Oral delivery of insulin with intelligent glucose-responsive switch for blood glucose regulation.

BACKGROUND: The traditional treatment for diabetes usually requires frequent insulin injections to maintain normoglycemia, which is painful and difficult to achieve blood glucose control. RESULTS: To solve these problems, a non-invasive and painless oral delivery nanoparticle system with bioadhesive ability was developed by amphipathic 2-nitroimidazole-L-cysteine-alginate (NI-CYS-ALG) conjugates. Moreover, in order to enhance blood glucose regulation, an intelligent glucose-responsive switch in this nanoparticle system was achieved by loading with insulin and glucose oxidase (GOx) which could supply a stimulus-sensitive turnover strategy. In vitro tests illustrated that the insulin release behavior was switched "ON" in response to hyperglycemic state by GOx catalysis and "OFF" by normal glucose levels. Moreover, in vivo tests on type I diabetic rats, this system displayed a significant hypoglycemic effect, avoiding hyperglycemia and maintaining a normal range for up to 14 h after oral administration. CONCLUSION: The stimulus-sensitive turnover strategy with bioadhesive oral delivery mode indicates a potential for the development of synthetic GR-NPs for diabetes therapy, which may provide a rational design of proteins, low molecular drugs, as well as nucleic acids, for intelligent releasing via the oral route.

A carboxymethyl lentinan layer by layer self-assembly system as a promising drug chemotherapeutic platform.

Surface functionalization of mesoporous silica nanoparticles (MSNs) has been proposed as an efficient strategy for enhancing the biocompatibility and efficiency of an MSN-based carrier platform. Herein, natural polyelectrolyte multilayers composed of poly-l-ornithine (PLO) and carboxymethyl lentinan (LC) were coated on the surface of MSNs through a layer-by-layer (LbL) self-assembly technique, and were characterized by ζ-potential, FTIR, 13C NMR, SEM, TEM, XRD, and TG. The prepared carrier presented alternating positive and negative potentials when coated with the polyelectrolytes, and the surface of MSN-PLO/LC was rougher compared to the naked MSNs. The biocompatibility tests, including cytocompatibility, hemocompatibility, and histocompatibility, showed that MSNs biocompatibility could be improved by modifying LC. A high loading and sustained release drug delivery system was constructed after loading doxorubicin (DOX) into the prepared MSN-PLO/LC, which exhibited significant anti-proliferative efficiency in human cervical cancer cell lines (Hela). Therefore, the PLO/LC LbL NPs (layer-by-layer self-assembled nanoparticles coated with PLO/LC layers) based on MSNs, which is easily prepared by electrostatic interactions, can be considered a promising drug chemotherapeutic platform and delivery technique for future human cervical cancer therapy.

Bioinspired red blood cell membrane-encapsulated biomimetic nanoconstructs for synergistic and efficacious chemo-photothermal therapy.

Recently, the fabrication of nanotechnology-based co-delivery systems has garnered enormous interest for efficacious cancer therapy. However, these systems still face certain challenges such as codelivery of drugs with different chemistries, inadequate loading efficiency, immune rejection resulting in rapid clearance and substantially poor bioavailability in vivo. To address the challenges, we have developed a biomimetic and stable design based on bovine serum albumin (BSA) nanoparticles that are encapsulated with a hydrophilic photothermal agent, indocyanine green (ICG), as well as a hydrophobic agent, gambogic acid (GA), via the desolvation method. Furthermore, these nanoconstructs have been coated with the red blood cell membranes (RBCm), which exhibit pronounced long-term circulation in addition to avoiding premature leakage of drugs. RBCm-coated BSA nanoparticles show a higher affinity towards both GA and ICG (RmGIB NPs), resulting in high loading efficiencies of 24.3 ±â€¯1.2 % and 25.0 ±â€¯1.2 %, respectively. Moreover, the bio-efficacy investigations of these biomimetic constructs (RmGIB NPs) in cells in vitro as well as in tumor-bearing mice in vivo confirm augmented inhibition, demonstrating potential synergistic chemo-photothermal therapeutic efficacy. Altogether, we provide an efficient delivery platform for designing and constructing BSA nanovehicles toward synergistic and effective co-delivery of therapeutics.

The Influence of bFGF on the Fabrication of Microencapsulated Cartilage Cells under Different Shaking Modes.

Cell encapsulation in hydrogels has been extensively used in cytotherapy, regenerative medicine, 3D cell culture, and tissue engineering. Herein, we fabricated microencapsulated cells through microcapsules loaded with C5.18 chondrocytes alginate/chitosan prepared by a high-voltage electrostatic method. Under optimized conditions, microencapsulated cells presented uniform size distribution, good sphericity, and a smooth surface with different cell densities. The particle size distribution was determined at 150⁻280 µm, with an average particle diameter of 220 µm. The microencapsulated cells were cultured under static, shaking, and 3D micro-gravity conditions with or without bFGF (basic fibroblast growth factor) treatment. The quantified detection (cell proliferation detection and glycosaminoglycan (GAG)/type II collagen (Col-II)) content was respectively determined by cell counting kit-8 assay (CCK-8) and dimethylmethylene blue (DMB)/Col-II secretion determination) and qualitative detection (acridine orange/ethidium bromide, hematoxylin-eosin, alcian blue, safranin-O, and immunohistochemistry staining) of these microencapsulated cells were evaluated. Results showed that microencapsulated C5.18 cells under three-dimensional microgravity conditions promoted cells to form large cell aggregates within 20 days by using bFGF, which provided the possibility for cartilage tissue constructs in vitro. It could be found from the cell viability (cell proliferation) and synthesis (content of GAG and Col-II) results that microencapsulated cells had a better cell proliferation under 3D micro-gravity conditions using bFGF than under 2D conditions (including static and shaking conditions). We anticipate that these results will be a benefit for the design and construction of cartilage regeneration in future tissue engineering applications.

