Fucoxanthin Loaded in Palm Stearin- and Cholesterol-Based Solid Lipid Nanoparticle-Microcapsules, with Improved Stability and Bioavailability In Vivo.

Fucoxanthin (FX) is a marine carotenoid that has proven to be a promising marine drug due to the multiple bioactivities it possesses. However, the instability and poor bioavailability of FX greatly limit its application in pharmaceuticals or functional foods. In this study, the creative construction of a solid lipid nanoparticle-microcapsule delivery system using mixed lipids of palm stearin and cholesterol wrapped with gelatin/Arabic gum to load lipophilic FX was fabricated, aiming to improve the stability and bioavailability of FX. The results showed that the encapsulated efficiency (EE) and drug loading capacity (LC) of optimized FX microcapsules (FX-MCs) obtained were as high as 96.24 ± 4.60% and 0.85 ± 0.04%, respectively, after single-factor experiments. The average particle size was 1154 ± 54 nm with negative Zeta potential (-20.71 ± 0.93 mV) as depicted with size-zeta potential spectrometer. The differential scanning calorimeter (DSC) and thermogravimetric analyzer (TG) results indicated that FX-MC has a higher Tg and slower weight loss than FX monomers (FX crystal) and blank MCs. Besides, The Fourier transform infrared spectrometer (FTIR) confirmed the good double encapsulation of FX into the solid lipid and composite coacervate. Moreover, the encapsulated FX showed higher storage stability, sustained release (55.02 ± 2.80% release in 8 h), and significantly improved bioavailability (712.33%) when compared to free FX. The research results can provide a principle theoretical basis for the development and application of FX in pharmaceuticals or functional foods.

Metal Phenolic Network-Integrated Multistage Nanosystem for Enhanced Drug Delivery to Solid Tumors.

Metal-phenolic networks (MPNs) are an emerging class of supramolecular surface modifiers with potential use in various fields including drug delivery. Here, the development of a unique MPN-integrated core-satellite nanosystem (CS-NS) is reported. The "core" component of CS-NS comprises a liposome loaded with EDTA (a metal ion chelator) in the aqueous core and DiR (a near-infrared photothermal transducer) in the bilayer. The "satellite" component comprises mesoporous silica nanoparticles (MSNs) encapsulating doxorubicin and is coated with a Cu2+ -tannic acid MPN. Liposomes and MSNs self-assemble into the CS-NS through adhesion mediated by the MPN. When irradiated with an 808 nm laser, CS-NS liberated the entrapped EDTA, leading to Cu2+ chelation and subsequent disassembly of the core-satellite nanostructure. Photo-conversion from the large assembly to the small constituent particles proceeded within 5 min. Light-triggered CS-NS disassembly enhanced the carrier and cargo penetration and accumulation in tumor spheroids in vitro and in orthotopic murine mammary tumors in vivo. CS-NS is long circulating in the blood and conferred improved survival outcomes to tumor-bearing mice treated with light, compared to controls. These results demonstrate an MPN-integrated multistage nanosystem for improved solid tumor treatment.

Nanobowl-Supported Liposomes Improve Drug Loading and Delivery.

Liposomal drug delivery for cancer therapy can be limited due to drug leakage in circulation. Here, we develop a new method to enhance the stability of actively loaded liposomal doxorubicin (DOX) through embedding a stiff nanobowl in the liposomal water cavity. Nanobowl-supported liposomal DOX (DOX@NbLipo) resists the influence of plasma protein and blood flow shear force to prevent drug leakage. This approach yields improved drug delivery to tumor sites and enhanced antitumor efficacy. Compared to alternative methods of modifying liposome surface and composition for stability, this approach designs a physical support for an all-aqueous nanoliposomal cavity. Nanobowl stabilization of liposomes is a simple and effective method to improve carrier stability and drug delivery.

[Histological and histochemical studies on mouthpart of Whitmania pigra at different months age].

