weeks, and fewer molecules are desorbed even after two months of aging, compared to those desorbed in two weeks from the PEG-thiol SAMs. A strongly bound hydration layer is found on PEG-silane SAMs aged for two months. Heating PEG-silane SAMs to temperatures as high as 160 degrees C improves the quality of the monolayer, desorbing weakly bound contaminants. The differences in stability between PEG-thiol SAMs and PEG-silane SAMs are ascribed to the different types of bonding to the surface and to the fact that the thiol-Au bond can be easily oxidized, thus causing desorption of PEG molecules from the surface.
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Affiliation(s)
- Marta Cerruti
- Department of Chemical Engineering, University of California at Berkeley, Berkeley, California 94720, USA
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83
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Raorane DA, Lim MD, Chen FF, Craik CS, Majumdar A. Quantitative and label-free technique for measuring protease activity and inhibition using a microfluidic cantilever array. NANO LETTERS 2008; 8:2968-74. [PMID: 18720973 PMCID: PMC2663003 DOI: 10.1021/nl8019455] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We report the use of a SiN x based gold coated microcantilever array to quantitatively measure the activity and inhibition of a model protease immobilized on its surface. Trypsin was covalently bound to the gold surface of the microcantilever using a synthetic spacer, and the remaining exposed silicon nitride surface was passivated with silanated polyethylene glycol. The nanoscale cantilever motions induced by trypsin during substrate turnover were quantitatively measured using an optical laser-deflection technique. These microcantilever deflections directly correlated with the degree of protease turnover of excess synthetic fibronectin substrate ( K M = 0.58 x 10 (-6) M). Inhibition of surface-immobilized trypsin by soybean trypsin inhibitor (SBTI) was also observed using this system.
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Affiliation(s)
- Digvijay A Raorane
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
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84
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Cha M, Shin J, Kim JH, Kim I, Choi J, Lee N, Kim BG, Lee J. Biomolecular detection with a thin membrane transducer. LAB ON A CHIP 2008; 8:932-937. [PMID: 18497914 DOI: 10.1039/b719101d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a thin membrane transducer (TMT) that can detect nucleic acid based biomolecular reactions including DNA hybridization and protein recognition by aptamers. Specific molecular interactions on an extremely thin and flexible membrane surface cause the deflection of the membrane due to surface stress change which can be measured by a compact capacitive circuit. A gold-coated thin PDMS membrane assembled with metal patterned glass substrate is used to realize the capacitive detection. It is demonstrated that perfect match and mismatch hybridizations can be sharply discriminated with a 16-mer DNA oligonucleotide immobilized on the gold-coated surface. While the mismatched sample caused little capacitance change, the perfectly matched sample caused a well-defined capacitance decrease vs. time due to an upward deformation of the membrane by a compressive surface stress. Additionally, the TMT demonstrated the single nucleotide polymorphism (SNP) capabilities which enabled a detection of mismatching base pairs in the middle of the sequence. It is intriguing that the increase of capacitance, therefore a downward deflection due to tensile stress, was observed with the internal double mismatch hybridization. We further present the detection of thrombin protein through ligand-receptor type recognition with 15-mer thrombin aptamer as a receptor. Key aspects of this detection such as the effect of concentration variation are investigated. This capacitive thin membrane transducer presents a completely new approach for detecting biomolecular reactions with high sensitivity and specificity without molecular labelling and optical measurement.
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Affiliation(s)
- Misun Cha
- School of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Shinlim, Kwanak, Seoul, 151-742, Korea
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85
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Abstract
This review will provide a general introduction to the field of cantilever biosensors by discussing the basic principles and the basic technical background necessary to understand and evaluate this class of sensors. Microfabricated cantilever sensors respond to changes in their environment or changes on their surface with a mechanical bending in the order of nanometers which can easily be detected. They are able to detect pH and temperature changes, the formation of self-assembled monolayers, DNA hybridization, antibody-antigen interactions, or the adsorption of bacteria. The review will focus on the surface stress mode of microfabricated cantilever arrays and their application as biosensors in molecular life science. A general background on biosensors, an overview of the different modes of operation of cantilever sensors and some details on sensor functionalization will be given. Finally, key experiments and current theoretical efforts to describe the surface stress mode of cantilever sensors will be discussed.
