Magnetoplasmonics Lab

Archives July 2024

Congratulations for Our New Paper in Journal of Measurment

Detection of gentamicin in water and milk using chitosan-ZnS-Au nanocomposite based on surface plasmon resonance imaging sensor
Amir Reza Sadrolhosseini, Seyedeh Mehri Hamidi⁎, Younes Mazhdi

The detection of antibiotics in milk, water, and agricultural products is a topic of interest for health care and environmental protection. Some antibiotics such as oxytetracycline and gentamicin are the prominent contaminants in water and milk. In this study, the chitosan-ZnS and chitosan-ZnS-Au nanocomposites were fabricated using a laser ablation technique. The nanocomposites were covered on the glass substrate as a layer sensor characterized by analytical methods. Consequently, the thickness of layers was in the range of 36.3 to 38.21 nm. The surface plasmon resonance image patterns demonstrated the interaction of the gentamicin and oxytetracycline with nanocomposites. As a result, the sensor is sensitive to detect gentamicin, and the limit of detection, the affinity constant, and response time were about 0.1 ppm, 102.04 a.u., and 268 s respectively.

PhD Congratulations

Many Congratulations to Dr. Meisam Haghparast for achieving PHD degree! Many congratulations on your success. You’ve inspired all of us not only to dream but also to work hard to achieve them. Wish you many years of achievement of your goal and success.

Congratulations for our new paper in Journal of Magnetism and Magnetic Materials

Development of a novel four-channel atomic gradiometric magnetometer
for magnetocardiography: Advancing non-invasive cardiac research with
enhanced sensitivity and spatial resolution
M. Ranjbaran, R. Sedeyan, A. Zamani, M.M. Tehranchi, S.M.H. Khalkhali, S.
M. Hamidi

The field of magnetocardiography (MCG) has witnessed significant advancements with the use of atomic mag- netometers (AMs) and gradiometers, offering numerous advantages over traditional superconducting quantum interference devices (SQUIDs). This study focuses on the development of a highly sensitive four-channel atomic gradiometer specifically designed for measuring the biomagnetic fields of a rat’s heart. By utilizing gradiometric detection and monitoring deviations in the Larmor frequency of rubidium (Rb) atoms, this gradiometer captures cardiac signals with exceptional sensitivity and spatial resolution. One of the key challeng hies in utilizing AMs as gradiometers lies in minimizing cross-talk effects among the sensors to ensure accurate measurements. In this study, we successfully address this challenge, leading to precise and reliable data acquisition. Furthermore, our gradiometer demonstrates a linear response across a wide range of frequencies, enhancing its versatility and applicability in various experimental setups. The achieved sensitivity of 350 fT/√Hz by our atomic gradiometer showcases its potential in assessing MCG measurements for studying cardiac electrical activities. The non- invasive nature of the technique, combined with the elimination of cryogenic cooling requirements, opens up new avenues for cardiac research and diagnostics. The enhanced spatial and spatiotemporal resolution offered by optically pumped magnetometers (OPMs) further enhances our ability to understand and analyze complex cardiac phenomena.

News On Frequency Stabilization

In these days, the Journal of Photonics published a new paper entitled as “Simplified 1.5 μm Distributed Feedback Semiconductor Laser (DFB-LD) Frequency Stabilization System Based on Gas Absorption Chamber”

Abstract: The classical 1.5 μm band frequency-stabilized laser using acetylene gas saturated absorption can achieve high frequency stability and reproducibility, but its system design is complex and bulky. For some practical applications, a simple, compact system containing anti-interference abilities is preferred. In this study, a low-cost and simple-structured 1.5 μm frequency-stabilized laser is constructed using digital control methods, wavelength modulation technology, and acetylene gas absorption. The fiber input and output optical devices of the system significantly simplify the optical path and reduce the volume of the system. The error signal is obtained by the first-order differential method, and a combination of the high-speed comparator circuit and the microcontroller unit (MCU) is used to detect the error signal. Through the feedback control method of coarse temperature adjustment and fine current adjustment, the second-level frequency stability of the laser is stabilized within 100 kHz, that is, the frequency stability reaches 10−10. The designed system achieved continuous and stable operation for more than 6 h, and the long-term frequency stability reached 10−9.

📣Congratulations on our new Patent😍

خانم دکتر سیده مهری حمیدی، استاد و همراه عزیز، از درگاه ایزد منان مزید توفیقات شما و همکارانتان را برای خدمتی سرشار از شور و نشاط و مملو از توکل الهی در جهت رشد و شکوفایی ایران اسلامی مسئلت داریم.

News On Thermo-plasmonics

In these days, the Journal of Nano Letters published a new paper entitled as “Biological Applications of Thermoplasmonics”

ABSTRACT: Thermoplasmonics has emerged as an extraordinarily versatile tool with profound applications across various biological domains ranging from medical science to cell biology and biophysics. The key feature of nanoscale plasmonic heating involves remote activation of heating by applying laser irradiation to plasmonic nanostructures that are designed to optimally convert light into heat. This unique capability paves the way for a diverse array of applications, facilitating the exploration of critical biological processes such as cell differentiation, repair, signaling, and protein functionality, and the advancement of biosensing techniques. Of particular significance is the rapid heat cycling that can be achieved through thermoplasmonics, which has ushered in remarkable technical innovations such as accelerated amplification of DNA through quantitative reverse transcription polymerase chain reaction. Finally, medical applications of photothermal therapy have recently completed clinical trials with remarkable results in prostate cancer, which will inevitably lead to the implementation of photothermal therapy for a number of diseases in the future. Within this review, we offer a survey of the latest advancements in the burgeoning field of thermoplasmonics, with a keen emphasis on its transformative applications within the realm of biosciences.