Tailored Polypyrrole Nanofibers as Ion-to-Electron Transduction Membranes for Wearable K+ Sensors.

Conductive polymers are recognized as ideal candidates for the development of noninvasive and wearable sensors for real-time monitoring of potassium ions (K+) in sweat to ensure the health of life. However, the low ion-to-electron transduction efficiency and limited active surface area hamper the development of high-performance sensors for low-concentration K+ detection in the sweat. Herein, a wearable K+ sensor is developed by tailoring the nanostructure of polypyrrole (PPy), serving as an ion-to-electron transduction layer, for accurately and stably tracing the K+ fluctuation in human sweat. The PPy nanostructures can be tailored from nanospheres to nanofibers by controlling the supramolecular assembly process during PPy polymerization. Resultantly, the ion-to-electron transduction efficiency (17-fold increase in conductivity) and active surface area (1.3-fold enhancement) are significantly enhanced, accompanied by minimized water layer formation. The optimal PPy nanofibers-based K+ sensor achieved a high sensitivity of 62 mV decade-1, good selectivity, and solid stability. After being integrated with a temperature sensor, the manufactured wearable sensor realized accurate monitoring of K+ fluctuation in the human sweat.

Efficacy of epi-1 modified epirubicin and curcumin encapsulated liposomes targeting-EpCAM in the inhibition of epithelial ovarian cancer cells.

Treatment of epithelial ovarian cancer (EOC) is a challenge because it still leads to unsatisfactory clinical prognosis. This is due to the toxicity and poor targeting of chemotherapeutic agents, as well as metastasis of the tumor. In this study, we designed a targeted liposome with nanostructures to overcome these problems. In the liposomes, epirubicin and curcumin were encapsulated to achieve their synergistic antitumor efficacy, while Epi-1 was modified on the liposomal surface to target epithelial cell adhesion molecule (EpCAM). Epi-1, a macrocyclic peptide, exhibits active targeting for enhanced cellular uptake and potent cytotoxicity against tumor cells. The encapsulation of epirubicin and curcumin synergistically inhibited the formation of neovascularization and vasculogenic mimicry (VM) channels, thereby suppressing tumor metastasis on SKOV3 cells. The dual drug loaded Epi-1-liposomes also induced apoptosis and downregulated metastasis-related proteins for effective antitumor in vitro. In vivo studies showed that dual drug loaded Epi-1-liposomes prolonged circulation time in the blood and increased the selective accumulation of drug at the tumor site. H&E staining and immunohistochemistry with Ki-67 also showed that targeted liposomes elevated antitumor activity. Also, targeted liposomes downregulated angiogenesis-related proteins to inhibit angiogenesis and thus tumor metastasis. In conclusion, the production of dual drug loaded Epi-1-liposomes is an effective strategy for the treatment of EOC.

Application of Duplex Droplet Digital PCR Detection of miR-888 and miR-891a in Semen Identification.

OBJECTIVES: To establish a system for simultaneous detection of miR-888 and miR-891a by droplet digital PCR (ddPCR), and to evaluate its application value in semen identification. METHODS: The hydrolysis probes with different fluorescence modified reporter groups were designed to realize the detection of miR-888 and miR-891a by duplex ddPCR. A total of 75 samples of 5 body fluids (including peripheral blood, menstrual blood, semen, saliva and vaginal secretion) were detected. The difference analysis was conducted by Mann-Whitney U test. The semen differentiation ability of miR-888 and miR-891a was evaluated by ROC curve analysis and the optimal cut-off value was obtained. RESULTS: There was no significant difference between the dual-plex assay and the single assay in this system. The detection sensitivity was up to 0.1 ng total RNA, and the intra- and inter-batch coefficients of variation were less than 15%. The expression levels of miR-888 and miR-891a detected by duplex ddPCR in semen were both higher than those in other body fluids. ROC curve analysis showed that the AUC of miR-888 was 0.976, the optimal cut-off value was 2.250 copies/µL, and the discrimination accuracy was 97.33%; the AUC of miR-891a was 1.000, the optimal cut-off value was 1.100 copies/µL, and the discrimination accuracy was 100%. CONCLUSIONS: In this study, a method for detection of miR-888 and miR-891a by duplex ddPCR was successfully established. The system has good stability and repeatability and can be used for semen identification. Both miR-888 and miR-891a have high ability to identify semen, and the discrimination accuracy of miR-891a is higher.

Development and characterization of octreotide-modified curcumin plus docetaxel micelles for potential treatment of non-small-cell lung cancer.

