Dynamic Laser Light Scattering Research Articles

Preparation, in vitro and in vivo evaluation of a novel mitiglinide microemulsions

This study aimed to prepare an o/w mitiglinide microemulsion (MTGME) to improve the drug solubility and bioavailability. The formulation of o/w MTGME was optimized by the solubility study of drug, pseudo-ternary phase diagram and Box-Behnken design successively. MTGME was characterized by dynamic laser light scattering (DLS), zeta potential and transmission electron microscopy (TEM), moreover, the storage stability, pharmacodynamics and pharmacokinetics were investigated. The optimal prescription for MTGME consisted of Maisine 35–1 (oil), Cremophor EL (surfactant) and propylene glycol (PG, cosurfactant). MTGME with a spherical dimension of 58.1 ± 5.86 nm was stable when stored at 4 °C for 3 months. The blood glucose levers (BGL) of diabetic mice were uniformly and significantly decreased by intragastric (i.g.) administration of 1–4 mg/kg MTGME, in which BGL (i.g. 4 mg/kg MTGME) was reduced by 69% during 24 h. The pharmacokinetics study of MTGME (i.g., 20 mg/kg) in Wistar rats showed higher plasma drug concentration (Cmax, 2.9 folds), larger area under curve (AUC, 4.6 folds) and oral bioavailability than those of MTG suspensions. Generally, the MTGME (o/w) showed good effect on controlling hyperglycemia. Therefore, microemulsion can be used as an effective oral drug delivery system to improve the bioavailability of MTG.

Determination of the Microplastic Particle Release by Tea Bags During Brewing

The presence of microscopic particles of plastic (MP) in food is currently an urgent problem in the modern food industry and one of the main issues of food safety. However, there are no clear methods for the determination of such particles, nor methods for cleaning food products from them. In the present work, for the first time, the method of Dynamic Laser Light Scattering (DLS) was used to determine the plastic nanoparticles from tea bags when they were boiled in boiling water. It has been established that some of the studied samples of sachets release a huge amount of such nanoparticles into water. Moreover, hundreds of millions of nanoparticles are released per one microscopic particle. Pyramidal tea bags release a huge amount of nanoparticles with a diameter of 1 to 2 nm. The number of nanoparticles released during thermal action on pyramidal tea bags is at least 23 times greater than the number of the

Determination of the microplastic particle release by tea bags during brewing

The presence of microscopic particles of plastic (MP) in food is currently an urgent problem in the modern food industry and one of the main issues of food safety. However, there are no clear methods for the determination of such particles, nor methods for cleaning food products from them. In the present work, for the first time, the method of Dynamic Laser Light Scattering (DLS) was used to determine the plastic nanoparticles from tea bags when they were boiled in boiling water. It has been established that some of the studied samples of sachets release a huge amount of such nanoparticles into water. Moreover, hundreds of millions of nanoparticles are released per one microscopic particle.

Applying of Chitosan-TiO2 Nanocomposites for Photocatalytic Degradation of Anthracene and Pyrene

In this work, chitosan-TiO2 nanocomposites (NСs CS-TiO2) were developed for the photocatalytic degradation of some representatives of polycyclic aromatic hydrocarbons (PAHs). TiO2 nanoparticles (NPs) were synthesized by laser ablation method and their sizes were determined by dynamic laser light scattering (DLLS). Anthracene and pyrene in micellar solution were used as representatives of PAHs. The effect of TiO2 in the composition of prepared nanocomposites on the photodegradation of PAHs in model environments under UV irradiation was studied. The method of solid-phase luminescence (SPL) was used to estimate the decrease in PAHs concentrations. Based on the results of the studies carried out, pseudo-first order photodegradation kinetics were plotted. The efficiency of using the nanocomposites for the photocatalytic degradation of anthracene and pyrene was proved.

Construction of supramolecular hyperbranched polymers based on a tetrathiafulvalene derivative: Self-assembly and charge transfer interaction with TCNQ

In the present work, a four naphthyl-armed tetrathiafulvalene derivative (TTFB) was designed and synthesized through one-step reaction. Based on the host–guest interaction between naphthyl and cucurbit[8]uril (CB[8]), supramolecular hyperbranched polymers (SHPs) can be constructed in water, depending on hydrogen nuclear magnetic resonance (1H NMR) spectra, UV–vis absorption spectroscopy and diffusion-ordered NMR spectroscopy (DOSY). The self-assembly properties of the SHPs were further investigated by zeta potential analyzer, dynamic laser light scattering (DLS) and transmission electron microscopy (TEM) measurements, which exhibited positively charged spherical structures with the diameter at ~120 nm. More interestingly, the SHPs can interact with TCNQ (7,7,8,8-tetracyanoquinodimethane) to form charge transfer complexes through charge transfer interaction. Meanwhile, the self-assembly structures can be transformed from spherical structures to crosslinked nanoparticles in the charge transfer complexes state.

