In vitro evaluation on novel modified chitosan for targeted antitumor drug delivery

Recent findings in molecular reactions of E. coli as exposed to alkylated, nano- and ordinary chitosans

The antibacterial effects of chitosan have been widely studied, but the underlying molecular mechanisms are not fully understood. We investigated the molecular responses of Escherichia coli MG1655 cell, a model gram-negative bacterium, upon exposure to chitosan (Cs), alkylated Cs (AlkCs), and chitosan nanoparticles (CsNPs). Nine target genes involved in relevant signaling pathways (ompF, ompC, ompA, mrcA, mrcB, mgtA, glnA, kdpA, lptA) were selected for analysis. A significant reduction in the expression of mrcA, mgtA, glnA, and lptA genes was observed in the cells treated with Cs. Those treated with Cs, AlkCs, and CsNPs revealed an increase in ompF gene expression, but the expression level was lower in the cells treated with AlkCs and CsNPs compared to Cs. This increase in porin expression suggests compromised membrane integrity and disrupted nutrient transport. In addition, the changes in the expression of mgtA, kdpA, and glnA are related to different effects on membrane permeability. The higher expression in the genes mrcA and mrcB is associated with morphological changes of cells treated with AlkCs and CsNPs. These findings contribute to our understanding of the molecular mechanisms underlying chitosan-induced stress responses and provide insights for the development of safer antimicrobial compounds in the future.

Polyporus umbellatus polysaccharide iron-based nanocomposite for synergistic M1 polarization of TAMs and combinational anti-breast cancer therapy

M1 polarization of tumor-associated macrophages (TAMs) is a promising approach to breaking through therapeutic barriers imposed by the immunosuppressive tumor microenvironment (TME). As a clinically-used immunopotentiator for cancer patients after chemotherapies; however, the immunomodulatory mechanism and potential of polyporus polysaccharide (PPS) remains unclear. Here, we present mannose-decorated PPS-loaded superparamagnetic iron-based nanocomposites (Man/PPS-SPIONs) for synergistic M1 polarization of TAMs and consequent combinational anti-breast cancer therapy. Once internalized by M2-like TAMs, PPS released from Man/PPS-SPIONs induces the M1 polarization via IFN-γ secretion and downstream NF-κB pathway activating. The SPIONs within the nanocomposites mediate a Fenton reaction, producing OH· and activating the subsequent NF-κB/MAPK pathway, further facilitating the M1 polarization. The Man/PPS-SPIONs thereby establish a positive feedback loop of M1 polarization driven by the "IFN-γ-Fenton-NF-κB/MAPK" multi-pathway, leading to a series of anti-tumoral immunologic responses in the TME and holding promising potential in combinational anticancer therapies. Our study offers a new strategy to amplify TME engineering by combinational natural carbohydrate polymers and iron-based materials.

Simultaneous chemotherapy/sonodynamic therapy of the melanoma cancer cells using a gold-paclitaxel nanostructure

Nanodrug delivery systems are novel strategies for tumor treatment since delivery of chemotherapy drugs such as paclitaxel (PTX) is associated with substantial challenges due to its poor aqueous solubility. In addition, sonodynamic therapy (SDT) is a promising approach that can increase the uptake, accumulation, and dispersion of desirable amounts of the drugs by activating sonosensitizer and enhancing cell membrane permeability. Herein, gold-paclitaxel nanoparticles (Au-PTX NPs) were synthesized and characterized to evaluate the cytotoxicity toward C540 cancer cells in comparison of free PTX, AuNPs, and AuNPs+free PTX in the absence and presence of ultrasound radiation. Evidence shows that AuNPs have a median diameter size of 95.0 ± 15.4, while the size of Au-PTX NPs is roughly 219.7 ±  40.4 nm. Negative zeta-potential results indicate high stability and good dispersion of nanoparticles. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay results revealed that Au-PTX NPs increased the cytotoxicity compared to other treatment groups that ensure the great potential of AuNPs as a promising nano-carrier for PTX drug delivery. Moreover, the viability of C540 cells treated by Au-PTX NPs under ultrasound radiation was decreased significantly by generating more reactive oxygen species (ROS) upon STD, with representing synergism effects confirming the role of gold nanoparticles as an excellent sonosensitizer and the role of SDT as an adjunctive treatment method with chemotherapy.

Discussions on the Properties of Emulsion Prepared by Using an Amphoteric Chitosan as an Emulsifier

A typical emulsion contains oil and water phases, and these two phases can be combined by an emulsifier with both lipophilic and hydrophilic groups to form a mixture. If the component of water is more than oil, the mixture is termed as o/w emulsion. The water is called the continuous phase and the oil is called the dispersed phase. Oppositely, if the component of oil is more than water, the mixture is termed as w/o emulsion. The oil is called the continuous phase and the water is called the dispersed phase. Chitosan, which is biocompatible and non-toxic, was modified as an amphoteric emulsifier to replace sodium acrylates copolymer in the preparation of emulsions. Both sodium acrylates copolymer and the modified chitosan were used as emulsifiers, respectively, and the properties of moisturizing, transmittance, the number of bacteria, and emulsion stability were measured. The experimental results showed that the amount of amphoteric chitosan is less than that of sodium acrylate copolymer by 20% under a similar degree of emulsification. The measurement of spatial moisture showed the difference in equilibrium humidity was in the range of 2.05 to 2.20 gH2O/kg dry air, indicating that the moisture retention of the modified chitosan is better. In addition, the calculation of bacterial growth confirmed that the number of bacteria in the amphoteric chitosan emulsion and the sodium acrylate copolymer emulsion were 80 and 560, respectively. The emulsion stability was tested by the separation of oil and water phases in the diluted emulsion and by centrifugal accelerated sedimentation. The results showed that, for both emulsifiers, no separation of the oil and water phases occurred within one hour, and the stability of the modified chitosan emulsion was better. Therefore, the modified chitosan successfully substitutes sodium acrylates copolymer as an emulsifier in the preparation of emulsion.

