Excitation/emission-enhanced heterostructure photonic crystal array synergizing with "DD-A" FRET entropy-driven circuit for high-resolution and ultrasensitive analysis of ctDNA.

Circulating tumor DNA (ctDNA) is an emerging biomarker of liquid biopsy for cancer. But it remains a challenge to achieve simple, sensitive and specific detection of ctDNA because of low abundance and single-base mutation. In this work, an excitation/emission-enhanced heterostructure photonic crystal (PC) array synergizing with entropy-driven circuit (EDC) was developed for high-resolution and ultrasensitive analysis of ctDNA. The donor donor-acceptor FÖrster resonance energy transfer ("DD-A" FRET) was integrated in EDC based on the introduction of simple auxiliary strand, which exhibited higher sensitivity than that of traditional EDC. The heterostructure PC array was constructed with the bilayer periodic nanostructures of nanospheres. Because the heterostructure PC has the adjustable dual photonic band gaps (PBGs) by changing nanosphere sizes, and the "DD-A" FRET can offer the excitation and emission peak with enough distance, it helps the successful matches between the dual PBGs of heterostructure PC and the excitation/emission peaks of "DD-A" FRET; thus, the fluorescence from EDC can be enhanced effectively from both of excitation and emission processes on heterostructure PC array. Besides, high-resolution of single-base mutation was obtained through the strict recognition of EDC. Benefiting from the specific spectrum-matched and synergetic amplification of heterostructure PC and EDC with "DD-A" FRET, the proposed array obtained ultrasensitive detection of ctDNA with LOD of 12.9 fM, and achieved the analysis of mutation frequency as low as 0.01%. Therefore, the proposed strategy has the advantages of simple operation, mild conditions (enzyme-free and isothermal), high-sensitivity, high-resolution and high-throughput analysis, showing potential in bioassay and clinical application.

Simultaneous detection of two subtypes of extracellular vesicles using ultrabright fluorescent nanosphere-based test strips.

In recent years, the cargo profiles of extracellular vesicles (EVs), which were inherited from their parent cells, have emerged as a reliable biomarker for liquid biopsy (LB) in disease diagnosis, prognosis, and treatment monitoring. EVs secreted by different cells exhibit distinct characteristics, particularly in terms of disease diagnosis and prediction. However, currently available techniques for the quantitative analysis of EV cargoes, including enzyme-linked immunosorbent assay (ELISA), cannot specifically identify the cellular origin of EVs, thus seriously affecting the accuracy of EV-based liquid biopsy. In light of this, we here developed ultrabright fluorescent nanosphere (FNs)-based test strips which have the unique capability to specifically assess the levels of PD-L1-positive EVs (PD-L1+ EVs) derived from both tumor cells and immune cells in bodily fluids. The levels of PD-L1+ EV subpopulations in human saliva were quantified using the ultrabright fluorescent nanosphere-based test strips with more convenience and higher efficiency (detection time <30 min). Results demonstrated that the fluorescence intensity of the test line exhibited a good linear relationship respectively with the PD-L1 levels of tumor cell- (R2 = 0.993) and immune cell-derived EVs (R2 = 0.982) in human saliva. By assessing the levels of PD-L1+ EV subpopulations, our test strips hold immense potential for advancing the application of PD-L1+ EV subpopulation-based predictions in tumor diagnosis and prognosis evaluation. In summary, by integrating the benefits of FNs and lateral flow chromatography, we here provide a strategy to accurately measure the cargo levels of EVs originating from diverse cell sources in bodily fluids.

Bioactive chitosan/polydopamine nanospheres coating on carbon fiber towards strengthening epoxy composites.