Mouthpart developmental histology of Whitmania pigra at different month of age were studied by paraffin section, HE staining combined alcian blue and periodic acid schifts reaction procedure (AB-PAS). The following results was obtained: Change ranges: oral width 0.6 mm (1-3 month), 1.2 mm (34 month); oral diameter 0.3 mm (1-3 month); 1.2 mm (34 month), the oral size reached maximum during 4-6 months and unchanged thereafter. Oral lip had a thin protective film located in the front of the mouthpart. The W. pigra possessed three jaws in oral cavity, the big one was in dorsum, the other two separated on both side of abdomen respectively. Jaws and muscular pharynx were interrelated closely. The jaws were composed by cuticle, epithelial layer, muscularis and jaw cavity from outside to inside. In the front of jaws had mastoid abdomen with function of secreting acidophilic granule from 2 month age. Oral cavity was composed by mucosa, submucosa and muscularis inside and outside. Oral cavity was rich of peristomial nerves. And pharynx was composed of mucosa, muscularis, adventitia from inside to outside. The folds height and width become heighten and thicken. Mucosa epithelium from complex flat epithelium changed into columnar epithelium, muscularis gradually developed into thickened along with growing. Muscular thickness reached maximum at 4 months. Mucous cells of W. pigra were classified into I-IV types based on different staining and two mainly morphological shapes (Tubular, Pear-shaped). Jaws, oral cavity, pharynx by AB-PAS staining showed little changes at different month of age. Mucous cells were few at 1 month age, and type II cells were increased rapidly in 2-3 month age in oral lip. Oral cavity contains more mucous gland cells type I. Under the muscularis there were connective tissues which distributed a few of mucous cells type II.

Biomimetic Liposomal Nanoplatinum for Targeted Cancer Chemophototherapy.

Photodynamic therapy (PDT) of cancer is limited by tumor hypoxia. Platinum nanoparticles (nano-Pt) as a catalase-like nanoenzyme can enhance PDT through catalytic oxygen supply. However, the cytotoxic activity of nano-Pt is not comprehensively considered in the existing methods to exert their multifunctional antitumor effects. Here, nano-Pt are loaded into liposomes via reverse phase evaporation. The clinical photosensitizer verteporfin (VP) is loaded in the lipid bilayer to confer PDT activity. Murine macrophage cell membranes are hybridized into the liposomal membrane to confer biomimetic and targeting features. The resulting liposomal system, termed "nano-Pt/VP@MLipo," is investigated for chemophototherapy in vitro and in vivo in mouse tumor models. At the tumor site, oxygen produced by nano-Pt catalyzation improves the VP-mediated PDT, which in turn triggers the release of nano-Pt via membrane permeabilization. The ultrasmall 3-5 nm nano-Pt enables better penetration in tumors, which is also facilitated by the generated oxygen gas, for enhanced chemotherapy. Chemophototherapy with a single injection of nano-Pt/VP@MLipo and light irradiation inhibits the growth of aggressive 4T1 tumors and their lung metastasis, and prolongs animal survival without overt toxicity.

Biomimetic drug-delivery systems for the management of brain diseases.

Acting as a double-edged sword, the blood-brain barrier (BBB) is essential for maintaining brain homeostasis by restricting the entry of small molecules and most macromolecules from blood. However, it also largely limits the brain delivery of most drugs. Even if a drug can penetrate the BBB, its accumulation in the intracerebral pathological regions is relatively low. Thus, an optimal drug-delivery system (DDS) for the management of brain diseases needs to display BBB permeability, lesion-targeting capability, and acceptable safety. Biomimetic DDSs, developed by directly utilizing or mimicking the biological structures and processes, provide promising approaches for overcoming the barriers to brain drug delivery. The present review summarizes the biological properties and biomedical applications of the biomimetic DDSs including the cell membrane-based DDS, lipoprotein-based DDS, exosome-based DDS, virus-based DDS, protein template-based DDS and peptide template-based DDS for the management of brain diseases.

A rapid and scalable integrated membrane separation process for purification of polysaccharides from Enteromorpha prolifera.

An integrated membrane separation process combining the tubular ceramic microfiltration (MF) membrane and the flat-sheet ultrafiltration (UF) membrane was developed to purify polysaccharides from Enteromorpha prolifera. The effects of membrane pore size, molecular weight cut-off (MWCO), transmembrane pressure (TMP) and adding-water multiples on membrane performance were in-depth studied. The results indicated that the optimal membrane pore size and TMP of the tubular ceramic MF process were found to be 1.2 µm and 0.225 MPa, and the optimal MWCO and TMP of the flat-sheet UF process were found to be 100 kDa and 0.3 MPa. The yields of polysaccharides were increased and optimized while the adding-water multiples was 1 during the diafiltration procedure. Furthermore, the water fluxes could be completely recovered using the specialized membrane cleaning methods, which ensured the reuse of membrane elements and satisfied the demands of industrial production. After purification by this integrated membrane separation process, the content of polysaccharides reached to 96.3%. The purified polysaccharides exhibited the superior moisture absorption and moisture retention properties compared to glycerol, polyethylene glycol (PEG) and luffa water.