Determining the Aspect Ratio of Palygorskite by Dynamic Laser Light Scattering and X-Ray Diffraction Analysis Techniques

As a natural two-dimensional nanomaterial, palygorskite has been widely used in the fields of biology, chemical industry, medicine, and agriculture. Recently, more and more researchers point out that the aspect ratio of palygorskite directly affects the properties of its composite materials. Due to the large specific surface area and the tiny width of the palygorskite rod-like particles, it is difficult to obtain the aspect ratio information quickly and accurately by conventional means such as microphotography method and specific surface area method. In this paper, the length and width of the crystal is measured quickly and accurately by using dynamic laser light scattering technique and X-ray diffraction technique, so that the aspect ratio of the crystal can be calculated easily. It is recommended to analyze the crystallite size and microstrain of the diffraction pattern of palygorskite that using Pearson VII function, Caglioti equation, and average (LANGFORD) method, after comparing the three modes of W.-H. method. This feasible method has a good application prospect of the study of rod-like nanomaterials.

Genipin cross-linked blue Lys-FA nanoparticles for targeted visible glioma cell staining and drug delivery

Design and fabrication of multifunctional nano-carrier is a promising tool in the field of nanomedicine for glioma theranostics. In this study, blue color nanoparticles with targeted tumor cell staining and drug delivery capabilities were simply fabricated by crosslinking lysine (Lys) and lysine-folic acid (Lys-FA) mixture with genipin as the crosslinking agent through a reversed microemulsion method. Doxorubicin (DOX) as the model drug was loaded through electrostatic interaction. The nanoparticles before (Lys-FA NPs) and after (Lys-FA/DOX NPs) loading of DOX were characterized by ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic laser light scattering (DLS), transmission electron microscopy (TEM), and fluorescence spectroscopy. Ultimately, the glioma cell staining ability of Lys-FA NPs and cytotoxicity of Lys-FA/DOX NPs were tested in vitro. The results showed that the particle size of Lys-FA NPs can be tuned by adjusting the ratio of Lys to Lys-FA simply. The Lys-FA NPs exhibited dark blue and the blue color is stable under different pH values and temperatures. The feature makes the staining glioma cell pellets visible to naked-eyes. The model drug DOX was loaded on Lys-FA NPs indicated by the increase of size and zeta potential, and change of optical properties. The DOX loaded on the Lys-FA NPs can be sustainedly released, other than burst release. Encouragingly, the Lys-FA NPs can deliver DOX into cells and dramatically reduce cell viability, as proved by U87 cell cytotoxicity analysis and confocal fluorescence imaging. In addition, the Lys-FA NPs (≤2.5 mg mL−1) are nontoxic to CHO cells. In a short, the blue color Lys-FA NPs can visibly stain glioma cell pellets and deliver DOX into glioma cells, which can potentially be applied as a multifunctional nanocarrier for tumor imaging and drug delivery.

Lipid/Hyaluronic Acid-Coated Doxorubicin-Fe3O4 as a Dual-Targeting Nanoparticle for Enhanced Cancer Therapy.

Development of a delivery system to lower systemic toxicity and enhance doxorubicin (DOX) antitumor efficacy against multi-drug resistant (MDR) tumors is of great clinical significance. Here, lipid/hyaluronic acid (HA)-coated DOX-Fe3O4 was characterized to determine its optimal safety and efficacy on a tumor. DOX was first conjugated onto the Fe3O4 NPs surface, which was subsequently coated with phosphatidylcholine (PC) lipids, which consisted of a tumor cell-targeting HA ligand, to generate a dual-targeting nanoparticle (NP). DOX-Fe3O4 synthesis was validated by the Fourier-transform infrared (FT-IR) analysis results. Core-shell PC/HA@DOX-Fe3O4 formation, which had an average particle size of 48.2nm, was observed based on the transmission electron microscopy (TEM) and dynamic laser light scattering (DLS) results. The saturation magnetization value of PC/HA@DOX-Fe3O4 was discovered to be 28emu/g using vibrating-sample magnetometry. Furthermore, the designed PC/HA@DOX-Fe3O4 achieved greater MCF-7/ADR cellular uptake and cytotoxicity as compared with DOX. In addition, PC/HA@DOX-Fe3O4 exhibited significant DOX tumor-targeting capabilities and enhanced tumor growth inhibition activity in the xenograft MCF-7/ADR tumor-bearing nude mice following magnetic attraction and ligand-mediated targeting, with less cardiotoxicity. Therefore, PC/HA@DOX-Fe3O4 is a potential candidate for MDR tumor chemotherapy. Graphical abstract.

