High Adsorption of Sulfamethoxazole by an Amine-Modified Polystyrene-Divinylbenzene Resin and Its Mechanistic Insight.

Sulfamethoxazole (SMZ) adsorption by a series of amine-modified polystyrene-divinylbenzene resins (PSA/B/C/D) was investigated. All resins showed a similar pH dependent adsorption of SMZ but their capacities were linearly related with the contents of primary amines (-NH2) rather than secondary amines (-NH-). Mechanisms of SMZ adsorption by PSA (highest -NH2 content) were discussed as an example. Due to comparable pKa, H-bonding interactions of -NH2(0) with SMZ(0) (regular H-bond) and SMZ(-) (negative charge-assisted H-bond, (-)CAHB) successively contributed most adsorption (pH 4-9). At weakly acidic pH, -NH2(0) was partially protonated and electrostatic attraction between -NH3(+) and SMZ(-) occurred concurrently, but could be hindered by increased loading of SMZ(0). Hydrophobic/ π-π interactions were not major mechanisms as phenanthrene and nitrobenzenes had little effect on SMZ adsorption. At alkaline pH, where SMZ(-) and -NH2(0) prevailed, adsorption was accompanied by the stoichiometric (∼1.0) proton exchange with water, leading to OH(-) release and the formation of (-)CAHB [SO2N(-)···H···NH2]. The interaction and SMZ spatial distribution in the resin-phase were further confirmed by FTIR and Raman spectra. SMZ was uniformly adsorbed on external and interior surfaces. SMZ adsorption by PSA had low-interference from other coexistent matter, but high stability after multiple regenerations. The findings will guide new adsorbent designs for selectively removing target organics.

Doxorubicin-Loaded Carborane-Conjugated Polymeric Nanoparticles as Delivery System for Combination Cancer Therapy.

Carborane-conjugated amphiphilic copolymer nanoparticles were designed to deliver anticancer drugs for the combination of chemotherapy and boron neutron capture therapy (BNCT). Poly(ethylene glycol)-b-poly(L-lactide-co-2-methyl-2(2-dicarba-closo-dodecarborane)propyloxycarbonyl-propyne carbonate) (PLMB) was synthesized via the versatile reaction between decaborane and side alkynyl groups, and self-assembled with doxorubicin (DOX) to form drug-loaded nanoparticles. These DOX@PLMB nanoparticles could not only suppress the leakage of the boron compounds into the bloodstream due to the covalent bonds between carborane and polymer main chains, but also protect DOX from initial burst release at physiological conditions because of the dihydrogen bonds between DOX and carborane. It was demonstrated that DOX@PLMB nanoparticles could selectively deliver boron atoms and DOX to the tumor site simultaneously in vivo. Under the combination of chemotherapy and BNCT, the highest tumor suppression efficiency without reduction of body weight was achieved. This polymeric nanoparticles delivery system could be very useful in future chemoradiotherapy to obtain improved therapeutic effect with reduced systemic toxicity.

Analysis of silver nanoparticles in antimicrobial products using surface-enhanced Raman spectroscopy (SERS).

Silver nanoparticles (AgNPs) are the most commonly used nanoparticles in consumer products. Concerns over human exposure to and risk from these particles have resulted in increased interest in novel strategies to detect AgNPs. This study investigated the feasibility of surface-enhanced Raman spectroscopy (SERS) as a method for the detection and quantification of AgNPs in antimicrobial products. By using ferbam (ferric dimethyl-dithiocarbamate) as an indicator molecule that binds strongly onto the nanoparticles, AgNPs detection and discrimination were achieved based on the signature SERS response of AgNPs-ferbam complexes. SERS response with ferbam was distinct for silver ions, silver chloride, silver bulk particles, and AgNPs. Two types of AgNPs with different coatings, citrate and polyvinylpirrolidone (PVP), both showed strong interactions with ferbam and induced strong SERS signals. SERS was effectively applicable for detecting Ag particles ranging from 20 to 200 nm, with the highest signal intensity in the 60-100 nm range. A linear relationship (R(2) = 0.9804) between Raman intensity and citrate-AgNPs concentrations (60 nm; 0-20 mg/L) indicates the potential for particle quantification. We also evaluated SERS detection of AgNPs in four commercially available antimicrobial products. Combined with ICP-MS and TEM data, the results indicated that the SERS response is primarily dependent on size, but also affected by AgNPs concentration. The findings demonstrate that SERS is a promising analytical platform for studying environmentally relevant levels of AgNPs in consumer products and related matrices.

