SARS-CoV-2 Variant Screening Using a Virus-Receptor-Based Electrical Biosensor.

SARS-CoV-2 variants are of particular interest because they can potentially increase the transmissibility and virulence of COVID-19 or reduce the effectiveness of available vaccines. However, screening SARS-CoV-2 variants is a challenge because biosensors target viral components that can mutate. One promising strategy is to screen variants via angiotensin-converting enzyme 2 (ACE2), a virus receptor shared by all known SARS-CoV-2 variants. Here we designed a highly sensitive and portable COVID-19 screening biosensor based on the virus receptor. We chose a dual-gate field-effect transistor to overcome the low sensitivity of virus-receptor-based biosensors. To optimize the biosensor, we introduced a synthetic virus that mimics the important features of SARS-CoV-2 (size, bilayer structure, and composition). The developed biosensor successfully detected SARS-CoV-2 in 20 min and showed sensitivity comparable to that of molecular diagnostic tests (∼165 copies/mL). Our results indicate that a virus-receptor-based biosensor can be an effective strategy for screening infectious diseases to prevent pandemics.

Stimuli-Responsive Adaptive Nanotoxin to Directly Penetrate the Cellular Membrane by Molecular Folding and Unfolding.

Biological nanomachines, including proteins and nucleic acids whose function is activated by conformational changes, are involved in every biological process, in which their dynamic and responsive behaviors are controlled by supramolecular recognition. The development of artificial nanomachines that mimic the biological functions for potential application as therapeutics is emerging; however, it is still limited to the lower hierarchical level of the molecular components. In this work, we report a synthetic machinery nanostructure in which actuatable molecular components are integrated into a hierarchical nanomaterial in response to external stimuli to regulate biological functions. Two nanometers core-sized gold nanoparticles are covered with ligand layers as actuatable components, whose folding/unfolding motional response to the cellular environment enables the direct penetration of the nanoparticles across the cellular membrane to disrupt intracellular organelles. Furthermore, the pH-responsive conformational movements of the molecular components can induce the apoptosis of cancer cells. This strategy based on the mechanical motion of molecular components on a hierarchical nanocluster would be useful to design biomimetic nanotoxins.

The dopaminergic alterations induced by 4-F-PCP and 4-Keto-PCP may enhance their drug-induced rewarding and reinforcing effects: Implications for abuse.

Novel psychoactive substances remain the popular recreational drugs of use over the years. They continue to bypass government restrictions due to their synthesis and modifications. Recent additions to the lists are the 4-F-PCP and 4-Keto-PCP, analogs of the drug phencyclidine (PCP) known to induce adverse effects and abuse potential. However, studies on the abuse potential of 4-F-PCP and 4-Keto-PCP remain scarce. The rewarding and reinforcing effects of the drugs were assessed using conditioned place preference (CPP), self-administration, and locomotor sensitization tests. Dopamine (DA) receptor antagonists (SCH23390 and haloperidol) were administered during CPP to evaluate the involvement of the mesolimbic dopaminergic system. DA-related protein expression in the nucleus accumbens (NAcc) and ventral tegmental area (VTA) was measured. Additionally, phosphorylated cyclic-adenosine monophosphate-activated protein (AMP) response element-binding (p-CREB) protein, deltaFosB (∆FosB), and brain-derived neurotrophic factor (BDNF) protein levels in the NAcc were measured to assess the addiction neural plasticity effect of the drugs. Both 4-F-PCP and 4-Keto-PCP-induced CPP and self-administration; however, only 4-F-PCP elicited locomotor sensitization. Treatment with DA receptor antagonists (SH23390 and haloperidol) inhibited the 4-F- and 4-Keto-induced CPP. Both substances altered the levels of DA receptor D1 (DRD1), thyroxine hydroxylase (TH), DA receptor D2 (DRD2), p-CREB, ∆FosB, and BDNF. The results suggest that 4-F-PCP and 4-Keto-PCP may induce abuse potential in rodents via alterations in dopaminergic system accompanied by addiction neural plasticity.

Marker-Based Structural Displacement Measurement Models with Camera Movement Error Correction Using Image Matching and Anomaly Detection.

