Fabricated nanogap-rich plasmonic nanostructures through an optothermal surface bubble in a droplet

Karim, Farzia; Vasquez, Erick S.; Zhao, Chenglong

doi:10.1364/ol.43.000334

Cited by 16 publications

(21 citation statements)

References 25 publications

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“…It is mentioned in section 4.1 of this chapter that, gold coating on glass coverslip is not a pre-requirement for generatiing an OGMB. It is also reported in one of our publications 22 that, OGMB can be also generated on a glass coverslip without gold coating. In order to prove this statement, we have generated an OGMB on a glass coverslip without gold coating.…”

Section: Effect Of Gold-coating On Substrate For Nanogap-rich Structusupporting

confidence: 54%

“…Effect of gold film for the generation of OGMB is reported in one of our publications in Optics Letters. 22 For OGMB generation through laser heating, at first one droplet of nanoparticles (gold nanoshells) solution was placed on a glass coverslip substrate. Fiber tip was then immersed into the droplet of gold nanoshells solution.…”

Section: Limitation Of Active Sensing Methods For Biosensing Applicationmentioning

confidence: 99%

“…3 shows the working principle of OGMB-based active sensing as follows: Flowchart of OGMB-based fabrication of nanogap-rich structure and active analytes sensing 22,23. 1) At first a droplet of metallic nanoparticles solution is placed on a cover glass coated with 10 nm thick gold film.…”

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confidence: 99%

“…2 (a) Schematic of experimental setup for optothermal microbubble generation 22. L: lens; BS: beam splitter; DM: dichroic mirror; O: objective lens; TL: tube lens; CCD: charge coupled device; ND: variable neutral density filter; PM: power meter.…”

mentioning

confidence: 99%

“…Optical image of a nanoliter droplet of gold nanosphere solution (a) before and (b) after generation of an optothermal microbubble inside the droplet of gold nanosphere 22. (c) a nanoliter injector known as 'Nanoliter 2010' which was used to create nanoliter droplet of gold nanosphere.The focused laser beam increases the local temperature of the gold-coated glass substrate and therefore an OGMB is generated inside the droplet of gold nanosphere accociated with a strong Marangoni convective flow around the OGMB.…”

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confidence: 99%

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Active and Ultrasensitive Chemical and Biosensing through Optothermally Generated Microbubble

Karim

Sun

Vasquez

et al. 2020

Conference on Lasers and Electro-Optics

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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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Section: Effect Of Gold-coating On Substrate For Nanogap-rich Structusupporting

confidence: 54%

Section: Limitation Of Active Sensing Methods For Biosensing Applicationmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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