Review of optical detection of single molecules beyond the diffraction and diffusion limit using plasmonic nanostructures

Karim, Farzia; Smith, T. B.; Zhao, Chenglong

doi:10.1117/1.jnp.12.012504

“…Single-molecule fluorescence [1][2][3][4][5][6][7] has been successfully applied to many areas of biomedicine, including DNA sequencing, 8,9 diagnostics, 10 and molecular biology. 11 In particular, in the field of next generation sequencing (NGS), single molecule fluorescence detection is the technique at the core of commercially available devices.…”

Section: Introductionmentioning

confidence: 99%

Plasmonic zero mode waveguide for highly confined and enhanced fluorescence emission

Ponzellini

¹

,

Zambrana‐Puyalto

²

,

Maccaferri

³

et al. 2018

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We fabricate a plasmonic nanoslot that is capable of performing enhanced single molecule detection at 10 μM concentrations. The nanoslot combines the tiny detection volume of a zero-mode waveguide and the field enhancement of a plasmonic nanohole. The nanoslot is fabricated on a bi-metallic film formed by the sequential deposition of gold and aluminum on a transparent substrate. Simulations of the structure yield an average near-field intensity enhancement of two orders of magnitude at its resonant frequency. Experimentally, we measure the fluorescence stemming from the nanoslot and compare it with that of a standard aluminum zero-mode waveguide. We also compare the detection volume for both structures. We observe that while both structures have a similar detection volume, the nanoslot yields a 25-fold fluorescence enhancement.

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“…In the past 30 years, considerable efforts have been successfully devoted to best detect single photons emitted by discrete sub-wavelength size objects such as single molecules, or to localize such point-like emitters when sparsely distributed over an object field. This has led to a huge diversity of methods aimed at single photon detection and imaging [1][2][3][4][5] .…”

Section: Detectivity Optimization To Detect Of Ultraweak Light Fluxesmentioning

confidence: 99%

Detectivity optimization to measure ultraweak light fluxes using an EM-CCD as binary photon counter array

Khaoua

¹

,

Graciani

²

,

Kim

³

et al. 2021

Sci Rep

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For a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

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“…However, it fails to work efficiently at a highly diluted solution because it takes unrealistically long times to diffuse towards the small sensing area of the sensor. [29][30][31][32] For example, the detecion limitation of a practical passive sensing is at picomolar-range for a nanoscale sensor. 27 Figure 2.1 Schematic of (a) passive sensing method (b) active sensing method.…”

Section: Passive Sensing Methodsmentioning

confidence: 99%

Active and Ultrasensitive Chemical and Biosensing through Optothermally Generated Microbubble

Karim

¹

,

Sun

²

,

Vasquez

³

et al. 2020

Conference on Lasers and Electro-Optics

Self Cite

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Rapid and sensitive detection of harmful chemicals or biological samples is essential for medical study and industrial applications. For example, in the food industry, it is an urgent demand to detect hazardous chemicals or pathogens and then efficiently eliminate contaminated sources from the food production chain to protect people from toxic food-borne infection. In addition, toxic chemicals, pesticides and pathogens are also responsible for water, air and soil contamination. Therefore, rapid and sensitive detection of toxic chemicals or pathogens are very important to ensure food safety and evaluating environmental pollution. Most of the sensing systems for detecting chemical or biological samples apply a passive sensing method, in which binding of analytes to the sensor happens through free diffusion. Due to this free diffusion of analytes in a passive sensing method, diffusing process takes several hours even days, especially when the analytes are at low concentrations and therefore suffer from so called diffusion limit. A higher sensitivity can be achieved in passive sensing methods, with nanoscale sensors but at a cost of reduced speed and vice versa. Therefore, speed and sensitivity of sensing need to be traded off. Active sensing methods, in which analytes are actively concentrated towards the sensor, can be used to break the diffusion limit of sensing and significantly improve the sensitivity. In this work, an ultrasensitive and cost-effective chemical and biosensing platform has been developed under ambient condition to demonstrate active sensing of analytes. This method v works based on an optothermally generated microbubble (OGMB). OGMB is a micronsized bubble that is generated on a liquid-solid interface through laser heating. Due to the strong convective flow induced by OGMB, nanoparticles or analytes can be attracted towards the OGMB and deposited on the surface of a substrate. We have successfully fabricated nanogap-rich structures by generating an OGMB on a glass substrate. The nanoparticles in the nanogap-rich structures form many nanogaps that are ideal for surface enhance Raman scattering (SERS) due to the plasmonic resonance of nanogap-rich structures. Analytes for example any chemical or biological samples can be actively concentrated on the nanogap-rich structure for SERS detection. The OGMB-assisted active sensing method can improve the detection limit of analytes by an order of magnitude compared to that with a passive sensing and thus overcome the diffusion limit of conventional passive sensing methods. Therefore, we expect that, OGMB-assisted active sensing method will find potential applications in advanced chemical and bio-sensing. DEDICATION vi Dedicated to my mother who is my pride, inspiration, strength and my life. vii ACKNOWLEDGMENTS At the beginning, all the praise to Almighty for giving me the capability for successful completion of this work. I would like to express my sincere indebtedness to all who have given me the chance to finish this research. Without their generous sup...

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Review of optical detection of single molecules beyond the diffraction and diffusion limit using plasmonic nanostructures

Cited by 13 publications

References 103 publications

Plasmonic zero mode waveguide for highly confined and enhanced fluorescence emission

Plasmonic zero mode waveguide for highly confined and enhanced fluorescence emission

Detectivity optimization to measure ultraweak light fluxes using an EM-CCD as binary photon counter array

Active and Ultrasensitive Chemical and Biosensing through Optothermally Generated Microbubble

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