Biomedical Probes Research Articles

Core-Shell Interface Engineering Strategies for Modulating Energy Transfer in Rare Earth-Doped Nanoparticles.

Rare earth-doped nanoparticles (RENPs) are promising biomaterials with substantial potential in biomedical applications. Their multilayered core-shell structure design allows for more diverse uses, such as orthogonal excitation. However, the typical synthesis strategies-one-pot successive layer-by-layer (LBL) method and seed-assisted (SA) method-for creating multilayered RENPs show notable differences in spectral performance. To clarify this issue, a thorough comparative analysis of the elemental distribution and spectral characteristics of RENPs synthesized by these two strategies was conducted. The SA strategy, which avoids the partial mixing stage of shell and core precursors inherent in the LBL strategy, produces RENPs with a distinct interface in elemental distribution. This unique elemental distribution reduces unnecessary energy loss via energy transfer between heterogeneous elements in different shell layers. Consequently, the synthesis method choice can effectively modulate the spectral properties of RENPs. This discovery has been applied to the design of orthogonal RENP biomedical probes with appropriate dimensions, where the SA strategy introduces a refined inert interface to prevent unnecessary energy loss. Notably, this strategy has exhibited a 4.3-fold enhancement in NIR-II in vivo imaging and a 2.1-fold increase in reactive oxygen species (ROS)-related photodynamic therapy (PDT) orthogonal applications.

Mixed-Transducer Micro-Origami for Efficient Motion and Decoupled Sensing.

This work introduces a mixed-transducer micro-origami to achieve efficient vibration, controllable motion, and decoupled sensing. Existing micro-origami systems tend to have only one type of transducer (actuator/sensor), which limits their versatility and functionality because any given transducer system has a narrow range of advantageous working conditions. However, it is possible to harness the benefit of different micro-transducer systems to enhance the performance of functional micro-origami. More specifically, this work introduces a micro-origami system that can integrate the advantages of three transducer systems: strained morph (SM) systems, polymer based electro-thermal (ET) systems, and thin-film lead zirconate titanate (PZT) systems. A versatile photolithography fabrication process is introduced to build this mixed-transducer micro-origami system, and their performance is investigated through experiments and simulation models. This work shows that mixed-transducer micro-origami can achieve power efficient vibration with high frequency, large vibration ranges, and little degradation; can produce decoupled folding motion with good controllability; and can accomplish simultaneous sensing and actuation to detect and interact with external environments and small-scale samples. The superior performance of mixed-transducer micro-origami systems makes them promising tools for micro-manipulation, micro-assembly, biomedical probes, self-sensing metamaterials, and more.

Gum Arabic-stabilized upconverting nanoparticles for printing applications

Upconverting nanoparticles (UCNPs) have been proposed for a variety of applications ranging from biomedical probes to luminescent sensors and security tags. Yet, bringing UCNPs into real-life, technologically relevant products requires implementation into industry-friendly processes. The need for stable dispersions, clean films or dry powders challenges users who look for a way to use UCNPs. In this work, an ink formulation was developed that offers a straightforward way to print UCNPs on glass and metallic substrates. The use of Gum Arabic as biocompatible emulsifier allowed to implement the NaGdF4:Er,Yb/NaGdF4 core/shell UCNPs into water-based ink formulations without the need of complex surface chemistry. The formulation, based on water, glycerin, and propanediol, exhibited good stability and applicability for printing with a commercial aerosol jet printer. Bright upconversion emission was retained upon printing, and the obtained UCNP films were used in proof-of-concept luminescent thermal sensing.

Water-stable, biocompatible, and highly luminescent perovskite nanocrystals-embedded fiber-based paper for anti-counterfeiting applications

