Functional alginate nanoparticles for efficient intracellular release of doxorubicin and hepatoma carcinoma cell targeting therapy

Traversing the diverse avenues of exopolysaccharides-based nanocarriers in the management of cancer

Exopolysaccharides are unique polymers generated by living organisms such as algae, fungi and bacteria to protect them from environmental factors. After a fermentative process, these polymers are extracted from the medium culture. Exopolysaccharides have been explored for their anti-viral, anti-bacterial, anti-tumor, and immunomodulatory effects. Specifically, they have acquired massive attention in novel drug delivery strategies owing to their indispensable properties like biocompatibility, biodegradability, and lack of irritation. Exopolysaccharides such as dextran, alginate, hyaluronic acid, pullulan, xanthan gum, gellan gum, levan, curdlan, cellulose, chitosan, mauran, and schizophyllan exhibited excellent drug carrier properties. Specific exopolysaccharides, such as levan, chitosan, and curdlan, have demonstrated significant antitumor activity. Moreover, chitosan, hyaluronic acid and pullulan can be employed as targeting ligands decorated on nanoplatforms for effective active tumor targeting. This review shields light on the classification, unique characteristics, antitumor activities and nanocarrier properties of exopolysaccharides. In addition, in vitro human cell line experiments and preclinical studies associated with exopolysaccharide-based nanocarriers have also been highlighted.

Recent advances in pH/enzyme-responsive polysaccharide-small-molecule drug conjugates as nanotherapeutics

Now-a-days, the polysaccharides are extensively employed for the delivery of small-molecule drugs ascribed to their excellent biocompatibility, biodegradability and modifiability. An array of drug molecules is often chemically conjugated with different polysaccharides to augment their bio-performances. As compared to their therapeutic precursors, these conjugates could typically demonstrate an improved intrinsic solubility, stability, bioavailability and pharmacokinetic profiles of the drugs. In current years, various stimuli-responsive particularly pH and enzyme-sensitive linkers or pendants are also exploited to integrate the drug molecules into the polysaccharide backbone. The resulting conjugates could experience a rapid molecular conformational change upon exposure to the microenvironmental pH and enzyme changes of the diseased states, triggering the release of the bioactive cargos at the targeted sites and eventually minimize the systemic side effects. Herein, the recent advances in pH and enzyme -responsive polysaccharide-drug conjugates and their therapeutic benefits are systematically reviewed, following a brief description on the conjugation chemistry of the polysaccharides and drug molecules. The challenges and future perspectives of these conjugates are also precisely discussed.

Nano-strategies as Oral Drug Delivery Platforms for Treatment of Cancer: Challenges and Future Perspectives

Oral drug administration is the oldest and widely used method for drug administration. The objectives behind developing an oral drug delivery for the treatment of cancer are to achieve low cost treatment by utilizing novel techniques to target cancer through gut-associated lymphoid tissue (GALT) and to enhance patient comfort and compliance through a hospital-free treatment leading to "Chemotherapy at Home." Unfortunately, due to the physiological environment of the GIT and physicochemical properties of drug candidate, the efficacy of oral drug delivery methods is limited in the treatment of cancer. Due to their low hydrophilicity, high P-gp efflux and restricted intestinal permeability most of the anti-cancer drugs fail to achieve oral bioavailability. The review focuses on the efforts, challenges, opportunities and studies conducted by scientists worldwide on the oral administration of anticancer medications via nanocarriers such as liposomes, SLNs and dendrimers, because of their potential to overcome the epithelial barrier associated with GALT, as well as the applications of different polymers in targeting the cancer. The oral delivery can set newer horizons in cancer therapy to make it more patient friendly.

Glycyrrhizic Acid and Its Hydrolyzed Metabolite 18β-Glycyrrhetinic Acid as Specific Ligands for Targeting Nanosystems in the Treatment of Liver Cancer

Glycyrrhizic acid and its hydrolyzed metabolite 18β-glycyrrhetinic acid, obtained from the plant Glycyrrhiza glabra, have numerous pharmacological activities, such as anti-inflammatory, anti-ulcerative, antiallergic, immunomodulatory, antiviral, antitumor, hepatoprotective, and antioxidant effects, and others. In addition to the pharmacological activities, in the 1980s, an interaction and uptake of these molecules by the liver was verified, which was later confirmed by other studies through the discovery of specific receptors in the hepatocytes. The presence of these specific receptors in the liver led to vectorization and delivery of drugs, by the introduction of glycyrrhizic acid or glycyrrhetinic acid on the surface of nanosystems, for the treatment of liver diseases. This review describes experimental evidence of vectorization by conjugating glycyrrhizic acid or glycyrrhetinic acid to nanosystems and delivery of antitumor drugs for the treatment of liver cancer and also describes the techniques used to perform this conjugation. We have shown that due to the existence of specific receptors for these molecules, in addition to the targeting of nanosystems to hepatocytes, nanosystems having glycyrrhizic acid or glycyrrhetinic acid on their surface had the same therapeutic effect in a significantly lower dose compared to the free drug and unconjugated nanosystems, with consequent reduction of side effects and toxicity.