Use of asymmetric multilayer polylactide nanofiber mats in controlled release of drugs and prevention of liver cancer recurrence after surgery in mice.

Local tumor recurrence remains a major clinical problem following surgical treatment for most cancers such as hepatocellular carcinoma (HCC). An implantable local drug delivery system may be suitable for addressing this unmet clinical need. In this study, asymmetric multilayer polylactide nanofiber (AMPN) mats were prepared and a one-sided and prolonged release profile of hydrophilic dye or oxaliplatin was observed after they were sandwiched between two liver lobes in mice. Covering the surgery site by drug-loaded AMPN mat after tumor resection, in both subcutaneous and orthotopic HCC model in mice, the recurrence of HCC was significantly retarded and the survival time of mice was markedly prolonged. In conclusion, post-surgical therapy at tumor resection margins by drug-loaded AMPN mats may represent a suitable application of nanofiber-based local chemotherapy. FROM THE CLINICAL EDITOR: After cancer surgery, local recurrence remains a significant problem. In this study, the authors designed asymmetric multilayer PLA nanofiber (AMPN) mats and loaded them with anti-tumor drugs. Both in-vitro and in-vivo experiments showed good efficacy in preventing tumor recurrence. This novel product may point a way to the future and improve survival of cancer patients.

Green and chemical-free pretreatment of corn straw using cold isostatic pressure for methane production.

In this study, the effect of cold isostatic pressure (CIP) pretreatment on the physicochemical properties and subsequent anaerobic digestion (AD) performance of corn straw (CS) was explored. The CS was subjected to CIP pretreatment by pressures of 200, 400 and 600 MPa, respectively, while AD was carried out at medium temperature (35 ± 2 °C). The results showed that CIP pretreatment disrupted the dense structure of the CS and altered the crystallinity index and surface hydrophobicity of the CS, thereby affecting the AD process. The presence of CIP pretreatment increased the initial reducing sugar concentration by 0.11-0.27 g/L and increased the maximum volatile fatty acids content by 112.82-436.64 mg/L, which facilitated the process of acidification and hydrolysis of the AD. It was also observed that the CIP pretreatment maintained the pH in the range of 6.37-7.30, maintaining the stability of the overall system. Moreover, the cumulative methane production in the CIP pretreatment group increased by 27.17 %-64.90 % compared to the control group. Analysis of the microbial results showed that CIP pretreatment increased the abundance of cellulose degrading bacteria Ruminofilibacter from 21.50 % to 27.53 % and acetoclastic methanogen Methanosaeta from 45.48 % to 56.92 %, thus facilitating the hydrolysis and methanogenic stages. The energy conversion analysis showed that CIP is a green and non-polluting pretreatment strategy for the efficient AD of CS to methane.

An In Vitro Comparison of the Digestibility and Gastrointestinal Fate of Scallops and Plant-Based Scallop Analogs.

Concerns exist regarding the negative environmental impact and health risks associated with ocean fishing and aquaculture, such as stock depletion, pollution, biodiversity loss, and toxin presence. To address these concerns, plant-based seafood analogs are being developed. Our previous study successfully created plant-based scallop analogs using pea proteins and citrus pectin, resembling real scallops in appearance and texture. This study focuses on comparing the digestive fate of these analogs to real scallops, as it can impact their nutritional properties. Using an in vitro digestion model (INFOGEST), we simulated oral, gastric, and small intestinal conditions. The analysis revealed differences in the microstructure, physicochemical properties, and protein digestibility between the plant-based scallops and real scallops. The particle size and charge followed the following similar trends for both types of scallops: the particle size decreased from the mouth to the stomach to the small intestine; the particles were negative in the mouth, positive in the stomach, and negative in the small intestine. The protein digestibility of the plant-based scallops was considerably lower than that of real scallops. For instance, around 18.8% and 61.4% of protein was digested in the stomach and small intestine phases for the real scallop (80.2% total digestion), whereas around 8.7% and 47.7% of the protein was digested for the plant-based scallop (56.4% total digestion). The lower digestibility of the plant-based scallops may have been due to differences in the protein structure, the presence of dietary fibers (pectin), or antinutritional factors in the plant proteins. These findings are crucial for developing more sustainable next-generation plant-based seafood analogs.

