Navigating the microenvironment with flip and turn under quadrupole magnetophoretic steering control: Nanosphere- and nanorod-coated microbead.

The spatiotemporal accuracy of microscale magnetophoresis has improved significantly over the course of several decades of development. However, most of the studies so far were using magnetic microbead composed of nanosphere particle for magnetophoretic actuation purpose. Here, we developed an in-house method for magnetic sample analysis called quadrupole magnetic steering control (QMSC). QMSC was used to study the magnetophoretic behavior of polystyrene microbeads decorated with iron oxide nanospheres-coated polystyrene microbeads (IONSs-PS) and iron oxide nanorods-coated polystyrene microbeads (IONRs-PS) under the influence of a quadrupole low field gradient. During a 4-s QMSC experiment, the IONSs-PS and IONRs-PS were navigated to perform 180° flip and 90° turn formations, and their kinematic results (2 s before and 2 s after the flip/turn) were measured and compared. The results showed that the IONRs-PS suffered from significant kinematic disproportion, translating a highly uneven amount of kinetic energy from the same magnitude of magnetic control. Combining the kinematic analysis, transmission electron microscopy micrographs, and vibrating sample magnetometry measurements, it was found that the IONRs-PS experienced higher fluid drag force and had lower consistency than the IONSs-PS due to its extensive open fractal nanorod structure on the bead surface and uneven magnetization, which was attributed to its ferrimagnetic nature.

Copper-coordinated nanoassemblies based on photosensitizer-chemo prodrugs and checkpoint inhibitors for enhanced apoptosis-cuproptosis and immunotherapy.

Cuproptosis is a recently identified copper-dependent form of nonapoptotic cell death and holds great prospect in cancer treatment. One of the most intriguing aspects of cuproptosis is its ability to synergize with apoptosis-based cancer treatments. Herein, we presented a novel approach using copper-coordinated nanoassemblies (CCNAs) that were constructed by incorporating a photosensitizer Zinc Phthalocyanine (ZnPc)-chemotherapeutic (DOX) prodrug with a thioketal (TK) spacer and an IDO inhibitor (1-methyl tryptophan, 1-MT) as building blocks for Cu2+-coordination self-assembly to achieve combinational apoptosis-cuproptosis and immunotherapy. Upon NIR laser irradiation, the ZnPc component of CCNAs exhibited a photodynamic effect that generated reactive oxygen species (ROS). This triggered the release of DOX, leading to enhanced tumor cell apoptosis. Additionally, the presence of Cu2+ in the CCNAs not only enhanced the photodynamic process by catalyzing oxygen generation but also promoted the aggregation of toxic mitochondrial proteins, leading to cell cuproptosis. Importantly, the intensified cuproptosis-apoptosis effect triggered an immunogenic cell death (ICD) response. The released 1-MT complemented this response by reversing the immunosuppressive tumor microenvironment (ITM), synergistically amplifying anti-tumor immunity and suppressing the growth of primary and distant tumors. The findings of this study provide a new perspective on potential cancer treatments based on cuproptosis-apoptosis synergistic immunotherapy and stimulate further research in the design of advanced metal-coordinated nanomedicines. STATEMENT OF SIGNIFICANCE: The combination of cuproptosis and apoptosis that act with different mechanisms holds enormous potential in cancer treatment. Here, copper-coordinated nanoassemblies (CCNAs) based on photosensitizer-chemo prodrugs and checkpoint inhibitors were constructed for mediating cuproptosis-apoptosis and subsequently promoting cancer immunotherapy. CCNAs not only promoted the photodynamic effect and activation of chemotherapy through catalyzing the generation of oxygen but also induced toxic mitochondrial protein aggregation, leading to cell cuproptosis. These synergistic antitumor effects triggered robust immune responses with the aid of immune checkpoint blockade, almost eradicating primary tumors and inhibiting distant tumors by around 83 % without systemic toxicity.

Supramolecular catalytic nanomedicines based on coordination self-assembly of amino acids for cascade-activated and -amplified synergetic cancer therapy.