This paper initially examines the feasibility and effectiveness on interfacial adhesion of composites when grafting nanoparticle-structured polydopamine (PDA) and chitosan around carbon fiber periphery. The resulting interfacial shear strength was maximized as 92.3 MPa, delivering 50.1 % and 15.7-16.2 % gains over those of control fiber and only polydopamine nanospheres (PDANPs) or only chitosan modified fiber composites. Measuring surface morphology and thermal stability of fibers found that abundant PDANPs well adhered with the help of chitosan, highlighting nanoscale size effects and intrinsic adhesiveness of PDA. Under good wettability, rich and dense interfacial interactions (covalent and hydrogen bond, electrostatic interaction, and π conjugation) caused by PDANPs/chitosan coating provides impetus for effective stress transfer. Additionally, the stable "soft-rigid" combination of chitosan and PDANPs adds the efficiency of crack passivation. As such, it is hoped that this work could fully explore the possibility of PDA geometry in interphase engineering of fiber composites.

Multi-functional nanozyme-based colorimetric, fluorescence dual-mode assay for Salmonella typhimurium detection in milk.

Rapid and high-sensitive Salmonella detection in milk is important for preventing foodborne disease eruption. To overcome the influence of the complex ingredients in milk on the sensitive detection of Salmonella, a dual-signal reporter red fluorescence nanosphere (RNs)-Pt was designed by combining RNs and Pt nanoparticles. After being equipped with antibodies, the immune RNs-Pt (IRNs-Pt) provide an ultra-strong fluorescence signal when excited by UV light. With the assistance of the H2O2/TMB system, a visible color change appeared that was attributed to the strong peroxidase-like catalytic activity derived from Pt nanoparticles. The IRNs-Pt in conjunction with immune magnetic beads can realize that Salmonella typhimurium (S. typhi) was captured, labeled, and separated effectively from untreated reduced-fat pure milk samples. Under the optimal experimental conditions, with the assay, as low as 50 CFU S. typhi can be converted to detectable fluorescence and absorbance signals within 2 h, suggesting the feasibility of practical application of the assay. Meanwhile, dual-signal modes of quantitative detection were realized. For fluorescence signal detection (emission at 615 nm), the linear correlation between signal intensity and the concentration of S. typhi was Y = 83C-3321 (R2 = 0.9941), ranging from 103 to 105 CFU/mL, while for colorimetric detection (absorbamce at 450 nm), the relationship between signal intensity and the concentration of S. typhi was Y = 2.9logC-10.2 (R2 = 0.9875), ranging from 5 × 103 to 105 CFU/mL. For suspect food contamination by foodborne pathogens, this dual-mode signal readout assay is promising for achieving the aim of convenient preliminary screening and accurate quantification simultaneously.

Measurements of Spontaneous and External Stimuli Molecular Release Processes from a Single Optically Trapped Poly(lactic-co-glycolic) Acid Microparticle and a Liposome Containing Gold Nanospheres.

We investigated the single particle kinetics of the molecular release processes from two types of microcapsules used as drug delivery systems (DDS): biodegradable poly(lactic-co-glycolic) acid (PLGA) and a light-triggered-degradable liposome encapsulating gold nanospheres (liposome-GNP). To optimize the design of DDS capsules, it is highly desirable to develop a method for real-time monitoring of the release process. Using a combination of optical tweezers and confocal fluorescence microspectroscopy we successfully analyzed a single optically trapped PLGA particle and liposome-GNPs in solution. From temporal decay profiles of the fluorescence intensity, we determined the time constant τ of the release processes. We demonstrated that the release rate of spontaneously degradable microcapsules (PLGA) decreased with increasing size, while conversely, the release rate of external stimuli-degradable microcapsules (liposome-GNPs) increased in proportion to their size. This result is explained by the differences in the disruption mechanisms of the capsules, with PLGA undergoing hydrolysis and the GNPs in the liposome-GNP undergoing a photoacoustic effect under nanosecond pulsed laser irradiation. The present approach offers a way forward to an alternative microanalysis system for single drug delivery nanocarriers.

