Nature-Inspired Adhesive Catecholamine for Colorimetric Bioassays

Biomarker, Catecholamine, Melanogenesis, Adhesive colorant, Colorimetric assayBiomarkers are biological indicators of specific pathological conditions. By monitoring biomarkers, early disease diagnosis, and immediate treatment are possible. In conventional biomarker detection methods, complex protocols, additional equipment, and trained personnel are essential, limiting its application to a laboratory setting. Therefore, the colorimetric bioassay, which generates a visible signal in the presence of a target biomarker, has attracted attention. However, limitations of this assay type include low sensitivity and/or diffusion of the colorant resulting in the loss of spatial information. To address this limitation, we developed an enzyme-mediated adhesive colorant (EAC) platform. Unlike previous biomarker detection platforms that require additional equipment for the readout, in the EAC platform, pyrocatechol (PC) is oxidized/polymerized by horseradish peroxidase (HRP) to generate a colorimetric signal that can be detected with the naked eye. As a large number of PC are oxidized by a single HRP, signal amplification occurs. In addition, the chemical structure of the colorant is similar to polydopamine, a well-known universal surface adhesive, resulting in a unique adhesion property. That is, the generated adhesive colorant is attached in the vicinity of the HRP labeled target, allowing spatial analysis of the target. The broad use of the EAC platform was confirmed by applying the protocol to single-cell staining assays and paper-based bioassays.YI. INTRODUCTION II. EXPERIMENTAL SECTION III. RESULTS AND DISCUSSION 3.1 Advantage of enzyme-mediated adhesive colorant (EAC) platform 3.2 Catechol oxidation via representative oxidases 3.3 Colorant generation of potential adhesive colorants 3.4 Limitations of conventional colorimetric bioassay using TMB 3.5 Adhesive property of potential adhesive colorant 3.6 EAC platform for ELISA 3.7 Single cell staining using adhesive colorant 3.8 EAC platform for paper-based bioassays IV. CONCLUSION V. REFERENCE바이오마커는 병리학적 상태의 변화를 알려주는 지표이며 바이오마커를 검출함으로써 질병의 초기 진단이 가능하다. 기존 바이오마커 검출 방법은 복잡한 프로토콜을 거쳐 전문가에 의해 진행되었으며 결과 판독에 추가 장비가 필요했기 때문에 일반 가정에서 사용될 수 없었다. 따라서 표적 바이오마커의 유무에 따라 눈에 보이는 신호를 형성해 결과 판독에 추가 장비가 필요 없는 비색 분석법이 최근 주목을 받고 있다. 하지만 기존에 사용되던 비색 분석법의 낮은 감도 또는 분자 프로브의 즉각적인 확산으로 인한 공간적 표적 분석의 한계에 의해 그 활용성이 떨어졌다. 따라서 우리는 효소에 의해 증폭된 신호가 표적이 존재하는 공간에 접착함으로써 기존 비색 분석법의 문제점을 해결할 수 있는 enzyme-mediated adhesive colorant 플랫폼 (EAC 플랫폼)을 디자인했다. 이전의 바이오마커 검출 플랫폼이 결과값을 얻기 위해 추가 기기가 필요한 것과 다르게 EAC 플랫폼에서는 피로카테콜 용액이 바이오마커에 표지 된 산화효소에 의해 산화/고분자화 되어 맨눈으로 검출가능한 비색 신호를 형성한다. 또한 생성된 비색 신호의 화학구조는 만능 접착제인 폴리도파민의 화학구조와 매우 유사하여 접착력을 가진다. 즉, 형성됨과 동시에 산화효소가 존재하는 부근에 접착되기 때문에 신호의 고정화를 통한 바이오마커의 공간적 분석을 가능하게 한다. 더 나아가 단일 세포 염색 분석과 paper-based bioassay인 Dot-blot assay 등에 해당 플랫폼을 적용시킴으로써 플랫폼의 폭 넓은 활용가능성을 입증했다.MasterdCollectio