Simple biomolecule-based supramolecular nanomedicines hold great promise in cancer therapy, but their clinical translation is greatly hindered by low tumor-specificity and unsatisfactory antitumor performance. Herein, we developed an amino acid basedsupramolecular nanomedicine that could be co-activated by multiple stimuli in tumor tissue to trigger cascade catalytic reactions in situ for synergetic therapy. The supramolecular nanomedicine was developed based on a combination of coordination and hydrophobic noncovalent interactions among amphiphilic amino acids, glucose oxidase (GOx), copper ions, as well as doxorubicin (DOX)-camptothecin (CPT) prodrugs. The cascade reactions including the catalytic oxidation of glucose to generate H2O2, GSH reducing Cu2+ to Cu+, a Fenton-like reaction between H2O2 and Cu+ to produce hydroxyl radicals (˙OH), and ˙OH-triggered rapid release of dual parent drugs were specifically activated in tumor cells. With these cascade reactions, the catalytic-chemo synergetic therapy was realized for high-efficiency tumor suppression.

Steered polymorphic nanodomains in TiO2 to boost visible-light photocatalytic oxidation.

A breakthrough in enhancing visible-light photocatalysis of wide-bandgap semiconductors such as prototypical titania (TiO2) via cocatalyst decoration is still challenged by insufficient heterojunctions and inevitable interfacial transport issues. Herein, we report a novel TiO2-based composite material composed of in situ generated polymorphic nanodomains including carbon nitride (C3N4) and (001)/(101)-faceted anatase nanocrystals. The introduction of ultrafine C3N4 results in the generation of many oxygen vacancies in the TiO2 lattice, and simultaneously induces the exposure and growth of anatase TiO2(001) facets with high surface energy. The photocatalytic performance of C3N4-induced TiO2 for degradation of 2,4-dichlorophenol under visible-light irradiation was tested, its apparent rate being up to 1.49 × 10-2 min-1, almost 3.8 times as high as that for the pure TiO2 nanofibers. More significantly, even under low operation temperature and after a long-term photocatalytic process, the composite still exhibits exceptional degradation efficiency and stability. The normalized degradation efficiency and effective lifespan of the composite photocatalyst are far superior to other reported modified photocatalysts.

Differential induction of antioxidant and anti-inflammatory phytochemicals in agitated micro-shoot cultures of Ajuga integrifolia Buch. Ham. ex D.Don with biotic elicitors.

Ajuga integrifolia Buch. Ham. ex D.Don, a member of Lamiaceae family is pharmaceutically an active perennial herb widely spread in China, Afghanistan and Pakistan Himalayan region. The application of biotic elicitors is a promising approach to cover limitations of in vitro cell technology and challenges faced by pharmaceuticals industry for bulk up production. The current study involved the induction of agitated micro-shoot cultures with the aim to investigate the growth-promoting as well as phytochemicals enhancement role of yeast extract (YE) and pectin (PE). The results showed that both elicitors induced a considerable physiological response. Biomass accumulation was observed maximum (DW: 18.3 g/L) against PE (10 mg/L) compared to YE and control. Eleven secondary phytocompounds were quantified using high-performance liquid chromatography. PE (50 mg/L) was found to be effective in elicitation of rosmarinic acid (680.20 µg/g), chlorogenic acid (294.12 µg/g), apigenin (579.61 µg/g) and quercetin (596.89 µg/g). However, maximum caffeic acid (359.52 µg/g) and luteolin (546.12 µg/g accumulation was noted in PE (1 mg/L) treatment. Harpagide, aucubin, harpagoside and 8-O-acetyl-harpagoside production was suppressed by both elicitors except for YE (100 mg/L). Catalpol accumulation in micro-shoot cultures was also downregulated except in response to YE (50 and 100 mg/L). Antioxidant activity and anti-inflammatory activity remained higher under PE (50 mg/L) and YE (100 mg/L) respectively. Therefore, results suggested that Ajuga integrifolia micro-shoot cultures treated with yeast extract and pectin might be an efficient bio-factory to produce commercially potent specific secondary metabolites.

The Transport Behavior of a Biflagellated Microswimmer before and after Cargo Loading.