To prevent collapse accidents at construction sites, the marker-based displacement measurement method was developed. However, it has difficulty in obtaining accurate measurements at long distances (>50 m) in an outdoor environment because of camera movements. To overcome this problem, marker-based structural displacement measurement models using image matching and anomaly detection were designed in this study. Then, the performance of each model in terms of camera movement error correction was verified through comparison with that of a conventional model. The results show that the systematic errors due to camera movements (<1.7°) were corrected. The detection rate of markers with displacement reached 95%, and the probability that the error size would be less than 10 mm was ≥ 95% with a 95% confidence interval at a distance of more than 100 m. Moreover, the normalized mean square error was less than 0.1. The models developed in this study can measure the pure displacement of an object without the systematic errors caused by camera movements. Furthermore, these models can be used to measure the displacements of distant structures using closed-circuit television cameras and markers in an outdoor environment with high accuracy.

Solubilization of Hydrophobic Catalysts Using Nanoparticle Hosts.

A modular strategy for the solubilization and protection of hydrophobic transition metal catalysts using the hydrophobic pockets of water soluble gold nanoparticles is reported. Besides preserving original catalyst activity, this encapsulation strategy provides a protective environment for the hydrophobic catalyst and brings reusability. This system provides a versatile platform for the encapsulation of different hydrophobic transition metal catalysts, allowing a wide range of catalysis in water while uniting the advantages of homogeneous and heterogeneous catalysis in the same system.

Co-delivery of protein and small molecule therapeutics using nanoparticle-stabilized nanocapsules.

Combination therapy employing proteins and small molecules provides access to synergistic treatment strategies. Co-delivery of these two payloads is challenging due to the divergent physicochemical properties of small molecule and protein cargos. Nanoparticle-stabilized nanocapsules (NPSCs) are promising for combination treatment strategies since they have the potential to deliver small molecule drugs and proteins simultaneously into the cytosol. In this study, we loaded paclitaxel into the hydrophobic core of the NPSC and self-assembled caspase-3 and nanoparticles on the capsule surface. The resulting combination NPSCs showed higher cytotoxicity than either of the single agent NPSCs, with synergistic action established using combination index values.

Immobilization and stabilization of lipase (CaLB) through hierarchical interfacial assembly.

Nanostructure-enabled hierarchical assembly holds promise for efficient biocatalyst immobilization for improved stability in bioprocessing. In this work we demonstrate the use of a hierarchical assembly immobilization strategy to enhance the physicochemical properties and stability of lipase B from Candida antarctica (CaLB). CaLB was complexed with iron oxide nanoparticles followed by interfacial assembly at the surface of an oil-in-water emulsion. Subsequent ring opening polymerization of the oil provided cross-linked microparticles that displayed an increase in catalytic efficiency when compared to the native enzyme and Novozym 435. The hierarchical immobilized enzyme assembly showed no leakage from the support in 50% acetonitrile and could be magnetically recovered across five cycles. Immobilized lipase exhibited enhanced thermal and pH stability, providing 72% activity retention after 24 h at 50 °C (pH 7.0) and 62% activity retention after 24 h at pH 3.0 (30 °C); conditions resulting in complete deactivation of the native lipase.

Fabrication of multiresponsive bioactive nanocapsules through orthogonal self-assembly.

Multifunctional self-assembled systems present platforms for fundamental research and practical applications as they provide tunability of structure, functionality, and stimuli responsiveness. Pragmatic structures for biological applications have multiple design requirements, including control of size, stability, and environmental response. Here we present the fabrication of multifunctional nanoparticle-stabilized capsules (NPSCs) by using a set of orthogonal supramolecular interactions. In these capsules, fluorescent proteins are attached to quantum dots through polyhistidine coordination. These anionic assemblies interact laterally with cationic gold nanoparticles that are anchored to the fatty acid core through guanidinium-carboxylate interactions. The lipophilic core then provides a reservoir for hydrophobic endosome-disrupting agents, thereby generating a system featuring stimuli-responsive release of a payload into the cytosol with fluorescence monitoring.