Recent Advances in Asialoglycoprotein Receptor and Glycyrrhetinic Acid Receptor-Mediated and/or pH-Responsive Hepatocellular Carcinoma- Targeted Drug Delivery

BACKGROUND

Hepatocellular carcinoma (HCC) seriously affects human health, especially, it easily develops multi-drug resistance (MDR) which results in treatment failure. There is an urgent need to develop highly effective and low-toxicity therapeutic agents to treat HCC and to overcome its MDR. Targeted drug delivery systems (DDS) for cancer therapy, including nanoparticles, lipids, micelles and liposomes, have been studied for decades. Recently, more attention has been paid to multifunctional DDS containing various ligands such as polymer moieties, targeting moieties, and acid-labile linkages. The polymer moieties such as poly(ethylene glycol) (PEG), chitosan (CTS), hyaluronic acid, pullulan, poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO) protect DDS from degradation. Asialoglycoprotein receptor (ASGPR) and glycyrrhetinic acid receptor (GAR) are most often used as the targeting moieties, which are overexpressed on hepatocytes. Acid-labile linkage, catering for the pH difference between tumor cells and normal tissue, has been utilized to release drugs at tumor tissue.

OBJECTIVES

This review provides a summary of the recent progress in ASGPR and GAR-mediated and/or pH-responsive HCC-targeted drug delivery.

CONCLUSION

The multifunctional DDS may prolong systemic circulation, continuously release drugs, increase the accumulation of drugs at the targeted site, enhance the anticancer effect, and reduce side effects both in vitro and in vivo. But it is rarely used to investigate MDR of HCC; therefore, it needs to be further studied before going into clinical trials.

Nanocarriers-loaded with natural actives as newer therapeutic interventions for treatment of hepatocellular carcinoma

Introduction: Cancer has always been a menace for the society. Hepatocellular carcinoma (HCC) is one of the most lethal and 3rdlargest causes of deaths around the world.Area covered: The emergence of natural actives is considered as the greatest boon for fighting cancer. The natural actives take precedence over the traditional chemotherapeutic drugs in terms of their multi-target, multi-level and coordinated effects in the treatment of HCC. Literature reports have indicated the tremendous potential of bioactive natural products in inhibiting the HCC via molecular drug targeting, augmented bioavailability, and the ability for both passive or active targeting and stimulus-responsive drug release characteristics. This review provides a newer treatment approaches involved in the mechanism of action of different natural actives used for the HCC treatment via different molecular pathways. Besides, the promising advantage of natural bioactive-loaded nanocarriers in HCC treatment has also been also presented in this review. Expert opinion: The remarkable outcomes have been observed with therapeutic efficacy of the nanocarriers of natural actives in the treatment of HCC.Furthermore, it requires a thorough assessment of the safety and efficacy evaluation of the nanocarriers for the delivery of targeted natural active ingredients in HCC.].

Al2O3 Nanoparticles Promote the Removal of Carbamazepine in Water by Chlorella vulgaris Immobilized in Sodium Alginate Gel Beads

The roles of Al2O3 nanoparticles on the removal of carbamazepine (CBZ) by Chlorella vulgaris immobilized in sodium alginate gel beads were for the first time investigated. The optimum conditions to prepare immobilized C. vulgaris beads with addition of Al2O3 nanoparticles were determined as follows: C. vulgaris density was 3.0 × 106 cells for 1 mL sodium alginate solution, Al2O3 nanoparticle concentration was 0.5 g/L, and concentrations of sodium alginate and CaCl2 were 1.6% and 1%, respectively. The results showed that the proposed algae beads achieved the highest CBZ removal rate of 89.6% after 4 days of treatment, relative to 68.84%, 48.56%, and 17.76% in sodium alginate-immobilized C. vulgaris, free microalgae, and Al2O3 nanoparticle alginate beads, respectively. The results also showed that the CBZ removal rate increased with more proposed algae beads, while decreased with increased bead diameter. The algae beads exhibited excellent CBZ removal ability even after three recycles. This work provided an economical and effective approach to remove CBZ from water.

Synthesis and anti-hepaticfibrosis of glycyrrhetinic acid derivatives with inhibiting COX-2

Many tests have shown cyclooxygenase-2 (COX-2) was closely related to the activation of hepatic stellate cells (HSCs), which further promoting the onset and development of hepatic fibrosis. According to these research findings, a series of glycyrrhetinic acid derivatives were designed and synthesized. Meanwhile, their anti-hepaticfibrotic activities were evaluated in vitro and in vivo. Firstly, in the tests of the cell models, all the compounds displayed anti-proliferative effect on the HSC-T6 activated by (transforming growth factor beta) TGF-β₁ (10 ng/mL). Among them, compounds 2 and 16 exhibited a stronger activity than the others, and their IC₅₀ values were 17.6 µM and 30.3 µM, respectively; both of them were low toxicity to normal HSC-T6 cells and WI38 cells, and they inhibited the activated HSC-T6 cells proliferation by promoting apoptosis and resting them at the G₀/G₁ phase. Secondly, compounds 2 and 16 displayed strong inhibitory effect on activation of HSCs; they not only inhibited the expression of α-SMA and Col1 in the activated HSC-T6 cells, but also decreased the levels of COX-2, TGF-β₁ and (reactive oxygen species) ROS in a concentration-dependent manner; they down-regulated the levels of three biomarkers in the process of test, but this decrease did not change linearly with the action time of compound. Thirdly, for the rats which induced with (carbontetrachloride) CCl₄, the symptoms of liver fibrosis in rats were significantly alleviated after successive administration the tested compound for 14d; the α-SMA level in liver tissue decreased in a concentration dependent manner; and the liver cell necrosis and the fat collagen fiber decreased significantly compared with the positive control group; furthermore, inflammatory infiltration was significantly lower than that of the control. This suggests the compounds possibly are candidates for hepatic fibrosis with promising application in clinic.