Rhodamine labeled cellulose nanocrystals as selective “naked-eye” colorimetric and fluorescence sensor for Hg2+ in aqueous solutions

Novel rhodamine-based fluorescence cellulose nanocrystals (RhB-CNCs) were synthesized and investigated as an effective naked-eye colorimetric and fluorescent sensor for detection of Hg2+ in aqueous solutions. RhB-CNCs were characterized by using FT-IR, XRD, XPS, TEM, AFM, ζ-potential measurements, dynamic laser light scattering (DLS), UV–vis absorption and fluorescence spectroscopy. The average dimension of RhB-CNCs was about 18–20 nm in width and 160–180 nm in length, which could be stably dispersed in aqueous solutions. RhB-CNCs were able to selectively recognize Hg2+ by “naked-eye” and spectroscopic method in aqueous solutions. The fluorescent and colorimetric detection limits were determined to be 232 nM and 746 nM, respectively. This sensor could function in the pH range of 3–12 and exhibited excellent interference immunity. By means of Benesi–Hildebrand plot, 1:1 binding stoichiometry was obtained, and the binding constant between RhB-CNCs and Hg2+ was found to be 4.15 × 105 M−1. The fluorescent-labeled CNCs can be readily used for selective and sensitive detection of Hg2+ in aqueous media and exhibit great potential applications for chemosening, bioimaging and sewage treatment. Novel rhodamine-based fluorescence cellulose nanocrystals were prepared and used as an effective naked-eye colorimetric and fluorescent sensor for detection of Hg2+ in aqueous solutions.

Обнаружение частиц микропластика в растительных маслах

Наличие микро и нано частиц пластика в пищевых продуктах в настоящее время является актуальнейшей проблемой пищевой промышленности и одним из главных вопросов пищевой безопасности. При этом не существует ни чётких методик по определению таких частиц, ни способов очистки от них пищевых продуктов. В связи с тем, что вопрос о переработке пластика до сих пор не решён, а разлагающиеся пластиковые объекты находятся повсюду вокруг, крайне актуальным является изучение вопроса о наличии микроскопических частиц пластмасс (микропластика) в пищевых продуктах, об их размерах и количестве. В представленной работе впервые методом Динамического Лазерного Светорассеивания с помощью анализатора наночастиц «Zetatrac» было определено присутствие в некоторых растительных маслах микро и нано объектов, по своим характеристикам похожих на пластик. Определено распределение этих частиц по фракциям, их удельная поверхность и дзета потенциал. Было подсчитано содержание микро и нано частиц, идентифицированных, как пластик, в растительном масле. Оно колеблется от 2,5 до 9 миллиардов на один литр пищевого продукта. Высказано предположение, что возможной причиной наличия таких частиц в этом виде пищевых продуктов является то, что может происходить их экстракция из медленно разрушающейся пластиковой тары.Величина дзета потенциала, подсчитанная прибором на основании данных о движении частиц, находится в области от 20 до 30 мВ. Это значит, что микрочастицы в суспензии устойчивы и не склонны к коагуляции. Таким образом, самоочищение от них невозможно.

Ectopic chondrogenesis of nude mouse induced by nano gene delivery enhanced tissue engineering technology.