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Affiliation(s)
- Jürgen Fritz
- Jacobs University Bremen, School of Engineering and Science, Campus Ring 1, 28759 Bremen, Germany.
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86
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Feng JT, Zhao YP. Influence of different amount of Au on the wetting behavior of PDMS membrane. Biomed Microdevices 2008; 10:65-72. [PMID: 17659443 DOI: 10.1007/s10544-007-9110-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polydimethylsiloxane (PDMS) has been widely used as a base material for bio-MEMS/NEMS devices. It is difficult for PDMS to transfer and spread aqueous solution as a kind of highly hydrophobic material. Therefore, surface modification is necessary for PDMS to make it hydrophilic. In this paper, a method of hydrophilization of PDMS surface is proposed. Gold is sputtered to the PDMS substrate by sputter coater in different average thicknesses. Relationship between the average thickness of gold on the PDMS substrate and the contact angle of the surface was studied. It was found that even gold of average thickness less than 1 nm can result in about 25 degrees change of contact angle. AFM is also used to get topographic information of PDMS surface coated with gold. Three cases are classified with different amount of Au: (1) Heterogeneous zone; (2) Transition zone; (3) Film zone. For heterogeneous zone, a simple model about heterogeneous phase wetting is put forward to interpret this phenomenon.
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Affiliation(s)
- Jiang-Tao Feng
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, 15 Beisihuanxi Road, Beijing 100080, China
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87
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Comrie JE, Huck WTS. Exploring Actuation and Mechanotransduction Properties of Polymer Brushes. Macromol Rapid Commun 2008. [DOI: 10.1002/marc.200700682] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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88
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Nordström M, Keller S, Lillemose M, Johansson A, Dohn S, Haefliger D, Blagoi G, Havsteen-Jakobsen M, Boisen A. SU-8 Cantilevers for Bio/chemical Sensing; Fabrication, Characterisation and Development of Novel Read-out Methods. SENSORS 2008; 8:1595-1612. [PMID: 27879783 PMCID: PMC3663014 DOI: 10.3390/s8031595] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 03/03/2008] [Indexed: 11/16/2022]
Abstract
Here, we present the activities within our research group over the last five yearswith cantilevers fabricated in the polymer SU-8. We believe that SU-8 is an interestingpolymer for fabrication of cantilevers for bio/chemical sensing due to its simple processingand low Young's modulus. We show examples of different integrated read-out methodsand their characterisation. We also show that SU-8 cantilevers have a reduced sensitivity tochanges in the environmental temperature and pH of the buffer solution. Moreover, weshow that the SU-8 cantilever surface can be functionalised directly with receptormolecules for analyte detection, thereby avoiding gold-thiol chemistry.
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Affiliation(s)
- Maria Nordström
- MIC - Department of Micro and Nanotechnology, Technical University of Denmark, DTU building 345 East, DK-2800 Kongens Lyngby, Denmark.