The changes in the transport behavior of a microswimmer before and after cargo loading are crucial to understanding and control of the motion of a biohybrid microbot. In this work, we show the change in swimming behavior of biflagellated microalgae Chlamydomonas reinhardtii picking up a 4.5 µm polystyrene microbead upon collision. The microswimmer changed from linear forward motion into helical motion upon the attachment of the cargo and swam with a decreased swimming velocity. We revealed the helical motion of the microswimmer upon cargo loading due to suppression of flagella by image analysis of magnified time-lapse images of C. reinhardtii with one microbead attached at the anterior end (between the flagella). Furthered suppression on the flagellum imposed by the loading of the second cargo has led to increased oscillation per displacement traveled and decreased swimming velocity. Moreover, the microswimmer with a microbead attached at the posterior end swam with swimming velocity close to free swimming microalgae and did not exhibit helical swimming behavior. The experimental results and analysis showed that the loading location of the cargo has a great influence over the swimming behavior of the microswimmer. Furthermore, the work balance calculation and mathematical analysis based on Lighthill's model are well consistent with our experimental findings.

Efficient phenol degradation by laccase immobilized on functional magnetic nanoparticles in fixed bed reactor under high-gradient magnetic field.

Enzymatic degradation of emerging contaminants has gained great interest for the past few years. However, free enzyme often incurs high costs in practice. The immobilized laccase on the polyethylenimine (PEI)-functionalized magnetic nanoparticles (Fe3O4-NH2-PEI-laccase) was fabricated to efficiently degrade phenolic compounds continuously in a newly fixed bed reactor under a high-gradient magnetic field. The degradation rate of continuous treatment in the bed after 18 h was 2.38 times as high as that of batch treatment after six successive operations with the same treatment duration. Under the optimal conditions of volume fraction of nickel wires mesh, flow rate of phenol solution, phenol concentration, and Fe3O4-NH2-PEI-laccase amount, the degradation rate of phenol kept over 70.30% in 48 h continuous treatment. The fixed bed reactor filled with Fe3O4-NH2-PEI-laccase provided a promising avenue for the continuous biodegradation of phenolic compounds for industrial wastewater in practice.

An amino acid-based supramolecular nanozyme by coordination self-assembly for cascade catalysis and enhanced chemodynamic therapy towards biomedical applications.

The clinical translation of chemodynamic therapy has been highly obstructed by the insufficient intracellular H2O2 level in diseased tissues. Herein, we developed a supramolecular nanozyme through a facile one-step cooperative coordination self-assembly of an amphipathic amino acid and glucose oxidase (GOx) in the presence of Fe2+. The results demonstrated that the supramolecular nanozyme possessed cascade enzymatic activity (i.e., GOx and peroxidase), which could amplify the killing efficacy of hydroxyl radicals (˙OH) via self-supplying H2O2, finally achieving synergistic starvation-chemodynamic cancer therapy in vitro. Additionally, this cascade nanozyme also exhibited highly effective antibacterial activity on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) without the need for additional H2O2. This work provided a promising strategy for the design and development of nanozymes for future biomedical applications.

A Review of Microbial Mediated Iron Nanoparticles (IONPs) and Its Biomedical Applications.

Nanotechnology is a booming avenue in science and has a multitude of applications in health, agriculture, and industry. It exploits materials' size at nanoscale (1-100 nm) known as nanoparticles (NPs). These nanoscale constituents are made via chemical, physical, and biological methods; however, the biological approach offers multiple benefits over the other counterparts. This method utilizes various biological resources for synthesis (microbes, plants, and others), which act as a reducing and capping agent. Among these sources, microbes provide an excellent platform for synthesis and have been recently exploited in the synthesis of various metallic NPs, in particular iron. Owing to their biocompatible nature, superparamagnetic properties, small size efficient, permeability, and absorption, they have become an integral part of biomedical research. This review focuses on microbial synthesis of iron oxide nanoparticles using various species of bacteria, fungi, and yeast. Possible applications and challenges that need to be addressed have also been discussed in the review; in particular, their antimicrobial and anticancer potentials are discussed in detail along with possible mechanisms. Moreover, some other possible biomedical applications are also highlighted. Although iron oxide nanoparticles have revolutionized biomedical research, issues such as cytotoxicity and biodegradability are still a major bottleneck in the commercialization of these nanoparticle-based products. Addressing these issues should be the topmost priority so that the biomedical industry can reap maximum benefit from iron oxide nanoparticle-based products.