In this study, we present a promising and facile approach toward the fabrication of non-toxic, water-stable, and eco-friendly luminescent fiber paper composed of polycaprolactone (PCL) polymer and CsPbBr3@SiO2 core–shell perovskite nanocrystals. PCL-perovskite fiber paper was fabricated using a conventional electrospinning process. Transmission electron microscopy (TEM) clearly revealed incorporation of CsPbBr3@SiO2 nanocrystals in the fibers, while scanning electron microscopy (SEM) demonstrated that incorporation of CsPbBr3@SiO2 nanocrystals did not affect the surface and diameter of the PCL-perovskite fibers. In addition, thermogravimetric analysis (TGA) and contact angle measurements have demonstrated that the PCL-perovskite fibers exhibit excellent thermal and water stability. The fabricated PCL-perovskite fiber paper exhibited a bright green emission centered at 520 nm upon excitation by ultra-violet (UV) light (374 nm). We have demonstrated that fluorescent PCL-perovskite fiber paper is a promising candidate for anti-counterfeiting applications because various patterns can be printed on the paper, which only become visible after exposure to UV light at 365 nm. Cell proliferation tests revealed that the PCL-perovskite fibers are cytocompatibility. Consequently, they may be suitable for biocompatible anti-counterfeiting. The present study reveals that PCL-perovskite fibers may pave way toward next generation biomedical probe and anti-counterfeiting applications.Graphical

Biomedical applications of lanthanide complexes

Lanthanide complexes are definitely bioavailable and have a huge number of implementations in medical analysis and in diagnosis and treatment. Due to their chemical and magnetic properties their use in cancer treatment and therapy increases. Luminescent compounds used as light-emitting materials for biosensors, molecular imaging has gotten profound interest attention in biomedical probe. Gadolinium(III) continues to be the dominant starting material for contrast agent design used in MRI response as a function of a specific biomarker. Contrast agents of lanthanides in MRI show a capacity of effective instrument for tumor diagnosis. Lu (3), Eu (3) based complexes operates in chemotherapy act as therapeutic agent. Dysprosium based drug used in treatment of Rheumatoid arthritis. Gd (3), Sm (3), Nd (3) complexes focuses on detailed image of organs, which helps in detecting diseases in body. Lanthanides, which based on physical and spectral, have wide range of uses including fluorescent probes in biological experiments. This review paper goal is to highlight research on lanthanide compounds with biological and biomedical uses.

κ-Carrageenan Hydrogel as a Matrix for Therapeutic Enzyme Immobilization.

During the last few decades, polysaccharide hydrogels attract more and more attention as therapeutic protein delivery systems due to their biocompatibility and the simplicity of the biodegradation of natural polymers. The protein retention by and release from the polysaccharide gel network is regulated by geometry and physical interactions of protein with the matrix. In the present work, we studied the molecular details of interactions between κ-carrageenan and three lipases, namely the lipases from Candida rugosa, Mucor javanicus, and Rhizomucor miehei—which differ in their size and net charge—upon protein immobilization in microparticles of polysaccharide gel. The kinetics of protein release revealed the different capability of κ-carrageenan to retain lipases, which are generally negatively charged; that was shown to be in line with the energy of interactions between polysaccharides and positively charged epitopes on the protein surface. These data create a platform for the novel design of nanocarriers for biomedical probes of enzymatic origin.

(Invited) Kinetic Prediction of Reverse Intersystem Crossing in Thermally Activated Delayed Fluorescence Molecules

Reverse intersystem crossing (RISC), the endothermic spin-flip process of producing an emissive singlet exciton from a non-emissive triplet exciton, is of increasing interest for applications in organic electroluminescent materials, photocatalysts, and biomedical probes. Theoretical prediction of the rate constant of RISC (k RISC) may enable an efficient priori screening of new materials in chemical spaces; yet, the understanding of its kinetics in vastly different structures is challenging. Here, we demonstrate a theoretical expression that reproduces experimental k RISC ranging over five orders of magnitude in twenty different molecules. We show that the spin flip occurs across the singlet–triplet crossing seam involving a higher-lying triplet excited state where the semi-classical Marcus parabola is no longer valid.1 The present model also leads to a newly designed TADF molecule with high k RISC of 108 s–1.2 1. N. Aizawa, Y. Harabuchi, S. Maeda, Y.-J. Pu, Nat. Commun. 11, 3909 (2020).2. N. Aizawa, A. Matsumoto, T. Yasuda, Sci. Adv. 7, 5769 (2021). Figure 1

29Si Isotope-Enriched Silicon Nanoparticles for an Efficient Hyperpolarized Magnetic Resonance Imaging Probe.

