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Pujol-Vila F, Escudero P, Güell-Grau P, Pascual-Izarra C, Villa R, Alvarez M. Direct Color Observation of Light-Driven Molecular Conformation-Induced Stress. SMALL METHODS 2022; 6:e2101283. [PMID: 35174993 DOI: 10.1002/smtd.202101283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Although usually complex to handle, nanomechanical sensors are exceptional, label-free tools for monitoring molecular conformational changes, which makes them of paramount importance in understanding biomolecular interactions. Herein, a simple and inexpensive mechanical imaging approach based on low-stiffness cantilevers with structural coloration (mechanochromic cantilevers (MMC)) is demonstrated, able to monitor and quantify molecular conformational changes with similar sensitivity to the classical optical beam detection method of cantilever-based sensors (≈4.6 × 10-3 N m-1 ). This high sensitivity is achieved by using a white light and an RGB camera working in the reflection configuration. The sensor performance is demonstrated by monitoring the UV-light induced reversible conformational changes of azobenzene molecules coating. The trans-cis isomerization of the azobenzene molecules induces a deflection of the cantilevers modifying their diffracted color, which returns to the initial state by cis-trans relaxation. Interestingly, the mechanical imaging enables a simultaneous 2D mapping of the response thus enhancing the spatial resolution of the measurements. A tight correlation is found between the color output and the cantilever's deflection and curvature angle (sensitivities of 5 × 10-3 Hue µm-1 and 1.5 × 10-1 Hue (°)-1 ). These findings highlight the suitability of low-stiffness MMC as an enabling technology for monitoring molecular changes with unprecedented simplicity, high-throughput capability, and functionalities.
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Affiliation(s)
- Ferran Pujol-Vila
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | - Pedro Escudero
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Facultad de Ingeniería y Tecnologías de la Información y la Comunicación, Universidad Tecnológica Indoamérica, Ambato, 180103, Ecuador
| | - Pau Güell-Grau
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | | | - Rosa Villa
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Networking Research Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018, Madrid, Spain
| | - Mar Alvarez
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Networking Research Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018, Madrid, Spain
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2
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Huber F, Lang HP, Lang D, Wüthrich D, Hinić V, Gerber C, Egli A, Meyer E. Rapid and Ultrasensitive Detection of Mutations and Genes Relevant to Antimicrobial Resistance in Bacteria. GLOBAL CHALLENGES (HOBOKEN, NJ) 2021; 5:2000066. [PMID: 33552553 PMCID: PMC7857129 DOI: 10.1002/gch2.202000066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/06/2020] [Indexed: 06/12/2023]
Abstract
The worldwide emergence of multidrug-resistant (MDR) bacteria is associated with significant morbidity, mortality, and healthcare costs. Rapid and accurate diagnostic methods to detect antibiotic resistance are critical for antibiotic stewardship and infection control measurements. Here a cantilever nanosensor-based diagnostic assay is shown to detect single nucleotide polymorphisms (SNPs) and genes associated with antibiotic resistance in Gram negative (Pseudomonas aeruginosa) and positive (Enterococcus faecium) bacteria, representing frequent causes for MDR infections. Highly specific RNA capture probes for SNPs (ampRD135G or ampRG154R ) or resistance genes (vanA, vanB, and vanD) allow to detect the binding of bacterial RNA within less than 5 min. Serial dilutions of bacterial RNA indicate an unprecedented sensitivity of 10 fg µL-1 total RNA corresponding to less than ten bacterial cells for SNPs and 1 fg µL-1 total RNA for vanD detection equivalent to single bacterial cell sensitivity.
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Affiliation(s)
- François Huber
- Swiss Nanoscience Institute (SNI)Department of PhysicsUniversity of BaselKlingelbergstrasse 82BaselCH‐4056Switzerland
| | - Hans Peter Lang
- Swiss Nanoscience Institute (SNI)Department of PhysicsUniversity of BaselKlingelbergstrasse 82BaselCH‐4056Switzerland
| | - Daniela Lang
- Clinical Bacteriology and Mycology, University Hospital BaselApplied Microbiology ResearchDepartment of BiomedicineUniversity of BaselPetersgraben 4Basel4031Switzerland
| | - Daniel Wüthrich
- Clinical Bacteriology and Mycology, University Hospital BaselApplied Microbiology ResearchDepartment of BiomedicineUniversity of BaselPetersgraben 4Basel4031Switzerland
| | - Vladimira Hinić
- Clinical Bacteriology and Mycology, University Hospital BaselApplied Microbiology ResearchDepartment of BiomedicineUniversity of BaselPetersgraben 4Basel4031Switzerland
| | - Christoph Gerber
- Swiss Nanoscience Institute (SNI)Department of PhysicsUniversity of BaselKlingelbergstrasse 82BaselCH‐4056Switzerland
| | - Adrian Egli
- Clinical Bacteriology and Mycology, University Hospital BaselApplied Microbiology ResearchDepartment of BiomedicineUniversity of BaselPetersgraben 4Basel4031Switzerland
| | - Ernst Meyer
- Swiss Nanoscience Institute (SNI)Department of PhysicsUniversity of BaselKlingelbergstrasse 82BaselCH‐4056Switzerland
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3
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Basu AK, Basu A, Bhattacharya S. Micro/Nano fabricated cantilever based biosensor platform: A review and recent progress. Enzyme Microb Technol 2020; 139:109558. [PMID: 32732024 DOI: 10.1016/j.enzmictec.2020.109558] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 03/21/2020] [Accepted: 03/26/2020] [Indexed: 12/24/2022]
Abstract
Recent trends in biosensing research have motivated scientists and research professionals to investigate the development of miniaturized bioanalytical devices to make them portable, label-free and smaller in size. The performance of the cantilever-based devices which is one of the very important domains of sensitive field level detection has improved significantly with the development of new micro/nanofabrication technologies and surface functionalization techniques. The cantilevers have scaled down to Nano from micro-level and have become exceptionally sensitive and also have some anomalous associated properties due to the scale. In this review we have discussed about fundamental principles of cantilever operation, detection methods, and previous, present and future approaches of study through cantilever-based sensing platform. Other than that, we have also discussed the past major bio-sensing efforts through micro/nano cantilevers and about recent progress in the field.