In vivo tumor targeting of tumor necrosis factor-alpha-loaded stealth nanoparticles: effect of MePEG molecular weight and particle size.

The aim of this study is to reveal the influence of methoxypolyethyleneglycol (MePEG) molecular weight and particle size of stealth nanoparticles on their in vivo tumor targeting properties. Three sizes (80, 170 and 240nm) of poly methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate (PEG-PHDCA) nanoparticles loading recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) were prepared at different MePEG molecular weights (MW=2000, 5000 and 10,000) using double emulsion method. The opsonization in mouse serum was evaluated by Coomassie brilliant blue staining of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Phagocytosis was evaluated by incubating (125)I-rHuTNF-alpha-loaded nanoparticles with mouse macrophages (RAW264.7). The pharmacokinetics, biodistribution and tumor targeting studies were performed in S-180 tumor-bearing mice. Higher MePEG molecular weight provided thicker fixed aqueous layer thickness (FALT) and smaller particle size offered higher surface MePEG density. The serum protein adsorption and phagocytic uptake were markedly decreased for the nanoparticles with higher MePEG molecular weight or smaller size. The particles (80nm) made of PEG(5000)-PHDCA, possessing a thicker FALT (5.16nm) and a shortest distance (0.87nm) between two neighboring MePEG chains, showed the strongest capacity of decreasing protein adsorption and phagocytic uptake. These particles extended the half-life of rHuTNF-alpha in S-180 tumor-bearing mice by 24-fold (from 28.2 min to 11.33 h), elevated the rHuTNF-alpha peak concentration in S-180 tumors by 2.85-fold and increased the area under the intratumoral rHuTNF-alpha concentration curve by 7.44-fold. The results of the present study showed PEG-PHDCA nanoparticles with higher MePEG molecular weight and smaller particle size could achieve higher in vivo tumor targeting efficiency.

[Influence of particle size and MePEG molecular weight on in vitro macrophage uptake and in vivo long circulating of stealth nanoparticles in rats].

AIM: To investigate the influence of particle size and methoxypolyethyleneglycol (MePEG) molecular weight on the in vitro macrophage uptake and in vivo long circulating of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha)-loaded stealth nanoparticles in rats. METHODS: Three sizes (approximately 80, 70 and 240 nm) of poly (methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEG-PHDCA) nanoparticles loading rHuTNF-alpha were prepared at different MePEG molecular weights (Mr 2,000, 5,000, 10,000) using the double emulsion method. The in vitro macrophage uptake and in vivo long circulating properties in rats were examined and compared. RESULTS: The uptake by macrophages decreased and the half-life of rHuTNF-alpha in rat increased with the increase of MePEG molecular weight or the decrease of particle size. The linear-ships between particle size and MePEG molecular weight and the in vitro macrophage uptake and in vivo long circulating properties were fairly good. Having the highest MePEG surface density (1.32 nm(-2)) , the shortest average distance between neighboring MePEG chain (0.87 nm) and the thicker fixed aqueous layer thickness (FALT, 5.16 nm), PEG5,000-PHDCA nanoparticles (80.0 nm) earned the strongest potency of decreasing uptake by macrophages and prolonging the half-life of rHuTNF-alpha in rat. CONCLUSION: Within the experimental limits, particle size and MePEG molecular weight had dramatic influence on in vitro macrophage uptake and in vivo long circulating properties of rHuTNF-alpha-loaded stealth nanoparticles.

Tumor priming using metronomic chemotherapy with neovasculature-targeted, nanoparticulate paclitaxel.

