Handover Management in Hybrid LiFi and WiFi Networks

The hybrid LiFi and WiFi network that combines the ultra-high data transmission and ubiquitous signal coverage is a potential network scheme for the next generation of wireless networks. The handover problem in this hybrid network, however, becomes critical, due to the small cell size of the LiFi access point and the line-of-sight propagation of the optical signal. To provide accurate and timely handover decisions for the hybrid LiFi networks, I propose a few advanced handover schemes, which can significantly increase the quality of service

Surface-Engineered Graphene Navigate Divergent Biological Outcomes toward Macrophages

The “nano-bio” interface profoundly shapes the interaction between cells and nanomaterials and can even decide a cell’s fate. As a nascent two-dimensional material, graphene has many unique attributes and is proposed to be a promising candidate for biomedical applications. Thus, for graphene-based applications, it is necessary to clarify how the graphene surface navigates biological outcomes when encountering “janitorial” cells (macrophages). For this purpose, we synthesized nanographene oxide (nGO) and engineered the surface with polyethylene glycol (PEG), bovine serum albumin (BSA), and poly­(ether imide) (PEI). In contrast to pristine nGO, decoration with PEG and BSA hindered endocytosis and improved their benignancy toward macrophages. Contrarily, nGO-PEI commenced with favorable endocytosis but then suffered stagnation due to compromised macrophage viability. To unravel the underlying mechanisms regulating these diverse macrophage fates, we built a stepwise analysis. Compared to the others, nGO-PEI tended to interact electrostatically with mitochondria after their cellular internalization. Such an unexpected encounter disrupted the normal potential and integrity of mitochondria and then elicited an alteration in reactive oxygen species and cytochrome c. These responses further initiated the activation of the caspase family and ultimately dictated cells to undergo apoptosis. The advances described above will complement our knowledge of graphene functionality and serve to guide its application in biotechnological applications

Preparation of Ca-Alginate Microparticles and Its Application for Phenylketonuria Oral Therapy

Lactococcus lactis-expressing phenylalanine ammonia-lyase (LLEP) has been used to treat one of the classic genetic diseases, phenylketonuria (PKU). However, the action of stomach fluid and short residence time of LLEP at the site of absorption become the “neck” for the oral administration of LLEP. To solve these problems, pH-sensitive Ca-alginate microparticles designed as an oral administration carrier were prepared by a spray-solidification method in this study. The spray conditions influenced the size of the Ca-alginate microparticles; thus, conditions were optimized to obtain microparticles with smaller particle size for oral administration to mice. Subsequently, LLEP was encapsulated into Ca-alginate microparticles and the activity retention of LLEP released from the microparticles was examined after the microparticles passed through simulated gastric fluid. The results showed that LLEP could be well protected against simulated gastric fluid and that the final activity retention was up to 92.9%. The effects of alginate concentration on the release profile in vitro and the encapsulation efficiency (EE) were studied, and the results revealed that the microparticles possessed the highest EE and a reasonable release rate when the alginate concentration was 1.0 wt %. This alginate concentration, combined with optimized spray conditions, was used to prepare LLEP-encapsulated microparticles, and they were administered orally to mice with phenylketonuria (PKU). Compared with the groups given blank microparticles and nonencapsulated LLEP, the increase of the blood phenylalanine (Phe) level was significantly slowed after a 7 day treatment with LLEP-encapsulated microparticles. Consequently, the Ca-alginate microparticle developed by the spray-solidification method is a promising carrier of LLEP for oral administration

Preparation of Uniform Particle-Stabilized Emulsions Using SPG Membrane Emulsification

Various aspects of particle-stabilized emulsions (or so-called Pickering emulsions) have been extensively investigated during the last two decades, but the preparation of uniform Pickering emulsion droplets via a simple and scalable method has been sparingly realized. We report the preparation of uniform Pickering emulsions by Shirasu porous glass (SPG) membrane emulsification. The size of the emulsion droplets ranging from 10–50 μm can be precisely controlled by the size of the membrane pore. The emulsion droplets have a high monodispersity with coefficients of variation (CV) lower than 15% in all of the investigated systems. We further demonstrate the feasibility of locking the assembled particles at the interface, and emulsion droplets have been shown to be excellent templates for the preparation of monodisperse colloidosomes that are necessary in drug-delivery systems