Chitosan: A versatile bio-platform for breast cancer theranostics

Breast cancer is considered one of the utmost neoplastic diseases globally, with a high death rate of patients. Over the last decades, many approaches have been studied to early diagnose and treat it, such as chemotherapy, hormone therapy, immunotherapy, and MRI and biomarker tests; do not show the optimal efficacy. These existing approaches are accompanied by severe side effects, thus recognizing these challenges, a great effort has been done to find out the new remedies for breast cancer. Main finding: Nanotechnology opened a new horizon to the treatment of breast cancer. Many nanoparticulate platforms for the diagnosis of involved biomarkers and delivering antineoplastic drugs are under either clinical trials or just approved by the Food and Drug Administration (FDA). It is well known that natural phytochemicals are successfully useful to treat breast cancer because these natural compounds are safer, available, cheaper, and have less toxic effects. Chitosan is a biocompatible and biodegradable polymer. Further, it has outstanding features, like chemical functional groups that can easily modify our interest with an exceptional choice of promising applications. Abundant studies were directed to assess the chitosan derivative-based nanoformulation's abilities in delivering varieties of drugs. However, the role of chitosan in diagnostics and theranostics not be obligated. The present servey will discuss the application of chitosan as an anticancer drug carrier such as tamoxifen, doxorubicin, paclitaxel, docetaxel, etc. and also, its role as a theranostics (i.e. photo-responsive and thermo-responsive) moieties. The therapeutic and theranostic potential of chitosan in cancer is promising and it seems that to have a good potential to get to the clinic.

A Magnetic T7 Peptide&AS1411 Aptamer-Modified Microemulsion for Triple Glioma-Targeted Delivery of Shikonin and Docetaxel

Glioma-targeted drug delivery is a hugely challenging task because of the multibarrier in the brain. In this study, we report a magnetic T7 peptide&AS1411 aptamer-modified microemulsion for triple glioma-targeted delivery of shikonin and docetaxel (Fe3O4@T7/AS1411/DTX&SKN-M). Such a system comprises two tumor-targeted ligands (T7 peptide and AS1411 aptamer), ultra-small superparamagnetic iron oxide nanoparticle (Fe3O4), and shikonin&docetaxel-coloaded microemulsion (SKN&DTX-M). Fe3O4@T7/AS1411/DTX&SKN-M is capable of stably circulating in the blood, accumulating around the brain under an external magnetic field, distributing inside the glioma via the affinity to nucleolin/transferrin receptor, and retarding the growth of orthotopic glioma. Fe3O4@T7/AS1411/DTX&SKN-M encapsulated Fe3O4 nanoparticles in the core to obtain the superparamagnetism, which did not influence the main surface properties. Introducing 6% (wt%) of DSPE-PEG2000-T7 and 180 nM of AS1411 collaboratively enhanced the murine glioma (G422) cellular uptake of Fe3O4@T7/AS1411/DTX&SKN-M and thereby achieved the strongest antiproliferation among all the groups. Notably, the drug distribution at the brain sites of orthotopic Luc-G422 glioma tumor-bearing nude mice treated with Fe3O4@T7/AS1411/DTX&SKN-M was overwhelming among all the treatments. Most importantly, Fe3O4@T7/AS1411/DTX&SKN-M not only significantly reduced the luminescence signal at the brain areas of orthotopic Luc-G422 glioma mice but also prolonged the overall survival period. The enhancement of anti-glioma efficacy was associated with down-regulating the population of CD133- and CD44-positive cells within the tumors. In summary, such a triple glioma-targeted delivery of shikonin and docetaxel using combinational magnetism and T7/AS1411 modification strategies provides a promising method for synergistic and precise glioma therapy.

Modular synthesis of amphiphilic chitosan derivatives based on copper-free click reaction for drug delivery

Amphiphilic chitosan derivatives have attracted wide attention as drug carriers due to their physicochemical properties. However, obtaining a desired amphiphilic chitosan derivative by tuning the various functional groups was complex and time-consuming. Therefore, a facile and common synthesis strategy would be promising. In this study, a modular strategy based on strain-promoted azide-alkyne cycloaddition (SPAAC) click reaction was designed and applied in synthesizing deoxycholic acid- or octanoic acid-modified N-azido propionyl-N,O-sulfate chitosan through tuning the hydrophobic groups. Additionally, chitosan derivatives with the same substitute groups were prepared via amide coupling as controls. We demonstrated that these derivates via the two strategies showed no obvious difference in physicochemical properties, drug loading ability and biosafety, indicating the feasibility of modular strategy. Notably, the modular strategy exhibited advantages including high reactivity, flexibility and reproducibility. We believe that this modular strategy could provide varied chitosan derivatives in an easy and high-efficiency way for improving multifunctional drug carriers.