Nanocarrier-Based Therapeutics and Theranostics Drug Delivery Systems for Next Generation of Liver Cancer Nanodrug Modalities

The development of therapeutics and theranostic nanodrug delivery systems have posed a challenging task for the current researchers due to the requirement of having various nanocarriers and active agents for better therapy, imaging, and controlled release of drugs efficiently in one platform. The conventional liver cancer chemotherapy has many negative effects such as multiple drug resistance (MDR), high clearance rate, severe side effects, unwanted drug distribution to the specific site of liver cancer and low concentration of drug that finally reaches liver cancer cells. Therefore, it is necessary to develop novel strategies and novel nanocarriers that will carry the drug molecules specific to the affected cancerous hepatocytes in an adequate amount and duration within the therapeutic window. Therapeutics and theranostic systems have advantages over conventional chemotherapy due to the high efficacy of drug loading or drug encapsulation efficiency, high cellular uptake, high drug release, and minimum side effects. These nanocarriers possess high drug accumulation in the tumor area while minimizing toxic effects on healthy tissues. This review focuses on the current research on nanocarrier-based therapeutics and theranostic drug delivery systems excluding the negative consequences of nanotechnology in the field of drug delivery systems. However, clinical developments of theranostics nanocarriers for liver cancer are considered outside of the scope of this article. This review discusses only the recent developments of nanocarrier-based drug delivery systems for liver cancer therapy and diagnosis. The negative consequences of individual nanocarrier in the drug delivery system will also not be covered in this review.

Nanotechnology-Based Biopolymeric Oral Delivery Platforms for Advanced Cancer Treatment

Routes of drug administration and their corresponding physiochemical characteristics play major roles in drug therapeutic efficiency and biological effects. Each route of delivery has favourable aspects and limitations. The oral route of delivery is the most convenient, widely accepted and safe route. However, the oral route of chemotherapeutics to date have displayed high gastric degradation, low aqueous solubility, poor formulation stability and minimum intestinal absorption. Thus, mainstream anti-cancer drugs in current formulations are not suitable as oral chemotherapeutic formulations. The use of biopolymers such as chitosan, gelatin, hyaluronic acid and polyglutamic acid, for the synthesis of oral delivery platforms, have potential to help overcome problems associated with oral delivery of chemotherapeutics. Biopolymers have favourable stimuli-responsive properties, and thus can be used to improve oral bioavailability of anti-cancer drugs. These biopolymeric formulations can protect gastric-sensitive drugs from pH degradation, target specific binding sites for targeted absorption and consequently control drug release. In this review, the use of various biopolymers as oral drug delivery systems for chemotherapeutics will be discussed.

Natural products in licorice for the therapy of liver diseases: Progress and future opportunities

Liver diseases related complications represent a significant source of morbidity and mortality worldwide, creating a substantial economic burden. Oxidative stress, excessive inflammation, and dysregulated energy metabolism significantly contributed to liver diseases. Therefore, discovery of novel therapeutic drugs for the treatment of liver diseases are urgently required. Licorice is one of the most commonly used herbal drugs in Traditional Chinese Medicine for the treatment of liver diseases and drug-induced liver injury (DILI). Various bioactive components have been isolated and identified from the licorice, including glycyrrhizin, glycyrrhetinic acid, liquiritigenin, Isoliquiritigenin, licochalcone A, and glycycoumarin. Emerging evidence suggested that these natural products relieved liver diseases and prevented DILI through multi-targeting therapeutic mechanisms, including anti-steatosis, anti-oxidative stress, anti-inflammation, immunoregulation, anti-fibrosis, anti-cancer, and drug-drug interactions. In the current review, we summarized the recent progress in the research of hepatoprotective and toxic effects of different licorice-derived bioactive ingredients and also highlighted the potency of these compounds as promising therapeutic options for the treatment of liver diseases and DILI. We also outlined the networks of underlying molecular signaling pathways. Further pharmacology and toxicology research will contribute to the development of natural products in licorice and their derivatives as medicines with alluring prospect in the clinical application.

The effective treatment of multi-drug resistant tumors with self-assembling alginate copolymers

Alginates of two different chain lengths were alkyne functionalized on the hydroxyl group, leaving all carboxylic groups intact.

Delivery of Doxorubicin Using Double-Layered Core-Shell Nanocarrier Based on Magnetic Fe3O4 Core and Salep Shells

Herein, we developed a magnetic drug delivery system based on magnetic Fe₃O₄ nanoparticles with double shells of modified salep polysaccharide for the delivery of doxorubicin (Dox). The drug-loaded nanocarrier was synthesized in an easy way, and large amounts of drug molecules were loaded into the nanocarrier. The drug-loaded nanocarrier showed excellent pH responsibility in vitro, and large amounts of Dox were released at lower pH (60% release), whereas the nanocarrier was stable at neutral pH. The hemolysis assay results showed that the nanocarrier has negligible hemolytic effects on human red blood cells and showed good biocompatibility. Moreover, the result of coagulation assays showed that the nanocarrier was not active in any coagulation pathways. Cytotoxicity assays of nanocarrier and drug-loaded nanocarrier toward HeLa cells demonstrated that the nanocarrier has negligible toxicity, whereas the drug-loaded nanocarrier kills more than 90% of cells during 48 h. The flow cytometry analysis also showed that the uptake of drug-loaded nanocarrier into the cancerous cells is time-dependent and higher concentrations of drug internalized into the cells at longer incubation time. On the basis of the results, we suggest that the present nanocarrier can be applicable for in vivo drug delivery as an easy-made and cheap nanocarrier.