CeO2 nanospheres incorporated with Bi2MoO6/g-C3N4 enhanced photocatalysis towards environmental pollutant Rhodamine B removal.

We have adopted a novel CeO2/Bi2MoO6/g-C3N4-based ternary nanocomposite that was synthesized via hydrothermal technique. The physiochemical characterization of as-prepared samples was examined through various analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy TEM, photoluminescent spectra (PL), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and ultraviolet diffuse reflectance spectroscopy (UV-DRS) technique. In addition, the photocatalytic performance was carried out by degradation of Rhodamine B dye under visible light irradiation using this nanocatalyst. The ternary nanocomposite achieved 94% of the degradation efficiency within 100 min which is higher than the pristine and binary composites under the predetermined condition pH = 7, Rhodamine B dye = 5 mg/L, and catalyst concentration = 150 mg/L. The experimental synergetic effect of CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite has been ascribed to the interfacial charge carrier migration between CeO2, Bi2MoO6, and g-C3N4. The optical absorption range of CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite was enhanced, and the band gap was reduced up to 2.2 eV. In addition, scavenger trapping experiment proves that the super oxide anions (O2-.) and photogenerated holes are the major active species. The reusability and stability experiment proved the CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite keeps good durability during the photocatalytic degradation process after the five successive cycles. Furthermore, based on the results, the charge carrier transfer photocatalytic mechanism was also discussed. This CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite may offer the cheapest material and extend the great opportunity for clean and environmental remediation approach under the visible light irradiation.

Sub-femtomolar vertical graphene field effect immunosensor for detection of lung tumor markers.

Lung cancer is the main cancer that endangers human life worldwide, with the highest mortality rate. The detection of lung tumor markers is of great significance for the early diagnosis and subsequent treatment of lung cancer. In this study, a vertical graphene field effect transistor (VGFET) immunosensor based on graphene/C60 heterojunction was created to offer quantitative detections for the lung tumor markers carcinoembryonic antigen (CEA), cytokeratin 19 fragment (Cyfra21-1), and neuron-specific enolase (NSE). The experimental results showed that the sensitive range for standard antigen is between 1 pg/ml to 100 ng/ml, with a limit of detection (LOD) of 5.6 amol/ml for CEA, 33.3 amol/ml for Cyfra 21-1 and 12.8 amol/ml for NSE (1 pg/ml for all). The detection accuracy for these tumor markers was compared with the clinically used method for clinical patients on serum samples. Results are highly consistent with clinically used immunoassay in its efficient diagnosis concentration range. Subsequently, the mesoporous silica nanospheres (MSNs) with an average size of 90 nm were surface modified with glutaraldehyde, and a second antibody was assembled on MSNs, which fixes nanospheres on the antigen and amplified the field effect. The LODs for three markers are 100 fg/ml (0.56 amol/ml for CEA) under optimal circumstances of detection. This result indicates that specific binding to MSNs enhances local field effects and can achieve higher sensing efficiency for tumor marker detection at extremely low concentrations, providing effective assistance for the early diagnosis of lung cancer.

A covalent-organic framework-based platform for simultaneous smartphone detection and degradation of aflatoxin B1.