Exploring the feasibility of carbamoylethyl pullulan-g-palmitic acid polymeric micelles for the effective targeting of raloxifene to breast tumor: Optimization and preclinical evaluation

Carbamoylethyl pullulan-grafted palmitic acid (CP-g-PA), a novel self-assembled polymer was synthesized and examined for its efficacy in delivering the raloxifene (RA) to mammary carcinoma. The synthesized CP-g-PA was confirmed by evaluating through various spectral and morphological attributes. Further, the central composite design-response surface methodology with two factors at three levels was utilized to obtain the optimized and stable polymeric micelles. The optimized formulation was subjected to in vitro and in vivo evaluation. RA loaded polymeric micelles (RA-PMs) were spherical in shape with particle size less than 100 nm and high entrapment efficiency (77.02%). The developed formulation exhibited pH-dependent release profile of RA when loaded in polymeric micelles and provides substantial compatibility to erythrocytes. In vivo pharmacokinetic study demonstrates that RA-PMs offers higher mean residence time and volume of distribution as compared to pure RA. Besides, the biodistribution study manifested enhanced drug concentration in tumor and decreased concentration in other tissue as compared to pure drug. The treatment with RA-PMs also increases the median survival time, tumor inhibition rate and % increase in life span of the tumor bearing rats. Overall, the results pointed towards the overwhelming response of RA when loaded into micelles made from CP-g-PA.

A multicomponent-based microemulsion for boosting ovarian cancer therapy through dual modification with transferrin and SA-R6H4

Balancing the antitumor activity and systemic toxicity of tripterine still faces a big challenge due to the narrow therapeutic window. To address this issue, we report a microemulsion system based on tripterine, brucea oil, and glycyrrhizin, and dual modified with both transferrin and cell-penetrating peptide SA-R₆H₄ (Tf/SA-R₆H₄-TBG-MEs) for combinational and tumor-targeted cancer therapy. Such a microemulsion exhibited a spherical shape with a size of ~50 nm and a mildly-negative charge. The half-maximal inhibitory concentration (IC₅₀) of Tf/SA-R₆H₄-TBG-MEs against ovarian cancer SKOV3 cells was 0.27 ± 0.43 μg tripterine/mL, which was 5.85 times lower than that of free tripterine. The cellular uptake of tripterine after treatment with Tf/SA-R₆H₄-TBG-MEs was 1.56 times higher than that of TBG-MEs (non-modified microemulsion). In pharmacokinetics studies, the area under the curve of Tf/SA-R₆H₄-TBG-MEs increased by 1.97 times compared with that of the physical mixture group. The tumoral accumulation of tripterine was significantly improved in Tf/SA-R₆H₄-TBG-MEs group than TBG-MEs-treated group. In antitumor efficacy in vivo, Tf/SA-R₆H₄-TBG-MEs exhibited the strongest inhibition of tumor growth and the longest survival period among all the groups, which is associated with the rational combination, microemulsion system, and dual modification with tumor-targeted ligands. Importantly, Tf/SA-R₆H₄-TBG-MEs significantly reduced the toxicity of tripterine against the liver and kidney. Our design provides a new approach for efficient and safe ovarian cancer therapy based on a multicomponent combination.

Anisamide-functionalized pH-responsive amphiphilic chitosan-based paclitaxel micelles for sigma-1 receptor targeted prostate cancer treatment

Controlled release and tumor-selective distribution are highly desirable for anticancer nanomedicines. Here, we design and synthesize an anisamide-conjugated N-octyl-N,O-maleoyl-O-phosphoryl chitosan (a-OMPC) which can form amphiphilic micelles featuring pH-responsive release and high affinity to sigma-1 receptor-overexpressed tumors for paclitaxel (PTX) delivery. Thereinto, maleoyl and phosphoryl groups cooperatively contribute to pH-responsive drug release due to a conversion from hydrophile to hydrophobe in the acidic microenvironment of endo/lysosomes. We demonstrated that PTX-loaded a-OMPC micelles (PTX-aM) enhanced the cellular internalization via the affinity between anisamide and sigma-1 receptor, rapidly released drug in endo/lysosomes and elevated the cytotoxicity against PC-3 cells. The in vivo studies further verified that PTX-aM could largely accumulate at the tumor site even after 24 h of administration, resulting in obvious inhibition effect and prolonged survival period in PC-3 tumor xenograft-bearing mice. Moreover, OMPC showed no obvious hemolytic and acute toxicity. Collectively, this chitosan derivate holds a promising potential in application of prostate cancer-targeted drug delivery system.

SYL3C aptamer-anchored microemulsion co-loading β-elemene and PTX enhances the treatment of colorectal cancer

The aim of this study is to construct a SYL3C aptamer-anchored microemulsion based on β-elemene and PTX (SYL3C/EP-MEs) for enhancement on colorectal cancer therapy. Such microemulsion is consist of encapsulated drugs (β-elemene and PTX), tumor targeting ligand (3’-end thiolated SYL3C aptamer), thiol conjugated site (maleimide-modified PEGylated 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine, mal-DOPE-PEG), pH-sensitive component (DOPE) and other necessary excipients. SYL3C/EP-MEs showed a spherical particle with an average particle size around 30 nm and a high encapsulation efficiency (>80%) for both drugs. β-elemene and PTX could be released controllably from SYL3C/EP-MEs as pH values changed. SYL3C/EP-MEs displayed a selective affinity to HT-29 cells, leading to an obvious increase in cellular uptake, cell apoptosis and cytotoxicity. In the HT-29 tumor xenograft-bearing nude mice model studies, SYL3C/EP-MEs showed an overwhelming tumor growth inhibition, the longest survival time and the lowest systemic toxicity among all the treatments. The potential mechanism of enhanced anti-cancer ability was probably associated with the induction of M1 macrophage polarization, the downregulation of mutant p53 protein and the reduction of bcl-2 protein expression. Collectively, the microemulsion codelivery of β-elemene and PTX using functionalization with SYL3C aptamer provides a novel approach for combinational colorectal cancer-targeted treatment.