Nanoalginates via Inverse-Micelle Synthesis: Doxorubicin-Encapsulation and Breast Cancer Cytotoxicity

Crosslinked-biopolymer nanoparticles provide a convenient platform for therapeutic encapsulation and delivery. Here, we present a robust inverse-micelle process to load water-soluble drugs into a calcium-crosslinked alginate matrix. The utility of the resulting nanoalginate (NALG) carriers was assessed by a doxorubicin (DOX) formulation (NALG-DOX) and evaluating its potency on breast cancer cells (4T1). This facile synthesis process produced doxorubicin-containing particles of ~ 83 nm by hydrodynamic size and zeta potential ~ 7.2 mV. The cyclohexane/dodecylamine microemulsion yielded uniform and spherical nanoparticles as observed by electron microscopy. The uptake of the drug from the NALG-DOX formulation in 4T1 cells was observed by fluorescence microscopy employing doxorubicin's inherent fluorescence. Therapeutic efficacy of the NALG-DOX against 4T1 cells was demonstrated qualitatively through a LIVE/DEAD fluorescence assay and quantitatively via cell viability assay (Alamar Blue). In addition, IC50 values were determined, with encapsulated doxorubicin having a slightly higher value. No toxicity of the empty NALG carrier was observed. Overall, these results demonstrate the utility of this synthesis process for encapsulation of hydrophilic therapeutics and NALG to function as a drug carrier.

A conveniently synthesized Pt (IV) conjugated alginate nanoparticle with ligand self-shielded property for targeting treatment of hepatic carcinoma

The clinical translation remains a major challenge for platinum drug loaded nanoparticle due to the complexity of composition and preparation. Here we employed only three ingredients to prepare Pt (IV) prodrug-loaded ligand-induced self-assembled nanoparticles (GA-ALG@Pt NPs) via facile one-pot route for liver tumor treatment. GA-ALG@Pt NPs were found equipped with intelligently ligand self-shielded property in which the internal GA could be induced to expose by initial cellular recognition, resulting in strengthened cellular uptake (20%-30%) and prolonged blood circulation time (3.43 times). Appreciable tumor targeting ability (2 times) and especially tumor selectivity (2.5 times) were obtained. Glutathione-triggered release of therapeutic agent generated satisfactory antitumor effect. Bio-safety is also a distinguishing feature of GA-ALG@Pt NPs that greatly relief the nephrotoxicity and systematic toxicity of cisplatin. This conveniently synthesized nanoparticle processes superior targeting capacity and biosecurity, supplying an effective approach to translational cancer therapy in the future.

Bioinspired nanocarriers for an effective chemotherapy of hepatocellular carcinoma

Drug-loaded nanoparticles have been widely researched in the antitumor. However, some of them are unsatisfactory in the long blood circulation and controlled drug release. Red blood cell (RBC) membrane vesicles (RV)-coated nanoparticles have gained more and more attention in drug delivery for their many unique advantages, such as excellent stability, long blood circulation, and reduced the macrophage cells uptake. Herein, by utilizing the advantages of RV, we fabricated RV-coated poly(lactide- co-glycolide) (PLGA)-docetaxel (RV/PLGA/DTX) nanoparticles to enhance the antitumor efficiency in vivo. The RV/PLGA/DTX showed spherical morphology with particle size of about 100 nm and zeta potential at -12.63 mV, which could maintain stability for a long time. The RV/PLGA/DTX significantly enhanced cellular uptake of DTX compared to PLGA/DTX in HepG2 cells. Moreover, RV/PLGA/DTX showed the strongest antitumor effect in vitro. Prolonged blood circulation and enhanced DTX accumulation at the tumor site through enhanced permeability and retention (EPR) effect were achieved by RV/PLGA/DTX, which eventually obtained satisfactory antitumor effect and depressed system toxicity on mice bearing HepG2 xenografts mouse models when compared with free DTX. The hematoxylin and eosin (H&E) and immunofluorescence assays further proved the advantages of RV/PLGA/DTX in vivo antitumor. These RV-coated nanoparticles provide a mimetic therapy, completely inhibited the growth of the HepG2 cells, and with simple compositions, suggesting it to be an ideal strategy for improving the antitumor effect of drug-loaded nanoparticles.

Enhanced delivery of doxorubicin to the liver through self-assembled nanoparticles formed via conjugation of glycyrrhetinic acid to the hydroxyl group of hyaluronic acid

