High Colloidal Stability Research Articles

Green Synthesis of Silver Nanoparticles using <i>Lantana camara</i> Leaves Extract and <i>In Vitro</i> Evaluation of Oral Anti-cancer Activity

At present, green synthesized based drug delivery systems play a major role in the bio medical field. Lantana camara, also known as Unni chedi in Tamil, is an evergreen shrub that is involved in a variety of cancer diseases due to its pharmacological activity. In addition, the leaf extract of Lantana camara was found to have excellent anti cancer activity. The green synthesized AgNPs of Lantana camara leaves extract were more efficient against oral cancer. In this report, green synthesized nano-formulations in presence of AgNPs were formulated. The as prepared formulation was confirmed by UV spectroscopy, particle size and zeta potential, Scanning Electron Microscopy (SEM). In UV Spectroscopy the absorbance of the peak appears between the range of 200 to 300 nm corresponding to the formulation of AgNPs. The Zeta potential shows high colloidal stability; the average potential value is -12.6mV. The particle size results shown that the average size of AgNPs is 268.1 nm. The morphology and particle size determined using SEM analysis indicate spherical shaped particles. Further, the oral anti-cancer activity was evaluated on Squamous Cell Cancer (SCC-25) cell line. The cell line result shown is that the IC 50 value for AgNPs was 39µg/ml and the plant extract shown 145µg/ml, this indicates that the silver nanoparticles have more potential when compared to the leaf extract.

Free-Standing Molecularly Thin Amorphous Silica Nanosheets.

Recent progress in 2D materials has initiated new fields of molecularly thin amorphous materials with mysterious properties and structures. However, designed synthesis of molecularly thin amorphous silica still remains a challenge; whether free-standing molecularly thin amorphous silica nanosheets can exist is unclear. Here, this issue is addressed by using a new chemical protocol; solid-state surfactant lamellae withordered alkyl-chain arrangements can serve as superior templates guiding free-standing amorphous silica nanosheets. Simple sonication of the lamellar hybrids allows exfoliation into monolayer amorphous silica nanosheets with 0.9nm thickness. In addition, the nanosheets show thedistinctive feature ofhigh colloidal stability that enables atomic layer engineering of silica nanocoatings and dielectric nanofilms. The approach may shed new light on the properties and applications of old silica.

Understanding the versatile roles of cellulose nanocrystals in α-amylase immobilization, starch hydrolysis, colloidal stability and printability towards advanced starch based bio-latex performance

Recently starch based bio-latexes are facing serious bottlenecks in their preparation and applications especially at the aspects of high concentration, high colloidal stability and high rheological performance. Starch paste for bio-latex production at high concentration would be prone to retrogradation and inevitably deteriorate its performance. The excessive and uncontrollable α-amylase hydrolysis behavior of starch granules at low concentration below 30 wt% could severely affect the strengthening or binding ability of bio-latex. Herein, this study proposes a practical and effective strategy by using cationic cellulose nanocrystals (CCNC) as versatile carriers of α-amylase for the preparation of starch based bio-latex (SBL) to improve starch hydrolysis efficiency even at 50 wt% concentration. CCNC immobilized α-amylase (CCNC/E) can effectively regulate starch hydrolysis behavior with controllable amylose/ amylopectin molecular weight/ distribution for enhanced colloidal stability and viscoelasticity. Furthermore, the multifunctional roles of CCNC as excellent dispersants, nano-fillers and enhancers within starch colloids could impart SBL excellent rheological property and printability in pigmented coating and printing performance, by improving the coating surface, higher printing density/ picking velocity, and lower dot gain phenomenon, compared with the control latex samples. This study proposes a promising and practical approach for efficient production of 50 wt% starch based bio-latex with advanced performance and further valorizes the cellulose nanocrystals in the starch based biomaterials applications.