| | - Stephan Keller
- MIC - Department of Micro and Nanotechnology, Technical University of Denmark, DTU building 345 East, DK-2800 Kongens Lyngby, Denmark
| | - Michael Lillemose
- MIC - Department of Micro and Nanotechnology, Technical University of Denmark, DTU building 345 East, DK-2800 Kongens Lyngby, Denmark
| | | | - Søren Dohn
- MIC - Department of Micro and Nanotechnology, Technical University of Denmark, DTU building 345 East, DK-2800 Kongens Lyngby, Denmark
| | | | - Gabriela Blagoi
- MIC - Department of Micro and Nanotechnology, Technical University of Denmark, DTU building 345 East, DK-2800 Kongens Lyngby, Denmark
| | - Mogens Havsteen-Jakobsen
- MIC - Department of Micro and Nanotechnology, Technical University of Denmark, DTU building 345 East, DK-2800 Kongens Lyngby, Denmark
| | - Anja Boisen
- MIC - Department of Micro and Nanotechnology, Technical University of Denmark, DTU building 345 East, DK-2800 Kongens Lyngby, Denmark
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89
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Johnson CJ, Zhukovsky N, Cass AEG, Nagy JM. Proteomics, nanotechnology and molecular diagnostics. Proteomics 2008; 8:715-30. [DOI: 10.1002/pmic.200700665] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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90
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Goeders KM, Colton JS, Bottomley LA. Microcantilevers: Sensing Chemical Interactions via Mechanical Motion. Chem Rev 2008; 108:522-42. [DOI: 10.1021/cr0681041] [Citation(s) in RCA: 269] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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91
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Zhou F, Biesheuvel PM, Choi EY, Shu W, Poetes R, Steiner U, Huck WTS. Polyelectrolyte brush amplified electroactuation of microcantilevers. NANO LETTERS 2008; 8:725-730. [PMID: 18269260 DOI: 10.1021/nl073157z] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This paper describes the electroactuation of microcantilevers coated on one side with cationic polyelectrolyte brushes. We observed very strong cantilever deflection by alternating the potential on the cantilever between +0.5 and -0.5 V at frequencies up to 0.25 Hz. The actuation resulted from significant increases in the expansive stresses in the polymer brush layer at both negative and positive potentials. However, the deflection at negative bias was significantly larger. We have developed a theoretical framework that correlates conformational changes of the polymer chains in the brush layer with the reorganization of ions due to the potential bias. The model predicts a strong increase in the polymer volume fraction, close to the interface, which results in large expansive stresses that bend the cantilever at negative potentials. The model also predicts that the actuation responds much stronger to negative potentials than positive potentials, as observed in the experiments.
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Affiliation(s)
- Feng Zhou
- Melville Laboratory for Polymer Synthesis, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW United Kingdom
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92
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Ferrari M. The mathematical engines of nanomedicine. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:20-25. [PMID: 18165947 DOI: 10.1002/smll.200701144] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- Mauro Ferrari
- The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, 1825 Pressler, Suite 537D, Houston, TX 77031, USA.
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93
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Abstract
This chapter describes the application of nano- and micro-electromechanical systems (NEMs and MEMs), and more specifically microcantilever structures, as transducers for highly sensitive biosensors. In these devices, named as ‘nanomechanical biosensors,’ a biomolecular interaction produces a change in the mechanical behavior of the transducer (a movement at nanometer scale), which can be measured and analyzed in real time. Microcantilevers translate the molecular recognition of biomolecules into a nanomechanical motion that is commonly coupled to an optical read-out system. This chapter discusses the main aspects regarding the physics of microcantilever as well the optical read-out techniques. It reviews the state-of-the-art, and discusses the prospective future directions of this new family of biosensors. Nanomechanical sensors are derived from the microfabricated cantilevers used in atomic force microscopy (AFM) and are based on the bending or resonance change induced in the cantilever when a biomolecular interaction takes place on one of its surfaces. The cantilever response depends on its mechanical properties, which are determined mainly by their spring constant and resonance frequency. Both parameters depend on the cantilever material and its geometry. The increasing number of applications of microcantilevers as biosensors has established these systems as a versatile platform for real-time and in situmeasurements of physical, chemical, and biochemical interactions. Further research is banked upon to provide information for increasing the biosensor sensitivity.