AS1411 Aptamer/Hyaluronic Acid-Bifunctionalized Microemulsion Co-Loading Shikonin and Docetaxel for Enhanced Antiglioma Therapy

In this study, we developed an AS1411 aptamer/hyaluronic acid-bifunctionalized microemulsion co-loading shikonin and docetaxel (AS1411/SKN&DTX-M). Such microemulsion was capable of penetrating the blood-brain barrier (BBB), targeting CD44/nucleolin-overexpressed glioma, and inhibiting the orthotopic glioma growth. AS1411/SKN&DTX-M showed a spherical morphology with a diameter around 30 nm and rapidly released drugs in the presence of hyaluronidase and mild acid. In the U87 cellular studies, AS1411/SKN&DTX-M elevated the cytotoxicity, enhanced the cellular uptake, and induced the cell apoptosis. In the artificial blood-brain barrier model, the transepithelial electrical resistance was decreased after the treatment with AS1411/SKN&DTX-M and thereby of increasing the apparent permeability coefficient. Furthermore, AS1411/SKN&DTX-M showed a strong inhibition against the formation of cancer stem cell-enriched U87 cell spheroids, in which the expression of CD133 was downregulated significantly. In the biodistribution studies, AS1411/SKN&DTX-M could selectively accumulate in the brains of orthotopic luciferase-transfected U87 glioma tumor-bearing nude mice. Importantly, AS1411/SKN&DTX-M exhibited the overwhelming inhibition of glioma growth of orthotopic luciferase-transfected U87 glioma models and reached the longest survival period among all the treatments. In summary, the codelivery of shikonin and docetaxel using bifunctionalization with hyaluronic acid and AS1411 aptamer offers a promising strategy for dual drug-based combinational antiglioma treatment.

N-octyl chitosan derivatives as amphiphilic carrier agents for herbicide formulations

This study investigates the potential of N-octyl chitosan derivatives, namely N-octyl-O-sulfate chitosan (NOOSC), N-octyl-N-succinyl chitosan (NONSC) and N-octyl-O-glycol chitosan (NOOGC) as amphiphilic carrier agents for atrazine in water-insoluble herbicide formulations. The N-octyl chitosan derivatives were characterised using several analytical instruments such as Fourier Transform Infrared (FTIR) Spectrometer, CHNS-O Elemental Analyser (CHNS-O), Transmission Electron Microscope (TEM), Thermogravimetric Analyser (TGA), Differential Scanning Calorimeter (DSC) and Fluorescence Spectrometer. The encapsulation of atrazine by N-octyl chitosan derivatives was studied using a High Performance Liquid Chromatography (HPLC). The FTIR spectra of N-octyl chitosan derivatives confirmed the presence of hydrophobic and hydrophilic groups on chitosan backbone. TEM images revealed that N-octyl chitosan derivatives have formed self-aggregates with a spherical shape. The CMC values for N-octyl chitosan derivatives were between 0.06 and 0.09 mg/mL. The encapsulation efficiency (EE) values for amphiphilic chitosan were greater than 90%. The release profiles showed different release behaviour of pure herbicide in solution as compared to atrazine-loaded N-octyl chitosan derivatives. Results suggest that the chitosan derivatives offer promising characteristics that enable them to act as effective carrier agents for atrazine. In conclusion, the application of N-octyl chitosan derivatives could reduce the use of organic solvents in herbicide formulations by 37.5%.

Pep-1&borneol-Bifunctionalized Carmustine-Loaded Micelles Enhance Anti-Glioma Efficacy Through Tumor-Targeting and BBB-Penetrating

Tumor-targeting and blood-brain barrier (BBB)-penetrating are highly desirable for the treatment of glioma. In this study, we developed Pep-1&borneol-bifunctionalized carmustine-loaded micelles (Pep-1/Bor/CMS-M) capable of targeting interleukin-13 receptor-overexpressed glioma and penetrating the brain microvascular endothelial cells-associated physiologic barriers. Pep-1/Bor/CMS-M were nearly spherical particles with a diameter of 32.6 ± 1.1 nm and zeta potential of -21.3 ± 3.1 mV. Carmustine (CMS) released from Pep-1/Bor/CMS-M in pH 7.4 was significantly faster than in acidic environments. In human glioma BT325 cellular studies, Pep-1/Bor/CMS-M remarkably increased the cytotoxicity, notably improved the internalization, and effectively induced the cell apoptosis. Likewise, in human brain microvascular endothelial cells, Pep-1/Bor/CMS-M obviously promoted the cellular uptake, rapidly decreased the transepithelial electrical resistance, and thereby enhanced the ability of penetration. In orthotopic Luc-BT325 glioma tumor-bearing nude mouse models, the stronger fluorescence signal and longer retention were observed in brain tissues compared with other controls, after single administration of DiD-labeled Pep-1/Bor/M (DiD/Pep-1/Bor/M). Importantly, Pep-1/Bor/CMS-M displayed the strongest inhibition of tumor growth, the longest survival period, and low systemic toxicity in treating orthotopic glioma tumor-bearing nude mice. Simultaneous functionalization of Pep-1 and borneol offers a novel strategy for designing CMS-based nanomedicine and precisely treating glioma.

