Stabilizing BiVO4 Photoanode in Bicarbonate Electrolyte for Efficient Photoelectrocatalytic Alcohol Oxidation.

In order to expand the application of bismuth vanadate (BiVO4) to the field of photoelectrochemistry, researchers have explored the potential of BiVO4 in catalyzing or degrading organic substances, potentially presenting a green and eco-friendly solution. A study was conducted to investigate the impact of electrolytes on the photocatalysis of benzyl alcohol by BiVO4. The research discovered that, in an acetonitrile electrolyte (pH 9) with sodium bicarbonate, BiVO4 catalyzed benzyl alcohol by introducing saturated V5+. This innovation addressed the issue of benzyl alcohol being susceptible to catalysis in an alkaline setting, as V5+ was prone to dissolution in pH 9 on BiVO4. The concern of the photocorrosion of BiVO4 was mitigated through two approaches. Firstly, the incorporation of a non-aqueous medium inhibited the formation of active material intermediates, reducing the susceptibility of the electrode surface to photocorrosion. Secondly, the presence of saturated V5+ further deterred the leaching of V5+. Concurrently, the production of carbonate radicals by bicarbonate played a vital role in catalyzing benzyl alcohol. The results show that, in this system, BiVO4 has the potential to oxidize benzyl alcohol by photocatalysis.

Recent Progress of Remediating Heavy Metal Contaminated Soil Using Layered Double Hydroxides as Super-Stable Mineralizer.

Heavy metal contamination in soil, which is harmful to both ecosystem and mankind, has attracted worldwide attention from the academic and industrial communities. However, the most-widely used remediation technologies such as electrochemistry, elution, and phytoremediation. suffer from either secondary pollution, long cycle time or high cost. In contrast, in situ mineralization technology shows great potential due to its universality, durability and economical efficiency. As such, the development of mineralizers with both high efficiency and low-cost is the core of in situmineralization. In 2021, the concept of 'Super-Stable Mineralization' was proposed for the first time by Kong et al.[1] The layered double hydroxides (denoted as LDHs), with the unique host-guest intercalated structure and multiple interactions between the host laminate and the guest anions, are considered as an ideal class of materials for super-stable mineralization. In this review, we systematically summarize the application of LDHs in the treatment of heavy metal contaminated soil from the view of: 1) the structure-activity relationship of LDHs in in situ mineralization, 2) the advantages of LDHs in mineralizing heavy metals, 3) the scale-up preparation of LDHs-based mineralizers and 4) the practical application of LDHs in treating contaminated soil. At last, we highlight the challenges and opportunities for the rational design of LDH-based mineralizer in the future.

Insight into the In-Situ Encapsulation-Reassembly Strategy To Fabricate PW12@NiCo-LDH Acid-Base Bifunctional Catalysts.

Acid-base bifunctional catalysts have attracted increasing attention due to the improved overall efficiency of synthetic reactions. Herein, we reported the successful fabrication of a PW12@NiCo-LDH acid-base bifunctional catalyst by using the in-situ encapsulation-reassembly strategy. The evolution process of morphology and structure was monitored carefully by various time-dependent characterizations. X-ray absorption fine structure (XAFS) and density functional theory (DFT) calculations demonstrated that the terminal oxygen of PW12 in PW12@NiCo-LDH preferred to assemble with the oxygen vacancies on NiCo-LDH. When applied for deacetalization-Knoevenagel condensation, the PW12@NiCo-LDH displayed >99% conversion of benzaldehyde dimethyl acetal (BDMA) and >99% yield of ethyl α-cyanocinnamate (ECC). Moreover, PW12@NiCo-LDH can be recycled at least 10 cycles without obvious structural change, which can be attributed to the confinement of PW12 into the NiCo-LDH nanocage. Such excellent catalytic activity of PW12@NiCo-LDH was benefited from the short mass transfer pathway between acid sites and base sites, which was caused by the stable assembly between PW12 and NiCo-LDH.

Regulating Hollow Carbon Cage Supported NiCo Alloy Nanoparticles for Efficient Electrocatalytic Hydrogen Evolution Reaction.

