Article
Chemistry, Multidisciplinary
Kosti Tapio, Amr Mostafa, Yuya Kanehira, Antonio Suma, Anushree Dutta, Ilko Bald
Summary: DNA origami technology enables precise assembly of chemical entities at the nanoscale, creating sophisticated functional materials. By assembling Au or Ag nanoparticle dimers, a versatile DNA origami nanofork antenna (DONA) has been developed, achieving signal enhancements in surface-enhanced Raman scattering (SERS) up to 10(11). Using the DNA origami structure, single-molecule SERS measurements of three dyes, cytochrome c, and horseradish peroxidase proteins have been successfully demonstrated.
Article
Nanoscience & Nanotechnology
Yanlin Mi, Yinzhou Yan, Mengyuan Wang, Lixue Yang, Jing He, Yijian Jiang
Summary: Researchers have reported a novel hybrid SERS substrate composed of a large microsphere and a small microsphere array with Ag nanoparticles. The cascaded structure allows for increased molecular concentration, enhanced intensity of excitation light, and giant Raman enhancement.
Article
Materials Science, Multidisciplinary
Kishan S. Menghrajani, Mingzhou Chen, Kishan Dholakia, William L. Barnes
Summary: Raman spectroscopy is a powerful technique for fingerprinting materials and molecules, but fluorescence interference is a common issue. Wavelength-modulated Raman spectroscopy can reduce fluorescence background, allowing clear recording of desired Raman signals. While studying vibrational strong coupling, advantages of the wavelength-modulated Raman approach are found, but results on strong coupling remain inconclusive, calling for further research.
ADVANCED OPTICAL MATERIALS
(2022)
Review
Chemistry, Multidisciplinary
Wenjing Liu, You-Ling Chen, Shui-Jing Tang, Frank Vollmer, Yun-Feng Xiao
Summary: Optical microresonators have been widely studied for highly sensitive molecular detection and optical precision measurement. The combination of high quality factor and small mode volume in whispering-gallery mode microresonators enhances nonlinear light-matter interaction, enabling label-free molecule detection with ultrahigh sensitivity and specific spectral fingerprinting of molecules. These nonlinear optical sensors show promise for future research and applications in sensing technologies.
Article
Chemistry, Multidisciplinary
Debadrita Paria, Kam Sang Kwok, Piyush Raj, Peng Zheng, David H. Gracias, Ishan Barman
Summary: The study reports a large-scale and label-free testing platform that combines surface-enhanced Raman spectroscopy and machine learning for rapid and accurate detection of SARS-CoV-2. The technique can not only distinguish between different types of viruses, but also detect virus signatures in human saliva without additional sample preparation.
Article
Chemistry, Analytical
Abeer Al Ghamdi, Benjamin Dawson, Gin Jose, Almut Beige
Summary: One way to monitor molecule concentrations optically is to utilize the high sensitivity of the transmission and reflection rates of Fabry-Perot cavities to changes in their optical properties. Fabry-Perot cavities can be used to non-invasively and remotely monitor molecule concentrations by reflecting light from the target molecules back into the cavity, which adds peaks to the overall reflection rate. An array of optical cavities can be used to probe a wide range of frequencies and obtain a unique optical fingerprint.
Review
Engineering, Electrical & Electronic
Flavio Esposito, Anubhav Srivastava, Lucia Sansone, Michele Giordano, Stefania Campopiano, Agostino Iadicicco
Summary: This paper presents a comprehensive review of the design, development, and testing of label-free biosensors based on in-fiber long period gratings. It focuses on optical transducers and methodologies that enhance sensitivity, as well as coating nanomaterials, bio-functionalization strategies, and recognition elements for selectivity. The aim is to provide an overview of the current state of LPG-based label-free biosensors and highlight future research trends.
IEEE SENSORS JOURNAL
(2021)
Article
Nanoscience & Nanotechnology
Alfredo Franco, Veronica Vidal, Marcos Gomez, Olga Gutierrez, Maria Martino, Francisco Gonzalez, Fernando Moreno, Jose L. Fernandez-Luna
Summary: The study introduces a system using a gold nanohole array biosensor and microscope optical design to discriminate between live cancer cells and normal cells. Differences in spectral behavior between tumor and non-tumor cells are influenced by the actin cortex within the short penetration depth of the surface plasmon electromagnetic field. The system shows high discrimination capacity between normal and colorectal cancer cells, with sensitivity and specificity values ranging between 80-100% and 87-100%, respectively.