This study developed a smartphone-based biosensor that could simultaneously detect and degrade aflatoxin B1 (AFB1). A donor-acceptor covalent organic framework (COF) was bound onto the surface of stainless-steel mesh (SSM) via the in-situ synthesis, which was used to immobilize the aptamer (Apt) to specifically capture AFB1 and was also as a photocatalyst to degrade AFB1. Au@Ir nanospheres were synthesized, which exhibited better peroxidase catalytic activity (Km=5.36 × 10-6 M, Vmax=3.48 × 10-7 Ms-1, Kcat=1.00 × 107 s-1) than Ir@Au nanospheres, so Au@Ir nanospheres were linked with Apt2 to be utilized as the signal probe. The density functional theory calculation also described that Au@Ir nanospheres possessed the lower energy barriers to decompose H2O2 than Ir@Au nanospheres. Coupled with the "Color Picker" application in the smartphone, the established "sandwich-structure" colorimetric method exhibited a linear range of 0.5-200 µg L-1 and a detection limit of 0.045 µg L-1. The photocatalytic capacity of SSM/COF towards AFB1 was investigated and the degradation rate researched 81.14 % within 120 min under the xenon lamp irradiation, and the degradation products were validated by ESI-MS. It was applied for the detection of AFB1 in peanuts, corn, and wheat samples. Recoveries were ranging from 77.90 % to 112.5 %, and the matrix effect was 75.10-111.6 %. Therefore, the smartphone-based biosensor provided a simple, fast, and sensitive platform for the detection of AFB1, and meanwhile could realize the efficient degradation of AFB1.

Potent anti-inflammatory and anti-apoptotic activities of electrostatically complexed C-peptide nanospheres ameliorate diabetic nephropathy.

In the present era of "Diabetic Pandemic", peptide-based therapies have generated immense interest however, are facing odds due to inevitable limitations like stability, delivery complications and off-target effects. One such promising molecule is C-peptide (CPep, 31 amino acid polypeptide with t1/2 30 min); it is a cleaved subunit of pro-insulin, well known to suppress microvascular complications in kidney but has not been able to undergo translation to the clinic till date. Herein, a polymeric CPep nano-complexes (NPX) was prepared by leveraging electrostatic interaction between in-house synthesized cationic, polyethylene carbonate (PEC) based copolymer (Mol. wt. 44,767 Da) and negatively charged CPep (Mol. wt. 3299 Da) at pH 7.4 and further evaluated in vitro and in vivo. NPX exhibited a spherical morphology with a particle size of 167 nm and zeta potential equivalent to +10.3, with 85.70 % of CPep complexation efficiency. The cellular uptake of FITC-tagged CPep NPX was 95.61 % in normal rat kidney cells, NRK-52E. Additionally, the hemocompatible NPX showed prominent cell-proliferative, anti-oxidative (1.8 folds increased GSH; 2.8 folds reduced nitrite concentration) and anti-inflammatory activity in metabolic stress induced NRK-52E cells as well. The observation was further confirmed by upregulation of anti-apoptotic protein BCl2 by 3.5 folds, and proliferative markers (ß1-integrin and EGFR) by 3.5 and 2.3 folds, respectively, compared to the high glucose treated control group. Pharmacokinetic study of NPX in Wistar rats revealed a 6.34 folds greater half-life than free CPep. In in-vivo efficacy study in STZ-induced diabetic nephropathy animal model, NPX reduced blood glucose levels and IL-6 levels significantly by 1.3 and 2.5 folds, respectively, as compared to the disease control group. The above findings suggested that NPX has tremendous potential to impart sustained release of CPep, resulting in enhanced efficacy to treat diabetes-induced nephropathy and significantly improved renal pathology.

Development of a highly sensitive ultra-small ratiometric fluorescence nanosphere probe for Sunset Yellow detection.

A highly sensitive ultra-small ratiometric fluorescence nanosphere probe was successfully manufactured to detect Sunset Yellow (SY). The probe, CMCS@N, S-CDs/Rh6G, was formed through the encapsulation of N, S-CDs and Rh6G within carboxymethyl chitosan (CMCS) through in situ cross-linking. Remarkably, our nanosphere probe had an average grain diameter of 6.80 nm and exhibited excellent dispersibility without the need for additional solvents. The probe exhibited a strong linear relationship with SY concentration in the range of 0.26-100 µM, with a low detection limit of 0.078 µM. Furthermore, SY demonstrated strong fluorescence quenching capability on our nanosphere probe, with the fluorescence quenching mechanism involving a combined effects of inner filter effect (IFE) and static quenching. Notably, our nanosphere probe retained the bacteriostatic properties of CMCS, with a substantial bacteriostasis rate of 77.58 %, introducing novel potential applications.