Liver-targeted nanoparticles is highly desired for better therapy of liver cancer. In this study, enhanced delivery of doxorubicin (DOX) to the liver cells through self-assembled nanoparticles formed via conjugation of glycyrrhetinic acid (GA) to the hydroxyl group of hyaluronic acid (HA) was investigated. The DOX loaded hyaluronic acid-glycyrrhetinic acid succinate (HSG) conjugates based nanoparticles (HSG/DOX nanoparticles) were sub-spherical in shape with particle size in the range of 180-280 nm, the drug loading was drug-to-carrier ratio and GA graft ratio dependent. In vitro release study suggested that the release of DOX from HSG nanoparticles was sustained and the release rate was pH and GA graft ratio dependent. MTT assay indicated the HSG/DOX nanoparticles presented a GA-dependent cytotoxicity to HepG2 cells. Pharmacokinetics study demonstrated the HSG/DOX nanoparticles could prolong blood circulation time of DOX and had a higher AUC value than that of DOX solution. Furthermore, tissue distribution study revealed the HSG/DOX nanoparticles significantly increased the accumulation of DOX in the liver and meanwhile decreased the cardiotoxicity and nephrotoxicity of DOX. Moreover, the liver targeting enhancing capacity was HSG conjugate structure dependent. The accumulation of HSG-20/DOX, HSG-12/DOX, and HSG-6/DOX nanoparticles in the liver was 4.0-, 3.1-, and 2.6-fold higher than that of DOX solution. In vivo imaging analysis further demonstrated HSG nanoparticles not only had better liver targeting effect, but also presented superior tumor targeting efficiency, and the tumor targeting capacity was also GA-dependent. These results indicated that HSG conjugates prepared via modifying the hydroxyl groups of HA have promising potential as a liver-targeting nanocarrier for the delivery of hydrophobic anti-tumor drugs.

Polysaccharide-Based Controlled Release Systems for Therapeutics Delivery and Tissue Engineering: From Bench to Bedside

Polysaccharides or polymeric carbohydrate molecules are long chains of monosaccharides that are linked by glycosidic bonds. The naturally based structural materials are widely applied in biomedical applications. This article covers four different types of polysaccharides (i.e., alginate, chitosan, hyaluronic acid, and dextran) and emphasizes their chemical modification, preparation approaches, preclinical studies, and clinical translations. Different cargo fabrication techniques are also presented in the third section. Recent progresses in preclinical applications are then discussed, including tissue engineering and treatment of diseases in both therapeutic and monitoring aspects. Finally, clinical translational studies with ongoing clinical trials are summarized and reviewed. The promise of new development in nanotechnology and polysaccharide chemistry helps clinical translation of polysaccharide-based drug delivery systems.

Fabrication of self-assembled folate-biotin-quaternized starch nanoparticles as co-carrier of doxorubicin and siRNA

In this paper, the starch was firstly modified by quaternary reagent to obtain cationic starch. Then self-assembled folate-biotin-quaternized starch nanoparticles were prepared by a one-pot synthesis via N,N'-dicyclohexylcarbodiimide/N-hydroxysuccinimide/4-dimethylaminopyridine-mediated esterification reaction. The physicochemical properties of the prepared folate-biotin-quaternized starch nanoparticles were characterized. The average diameter of folate-biotin-quaternized starch nanoparticles was 109 nm with polydispersity index of 0.183 and zeta potential of 28.59 mV. The folate-biotin-quaternized starch nanoparticles were used as co-carrier of siRNA and doxorubicin with satisfactory drug loading capacity (6.98%) and encapsulation efficiency (69.66 %), and siRNA could be efficiently encapsulated at 40/1 weight ratio of doxorubicin/folate-biotin-quaternized starch nanoparticles to siRNA. The folate-biotin-quaternized starch nanoparticles could effectively protect siRNA from degradation of serum RNAase for up to 48 h. The release characteristics of doxorubicin and siRNA from folate-biotin-quaternized starch nanoparticles were studied in different pH environment and the release behaviors of two drugs were all pH sensitive. The folate-biotin-quaternized starch nanoparticles as a potential co-carrier of anticancer agents and gene drugs was expected to achieve future practical application in vitro and in vivo.

Effects of nanoparticles in species of aquaculture interest

Recently, it was observed that there is an increasing application of nanoparticles (NPs) in aquaculture. Manufacturers are trying to use nano-based tools to remove the barriers about waterborne food, growth, reproduction, and culturing of species, their health, and water treatment in order to increase aquaculture production rates, being the safe-by-design approach still unapplied. We reviewed the applications of NPs in aquaculture evidencing that the way NPs are applied can be very different: some are direclty added to feed, other to water media or in aquaculture facilities. Traditional toxicity data cannot be easily used to infer on aquaculture mainly considering short-term exposure scenarios, underestimating the potential exposure of aquacultured species. The main outputs are (i) biological models are not recurrent, and in the case, testing protocols are frequently different; (ii) most data derived from toxicity studies are not specifically designed on aquaculture needs, thus contact time, exposure concentrations, and other ancillary conditions do not meet the required standard for aquaculture; (iii) short-term exposure periods are investigated mainly on species of indirect aquaculture interest, while shrimp and fish as final consumers in aquaculture plants are underinvestigated (scarce or unknown data on trophic chain transfer of NPs): little information is available about the amount of NPs accumulated within marketed organisms; (iv) how NPs present in the packaging of aquacultured products can affect their quality remained substantially unexplored. NPs in aquaculture are a challenging topic that must be developed in the near future to assure human health and environmental safety. Graphical abstract ᅟ.