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Affiliation(s)
- Aviru Kumar Basu
- Design Programme, Indian Institute of Technology, Kanpur, U.P. 208016, India; Microsystems Fabrication Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, U.P. 208016, India; Singapore University of Technology and Design, 487372 Singapore
| | - Adreeja Basu
- Department of Biological Sciences, St. John's University, New York, N.Y 11439, USA
| | - Shantanu Bhattacharya
- Design Programme, Indian Institute of Technology, Kanpur, U.P. 208016, India; Microsystems Fabrication Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, U.P. 208016, India.
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4
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Grogan C, Amarandei G, Lawless S, Pedreschi F, Lyng F, Benito-Lopez F, Raiteri R, Florea L. Silicon Microcantilever Sensors to Detect the Reversible Conformational Change of a Molecular Switch, Spiropyan. SENSORS (BASEL, SWITZERLAND) 2020; 20:E854. [PMID: 32041095 PMCID: PMC7039217 DOI: 10.3390/s20030854] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/22/2020] [Accepted: 01/31/2020] [Indexed: 12/13/2022]
Abstract
The high sensitivity of silicon microcantilever sensors has expanded their use in areas ranging from gas sensing to bio-medical applications. Photochromic molecules also represent promising candidates for a large variety of sensing applications. In this work, the operating principles of these two sensing methods are combined in order to detect the reversible conformational change of a molecular switch, spiropyran. Thus, arrays of silicon microcantilever sensors were functionalized with spiropyran on the gold covered side and used as test microcantilevers. The microcantilever deflection response was observed, in five sequential cycles, as the transition from the spiropyran (SP) (CLOSED) to the merocyanine (MC) (OPEN) state and vice-versa when induced by UV and white light LED sources, respectively, proving the reversibility capabilities of this type of sensor. The microcantilever deflection direction was observed to be in one direction when changing to the MC state and in the opposite direction when changing back to the SP state. A tensile stress was induced in the microcantilever when the SP to MC transition took place, while a compressive stress was observed for the reverse transition. These different type of stresses are believed to be related to the spatial conformational changes induced in the photochromic molecule upon photo-isomerisation.
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Affiliation(s)
- Catherine Grogan
- School of Physics & Clinical & Optometric Sciences, Technological University of Dublin, Kevin Street, D08NF82 Dublin, Ireland; (C.G.); (G.A.); (F.P.); (F.L.)
| | - George Amarandei
- School of Physics & Clinical & Optometric Sciences, Technological University of Dublin, Kevin Street, D08NF82 Dublin, Ireland; (C.G.); (G.A.); (F.P.); (F.L.)
| | - Shauna Lawless
- Insight Centre for Data Analytics, National Centre for Sensor Research, Dublin City University, 9 Dublin, Ireland;
| | - Fran Pedreschi
- School of Physics & Clinical & Optometric Sciences, Technological University of Dublin, Kevin Street, D08NF82 Dublin, Ireland; (C.G.); (G.A.); (F.P.); (F.L.)
| | - Fiona Lyng
- School of Physics & Clinical & Optometric Sciences, Technological University of Dublin, Kevin Street, D08NF82 Dublin, Ireland; (C.G.); (G.A.); (F.P.); (F.L.)
- FOCAS Institute, Technological University Dublin, Camden Row, 8 Dublin, Ireland
| | - Fernando Benito-Lopez
- Analytical Microsystems & Materials for Lab-on-a-Chip Group (AMMa-LOAC), Microfluidics Cluster UPV/EHU, Analytical Chemistry Department, University of the Basque Country UPV/EHU, 01006 Vitoria-Gasteiz, Spain;
| | - Roberto Raiteri
- Department of Informatics, Bioengineering, Robotics and System Engineering, University of Genova, 16145 Genova, Italy;
| | - Larisa Florea
- School of Chemistry & AMBER, the SFI Research Centre for Advanced Materials and BioEngineering Research, Trinity College Dublin, the University of Dublin, College Green, 2 Dublin, Ireland
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5
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Interaction of Extracellular Vesicles with Si Surface Studied by Nanomechanical Microcantilever Sensors. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8030404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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7
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Haag AL, Schumacher Z, Grutter P. Sensitivity measurement of a cantilever-based surface stress sensor. J Chem Phys 2016; 145:154704. [DOI: 10.1063/1.4964922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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8
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Huber F, Lang HP, Glatz K, Rimoldi D, Meyer E, Gerber C. Fast Diagnostics of BRAF Mutations in Biopsies from Malignant Melanoma. NANO LETTERS 2016; 16:5373-5377. [PMID: 27490749 DOI: 10.1021/acs.nanolett.6b01513] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
According to the American skin cancer foundation, there are more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung, and colon each year, and malignant melanoma represents its deadliest form. About 50% of all cases are characterized by a particular mutation BRAF(V600E) in the BRAF (Rapid Acceleration of Fibrosarcoma gene B) gene. Recently developed highly specific drugs are able to fight BRAF(V600E) mutated tumors but require diagnostic tools for fast and reliable mutation detection to warrant treatment efficiency. We completed a preliminary clinical trial applying cantilever array sensors to demonstrate identification of a BRAF(V600E) single-point mutation using total RNA obtained from biopsies of metastatic melanoma of diverse sources (surgical material either frozen or fixated with formalin and embedded in paraffin). The method is faster than the standard Sanger or pyrosequencing methods and comparably sensitive as next-generation sequencing. Processing time from biopsy to diagnosis is below 1 day and does not require PCR amplification, sequencing, and labels.