Engineered Hybrid Vesicles and Cellular Internalization in Mammary Cancer Cells.

Extracellular vesicles play an important role in intercellular communication, with the potential to serve as biomaterials for nanocarriers. Combining such extracellular vesicles and liposomes results in advanced drug delivery carriers. In this study, we attempted to fabricate hybrid vesicles using a membrane fusion method and incorporated an anticancer drug. As a result, we successfully prepared nanosized uniform hybrid vesicles and evaluated their physicochemical characteristics and intracellular uptake mechanisms via endocytosis in various cell lines. Compared to liposomes, the hybrid vesicles showed better physical properties and a relatively higher reduction in cell viability, which was presumably dependent on the specific cell type. These findings suggest that fusion-based hybrid vesicles offer a novel strategy for delivering therapeutic agents and provide insights into the types of extracellular vesicles that are useful in fabricating hybrid vesicles to develop an advanced drug delivery system.

ZnO/Graphene Oxide on Halloysite Nanotubes as a Superabsorbent Nanocomposite Photocatalyst for the Degradation of Organic Dyes.

Using renewable photocatalysts for pollutant degradation represents a promising approach to addressing environmental water challenges by harnessing solar energy without additional energy consumption. However, for the practical use of photocatalysts, it is necessary to improve catalyst efficiency, considering cost and biocompatibility. In this study, we developed a new superabsorbent photocatalyst for the degradation of organic dyes in water. Our photocatalyst comprises halloysite nanotubes (HNTs) with a large outer diameter and Si-O and Al-O groups on the outer and inner surfaces, respectively; graphene oxide (GO) possessing numerous sp2 bonds and light-conductive properties; and ZnO, which can degrade organic molecules via a photon source. By exploiting the superabsorbent properties of GOs for organic dyes and stabilizing ZnO nanoparticles on HNTs to inhibit aggregation, our photocatalysts demonstrated significantly improved degradability compared to ZnO nanoparticles alone and combinations of ZnO with HNTs or GO. The structural characteristics of the nanocomposites were characterized using SEM, EDX, Raman spectroscopy, and XRD. Their enhanced photocatalytic activity was demonstrated by the degradation of rhodamine b in water, showing 95% photodegradation under UV illumination for 60 min, while the ZnO nanoparticles showed only 56% dye degradation under the same condition. Additionally, the degradation rate was enhanced by four times. Furthermore, the catalysts maintained their initial activity with no significant loss after four uses, showing their potential for practical implementation in the mass purification of wastewater.

Biomimetic and bioorthogonal nanozymes for biomedical applications.

Nanozymes mimic the function of enzymes, which drive essential intracellular chemical reactions that govern biological processes. They efficiently generate or degrade specific biomolecules that can initiate or inhibit biological processes, regulating cellular behaviors. Two approaches for utilizing nanozymes in intracellular chemistry have been reported. Biomimetic catalysis replicates the identical reactions of natural enzymes, and bioorthogonal catalysis enables chemistries inaccessible in cells. Various nanozymes based on nanomaterials and catalytic metals are employed to attain intended specific catalysis in cells either to mimic the enzymatic mechanism and kinetics or expand inaccessible chemistries. Each nanozyme approach has its own intrinsic advantages and limitations, making them complementary for diverse and specific applications. This review summarizes the strategies for intracellular catalysis and applications of biomimetic and bioorthogonal nanozymes, including a discussion of their limitations and future research directions.

Enhancement of Gene Editing and Base Editing with Therapeutic Ribonucleoproteins through In Vivo Delivery Based on Absorptive Silica Nanoconstruct.