A Second Near-Infrared Ru(II) Polypyridyl Complex for Synergistic Chemo-Photothermal Therapy.

The clinical success of cisplatin ushered in a new era of the application of metallodrugs. When it comes to practice, however, drug resistance, tumor recurrence, and drug systemic toxicity make it implausible to completely heal the patients. Herein, we successfully transform an electron acceptor [1, 2, 5]thiadiazolo[3,4-g]quinoxaline into a novel second near-infrared (NIR-II) fluorophore H7. After PEGylation and chelation, HL-PEG2k exhibits a wavelength bathochromic shift, enhanced photothermal conversion efficiency (41.77%), and an antineoplastic effect against glioma. Its potential for in vivo tumor tracking and image-guided chemo-photothermal therapy is explored. High levels of uptake and high-resolution NIR-II imaging results are thereafter obtained. The hyperthermia effect could disrupt the lysosomal membranes, which in turn aggravate the mitochondria dysfunction, arrest the cell cycle in the G2 phase, and finally lead to cancer cell apoptosis. HL-PEG2k displays a superior biocompatibility and thus can be a potential theranostic platform to combat the growth and recurrence of tumors.

Photocatalyzed surface modification of poly(dimethylsiloxane) with polysaccharides and assay of their protein adsorption and cytocompatibility.

An improved approach for the surface modification of poly(dimethylsiloxane) (PDMS) using carboxymethyl cellulose (CMC), carboxymethyl beta-1,3-dextran (CMD), and alginic acid (AA) was investigated. The PDMS substrates were first oxidized in a H(2)SO(4)/H(2)O(2) solution to transform the Si-CH(3) groups on their surfaces into Si-OH groups. Then methacrylate groups were grafted onto the substrates through a silanization reaction using 3-(trimethoxysilyl)propyl methacrylate. Sequentially, cysteamine was conjugated onto the silanized surfaces by the reaction between the thiol and methacrylate groups under 254 nm UV exposure. Afterward, the amino-terminated PDMS substrates were sequentially reacted with CMC, CMD, and AA in the presence of N-hydroxysuccinimide and 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide, resulting in the grafting of polysaccharides onto PDMS surfaces. The composition and chemical state of the modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS). In addition, the stability and dynamic characteristics of the polysaccharide-grafted PDMS substrates were investigated by XPS and temporal contact angle experiments. A protein adsorption assay using bovine serum albumin (BSA), chicken egg albumin, lysozyme, and RNase-A showed that the introduction of CMD and AA can reduce the adsorption of negatively charged BSA and chicken egg albumin, but increase the adsorption of the positively charged lysozyme and RNase-A. However, CMC-modified PDMS surfaces showed protein-repelling properties, regardless of whether the protein was positively or negatively charged. A cell culture and migration study of glioma C6, MKN-45, MCF-7, and HepG-2 cells revealed that the polysaccharide-modified PDMS greatly improved the cytocompatibility of native PDMS.

Factors impacting lipid digestion and nutraceutical bioaccessibility assessed by standardized gastrointestinal model (INFOGEST): oil.