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Affiliation(s)
- François Huber
- Swiss Nanoscience Institute, Department of Physics, University of Basel , CH-4056 Basel, Switzerland
| | - Hans Peter Lang
- Swiss Nanoscience Institute, Department of Physics, University of Basel , CH-4056 Basel, Switzerland
| | - Katharina Glatz
- Institute of Pathology, University Hospital Basel , CH-4031 Basel, Switzerland
| | - Donata Rimoldi
- Ludwig Center for Cancer Research, University of Lausanne , CH-1066 Epalinges, Switzerland
| | - Ernst Meyer
- Swiss Nanoscience Institute, Department of Physics, University of Basel , CH-4056 Basel, Switzerland
| | - Christoph Gerber
- Swiss Nanoscience Institute, Department of Physics, University of Basel , CH-4056 Basel, Switzerland
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9
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Dultsev F, Kolosovsky E, Cooper M, Lomzov A, Pyshnyi D. QCM-based rapid analysis of DNA. SENSING AND BIO-SENSING RESEARCH 2015. [DOI: 10.1016/j.sbsr.2014.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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10
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Ferrier DC, Shaver MP, Hands PJW. Micro- and nano-structure based oligonucleotide sensors. Biosens Bioelectron 2015; 68:798-810. [PMID: 25655465 DOI: 10.1016/j.bios.2015.01.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/12/2015] [Accepted: 01/13/2015] [Indexed: 12/26/2022]
Abstract
This paper presents a review of micro- and nano-structure based oligonucleotide detection and quantification techniques. The characteristics of such devices make them very attractive for Point-of-Care or On-Site-Testing biosensing applications. Their small scale means that they can be robust and portable, their compatibility with modern CMOS electronics means that they can easily be incorporated into hand-held devices and their suitability for mass production means that, out of the different approaches to oligonucleotide detection, they are the most suitable for commercialisation. This review discusses the advantages of micro- and nano-structure based sensors and covers the various oligonucleotide detection techniques that have been developed to date. These include: Bulk Acoustic Wave and Surface Acoustic Wave devices, micro- and nano-cantilever sensors, gene Field Effect Transistors, and nanowire and nanopore based sensors. Oligonucleotide immobilisation techniques are also discussed.
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Affiliation(s)
- David C Ferrier
- School of Engineering, University of Edinburgh, Edinburgh EH9 3JL, UK
| | - Michael P Shaver
- School of Chemistry, David Brewster Road, University of Edinburgh, Edinburgh EH9 3FJ, UK
| | - Philip J W Hands
- School of Engineering, University of Edinburgh, Edinburgh EH9 3JL, UK.
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11
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Geryak R, Tsukruk VV. Reconfigurable and actuating structures from soft materials. SOFT MATTER 2014; 10:1246-63. [PMID: 24651547 DOI: 10.1039/c3sm51768c] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The recent interest in reconfigurable soft materials may lead to the next paradigm in the development of adaptive and actuating materials and structures. Actuating soft materials eventually can be precisely designed to show stimuli-sensing, multi-length scale actuation, tunable transport, programmed shape control and multifunctional orthogonal responses. Herein, we discuss the various advances in the emerging field of reconfigurable soft materials with a focus on the various parameters that can be modulated to control a complex system behavior. In particular, we detail approaches that use either long-range fields (i.e. electrical, magnetic) or changes in local thermodynamic parameters (e.g., solvent quality) in order to elicit a precise dimensional and controlled response. The theoretical underpinnings and practical considerations for different approaches are briefly presented alongside several illustrative examples from the recent studies. In the end, we summarize recent accomplishments, critical issues to consider, and give perspectives on the developments of this exciting research field.
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Affiliation(s)
- Ren Geryak
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
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12
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Thakur G, Jiang K, Lee D, Prashanthi K, Kim S, Thundat T. Investigation of pH-induced protein conformation changes by nanomechanical deflection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2109-2116. [PMID: 24512545 DOI: 10.1021/la403981t] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Broad-spectrum biosensing technologies examine sensor signals using biomarkers, such as proteins, DNA, antibodies, specific cells, and macromolecules, based on direct- or indirect-conformational changes. Here, we have investigated the pH-dependent conformational isomerization of human serum albumin (HSA) using microcantilevers as a sensing platform. Native and denatured proteins were immobilized on cantilever surfaces to understand the effect of pH on conformational changes of the protein with respect to the coupling ligand. Our results show that protonation and deprotonation of amino acid residues on proteins play a significant role in generating charge-induced cantilever deflection. Surface plasmon resonance (SPR) was employed as a complementary technique to validate the results.