Poly-allylamine hydrochloride and fucoidan-based self-assembled polyelectrolyte complex nanoparticles for cancer therapeutics.

Herein, we fabricated the novel drug delivery system based on the self-assembly of two polyelectrolytes, poly-allylamine hydrochloride (PAH) and fucoidan, as the polycation and polyanion, respectively, under mild conditions for cancer therapeutics. Furthermore, the designed polyelectrolyte complex nanoparticles as well as the methotrexate (MTX) disodium salt-loaded composites were systematically characterized using various techniques. The MTX loading in the nanoparticles was confirmed by zeta potential values that changed from -36.2 ± 2.2 to -28.3 ± 3.1 mV at a loading amount of 13.3 ± 1.2%. Furthermore, the obtained eventual particle sizes of nanoparticles were various with different concentrations and ratios of polyelectrolytes. The particle size also has increased from 130 ± 2.6 to 162.9 ± 2.3 nm after loading MTX. The drug release investigations in vitro at a pH value of 6.0 (acid environment) showed that the release of MTX was sustained in the conditions provided. Finally, we investigated the anticancer efficacy of MTX-loaded nanoparticles on MCF-7 cells and HeLa cells and the satisfactory results were obtained. Together, these self-assembled PAH/fucoidan nanoparticles with sustained drug release property will become the promising delivery system for cancer therapeutics. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 339-347, 2019.

Primary biocompatibility tests of poly(lactide-co-glycolide)-(poly-L-orithine/fucoidan) core-shell nanocarriers.

Layer-by-layer (LbL) self-assembly is the technology used in intermolecular static electricity, hydrogen bonds, covalent bonds and other polymer interactions during film assembling. This technology has been widely studied in the drug carrier field. Given their use in drug delivery systems, the biocompatibility of these potential compounds should be addressed. In this work, the primary biocompatibility of poly(lactide-co-glycolide)-(poly-L-orithine/fucoidan) [PLGA-(PLO/fucoidan)] core-shell nanoparticles (NPs) was investigated. Atomic force microscopy revealed the PLGA-(PLO/Fucoidan)4 NPs to be spherical, with a uniform size distribution and a smooth surface, and the NPs were stable in physiological saline. The residual amount of methylene chloride was further determined by headspace gas chromatography, in which the organic solvent can be volatilized during preparation. Furthermore, cell viability, acridine orange/ethidium bromide staining, haemolysis and mouse systemic toxicity were all assessed to show that PLGA-(PLO/fucoidan)4 NPs were biocompatible with cells and mice. Therefore, these NPs are expected to have potential applications in future drug delivery systems.

Bacterial magnetosomes-based nanocarriers for co-delivery of cancer therapeutics in vitro.

In recent times, co-delivery of therapeutics has emerged as a promising strategy for treating dreadful diseases such as cancer. MATERIALS AND METHODS: In this study, we developed a novel nanocarrier based on bacterial magnetosomes (BMs) that co-loaded with siRNA and doxorubicin (DOX) using polyethyleneimine (PEI) as a cross-linker (BMs/DP/siRNA). The delivery efficiency of siRNA as well as the pH-responsive release of DOX, and synergistic efficacy of these therapeutics in vitro were systematically investigated. RESULTS: The structure of DOX-PEI (DP) conjugates that synthesized via hydrazone bond formation was confirmed by 1H nuclear magnetic resonance (NMR). The in vitro release experiments showed that the DP conjugate (DOX-loading efficiency - 5.77%±0.08%) exhibited the long-term release behavior. Furthermore, the optimal BMs/DP/siRNA particle size of 107.2 nm and the zeta potential value of 31.1±1.0 mV facilitated enhanced cellular internalization efficiency. Moreover, the agarose gel electrophoresis showed that the co-delivery system could protect siRNA from degradation in serum and RNase A. In addition, the cytotoxicity assay showed that BMs/DP/siRNA could achieve an excellent synergistic effect compared to that of siRNA delivery alone. The acridine orange (AO)/ethidium bromide (EB) double staining assay also showed that BMs/DP/siRNA complex could induce cells in a stage of late apoptosis and nanocomplex located in the proximity of the nucleus. CONCLUSION: The combination of gene and chemotherapeutic drug using BMs is highly efficient, and the BMs/DP/siRNA would be a promising therapeutic strategy for the future therapeutics.