Detecting trace amounts of harmful bacteria and nanoscale biomarkers is essential for early diagnosis and disease prevention. However, conventional methods, such as cultivation and immunoassays, are time-consuming and suffer from limited biological sensitivity. To address these limitations, we developed a rapid and highly sensitive detection method based on optical condensation using a metallic thin-film-coated optical fibre module. Acting as a photothermal source, this module induces convection and bubble formation at the fibre tip, enabling efficient three-dimensional condensation of targets within liquid samples. When positioned away from the substrate, the module assembled 103-105 bacteria and microparticles from a 20 mu L sample within 60 s. This approach increased assembly efficiency by more than ten-fold compared with conventional two-dimensional photothermal methods, concentrating over 10% of all target objects through combined horizontal and vertical convection. These findings highlight the potential of this technique for advancing bioanalytical detection, drug delivery and material assembly technologies.

The present research demonstrates the application of light-induced enhancement of cellular uptake of genetic materials (DNA and siRNA) into the living suspension cells. Based on the position of the photothermal conversion substrate, two distinct experimental setups were evaluated: (1) the bottom surface of a cell culture plate coated with a gold nanofilm functioning as the substrate, and (2) a setup where a cover glass coated with a gold nanofilm functioning as the substrate was placed over the cell culture medium. In both setups, the near-infrared laser was focused onto the gold nanofilm, inducing convection in the extracellular medium through light-induced condensation of cells and genetic material. Despite not using any transfection reagents whatsoever, this experimental technique significantly promoted the cellular uptake, cytosolic release, and expression of the target genetic material. In particular, the setup (2) exhibited lower cytotoxicity after light irradiation compared to setup (1) due to the photothermally controlled Marangoni convection. Additionally, the simulation results also confirmed the superiority of this system. These results demonstrate that the inverted optical condensation with the photothermal source at the top of the reaction container has the potential to enhance the transfection of genetic material into suspension cells avoiding the damage, and such a mechanism would be used for highly efficient transfection of various biochemical substances leading to the unconventional drug delivery.

Chromium nitride (Cr 2 N) is a plasmonic material whose real part of the dielectric function becomes negative in the deep-ultraviolet region, enabling plasmon resonances to be tuned from the ultraviolet to the visible and near-infrared by structural design. Its relatively large imaginary part is also advantageous for thermoplasmonic applications. In addition, Cr 2 N exhibits a low thermal conductivity (12 W m -1 K -1 ) compared with that of noble metals. Here, we numerically demonstrate a U-shaped Cr2N nanostructure that generates four distinct surface temperature distributions, controlled solely by the polarization of monochromatic light at 1064 nm. Owing to its symmetry, the U-shaped structure supports different plasmon modes for horizontal and vertical linear polarizations, as well as for left- and right-handed circular polarizations. These mode differences lead to distinct Joule heating distributions that, due to the low thermal conductivity, are directly imprinted on the surface temperature patterns. As a result, the U-shaped nanostructure acts as a polarization-controlled nanoheater, exhibiting distinct temperature distributions for each polarization state. This result shows that surface temperature distributions can be controlled through plasmon mode design in nanostructures, analogous to the shaping of optical near fields by plasmon modes, which is important for thermoplasmonic applications.

Immunoassay methods such as enzyme-linked immunosorbent assay using antigen-antibody reactions have been applied to detect biomarker proteins in the case of various diseases (e.g., cancer). However, these methods comprise several-hour-long pre-treatment processes (incubation and washing) before detection, and their sensitivity is limited by the affinity of protein and antibody sets. Here, we demonstrate the rapid and highly sensitive analysis of a cancer biomarker at several hundreds of attograms using a microflow-type light-induced acceleration system (MF-LAC-SYS) to enhance the reaction between the multiple antibodies and glycoprotein (CEACAM-5) from human plasma containing multiple impurities with the help of theoretical analysis. Adjusting the surface charge of the antibody-modified beads and buffer solution components, we could detect pg mL-1 levels of CEACAM-5 at high sensitivity under a laser beam irradiation of several hundred mW for several minutes at a defocused condition equivalent to the microchannel width. Specifically, we discovered the existence of nanoscale CEACAM-5 aggregates related to the sensitivity of the MF-LAC-SYS, using dynamic light scattering and electron microscopy. The results will potentially pave the way for a platform using unconventional immunoassays for liquid biopsy and blood proteomics.