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Affiliation(s)
- Garima Thakur
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 2 V4, Canada
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13
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Chandra H, Reddy PJ, Srivastava S. Protein microarrays and novel detection platforms. Expert Rev Proteomics 2014; 8:61-79. [DOI: 10.1586/epr.10.99] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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14
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Isolation of a new Pseudomonas halophila strain possess bacteriorhodopsin-like protein by a novel method for screening of photoactive protein producing bacteria. World J Microbiol Biotechnol 2013; 30:585-94. [PMID: 24002576 DOI: 10.1007/s11274-013-1453-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/01/2013] [Indexed: 10/26/2022]
Abstract
Bacteriorhodopsin (bR) is a transmembrane protein deposited in the purple membrane of Halobacterium salinarum which absorbs energy from photons to create a photo-induced proton gradient across the membrane. A bR molecule can be considered as a natural solar device transforming light into other types of energy and therefore is of interest for a wide range of applications including two and three-dimensional memory storage, optical data processing, artificial cells, holographic media, the artificial retina and photo sensor devices. H. salinarum is a slow-growing, halophilic Archaea present in red salt waters. The present study introduces a novel bR-like pigment from a new strain of Pseudomonas halophila (with registered accession number KC959570 in the NCBI databank) which has a very significant degree of light-dependent activity. This is the first report on the presence of functional bR-like protein in the Pseudomonas family. The isolate is a fast-growing, halophilic bacterium and is comparable with other photoactive protein producer microorganisms. Also, in the present study a novel isolation method for screen light-stimulating protein producing microorganisms is introduced. For this purpose 2,3,5-triphenyltetrazolium chloride (TTC) was employed for the first time as an artificial hydrogen acceptor in the proton-transfer processes. The TTC test is an easy and susceptible method for estimating hydrogen production during the proton transport process. This is the first report of the use of TTC for photo activity measurement and selection of bacteria containing light dependent proteins.
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15
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Nagai Y, Carbajal JD, White JH, Sladek R, Grutter P, Lennox RB. An electrochemically controlled microcantilever biosensor. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:9951-9957. [PMID: 23841706 DOI: 10.1021/la400975b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
An oligonucleotide-based electrochemically controlled gold-coated microcantilever biosensor that can transduce specific biomolecular interactions is reported. The derivatized microcantilever exhibits characteristic surface stress time course patterns in response to an externally applied periodic square wave potential. Experiments demonstrate that control of the surface charge density with an electrode potential is essential to producing a sensor that exhibits large, reproducible surface stress changes. The time course of surface stress changes are proposed to be linked to an electrochemically mediated competition between the adsorption of solution-based ions and the single- or double-stranded oligonucleotides tethered to the gold surface. A similar potential-actuated change in surface stress also results from the interaction between an oligonucleotide aptamer and its cognate ligand, demonstrating the broad applicability of this methodology.
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Affiliation(s)
- Yoshihiko Nagai
- Research Institute of the McGill University Health Centre, 2155 Guy Street, Montréal, Québec H3H 2R9, Canada
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16
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Huber F, Lang HP, Backmann N, Rimoldi D, Gerber C. Direct detection of a BRAF mutation in total RNA from melanoma cells using cantilever arrays. NATURE NANOTECHNOLOGY 2013; 8:125-129. [PMID: 23377457 DOI: 10.1038/nnano.2012.263] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/18/2012] [Indexed: 05/27/2023]
Abstract
Malignant melanoma, the deadliest form of skin cancer, is characterized by a predominant mutation in the BRAF gene. Drugs that target tumours carrying this mutation have recently entered the clinic. Accordingly, patients are routinely screened for mutations in this gene to determine whether they can benefit from this type of treatment. The current gold standard for mutation screening uses real-time polymerase chain reaction and sequencing methods. Here we show that an assay based on microcantilever arrays can detect the mutation nanomechanically without amplification in total RNA samples isolated from melanoma cells. The assay is based on a BRAF-specific oligonucleotide probe. We detected mutant BRAF at a concentration of 500 pM in a 50-fold excess of the wild-type sequence. The method was able to distinguish melanoma cells carrying the mutation from wild-type cells using as little as 20 ng µl(-1) of RNA material, without prior PCR amplification and use of labels.
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Affiliation(s)
- F Huber
- Swiss Nano Institute, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
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17
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Maiolo D, Mitola S, Leali D, Oliviero G, Ravelli C, Bugatti A, Depero LE, Presta M, Bergese P. Role of nanomechanics in canonical and noncanonical pro-angiogenic ligand/VEGF receptor-2 activation. J Am Chem Soc 2012; 134:14573-9. [PMID: 22860754 DOI: 10.1021/ja305816p] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Vascular endothelial growth factor receptor-2 (VEGFR2) is an endothelial cell receptor that plays a pivotal role in physiologic and pathologic angiogenesis and is a therapeutic target for angiogenesis-dependent diseases, including cancer. By leveraging on a dedicated nanomechanical biosensor, we investigated the nanoscale mechanical phenomena intertwined with VEGFR2 surface recognition by its prototypic ligand VEGF-A and its noncanonical ligand gremlin. We found that the two ligands bind the immobilized extracellular domain of VEGFR2 (sVEGFR2) with comparable binding affinity. Nevertheless, they interact with sVEGFR2 with different binding kinetics and drive different in-plane piconewton intermolecular forces, suggesting that the binding of VEGF-A or gremlin induces different conformational changes in sVEGFR2. These behaviors can be effectively described in terms of a different "nanomechanical affinity" of the two ligands for sVEGFR2, about 16-fold higher for VEGF-A with respect to gremlin. Such nanomechanical differences affect the biological activity driven by the two angiogenic factors in endothelial cells, as evidenced by a more rapid VEGFR2 clustering and a more potent mitogenic response triggered by VEGF-A in respect to gremlin. Together, these data point to surface intermolecular interactions on cell membrane between activated receptors as a key modulator of the intracellular signaling cascade.