Background: Many techniques and methods have been used clinically to relieve pain from cartilage repair, but the long-term effect is still unsatisfactory.Purpose: The objective of this study was to form an artificial chondroid tissue gene enhanced tissue engineering system to repair cartilage defects via nanosized liposomes.Methods: Cationic nanosized liposomes were prepared and characterized using transmission electron microscope (TEM) and dynamic laser light scattering (DLS). The rat mesenchymal stem cells (rMSCs) were isolated, cultivated, and induced by SRY (Sex-Determining Region Y)-Box 9 (Sox9) via cationic nanosized liposomes. The induced rMSCs were mixed with a thermo-sensitive chitosan hydrogel and subcutaneously injected into the nude mice. Finally, the newly-formed chondroid tissue obtained in the injection parts, and the transparent parts were detected by HE, collagen II, and safranin O.Results: It was found that the presently prepared cationic nanosized liposomes had the diameter of 85.76±3.48 nm and the zeta potential of 15.76±2.1 mV. The isolated rMSCs proliferation was fibroblast-like, with a cultivated confluence of 90% confluence in 5–8 days, and stained positive for CD29 and CD44 while negative for CD34 and CD45. After transfection with cationic nanosized liposomes, we observed changes of cellular morphology and a higher expression of SOX9 compared with control groups, which indicated that rMSCs could differentiate into chondrocyte in vitro. By mixing transfected rMSCs with the thermo-sensitive hydrogel of chitosan in nude mice, chondroid tissue was successfully obtained, demonstrating that rMSCs can differentiate into chondrogenic cells in vivo. Conclusion: This study explored new ways to improve the quality of tissue engineered cartilage, thus accelerating clinical transformation and reducing patient pain.

Определение содержания наночастиц пластика в питьевой воде и жидких пищевых продуктах

Присутствие микроскопических частиц пластика в пищевых продуктах является актуальнейшей проблемой современной пищевой промышленности и одним из главных вопросов пищевой безопасности. При этом не существует ни чётких методик по определению таких частиц, ни способов очистки от них пищевых продуктов.В представленной работе впервые методом Динамического Лазерного Светорассеивания (ДЛСР) было определено наличие наночастиц разного химического состава в питьевой воде и некоторых напитках. Измерен размер найденных микро и нано объектов, их распределение по фракциям. С этой целью использован Лазерный анализатор наночастиц «Zetatrac» (США). Определена также средняя молекулярная масса обнаруженных частиц, их средняя удельная площадь поверхности и дзета потенциал. В некоторых образцах питьевой воды обнаружены как наночастицы пластика, так и ржавчины.

Aggregation-Induced Emission (AIE)-Labeled Cellulose Nanocrystals for the Detection of Nitrophenolic Explosives in Aqueous Solutions.

Aggregation-induced emission (AIE) active cellulose nanocrystals (TPE-CNCs) were synthesized by attaching tetraphenylethylene (TPE) to cellulose nanocrystals (CNCs). The structure and morphology of TPE-CNCs were characterized by FT-IR, XRD, ζ-potential measurements, elemental analysis, TEM, atomic force microscopy (AFM), and dynamic laser light scattering (DLS). Fluorescent properties of TPE-CNCs were also further studied. Unlike aggregation-caused quenching (ACQ), TPE-CNCs emitted weak fluorescence in the dilute suspensions, while emitting efficiently in the aggregated states. The AIE mechanism of TPE-CNCs was attributed to the restriction of an intramolecular rotation (RIR) process in the aggregated states. TPE-CNCs displayed good dispersity in water and stable fluorescence, which was reported through the specific detection of nitrophenolic explosives in aqueous solutions by a fluorescence quenching assay. The fluorescence emissions of TPE-CNCs showed quantitative and sensitive responses to picric acid (PA), 2,4-dinitro-phenol (DNP), and 4-nitrophenol (NP), and the detection limits were 220, 250, and 520 nM, respectively. Fluorescence quenching occurred through a static mechanism via the formation of a nonfluorescent complex between TPE-CNCs and nitrophenolic analytes. A fluorescence lifetime measurement revealed that the quenching was a static process. The results demonstrated that TPE-CNCs were excellent sensors for the detection of nitrophenolic explosives in aqueous systems, which has great potential applications in chemosensing and bioimaging.

Self-Assembly Fluorescent Cationic Cellulose Nanocomplex via Electrostatic Interaction for the Detection of Fe3+ Ions.

In this work, an aggregation-induced emission (AIE) sensor for the detection of Fe3+ ions was fabricated through the electrostatic interaction between 1,1,2-triphenyl-2-[4-(3-sulfonatopropoxyl)-phenyl]-ethene sodium salt (SPOTPE) and quaternized cellulose (QC). The structure and properties of the SPOTPE/QC nanocomplex were studied by using 1H NMR, spectrofluorophotometer, transmission electron microscopy (TEM), and dynamic laser light scattering (DLS). An aqueous solution of SPOTPE and QC resulted in a remarkably enhanced cyan fluorescence in comparison to that of the SPOTPE solution. Strong through-space electrostatic interaction between SPOTPE and QC is the main cause for the fluorescence emerging. The fluorescence of the SPOTPE/QC solutions show good stability over a wide pH range of 5.0–10.0. When introducing Fe3+ ions into the SPOTPE/QC solution, the fluorescence quenched within 5 s. SPOTPE/QC solutions exhibited high selectivity and sensitivity for the detection of Fe3+ ions with ignored interferences from other ions, and the detection limit was determined to be 2.92 × 10−6 M. The quenching mechanism was confirmed to be the consequence of the binding interactions between Fe3+ ions and SPOTPE/QC complex.