Estrone-modified pH-sensitive glycol chitosan nanoparticles for drug delivery in breast cancer

Estrone-modified glycol chitosan nanoparticles (GCNP-ES) based on the mechanisms of ES-mediated endocytosis and intracellular pH-responsive drug release were developed for the treatment of breast cancer. GCNP-ES were prepared by grafting copolymerization of glycol chitosan with 2-(diisopropylamino)ethyl methacrylate to generate GCNP prior to ES conjugation. The particle size, zeta potential, and paclitaxel (PTX) encapsulation efficiency of GCNP-ES were characterized. In particular, GCNP-ES exhibited pH-responsive dissociation properties while maintaining stability under long-term storage and lyophilization. The drug release of PTX-loaded GCNP-ES (PTX/GNCP-ES) was modestly prolonged with considerable pH sensitivity. GCNP-ES promoted internalization in breast cancer MCF-7 cells by approximately 5-fold as compared to GCNP, and the internalized GCNP-ES was mainly localized in the endosomes of MCF-7 cells. PTX/GNCP-ES exhibited higher cytotoxicity and cell apoptosis ratio than GCNP. In mice with MCF-7 breast cancer xenograft, PTX/GCNP-ES showed higher accumulation at the tumor site, which resulted in a higher tumor inhibition ratio (81.4%) than that achieved by PTX/GCNP (69.4%) and PTX solution (48.8%). Furthermore, no histological and hematological toxicity was detected in in vivo studies of PTX/GCNP-ES. Overall, these results suggested the potential applicability of GCNP-ES as a drug delivery system for breast cancer therapy.

STATEMENT OF SIGNIFICANCE

Most breast cancers are hormone dependent. Herein, we developed a estrone-modified glycol chitosan nanoparticles (GCNP-ES) as a drug delivery system to overcome the drawbacks of chemotherpeutic drugs, including poor water solubility and lack of specifity. GCNP-ES could provide efficient drug delivery in breast cancer cells. The study demonstrated that GCNP-ES could dissociate under mildly acidic conditions, leading to the timely payload release of the drug in target tumor cells following internalization. The conjugated estrone of the nanoparticles could significantly increase drug accumulation in the tumor site and result in enhanced therapeutic effect. Thus, the potential applicability of GCNP-ES was suggested.

A multicomponent microemulsion using rational combination strategy improves lung cancer treatment through synergistic effects and deep tumor penetration

Previously, we have developed a multicomponent-based microemulsion composed of etoposide, coix seed oil, and ginsenoside Rh2 (ECG-MEs). In this study, our goal was to validate the feasibility of ECG-MEs in lung cancer treatment and explore the mechanism underling the enhanced antitumor efficacy. The optimal weight ratio of ginsenoside Rh2 (G-Rh2) in ECG-MEs was determined as 3% (wt%), that was capable of forming the microemulsion readily with small particle size and high drug encapsulation efficiency. In cellular studies, the intracellular fluorescence of human non-small cell lung cancer (A549) cells treated with fluorescein isothiocyanate-labeled ECG-MEs (FITC/ECG-MEs) was significantly higher than that of various controls, leading to the obviously synergistic anticancer activities in cytotoxicity and in vitro cell apoptosis induction. The anticancer efficacy in vivo results showed that ECG-MEs markedly inhibited the growth of A549 tumor xenografts, potently induced tumor cells apoptosis, and obviously prolonged the survival time of mice. Of note, the mechanisms of enhanced anticancer efficiency were connected with the small size-mediated deep tumor penetration and increase in serum concentration of T helper 1 (Th1) cytokines. In summary, ECG-MEs exerting the rational drug combination strategy offers a solid evidence for lung cancer treatment, and has a promising potential for clinical application.

Natural material-decorated mesoporous silica nanoparticle container for multifunctional membrane-controlled targeted drug delivery

To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs), which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS) which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD44 receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy.

Preliminary study on fabrication, characterization and synergistic anti-lung cancer effects of self-assembled micelles of covalently conjugated celastrol-polyethylene glycol-ginsenoside Rh2

The aim of this study was to develop an amphipathic polyethylene glycol (PEG) derivative that was bi-terminally modified with celastrol and ginsenoside Rh2 (Celastrol-PEG-G Rh2). Such derivative was capable of forming novel, celastrol-loaded polymeric micelles (CG-M) for endo/lysosomal delivery and thereby synergistic treatment of lung cancer. Celastrol-PEG-G Rh2 with a yield of 55.6% was first synthesized and characterized. Its critical micellar concentration was 1 × 10-5 M, determined by pyrene entrapment method. CG-M had a small particle size of 121.53 ± 2.35 nm, a narrow polydispersity index of 0.214 ± 0.001 and a moderately negative zeta potential of -23.14 ± 3.15 mV. Celastrol and G Rh2 were rapidly released from CG-M under acidic and enzymatic conditions, but slowly released in normal physiological environments. In cellular studies, the internalization of celastrol and G Rh2 by human non-small cell lung cancer (A549) cells treated with CG-M was 5.8-fold and 1.8-fold higher than that of non-micelle control. Combinational therapy of celastrol and G Rh2 using CG-M exhibited synergistic anticancer activities in cell apoptosis and proliferation assays via rapid drug release within endo/lysosomes. Most importantly, the celastrol in CG-M exhibited a long elimination half-life of 445.3 ± 43.5 min and an improved area under the curve of 645060.8 ± 63640.7 ng/mL/h, that were 1.03-fold and 2.44-fold greater than those of non-micelle control, respectively. These findings suggest that CG-M is a promising vector for precisely releasing anticancer drugs within the tumor cells, and thereby exerts an improved synergistic anti-lung cancer effect.