Zn (II)‐Doped Cesium Copper Halide Nanocrystals with High Quantum Yield and Colloidal Stability for High‐Resolution X‑Ray Imaging

AbstractScintillators are essential for high‐energy radiation detection in a variety of potential applications. However, due to complex fabrication processes and nanocrystal homogeneity, conventional scintillators are challenging to meet the need for cost‐effective, environmentally friendly, and flexible X‐ray detection. Here, monodisperse nanocrystals (NCs) with small grain size and colloidal stability are obtained by adjusting the doping concentration of Zn2+ ions and controlling the morphology uniformity of Cs3Cu2I5 NCs. The photoluminescence quantum yield (PLQY) for the optimal doping concentration is as high as 92.8%, which is a 28.5% improvement compared to nondoped NCs. Density functional theory calculations reveal that the Zn2+ dopant inclines to occupy Cu sites and the I‐rich condition suppresses the formation of I vacancy, enriching the excited electron density at the band‐edge to enhance the self‐trapped exciton emission. Moreover, high luminescence performance and flexible X‐ray scintillator films are prepared using Zn2+‐doped Cs3Cu2I5 NCs, with a spatial resolution of up to 15.7 lp mm–1. This work provides an effective strategy for the development of environmentally friendly, low‐cost, and efficient blue‐emitting 0D all‐inorganic metal halides, as well as shows their great potential for high‐performance flexible lead‐free and low‐toxicity X‐ray detector applications.

Advances in the Chemical Stabilization of MXenes.

MXenes are 2D nanomaterials with a wide array of possible compositions; they feature a unique combination of properties such as high electrical conductivity, hydrophilicity, and colloidal stability which makes them attractive for a variety of applications. However, the shelf life and industrial utility of MXenes face challenges due to their tendency to oxidize and disintegrate, particularly in dispersions. Thus, it is crucial to find effective ways to ensure the degradation stability of MXenes. This feature article reviews the key factors affecting the degradation of MXenes such as pH, concentration of the dispersion, humidity, and storage temperature. In addition, we review our group's progress in mitigating the degradation of MXenes such as low-temperature storage, the use of antioxidants, and thermal annealing, particularly for Ti3C2Tz. These simple approaches may allow for applications of MXenes on a commercial scale.

Metal-coordination synthesis of a natural injectable photoactive hydrogel with antibacterial and blood-aggregating functions for cancer thermotherapy and mild-heating wound repair.

Photothermal therapy (PTT) is a promising approach for treating cancer. However, it suffers from the formation of local lesions and subsequent bacterial infection in the damaged area. To overcome these challenges, the strategy of mild PTT following the high-temperature ablation of tumors is studied to achieve combined tumor suppression, wound healing, and bacterial eradication using a hydrogel. Herein, Bi2S3 nanorods (NRs) are employed as a photothermal agent and coated with hyaluronic acid to obtain BiH NRs with high colloidal stability. These NRs and allantoin are loaded into an injectable Fe3+-coordinated hydrogel composed of sodium alginate (Alg) and Farsi gum (FG), which is extracted from Amygdalus scoparia Spach. The hydrogel can be used for localized cancer therapy by high-temperature PTT, followed by wound repair through the combination of mild hyperthermia and allantoin-mediated induction of cell proliferation. In addition, an outstanding blood clotting effect is observed due to the water-absorbing ability and negative charge of FG and Alg as well as the porous structure of hydrogels. The hydrogels also eradicate infection owing to the local heat generation and intrinsic antimicrobial activity of the NRs. Lastly, in vivo studies reveal an efficient photothermal-based tumor eradication and accelerated wound healing by the hydrogel.

Hierarchical superparamagnetic metal-organic framework nanovectors as anti-inflammatory nanomedicines.