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Affiliation(s)
- Daniele Maiolo
- Chemistry for Technologies Laboratory and INSTM, School of Engineering, University of Brescia, Via Branze, 38, 25123 Brescia, Italy
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18
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Arlett J, Myers E, Roukes M. Comparative advantages of mechanical biosensors. NATURE NANOTECHNOLOGY 2011; 6:203-15. [PMID: 21441911 PMCID: PMC3839312 DOI: 10.1038/nnano.2011.44] [Citation(s) in RCA: 438] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Mechanical interactions are fundamental to biology. Mechanical forces of chemical origin determine motility and adhesion on the cellular scale, and govern transport and affinity on the molecular scale. Biological sensing in the mechanical domain provides unique opportunities to measure forces, displacements and mass changes from cellular and subcellular processes. Nanomechanical systems are particularly well matched in size with molecular interactions, and provide a basis for biological probes with single-molecule sensitivity. Here we review micro- and nanoscale biosensors, with a particular focus on fast mechanical biosensing in fluid by mass- and force-based methods, and the challenges presented by non-specific interactions. We explain the general issues that will be critical to the success of any type of next-generation mechanical biosensor, such as the need to improve intrinsic device performance, fabrication reproducibility and system integration. We also discuss the need for a greater understanding of analyte-sensor interactions on the nanoscale and of stochastic processes in the sensing environment.
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Affiliation(s)
| | | | - M.L. Roukes
- Kavli Nanoscience Institute and Departments of Physics, Applied Physics, and Bioengineering, California Institute of Technology, MC 149-33 Pasadena, California 91125, USA.
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19
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Woo JR, Lim DK, Nam JM. Minimally stable nanoparticle-based colorimetric assay for simple, rapid, and sensitive antibody structure and activity evaluation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:648-655. [PMID: 21308990 DOI: 10.1002/smll.201002080] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Indexed: 05/30/2023]
Abstract
A gold nanoparticle-based colorimetric antibody structure and activity evaluation method is developed without using complicated and expensive instrumentation. In this assay, a minimum number of antibodies to stabilize nanoparticles are conjugated to gold nanoparticles to prepare minimally stable nanoparticle probes, and the addition of salt rapidly induced particle aggregation and a color change of the solution from red to blue (25-min assay time). It is found that the solution color change is affected by the degree of structural denaturation of antibodies, and the conformational change of antibodies affects the modification of antibodies to nanoparticles and particle stability. Importantly, the colorimetric method can be applied to different types of antibodies (IgG, IgA, and IgM) and it shows comparable or better structural sensitivity than conventional circular dichroism spectroscopy. Moreover, immunoassay results show that these structural changes of antibodies are highly correlated with their antigen-binding activities. Rapid particle aggregation and high structural sensitivity are achieved in this assay because particles are modified with a minimum number of antibodies to stabilize particles in solution. This nanoparticle-based colorimetric method could be useful in evaluating the structural and activity changes of an array of antibodies in an easy, rapid, and sensitive manner.
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Affiliation(s)
- Jung-Reem Woo
- Department of Chemistry, Seoul National University, 599 Gwanak-ro, Sillim-dong, Gwanak-gu,Seoul, 151-747, South Korea
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Sasaki T, Demura M, Kato N, Mukai Y. Sensitive Detection of Protein−Lipid Interaction Change on Bacteriorhodopsin Using Dodecyl β-d-Maltoside. Biochemistry 2011; 50:2283-90. [DOI: 10.1021/bi101993s] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takanori Sasaki
- School of Science and Technology, Meiji University, Tama-ku, Kawasaki-shi, Kanagawa 214-8571, Japan
| | - Makoto Demura
- Faculty of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Noritaka Kato
- School of Science and Technology, Meiji University, Tama-ku, Kawasaki-shi, Kanagawa 214-8571, Japan
| | - Yuri Mukai
- School of Science and Technology, Meiji University, Tama-ku, Kawasaki-shi, Kanagawa 214-8571, Japan
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Backmann N, Kappeler N, Braun T, Huber F, Lang HP, Gerber C, Lim RYH. Sensing surface PEGylation with microcantilevers. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2010; 1:3-13. [PMID: 21977390 PMCID: PMC3045929 DOI: 10.3762/bjnano.1.2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 09/06/2010] [Indexed: 05/28/2023]
Abstract
Polymers are often used to modify surface properties to control interfacial processes. Their sensitivity to solvent conditions and ability to undergo conformational transitions makes polymers attractive in tailoring surface properties with specific functionalities leading to applications in diverse areas ranging from tribology to colloidal stability and medicine. A key example is polyethylene glycol (PEG), which is widely used as a protein-resistant coating given its low toxicity and biocompatibility. We report here a microcantilever-based sensor for the in situ characterization of PEG monolayer formation on Au using the "grafting to" approach. Moreover, we demonstrate how microcantilevers can be used to monitor conformational changes in the grafted PEG layer in different solvent conditions. This is supported by atomic force microscope (AFM) images and force-distance curve measurements of the microcantilever chip surface, which show that the grafted PEG undergoes a reversible collapse when switching between good and poor solvent conditions, respectively.