We prepared octreotide (OCT)-modified curcumin plus docetaxel micelles to enhance active targeting and inhibit tumor metastasis by destroying vasculogenic mimicry (VM) channels. Soluplus was applied as an amphiphilic material to form micelles via film dispersion. The cytotoxic effects, active cellular targeting, and inhibitory effects on metastasis were systematically evaluated in vitro using A549 cells, and in vivo antitumor effects were evaluated using xenograft tumor-bearing mice. In vitro assays indicated that the OCT-modified curcumin plus docetaxel micelles showed robust cytotoxicity on A549 cells and effectively inhibited VM channels and tumor metastasis. Studying the mechanism of action indicated that OCT-modified curcumin plus docetaxel micelles downregulated MMP-2 and HIF-1α. In vivo assays indicated that OCT-modified curcumin plus docetaxel micelles increased drug accumulation at tumor sites and showed obvious antitumor efficacy. The developed OCT-modified curcumin plus docetaxel micelles may offer a promising treatment strategy for non-small-cell lung cancer.

Characterization of a Thermoresponsive Chitosan Derivative as a Potential Draw Solute for Forward Osmosis.

A thermoresponsive chitosan derivative was synthesized by reacting chitosan (CS) with butyl glycidyl ether (BGE) to break the inter- and intramolecular hydrogen bonds of the polymer. An aqueous solution of the thermoresponsive CS derivative exhibits a lower critical solution temperature (LCST) than CS, and it undergoes a phase transition separation when the temperature changes. Successful incorporation of BGE into the CS was confirmed by FTIR and XPS analyses. Varying the BGE content and the concentration of the aqueous solution produced different LCST ranges, as shown by transmittance vs temperature curves. The particle size was observed by scanning electron microscopy, which revealed that the particles were smaller and well dispersed at 15 °C, whereas the particles became larger and tended to aggregate at 60 °C. A similar trend was observed with the mean particle size measured using dynamic light scattering. Positron annihilation lifetime spectroscopy data also revealed the reversibility of the particle properties as a function of temperature. Microstructure analysis showed that the particles had larger free-volume sizes at 15 °C than at 60 °C. The particles were also found to be nontoxic with 92% cell survival. A simple forward osmosis (FO) test for dye dehydration revealed the potential use of the thermoresponsive chitosan derivative as a draw solute with a flux of 8.6 L/m2 h and rejection of 99.8%.

Structuring and Shaping of Mechanically Robust and Functional Hydrogels toward Wearable and Implantable Applications.

Hydrogels possess unique features such as softness, wetness, responsiveness, and biocompatibility, making them highly suitable for biointegrated applications that have close interactions with living organisms. However, conventional man-made hydrogels are usually soft and brittle, making them inferior to the mechanically robust biological hydrogels. To ensure reliable and durable operation of biointegrated wearable and implantable devices, mechanical matching and shape adaptivity of hydrogels to tissues and organs are essential. Recent advances in polymer science and processing technologies have enabled mechanical engineering and shaping of hydrogels for various biointegrated applications. In this review, polymer network structuring strategies at micro/nanoscales for toughening hydrogels are summarized, and representative mechanical functionalities that exist in biological materials but are not easily achieved in synthetic hydrogels are further discussed. Three categories of processing technologies, namely, 3D printing, spinning, and coating for fabrication of tough hydrogel constructs with complex shapes are reviewed, and the corresponding hydrogel toughening strategies are also highlighted. These developments enable adaptive fabrication of mechanically robust and functional hydrogel devices, and promote application of hydrogels in the fields of biomedical engineering, bioelectronics, and soft robotics.

The feasibility and safety of biomaterials for posterior scleral reinforcement in rabbits.

To explore the feasibility and safety of biomaterials for posterior scleral reinforcement (PSR) in rabbits. Decellularization and genipin crosslink were applied to the fresh bovine pericardium and porcine endocranium, and then mechanical properties, suture retention strength, and stability were tested. PSR operation was performed on 24 rabbit eyes using treated biological materials. Ophthalmic examination was performed regularly before and after PSR operation (1 week, 1 month, 3 months, 6 months). To evaluate the effectiveness, A ultrasound, diopter, and optical coherence tomography were conducted. General condition, fundus photograph, and pathological examination were recorded to evaluate the safety. Compared with genipin crosslinked bovine pericardium (Gen-BP) (21.29 ± 13.29 Mpa), genipin crosslinked porcine endocranium (Gen-PE) (34.85 ± 3.67 Mpa,P< 0.01) showed a closer elastic modulus to that of genipin crosslinked human sclera. There were no complications or toxic reactions directly related to the materials. Capillary hyperplasia, inflammatory cell infiltration, and collagen fiber deposition were observed, and the content of type I collagen fibers increased after PSR. Overall, the choroidal thickness of treated eyes was significantly thickened at different time points after PSR, which were 96.84 ± 21.08 µm, 96.72 ± 22.00 µm, 90.90 ± 16.57 µm, 97.28 ± 14.74 µm, respectively. The Gen-PE group showed changes that were almost consistent with the overall data. Gen-BP and Gen-PE are safe biological materials for PSR. The Gen-PE group demonstrated more significant advantages over the Gen-BP group in terms of material properties.