Plasmon resonances of GZO core-Ag shell nanospheres, nanorods, and nanodisks for biosensing and biomedical applications in near-infrared biological windows I and II.

There is currently a great deal of interest in realizing localized surface plasmon resonances (LSPRs) in two distinct windows in the near-infrared (NIR) spectrum for in vivo biosensing and medical applications, the biological window (BW) I and II (BW I, 700-900 nm; BW II, 1000-1700 nm). This study aims to demonstrate that LSPRs of Ga-doped ZnO (GZO) core-silver (Ag) shell structures exhibit promising features for biological applications in the NIR BW I and II. Here, we study three different shapes for nanoshells: the core-shell nanosphere, nanorod, and nanodisk. In the calculation of the optical response of these nanoshells, an effective medium approach is first used to reduce the dielectric function of a nanoshell to that of an equivalent homogenous NP with an effective dielectric function. Then, the LSPR spectra of nanoshells are calculated using the modified long-wavelength approximation (MLWA), which corrects the polarizability of the equivalent NP as obtained by Gans theory. Through numerical investigations, we examine the impacts of the core and shell sizes of the proposed nanoshells as well as the medium refractive index on the position and line width of the plasmon resonance peaks. It is shown that the plasmon resonances of the three proposed nanoshells exhibit astonishing resonance tunability in the NIR region by varying their geometrical parameters. Specifically, the improved spectrum characteristics and tunability of its plasmon resonances make the GZO-Ag nanosphere a more viable platform for NIR applications than the spherical metal colloid. Furthermore, we demonstrate that the sensitivity and figure of merit (FOM) of the plasmon resonances may be significantly increased by using GZO-Ag nanorods and nanodisks in place of GZO-Ag nanospheres. It is found that the optical properties of the transverse plasmon resonance of the GZO-Ag nanodisk are superior to all plasmon resonances produced by the GZO-Ag nanorods and GZO-Ag nanospheres in terms of sensitivity and FOM. The FOM of the transverse plasmon mode of the GZO-Ag nanodisk is almost two orders of magnitude higher than that of the longitudinal and transverse plasmon modes of the GZO-Ag nanorod in BW I and BW II. And it is 1.5 and 2 times higher than the plasmon resonance FOM of GZO-Ag nanospheres in BW I and BW II, respectively.

Neodymium niobate nanospheres on functionalized carbon nanofibers: a nanoengineering approach for highly sensitive vanillin detection.

Vanillin (VAN), the primary aroma compound in vanilla, contributes significantly to sensory delight; however, its unrestrained presence poses notable health risks. In response to the demanding concern regarding food safety, researchers have directed their efforts towards the detection of VAN, seeking sustainable strategies for contamination prevention. A groundbreaking solution has emerged in the form of a novel sensing platform, whose core lies on a finely tuned electrode, crafted through the incorporation of nano-sized NdNbO4 spheres onto carbon nanofibers (CNFs). This incorporation serves to augment the capabilities of a glassy carbon electrode (GCE), transforming it into a highly sensitive detector primed for vanillin detection. The NdNbO4/f-CNF nanocomposite embodies a paradigm of synergistic collaboration, wherein the nonlinear cumulative effects of synergism and quantum confinement impart exceptional performance characteristics. Notably, the sensor achieves a low detection limit of 6.3 nmol L-1, indicative of its remarkable sensitivity of 2.3 µA µ(mol L-1)-1 cm-2 and precision of 1.519 and 4.72%. Moreover, the sensor boasts a wide linear range spanning from 0.001 to 63.101 µmol L-1. These attributes, coupled with its discerning selectivity and robust stability, underscore its efficacy as a versatile tool for vanillin detection. Indeed, its successful deployment in monitoring food samples underscores its applicability across diverse culinary contexts, further cementing its status as a pivotal asset in safeguarding food quality and consumer well-being.