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Affiliation(s)
- Natalija Backmann
- National Centre of Competence in Research in Nanoscale Science, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Natascha Kappeler
- National Centre of Competence in Research in Nanoscale Science, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Thomas Braun
- Center for Cellular Imaging and Nanoanalytics, Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - François Huber
- National Centre of Competence in Research in Nanoscale Science, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Hans-Peter Lang
- National Centre of Competence in Research in Nanoscale Science, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Christoph Gerber
- National Centre of Competence in Research in Nanoscale Science, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
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Ray S, Mehta G, Srivastava S. Label-free detection techniques for protein microarrays: prospects, merits and challenges. Proteomics 2010; 10:731-48. [PMID: 19953541 PMCID: PMC7167936 DOI: 10.1002/pmic.200900458] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Protein microarrays, on which thousands of discrete proteins are printed, provide a valuable platform for functional analysis of the proteome. They have been widely used for biomarker discovery and to study protein–protein interactions. The accomplishments of DNA microarray technology, which had enabled massive parallel studies of gene expression, sparked great interest for the development of protein microarrays to achieve similar success at the protein level. Protein microarray detection techniques are often classified as being label‐based and label‐free. Most of the microarray applications have employed labelled detection such as fluorescent, chemiluminescent and radioactive labelling. These labelling strategies have synthetic challenges, multiple label issues and may exhibit interference with the binding site. Therefore, development of sensitive, reliable, high‐throughput, label‐free detection techniques are now attracting significant attention. Label‐free detection techniques monitor biomolecular interactions and simplify the bioassays by eliminating the need for secondary reactants. Moreover, they provide quantitative information for the binding kinetics. In this article, we will review several label‐free techniques, which offer promising applications for the protein microarrays, and discuss their prospects, merits and challenges.
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Affiliation(s)
- Sandipan Ray
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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Abstract
Microfabricated cantilever sensors have attracted much interest in recent years as devices for the fast and reliable detection of small concentrations of molecules in air and solution. In addition to application of such sensors for gas and chemical-vapor sensing, for example as an artificial nose, they have also been employed to measure physical properties of tiny amounts of materials in miniaturized versions of conventional standard techniques such as calorimetry, thermogravimetry, weighing, photothermal spectroscopy, as well as for monitoring chemical reactions such as catalysis on small surfaces. In the past few years, the cantilever-sensor concept has been extended to biochemical applications and as an analytical device for measurements of biomaterials. Because of the label-free detection principle of cantilever sensors, their small size and scalability, this kind of device is advantageous for diagnostic applications and disease monitoring, as well as for genomics or proteomics purposes. The use of microcantilever arrays enables detection of several analytes simultaneously and solves the inherent problem of thermal drift often present when using single microcantilever sensors, as some of the cantilevers can be used as sensor cantilevers for detection, and other cantilevers serve as passivated reference cantilevers that do not exhibit affinity to the molecules to be detected.
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Affiliation(s)
- Bharat Bhushan
- Ohio State University, Nanoprobe Laboratory for Bio- and Nanotechnology and Biomimetics (NLB2), 201 W. 19th Avenue, 43210-1142 Columbus, OH USA
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Braun T, Ghatkesar MK, Backmann N, Grange W, Boulanger P, Letellier L, Lang HP, Bietsch A, Gerber C, Hegner M. Quantitative time-resolved measurement of membrane protein-ligand interactions using microcantilever array sensors. NATURE NANOTECHNOLOGY 2009; 4:179-85. [PMID: 19265848 DOI: 10.1038/nnano.2008.398] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 12/03/2008] [Indexed: 05/17/2023]
Abstract
Membrane proteins are central to many biological processes, and the interactions between transmembrane protein receptors and their ligands are of fundamental importance in medical research. However, measuring and characterizing these interactions is challenging. Here we report that sensors based on arrays of resonating microcantilevers can measure such interactions under physiological conditions. A protein receptor--the FhuA receptor of Escherichia coli--is crystallized in liposomes, and the proteoliposomes then immobilized on the chemically activated gold-coated surface of the sensor by ink-jet spotting in a humid environment, thus keeping the receptors functional. Quantitative mass-binding measurements of the bacterial virus T5 at subpicomolar concentrations are performed. These experiments demonstrate the potential of resonating microcantilevers for the specific, label-free and time-resolved detection of membrane protein-ligand interactions in a micro-array format.