Key to the widespread and secure application of genome editing tools is the safe and effective delivery of multiple components of ribonucleoproteins (RNPs) into single cells, which remains a biological barrier to their clinical application. To overcome this issue, a robust RNP delivery platform based on a biocompatible sponge-like silica nanoconstruct (SN) for storing and directly delivering therapeutic RNPs, including Cas9 nuclease RNP (Cas9-RNP) and base editor RNP (BE-RNP) is designed. Compared with commercialized material such as lipid-based methods, up to 50-fold gene deletion and 10-fold base substitution efficiency is obtained with a low off-target efficiency by targeting various cells and genes. In particular, gene correction is successfully induced by SN-based delivery through intravenous injection in an in vivo solid-tumor model and through subretinal injection in mouse eye. Moreover, because of its low toxicity and high biodegradability, SN has negligible effect on cellular function of organs. As the engineered SN can overcome practical challenges associated with therapeutic RNP application, it is strongly expected this platform to be a modular RNPs delivery system, facilitating in vivo gene deletion and editing.

Selective Cell-Cell Adhesion Regulation via Cyclic Mechanical Deformation Induced by Ultrafast Nanovibrations.

The adoption of dynamic mechanomodulation to regulate cellular behavior is an alternative to the use of chemical drugs, allowing spatiotemporal control. However, cell-selective targeting of mechanical stimuli is challenging due to the lack of strategies with which to convert macroscopic mechanical movements to different cellular responses. Here, we designed a nanoscale vibrating surface that controls cell behavior via selective repetitive cell deformation based on a poroelastic cell model. The vibrating indentations induce repetitive water redistribution in the cells with water redistribution rates faster than the vibrating rate; however, in the opposite case, cells perceive the vibrations as a one-time stimulus. The selective regulation of cell-cell adhesion through adjusting the frequency of nanovibration was demonstrated by suppression of cadherin expression in smooth muscle cells (fast water redistribution rate) with no change in vascular endothelial cells (slow water redistribution rate). This technique may provide a new strategy for cell-type-specific mechanical stimulation.

Colorimetric protein sensing using catalytically amplified sensor arrays.

Catalytically active iron oxide nanoparticles are used as recognition elements and signal amplifiers for the array-based colorimetric sensing of proteins. Interactions between cationic monolayers on the Fe(3) O(4) NPs and analyte proteins differentially modulates the peroxidase-like activity of Fe(3) O(4) NPs, affording catalytically amplified colorimetric signal patterns that enable the detection and identification of proteins at 50 nM.

Strainer-Separable TiO2 on Halloysite Nanocomposite-Embedded Alginate Capsules with Enhanced Photocatalytic Activity for Degradation of Organic Dyes.

Photocatalysis driven by natural sunlight is an attractive approach to removing pollutants from wastewater. Although TiO2-based photocatalysts using various support nano-materials with high catalytic activity and reusability have been developed for purifying wastewater, the centrifugal separation methods used for the nanocatalysts limit their use for treating large amounts of water. Here, we prepared a TiO2 nano-catalyst supported on a halloysite nanotube (HNT)-encapsulated alginate capsule (TiO2@HNT/Alcap) to recapture the catalysts rapidly without centrifugation. The structure of TiO2@HNT/Alcap was characterized by X-ray diffraction, SEM, and TGA. In our system, the combination of HNTs and alginate capsules (Alcaps) improved the efficiency of adsorption of organic pollutants to TiO2, and their milli = meter scale structure allowed ultra-fast filtering using a strainer. The TiO2@HNT/Alcaps showed ~1.7 times higher adsorption of rhodamine B compared to empty alginate capsules and also showed ~10 and ~6 times higher degradation rate compared to the HNT/Alcaps and TiO2/Alcaps, respectively.

Molecular-scale investigation of tolane disulfide self-assembled monolayers on Au(111) using scanning tunneling microscopy.

Molecular-scale surface structures of self-assembled monolayers (SAMs) formed by the spontaneous adsorption of tolane disulfides (TDS) on Au(111) in a 1 mM mixed solution of ethanol/N, N'-dimethylformamide (9:1) were examined using scanning tunneling microscopy (STM). The STM study revealed that TDS SAMs formed after a 24 h immersion at room temperature were composed of two-dimensional (2D) ordered phases with inhomogeneous surface morphologies and no clear domain boundaries. However, after 2 h immersion at 50 degrees C, uniform 2D ordered domains with clear domain boundaries were observed, which could be described as c(3 x square root of 3) structures with centered rectangular unit cell. Interestingly, a unique intermediate ordered phase with a low surface coverage was also observed. After a longer immersion for 24 h at 50 degrees C, only the uniform c(3 x square root of 3) domains were observed with a corrugation that may have reflected surface reconstruction of the Au(111) surfaces. From this study, we found that 2D ordered TDS SAMs with large and uniform domains on Au(111) can be obtained by controlling the solution temperature and immersion time.