Formation of graphene oxide-hybridized nanogels for combinative anticancer therapy

The low efficacy and high toxicity of chemotherapy have been driving increasing attention on development of combined anticancer therapy technique. In the current work, graphene oxide (GO)-hybridized nanogels (AGD) were developed for delivery of an anticancer drug (doxorubicin (DOX)), which simultaneously presented photothermal therapeutic effects against cancer cells. AGD nanogels were fabricated by in situ incorporating GO nanoplatelets into a biodegradable polymer (alginate) via a double emulsion approach using a disulfide molecule as crosslinker, followed by DOX encapsulation via electrostatic interactions. The nanogels released DOX drug in an accelerated way under both acidic and reducible conditions mimicking extracellular tumor microenvironments and intracellular compartments. The stimulative release controllability of the nanogels improved the DOX internalization and long-term drug accumulation inside A549 cells (an adenocarcinoma human alveolar basal epithelial cell line), which, together with their photothermal effect, resulted in a good anticancer cytotoxicity, indicating their promising potential for combinative anticancer therapy.

pH-Sensitive Reversible Programmed Targeting Strategy by the Self-Assembly/Disassembly of Gold Nanoparticles

A reversible programmed targeting strategy could achieve high tumor accumulation due to its long blood circulation time and high cellular internalization. Here, targeting ligand-modified poly(ethylene glycol) (PEG-ligand), dibutylamines (Bu), and pyrrolidinamines (Py) were introduced on the surface of gold nanoparticles (Au NPs) for reversible shielding/deshielding of the targeting ligands by pH-responsive self-assembly. Hydrophobic interaction and steric repulsion are the main driving forces for the self-assembly/disassembly of Au NPs. The precise self-assembly (pH ≥ 7.2) and disassembly (pH ≤ 6.8) of Au NPs with different ligands could be achieved by fine-tuning the modifying molar ratio of Bu and Py (R_m), which followed the formula R_m = 1/(-0.0013X² + 0.0323X + 1), in which X is the logarithm of the partition coefficient of the targeting ligand. The assembled/disassembled behavior of Au NPs at pH 7.2 and 6.8 was confirmed by transmission electron microscopy and dynamic light scattering. Enzyme-linked immunosorbent assays and cellular uptake studies showed that the ligands could be buried inside the assembly and exposed when disassembled. More importantly, this process was reversible, which provides the possibility of prolonging blood circulation by shielding ligands associated with the NPs that were effused from tumor tissue.

Inhibition of HeLa cell growth by doxorubicin-loaded and tuftsin-conjugated arginate-PEG microparticles

In order to improve the release pattern of chemotherapy drug and reduce the possibility of drug resistance, poly(ethylene glycol amine) (PEG)-modified alginate microparticles (ALG-PEG MPs) were developed then two different mechanisms were employed to load doxorubicin (Dox): 1) forming Dox/ALG-PEG complex by electrostatic attractions between unsaturated functional groups in Dox and ALG-PEG; 2) forming Dox-ALG-PEG complex through EDC-reaction between the amino and carboxyl groups in Dox and ALG, respectively. Additionally, tuftsin (TFT), a natural immunomodulation peptide, was conjugated to MPs in order to enhance the efficiency of cellular uptake. It was found that the Dox-ALG-PEG-TFT MPs exhibited a significantly slower release of Dox than Dox/ALG-PEG-TFT MPs in neutral medium, suggesting the role of covalent bonding in prolonging Dox retention. Besides, the release of Dox from these MPs was pH-sensitive, and the release rate was observably increased at pH 6.5 compared to the case at pH 7.4. Compared with Dox/ALG-PEG MPs and Dox-ALG-PEG MPs, their counterparts further conjugated with TFT more efficiently inhibited the growth of HeLa cells over a period of 48 h, implying the effectiveness of TFT in enhancing cellular uptake of MPs. Over a period of 48 h, Dox-ALG-PEG-TFT MPs inhibited the growth of HeLa cells less efficiently than Dox/ALG-PEG-TFT MPs but the difference was not significant (p > 0.05). In consideration of the prolonged and sustained release of Dox, Dox-ALG-PEG-TFT MPs possess the advantages for long-term treatment.

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Dox-ALG-PEG-TFT exhibited slower release of Dox than Dox/ALG-PEG-TFT.

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Release of Dox from Dox-ALG-PEG-TFT and Dox/ALG-PEG-TFT was pH-sensitive.

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Further conjugation with TFT enhanced the efficiency of Dox/ALG-PEG and Dox-ALG-PEG in inhibiting HeLa cell growth.

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Dox-ALG-PEG-TFT MPs possess the advantages for long-term treatment over Dox/ALG-PEG-TFT MPs.

Targeted antigen delivery to dendritic cell via functionalized alginate nanoparticles for cancer immunotherapy

The purpose of the present study was to identify an "easy-to-adopt" strategy to enhance immune responses using functionalized alginate (ALG) nanoparticles (MAN-ALG/ALG=OVA NPs), which were prepared by CaCl₂ cross-linking of two different types of ALG. The mannose (MAN) modified ALG (MAN-ALG) was used for dendritic cell targeting. The other component, composed of ovalbumin (OVA), a model antigen, is conjugated to ALG (ALG=OVA) via pH sensitive Schiff base bond. Grafting of alginate was demonstrated by FT-IR and ¹H NMR, while the morphological structure, particle size, Zeta potential of MAN-ALG/ALG=OVA NPs were measured using TEM and DLS. The OVA releasing behavior of MAN-ALG/ALG=OVA NPs was determined as a function of pH. Antigen uptake was examined by flow cytometry and confocal laser scanning microscopy in vitro using mouse bone marrow dendritic cells (BMDCs). The results showed that MAN-ALG/ALG=OVA NPs facilitated antigen uptake of BMDCs and cytosolic release of the antigen. Significant up-regulation of cytokine secretion and expression levels of the surface co-stimulatory molecules were also observed in MAN-ALG/ALG=OVA NPs-treated BMDCs, compared to free OVA. In vivo bio-distribution study using Cy7 (a near-infrared fluorescence dye) labeled MAN-ALG/ALG=OVA NPs showed efficient in vivo trafficking of the nanoparticles from the injection site to the draining lymph nodes. Moreover, MAN-ALG/ALG=OVA NPs were found to enhance cross-presentation of OVA to B3Z T cell hybridoma in vitro. Subcutaneous administration of MAN-ALG/ALG=OVA NPs also induced major cytotoxic T lymphocytes (CTL) response and inhibition of E.G7 tumor growth in C57BL/6 mice. In summary, we report here that the MAN-ALG/ALG=OVA NPs have the potential as a potent nanovaccine for cancer immunotherapy.