Among a plethora of drug nanocarriers, biocompatible nanoscale metal-organic frameworks (nanoMOFs) with a large surface area and an amphiphilic internal microenvironment have emerged as promising drug delivery platforms, mainly for cancer therapy. However, their application in biomedicine still suffers from shortcomings such as a limited chemical and/or colloidal stability and/or toxicity. Here, we report the design of a hierarchically porous nano-object (denoted as USPIO@MIL) combining a benchmark nanoMOF (that is, MIL-100(Fe)) and ultra-small superparamagnetic iron oxide (USPIO) nanoparticles (that is, maghemite) that is synthesized through a one-pot, cost-effective and environmentally friendly protocol. The synergistic coupling of the physico-chemical and functional properties of both nanoparticles confers to these nano-objects valuable features such as high colloidal stability, high biodegradability, low toxicity, high drug loading capacity as well as stimuli-responsive drug release and superparamagnetic properties. This bimodal MIL-100(Fe)/maghemite nanocarrier once loaded with anti-tumoral and anti-inflammatory drugs (doxorubicin and methotrexate) shows high anti-inflammatory and anti-tumoral activities. In addition, the USPIO@MIL nano-object exhibits excellent relaxometric properties and its applicability as an efficient contrast agent for magnetic resonance imaging is herein demonstrated. This highlights the high potential of the maghemite@MOF composite integrating the functions of imaging and therapy as a theranostic anti-inflammatory formulation.

Perylene dye@SiO2 core–shell nanoparticles with intense fluorescence

PD/CC@SiO2 core–shell nanoparticles (PD: perylene dye, CC: cholecalciferol/vitamine D3) show high colloidal stability in water, intense emission from red to yellow with quantum yields near unity, and excellent photostability.

WSe2 nanowires-based nanofluids for concentrating solar power

Tungsten selenide belongs to the family of inorganic compounds denominated transition metal dichalcogenides (TMDCs). There is emerging interest in these compounds in the field of optoelectronics, catalysis, sensing or energy storage, among others. Most works focus on the use of these materials in their 2D form but there is scarce research on the study of TMDCs nanomaterials with one-dimensional morphology. In this work, we explore the thermophysical properties of nanofluids based on 1D-WSe2 nanostructures with the aim of studying the feasibility of these nanofluids as heat transfer fluids in concentrating solar power plants. In this respect, nanofluids with a high heat transfer rate could increase the thermal efficiency of solar power plants, which would reduce the energy dependence on fossil fuels. Nanofluids of 0.02 wt%, 0.05 wt% and 0.10 wt% WSe2 concentrations have been prepared by the two-step method considering a thermal fluid used in solar power plants as the base fluid. The results of extinction coefficient evolution, ζ potential and particle size in suspension show a high colloidal stability over time of the prepared nanofluids mainly because of the high aspect ratio of the 1D-WSe2 nanomaterial. Additionally, the one-dimensionality and length of the synthesized nanowires favors the transport of heat in controlled directions, obtaining increases in thermal conductivity with respect to the base fluid of up to 16.8% in the highest concentration nanofluid. Improvements in isobaric specific heat of up to 15.7% and heat transfer of up to 20.8% compared to the base fluid have also been found. The results of this paper provide evidence that the presence of WSe2 nanowires induces increases in the thermal properties of the fluid commonly used in concentrating solar power plants without inducing agglomeration or sedimentation problems. Therefore, the nanofluids based on 1D-WSe2 nanostructures prepared in this work have a high potential to be used as heat transfer fluids in concentrating solar power plants based on parabolic trough collectors.

Dual functionality of ferrocene-based metallopolymers as radical scavengers and nanoparticle stabilizing agents.

The beneficial redox properties of ferrocene-based polymers have been utilized during in situ preparation of metallic nanoparticles, while such redox features also indicate a great promise in applications as free radical scavengers. Here, colloidal dispersions of an antioxidant nanozyme composed of amidine-functionalized polystyrene latex (AL) nanoparticles, negatively charged poly(ferrocenylsilane) (PFS(-)) organometallic polyions, and ascorbic acid (AA) were formulated. The AL was first functionalized with PFS(-). Increasing the polymer dose resulted in charge neutralization and subsequent charge reversal of the particles. The strength of repulsive interparticle forces of electrostatic nature was significant at low and high doses leading to stable colloids, while attractive forces dominated near the charge neutralization point giving rise to unstable dispersions. The saturated PFS(-) layer adsorbed on the surface of the AL (p-AL nanozyme) enhanced the colloidal stability against salt-induced aggregation without affecting the pH-dependent charge and size of the particles. The joint effect of PFS(-) and the AA in radical decomposition was observed indicating the antioxidant potential of the system. The immobilization of PFS(-) deteriorated its scavenging activity, yet the combination with AA improved this feature. The results indicate that p-AL-AA is a promising radical scavenger since the high colloidal stability of the particles allows application in heterogeneous systems, such as in industrial manufacturing processes, where antioxidants are required to maintain acceptable product quality.