BACKGROUND:This prospective observational multicenter study aimed to provide evidence-based data on the risk factors for feeding tube dependence, oral intake level, and speech function after tongue reconstruction. PATIENTS AND METHODS:This study was conducted by the Oral Pharyngeal Esophageal Operation and Reconstruction Analytical group across 21 Japanese institutions. Patients with oral tongue squamous cell carcinoma who underwent microsurgical reconstruction following subtotal/total glossectomy were included. Functional evaluations were performed 1 year postoperatively. The primary endpoint was postoperative feeding tube dependence. The other outcome variables were oral intake level and speech function at the time of evaluation. RESULTS:Overall, 189 patients were enrolled, of whom 121 (64.0%) were followed up for 1 year after surgery and were eligible for the final analysis. The overall rate of feeding tube dependence was 12.4% (n = 15) at the primary endpoint. Univariate analysis revealed that tongue defect type, laryngeal suspension, and postoperative chemotherapy were associated with feeding tube dependence. The oral intake level was affected by age at surgery, laryngeal suspension, and postoperative chemoradiation. Speech function was affected by age at surgery, American Society of Anesthesiologists physical status (class 2), medical comorbidities of hypertension and cardiac dysrhythmia, primary tumor stage (T4), neck dissection, reconstructive procedure, laryngeal suspension, and postoperative radiation. CONCLUSIONS:This study provides useful data for estimating individual risk factors associated with feeding tube dependence, oral intake level, and speech function before tongue reconstruction. These results can help surgeons and patients make informed decisions and optimize the functional outcomes of tongue reconstruction.

The strong asymmetric optical response of plasmonic metal nanostructures to right- and left-handed circularly polarized light has attracted great interest in nanotechnology. However, when considering heat generation in these structures, the surface temperature distribution becomes nearly isothermal regardless of which handedness of circularly polarized light is used. This is because of the high thermal conductivity of noble metals and the diffusive nature of heat transfer. In this study, we experimentally show that the surface temperature patterns of chiral plasmonic nanostructures made from titanium nitride, which has a thermal conductivity less than 10% that of gold, become clearly different under right- and left-circularly polarized light, with the temperature contrast reaching several tens of kelvins. This temperature switching allows nanoscale spatial control of photothermal chemical reactions. Our findings suggest a significant potential for shaping nanoscale temperature distributions in the field of thermoplasmonics.

We present a theoretical investigation of polarization-and angle-dependent absorption in a monolayer graphene sheet embedded in a planar optical microcavity. By employing a matrix-based solution to Maxwell's equations, we resolve the reflection, transmission, and absorption spectra for arbitrary incidence angles and both s-and ppolarizations. Our analysis reveals that the optical absorption in graphene can be significantly enhanced-reaching up to 65% for s-polarized and 50% for p-polarized light-via resonant field confinement and interference effects within the cavity. The absorption is highly tunable with incidence angle, wavelength, and graphene position, offering potential for adaptive photonic devices such as polarization-sensitive detectors, angle-resolved sensors, and modulators. These findings contribute to the understanding of light-matter interaction in two-dimensional materials and provide a modeling framework relevant to nanophotonic and optoelectronic design. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