A microemulsion co-loaded with Schizandrin A-docetaxel enhances esophageal carcinoma treatment through overcoming multidrug resistance

Multidrug resistance (MDR) is the major underlying cause of the low 5-year survival rate of esophageal carcinoma. In this study, we developed a novel microemulsion system (SD-ME) co-loaded with docetaxel (DTX) and Schizandrin A, a potent chemotherapeutic agent and a potential drug resistance modulator, respectively. In the physicochemical characterization studies, SD-ME displayed a well-defined spherical shape and size (56.62 ± 4.16 nm), a narrow polydispersity index (PDI, 0.132 ± 0.002), and a negative surface charge (−19.81 ± 3.11 mv). In the cellular uptake studies, SD-ME with a DTX concentration of 30 μg/mL exhibited a 3.9-fold enhancement of DTX internalization in DTX-resistant EC109 (EC109/DDR) cells in comparison to that observed for EC109 cells, and the mechanisms were associated with reducing P-gp expression and inhibiting P-gp ATPease. The half-maximal inhibitory concentrations (IC₅₀) of DTX and SD-ME against EC109/DDR cells were 40.57 ± 0.39 and 3.59 ± 0.06 μg/mL, respectively. Likewise, the apoptotic rate of EC109/DDR treated with SD-ME increased up to 20-fold compared to that observed with free DTX. In anticancer efficacy studies in vivo, SD-ME markedly retarded the tumor growth of nude mice bearing EC109/DDR tumor xenografts compared with D-ME and free DTX throughout the duration of study. Consequently, mice treated with SD-ME had the highest survival rate (37.5%) during the observation period (70 days). In addition, there were no apparent side effects after the administration of SD-ME. Overall, our study provides evidence for SD-ME as an effective drug delivery system for enhanced MDR tumor treatment.

Octanoyl galactose ester-modified microemulsion system self-assembled by coix seed components to enhance tumor targeting and hepatoma therapy

A nanosized drug delivery platform with a combination of rational components and tumor targeting is significant for enhancement of anticancer therapy and reduction of side effects. In this study, we developed a octanoyl galactose ester-modified microemulsion system self-assembled by coix seed components (Gal(oct)-C-MEs), which improved the tumor accumulation through asialoglycoprotein receptor-mediated endocytosis and promoted the antitumor efficacy through multicomponent-mediated synergistic effect. Octanoyl galactose ester (Gal(oct)) with a yield of 82.3% was synthesized through a green enzymatic reaction and multidimensional characterization. Gal(oct)-C-MEs with a spherical shape had a small and uniform particle size (58.49±1.03 nm), narrow polydispersity index (0.09±0.01) and neutral surface charge (-5.82±0.57 mV). In the cellular uptake studies, the internalized Gal(oct)-C-ME was 2.28-fold higher relative to that of coix seed component-based microemulsions (C-MEs). The half-maximal inhibitory concentration of Gal(oct)-C-MEs against HepG2 cells was 46.5±2.4 μg/mL, which was notably higher than that of C-MEs. Importantly, the intratumor fluorescence of HepG2 xenograft-bearing nude mice treated with Cy5/Gal(oct)-C-MEs was 1.9-fold higher relative to treatment with Cy5/C-MEs. In the study of antitumor efficacy in vivo, HepG2 xenograft-bearing nude mice intragastrically administered Gal(oct)-C-MEs for 14 days exhibited the strongest inhibition of tumor growth and the lowest toxicity against liver and kidney among all the treatments. In summary, Gal(oct)-C-ME, as a highly effective and safe anticancer drug delivery system, showed promising potential for hepatoma therapy.

Loading of anthocyanins on chitosan nanoparticles influences anthocyanin degradation in gastrointestinal fluids and stability in a beverage

The optimal preparation parameters to create anthocyanin-loaded chitosan nanoparticles was predicted using response surface methodology (RSM). A Box-Behnken design was used to determine the preparation parameters that would achieve the preferred particle size and high encapsulation efficiency. The result suggested that the optimized conditions were 2.86mg/mL carboxymethyl chitosan (CMC), 0.98mg/mL chitosan hydrochloride (CHC) and 5.97mg anthocyanins. Using the predicted amounts, the experimentally prepared particles averaged 219.53nm with 63.15% encapsulation efficiency. The result was less than 5% different than the predicted result of 214.83nm particle size and 61.80% encapsulation efficiency. Compared with the free anthocyanin solution, the anthocyanin-loaded chitosan nanoparticles showed a slowed degradation in simulated gastrointestinal fluid. Compared with the free anthocyanin solutions in a model beverage system, the stability of the anthocyanins was increased in the anthocyanin-loaded chitosan nanoparticles.