Scattering/Fluorescence Dual-Mode Imaging in MnO2-Coated Silicon Nanospheres for Cancer Cell Detection.

A tumor microenvironment (TME)-responsive nanoprobe composed of a fluorescent dye-decorated silicon (Si) nanosphere core and a thin MnO2 shell is proposed for simple and intelligent detection of cancer cells. The Si nanosphere core with diameters of 100-200 nm provides environment-independent Mie scattering imaging, while, simultaneously, the MnO2 shell provides the capability to switch the on/off state of the dye fluorescence reacted to the glutathione (GSH) and/or H2O2 levels in a cancer cell. Si-MnO2 core-shell nanosphere probes are fabricated in a solution-based process from crystalline Si nanosphere cores. The fluorescence switching under exposure to GSH is demonstrated, and the mechanism is discussed based on detailed optical characterizations including single-particle spectroscopy. Different types of human cells are incubated with the nanoprobes, and a proof of concept experiment is performed. From the combination of the robust scattering images and GSH- and H2O2-sensitive fluorescence images, the feasibility of cancer cell detection by the multimodal nanoprobes is demonstrated.

A Novel Electrochemical Sensor Based on Pd Confined Mesoporous Carbon Hollow Nanospheres for the Sensitive Detection of Ascorbic Acid, Dopamine, and Uric Acid.

In this study, we designed a novel electrochemical sensor by modifying a glass carbon electrode (GCE) with Pd confined mesoporous carbon hollow nanospheres (Pd/MCHS) for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The structure and morphological characteristics of the Pd/MCHS nanocomposite and the Pd/MCHS/GCE sensor are comprehensively examined using SEM, TEM, XRD and EDX. The electrochemical properties of the prepared sensor are investigated through CV and DPV, which reveal three resolved oxidation peaks for AA, DA, and UA, thereby verifying the simultaneous detection of the three analytes. Benefiting from its tailorable properties, the Pd/MCHS nanocomposite provides a large surface area, rapid electron transfer ability, good catalytic activity, and high conductivity with good electrochemical behavior for the determination of AA, DA, and UA. Under optimized conditions, the Pd/MCHS/GCE sensor exhibited a linear response in the concentration ranges of 300-9000, 2-50, and 20-500 µM for AA, DA, and UA, respectively. The corresponding limit of detection (LOD) values were determined to be 51.03, 0.14, and 4.96 µM, respectively. Moreover, the Pd/MCHS/GCE sensor demonstrated outstanding selectivity, reproducibility, and stability. The recovery percentages of AA, DA, and UA in real samples, including a vitamin C tablet, DA injection, and human urine, range from 99.8-110.9%, 99.04-100.45%, and 98.80-100.49%, respectively. Overall, the proposed sensor can serve as a useful reference for the construction of a high-performance electrochemical sensing platform.

Unlocking enhanced photocatalytic power: Donor-acceptor synergy in non-metallic g-C3N4 hollow nanospheres.

Selecting safe, non-toxic, and non-metallic semiconductor materials that facilitate the degradation of pollutants in water stands out as an optimal approach to combat environmental pollution. Herein, graphitic carbon nitride (g-C3N4)-based hollow nanospheres nonmetallic photocatalyst modified with covalent organic framework materials named TpMA, based on 1, 3, 5-trimethylchloroglucuronide (Tp) and melamine (MA), was successfully synthesized (abbreviated as CNTP). The ordered electron donor-acceptor structure inherent in TpMA contributed to enhancing the transport efficiency of photogenerated carriers in CNTP. The CNTP photocatalysts exhibited excellent performance in degrading rhodamine B and tetracycline in visible light, with optimal degradation rates reached more than 90% in 60 and 80 min, respectively, which were 5.3 and 3.0 times higher than those of pure CNNS. The increased photocatalytic efficiency observed in CNTP composites could be traced back to the covalently connection between the two molecules, forming a π-conjugated system that facilitated the separative efficiency of photogenerated electron-hole pairs and intensified the utilization of visible light. This study provided a new means to design and fabricate highly efficient and environmentally friendly non-metallic photocatalytic materials.