Recognition-mediated assembly of quantum dot polymer conjugates with controlled morphology.

We have demonstrated a polymer mediated "bricks and mortar" method for the self-assembly of quantum dots (QDs). This strategy allows QDs to self-assemble into structured aggregates using complementary three-point hydrogen bonding. The resulting nanocomposites have distinct morphologies and inter-particle distances based on the ratio between QDs and polymer. Time resolved photoluminescence measurements showed that the optical properties of the QDs were retained after self-assembly.

Noninvasive Precision Screening of Prostate Cancer by Urinary Multimarker Sensor and Artificial Intelligence Analysis.

Screening for prostate cancer relies on the serum prostate-specific antigen test, which provides a high rate of false positives (80%). This results in a large number of unnecessary biopsies and subsequent overtreatment. Considering the frequency of the test, there is a critical unmet need of precision screening for prostate cancer. Here, we introduced a urinary multimarker biosensor with a capacity to learn to achieve this goal. The correlation of clinical state with the sensing signals from urinary multimarkers was analyzed by two common machine learning algorithms. As the number of biomarkers was increased, both algorithms provided a monotonic increase in screening performance. Under the best combination of biomarkers, the machine learning algorithms screened prostate cancer patients with more than 99% accuracy using 76 urine specimens. Urinary multimarker biosensor leveraged by machine learning analysis can be an important strategy of precision screening for cancers using a drop of bodily fluid.

Electrical Cartridge Sensor Enables Reliable and Direct Identification of MicroRNAs in Urine of Patients.

Urinary miRNAs are biomarkers that demonstrate considerable promise for the noninvasive diagnosis and prognosis of diseases. However, because of background noise resulting from complex physiological features of urine, instability of miRNAs, and their low concentration, accurate monitoring of miRNAs in urine is challenging. To address these limitations, we developed a urine-based disposable and switchable electrical sensor that enables reliable and direct identification of miRNAs in patient urine. The proposed sensing platform combining disposable sensor chips composed of a reduced graphene oxide nanosheet and peptide nucleic acid facilitates the label-free detection of urinary miRNAs with high specificity and sensitivity. Using real-time detection of miRNAs in patient urine without pretreatment or signal amplification, this sensor allows rapid, direct detection of target miRNAs in a broad dynamic range with a detection limit down to 10 fM in human urine specimens within 20 min and enables simultaneous quantification of multiple miRNAs. As confirmed using a blind comparison with the results of pathological examination of patients with prostate cancer, the sensor offers the potential to improve the accuracy of early diagnosis before a biopsy is taken. This study holds the usefulness of the practical sensor for the clinical diagnosis of urological diseases.

Drug resistance-free cytotoxic nanodrugs in composites for cancer therapy.

Drug resistance is a major cause of treatment failure for small-molecule cancer chemotherapies, despite the advances in combination therapies, drug delivery systems, epigenetic drugs, and proteolysis-targeting chimeras. Herein, we report the use of a drug resistance-free cytotoxic nanodrug as an alternative to small-molecule drugs. The present nanodrugs comprise 2 nm core gold nanoparticles (AuNPs) covered completely with multivalent hydrocarbon chains to a final diameter of ∼10 nm as single drug molecules. This hydrophobic drug-platform was delivered in composite form (∼35 nm) with block-copolymer like other small-molecular drugs. Upon uptake by cells, the nanodrugs enhanced the intracellular levels of reactive oxygen species and induced apoptosis, presumably reflecting multivalent interactions between aliphatic chains and intracellular biomolecules. No resistance to our novel nanodrug was observed following multiple treatment passages and the potential for use in cancer therapy was verified in a breast cancer patient-derived xenograft mouse model. These findings provide insight into the use of nano-scaled compounds as agents that evade drug resistance to cancer therapy.