A novel preparation method of paclitaxcel-loaded folate-modified chitosan microparticles and in vitro evaluation

A new chitosan microparticles loading paclitaxel (PTX) for application as an oral delivery system were developed using a novel double emulsion crosslinking method. To improve the targeted effect, folic acid (FA) was introduced onto the surface of microparticles using chemical method. The method was based on Schiff reaction between amino group of chitosan and carboxyl group of FA, and folate-chitosan (FA-CS) conjugate was characterized using infrared spectrum analysis (FT-IR), and the microparticles were named as FA-CS-PTX/MPs. FA-CS-PTX/MPs had larger size of average diameter 223.6 nm, while PTX-loaded chitosan microparticles (CS-PTX/MPs) had 179.1 nm average diameter. The zeta potential of CS-PTX/MPs and FA-CS-PTX/MPs was 22.3 and 33.1 mV, respectively. SEM and TEM showed both the two microparticles had well-defined spherical structure. The in vitro drug release was studied under different pH conditions, and a two-phase kinetics model was found to be the most adequate kinetic model. Furthermore, the cytotoxicity activities of drug-carriers against L929 cells and the cellular uptake of PTX-loaded microparticles against HepG2 cells were investigated. Results demonstrated that FA-CS-PTX/MPs might be a promising drug carrier for promoting PTX cellular uptake and could be used as a potential tumor-targeted drug vector.

Systemic delivery of micelles loading with paclitaxel using N-succinyl-palmitoyl-chitosan decorated with cRGDyK peptide to inhibit non-small-cell lung cancer

This study aimed to prepare efficient cRGDyK peptide-decorated micelles for the targeted therapy of non-small-cell lung cancer (NSCLC). An amphiphilic copolymer N-succinyl-palmitoyl-chitosan (SPCS) was synthesized and characterized. cRGDyK peptide is a ligand that can target tumors via specific binding integrin receptor overexpressed on tumor neovascularization and cells. cRGDyK-functionalized SPCS micelles loaded with paclitaxel (PTX/cRGDyK-SPCS) were prepared by film dispersion method and then characterized according to morphology, size, and zeta potential. PTX/cRGDyK-SPCS micelles presented pH-triggered drug release behavior under acidic conditions. The accumulation of micelles detected by laser confocal fluorescence microscopy and flow cytometry showed that cRGDyK-SPCS micelles were easily taken up by A549 cells marked with the luciferase gene (luc-A549). Meanwhile, co-localization of the micelles and lysosomes was recorded dynamically using a live cell station. MTT assays and cell apoptosis studies revealed that cell viability was significantly inhibited by PTX/cRGDyK-SPCS micelles. More importantly, in vivo animal studies showed that cRGDyK-SPCS micelles mainly accumulated in the orthotopic tumor site. PTX/cRGDyK-SPCS micelles exhibited better anti-tumor activity in subcutaneous and orthotopic lung tumors compared with PTX/SPCS micelles and Taxol(®). These results suggested that PTX/cRGDyK-SPCS micelles had better cancer targeting capacity and superior anti-tumor efficacy. Thus, these micelles have great potential as novel carriers in delivering anti-tumor drugs.

Encapsulation of honokiol into self-assembled pectin nanoparticles for drug delivery to HepG2 cells

Self-assembled pectin nanoparticles was prepared and evaluated for delivering the hydrophobic drug, honokiol (HK), to HepG2 cells. These hydrophobic drug-loaded nanoparticles were developed without using any surfactant and organic solvent. Hydroxypropyl-β-cyclodextrin (HCD) was used to fabricate an inclusion complex with HK (HKHCD) to increase the solubility of the drug and thus facilitate its encapsulation and dispersion in the pectin nanoparticles. Investigation of the in vitro release indicated that the drug-loaded nanoparticles exhibited a higher drug release rate than free honokiol and an effective sustained-release. Cytotoxicity, cell apoptosis and cellular uptake studies further confirmed that the pectin nanoparticles with galactose residues generated higher cytotoxicity than free honokiol on HepG2 cells which highly expressed asialoglycoprotein receptors (ASGR). Nevertheless, these findings were not observed in ASGR-negative A549 cells under similar condition. Therefore, pectin nanoparticles demonstrated a specific active targeting ability to ASGR-positive HepG2 cells and could be used as a potential drug carrier for treatment of liver-related tumors.

Effects of triglycerides on the hydrophobic drug loading capacity of saturated phosphatidylcholine-based liposomes

A high drug-loading capacity is a critical factor for the clinical development of liposomal formulations. The accommodation of hydrophobic drugs within the liposomal membrane is often limited in saturated phosphatidylcholine (PC)-based liposomes owing to the rigidity of the lipid acyl chain. In the current study, we explored the possibility of improving the hydrophobic drug loading capacity of liposomes by incorporating triglyceride into liposomal membranes. Incorporation of Captex 300, a medium chain triglyceride, into liposomes composed of dimyristoylphosphatidylcholine and cholesterol greatly increased the fluidity and lamellarity of the resultant liposomes. Liposomal incorporation of medium or long chain, but not short chain, triglycerides greatly enhanced the concentration of loaded paclitaxel (PTX) in saturated PC-based liposomes. The enhancing effect of triglyceride saturated at a triglyceride content corresponding to the amount required to fluidize the liposome structure. In addition, the enhancing effect was not observed in unsaturated PC-based liposomes and was not associated with the solubility of PTX in each triglyceride. Triglycerides also enhanced the loading of docetaxel, another hydrophobic drug. Taken together, our results suggest that triglyceride incorporation in saturated PC-based liposomes provide an improved dosage form that enables increased hydrophobic drug loading by altering the fluidity and structure of liposomal membranes.