Versatile Construction of Single-Tailed Giant Surfactants with Hydrophobic Poly(ε-caprolactone) Tail and Hydrophilic POSS Head.

Giant surfactants refer to a new kind of amphiphile by incorporating functional molecular nanoparticles with polymer tails. As a size-amplified counterpart of small-molecule surfactants, they serve to bridge the gap between small-molecule surfactants and amphiphilic block copolymers. This work reports the design and synthesis of single-tailed giant surfactants carrying a hydrophobic poly(ε-caprolactone) (PCL) as the tail and a hydrophilic cage-like polyhedral oligomeric silsesquioxane (POSS) nanoparticle as the head. The modular synthetic strategy features an efficient “growing-from” and “click-modification” approach. Starting from a monohydroxyl and heptavinyl substituted POSS (VPOSS-OH), a PCL chain with controlled molecular weight and narrow polydispersity was first grown by the ring-opening polymerization (ROP) of ε-CL under the catalysis of stannous octoate, leading to a PCL chain end-capped with heptavinyl substituted POSS (VPOSS-PCL). To endow the POSS head with adjustable polarity and functionality, three kinds of hydrophilic groups, including hydroxyl groups, carboxylic acids, and amine groups, were installed to the periphery of POSS molecule by a high-efficiency thiol-ene “click” reaction. The compounds were fully characterized by NMR, gel permeation chromatography (GPC), MALDI-TOF mass spectrometry, and TGA analysis. In addition, the preliminary self-assembly study of these giant surfactants was also investigated by TEM and dynamic laser light scattering (DLS), which indicated that they can form spherical nanoparticles with different diameters in aqueous solution. This work affords a straightforward and versatile way for synthesizing single-tailed giant surfactants with diverse head surface functionalities.

Developing a nontoxic and biocompatible polymeric self-assembly by using RAFT methodology for biomedical application

The amphiphilic block copolymer poly(N-vinylpyrrolidone)-b-poly(N-vinylcarbazole) (PVP-b-PVK) was synthesized by reversible-deactivation radical polymerization (RDRP)using reversible addition-fragmentation chain transfer (RAFT) methodology by new chain transfer agent (CTA) i.e. benzyl piperidine dithiocarbamate (BPDC). The pseudo-first-order kinetics and linear evolution of the molar mass with N-vinylpyrrolidone (NVP) conversion were obtained with the molar mass dispersity (Ð) 1.30–1.41 in toluene. 1H NMR spectrum indicates the presence of chain-end functional groups on homopolymer and block copolymer. The above block copolymer get self-assembled and form micelles in the aqueous medium, the size of micelles is characterized by 1H NMR, transmission electron micrographs (TEM) and dynamic laser light scattering (DLS) analyses, and critical micelles concentration (CMC) was determined by UV–vis spectroscopy. Trypan blue exclusion and MTT assay were done to ensure the cytotoxic effect of PVP-b-PVK on different types of normal cells (thymocytes, splenocytes and macrophage), and no cytotoxic effect was shown by block copolymer on cells, while observed biocompatibility with cells was 200 mg/mL. Further, the beads of block copolymer releases (65%) highly water-soluble levofloxacin drug up to 8 h in a controlled manner at pH 7.4 (37 ± 0.2 °C), while loading of levofloxacin drug was 62% (w/w).