Amplified Fenton-Based Oxidative Stress Utilizing Ultraviolet Upconversion Luminescence-Fueled Nanoreactors for Apoptosis-Strengthened Ferroptosis Anticancer Therapy

As an emerging anticancer strategy, ferroptosis has recently been developed in combination with current therapeutic modalities to overcome the existing limitations of conventional therapies. Herein, an ultraviolet (UV) upconversion luminescence-fueled nanoreactor is explored to combine ferroptosis and apoptosis through the UV-catalyzed Fenton reaction of an iron supplement (ferric ammonium citrate) loaded in a mesoporous silica layer in addition to the support of a chemotherapeutic agent (cisplatin) attached on the functionalized silica surface for the treatment of triple negative breast cancer (TNBC). The nanoplatform can circumvent the low penetration depth typical of UV light by upconverting near-infrared irradiation and emitting UV photons that convert Fe3+ to Fe2+ to boost the generation of hydroxyl radicals (·OH), causing devastating lipid peroxidation. Apart from DNA damage-induced apoptosis, cisplatin can also catalyze Fenton-based therapy by its abundant production of hydrogen peroxide (H2O2). As a bioinspired lipid membrane, the folate receptor-targeted liposome as the coating layer offers high biocompatibility and colloidal stability for the upconversion nanoparticles, in addition to prevention of the premature release of encapsulated hydrophilic compounds, before driving the nanoformulation to the target tumor site. As a result, superior antitumor efficacy has been observed in a 4T1 tumor-bearing mouse model with negligible side effects, suggesting that such a nanoformulation could play a pivotal role in effective apoptosis-strengthened ferroptosis TNBC therapy.

DNA-Directed Protein Anchoring on Oligo/Alkanethiol-Coated Gold Nanoparticles: A Versatile Platform for Biosensing Applications

Herein, we report on a smart biosensing platform that exploits gold nanoparticles (AuNPs) functionalized through ssDNA self-assembled monolayers (SAM) and the DNA-directed immobilization (DDI) of DNA-protein conjugates; a novel, high-sensitivity optical characterization technique based on a miniaturized gel electrophoresis chip integrated with online thermal lens spectrometry (MGEC-TLS), for the high-sensitivity detection of antigen binding events. Specifically, we characterized the physicochemical properties of 20 nm AuNPs covered with mixed SAMs of thiolated single-stranded DNA and bio-repellent molecules, referred to as top-terminated oligo-ethylene glycol (TOEG6), demonstrating high colloidal stability, optimal binder surface density, and proper hybridization capacity. Further, to explore the design in the frame of cancer-associated antigen detection, complementary ssDNA fragments conjugated with a nanobody, called C8, were loaded on the particles and employed to detect the presence of the HER2-ECD antigen in liquid. At variance with conventional surface plasmon resonance detection, MGEC-TLS characterization confirmed the capability of the assay to titrate the HER2-ECD antigen down to concentrations of 440 ng/mL. The high versatility of the directed protein-DNA conjugates immobilization through DNA hybridization on plasmonic scaffolds and coupled with the high sensitivity of the MGEC-TLS detection qualifies the proposed assay as a potential, easily operated biosensing strategy for the fast and label-free detection of disease-relevant antigens.

Differences in Human Plasma Protein Interactions between Various Polymersomes and Stealth Liposomes as Observed by Fluorescence Correlation Spectroscopy.

