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Integration of plasmonic heating and ona??chip temperature sensor for nucleic acid amplification assays
摘要： Nucleic acid tests have been widely used for diagnosis of diseases by detecting the relevant genetic markers that are usually amplified using polymerase chain reaction (PCR). This work reports the use of a plasmonic device as an efficient and low-cost PCR thermocycler to facilitate nucleic acid-based diagnosis. The thermoplasmonic device, consisting of a one-dimensional metal grating, exploited the strong light absorption of plasmonic resonance modes to heat up PCR reagents using a near-infrared laser source. The plasmonic device also integrated a thin-film thermocouple on the metal grating to monitor the sample temperature. The plasmonic thermocycler is capable of performing a PCR amplification cycle in approximately 2.5 minutes. We successfully demonstrated the multiplex and real-time PCR amplifications of the antibiotic resistance genes using the genomic DNAs extracted from Acinetobacter baumannii, Klebsiella pneumonia, Escherichia coli, and Campylobacter.
关键词： polymer chain reaction,thermoplasmonics,thermocycler,nucleic acid-based diagnostics,antibiotic resistance detection,Photothermal effect
更新于2025-09-23 15:19:57
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Theoretical Analysis of Metallic-Nanodimer Thermoplasmonics for Phototactic Nanoswimmers
摘要： We assess the potentiality of several geometries of metallic nanodimers (one of the simplest thermoplasmonic systems) as candidates for active particles (nanoswimmers) propelled and controlled by light (phototaxis). The studied nanodimers are formed by two spherical nanoparticles of gold, silver, or copper with radii ranging from 20 to 100 nm. Contrary to most proposals, which assume the asymmetry of the systems as a requirement for self-propulsion, our results show that nanodimers made of identical nanoparticles are excellent candidates for phototactic self-thermophoretic systems. Nonsymmetrical nanodimers, although having a tunable effective diffusion, possess much lower or negligible average thermophoretic forces. We show that the effective diffusion and the net thermophoretic force in both types of systems depend strongly on the wavelength of the incident light, which makes these properties highly tunable. Our study may be useful for the design of simple-to-make but controllable self-propelled nanoparticles. This can find numerous applications ranging from autonomous drug-carrying to controlling the self-assembly of complex nanomaterials.
关键词： nanoswimmers,phototaxis,thermoplasmonics,thermophoresis,active matter,nanodimer,self-propelled particles
更新于2025-09-23 15:19:57
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Thermoplasmonic Maskless Lithography on Upconverting Nanocomposites Assisted by Gold Nanostars
摘要： Photothermal effects in plasmonic nanoparticles can be used to locally modify temperature-sensitive materials. Polylactic acid (PLA) is a thermoplastic biodegradable polymer with a glass transition temperature around 60 ?C that has been popularized as a feedstock material for 3D printing. Here, we extend its use to produce thin PLA films that can be modified at the microscopic level when covered with gold nanostars (AuNSs). The heat dissipation generated when exciting the plasmon resonance of AuNSs, under exposure to 976 nm focused laser light, produce an increase in the local temperature of more than 100 ?C. When the temperature surpasses the glass transition of the base PLA layer, AuNSs get attached to the polymer surface. The following dissolution of the unexposed material in acetone bath permits the precise control of the engraving process at the microscale. Furthermore, Er3+ doped upconverting nanoparticles embedded into the PLA layer can act as optical nanothermometers to probe the local temperature, simultaneously allowing the visualization of the laser spot. A computer numerical control (CNC) system was developed to drive the laser writing beam and transfer 2D patterns, opening up the thermoplasmonic maskless lithography technique. Suitable for rigid and flexible substrates coated with PLA, the methods and materials developed here were applied to produce patterned substrates for surface enhanced Raman spectroscopy, and luminescent optical encoding for anti-counterfeiting technologies.
关键词： photothermal nanoparticles,gold nanostars,optical thermometry,thermoplasmonics,maskless lithography,upconversion nanoparticles
更新于2025-09-16 10:30:52
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Ultrafast Modulation of Thermoplasmonic Nano-Bubbles in Water.
摘要： Thermo-optically generated bubbles in water provide a powerful means for active matter control in microfluidic environments. These bubbles are often formed via continuous-wave illumination of an absorbing medium resulting in bubble nucleation via vaporization of water and subsequent bubble growth from the inward diffusion of gas molecules. However, to date such bubbles tend to be several microns in diameter, resulting in slow dissipation. This limits the dynamic rate, spatial precision and throughput of operation in any application. Here we show that isolated plasmonic structures can be utilized as highly localized heating elements to generate thermoplasmonic nanobubbles that can be modulated at frequencies up to several kilohertz in water, orders of magnitude faster than previously demonstrated for microbubbles. The nanobubbles are envisioned as advantageous localized active manipulation elements for high throughput microfluidic applications.
关键词： thermoplasmonic bubbles,nanobubbles,thermoplasmonic phase change,bubble nucleation,thermoplasmonics
更新于2025-09-11 14:15:04