Fully upgrade bamboo biomass into three multifunctional products through biphasic γ-valerolactone and aqueous phosphoric acid pretreatment.

In this manuscript, three components of lignocellulosic biomass were obtained by deconstructing bamboo with γ-valerolactone-H2O biphasic system, and the delignification rate of 80.92 % was achieved at 120 °C for 90 min. Lignin nanospheres with diameters ranging from 75 nm to 2 um could be customized by varying the self-assembly rate. Furthermore, the lignin nanospheres-poly(vinyl alcohol) film was prepared by cross-linking lignin nanospheres and poly(vinyl alcohol), which can obtain 90 % ultraviolet absorption capacity, while the light transmittance in non-ultraviolet band was almost unchanged. At the same time, due to the strong hydrogen formation between lignin nanospheres and poly(vinyl alcohol) bond network, the tensile properties of the composite film were also improved by 30 %. Besides, the high specific surface area of biomass-derived porous biochar (2056 m2/g) can be obtained after carbonization of solid residues at 850 °C for 2 h, which was almost 8 times the specific surface area of the direct biomass carbonization due to the removal of lignin and hemicellulose. biomass-derived porous biochar can be used as an adsorbent, with a CO2 capture capacity of 4.5 mmol g-1 at normal temperature (25 °C, 1 bar). The filtrate after the reaction contained a large amount of hemicellulose oligomers, which can be reacted with dichloromethane at 170 °C for 1 h to obtain the furfural yield of 74 %. In summary, the proposed biorefinery scheme achieves a full-component upgrade of lignocellulose and can be further applied in various downstream fields.

A cavity induced mode hybridization plasmonic sensor for portable detection of exosomes.

Exosomes have been considered as promising biomarkers for cancer diagnosis due to their abundant information from originating cells. However, sensitive and reliable detection of exosomes is still facing technically challenges due to the lack of a sensing platform with high sensitivity and reproducibility. To address the challenges, here we propose a portable surface plasmon resonance (SPR) sensing of exosomes with a three-layer Au mirror/SiO2 spacer/Au nanohole sensor, fabricated by an economical polystyrene nanosphere self-assembly method. The SiO2 spacer can act as an optical cavity and induce mode hybridization, leading to excellent optimization of both sensitivity and full width at half maximum compared with normal single layer Au nanohole sensors. When modified with CD63 or EpCAM aptamers, a detection of limit (LOD) of as low as 600 particles/µL was achieved. The sensors showed good capability to distinguish between non-tumor derived L02 exosomes and tumor derived HepG2 exosomes. Additionally, high reproducibility was also achieved in detection of artificial serum samples with RSD as low as 2%, making it feasible for clinical applications. This mode hybridization plasmonic sensor provides an effective approach to optimize the detection sensitivity of exosomes, pushing SPR sensing one step further towards cancer diagnosis.

A Reactive Oxygen Species "Sweeper" Based on Hollow Mesopore Cerium Oxide Nanospheres for Targeted and Anti-Inflammatory Management of Osteoarthritis.