Silicon particles have garnered attention as promising biomedical probes for hyperpolarized 29Si magnetic resonance imaging and spectroscopy. However, due to the limited levels of hyperpolarization for nanosized silicon particles, microscale silicon particles have primarily been the focus of dynamic nuclear polarization (DNP) applications, including in vivo magnetic resonance imaging (MRI). To address these current challenges, we developed a facile synthetic method for partially 29Si-enriched porous silicon nanoparticles (NPs) (160 nm) and examined their usability in hyperpolarized 29Si MRI agents with enhanced signals in spectroscopy and imaging. Hyperpolarization characteristics, such as the build-up constant, the depolarization time (T1), and the overall enhancement of the 29Si-enriched silicon NPs (10 and 15%), were thoroughly investigated and compared with those of a naturally abundant NP (4.7%). During optimal DNP conditions, the 15% enriched silicon NPs showed more than 16-fold higher enhancements─far beyond the enrichment ratio─than the naturally abundant sample, further improving the signal-to-noise ratio in in vivo 29Si MRI. The 29Si-enriched porous silicon NPs used in this work are potentially capable to serve as drug-delivery vehicles in addition to hyperpolarized 29Si in vivo, further enabling their potential future applicability as a theragnostic platform.

Polysaccharide-Based Hydrogels as Delivery Systems for Enzymatic Therapy, Vitamin and Diagnostic Treatment. Structure and Encapsulation Capacity

In the present work we made a comprehensive study of properties of the polysaccharide-based drug delivery systems as nanocarriers for several biomedical probes of different origin, namely the components of perspective enzymatic drugs, binase and lipase, vitamin B9 (folic acid) and brilliant green, as a model of medical contrasting agent. We provided a brief overview of our data on polysaccharide hydrogels, held together by a variety of physical crosslinks, as delivery systems for enzymatic therapy, vitamin and diagnostic treatment. During last decades hydrogels are widely used in drug delivery though their biocompatibility and simplicity of biodegradation. These materials represent biopolymer matrix, which can successfully being used for encapsulation of bioactive molecules, including enzymes, adjustable blocking of their activity, delivery and controllable release. We have shown that biomedical application of hydrogels can be hindered by the toxicity of crosslinking cations and CNT used as the modifying agent.

Designing Magnetic NanoMOFs for Biomedicine: Current Trends and Applications

Metal–organic frameworks (MOFs) have shown a great potential in biomedicine due to their promising applications in different fields, including drug delivery, thermometry, theranostics etc. In this context, the development of magnetic sub-micrometric or nanometric MOFs through miniaturization approaches of magnetic MOFs up to the nanoscale still represents a crucial step to fabricate biomedical probes, especially in the field of theranostic nanomedicine. Miniaturization processes have to be properly designed to tailor the size and shape of particles and to retain magnetic properties and high porosity in the same material, fundamental prerequisites to develop smart nanocarriers integrating simultaneously therapeutic and contrast agents for targeted chemotherapy or other specific clinical use. An overview of current trends on the design of magnetic nanoMOFs in the field of biomedicine, with particular emphasis on theranostics and bioimaging, is herein envisioned.

Chemical and Colloidal Dynamics of MnO2 Nanosheets in Biological Media Relevant for Nanosafety Assessment.

Many layered crystal phases can be exfoliated or assembled into ultrathin 2D nanosheets with novel properties not achievable by particulate or fibrous nanoforms. Among these 2D materials are manganese dioxide (MnO2 ) nanosheets, which have applications in batteries, catalysts, and biomedical probes. A novel feature of MnO2 is its sensitivity to chemical reduction leading to dissolution and Mn2+ release. Biodissolution is critical for nanosafety assessment of 2D materials, but the timing and location of MnO2 biodissolution in environmental or occupational exposure scenarios are poorly understood. This work investigates the chemical and colloidal dynamics of MnO2 nanosheets in biological media for environmental and human health risk assessment. MnO2 nanosheets are insoluble in most aqueous phases, but react with strong and weak reducing agents in biological fluid environments. In vitro, reductive dissolution can be slow enough in cell culture media for MnO2 internalization by cells in the form of intact nanosheets, which localize in vacuoles, react to deplete intracellular glutathione, and induce cytotoxicity that is likely mediated by intracellular Mn2+ release. The results are used to classify MnO2 nanosheets within a new hazard screening framework for 2D materials, and the implications of MnO2 transformations for nanotoxicity testing and nanosafety assessment are discussed.

