Advances in optoplasmonic sensors – combining optical nano/microcavities and photonic crystals with plasmonic nanostructures and nanoparticles

AbstractNanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. A new class of nanophotonic architecture has emerged by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single-molecule detection and even single-ion sensing. The coupled photonic-plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. These optoplasmonic sensor structures could be the centrepiece of miniaturised analytical laboratories, on a chip, with detection capabilities that are beyond the current state of the art. In this paper, we review this burgeoning field of optoplasmonic biosensors. We first focus on the state of the art in nanoplasmonic sensor structures, high quality factor optical microcavities, and photonic crystals separately before proceeding to an outline of the most recent advances in hybrid sensor systems. We discuss the physics of this modality in brief and each of its underlying parts, then the prospects as well as challenges when integrating dielectric nano/microcavities with metal nanostructures. In Section 5, we hint to possible future applications of optoplasmonic sensing platforms which offer many degrees of freedom towards biomedical diagnostics at the level of single molecules

Remotely Light‐Powered Soft Fluidic Actuators Based on Plasmonic‐Driven Phase Transitions in Elastic Constraint

Materials capable of actuation through remote stimuli are crucial for untethering soft robotic systems from hardware for powering and control. Fluidic actuation is one of the most applied and versatile actuation strategies in soft robotics. Here, the first macroscale soft fluidic actuator is derived that operates remotely powered and controlled by light through a plasmonically induced phase transition in an elastomeric constraint. A multiphase assembly of a liquid layer of concentrated gold nanoparticles in a silicone or styrene–ethylene–butylene–styrene elastic pocket forms the actuator. Upon laser excitation, the nanoparticles convert light of specific wavelength into heat and initiate a liquid‐to‐gas phase transition. The related pressure increase inflates the elastomers in response to laser wavelength, intensity, direction, and on–off pulses. During laser‐off periods, heating halts and condensation of the gas phase renders the actuation reversible. The versatile multiphase materials actuate—like soft "steam engines"—a variety of soft robotic structures (soft valve, pnue‐net structure, crawling robot, pump) and are capable of operating in different environments (air, water, biological tissue) in a single configuration. Tailored toward the near‐infrared window of biological tissue, the structures actuate also through animal tissue for potential medical soft robotic applications

Selective Stiffening in Soft Actuators by Triggered Phase Transition of Hydrogel-Filled Elastomers

Nature has inspired a new generation of robots that not only imitate the behavior of natural systems but also share their adaptability to the environment and level of compliance due to the materials used to manufacture them, which are typically made of soft matter. In order to be adaptable and compliant, these robots need to be able to locally change the mechanical properties of their soft material-based bodies according to external feedback. In this work, a soft actuator that embodies a highly controllable thermo-responsive hydrogel and changes its stiffness on direct stimulation is proposed. At a critical temperature, this stimulation triggers the reversible transition of the hydrogel, which locally stiffens the elastomeric containment at the targeted location. By dividing the actuator into multiple sections, it is possible to control its macroscopic behavior as a function of the stiffened sections. These properties are evaluated by arranging three actuators into a gripper configuration used to grasp objects. The results clearly show that the approach can be used to develop soft actuators that can modify their mechanical properties on-demand in order to conform to objects or to exert the required force

Left ventricular long axis strain: a new prognosticator in non-ischemic dilated cardiomyopathy?

Background: Long axis strain (LAS) has been shown to be a fast assessable parameter representing global left ventricular (LV) longitudinal function in cardiovascular magnetic resonance (CMR). However, the prognostic value of LAS in cardiomyopathies with reduced left ventricular ejection fraction (LVEF) has not been evaluated yet. Methods and results: In 146 subjects with non-ischemic dilated cardiomyopathy (NIDCM, LVEF ≤45 %) LAS was assessed retrospectively from standard non-contrast SSFP cine sequences by measuring the distance between the epicardial border of the left ventricular apex and the midpoint of a line connecting the origins of the mitral valve leaflets in end-systole and end-diastole. The final values were calculated according to the strain formula. The primary endpoint of the study was defined as a combination of cardiac death, heart transplantation or aborted sudden cardiac death and occurred in 24 subjects during follow-up. Patients with LAS values > −5 % showed a significant higher rate of cardiac events independent of the presence of late gadolinium enhancement (LGE). The multivariate Cox regression analysis revealed that LVEDV/BSA (HR: 1.01, p  −10 % and the presence of LGE, patients with 3 points had a significantly higher risk for cardiac events than those with 2 or less points. Conclusion: Assessment of long axis function with LAS offers significant incremental information for the prediction of cardiac events in NIDCM and improves risk stratification beyond established CMR parameters

Common diseases alter the physiological age-related blood microRNA profile

Aging is a key risk factor for chronic diseases of the elderly. MicroRNAs regulate post-transcriptional gene silencing through base-pair binding on their target mRNAs. We identified nonlinear changes in age-related microRNAs by analyzing whole blood from 1334 healthy individuals. We observed a larger influence of the age as compared to the sex and provide evidence for a shift to the 5' mature form of miRNAs in healthy aging. The addition of 3059 diseased patients uncovered pan-disease and disease-specific alterations in aging profiles. Disease biomarker sets for all diseases were different between young and old patients. Computational deconvolution of whole-blood miRNAs into blood cell types suggests that cell intrinsic gene expression changes may impart greater significance than cell abundance changes to the whole blood miRNA profile. Altogether, these data provide a foundation for understanding the relationship between healthy aging and disease, and for the development of age-specific disease biomarkers

Ordered Surface Structuring of Spherical Colloids with Binary Nanoparticle Superlattices

Surface-patterning colloidal matter in the sub-10 nm regime generates exceptional functionality in biology and photonic and electronic materials. Techniques of artificially generating functional patterns in the small nanoscale advanced in a fascinating manner in the last several years. However, they remain often restricted to planar and noncolloidal substrates. Patterning colloidal matter in solution via bottom-up assembly of smaller subunits on larger core particles is highly challenging because it is necessary to force the subunits onto randomly moving objects. Consequently, the non-equilibrium conditions present during nanoparticle self-assembly are difficult to control to eventually achieve the desired material structures. Here, we describe the formation of surface patterns with intrinsic periodic repeats of 8.9 ± 0.9 nm and less on hard, amorphous colloidal core particles by assembling binary nanoparticle superlattices on the curved particle surface. The colloidal environment is preserved during the entire bottom-up crystallization of variable building blocks (here, monodispersed 5 nm Au and 2.4 nm Pd nanoparticles (NPs) and 230 nm SiO core particles) into AB -like, binary, and isotropic superlattice domains on the amorphous cores. The three-dimensional, bottom-up assembly technique is a new tool for patterning colloidal matter in the sub-10 nm surface regime for gaining access to multicomponent metamaterials for bionanoscience, photonics, and electronics. 2 13Irish Research CouncilScience Foundation Ireland -- replaceGerman Research Foundation (DFG

Synthesis, characterization and programmable toxicity of iron oxide nanoparticles conjugated with D-amino acid oxidase

D-amino acid oxidase (DAAO) is an enzyme which generates reactive oxygen species (ROS) and it is believed to have potential uses as a novel therapeutic molecule if internalized by cancer cells or if they are localized close to their plasma membrane. When conjugated onto iron oxide nanoparticles (NPs), the enzyme can be magnetically directed to targeted locations with an increased efficacy. A subsequent injection of DAAO substrate D-alanine can initiate ROS production and induce apoptosis of cells surrounding the NP-DAAO complex. Here, we describe a platform for optimal bioconjugation using monodisperse γ-Fe2O3 NPs (∼10 nm) resulting in high DAAO loading, stable NP-DAAO dispersions and more than 90% enzymatic activity recovery, which is retained using the particles in human serum. Lastly, since the NP-DAAO system is designed for cancer therapy, we proved its efficacy in killing SKOV-3, U87 and HCT-116 cancer cells.European Commission Horizon 2020Science Foundation IrelandGerman Research Foundation (DFG

Synthesis, characterization and programmable toxicity of iron oxide nanoparticles conjugated with D-amino acid oxidase

D-amino acid oxidase (DAAO) is an enzyme which generates reactive oxygen species (ROS) and it is believed to have potential uses as a novel therapeutic molecule if internalized by cancer cells or if they are localized close to their plasma membrane. When conjugated onto iron oxide nanoparticles (NPs), the enzyme can be magnetically directed to targeted locations with an increased efficacy. A subsequent injection of DAAO substrate D-alanine can initiate ROS production and induce apoptosis of cells surrounding the NP-DAAO complex. Here, we describe a platform for optimal bioconjugation using monodisperse γ-Fe2O3 NPs (∼10 nm) resulting in high DAAO loading, stable NP-DAAO dispersions and more than 90% enzymatic activity recovery, which is retained using the particles in human serum. Lastly, since the NP-DAAO system is designed for cancer therapy, we proved its efficacy in killing SKOV-3, U87 and HCT-116 cancer cells.European Commission Horizon 2020Science Foundation IrelandGerman Research Foundation (DFG

Outcome Analysis of Distal Radius Fracture with Orthosis Versus Cast Immobilization after Palmar Plate Osteosynthesis: A Randomized Controlled Study

Although the benefits of hand orthoses were shown in previous studies, they have not been able to establish themselves in clinical routines. With a focus on patient satisfaction, this study aimed to evaluate the latest generation of hand orthoses after palmar plate osteosynthesis for isolated distal radius fractures in comparison with circular plaster casts. 50 patients (16% dropout rate) were randomly assigned to an orthotic group (immobilization by orthosis, OG) or a control group (immobilization by a plaster cast, CG). Intra-articular fractures were present in 74% of the cases, and unstable AO C3 fractures in 26%. Questionnaires on patient satisfaction, documentation of the time required, clinical scores (DASH, SF-36), range of motion, grip measurements and radiographs were used for evaluation. The OG proved to be equivalent to the plaster treatment in terms of patient satisfaction, and stability of the reduction, as well as clinical scores DASH and SF-36. The OG was even superior in terms of personal hygiene (p = 0.011), handling (p = 0.008) and better adaptability (p = 0.013). Significantly less time was required to apply the orthosis (p < 0.001). In addition to the good results achieved so far, the study showed that the latest generation of orthoses has several advantages over plaster cast therapy, and could therefore become established in everyday clinical practice