The oil droplets in commercial emulsified foods have dimensions that vary widely, from hundreds of nanometers to tens of micrometers. Previously, the size of the droplets in oil-in-water emulsions has been shown to impact their gastrointestinal behavior, which may influence their physiological effects. In this study, we analyzed the impact of oil droplet diameter (0.16, 1.1 and 8.2 µm) on lipid digestion and nutraceutical bioaccessibility using a widely used standardized gastrointestinal tract model: the INFOGEST method. The emulsions used consisted of corn oil droplets stabilized using a food-grade non-ionic surfactant (Tween 20), and the droplet size was controlled by preparing them with a microfluidizer (small), sonicator (medium), or high-shear blender (large). The surfactant-coated oil droplets were relatively resistant to size changes in the mouth and stomach, due to the strong surface activity and steric stabilization mechanism of the non-ionic surfactant used. As expected, the kinetics of lipid digestion were enhanced for smaller droplets because of their greater specific surface area. The degree of lipid digestion fell from 117% to 78% (p < 0.001) as the initial droplet diameter was raised from 0.16 to 8.2 µm. In addition, there was a reduction in ß-carotene bioaccessibility from 83 to 15% (p < 0.001) with increasing droplet diameter. This result was ascribed to several effects: (i) some carotenoids were trapped inside the undigested oil phase; (ii) fewer mixed micelles were produced to internalize the carotenoids; and, (iii) a fraction of the carotenoids crystallized and sedimented. Our results underline the critical importance of considering droplet size when developing emulsified foods loaded with carotenoids. The results obtained by the INFOGEST method are consistent with those found using other in vitro methods in earlier studies.

Fluorescence Probes Exhibit Photoinduced Structural Planarization: Sensing In Vitro and In Vivo Microscopic Dynamics of Viscosity Free from Polarity Interference.

We demonstrate the construction of wavelength λ-ratiometric images that allow visualizing the distribution of microscopic dynamics within living cells and tissues by using the newly developed principle of fluorescence response. The bent-to-planar motion in the excited state of incorporated fluorescence probes leads to elongation of the π-delocalization, resulting in microviscosity-dependent but polarity-insensitive interplay between well-separated blue and red bands in emission spectra. This allows constructing the exceptionally contrasted images of cellular dynamics. Moreover, the application of probes with increased affinity toward biological membranes allowed detecting the differences in dynamics between the plasma membrane and intracellular membrane structures. Such λ-ratiometric microviscosity imaging was extended for mapping the living tissues and observing their inflammation-dependent changes.

Biphasic drug release from electrospun polyblend nanofibers for optimized local cancer treatment.

The application of the biphasic release profile furnished by electrospun polyblend nanofibers for local cancer treatment was investigated. By adjusting the weight ratio of the hydrophilic polymer (poly(ethylene oxide), PEO) and hydrophobic polymer (poly(l-lactide), PLA), PEO10-PLA90 fibers with typical biphasic release kinetics were successfully prepared. Due to their unique release profile, PEO10-PLA90 fibers can quickly access the tumor site in vivo at a high drug content within 1 h and keep at a high level for longer than two weeks. In vivo antitumor and safety studies demonstrated that PEO10-PLA90 fibers can achieve optimized local cancer treatment efficacy and avoid undesired adverse reactions. The biphasic drug release profile provided by the polyblend electrospun technology was proven to be a new conception for local chemotherapy.

Surface modification of PDMS by surface-initiated atom transfer radical polymerization of water-soluble dendronized PEG methacrylate.

The current paper reports the synthesis of a highly hydrophilic, antifouling dendronized poly(3,4,5-tris(2-(2-(2-hydroxylethoxy)ethoxy)ethoxy)benzyl methacrylate) (PolyPEG) brush using surface initiated atom transfer radical polymerization (SI-ATRP) on PDMS substrates. The PDMS substrates were first oxidized in H(2)SO(4)/H(2)O(2) solution to transform the Si-CH(3) groups on their surfaces into Si-OH groups. Subsequently, a surface initiator for ATRP was immobilized onto the PDMS surface, and PolyPEG was finally grafted onto the PDMS surface via copper-mediated ATRP. Various characterization techniques, including contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy, were used to ascertain the successful grafting of the PolyPEG brush onto the PDMS surface. Furthermore, the wettability and stability of the PDMS-PolyPEG surface were examined by contact angle measurements. Anti-adhesion properties were investigated via protein adsorption, as well as bacterial and cell adhesion studies. The results suggest that the PDMS-PolyPEG surface exhibited durable wettability and stability, as well as significantly anti-adhesion properties, compared with native PDMS surfaces. Additionally, our results present possible uses for the PDMS-PolyPEG surface as adhesion barriers and anti-fouling or functional surfaces in biomedical applications.