Suppression of disorder-induced scattering in optomechanical systems

High-Q optical and mechanical resonators have been utilized in ultra-high precision metrology, transducers, sensor applications, and even investigating quantum mechanics at mesoscales. However, these low-loss devices are often limited by sub-wavelength fluctuations within the host material, that may be frozen-in or even dynamically induced. Rayleigh scattering is observed in nearly all wave-guiding technologies today and can lead to both irreversible radiative losses as well as undesirable intermodal coupling. The mitigation of disorder-induced scattering is extremely challenging for micro and nanoscale devices, as surface roughness, which causes Rayleigh scattering, is unavoidable in microfabrication processes (Appl Phys Lett 85, 17, 2004; J Lightwave Technol 24, 12, 2006). Minimizing disorder-induced Rayleigh backscattering has thus been a significant challenge until now. It has been shown that backscattering from disorder can be suppressed by breaking time-reversal symmetry in magneto-optic (Sov Phys JETP, 59, 1, 1984; Phys Rev B, 37, 1988) and topological insulator materials (Phys Rev B, 38, 1988; Nature, 461, 7265, 2009). Yet, common monolithic dielectrics, which are basic building ingredients of high-Q resonators, possess neither of these properties. Fortunately, we develop a novel technique to break time-reversal symmetry without magneto-optic in a high-Q optical cavity pumped by a single-frequency laser through parity-selective optomechanics. Such optomechanical interaction is achieved by Brillouin scattering, owing to the phase-matching condition. This method enables complete linear optical isolation without requiring magnetic fields. Instead, the isolation originates from a nonreciprocal induced transparency based on a coherent light-sound interaction, where light and sound are coupled bv a traveling-wave Brillouin scattering interaction. That breaks time-reversal symmetry within the waveguide-resonator system. Our result demonstrates that material agnostic and wavelength-agnostic optical isolation is far more accessible in chip-scale photonics than previously thought. However, isolators block backscattering from systems, but cannot prevent disorder-induced backscattering inherently. In order to minimize disorder-induced backscattering, we experimentally demonstrate robust phonon transport in the presence of material disorder. This is achieved by explicitly inducing chirality through the parity-selective optomechanical coupling. We show that asymmetric optical pumping of a symmetric resonator enables a dramatic chiral cooling of clockwise and counterclockwise phonons, while simultaneously suppressing the hidden action of disorder. Surprisingly, this passive mechanism is also accompanied by a chiral reduction in heat load leading to optical cooling of the mechanics without added damping, an effect that has no optical analog. This technique can potentially improve upon the fundamental thermal limits of resonant mechanical sensors, which cannot be attained through sideband cooling. This new mechanism can be also expanded to the optics domain, where Rayleigh scattering severely limits the performance of devices in the limit of microscale. We have demonstrated an optomechanical approach for dynamically suppressing Rayleigh light backscattering within optical resonators. Similar to the previous method, we achieve this by locally breaking time-reversal symmetry in a silica resonator through a Brillouin scattering interaction that is available in all materials. Near-complete suppression of Rayleigh backscattering is experimentally confirmed through three independent measurements -- the reduction of the back-reflections caused by scatterers, the elimination of a commonly seen normal-mode splitting effect, and by measurement of the reduction in intrinsic optical loss. More broadly, our results suggest that it is possible to dynamically suppress Rayleigh backscattering within any optical dielectric medium using time-reversal symmetry breaking, for achieving robust light propagation in spite of scatterers or defects. Our proposal is not limited by a specific form of time-reversal symmetry breaking through Brillouin scattering in optical cavities. It can be realized in linear waveguides under different time-reversal symmetry approaches such as acousto-optic, nonlinear-optics, and PT symmetry breaking technique

Beyond Bounds on Light Scattering with Complex Frequency Excitations

Light scattering is one of the most established wave phenomena in optics, lying at the heart of light-matter interactions and of crucial importance for nanophotonic applications. Passivity, causality and energy conservation imply strict bounds on the degree of control over scattering from small particles, with implications on the performance of many optical devices. Here, we demonstrate that these bounds can be surpassed by considering excitations at complex frequencies, yielding extreme scattering responses as tailored nanoparticles reach a quasi-steady-state regime. These mechanisms can be used to engineer light scattering of nanostructures beyond conventional limits for noninvasive sensing, imaging, and nanoscale light manipulation

Loss compensation and super-resolution with excitations at complex frequencies

Abbe diffraction limit fundamentally bounds the resolution of conventional optical imaging and spectroscopic systems. Along the years, several schemes have been introduced to overcome this limit, each offering opportunities and trade-offs. Metamaterials have been proposed as a promising platform in this context, in principle enabling superlenses capable of drastic resolution enhancements. However, their performance is severely hindered by material loss and nonlocal phenomena, which become increasingly more detrimental as we attempt to image more subwavelength details. Active metamaterials have been explored to overcome these challenges, however material gain introduces other obstacles, e.g., instabilities, nonlinearities and noise. Here, we demonstrate that the temporal excitation of passive superlenses using signals oscillating at complex frequencies compensates material loss, leading to resolution enhancement. Our results demonstrate that virtual gain stemming from tailored forms of excitation can tackle the impact of loss in superlenses. More broadly, our work opens promising avenues for loss compensation in metamaterials, with a broad range of applications extendable to optics and nanophotonic systems.Comment: 19 pages, 4 figure

Nature‐Inspired Adhesive Catecholamines for Highly Concentrated Colorimetric Signal in Spatial Biomarker Labeling

Colorants have been utilized for precise biomarker detection in rapid and convenient colorimetric bioassays. However, the diffusion of colorants in solution often results in poor sensitivity, which is a major obstacle to the clinical translation of current colorants. To address this issue, in the current study, a unique colorant is developed that possesses adhesiveness for concentration near the target biomarker, avoiding diffusion. In nature, the synergistic interplay between catechol and amine functional groups is thought to be key for the unique mechanism of marine mussel adhesion. In addition, polymerized catecholamines are found in nature as biopigments, that is, in melanin. The dual role of catechol/catecholamine moieties in natural organics inspire to design novel colorimetric bioassays based on an adhesive colorant. Horseradish peroxidase (HRP) is used to initiate in situ polymerization of the catecholic precursors with amine-containing additive molecules and simultaneously attach them near the HRP-labeled biomarkers. This novel catecholamine-based adhesive colorant provides an excellent quantitative (naked-eye) visible signal and it also generates superb spatial information on the biomarkers on complex surfaces (e.g., cell membranes). © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimFALS