Ruimin Long

A Natural Bacterium-Produced Membrane-Bound Nanocarrier for Drug Combination Therapy

To minimize the non-specific toxicity of drug combination during cancer therapy, we prepared a new system synthesized from bacteria to deliver the anticancer drugs cytosine arabinoside (Ara-C) and daunorubicin (DNR). In this study, we selected genipin (GP) and poly-l-glutamic acid (PLGA) as dual crosslinkers. Herewith, we demonstrated the preparation, characterization and in vitro antitumor effects of Ara-C and DNR loaded GP-PLGA-modified bacterial magnetosomes (BMs) (ADBMs-P). The results show that this new system is stable and exhibits optimal drug-loading properties. The average diameters of BMs and ADBMs-P were 42.0 ± 8.6 nm and 65.5 ± 8.9 nm, respectively, and the zeta potential of ADBMs-P (−42.0 ± 6.4 mV) was significantly less than that of BMs (−28.6 ± 7.6 mV). The optimal encapsulation efficiency and drug loading of Ara-C were 68.4% ± 9.4% and 32.4% ± 2.9%, respectively, and those of DNR were 36.1% ± 2.5% and 17.9% ± 1.6%. Interestingly, this system also exhibits long-term release behaviour sequentially, without an initial burst release. The Ara-C drug continued to release about 85% within 40 days, while DNR release lasted only for 13 days. Moreover, similar to free drugs, ADBMs-Ps are strongly cytotoxic to cancer cells in vitro (HL-60 cells), with the inhibition rate approximately 96%. This study reveals that this new system has a potential for drug delivery application in the future, especially for combination therapy.

Synthesis and characterization of innovative poly(lactide-co-glycolide)-(poly-L-ornithine/fucoidan) core–shell nanocarriers by layer-by-layer self-assembly

Layer-by-Layer (LbL) self-assembly of nanocarriers has garnered the interest of researchers for a wide variety of biomedical applications. In this study, we demonstrated the preparation of poly(lactide-co-glycolide) (PLGA)-(poly-L-ornithine (PLO)/fucoidan)4 core–shell nanoparticles (LbL NPs) by a LbL-based self-assembly process, which possessed a mean size of 170 nm. In LbL NPs, a drug carrying PLGA nano-core is coated with alternating PLO and sulfated polysaccharide fucoidan composite films as a shell on the surface. The anti-tumor drug doxorubicin (DOX) loaded into the PLGA core, resulted in better encapsulation efficiency and its in vitro release from LbL NPs demonstrates that this core–shell strategy takes an advantage of its ability to hold the drug cargo and exhibit controlled release. Further, in vitro cell uptake studies by confocal laser scanning microscopy (CLSM) examination in breast tumor cells (MCF-7 cell line) have confirmed that the nanocarriers are successfully internalized and outlined their presence in the cytoplasm after 4 h of incubation. These intracellularly delivered DOX-loaded LbL NPs exhibited significant anti-tumor activity against breast tumor cells. This innovative chemotherapeutic design taking above advantages of successful internalization along with controlled release property signifies as a promising interventional therapeutic delivery system.

Preparation of a MVL-Ca-Alg/CS MEMs system with add-on effect for type 2 diabetes treatment

ABSTRACT Add-on drugs, often called as synergistic therapy, for diabetes have been comparatively more promising as they can reduce the systemic adverse effects resulted during respective monotherapy [metformin (MET)/insulin (INS)]. Herewith, we formulated a multivesicular liposome microparticles-embedded Ca-Alg/chitosan microcapsules (MVL-Ca-Alg/CS MEMs) system by a double-emulsion method using a high voltage electrostatic droplet generator. Physical characterization of the designed formulation was elucidated based on particle size and distribution, drug loading and encapsulation efficiency, drug delivery properties, and pharmacodynamic evaluation. The multivesicular liposomes microparticles (MVLs MPs) and MVL-Ca-Alg/CS MEMs have shown good sphericity and dispersion, and the average diameters were 37 and 491 µm, respectively. The confocal laser scanning microscopic observations demonstrated that fluorescein isothiocyanate-conjugated INS is uniformly dispersed in MVLs MPs, predominantly within the lumen of the polycystic liposome. This multicomponent system possessing INS in the inner space and MET at the outer space resulted in orderly and sustained drug release patterns. Furthermore, the obtained in vivo experimental data have shown that the designed MEMs system resulted in significantly higher hypoglycemic effect compared to pure INS, demonstrating that our multicomponent design has an enormous potential for treating diabetes. GRAPHICAL ABSTRACT

Co-microencapsulation of BMSCs and mouse pancreatic β cells for improving the efficacy of type I diabetes therapy

Introduction To overcome the shortcomings of pancreas transplantation and insulin injection treatment for type I diabetes, biocompatible materials were used to prepare alginate-chitosan-alginate microcapsules that co-encapsulated bone marrow mesenchymal stem cells and mouse pancreatic β cells to treat diabetic mice. Methods Blank alginate-chitosan-alginate (ACA) microcapsules and co-microencapsulated cells were prepared using a high-voltage electrostatic method and then characterized using an inverted microscope. Cell viability was evaluated using AO/EB staining. ELISA kit was used to detect insulin secretion. Peri-orbital blood samples were obtained from the mice for blood glucose determination every week for one month. Results After 28 days of in vitro culture, the secretion of insulin following co-microencapsulation was higher than that observed for microencapsulated beta-TC-6 cells alone. On the 28th day after transplantation, the blood glucose level was 6.86 mmol/L in the microencapsulated beta-TC-6 group. On the 14th day, the blood glucose level was 6.80 mmol/L in the co-microencapsulated BMSC/beta-TC-6 group, which was close to the normal blood glucose level of healthy mice. These results indicated that the efficacy in reducing blood glucose was better in the co-microencapsulated BMSC/beta-TC-6 group. Conclusions This primary study indicated that combining microencapsulation technology and co-culture of stem cells and somatic cells shows promise for the treatment of type I diabetes mellitus.

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.

Poly-L-ornithine/fucoidan-coated calcium carbonate microparticles by layer-by-layer self-assembly technique for cancer theranostics

Recently, the layer-by-layer (LbL) self-assembly technology has attracted the enormous interest of researchers in synthesizing various pharmaceutical dosage forms. Herewith, we designed a biocompatible drug delivery system containing the calcium carbonate microparticles (CaCO3 MPs) that coated with the alternatively charged polyelectrolytes, i.e., poly-L-ornithine (PLO)/fucoidan by LbL self-assembly process (LbL MPs). Upon coating with the polyelectrolytes, the mean particle size of MPs obtained from SEM observations increased from 1.91 to 2.03 μm, and the surface of LbL MPs was smoothened compared to naked CaCO3 MPs. In addition, the reversible zeta potential changes have confirmed the accomplishment of layer upon a layer assembly. To evaluate the efficiency of cancer therapeutics, we loaded doxorubicin (Dox) in the LbL MPs, which resulted in high (69.7%) drug encapsulation efficiency. The controlled release of Dox resulted in the significant antiproliferative efficiency in breast cancer cell line (MCF-7 cells), demonstrating the potential of applying this innovative drug delivery system in the biomedical field.

The influence of spatial distribution on add-on therapy of designed Ca-Alg/CS MEMs system

Abstract To improve the efficacy and reduce the systemic toxicity of the diabetes mellitus, herewith, we developed a novel microparticles-embedded microcapsules (MEMs) system, synthesized from calcium alginate/chitosan (Ca-Alg/CS), by emulsion gelation using a high voltage electrostatic droplet generator. In our study, we selected two antidiabetic drugs insulin (INS) and metformin (MET) as model drugs to investigate different spatial distribution appropriate of MEMs system. Characterization based on particle size and morphology, encapsulation efficiency and drug loading, as well as drug delivery properties were carried out on the MEMs system. Typical multi-chamber structure was shown by SEM and the optical spectra. The average diameters of microparticles and Ca-Alg/CS MEMs were 2100 nm and 410 μm, respectively. Insulin and MET were embedded into MEMs via electrostatic reaction according to FT-IR spectra. Moreover, drug loading and encapsulation efficiency of INS were higher than that of MET in this system when drugs were loaded alone or together. More importantly, this system has potential for orderly drug release and well sustained release when MET in the inner and INS in the outer space could be applied as a combination therapy for diabetes. The obtained in vivo experimental data on diabetes rats has shown that the designed MEMs system resulted in a higher hypoglycemic effect within add-on therapy.

Effect of γ-Aminobutyric Acid–Chitosan Nanoparticles on Glucose Homeostasis in Mice

Diabetes mellitus is the most common endocrine disease worldwide; hyperglycemia is a hallmark of this disease. To alleviate the pain caused by diabetes, developing and utilizing effective diabetic drugs to maintain or recover the function of the residual β-cells is an attractive therapeutic approach. γ-aminobutyric acid (GABA) has been shown to have such effects, but it is easy to have reduced GABA activity under physiological conditions. In the present study, GABA–chitosan nanoparticles (GABA–CS NPs) were prepared, and glucose homeostasis, pancreatic β-cell protection, and anti-inflammatory effects of GABA–CS NPs were investigated in vivo. The results showed that blood glucose levels and IL-1β levels in the GABA–CS NP-administered group were both significantly lower, whereas the PDX1 expression was significantly higher than that of the impaired group (p < 0.01). This indicates that GABA–CS NPs can efficiently maintain glucose homeostasis, protect β-cells, and inhibit inflammation. These nanoparticles have the potential to be applied for future diabetes theranostics.

Co-delivery of doxorubicin and small interfering RNA with genipin-cross-linked iron (III) oxide-polyetherimide nanoparticles for combined cancer therapy

To solve the problem of tumor multidrug resistance in cancer therapy, a new drug delivery system of genipin-cross-linked iron (III) oxide/polyetherimide nanoparticles was used to load doxorubicin and small interfering RNA for combined cancer therapy. The results showed that the drug loading and encapsulation efficiency of doxorubicin could reach 45.39% and 52.18%, respectively. Doxorubicin released from iron (III) oxide-polyetherimide-doxorubicin is about 40% in the first day and 95% in 14 days. When loading doxorubicin and small interfering RNA, small interfering RNA could be absorbed completely. Besides, small interfering RNA could strengthen the anticancer effect when iron (III) oxide-polyetherimide-doxorubicin/small interfering RNA was used for in vitro HeLa cell combined treatment, and the effect of combination group was better than that of the group with doxorubicin alone. In addition, the toxicity of iron (III) oxide-polyetherimide was low when examined by the Alamar Blue assay. Therefore, our results reveal that this new system has potential applications in the future drug combination therapy, especially in the combined targeting drug delivery field.

Preparation of ALG-g-Lys and its application as a novel drug carrier

In order to improve alginate microbead stability and further broaden the application of alginate in biomaterials, a new biomaterial, ALG-g-Lys, was prepared and its possibility as a novel drug carrier investigated. The carrier exhibited a sustained release property and preserved activity with no initial burst release, and interestingly, GP-crosslinked ALG-g-Lys microspheres showed obvious fluorescence properties, which showed promising potential for the future drug delivery systems.