Microemulsion-based synergistic dual-drug codelivery system for enhanced apoptosis of tumor cells

A microemulsion-based synergistic dual-drug codelivery system was developed for enhanced cell apoptosis by transporting coix seed oil and etoposide into A549 (human lung carcinoma) cells simultaneously. Results obtained by dynamic light scattering showed that an etoposide (VP16)-loaded coix seed oil microemulsion (EC-ME) delivery system had a small size around 35 nm, a narrow polydispersity index, and a slightly negative surface charge. The encapsulating efficiency and total drug loading rate were 97.01% and 45.48%, respectively, by high-performance liquid chromatography. The release profiles at various pH values showed an obvious pH-responsive difference, with the accumulated amount of VP16 released at pH 4.5 (and pH 5.5) being 2.7-fold higher relative to that at pH 7.4. Morphologic alteration (particle swelling) associated with a mildly acidic pH environment was found on transmission electron microscopy. In the cell study, the EC-ME system showed a significantly greater antiproliferative effect toward A549 cells in comparison with free VP16 and the mixture of VP16 and coix seed oil. The half-maximal inhibitory concentration of the EC-ME system was 3.9-fold and 10.4-fold lower relative to that of free VP16 and a mixture of VP16 and coix seed oil, respectively. Moreover, fluorescein isothiocyanate and VP16 (the green fluorescent probe and entrapped drug, respectively) were efficiently internalized into the cells by means of coix seed oil microemulsion through intuitive observation and quantitative measurement. Importantly, an EC-ME system containing 20 μg/mL of VP16 showed a 3.3-fold and 3.5-fold improvement in induction of cell apoptosis compared with the VP-16-loaded microemulsion and free VP16, respectively. The EC-ME combination strategy holds promise as an efficient drug delivery system for induction of apoptosis and treatment of lung cancer.

Immunosafety and chronic toxicity evaluation of monomethoxypoly(ethylene glycol)-b-poly(lactic acid) polymer micelles for paclitaxel delivery

To investigate the physicochemical properties, immunosafety and chronic toxicity of monomethoxypoly(ethylene glycol)-b-poly(lactic acid) (mPEG-PLA), a copolymer used as a carrier for paclitaxel (PTX) delivery. The H-Nuclear Magnetic Resonance (H-NMR), dynamic light scattering and fluorescence probe technique were conducted to determine the physicochemical properties of mPEG-PLA copolymer. PTX-loaded polymeric micelles were characterized regarding their particle size, entrapment efficiency (EE), drug loading (DL), in vitro drug release and hemolysis rate. The complement activation in human serum and mast cells degranulation were performed by ELISA and RBL-2H3 cell line in vitro, respectively. The chronic toxicity study was carried out on beagle dogs. The optimized PTX-loaded mPEG-PLA (40/60) micelles showed a particle size of 37 nm and EE of 98.0% with a DL of 17.0% w/w. Transmission electron microscopy (TEM) analyses showed that mPEG-PLA (40/60) micelles have spherical shape with dense core. In vitro release study showed a sustained release for 24 h, and the hemolysis study revealed that mPEG-PLA (40/60) was a safe nanocarrier for intravenous administration. mPEG-PLA (40/60) showed a lower complement activation ability compared to mPEG-PLA (50/50) and Cremophor® EL (Cr EL). Furthermore, the chronic toxicity of PTX-loaded mPEG-PLA (40/60) micelles was significantly lower than those of mPEG-PLA (50/50) and Cr EL.

Molecular and engineering approaches to regenerate and repair teeth in mammals

Continuous replacement of teeth throughout the lifespan of an individual is possibly basal for most of the vertebrates including fish and reptiles; however, mammals generally have a limited capacity of tooth renewal. The ability to induce cellular differentiation in adults to replace lost or damaged cells in mammals, or to tissue-engineer organs in vitro, has hence become one of the major goals of regenerative medicine. In this article, we will revisit some of the important signals and tissue interactions that regulate mammalian tooth development, and will offer a synopsis of the latest progress in tooth regeneration and repair via molecular and engineering approaches. It is hoped that this article will not only offer an overview of recent technologies in tooth regeneration and repair but will also stimulate more interdisciplinary research in this field to turn the pursuit of tooth regeneration and repair into practical reality.

Effect of silanization on chitosan porous scaffolds for peripheral nerve regeneration

The aim of this study was to evaluate the feasibility of using 3-aminopropyltriethoxysilane (APTE) silanization treatment for modification and biocompatibility of lyophilized chitosan porous scaffolds. The process is beneficial for biomaterial development due to its low toxicity and simplicity. The silanization treatment with low APTE concentration showed no significant influence on the morphology of chitosan scaffolds, while a skin-like surface was observed for the silanized scaffolds treated with high APTE concentration. The porosity and surface amino densities were increased after silanization whereas the swelling ratio was reduced, and the degradation ratio in PBS and anti-acid degradation properties of the silanized chitosan scaffolds were significantly improved. The in vitro Schwann cells culture demonstrated that the silanized scaffolds with 8% APTE could obviously facilitate the attachment and proliferation of Schwann cells, indicating great potential for the application in peripheral nerve regeneration.