Liver toxicity of macrolide antibiotics in zebrafish.

Macrolide antibiotics (macrolides) are among the most commonly prescribed antibiotics worldwide and are used for a wide range of infections, but macrolides also expose people to the risk of adverse events include hepatotoxicity. Here, we report the liver toxicity of macrolides with different structures in zebrafish. The absorption, distribution, metabolism, excretion and toxicology (ADMET) parameters of macrolide compounds were predicted and contrasted by utilizing in silico analysis. Fluorescence imaging and Oil Red O stain assays showed all the tested macrolide drugs induced liver degeneration, changed liver size and liver steatosis in larval zebrafish. Through RNA-seq analysis, we found seven co-regulated differentially expressed genes (co-DEGs) associated with metabolism, apoptosis and immune system biological processes, and two co-regulated significant pathways including amino sugar and nucleotide sugar metabolism and apoptosis signaling pathway. We found that only fosab of seven co-DEGs was in the two co-regulated significant pathways. fosab encoded proto-oncogene c-Fos, which was closely associated with liver diseases. The whole-mount in situ hybridization showed high transcription of c-Fos induced by macrolide compounds mainly in the liver region of zebrafish larvae. Cell Counting Kit-8 (CCK-8) and lactate dehydrogenase (LDH) leakage assays revealed that macrolides exerts significant cytotoxic effects on L02 cells. qRT-PCR and western blot analysis demonstrated macrolides also promoted human c-Fos expression in L02 cells. The c-Fos overexpression significantly reduced cell viability by using CCK-8 assay. These data indicate that hepatotoxicity induced by macrolides may be correlated with c-Fos expression activated by these compounds. This study may provide a biomarker for the further investigations on the mechanism of hepatotoxicity induced by macrolide drugs with different structures, and extend our understanding for improving rational clinical application of macrolides.

Research advances of DNA aptasensors for foodborne pathogen detection.

Aptamers, referring to single-stranded DNA or RNA molecules can specifically recognize and bind to their targets. Based on their excellent specificity, sensitivity, high affinity, and simplicity of modification, aptamers offer great potential for pathogen detection and biomolecular screening. This article reviews aptamer screening technologies and aptamer application technologies, including gold-nanoparticle lateral flow assays, fluorescence assays, electrochemical assays, colorimetric assays, and surface-enhanced Raman assays, in the detection of foodborne pathogens. Although notable progress (more rapid, sensitive, and accurate) has been achieved in the field, challenges and drawbacks in their applications still remain to be overcome.

Direct Current-Powered High-Performance Ionic Hydrogel Strain Sensor Based on Electrochemical Redox Reaction.

Ionic hydrogel-based resistance strain sensors (IRS-sensors) powered by direct current (dc) enable various wearable applications. However, the unclear signal transmission mechanism causes significant difficulty to solve the problem of their weak detection ability for subtle strain changes. Here, we have conducted a combined theoretical and experimental study to demonstrate that the signal transmission of dc-powered IRS-sensors is determined by the electrochemical redox process. The slow H+ reduction rate and chemical component change within the hydrogel account for their low sensitivity and signal-to-noise ratio (SNR). To address such a challenge, we have introduced Cu2+ into the hydrogels to enhance the cathodic reduction rate and the chemical stability of the IRS-sensors. The as-prepared IRS-sensors show high sensitivity, ultrahigh SNR, and excellent sensing reliability. Besides the inherent ultrawide sensing range (>1500%), the IRS-sensor can also provide recognizable electrical responses to the incredibly small strain (0.005%), which is 2 orders of magnitude lower than previous ones. They demonstrate precise and reliable monitoring for full-range human activities. This new strategy can be easily extended to other ionic hydrogels and electrodes as well as self-driving electrochemical electrodes for the fabrication of various high-performance self-powered IRS-sensors.

Ultrasensitive strips for the quadruple detection of nitrofuran metabolite residues.