Hydrogel-Based Materials for Delivery of Herbal Medicines

Herbal medicine, as an integral component of oriental medicine, has assimilated into the lives of Asian people for millennia. The therapeutic efficiency of herbal extracts and ingredients has, however, been limited by various factors, including the lack of targeting capacity and poor bioavailability. Hydrogels are hydrophilic polymer networks that can imbibe a substantial amount of fluids. They are biocompatible, and may enable sustained drug release. Hydrogels, therefore, have attracted widespread studies in pharmaceutical formulation. This article first reviews the latest progress in the development of hydrogel-based materials as carriers of herbal medicines, followed by a discussion of the relationships between hydrogel properties and carrier performance. Finally, the promising potential of using hydrogels to combine medicinal herbs with synthetic drugs in one single treatment will be highlighted as an avenue for future research.

Redox- and light-responsive alginate nanoparticles as effective drug carriers for combinational anticancer therapy

Nanoparticles have been extensively explored as effective means to deliver chemotherapeutic agents or photosensitizers for chemotherapy or photodynamic therapy (PDT) against cancer. In the present work, pheophorbide A (PheoA), a hydrophobic photosensitizer, was conjugated via a redox-sensitive disulfide linkage to alginate (PheoA-ALG). Anticancer agent, doxorubicin (DOX), was also loaded within the PheoA-ALG nanoparticles (DOX/PheoA-ALG NPs) and used as drug carriers for combinational antitumor treatment. The DOX/PheoA-ALG NPs were spherical in shape with a uniform diameter of approximately 210 nm. Redox-responsive drug releasing properties were shown by the DOX/PheoA-ALG NPs, with an accelerated amount of DOX and PheoA release observed in the presence of a high glutathione level (10 mM). Cellular uptake results showed that DOX/PheoA-ALG NPs were readily taken up by B16 tumor cells (murine melanoma) and enhanced DOX and PheoA uptake were detectable in the DOX/PheoA-ALG NPs-treated B16 cells in comparison to carrier free drugs. DOX/PheoA-ALG NPs also elicited intracellular ROS generation, which leads to enhanced toxicity in B16 cells. In vivo studies using B16 tumor-bearing mice further demonstrated that DOX/PheoA-ALG NPs were preferentially accumulated in tumor tissues, resulting in substantial inhibition of B16 tumor growth by chemotherapy and photodynamic therapy, which is also attributable to DOX/PheoA-ALG NP-elicited increase of serum INF-λ levels. Our results demonstrate a major potential of DOX/PheoA-ALG NPs for combinational cancer therapy.

Co-delivery of cisplatin and paclitaxel by folic acid conjugated amphiphilic PEG-PLGA copolymer nanoparticles for the treatment of non-small lung cancer

An amphiphilic copolymer, folic acid (FA) modified poly(ethylene glycol)-poly(lactic-co-glycolic acid) (FA-PEG-PLGA) was prepared and explored as a nanometer carrier for the co-delivery of cisplatin (cis-diaminodichloroplatinum, CDDP) and paclitaxel (PTX). CDDP and PTX were encapsulated inside the hydrophobic inner core and chelated to the middle shell, respectively. PEG provided the outer corona for prolonged circulation. An in vitro release profile of the CDDP + PTX-encapsulated nanoparticles revealed that the PTX chelation cross-link prevented an initial burst release of CDDP. After an incubation period of 24 hours, the CDDP+PTX-encapsulated nanoparticles exhibited a highly synergistic effect for the inhibition of A549 (FA receptor negative) and M109 (FA receptor positive) lung cancer cell line proliferation. Pharmacokinetic experiment and distribution research shows that nanoparticles have longer circulation time in the blood and can prolong the treatment times of chemotherapeutic drugs. For the in vivo treatment of A549 cells xeno-graft lung tumor, the CDDP+PTX-encapsulated nanoparticles displayed an obvious tumor inhibiting effect with an 89.96% tumor suppression rate (TSR). This TSR was significantly higher than that of free chemotherapy drug combination or nanoparticles with a single drug. For M109 cells xeno-graft tumor, the TSR was 95.03%. In vitro and in vivo experiments have all shown that the CDDP+PTX-encapsulated nanoparticles have better targeting and antitumor effects in M109 cells than CDDP+PTX-loaded PEG-PLGA nanoparticles (p < 0.05). In addition, more importantly, the enhanced anti-tumor efficacy of the CDDP+PTX-encapsulated nanoparticles came with reduced side-effects. No obvious body weight loss or functional changes occurred within blood components, liver, or kidneys during the treatment of A549 and M109 tumor-bearing mice with the CDDP+PTX-encapsulated nanoparticles. Thus, the FA modified amphiphilic copolymer-based combination of CDDP and PTX may provide useful guidance for effective and safe cancer chemotherapy, especially in tumors with high FA receptor expression.