Emission of fluorescence in a specific direction generates an optical force in the opposite direction of the emission by the momentum conservation raw. This “emission force” can induce the directional transportation of small objects anisotropically emitting fluorescence from molecules in the objects only by photo‐irradiation without any spatio‐temporal control of light field. To demonstrate the movement by the emission force, we fabricated dye‐doped cylinder‐shaped polymer micro‐objects (PMOs) with gold thin films on their top surfaces. The single PMOs in water on a glass substrate, the side surfaces of which were facing to the substrate, were photoexcited with a continuous wave visible (532 nm) laser. The dyes in a PMO emitted strong fluorescence toward the non‐coated end (bottom) of the micro‐cylinder due to the reflection by the gold thin film on the top. The individual motions of the PMOs under photoexcitation are detected with fluorescence microscopy. Analysis of the trajectories of the PMOs confirmed that the anisotropic fluorescence emission led to the transportation of the PMOs in the opposite direction of the fluorescence. The emission force acting on the PMO is quantitatively evaluated through computational simulation considering the emission force and Brownian motion.

The unique characteristics of biological structures depend on the behavior of DNA sequences confined in a microscale cell under environmental fluctuations and dissipation. Here, we report a prominent difference in fluorescence from dye-modified single-stranded DNA in a light-induced assembly of DNA-functionalized heterogeneous probe particles in a microwell of several microliters in volume. Strong optical forces from the Mie scattering of microparticles accelerated hybridization, and the photothermal effect from the localized surface plasmons in gold nanoparticles enhanced specificity to reduce the fluorescence intensity of dye-modified DNA to a few %, even in a one-base mismatched sequence, enabling us to clearly highlight the single nucleotide polymorphisms in DNA. Fluorescence intensity was positively correlated with complementary DNA concentrations ranging in several tens fg/mu L after only 5 min of laser irradiation. Remarkably, a total amount of DNA in an optically assembled structure of heterogeneous probe particles was estimated between 2.36 ymol (2.36 x 10-24 mol) and 2.36 amol (2.36 x 10-18 mol) in the observed concentration range. These findings can promote an innovative production method of nanocomposite structures via biological molecules and biological sensing with simple strategies avoiding genetic amplification in a PCR-free manner.

Upon illumination, metallic nanostructures exhibiting localized surface plasmon resonance immersed in a liquid medium induce not only optical forces in the near-field, but also thermophoresis and fluid convection due to photothermal conversion. It is known that these thermally induced mass transport phenomena can, in some cases, assist in the trapping of matter by optical tweezers. Therefore, the ability to control the surface temperature of a nanostructure by modulating plasmonic modes could enhance the controllability of optothermal manipulation. However, since heat transfer is inherently a diffusive phenomenon, the surface temperature of noble metal nanostructures with high thermal conductivity tends to be uniform. Thus, controlling the surface temperature of a nanostructure via plasmonic modes is fundamentally challenging. In this study, we have numerically demonstrated that the surface temperature of titanium nitride nanostructures, which exhibit significantly lower thermal conductivity compared to noble metals, can be modulated by irradiating them with circularly polarized light.

Plasmonic substrates have been extensively investigated due to their potential applications in fluorescence microscopy, chemical sensing, and photochemical reactions. The optical properties of the substrate depend on the spatial and temporal features of the plasmon excited. Hence, the ability to directly visualize plasmon dynamics is crucial. In this study, we investigated the spatial and temporal properties of plasmon excitation in a plasmonic nanobowl substrate consisting of a periodic hexagonal array of nanoscale bowl-like structures developed with self-assembly. Near-field transmission imaging revealed that multiple plasmon resonance bands are observed from visible to near-infrared spectral region, and the optical contrast of the image is dependent on the observed band. Near-field two-photon photoluminescence microscopy revealed that the probability of excitation inside each nanoscale bowl-like structure is greater than that in the surrounding area. Near-field time-resolved imaging revealed that the nanobowl substrate exhibited a substantially long plasmon dephasing time, exceeding 12 fs. Based on the spectral features of the near-field and far-field spectra, we found that optically dark plasmon mode is excited by the near-field illumination and only partly contributes to the long dephasing time observed. This fact indicates that the dephasing time is extended by some other mechanism in the periodic substrate. We revealed from this study that the enhanced optical fields induced in the nanobowl structure originate from the photosynergetic effect of the cavity mode and plasmon mode excited.