Normalization of the tumor microenvironment is a promising approach to render conventional chemotherapy more effective. Although passively targeted drug nanocarriers have been investigated to this end, actively targeted tumor priming remains to be explored. In this work, we demonstrate an effective tumor priming strategy using metronomic application of nanoparticles actively targeted to tumor neovasculature. F56 peptide-conjugated paclitaxel-loaded nanoparticles (F56-PTX-NP) were formulated from PEGylated polylactide using an oil in water emulsion approach. Metronomic F56-PTX-NP specifically targeted tumor vascular endothelial cells (ECs), pruned vessels with strong antiangiogenic activity and induced thrombospondin-1 (TSP-1) secretion from ECs. The treatment induced tumor vasculature normalization as evidenced by significantly increased coverage of basement membrane and pericytes. The tumor microenvironment was altered with enhanced pO2, lower interstitial fluid pressure, and enhanced vascular perfusion and doxorubicin delivery. A "normalization window" of at least 9 days was induced, which was longer than other approaches using antiangiogenic agents. Together, these results show that metronomic, actively-targeted nanomedicine can induce tumor vascular normalization and modulate the tumor microenvironment, opening a window of opportunity for effective combination chemotherapies.

A Rapid LC-HRMS Method for the Determination of Domoic Acid in Urine Using a Self-Assembly Pipette Tip Solid-Phase Extraction.

In this study, we developed a self-assembly pipette tip solid-phase extraction (PTSPE) method using a high molecular weight polymer material (PAX) as the adsorbent for the determination of domoic acid (DA) in human urine samples by liquid chromatography high-resolution mass spectrometry (LC-HRMS) analysis. The PTSPE cartridge, assembled by packing 9.1 mg of PAX as sorbent into a 200 µL pipette tip, showed high adsorption capacity for DA owing to the strong cationic properties of PAX. Compared with conventional SPE, the PTSPE is simple and fast, and shows some advantages in the aspects of less solvent consumption, low cost, the absence of the evaporation step, and short time requirement. All the parameters influencing the extraction efficiency such as pH, the amount of sorbent, the number of aspirating/dispensing cycles, and the type and volume of eluent in PTSPE were carefully investigated and optimized. Under the optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) values of DA were 0.12 µg/L and 0.37 µg/L respectively. The extraction recoveries of DA from the urine samples spiked at four different concentrations were in a range from 88.4% to 102.5%. The intra- and inter-day precisions varied from 2.1% to 7.6% and from 2.6% to 12.7%, respectively. The accuracy ranged from -1.9% to -7.4%.

Peptide-conjugated biodegradable nanoparticles as a carrier to target paclitaxel to tumor neovasculature.

Antiangiogenic cancer therapy can be achieved through the targeted delivery of antiangiogenic agents to the endothelial cells of tumor neovasculature. In the present study, we developed a drug delivery system (DDS), nanoparticles conjugated with K237-(HTMYYHHYQHHL) peptides for tumor neovasculature targeting drug delivery. Paclitaxel, a chemotherapeutic agent with potent antiangiogenic activity, was used as a prototype drug. We synthesized the aldehyde poly(ethylene glycol)-poly(lactide) (aldehyde-PEG-PLA) block copolymer by ring opening polymerization. The nanoparticles loading paclitaxel (PTX-NP) were fabricated using the O/W emulsion and evaporation technique. K237 ligand, a peptide that can bind to the KDR receptors predominantly expressed on the surface of tumor neovasculature endothelial cells with high affinity and specificity and inhibit the VEGF-KDR angiogenic signal pathway, was conjugated to the aldehyde group of PEG chain using the N-terminal PEGylation technique. The K237 conjugated paclitaxel-loaded nanoparticles (K237-PTX-NP) had a hydrodynamic diameter of 150 nm. The K237 density on nanoparticle surface was 474 and the mean distance between two neighboring PEG chains linked to K237 peptide was 12 nm. The K237 conjugated nanoparticles could be significantly internalized by human umbilical vein endothelial cells (HUVEC) through the K237-KDR interaction, and this facilitated uptake led to the expected enhanced antiangiogenic activity shown by HUVEC proliferation, migration and tube formation compared to cells treated with the commercial formulation Taxol and PTX-NP. The long-circulating property and the K237 ligand of K237-PTX-NP warranted rapid, long-term, and accurate in vivo tumor neovasculature targeting, and thereafter the significant apoptosis of tumor neovasculature endothelial cells and necrosis of tumor tissues of MDA-MB-231 breast tumors implanted in female BLAB/c nude mice. This nanoparticulate DDS offers a new strategy for paclitaxel chemotherapy application and it could also be used to carry other chemotherapeutic drugs, genes, and proteins with antiangiogenic activity for antiangiogenic cancer therapy.