Article
Engineering, Electrical & Electronic
Mohammadreza Salehi Moghaddam, Hamid Latifi, Elham Abedini, Mohsen Ghazanfar, Ebrahim Behroodi, Mojde Salmani Sadeghi
Summary: The optical pH sensor based on smart hydrogel material was designed for microfluidic applications. The sensor made use of chitosan-TEOS interpenetrating network as a pH-sensitive component. By bonding the chitosan-TEOS-PDMS layer to a thin layer of PDMS, the sensor can be easily integrated into microfluidic chips. The thickness of the PDMS layer can be adjusted to control the sensitivity of the sensor. The sensor's response to pH changes was measured using the optical astigmatism method, and the experimental results showed its stability and sensitivity.
IEEE SENSORS JOURNAL
(2023)
Article
Biophysics
Jiri Slaby, Jiri Homola
Summary: In this study, we analyze the performance of label-free optical biosensors in detecting analyte-induced refractive index changes. We propose an analytical model that relates the refractive index resolution to the parameters of the optical platform. Our findings demonstrate that the widely used figure of merit (FOM) is not suitable for guiding the design or predicting the performance of label-free optical biosensors. Therefore, we propose an extended definition of FOM to address its limitations. The validity of our approach is confirmed through numerical simulations and experiments, and we show that the analytical model not only predicts the performance of biosensors but also provides strategies for achieving optimal performance.
BIOSENSORS & BIOELECTRONICS
(2022)
Article
Materials Science, Multidisciplinary
Rahul Prajesh, Rakesh Kumar Saini, Ashok Kumar Sharma, Ajay Agarwal
Summary: Thiram is a fungicide with health-related issues when consumed regularly. Monitoring its presence in food and vegetables is crucial. This study aims to develop a low-cost and simple label-free SERS active substrate for detecting low-level concentrations of Thiram.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Yaoran Liu, Zilong Wu, Pavana Siddhartha Kollipara, Richard Montellano, Kumar Sharma, Yuebing Zheng
Summary: The study demonstrated label-free detection of chiral molecules with microbubble-induced rapid accumulation on plasmonic chiral sensors, achieving ultra-high sensitivity and low sample consumption. This method has potential for clinical applications in detecting abnormal chirality in biofluids related to diabetes.
Article
Engineering, Electrical & Electronic
Chenxu Lu, Xiaopeng Dong, Chi Wu
Summary: This article proposes a novel detection scheme that measures temperature through the detection of a unique and easily identifiable critical wavelength (CWL) in a modified Vernier envelope. The Vernier envelope is created by cascading two existing single-mode fiber (SMF)-few-mode fiber (FMF)-SMF (SFS) structures with a varying free spectrum range (FSR) at the CWL. Experimental and simulation results show that the CWL in the Vernier envelope shifts monotonically with temperature, and the sensitivity is improved compared to a single SFS structure.
IEEE SENSORS JOURNAL
(2023)
Article
Nanoscience & Nanotechnology
Ying Zhu, Peter J. Reece
Summary: This study introduces a phase-based imaging approach using differential interference contrast (DIC) as a means of label-free optical sensing with plasmonic nanohole arrays. By developing a colorimetric-based imaging readout and evaluating the refractive-index sensing capability using a layer-by-layer polyelectrolyte deposition model, the researchers cross-validate the DIC imaging approach and show good agreement among different measurements, opening up potential applications for rapid and multiplexed sensing using the phase response of nanoplasmonic structures.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Lixing Kang, Yan Zhang, Qian Gong, Chandreyee Manas Das, Huilin Shao, Daniel Puiu Poenar, Philippe Coquet, Ken-Tye Yong
Summary: This study presents the fabrication, testing, and performance of a plasmonic sensor using a gold nanohole array chip coated with WS2 for protein-protein interaction detection. The monoatomic layer deposition of WS2 and its functionalization significantly improved the sensor's performance, enhancing the limit of detection.
Review
Chemistry, Multidisciplinary
Wenjing Liu, You-Ling Chen, Shui-Jing Tang, Frank Vollmer, Yun-Feng Xiao
Summary: Optical microresonators have been widely studied for highly sensitive molecular detection and optical precision measurement. The combination of high quality factor and small mode volume in whispering-gallery mode microresonators enhances nonlinear light-matter interaction, enabling label-free molecule detection with ultrahigh sensitivity and specific spectral fingerprinting of molecules. These nonlinear optical sensors show promise for future research and applications in sensing technologies.
Review
Optics
Nikita Toropov, Gema Cabello, Mariana P. Serrano, Rithvik R. Gutha, Matias Rafti, Frank Vollmer
Summary: This review discusses the recent advances in biosensing using microlasers based on whispering-gallery modes (WGMs). These miniature lasers have been successfully applied in label-free detection of single virus particles and live-cell tagging and tracking, showing promising potential in the field of biological sensing.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Review
Nanoscience & Nanotechnology
Jolly Xavier, Deshui Yu, Callum Jones, Ekaterina Zossimova, Frank Vollmer
Summary: Quantum-enhanced sensing and metrology offer promising pathways to meet the current demands for integrated chips by utilizing quantum optical measurement schemes for precise measurements of optical properties. These non-classical measurement techniques, based on phenomena like entanglement and squeezing of optical probe states, can also revolutionize biosensing applications and pave the way for integrated quantum optical bioscience laboratories.