Carbohydrate-based amphiphilic nano delivery systems for cancer therapy

Nanoparticles (NPs) are novel drug delivery systems that have been attracting more and more attention in recent years, and have been used for the treatment of cancer, infection, inflammation and other diseases. Among the numerous classes of materials employed for constructing NPs, organic polymers are outstanding due to the flexibility of design and synthesis and the ease of modification and functionalization. In particular, NP based amphiphilic polymers make a great contribution to the delivery of poorly-water soluble drugs. For example, natural, biocompatible and biodegradable products like polysaccharides are widely used as building blocks for the preparation of such drug delivery vehicles. This review will detail carbohydrate based amphiphilic polymeric systems for cancer therapy. Specifically, it focuses on the nature of the polymer employed for the preparation of targeted nanocarriers, the synthetic methods, as well as strategies for the application and evaluation of biological activity. Applications of the amphiphilic polymer systems include drug delivery, gene delivery, photosensitizer delivery, diagnostic imaging and specific ligand-assisted cellular uptake. As a result, a thorough understanding of the relationship between chemical structure and biological properties facilitate the optimal design and rational clinical application of the resulting carbohydrate based nano delivery systems for cancer therapy.

Seaweed Polysaccharide-Based Nanoparticles: Preparation and Applications for Drug Delivery

In recent years, there have been major advances and increasing amounts of research on the utilization of natural polymeric materials as drug delivery vehicles due to their biocompatibility and biodegradability. Seaweed polysaccharides are abundant resources and have been extensively studied for several biological, biomedical, and functional food applications. The exploration of seaweed polysaccharides for drug delivery applications is still in its infancy. Alginate, carrageenan, fucoidan, ulvan, and laminarin are polysaccharides commonly isolated from seaweed. These natural polymers can be converted into nanoparticles (NPs) by different types of methods, such as ionic gelation, emulsion, and polyelectrolyte complexing. Ionic gelation and polyelectrolyte complexing are commonly employed by adding cationic molecules to these anionic polymers to produce NPs of a desired shape, size, and charge. In the present review, we have discussed the preparation of seaweed polysaccharide-based NPs using different types of methods as well as their usage as carriers for the delivery of various therapeutic molecules (e.g., proteins, peptides, anti-cancer drugs, and antibiotics). Seaweed polysaccharide-based NPs exhibit suitable particle size, high drug encapsulation, and sustained drug release with high biocompatibility, thereby demonstrating their high potential for safe and efficient drug delivery.

Glycyrrhetinic Acid Mediated Drug Delivery Carriers for Hepatocellular Carcinoma Therapy

Glycyrrhetinic acid (GA), the main hydrolysate of glycyrrhizic acid extracted from the root of licorice, has been used in hepatocellular carcinoma (HCC) therapy. Particularly, GA as a ligand in HCC therapy has been widely explored in different drug delivery systems, including liposomes, micelles, and nanoparticles. There is considerable interest worldwide with respect to the development of GA-modified drug delivery systems due to the extensive presence of GA receptors on the surface of hepatocyte. Up until now, much work has been focused on developing GA-modified drug delivery systems which bear good liver- or hepatocyte-targeted efficiency both in vitro and in vivo. Owing to its contribution in overcoming the limitations of low lipophilicity and poor bioavailability as well as its ability to promote receptor-mediated endocytosis, GA-modified drug delivery systems play an important role in enhancing liver-targeting efficacy and thus are focused on the treatment of HCC. Moreover, since GA-modified delivery systems present more favorable pharmacokinetic properties and hepatocyte-targeting effects, they may be a promising formulation for GA in the treatment of HCC. In this review, we will give an overview of GA-modified novel drug delivery systems, paying attention to their efficacy in treating HCC and discussing their mechanism and the treatment effects.

Nanoparticle-liver interactions: Cellular uptake and hepatobiliary elimination

30-99% of administered nanoparticles will accumulate and sequester in the liver after administration into the body. This results in reduced delivery to the targeted diseased tissue and potentially leads to increased toxicity at the hepatic cellular level. This review article focuses on the inter- and intra-cellular interaction between nanoparticles and hepatic cells, the elimination mechanism of nanoparticles through the hepatobiliary system, and current strategies to manipulate liver sequestration. The ability to solve the "nanoparticle-liver" interaction is critical to the clinical translation of nanotechnology for diagnosing and treating cancer, diabetes, cardiovascular disorders, and other diseases.

Multicompartment Microgel Beads for Co-Delivery of Multiple Drugs at Individual Release Rates

Multidrug therapy may yield higher therapeutic effects as compared to monotherapy, yet its wide application has been hampered by the limitations of conventional drug delivery systems, in which not only incompatible drugs cannot be co-delivered but also the release rates of individual co-delivered drugs cannot be tuned separately. Regarding these limitations, we adopt the microfluidic electrospray technology to fabricate alginate-based multicompartment microgel beads. By using cadmium-telluride (CdTe) quantum dots (QDs) and a quenching agent as a model pair, the beads are shown to effectively separate incompatible drugs during co-delivery, and significantly prolong the time of observable fluorescence emission from QDs co-delivered with a quenching agent. Moreover, the drug release rates from different compartments can be tuned using the polymer blending technique to achieve a variety of drug release patterns. This study is one of the first to adopt the microfluidic electrospray technology to generate microgel beads with such versatility for co-delivery of multiple drugs. Our results provide evidence for the promising potential of our beads to be further developed as a carrier for multidrug therapy and other applications that require co-administration of multiple bioactive agents.