In this biosensor system, metabolite residues were derived by using a previous B-CBA synthesis method to label a biotin moiety for enrichment by streptavidin coated magnetic beads. Antibodies specific for derivatives were conjugated with carboxyl-modified barcode DNAs which were used as templates for strand displacement amplification (SDA). The assay can detect trace levels of 7.20 ppt of SEM, 11.58 ppt of AHD, 7.24 ppt of AOZ and 2.31 ppt of AMOZ, respectively.

Effects of incident light intensity and light path length on cell growth and oil accumulation in Botryococcus braunii (Chlorophyta).

Botryococcus braunii was cultured in different light path length under different incident light intensity to investigate the effect of light on alga growth as well as hydrocarbon and fatty acid accumulation. Results indicated that longer light path length required higher incident light intensity in order to meet the light requirement of algal growth and hydrocarbon accumulation during the course of cultivation. However, hydrocarbon profile was only affected by the incident light intensity and not influenced by the light path length. High incident light intensity enhanced the accumulation of hydrocarbons with longer carbon chains. Besides, the fatty acid content and profiles were significantly influenced by both incident light intensity and light path. Higher fatty acid content and higher percentage of C18 and monounsaturated fatty acid components were achieved at the higher incident light intensity and lower light path length. Taken together, these results are benefit to improve its biomass and oil productivity through the optimization of light and photobioreactor design.

Farnesol-induced hyperbranched morphology with short hyphae and bulbous tips of Coriolus versicolor.

As the first fungal quorum sensing molecule, farnesol-induced morphological transition is usually studied in dimorphic fungi, but in basidiomycetes the morphological changes regulated by farnesol are rarely investigated. In this study, we found that farnesol made the basidiomycete Coriolus versicolor develop into a hyperbranched morphology with short hyphae and bulbous tips. Farnesol treatment resulted in a significant increase of intracellular oxidative stress level, which influenced the expression of several morphogenesis-related genes, and thereby led to the morphological changes. High oxidative stress level significantly stimulated the expression of laccase genes for improving intracellular laccase biosynthesis. The resulted hyperbranched morphology further accelerated the secretion of intracellular laccase into culture medium. As a result, extracellular laccase production reached a maximum of 2189.2 ± 54.7 U/L in farnesol-induced cultures, which was 6.8-fold greater than that of control cultures. SDS-PAGE and native-PAGE showed that farnesol increased laccase production by promoting the biosynthesis of three laccase isoforms. Together these results provide new opportunities in not only understanding the farnesol-regulated mycelial morphology in basidiomycetes, but also developing novel strategies for enhancing the production of secreted enzymes of biotechnological interest.

Artificial Magnetotaxis of Microbot: Magnetophoresis versus Self-Swimming.

An artificial magnetotactic microbot was created by integrating the microalgal cell with magnetic microbead for its potential application as biomotor in microscale environment. Here, we demonstrate the remote magnetotactic control of the microbot under a low gradient magnetic field (<100 T/m). We characterize the kinematic behavior of the microbots carrying magnetic microbeads of two different sizes, with diameter of 2 and 4.5 µm, in the absence and presence of magnetic field. In the absence of magnetic field, we observed the microbot showed a helical motion as a result of the misalignment between the thrust force and the symmetry axis after the attachment. The microbot bound with a larger magnetic microbead moved with higher translational velocity but rotated slower about its axis of rotation. The viscous force was balanced by the thrust force of the microbot, resulting in a randomized swimming behavior of the microbot at its terminal velocity. Meanwhile, under the influence of a low gradient magnetic field, we demonstrated that the directional control of the microbot was based on following principles: (1) magnetophoretic force was insignificant on influencing its perpendicular motion and (2) its parallel motion was dependent on both self-swimming and magnetophoresis, in which this cooperative effect was a function of separation distance from the magnet. As the microbot approached the magnet, the magnetophoretic force suppressed its self-swimming behavior, leading to a positive magnetotaxis of the microbot toward the source of magnetic field. Our experimental results and kinematic analysis revealed the contribution of mass density variation of particle-and-cell system on influencing its dynamical behavior.

Efficient Catalytic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid by Magnetic Laccase Catalyst.