Microstructure optimization of bioderived polyester nanofilms for antibiotic desalination via nanofiltration.

The successful implementation of thin-film composite membranes (TFCM) for challenging solute-solute separations in the pharmaceutical industry requires a fine control over the microstructure (size, distribution, and connectivity of the free-volume elements) and thickness of the selective layer. For example, desalinating antibiotic streams requires highly interconnected free-volume elements of the right size to block antibiotics but allow the passage of salt ions and water. Here, we introduce stevioside, a plant-derived contorted glycoside, as a promising aqueous phase monomer for optimizing the microstructure of TFCM made via interfacial polymerization. The low diffusion rate and moderate reactivity of stevioside, together with its nonplanar and distorted conformation, produced thin selective layers with an ideal microporosity for antibiotic desalination. For example, an optimized 18-nm membrane exhibited an unprecedented combination of high water permeance (81.2 liter m-2 hour-1 bar-1), antibiotic desalination efficiency (NaCl/tetracycline separation factor of 11.4), antifouling performance, and chlorine resistance.

Phosphonium Modification Leads to Ultrapermeable Antibacterial Polyamide Composite Membranes with Unreduced Thickness.

Water transport rate in network membranes is inversely correlated to thickness, thus superior permeance is achievable with ultrathin membranes prepared by complicated methods circumventing nanofilm weakness and defects. Conferring ultrahigh permeance to easily prepared thicker membranes remains challenging. Here, a tetrakis(hydroxymethyl) phosphonium chloride (THPC) monomer is discovered that enables straightforward modification of polyamide composite membranes. Water permeance of the modified membrane is ≈6 times improved, give rising to permeability (permeance × thickness) one magnitude higher than state-of-the-art polymer nanofiltration membranes. Meanwhile, the membrane exhibits good rejection (RNa2SO4 = 98%) and antibacterial properties under crossflow conditions. THPC modification not only improves membrane hydrophilicity, but also creates additional angstrom-scale channels in polyamide membranes for unimpeded transport of water. This unique mechanism provides a paradigm shift in facile preparation of ultrapermeable membranes with unreduced thickness for clean water and desalination.

Preparation and properties of PEC nanocomposite membranes with carboxymethyl cellulose and modified silica.

Carboxymethyl cellulose (CMC)-modified silica nanocomposites were prepared via in situ incorporation of modified silica during the ionic complexation between CMC and poly(2-methacryloyloxy ethyl trimethylammonium chloride) (PDMC). Ionic bonds were introduced between the poly(2-acrylamido-2-methylproanesulfonic acid) modified silica (SiO2-PAMPS) and the polyelectrolyte complex (PEC) matrix. The PEC nanocomposites (PECNs) and their membranes (PECNMs) were characterized with Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile testing. PECNM containing 5 wt.% SiO2-PAMPS showed a tensile strength of 68 MPa and elongation at break of 7.1%, which were 1.9 and 2.6 times as high as those of pristine PEC membranes, respectively. Moreover, the pervaporation performance of as-prepared PECNMs was evaluated with dehydration of 10 wt.% aqueous isopropanol mixtures, and the PECNMs exhibited a flux of 2,400 gm(-2)h(-1) with a high separation factor of 4491 at 70°C.

Tuning nanostructure of graphene oxide/polyelectrolyte LbL assemblies by controlling pH of GO suspension to fabricate transparent and super gas barrier films.

A technique of layer-by-layer (LbL) self-assembly was used to prepare transparent multilayered gas barrier films consisting of graphene oxide (GO)/branched poly(ethylenimine) (BPEI) on a poly(ethylene terephthalate) substrate. The effect of the GO suspension pH on the nanostructure and oxygen barrier properties of the GO/BPEI film was investigated. The oxygen barrier properties of the assemblies were shown to be highly dependent on the pH. It was demonstrated that the film assemblies prepared using a GO suspension with a pH of 3.5 exhibited very dense and ordered structures and delivered very low oxygen transmission rates (the lowest was <0.05 cm(3) m(-2) day(-1)). The assemblies were characterized with ultraviolet-visible spectroscopy and ellipsometry to identify the film growth mechanism, and the result indicated a linear growth behavior. To analyze the nanostructure of the films, atomic force microscopy, transmission electronic microscopy, and grazing incidence wide-angle X-ray diffraction were used.