A significant factor hindering the clinical translation of polymersomes as vesicular nanocarriers is the limited availability of comparative studies detailing their interaction with blood plasma proteins compared to liposomes. Here, polymersomes are self-assembled via film rehydration, solvent exchange, and polymerization-induced self-assembly using five different block copolymers. The hydrophilic blocks are composed of anti-fouling polymers, poly(ethylene glycol) (PEG) or poly(2-methyl-2-oxazoline) (PMOXA), and all the data is benchmarked to PEGylated "stealth" liposomes. High colloidal stability in human plasma (HP) is confirmed for all but two tested nanovesicles. In situ fluorescence correlation spectroscopy measurements are then performed after incubating unlabeled nanovesicles with fluorescently labeled HP or the specific labeled plasma proteins, human serum albumin, and clusterin (apolipoprotein J). The binding of HP to PMOXA-polymersomes could explain their relatively short circulation times found previously. In contrast, PEGylated liposomes also interact with HP but accumulate high levels of clusterin, providing them with their known prolonged circulation time. The absence of significant protein binding for most PEG-polymersomes indicates mechanistic differences in protein interactions and associated downstream effects, such as cell uptake and circulation time, compared to PEGylated liposomes. These are key observations for bringing polymersomes closer to clinical translation and highlighting the importance of such comparative studies.

Synthesis of Magneto-Controllable Polymer Nanocarrier Based on Poly(N-isopropylacrylamide-co-acrylic Acid) for Doxorubicin Immobilization.

In this work, the preparation procedure and properties of anionic magnetic microgels loaded with antitumor drug doxorubicin are described. The functional microgels were produced via the in situ formation of iron nanoparticles in an aqueous dispersion of polymer microgels based on poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-PAA). The composition and morphology of the resulting composite microgels were studied by means of X-ray diffraction, Mössbauer spectroscopy, IR spectroscopy, scanning electron microscopy, atomic-force microscopy, laser microelectrophoresis, and static and dynamic light scattering. The forming nanoparticles were found to be β-FeO(OH). In physiological pH and ionic strength, the obtained composite microgels were shown to possess high colloid stability. The average size of the composites was 200 nm, while the zeta-potential was -27.5 mV. An optical tweezers study has demonstrated the possibility of manipulation with microgel using external magnetic fields. Loading of the composite microgel with doxorubicin did not lead to any change in particle size and colloidal stability. Magnetic-driven interaction of the drug-loaded microgel with model cell membranes was demonstrated by fluorescence microscopy. The described magnetic microgels demonstrate the potential for the controlled delivery of biologically active substances.

Efficient Tumor Eradication at Ultralow Drug Concentration via Externally Controlled and Boosted Metallic Iron Magnetoplasmonic Nanocapsules.

With the aim to locally enhance the efficacy of cancer nanotherapies, here we present metal iron based magnetoplasmonic drug-loaded nanocapsules (MAPSULES), merging powerful external magnetic concentration in the tumor and efficient photothermal actuation to locally boost the drug therapeutic action at ultralow drug concentrations. The MAPSULES are composed of paclitaxel-loaded polylactic-co-glycolic acid (PLGA) nanoparticles partially coated by a nanodome shape iron/silica semishell. The iron semishell has been designed to present a ferromagnetic vortex for incorporating a large quantity of ferromagnetic material while maintaining high colloidal stability. The large iron semishell provides very strong magnetic manipulation via magnetophoretic forces, enabling over 10-fold higher trapping efficiency in microfluidic channels than typical superparamagnetic iron oxide nanoparticles. Moreover, the iron semishell exhibits highly damped plasmonic behavior, yielding intense broadband absorbance in the near-infrared biological windows and photothermal efficiency similar to the best plasmonic nanoheaters. The in vivo therapeutic assays in a mouse xenograft tumor model show a high amplification of the therapeutic effects by combining magnetic concentration and photothermal actuation in the tumor, leading to a complete eradication of the tumors at ultralow nanoparticle and drug concentration (equivalent to only 1 mg/kg PLGA nanoparticles containing 8 μg/kg of paclitaxel, i.e., 100-500-fold lower than the therapeutic window of the free and PLGA encapsulated drug and 13-3000-fold lower than current nanotherapies combining paclitaxel and light actuation). These results highlight the strength of this externally controlled and amplified therapeutic approach, which could be applied to locally boost a wide variety of drugs for different diseases.