2,5-Furandicarboxylic acid (FDCA) is a bio-based platform chemical for the production of polyethylene furanoate (PEF) and other valuable furanic chemicals. A magnetic laccase catalyst with (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (TEMPO) as the mediator has the remarkable capability of oxidizing 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). Under optimal reaction conditions, a quantitative yield (90.2 %) of FDCA with complete HMF conversion was obtained after 96 h of reaction. More importantly, the magnetic laccase catalyst exhibited good recyclability and stability, maintaining 84.8 % of its original activity following six reuse cycles. This is the first report on the efficient catalytic oxidation of HMF to FDCA by using an immobilized enzyme catalyst.

Quorum sensing molecule-farnesol increased the production and biological activities of extracellular polysaccharide from Trametes versicolor.

A novel strategy of exposing 2-day-old mycelia cultures to 0.8mM farnesol was developed to stimulate extracellular polysaccharide (EPS) production in Trametes versicolor submerged cultures. Farnesol, a quorum sensing molecule in fungi, could significantly increase EPS production by promoting polysaccharide biosynthesis and regulating mycelial morphology. EPS yield reached a maximum of 2.56g/L that was 2.7-fold greater than that of control cultures. Farnesol made T. versicolor develop into fluffy, loose and multi-hyphae morphology, which facilitated the excretion of intracellular polysaccharide into culture medium. Moreover, EPS from farnesol-induced cultures (EPS-F) with higher carbohydrate and uronic acid contents mainly contained high molecular weight polysaccharide (134kDa, 85%), and comprised glucose, mannose and galactose in a molar ratio of 34.2:2.1:1.0. These physicochemical properties led to stronger antioxidant and antitumor activities of EPS-F. This is the first report that farnesol can significantly improve the production of polysaccharide with higher biological activities. It provides a novel strategy to enhance the production and bioactivity of mushroom polysaccharide using microbial quorum sensing molecules.

Scale-up laccase production from Trametes versicolor stimulated by vanillic acid.

An efficient strategy for laccase production in Trametes versicolor cultures was developed using vanillic acid as the inducer. The optimized vanillic acid treatment strategy consisted of exposing 2-day-old mycelia cultures to 80 mg/L vanillic acid. After 4 days, laccase activity of 588.84 U/L was achieved in flasks which represented a 1.79-fold increase compared to the control. In 200-L airlift bioreactor, the maximal laccase activity reached up to 785.12 U/L using the optimized vanillic acid treatment strategy. The zymograms of culture supernatants revealed three bands with laccase activity, among which Lac1 and Lac2 were abundant laccase isoforms constitutively expressed, and Lac3 was an inducible isozyme by vanillic acid. The results of real-time quantitative PCR showed that the transcription level of lcc in T. versicolor cultures grown with vanillic acid for 7 days was about 5.64-fold greater than that without vanillic acid in flasks. In 200-L airlift bioreactor cultures of T. versicolor with addition of vanillic acid, the transcript level of lcc at day 7 was 2.62-fold higher than that in flasks with vanillic acid due to the good mass transfer and oxygen supply in the bioreactor system. This study provides a basis for understanding the induction mechanism of vanillic acid for laccase production and has good potential for industrial applications.

Chitosan multiple addition enhances laccase production from Trametes versicolor.

Chitosan multiple addition strategy was developed to improve laccase production from Trametes versicolor cultures. The optimized multiple addition strategy was carried out by two-time addition of 0.1 g L(-1) chitosan to a 2-day-old culture media, with 24-h interval between the treatments. Under these conditions, laccase activity of 644.9 U l(-1) was achieved on the seventh day and laccase production was improved by 93.5 % higher than the control. Chitosan treatment increased reactive oxygen species generation and extracellular protein concentration in the treated mycelia. In contrast, the inducer inhibited the mycelia growth. The result of the quantitative reverse transcription polymerase chain reaction showed that the copy number of the laccase gene transcript increased by 16.7-fold in the treated mycelia relative to the control. This study provides insight into some of the intrinsic metabolic processes involved in the upregulation of laccase production in the presence of chitosan inducer in fungal culture.