TiO₂–Horseradish Peroxidase Hybrid Catalyst Based on Hollow Nanofibers for Simultaneous Photochemical–Enzymatic Degradation of 2,4-Dichlorophenol

Degradations of 2,4-dichlorophenol (2,4-DCP) using TiO2/UV photochemical and horseradish peroxidase (HRP) enzymatic treatments, as well as simultaneous photochemical–enzymatic treatments, by combining these two processes were systematically investigated and compared. When free HRP was used in the simultaneous process, a negative synergetic effect was observed due to serious inactivation of the HRP caused by UV irradiation in the presence of TiO2. A hybrid catalyst system was then developed by in situ encapsulating HRP inside nanochambers of TiO2-doped hollow nanofibers through coaxial electrospinning. Such encapsulation effectively avoided UV-induced deactivation of the enzymes, thus the 2,4-DCP degradation efficiency was improved significantly as compared with the that using HRP or TiO2/UV either separately or simultaneously in free formation. Furthermore, the higher the concentration of 2,4-DCP, the more remarkable the enhancement achieved, such that a 90% removal ratio was obtained within only 3 h for the degradation of 10 mM 2,4-DCP using the integrated TiO2–HRP hybrid catalyst system. While the removal ratio obtained with dispersed TiO2/UV, TiO2 doped in PU hollow nanofibers, free HRP, combination of dispersed TiO2 and free HRP under UV, as well as the encapsulated HRP, were only 31.37%, 27.98%, 49.71%, 36.53%, and 58.32%, respectively. The hybrid catalysts system also showed excellent recycling capability and thermal stability

Acid-Responsive Immune-Enhancing Chitosan Formulation Capable of Transforming from Particle Stabilization to Polymer Chain Stabilization

Chitosan with pH sensitivity and biocompatibility was selected to prepare chitosan nanoparticle-stabilized Pickering emulsion (CSPE). The flexibility of CSPE enables stress deformation when in contact with cell membranes, thereby mimicking the deformability of natural pathogens and facilitating their efficient uptake by cells. In the acidic environment of lysosomes, the amino groups of chitosan molecules are protonated, and the water solubility increases. CSPE transforms from particle-stabilized to polymer chain-stabilized, its subsequent swelling and proton accumulation lead to lysosome rupture. The experimental results evaluating CSPE as an adjuvant shows that CSPE could efficiently load antigens, promote endocytosis and antigen cross-presentation, recruit antigen-presenting cells at the injection site, boost T-cell activation, and enhance both humoral and cellular immune responses. In the prophylactic and therapeutic tumor models of E.G7-OVA lymphoma and B16-MUC1 melanoma, CSPE significantly inhibited tumor growth and prolonged the survival of mice. In summary, antigenic lysosomal escape resulted from the chitosan molecular state transition is the key to the enhancement of cellular immunity by CSPE, and CSPE is a promising vaccine adjuvant

Carrier-Free, Chemophotodynamic Dual Nanodrugs via Self-Assembly for Synergistic Antitumor Therapy