Review
Optics
Aneeth Kakkanattu, Narima Eerqing, Shahin Ghamari, Frank Vollmer
Summary: Chiral molecules play an important role in nature, and optical approaches have emerged as effective methods for detecting and manipulating them. Plasmonics has been utilized to enhance the chiroptical response, and dynamic chiral plasmonic nanosystems have been fabricated and assembled for this purpose.
Article
Nanoscience & Nanotechnology
Narima Eerqing, Sivaraman Subramanian, Jesus Rubio, Tobias Lutz, Hsin-Yu Wu, Janet Anders, Christian Soeller, Frank Vollmer
Summary: This study compares the applications of two photonic techniques, fluorescence nanoscopy and optoplasmonic sensing, in single-molecule sensing. By examining the measured single-molecule kinetics, the influence of fluorescent labels and different sensing geometries was investigated. The results demonstrate that DNA dissociation is affected by geometric factors, while DNA association is not significantly altered by fluorescent labels.
Review
Chemistry, Multidisciplinary
Nikita Toropov, Eleanor Osborne, Lovleen Tina Joshi, James Davidson, Caitlin Morgan, Joseph Page, Justin Pepperell, Frank Vollmer
Summary: This review discusses emerging biosensors for SARS-CoV-2 detection and current biochemical and clinical assays used in hospitals and clinical laboratories. It explores the gap between current testing practices in laboratories and nucleic acid amplification methods, as well as the robustness sought by laboratories. Additionally, it reviews emerging technology and antibody tests to evaluate vaccine effectiveness in individuals.
Article
Chemistry, Multidisciplinary
Keisuke Watanabe, Hsin-Yu Wu, Jolly Xavier, Lovleen Tina Joshi, Frank Vollmer
Summary: On-chip silicon microcavity sensors have advantages in virus and biomolecule detection due to their compactness and enhanced light-matter interaction. This study proposes and demonstrates label-free single virus detection using silicon photonic crystal random cavities. The method does not require pre-fabricated defect cavities or optical couplers.
Article
Physics, Multidisciplinary
Deshui Yu, Frank Vollmer
Summary: Explored the general characteristics of active optomechanics, including the effects of mechanical oscillation on laser dynamics and the quantum interactions between photons and phonons.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Multidisciplinary
Hsin-Yu Wu, Frank Vollmer
Summary: By utilizing an achiral optical system obeying parity-time symmetry, coherent perfect absorption is predicted to significantly enhance the detection of molecular chirality, increasing the sensitivity to weak chiral signals by three orders of magnitude and allowing for accurate measurement of chiroptical parameters.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Multidisciplinary
Hsin-Yu Wu, Frank Vollmer
Summary: This study demonstrates a method for amplifying chiroptical responses using magnetoelectric nanoparticles capped with an optically active monolayer to eliminate background interference. By simultaneously exciting magnetic and electric modes, the magnetoelectric coupling is enhanced, resulting in improved chiroptical responses from the nanoparticles.
COMMUNICATIONS PHYSICS
(2023)
Article
Chemistry, Physical
Narima Eerqing, Hsin-Yu Wu, Sivaraman Subramanian, Serge Vincent, Frank Vollmer
Summary: This study developed an integrated optical setup that combines optoplasmonic and DNA-PAINT techniques for detecting oligonucleotides. The experimental results of both techniques were compared and complementary insights into single molecule processes were provided. Hybridisation events were observed in the same sample cell using fluorescence and optoplasmonic sensor signals, revealing the accumulation of irreversible hybridisation events in optoplasmonic sensing and the novel physicochemical mechanisms that stabilize DNA hybridisation on optically-excited plasmonic nanoparticles.
NANOSCALE HORIZONS
(2023)
Article
Nanoscience & Nanotechnology
Sivaraman Subramanian, Hannah B. L. Jones, Simona Frustaci, Samuel Winter, Marc W. van der Kamp, Vickery L. Arcus, Christopher R. Pudney, Frank Vollmer
Summary: This paper presents a label-free gold nanoparticle-based single-molecule optical platform for studying single enzymes. The experimental results show that this method can accurately track enzyme turnover as a function of conformational changes, providing insights into the relationship between enzyme activity and thermodynamics. Additionally, the study demonstrates that the physical model MMRT is a powerful tool for understanding enzyme temperature dependencies and dynamics at the single-molecule level.
ACS APPLIED NANO MATERIALS
(2021)