The Role of Non-Ionic Surfactants in Solubilization and Delivery of Sparingly Soluble Drug Naproxen Sodium (NS): A Case Study

Abstract Nonsteroidal anti-inflammatory hydrophobic drugs (NSAIDs) are amongst the most commonly given categories of drugs worldwide in the treatment of pain, irritation and some of them even fever in many conditions. Critical micelle concentration of NSAIDs with Naproxen sodium (NS) and its mixture with non-ionic surfactants i.e. Tween 20, Tween 40 and Tween 60 was investigated at 293 K, 303 K, 313 K and 323 K at different concentrations using surface tension and dynamic laser light scattering (DLS) techniques. Due to amphiphilic behaviour in aqueous solution NS form aggregates at sufficiently high concentration. Thermodynamic/adsorption properties like free energy of micellization (ΔGmic), enthalpy of micellization (ΔHmic), entropy of micellization (ΔSmic), Γmic and area per molecule (A2) of NS in the presence of surfactants were also measured at different temperatures. The results showed that the presence of surfactants favoured the ΔGmic and become more enhanced with increase in temperature. Further the solubility of drug is more favourable with increase in polyethylene chain in basic surfactant molecules i.e. 20–60, which indicates that Tween-60 enhanced the solubility of NS more comparatively to Tween-40 and Tween-20 and may be applied as best additive for solubilisation of NS.

Curcumin loading potentiates the neuroprotective efficacy of Fe3O4 magnetic nanoparticles in cerebellum cells of schizophrenic rats.

The aim of this study was to investigate the neurotoxic effects of Fe3O4 magnetic- CurNPs on isolated schizophrenia mitochondria of rats as an in vivo model. We designed CMN loaded superparamagnetic iron oxide nanoparticles (SPIONs) (Fe3O4 magnetic- CurNPs) to achieve an enhanced therapeutic effect. The physicochemical properties of Fe3O4 magnetic- CurNPs were characterized using X-ray diffraction (XRD), and dynamic laser light scattering (DLS) and zeta potential. Further, to prove Fe3O4 magnetic- CurNPs results in superior therapeutic effects, and also, the mitochondrial membrane potential collapse, mitochondrial complex II activity, reactive oxygen species generation, ATP level, cytochrome c release and histopathology of cerebellums were determined in brains of schizophrenic rats. We showed that effective treatment with CMN reduced or prevented Fe3O4 magnetic-induced oxidative stress and mitochondrial dysfunction in the rat brain probably, as well as mitochondrial complex II activity, MMP, and ATP level were remarkably reduced in the cerebellum mitochondria of treated group toward control (p < 0.05). Therewith, ROS generation, and cytochrome c release were notably (p < 0.05) increased in the cerebellum mitochondria of treated group compared with control group. Taken together, Fe3O4 magnetic- CurNPs exhibits potent antineurotoxicity activity in cerebellums of schizophrenic rats. This approach can be extended to preclinical and clinical use and may have importance in schizophernia treatment in the future. To our knowledge this is the first report that provides the Fe3O4 magnetic- CurNPs could enhance the neuroprotective effects of CMN in the Schizophrenia.

Preparation of Durable Antibacterial Cellulose with AgCl Nanoparticles

In this study, a facile method was developed to coat AgCl nanoparticles (NPs) onto knitted cotton fabrics. The AgCl NPs were characterized by ultraviolet absorption spectrum, X-ray diffraction (XRD) and dynamic laser light scattering (DLS). The AgCl NPs were coated onto cotton fabrics through a pad-dry-cure process with the assistance of 1,2,3,4- butanetetracarboxylic acid (BTCA). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), ICP-OES analysis and energy-dispersive X-ray spectroscopy (EDX) confirmed that AgCl NPs were successfully coated onto cotton fabrics. The prepared cotton samples exhibited excellent antimicrobial activity against both Gram-positive S. aureus and Gram-negative K. pneumonia bacteria. Rat skin fibroblast cytotoxicity testing demonstrated the treated cotton fabrics to be non-toxic. The washing durability evaluation showed that the antimicrobial function of cotton fabrics was durable to washing. In addition, the wrinkle resistance of the coated cotton fabrics was improved and there was no obvious change in whiteness.

A Method To Determine Θ Condition of a Polymer Solution

The internal motions of narrowly distributed flexible polymer chains in extremely dilute solutions were studied by dynamic laser light scattering (LLS). We focused on the temperature-dependent relative intensity of the internal motions AI/(AI + AD), where AI and AD are the scattered light intensities, respectively, related to the internal motions and diffusive relaxation and obtainable from their related peak areas when ⟨Rg2⟩q2 > 1, where ⟨Rg2⟩ and q are the radius of gyration and the scattering vector, respectively. The results from four different polymer solutions reveal a maximum or turning point of AI/(AI + AD) near the theta temperature (Θ), confirming that the thermal energy can excite more internal motions when two-body and higher-order interactions diminish. Our study illustrates that dynamic LLS can be used to determine the Θ condition in a better way, in which only one dilute solution is needed in comparison with a set of polymer solutions previously required.