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Affiliation(s)
- Thomas Braun
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices, Naughton Institute, Trinity College Dublin, Dublin 2, Ireland
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27
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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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28
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A biofunctional polymeric coating for microcantilever molecular recognition. Anal Chim Acta 2008; 630:161-7. [DOI: 10.1016/j.aca.2008.09.069] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 09/23/2008] [Accepted: 09/27/2008] [Indexed: 11/21/2022]
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Ghatkesar MK, Lang HP, Gerber C, Hegner M, Braun T. Comprehensive characterization of molecular interactions based on nanomechanics. PLoS One 2008; 3:e3610. [PMID: 18978938 PMCID: PMC2572191 DOI: 10.1371/journal.pone.0003610] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 10/08/2008] [Indexed: 11/18/2022] Open
Abstract
Molecular interaction is a key concept in our understanding of the biological mechanisms of life. Two physical properties change when one molecular partner binds to another. Firstly, the masses combine and secondly, the structure of at least one binding partner is altered, mechanically transducing the binding into subsequent biological reactions. Here we present a nanomechanical micro-array technique for bio-medical research, which not only monitors the binding of effector molecules to their target but also the subsequent effect on a biological system in vitro. This label-free and real-time method directly and simultaneously tracks mass and nanomechanical changes at the sensor interface using micro-cantilever technology. To prove the concept we measured lipid vesicle (approximately 748*10(6) Da) adsorption on the sensor interface followed by subsequent binding of the bee venom peptide melittin (2840 Da) to the vesicles. The results show the high dynamic range of the instrument and that measuring the mass and structural changes simultaneously allow a comprehensive discussion of molecular interactions.
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Affiliation(s)
- Murali Krishna Ghatkesar
- National Center of Competence for Research in Nanoscience, Institute of Physics, University of Basel, Basel, Switzerland
- California Institute of Technology, Pasadena, California, United States of America
| | - Hans-Peter Lang
- National Center of Competence for Research in Nanoscience, Institute of Physics, University of Basel, Basel, Switzerland
| | - Christoph Gerber
- National Center of Competence for Research in Nanoscience, Institute of Physics, University of Basel, Basel, Switzerland
| | - Martin Hegner
- CRANN, SFI Nanoscience Institute, Trinity College, University of Dublin, Dublin, Ireland
- * E-mail: (MH); (TB)
| | - Thomas Braun
- National Center of Competence for Research in Nanoscience, Institute of Physics, University of Basel, Basel, Switzerland
- CRANN, SFI Nanoscience Institute, Trinity College, University of Dublin, Dublin, Ireland
- * E-mail: (MH); (TB)
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Hemmersam AG, Rechendorff K, Foss M, Sutherland DS, Besenbacher F. Fibronectin adsorption on gold, Ti-, and Ta-oxide investigated by QCM-D and RSA modelling. J Colloid Interface Sci 2008; 320:110-6. [DOI: 10.1016/j.jcis.2007.11.047] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 10/15/2007] [Accepted: 11/02/2007] [Indexed: 10/22/2022]
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31
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Ji HF, Gao H, Buchapudi KR, Yang X, Xu X, Schulte MK. Microcantilever biosensors based on conformational change of proteins. Analyst 2008; 133:434-43. [PMID: 18365110 DOI: 10.1039/b713330h] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Microcantilevers (MCLs) hold a position as a cost-effective and highly sensitive sensor platform for medical diagnostics, environmental analysis and fast throughput analysis. MCLs are unique in that adsorption of analytes on the microcantilever (MCL) surface changes the surface characteristics of the MCL and results in bending of the MCL. Surface stress due to conformation change of proteins and other polymers has been a recent focus of MCL research. Since conformational changes in proteins can be produced through binding of anylates at specific receptor sites, MCLs that respond to conformational change induced surface stress are promising as transducers of chemical information and are ideal for developing microcantilever-based biosensors. The MCL can also potentially be used to investigate conformational change of proteins induced by non-binding events such as post-translational modification and changes in temperature or pH. This review will provide an overview of MCL biosensors based on conformational change of proteins bound to the MCL surface. The models include conformational change of proteins, proteins on membranes, enzymes, DNA and other polymers.
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Affiliation(s)
- Hai-Feng Ji
- Institute for Micromanufacturing, Louisiana Tech University, Ruston, LA 71272, USA.
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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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33
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Bergese P, Oliviero G, Alessandri I, Depero LE. Thermodynamics of mechanical transduction of surface confined receptor/ligand reactions. J Colloid Interface Sci 2007; 316:1017-22. [PMID: 17889897 DOI: 10.1016/j.jcis.2007.08.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 08/20/2007] [Accepted: 08/21/2007] [Indexed: 10/22/2022]
Abstract
Chemomechanics of surface stress is discussed in terms of interfacial thermodynamics. In the first section the paper shows how to quantitatively describe the chemical equilibrium of a receptor/ligand binding reaction confined at a solid-liquid interface and how the overall work of the reaction splits into chemical and surface work, that appears as a surface pressure. In the second section this thermodynamic model is applied to describe the experimental results of microcantilever bending induced by DNA hybridization occurring onto one of its faces.
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Affiliation(s)
- Paolo Bergese
- INSTM and Chemistry for Technologies Laboratory, University of Brescia, via Branze 38, 25123 Brescia, Italy.
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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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Wingren C, Borrebaeck CAK. Progress in miniaturization of protein arrays--a step closer to high-density nanoarrays. Drug Discov Today 2007; 12:813-9. [PMID: 17933681 DOI: 10.1016/j.drudis.2007.08.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 08/03/2007] [Accepted: 08/06/2007] [Indexed: 01/22/2023]
Abstract
Protein microarrays is a technology with great promise for high-throughput proteomics. Designing high-performance protein microarrays for global proteome analysis has, however, turned out to be challenging. To this end, major efforts are under way to design novel array formats capable of harboring the tremendous range of probes required to target complex proteomes composed of more than 10000 analytes. By adopting nanotechnology, the first generation of miniaturized nanoarrays has recently emerged, which opens up new avenues for global proteome analysis and disease proteomics. This review describes the progress and key issues in designing miniaturized protein arrays.