Background:. Recently, significant inframalleolar disease seems to increase in chronic limb-threatening ischemia (CLTI) patients, making identifying sufficient outflow vessels in the foot challenging. In these difficult situations, free tissue transfer is a valuable tool to provide a low-resistance vascular bed to the affected part. However, there remains concern that free tissue transfer may impede adequate perfusion of the higher resistance diseased vascular bed. Methods:. To improve perfusion of the affected area directly, the authors have developed a concept of a free bypass flap, adding bypass surgery to free tissue transfer. After anastomosis with the recipient vessels in a conventional manner for free tissue transfer, bypass surgery to the foot is performed by anastomosis of the branch of the flap pedicle with the diseased artery to the foot. A retrospective chart review of nine CLTI patients was performed to analyze the outcomes of free bypass flap transfer between 2018 and 2023. Results:. The flap success rate was 100% (n = 9). Postoperative angiography or echo confirmed the patency of all but one bypass vessel (n = 8). There were six fatalities, however, due to causes other than foot lesions, with an average observation period of 16 months. The limb salvage rate was 89% (n = 8). Conclusions:. A free bypass flap enhances the overall blood circulation to the foot. Due to its high patency rate of bypass vessels, it is a valuable method for preserving the limbs of highly comorbid patients with CLTI.

The efficient detection of protein biomarkers is critical for public health. However, the sensitivity of conventional antigen test kits is relatively low for early diagnosis, and laboratory immunoassays require complex pretreatment processes overnight. If target nanomaterials could be remotely guided to the detection site, simpler and faster methods would be developed. Here, we reveal the mechanism of light-induced immunoassay that anti-spike-protein antibodies for SARS-CoV-2 were coated on our developed nanoparticle-imprinted plasmonic substrate (NPI-PS) over the submillimeter area within one minute and nanoparticles modified with spike proteins can be selectively detected within a few minutes at one or two orders of higher sensitivity via a two-step optical condensation using NPI-PS. NPI-PS exhibits high-performance optical condensation with high photothermal properties even under milliwatt-class nonresonant laser irradiation, enabling a wide range of quantitative measurements. These findings support an innovative strategy to mitigate pandemic threats and various diseases through the high-throughput detection of protein biomarkers.

We succeeded in selective detection of DNA by optical condensation with probe DNA-modified microparticle on a nano-bowl substrate. This method enables the quantitative measurement of DNA only by 10 mW laser irradiation for 5 minutes.

We developed a high survival rate optical condensation method based on multipoint laser irradiation to improve the photocurrent from photosynthetic microbes. Furthermore, we also investigated photocurrent change under the effects of thermal damage on microbes.

Detecting trace amounts of harmful bacteria and nanoscale biomarkers is essential for early diagnosis and preventing food poisoning and various diseases. Hindered by limited sensitivity and speed due to dilute samples, conventional detection methods, such as cultivation techniques and immunoassays, are expensive and time-consuming. In contrast, optical condensation using photothermal convection and bubbles facilitates rapid transport and dense assembly of dispersoids toward the observation area; however, its efficiency on two-dimensional substrates remains restricted. Here, to develop a more sensitive and rapid detection method using optical condensation, we introduce a metallic thin film-coated optical fibre module that serves as a photothermal source, generating convection and bubbles at the fibre tip. This leads to optical condensation at three-dimensionally arbitrary positions within the liquid. Notably, when the optical fibre module is positioned away from the substrate, 103-105 bacteria and microparticles in 20 μL liquid sample can be assembled at the fibre tip within 60 s. Furthermore, the assembly efficiency increases more than 10-fold, in comparison with the conventional two-dimensional photothermal assembly, exceeding 10% of all the disperoids due to horizontal and vertical convections from the fibre tip. Additionally, when the fibre module is placed on the substrate, target objects can be assembled not only at the fibre tip but also around the side wall of the fibre. Therefore, our findings demonstrate a significant enhancement in detection capabilities. This discovery paves the way for novel applications in bioanalytical technology, drug delivery systems, and material engineering.