Fabrication, Characterization and In Planta Uptake of Engineered Surfactant Nanovesicles for the Delivery of the Biostimulant Sodium Copper Chlorophyllin.

Effective delivery of agrochemicals requires control over bioactive release kinetics coupled with effective penetration of the bioactive into plants. Herein, we demonstrate the fabrication of hybrid nanovesicles based on sodium dodecylbenzenesulfonate (SDBS) and cetyltrimethylammonium bromide (CTAB) for enabling effective delivery of the biostimulant sodium copper chlorophyllin (Cu-chl) into plants. SDBS-CTAB nanovesicles exhibited a particle size of 107 nm with a well-defined spherical morphology, while modified formulations that included small fractions of the unsaturated dopant Span 80 yielded larger nanovesicles that were softer and more irregular in shape. All nanovesicles maintained high colloidal stability over >4 weeks and enabled sustained Cu-chl release, with the incorporation of Span 80 into the membranes enabling controllable acceleration of the release rate. Nanovesicle encapsulation improved the photostability of Cu-chl bioactive 3-4 × relative to that of free Cu-chl and enabled significant penetration of Cu-chl into the plant root without inducing any significant phytotoxicity.

Sustainable curdlan biosynthesis by Rahnella variigena ICRI91 via alkaline hydrolysis of Musa sapientum peels and its edible, active and modified hydrogel for Quercetin controlled release

Despite the high demand for curdlan (Curd), its industrial implementation has not reached a mature stage due to the high cost of simple sugar feed stocks. Herein, Musa sapientum peels hydrolysate (MPH) was proposed for the first time as a sustainable medium for Curd generation and as an ameliorated functional biomaterial for quercetin (Quer) sustained release. In this study, banana peels have been hydrolysed by 3 % NaOH catalyst/ 60 °C, yielding high concentration of glucose 20.5 ± 0.04 and 24.3 ± 0.11 g/L and reducing sugar amount, respectively. Meanwhile, a novel local Rahnella variigena ICRI91 strain was isolated from soil, that was useful for Curd production and identified by 16S rRNA analysis. Furthermore, three-batch fermentation models were carried out using MPH for obtaining a sufficient yield of Curd. R. variigena ICRI91 accumulated a satisfactory Curd concentration; 10.3 ± 0.25 g/L; using 60 g/L MPH. On the other hand, the strain produced an impressive Curd yield; 21.5 ± 0.13 g/L with an attained productivity of 0.179 ± 0.01 g/L/h and a sugar consumption of 68 ± 0.25 % as the MPH content increased to 100 g/L. For the first time, Curd hydrogel was modified by different amount of Xylitol (Xyl), reaching good mechanical performance; 3.1 MPa and 75 % for tensile strength (TS) and elongation at break (EB), respectively. Curd/Xyl (3/5) hydrogel was then integrated with nanometer-sized quercetin nanocrystals (Quer NCs, 83 ± 0.12 nm) with high colloidal stability of −23 ± 0.05 mV. The interconnected H- bonding between Xyl and Curd was confirmed by FTIR and SEM. The generated biomaterial was tailored to exhibit a sustained Quer release over 72 h. It also has improved antibacterial efficacy against four bacterial pathogens compared to that of a free drug. In recognition of these merits, an edible polymeric nanomaterial has been proposed for the functional food and biomedicine sectors.