In-Fiber Cascaded FPI Fabricated by Chemical-Assisted Femtosecond Laser Micromachining for Micro-Fluidic Sensing Applications

An ultra-compact cascaded Fabry Perot (F-P) interferometer in fiber, which exhibits a high-visibility and enhanced detection limit, has been developed by chemical-assisted femtosecond laser micromachining. The reflection spectrum of the cascaded F-P interferometer shows stronger and narrower resonance than single F-P cavity. The liquid refractive index (RI) measurement demonstrates that the wavelength sensitivity and the dip intensity sensitivity are ∼888 nm/RIU and −882 dB/nm/RIU, respectively, and the obtained detection limit is 4.22 × 10−5 RIU in RI range 1.325–1.330, which is higher than that of the conventional single F-P cavity in optical fibers based on wavelength modulation (10−4 RIU). Moreover, the gas pressure measurement demonstrates that the wavelength sensitivity is 2.86 nm/MPa and the detection limit reaches 1.311 × 10−2 MPa in pressure range 1.5–2.0 MPa. The proposed in-fiber cascaded F-P interferometer will find potential applications in chemical and biological sensors, biomedical probes, and low-cost care products.

Unveiling the Structure of MoS x Nanocrystals Produced upon Laser Fragmentation of MoS2 Platelets.

Transition-metal dichalcogenide MoS2 nanostructures have attracted tremendous attention due to their unique properties, which render them efficient nanoscale functional components for multiple applications ranging from sensors and biomedical probes to energy conversion and storage devices. However, despite the wide application range, the possibility to tune their size, shape, and composition is still a challenge. At the same time, the correlation of the structure with the optoelectronic properties is still unresolved. Here, we propose a new method to synthesize various morphologies of molybdenum sulfide nanocrystals, on the basis of ultrashort-pulsed laser fragmentation of MoS2 platelets. Depending on the irradiation conditions, multiple MoSx morphologies in the form of nanoribbons, nanospheres, and photoluminescent quantum dots are obtained. Besides the detailed structural analysis of the various crystals formed, the structure–property relation is investigated and discussed.

Two‐Component Aggregation‐Induced Emission Materials: Tunable One/Two‐Photon Luminescence and Stimuli‐Responsive Switches by Co‐Crystal Formation

AbstractMolecular materials with aggregation‐induced emission (AIE), which have been paid much attention recently, are important for applications in optoelectronic devices, chemical sensors, and biomedical probes. To date, single‐component AIE systems are largely developed; however, the knowledge on the aggregation emission properties for multicomponent systems is still rather limited. In this work, it is shown that the AIE can be further extended to two‐component molecular assemblies, with the (naphthylvinyl)pyridine (NP) as the model. The NP‐based two‐component solutions present typical AIE properties, and their aggregation/crystalline states (co‐crystals) further exhibit different fluorescence emission (blue/cyan/green) with variable photoluminescence quantum yields as high as 50.4%. The co‐crystals present adjustable two‐photon fluorescence emission that is absent for the pristine NP solid. Moreover, NP‐based co‐crystals represent smart luminescent switches with reversible changes upon external stimuli (such as heat and base vapor), and the fluorescence visualization can be easily monitored benefitting from their high‐efficiency photoemission and obvious color change. It can be expected that by virtue of facile design of intermolecular interactions (such as halogen/hydrogen bonds and π–π interactions) during co‐aggregation and/or co‐crystallization, the two‐component AIE materials can be readily extended to other fluorphore systems toward tuning high‐efficiency solid‐state emission, two‐photon luminescence, and stimuli‐responsive switching.

Маршруты биомедицинской сканирующей зондовой микроскопии

Маршруты биомедицинской сканирующей зондовой микроскопии

Functionality and versatility of aggregation-induced emission luminogens

Breakthrough innovations in light-emitting materials have opened new exciting avenues for science and technology over the last few decades. Aggregation-induced emission (AIE) represents one of such innovations. It refers to a unique light-emitting phenomenon, in which luminescent materials that are non-emissive in molecular state can be induced to emit efficiently in aggregated state. The design and development of AIE luminogens (AIEgens) have overcome technical and fundamental limitations that exist in conventional light-emitting materials, and thus generate great opportunities for various applications. In this review, we aim to introduce the wonderful world of AIE to scientists from different disciplines by summarizing the recent progress made in this exciting research field. The mechanistic analyses and the working principles of the AIE processes are first elaborated, which reveal the restriction of intramolecular motions as the main cause for the AIE effect. The different molecular engineering strategies for the design of new AIEgens are subsequently discussed with examples of various AIEgen systems. The recent high-tech applications of AIEgens as optoelectronic materials, chemical sensors, and biomedical probes are presented and discussed. We hope that this review will stimulate more research interest from physics, chemistry, life science, and biomedical fields to this wonderland of AIE.