Autologous costal cartilage grafts remain the gold standard method for microtia reconstruction. However, reports on its long-term outcomes are limited. We present two cases with >40-year outcomes after auricular reconstruction with autologous costal cartilage. A 56 year-old woman and a 53 year-old man presented to our institution with complaints of wire exposure. In both cases, the reconstructed ear was deformed. A computerized tomography scan revealed calcification of the reconstructed costal cartilage graft framework. To our knowledge, these cases present the longest outcomes (50 and 42 years for the 56 year-old woman and 53 year-old man, respectively) of microtia reconstruction using autologous cartilage grafts. We found that ear frameworks constructed from costal cartilage tended to calcify in the long term, as in the natural course of costal cartilage. Therefore, the possibility of calcification of costal cartilage grafts should be relayed to patients and parents, and lifelong surveillance after reconstruction should be recommended.

We succeeded in selective detection of SARS-CoV-2-derived S-protein-modified nanoparticles (SPMN) after optical coating of anti-body-modified nanoparticles by optical condensation with nano-bowl substrate. Particularly, antigen-antibody reaction can be accelerated by photothermal convection even in artificial saliva.

Much attention has been paid to the development of high-performance electrocatalytic reactions by exploiting the plasmonic properties of noble metal nanoparticles. In this study, ultrathin Pt layers with different coverage ratios were prepared on plasmonic octahedral Au nanoparticles (NPs) by underpotential deposition (UPD) of Cu followed by redox replacement with Pt. The effect of the Cu UPD cycle on the deposited Cu and redox-substituted Pt layers on octahedral Au NPs was investigated to evaluate the electrocatalytic activity of Pt-decorated octahedral NPs for the oxygen reduction reaction (ORR). By varying the number of cycles of Cu UPD and Pt replacement, the coverage by the Pt layer on the Au NPs could be easily controlled. The resulting Pt-coated octahedral Au NPs exhibited three times higher specific activity for ORR than commercial Pt/C nanocatalysts due to the deposited Pt layer reflecting the {111} plane of the core. The ORR activity of Pt-coated octahedral Au NPs could be enhanced by photoexcitation with monochromatic LED irradiation, and the increase in enhancement factor was even greater when irradiated with a wavelength that could efficiently excite the localized surface plasmon resonance (LSPR) of the NPs. Analysis shows that this improvement is due to improved diffusion of oxygen to the electrode.

Extracellular vesicles (EVs), including nanoscale exosomes and ectosomes, hold promise as biomarkers that provide information about the cell of origin through their cargo of nucleic acids and proteins, both on their surface and within. Here, we develop a detection method of EVs based on light-induced acceleration of specific binding between their surface and antibody-modified microparticles, using a controlled microflow with three-dimensional analysis by confocal microscopy. Our method successfully detected 103-104 nanoscale EVs in liquid samples as small as a 500 nanoliters within 5 minutes, with the ability to distinguish multiple membrane proteins. Remarkably, we achieved the specific detection of EVs secreted from living cancer cell lines with high linearity, without the need for a time-consuming ultracentrifugation process that can take several hours. Furthermore, the detection range can be controlled by adjusting the action range of optical force using a defocused laser, consistent with the theoretical calculations. These findings demonstrate an ultrafast, sensitive, and quantitative approach for measuring biological nanoparticles, enabling innovative analyses of cell-to-cell communication and early diagnosis of various diseases, including cancer.