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94
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Affiliation(s)
- Audrey Sassolas
- Laboratoire de Génie Enzymatique et Biomoléculaire, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, 43 Boulevard du 11 Novembre 1918, Villeurbanne F-69622, France, UMR5246, Centre National de La Recherche Scientifque, Villeurbanne F-69622, France, Université de Lyon, Lyon F-69622, France, Université Lyon 1, Lyon F-69622, France, Institut National des Sciences Appliquées de Lyon, École d'Ingénieurs, Villeurbanne F-69621, France, and École Supérieure Chimie Physique Électronique de Lyon,
| | - Béatrice D. Leca-Bouvier
- Laboratoire de Génie Enzymatique et Biomoléculaire, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, 43 Boulevard du 11 Novembre 1918, Villeurbanne F-69622, France, UMR5246, Centre National de La Recherche Scientifque, Villeurbanne F-69622, France, Université de Lyon, Lyon F-69622, France, Université Lyon 1, Lyon F-69622, France, Institut National des Sciences Appliquées de Lyon, École d'Ingénieurs, Villeurbanne F-69621, France, and École Supérieure Chimie Physique Électronique de Lyon,
| | - Loïc J. Blum
- Laboratoire de Génie Enzymatique et Biomoléculaire, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, 43 Boulevard du 11 Novembre 1918, Villeurbanne F-69622, France, UMR5246, Centre National de La Recherche Scientifque, Villeurbanne F-69622, France, Université de Lyon, Lyon F-69622, France, Université Lyon 1, Lyon F-69622, France, Institut National des Sciences Appliquées de Lyon, École d'Ingénieurs, Villeurbanne F-69621, France, and École Supérieure Chimie Physique Électronique de Lyon,
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95
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Kinsella JM, Ivanisevic A. Biosensing: Taking charge of biomolecules. NATURE NANOTECHNOLOGY 2007; 2:596-597. [PMID: 18654379 DOI: 10.1038/nnano.2007.313] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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96
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Waggoner PS, Craighead HG. Micro- and nanomechanical sensors for environmental, chemical, and biological detection. LAB ON A CHIP 2007; 7:1238-55. [PMID: 17896006 DOI: 10.1039/b707401h] [Citation(s) in RCA: 242] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Micro- and nanoelectromechanical systems, including cantilevers and other small scale structures, have been studied for sensor applications. Accurate sensing of gaseous or aqueous environments, chemical vapors, and biomolecules have been demonstrated using a variety of these devices that undergo static deflections or shifts in resonant frequency upon analyte binding. In particular, biological detection of viruses, antigens, DNA, and other proteins is of great interest. While the majority of currently used detection schemes are reliant on biomarkers, such as fluorescent labels, time, effort, and chemical activity could be saved by developing an ultrasensitive method of label-free mass detection. Micro- and nanoscale sensors have been effectively applied as label-free detectors. In the following, we review the technologies and recent developments in the field of micro- and nanoelectromechanical sensors with particular emphasis on their application as biological sensors and recent work towards integrating these sensors in microfluidic systems.
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Affiliation(s)
- Philip S Waggoner
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
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97
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Maraldo D, Rijal K, Campbell G, Mutharasan R. Method for Label-Free Detection of Femtogram Quantities of Biologics in Flowing Liquid Samples. Anal Chem 2007; 79:2762-70. [PMID: 17309231 DOI: 10.1021/ac0621726] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rapid (approximately 10 min) measurement of very low concentration of pathogens (approximately 10 cells/mL) and protein (approximately fg/mL) has widespread use in medical diagnostics, monitoring biothreat agents, and in a broader context as a research method. For low-level pathogen, we currently use culture enrichment methods and, thus, rapid analysis is not possible. For low protein concentration, no direct method is currently available. We report here a novel macrocantilever design whose high-order resonant mode near 1 MHz exhibits mass detection sensitivity of 10 cells/mL for cells and 100 fg/mL for protein. The sensor is 1x3 mm and uses a piezoelectric layer for both actuation and sensing resonance. Sample is flowed (approximately 1 mL/min) past the antibody-immobilized sensor, and as antigen binds to the sensor, resonance frequency decreases in proportion to antigen concentration. The sensor showed selectivity to the pathogen even though copious nonpathogenic variant was simultaneously present.
