arXiv subjects

Nageswar Reddy Sanamreddy

Publications and source records attributed to Nageswar Reddy Sanamreddy.

3 recordsLinked to original sources

arXiv2026

Magnetoplasmonic Nanopore Lensing for Enhanced Optical Readout and Controlled Translocation

Plasmonic nanopores hold a significant promise for molecular sequencing, but their sensitivity and temporal resolution are constrained by limited signal strength and rapid translocation of molecules through the pore. Here we report an experimentally developed hybrid magnetoplasmonic nanopore platform based on bull's-eye geometry that concentrates surface plasmon polaritons into the pore, resulting in significant electric-field enhancement and improved signal readout. The addition of a ferromagnetic layer allows for magnetic tweezing of magneto-plasmonic nanoparticle-tagged molecules, providing active control over their translocation dynamics. Simulations reveal a further boost in enhancement arising from mirror-on-mirror plasmonic coupling between the nanopore and wall-aligned tagged nanoparticles. Together, experimental realization and simulation-guided insights establish a magnetically configurable, plasmonically enhanced nanopore platform that combines signal amplification with controlled translocation for advanced single-molecule sensing and sequencing. KEYWORDS: Nanopores, plasmonics, single-molecule sequencing, magneto-plasmonics, active control, magnetic tweezing.

physics.optics↗

arXiv2026

Reconfigurable Magnetic Nanopore Platform for Selective Trapping

Solid-state nanopores offer a powerful platform for nanoscale analysis of individual analytes, including biomolecules and functionalized nanoparticles, by confining them within a precisely defined sensing region. However, their inherently passive operation restricts practical applications, as they cannot precisely control particle position or dynamics inside the pore. Here, we introduce magnetic nanopore architectures that integrate a ferromagnetic layer into the nanopore system. Acting as a magnetic discontinuity within an otherwise uniformly magnetized film, the nanopore generates localized stray magnetic fields that enable magnetic tweezing of magnetic nanoparticles, which can be functionalized with fluorescent biomolecules. Importantly, the nanopore geometry is designed to reversibly switch between a nearly uniform magnetization state and a magnetic flux-closure state through the application of short magnetic field pulses of controlled amplitude. This capability allows the magnetic tweezing effect to be selectively activated or deactivated, enabling controlled capture and release of tagged biomolecules on demand. As a proof of concept, we demonstrate the selective magnetic trapping of fluorescent magnetic particles. These findings pave the way for reconfigurable, on-chip magnetic nanopore platforms capable of selective trapping and high-throughput single-particle detection. KEYWORDS: Nanopores, magnetic tweezers, fluorescence microscopy, vortex state, active control, magnetic nanoparticles

physics.optics↗

arXiv2025

Plasmonic Janus particles: A perspective on optical manipulation and biomedical applications

The compositional asymmetry of Janus micro- and nanoparticles gives unprecedented opportunities to manipulate such composite particles with different stimuli to achieve enhanced optical, magnetic and photothermal responses, which can be exploited for sensing, phototherapy, and nanoscale robotic applications. This perspective overviews recent advances in optical manipulation of plasmonic Janus particles and their implications for biomedical applications. In particular, a brief summary of optical, plasmonic, and magnetic manipulation of Janus particles of various compositions are presented. Moreover, the potentials of plasmonic and magnetic Janus particles for targeted drug delivery, photothermal therapy, hyperthermia, bio-imaging, bio-detection, and neuromodulation are briefly discussed. Finally, a perspective on the rational design and applications of this particular family of asymmetric particles is forwarded.

physics.optics↗