There are tremendous challenges from both tumor and its therapeutic formulations affecting the effective treatment of tumor, including tumor recurrence, and complex multistep preparations of formulation. To address these issues, herein a simple and green approach based on the self-assembly of therapeutic agents including a photosensitizer (chlorine e6, Ce6) and a chemotherapeutic agent (doxorubicin, DOX) was developed to prepare carrier-free nanoparticles (NPs) with the ability to inhibit tumor recurrence. The designed NPs were formed by self-assembly of Ce6 and DOX associated with electrostatic, π–π stacking and hydrophobic interactions. They have a relatively uniform size of average 70 nm, surface charge of −20 mV and high drug encapsulation efficiency, which benefits the favorable accumulation of drugs at the tumor region through a potential enhanced permeability and retention (EPR) effect as compared to their counterpart of free Ce6 solution. In addition, they could eradiate tumors without recurrence in a synergistic way following one treatment cycle. Furthermore, the NPs are safe without any activation of inflammation or immune response in separated organs. Taken together, the rationale of these pure nanodrugs via the self-assembly approach might open an alternative avenue and give inspiration to fabricate new carrier-free nanodrugs for tumor theranostics, especially for two small molecular antitumor drugs with the aim of combinational antitumor therapy in a synergistic way

Interfacial Cohesion and Assembly of Bioadhesive Molecules for Design of Long-Term Stable Hydrophobic Nanodrugs toward Effective Anticancer Therapy

The majority of anticancer drugs are poorly water-soluble and thus suffer from rather low bioavailability. Although a variety of delivery carriers have been developed for bioavailability improvement, they are severely limited by low drug loading and undesired side effects. The optimum delivery vehicle would be a biocompatible and biodegradable drug nanoparticle of uniform size with a thin but stable shell, making it soluble, preventing aggregation and enabling targeting. Here, we present a general strategy for the rational design of hydrophobic drug nanoparticles with high drug loading by means of interfacial cohesion and supramolecular assembly of bioadhesive species. We demonstrate that the pathway is capable of effectively suppressing and retarding Ostwald ripening, providing drug nanoparticles with small and uniform size and long-term colloidal stability. The final complex drug nanoparticles provide higher tumor accumulation, negligible toxicity, and enhanced antitumor activity, superior to commercial formulations. Our findings demonstrate that local, on-demand coating of hydrophobic nanoparticles is achievable through cooperation and compromise of interfacial adhesion and assembly

Phenyl Linker-Induced Dense PEG Conformation Improves the Efficacy of C‑Terminally MonoPEGylated Staphylokinase

PEGylation can improve the protein efficacy by prolonging serum half-life and reducing proteolytic sensitivity and immunogenicity. However, PEGylation may decrease the bioactivity of a protein by interfering with binding of its substrate or receptors. Here, staphylokinase (SAK), a thrombolysis agent for therapy of myocardial infarction, was mono-PEGylated at the C-terminus of SAK far from its bioactive domain. Phenyl, propyl, and amyl moieties were used as linkers between SAK and polyethylene glycol (PEG), respectively. Flexible propyl and amyl linkers lead to loose conformation. In contrast, rigid and hydrophobic phenyl linker induces dense PEG conformation that can extensively shield most domains adjacent to C-terminus (e.g., the antigen epitopes and proteolytic sites) of SAK and inefficiently shield its bioactive domain. As compared with loose PEG conformation, dense PEG conformation is more efficient to maintain the bioactivity, increase the plasma half-life, and decrease the proteolytic sensitivity and immunogenicity of the PEGylated SAK

Single-Chromophore-Based Therapeutic Agent Enables Green-Light-Triggered Chemotherapy and Simultaneous Photodynamic Therapy to Cancer Cells

A new type of single-chromophore-based photoactivatable prodrug (B-Cbl-3) enabling green-light-triggered chemotherapy and simultaneous photodynamic therapy with superb therapeutic efficacy was developed by conjugating a photoactive BODIPY derivative with an antitumor chlorambucil moiety. The optimized BODIPY moiety markedly enabled high efficient photogeneration of 1O2 and fluorescence emission with distinct colors before and after photorelease of chlorambucil. The preliminary biological experiment results have verified the efficient photorelease of chlorambucil from B-Cbl-3 and the huge contrast in cytotoxicity between them, superior combined therapeutic performance based on extraordinary low doses of drug and light irradiation, and ratiometric fluorescence imaging for in situ monitoring drug release. The salient superiority of B-Cbl-3 regarding alleviating the attenuation of triggering light caused by optically turbid tissue that short-wavelength lights typically encounters has also been verified