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Affiliation(s)
- David Maraldo
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA
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98
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Kay ER, Leigh DA, Zerbetto F. Synthetic molecular motors and mechanical machines. Angew Chem Int Ed Engl 2007; 46:72-191. [PMID: 17133632 DOI: 10.1002/anie.200504313] [Citation(s) in RCA: 2050] [Impact Index Per Article: 120.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The widespread use of controlled molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular systems, which by and large rely upon electronic and chemical effects to carry out their functions, and the machines of the macroscopic world, which utilize the synchronized movements of smaller parts to perform specific tasks. This is a scientific area of great contemporary interest and extraordinary recent growth, yet the notion of molecular-level machines dates back to a time when the ideas surrounding the statistical nature of matter and the laws of thermodynamics were first being formulated. Here we outline the exciting successes in taming molecular-level movement thus far, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion. We also highlight some of the issues and challenges that still need to be overcome.
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Affiliation(s)
- Euan R Kay
- School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK
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99
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Kohale S, Molina SM, Weeks BL, Khare R, Hope-Weeks LJ. Monitoring the formation of self-assembled monolayers of alkanedithiols using a micromechanical cantilever sensor. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:1258-63. [PMID: 17241042 DOI: 10.1021/la062441n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Using a micromechanical cantilever device, the surface stress induced during the growth of alkanedithiol (HS(CH2)nSH) monolayers on gold in solution is continuously monitored and reported. Adsorption of alkanedithiols of varying chain lengths is observed and compared to each other, as well as to the adsorption of hydroxyalkanethiols (HS(CH2)nOH) and alkanethiols (HS(CH2)nCH3). The results have revealed a significant change in surface stress on the basis of the chain length of the alkanedithiol. The long-chain (n > 10) alkanedithiol adsorption imposes a tensile stress on the gold-coated surface of the cantilever rather than the compressive stress exhibited by both alkanethiols and short-chain dithiols. Our results suggest a phenomenon in which the two thiols of the alkanedithiol adsorb onto the gold surface forming a loop inducing a tensile stress on the cantilever for long chain lengths. This study shows that micromechanical cantilever sensors can be very valuable tools in the exploration and characterization of self-assembled monolayers.
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Affiliation(s)
- Swapnil Kohale
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
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100
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Kwon HS, Han KC, Hwang KS, Lee JH, Kim TS, Yoon DS, Yang EG. Development of a peptide inhibitor-based cantilever sensor assay for cyclic adenosine monophosphate-dependent protein kinase. Anal Chim Acta 2007; 585:344-9. [PMID: 17386684 DOI: 10.1016/j.aca.2006.12.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2006] [Revised: 12/05/2006] [Accepted: 12/20/2006] [Indexed: 11/17/2022]
Abstract
A highly sensitive nanomechanical cantilever sensor assay based on an electrical measurement has been developed for detecting activated cyclic adenosine monophosphate (cyclic AMP)-dependent protein kinase (PKA). Employing a peptide derived from the heat-stable protein kinase inhibitor (PKI), a magnetic bead system was first selected as a vehicle to immobilize the PKI-(5-24) peptide for capturing PKA catalytic subunit and the activity assay was applied for indirectly assessing the binding. Synergistic interactions of adenosine triphosphate (ATP) and the peptide inhibitor with the kinase were then investigated by a solution phase capillary electrophoretic assay, and by surface plasmon resonance technology which involved immobilization of the peptide inhibitor. After systemically evaluated by a homogeneous direct binding assay, the ATP-dependent recognition of the catalytic subunit of PKA by PKI-(5-24) was successfully transferred on to the nanomechanical cantilevers at protein concentrations of 6.6 pM-66 nM, exhibiting much higher sensitivity and wider dynamic range than the conventional activity assay. Thus, direct assessment of activated kinases using the cantilever sensor system functionalized with specific peptide inhibitors holds great promise in analytical applications and clinical medicine.
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Affiliation(s)
- Hyuk-Sung Kwon
- Life Sciences Division, Korea Institute of Science and Technology, PO Box 131, Cheongryang, Seoul, Republic of Korea
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