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Affiliation(s)
- Christer Wingren
- Department of Immunotechnology, Lund University, BMC D13, SE-221 84 Lund, Sweden.
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Bálint Z, Végh GA, Popescu A, Dima M, Ganea C, Varó G. Direct observation of protein motion during the photochemical reaction cycle of bacteriorhodopsin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:7225-8. [PMID: 17503866 DOI: 10.1021/la700666p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Platinum-coated, conductive atomic force microscope cantilevers were used to deposit electrophoretically purple membranes from Halobacterium salinarum on the bottom part of the cantilevers. By illuminating the bacteriorhodopsin-containing purple membranes, the protein goes through its photochemical reaction cycle, during which a conformational change happens in the protein, changing its shape and size. The size change of the protein acts upon the cantilever by causing its deflection, which can be monitored by the detection system of the atomic force microscope. The shape of the signal, the action spectrum of the deflection amplitude, and the blue light inhibition of the deflection all prove that the origin of the signal is the conformational change arising in the bacteriorhodopsin during the photocycle. From the size of the signal, the magnitude of the protein motion could be estimated. Using polarized light, the orientation of the motion was determined, relative to the transition moment of the retinal.
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Affiliation(s)
- Zoltán Bálint
- Institute of Biophysics, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary H-6726
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Braun T, Ghatkesar MK, Barwich V, Backmann N, Huber F, Grange W, Nugaeva N, Lang HP, Ramseyer JP, Gerber C, Hegner M. Digital processing of multi-mode nano-mechanical cantilever data. ACTA ACUST UNITED AC 2007. [DOI: 10.1088/1742-6596/61/1/069] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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38
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Shu W, Laue ED, Seshia AA. Investigation of biotin–streptavidin binding interactions using microcantilever sensors. Biosens Bioelectron 2007; 22:2003-9. [PMID: 17045792 DOI: 10.1016/j.bios.2006.08.047] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 08/15/2006] [Accepted: 08/25/2006] [Indexed: 11/18/2022]
Abstract
We report the investigation of biotin-streptavidin binding interactions using microcantilever sensors. A symmetric cantilever construction is employed to minimize the effects of thermal drift and the control of surface chemistry on the backside of the cantilever is demonstrated to reduce the effects of non-specific binding interactions on the cantilever. Three structurally different biotin modified cantilever surfaces are used as a model system to study the binding interaction with streptavidin. The cantilever response to the binding of streptavidin on these biotin sensing monolayers is compared. The lowest detection limit of streptavidin using biotin-HPDP is found to be between 1 and 10nM limited by the optical measurement setup. Surface characterization using quartz crystal microbalance (QCM) and high-resolution atomic force microscope (AFM) is used to benchmark the cantilever sensor response. In addition, the QCM and AFM studies reveal that the surface density of bound streptavidin on biotin modified surfaces was low, thereby implying that effects other than steric hindrance are responsible for defining cantilever response.
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Affiliation(s)
- Wenmiao Shu
- The Nanoscience Centre, University of Cambridge, 11 J.J. Thomson Avenue, Cambridge CB3 0FF, UK
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39
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Hammiche A, Walsh MJ, Pollock HM, Martin-Hirsch PL, Martin FL. Non-contact micro-cantilevers detect photothermally induced vibrations that can segregate different categories of exfoliative cervical cytology. ACTA ACUST UNITED AC 2007; 70:675-7. [PMID: 17320188 DOI: 10.1016/j.jbbm.2007.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2006] [Accepted: 01/21/2007] [Indexed: 11/29/2022]
Abstract
We implemented a non-contact photo-thermo-mechanical recording method whereby a silicon nitride atomic force microscopy cantilever is placed several micrometer above the surface of samples. Samples were illuminated with infrared (IR) radiation after which, cantilever mechanical vibrations were optically sensed. Following spectrometric acquisition and Fourier transformation, true IR absorption spectra were obtained. With multivariate analysis, segregation between different categories of exfoliative cervical cytology was obtained. This approach points towards the implementation of a novel near-field system that allows IR spectral analysis without probe contamination.
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40
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Pera I, Fritz J. Sensing lipid bilayer formation and expansion with a microfabricated cantilever array. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:1543-7. [PMID: 17241085 DOI: 10.1021/la0624337] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We show that cantilever array sensors can sense the formation of supported phospholipid bilayers on their surface and that they can monitor changes in mechanical properties of lipid bilayers. Supported lipid bilayers were formed on top of microfabricated cantilevers by vesicle fusion. The formation of bilayers led to a bending of the cantilevers of 70-590 nm comparable to a surface stress of 27-224 mN/m. Physisorption of bilayers of DOPC and other bilayers on the silicon oxide surface of cantilevers led to a tensile bending of about 70 nm whereas formation of chemisorbed bilayers of mixed thiolated (DPPTE) and non-thiolated lipids (DOPC) on the gold side of cantilevers led to a compressive bending of nearly 600 nm which depended on the ratio of DPPTE to DOPC. First results on bending of bilayer-covered cantilevers due to their interaction with the pore-forming peptide melittin are shown. The results demonstrate that cantilever sensors with immobilized bilayers can be used as model systems to investigate mechanical properties of cellular membranes and may be used for screening of membrane processes involving modification, lateral expansion, or contraction of membranes.
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Affiliation(s)
- Ioana Pera
- School of Engineering and Science, International University Bremen, Campus Ring 1, 28759 Bremen, Germany
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