Osteoarthritis (OA) is a progressive joint disorder characterized by sustained oxidative stress, chronic inflammation, and the degradation of cartilage. Despite extensive research on nanocarrier treatment strategies, the therapeutic efficacy remains limited due to the lack of satisfactory vehicles that can simultaneously exhibit excellent ROS scavenging capabilities and high drug loading capacity for effective nonsurgical management of OA. In this work, we propose an innovative strategy utilizing hollow mesoporous cerium oxide nanospheres coated with membranes derived from apoptotic chondrocytes as a reactive oxygen species "sweeper" for targeted and anti-inflammatory therapy of OA. The developed DEX@HMCeNs@M demonstrates superior drug loading capacity, notable antioxidant properties, favorable biocompatibility, and controlled drug release. By leveraging the camouflage provided by apoptotic chondrocyte membranes, the engineered DEX@HMCeNs@M, which bear natural "eat me" signals, can effectively mimic chondrocyte apoptotic bodies within the joints, thereby enabling targeted delivery of the anti-inflammatory drug DEX and subsequent controlled release triggered by the acidic environment of OA. Both in vitro and in vivo experiments validate the enhanced therapeutic efficacy of our DEX@HMCeNs@M sweeper, which operates through a synergistic mechanism involving scavenging of ROS overproduction, inhibition of inflammation, restoration of mitochondrial damage, and reduction of chondrocyte apoptosis. These findings underscore the potential and efficiency of our developed DEX@HMCeNs@M strategy as an encouraging interventional approach for the progressive treatment of OA.

N-rich carbon nanosphere as fluorescent nanoprobe for intracellular iron.

Nitrogen rich carbon nanoparticles are known to provide higher fluorescence stokes shift, and thereby are potential candidates for fluorescent sensors. Herein, a facile one-step hydrothermal synthesis is reported for N-rich carbon nanospheres (G-CNS) from caffeine and o-phenylenediamine as precursors. The as-synthesized G-CNS showed high fluorescence with λem at 509 nm, with a highly selective fluorescence turn-off response towards Fe2+/Fe3+, rendering these carbon nanospheres as potential candidates to detect intracellular labile iron pool in live cells. The intracellular labile iron pool in iron-overloaded cells was sensed using the synthesized G-CNS. Mechanistically, the fluorescence quenching via dynamic pathway involves the formation of an excited state charge transfer process, which undergoes non-radiative decay.

Spatially confined CuFe2O4 nanosphere in N/O-codoped porous carbon mimetics for triple-mode sensing of antibiotics and visual detection of neurotransmitters in biofluids.

BACKGROUND: Carbon-based nanozymes have recently received enormous concern, however, there is still a huge challenge for inexpensive and large-scale synthesis of magnetic carbon-based "Two-in-One" mimics with both peroxidase (POD)-like and laccase-like activities, especially their potential applications in multi-mode sensing of antibiotics and neurotransmitters in biofluids. Although some progresses have been made in this field, the feasibility of biomass-derived carbon materials with both POD-like and laccase-like activities by polyatomic doping strategy is still unclear. In addition, multi-mode sensing platform can provide a more reliable result because of the self-validation, self-correction and mutual agreement. Nevertheless, the use of magnetic carbon-based nanozyme sensors for the multi-mode detection of antibiotics and neurotransmitters have not been investigated. RESULTS: We herein report a shrimp shell-derived N, O-codoped porous carbon confined magnetic CuFe2O4 nanosphere with outstanding laccase-like and POD-like activities for triple-mode sensing of antibiotic d-penicillamine (D-PA) and chloramphenicol (CPL), as well as colorimetric detection of neurotransmitters in biofluids. The magnetic CuFe2O4/N, O-codoped porous carbon (MCNPC) armored mimetics was successfully fabricated using a combined in-situ coordination and high-temperature crystallization method. The synthesized MCNPC composite with superior POD-like activity can be used for colorimetric/temperature/smartphone-based triple-mode detection of D-PA and CPL in goat serum. Importantly, the MCNPC nanozyme can also be used for colorimetric analysis of dopamine and epinephrine in human urine. SIGNIFICANCE: This work not only offered a novel strategy to large-scale, cheap synthesize magnetic carbon-based "Two-in-One" armored mimetics, but also established the highly sensitive and selective platforms for triple-mode monitoring D-PA and CPL, as well as colorimetric analysis of neurotransmitters in biofluids without any tanglesome sample pretreatment.