Color-selective labyrinth-like quantum dot nanobeads enable point-of-care dual assay of Mycotoxins

Complex nanoparticles with hybrid forms of quantum dots and nano-scale templates are highly interesting due to various functionalities and broad applications in point-of-care testing (POCT). High sensitivity and throughput are significant for POCT in clinical applications and food safety, especially for determining multiple targets in complex matrices. Here, we developed the labyrinth-like quantum dot nanobeads (LQDBs) with controlled size, enhanced loading capacity and an intelligent mobile detection format. We reported a smartphone readout using color-selective LQDBs as fluorescent labels for POCT of dual targets in paper-test format. The labyrinth-like nanobeads assembled with QDs provided high colloidal stability, facile functionalization, and a rough surface for more binding sites to monoclonal antibodies enabled by a thin silica layer coating. Using LQDB, the POCT of dual targets was developed assisted with an in-house application on a smartphone. This assay detected aflatoxin B1 (AFB1) and zearalenone (ZEN) within 10 min using a competitive immunoassay. The LODs for urine and agricultural products were recorded as 0.002 and 0.02 ng/mL for AFB1 and ZEN, respectively. Reasonable specificity, repeatability, reproducibility, and validation results were recorded in real samples. This biosensing platform can be widely suitable in clinical healthcare and food safety applications.

Lignin emulsifying rosin for improved sizing performance and mechanical properties of liquid packaging board

Global liquid packaging industry has been greatly spurred by the rapidly growing food & beverage industry all over the world. Liquid packaging board (LPB), as the main composition (75–80 %) of laminated liquid packaging cartons, must possess high-quality of hydrophobicity and physical properties for excellent leak-proof and protecting the packaged commodity. Herein, in this study, lignin is selected to prepare lignin cationic surfactant (LCS) by quaternary ammonium modification. Then cationic lignin modified rosin size ( L -CDRS) with uniform microsphere structure and high colloidal stability is successfully synthesized via a phase inversion process to improve the sizing performance and mechanical properties of LPB. The cation modified LCS presents improved amphipathicity of rich cationic charges and hydrophobic benzene ring skeleton, thus enhancing the electrostatic interactions between LCS and pulp fibers and improving the sizing performance of L -CDRS. The sizing performance of LPB is evaluated by varying the LCS dosages within L -CDRS and concluded that the edge penetration value and Cobb value of LPB handsheets exhibit an improved size performance with 2 % LCS within L -CDRS, implying the formation of homogeneous hydrophobic surface layer induced by the well-distribution of L -CDRS. In addition, the tensile index of LPB increased from 19.74 N·m/g to 25.96 N·m/g assisted by 2 % LCS emulsified L -CDRS, indicating an improved mechanical property. This study puts forward a practical and facile strategy to improve the sizing performance and mechanical properties facilitated by lignin enhanced rosin size and will further broaden the application range of traditional rosin size and lignin in LPB products. • Lignin was modified into quaternary ammonium etherified cationic surfactant with improved emulsifying ability. • Cationic lignin can emulsify rosin to prepare L -CDRS with uniform microsphere structure and high colloidal stability. • L -CDRS exhibited a significantly improved sizing performance of LPB compared with the control rosin size. • The addition of L -CDRS contributed greatly to the enhanced mechanical properties of LPB. • The mechanism of improved sizing performance and mechanical properties of LPB induced by L -CDRS size agent was proposed.

A Simple Colorimetric Assay of Bleomycin-Mediated DNA Cleavage Utilizing Double-Stranded DNA-Modified Gold Nanoparticles.

A colorimetric assay of DNA cleavage by bleomycin (BLM) derivatives was developed utilizing high colloidal stability on double-stranded (ds) DNA-modified gold nanoparticles (dsDNA-AuNPs) possessing a cleavage site. The assay was performed using dsDNA-AuNPs treated with inactive BLM or activated BLM (Fe(II)⋅BLM). A 10-min exposure in dsDNA-AuNPs with inactive BLM treatment resulted in a rapid color change from red to purple because of salt-induced non-crosslinking aggregation of dsDNA-AuNPs. In contrast, the addition of active Fe(II)⋅BLM retained the red color, probably because of the formation of protruding structures at the outermost phase of dsDNA-AuNPs caused by BLM-mediated DNA cleavage. Furthermore, the results of our model experiments indicate that oxidative base release and DNA-cleavage pathways could be visually distinguished with color change. The present methodology was also applicable to model screening assays using several drugs with different mechanisms related to antitumor activity. These results strongly suggest that this assay with a rapid color change could lead to simple and efficient screening of potent antitumor agents.