Facile Synthesis of a Selective Biomolecule Chemosensor and Fabrication of Its Highly Fluorescent Graphene Complex.

A novel hydrophilic imidazolium fluorescent chemosensor has been utilized to prepare water-soluble fluorescent graphene complex via a facile ion-exchange strategy, which gives a very high quantum yield (0.87). The highly fluorescent graphene complex displays a close resemblance to the water-soluble fluorescent chemosensor, as the chemisorbed imidazolium hinders the electron transfer between the naphthalene moiety and the graphene. If the imidazolium is simply physisorbed on graphene by physical mixing, it does not show a high quantum yield because the π-π stacking between the naphthalene moiety and graphene leads to fluorescence quenching. The fluorescent chemosensor selectively detects RNA by turn-on fluorescence at physiological pH in aqueous solution. The fluorescent chemosensor as well as the fluorescent graphene complex would find potential applications as photoresponsive materials and biomedical probes.

Ultrasensitive Vertical Piezotronic Transistor Based on ZnO Twin Nanoplatelet.

High sensitivity of pressure/strain sensors is the key to accurately evaluating external mechanical stimuli and could become more important in future generations of human-machine interfaces and artificial skin. Here we report the study of a two-terminal piezotronic transistor based on ZnO twin nanoplatelets (TNPT). Owing to the mirror symmetrical structure of ZnO twin nanplatelet, compressive pressure-induced positive piezoelectric polarization charges created at both metal-semiconductor interfaces can simultaneously lower both Schottky barrier heights and thus significantly modulate the carrier transport. Our device exhibits the highest pressure sensitivity of 1448.08-1677.53 meV/MPa, which is more than ∼20 times larger than the highest value reported previously, and a fast response time of <5 ms. In addition, it can be used as a photodector with an ultrahigh external photoresponsivity of ∼1.45 × 104 AW-1, which is ∼105 times larger in magnitude than that of commercial UV photodetectors. The coupling between the mirror symmetrical structure and strong piezotronic effect in ZnO twin nanoplatelets may enable the development of ultrasensitive pressure/strain sensors for various applications such as artificial skin, health monitoring, and adaptive biomedical probes.

A four-dimensional snapshot hyperspectral video-endoscope for bio-imaging applications.

Hyperspectral imaging has proven significance in bio-imaging applications and it has the ability to capture up to several hundred images of different wavelengths offering relevant spectral signatures. To use hyperspectral imaging for in vivo monitoring and diagnosis of the internal body cavities, a snapshot hyperspectral video-endoscope is required. However, such reported systems provide only about 50 wavelengths. We have developed a four-dimensional snapshot hyperspectral video-endoscope with a spectral range of 400–1000 nm, which can detect 756 wavelengths for imaging, significantly more than such systems. Capturing the three-dimensional datacube sequentially gives the fourth dimension. All these are achieved through a flexible two-dimensional to one-dimensional fiber bundle. The potential of this custom designed and fabricated compact biomedical probe is demonstrated by imaging phantom tissue samples in reflectance and fluorescence imaging modalities. It is envisaged that this novel concept and developed probe will contribute significantly towards diagnostic in vivo biomedical imaging in the near future.

Chemical‐assisted femtosecond laser writing of optical resonator arrays

AbstractThe design of micro‐optical resonator arrays are introduced and tailored towards refractive index sensing applications, building on the previously unexplored benefits of open dielectric stacks. The resonant coupling of identical hollow cavities present strong and narrow spectral resonance bands beyond that available with a single Fabry Perot interferometer. Femtosecond laser irradiation with selective chemical etching is applied to precisely fabricate stacked and waveguide‐coupled open resonators into fused silica, taking advantage of small 12 nm rms surface roughness made available by the self‐alignment of nanograting planes. Refractive index sensing of methanol‐water solutions confirm a very attractive sensing resolution of 6.5 × 10−5 RIU. Such high finesse optical elements open a new realm of optofluidic sensing and integrated optical circuit concepts for detecting minute changes in sample properties against a control solution that may find importance in chemical and biological sensors, telecom sensing networks, biomedical probes, and low‐cost health care products. image