The NiCo alloy is one of the most promising alternatives to the noble-metal electrocatalysts for the hydrogen evolution reaction (HER); however, its performance is largely restricted by insufficient active sites and low surface area. Here, we fabricated a hierarchical hollow carbon cage supported NiCo alloy (denoted as HC NiCo/C) and a bulk NiCo alloy (denoted as NiCo) by reduction of a partially ZIF-67 etched ZIF-67@NiCo-LDH (LDH = layered double hydroxide) precursor and a fully ZIF-67 etched NiCo-LDH precursor, respectively. The as-prepared HC NiCo/C, in which the Ni29Co71 alloy nanocrystals with an average 6 nm size were encapsulated in graphitic carbon layers, provided a vastly increased electrochemically active surface area (ca. 13 times than the NiCo) and abundant catalytic active sites, which resulted in a higher HER performance with an overpotential of 99 mV than the 198 mV for NiCo at 10 mA cm-2. Detailed experimental results suggested that only the HC NiCo/C possessed the active alloy surface composed of unsaturated Ni0 and Co0 atoms, and both the metal-support interaction and alloying effect influenced the electronic structure of Co and Ni in HC NiCo/C, whereas the NiCo exhibited pure Ni surface. Theoretical calculations further revealed the Ni29Co71 alloy surface in HC NiCo/C possessed the appropriate adsorption energy of the intermediate state (adsorbed H*). This work provided new insight into the construction of the stable small-sized bimetallic alloy nanocatalysts by regulating the reduction precursors.

Detecting the Subtle Photo-Responsive Conformational Bistability of Monomeric Azobenzene Functionalized Keggin Polyoxometalates by Using Ion-Mobility Mass Spectrometry.

Accurately characterizing the conformational variation of novel molecular assemblies is important but often ignored due to limited characterization methods. Herein, we reported the use of ion-mobility mass spectrometry (IMS/MS) to investigate the conformational changes of four azobenzene covalently functionalized Keggin hybrids (azo-Keggins, compounds 1-4). The as-prepared azo-Keggins showed the general molecular formula of [C16H36N]4[SiW11O40(Si(CH2)3NH-CO(CH2)nO-C6H4N=NC6H4-R)2] (R = H, n = 0 (1); R = NO2, n = 0 (2); R = H, n = 5 (3); R = H, n = 10 (4)). The resultant azo-Keggins maintained stable monomeric states in the gas phase with intact molecular structures. Furthermore, the subtle photo-responsive trans-cis conformational variations of azo-Keggins were clearly revealed by the molecular shape-related collision cross-section value difference ranging from 2.44 Å2 to 6.91 Å2. The longer the alkyl chains linkers were, the larger the conformational variation was. Moreover, for compounds 1 and 2, higher stability in trans-conformation can be observed, while for compounds 3 and 4, bistability can be achieved for both of them.

In Situ Construction of MIL-100@NiMn-LDH Hierarchical Architectures for Highly Selective Photoreduction of CO2 to CH4.

Layered double hydroxides (LDHs) are considered a promising catalyst for photocatalytic CO2 reduction due to their broad photoresponse, facile channels for electron transfer, and the presence of abundant defects. Herein, we reported for the first time the fabrication of a novel photocatalyst MIL-100@NiMn-LDH with a hierarchical architecture by selecting MIL-100 (Mn) as a template to provide Mn3+ for the in situ growth of ultrathin NiMn-LDH nanosheets. Moreover, the in situ growth strategy exhibited excellent universality toward constructing MIL-100@LDH hierarchical architectures. When applied in the photocatalytic CO2 reduction reaction, the as-prepared MIL-100@NiMn-LDH exhibited excellent CH4 selectivity of 88.8% (2.84 µmol h-1), while the selectivity of H2 was reduced to 1.8% under visible light irradiation (λ > 500 nm). Such excellent catalytic performance can be attributed to the fact that (a) the MIL-100@NiMn-LDH hierarchical architectures with exposed catalytic active sites helped to enhance the CO2 adsorption and activation and (b) the presence of rich oxygen vacancies and coordinately unsaturated metal sites in MIL-100@NiMn-LDH that optimized the band gap and accelerated the separation/transport of photoinduced charges.

GM-CSF mediates immune evasion via upregulation of PD-L1 expression in extranodal natural killer/T cell lymphoma.

BACKGROUND: Granulocyte-macrophage colony stimulating factor (GM-CSF) is a cytokine that is used as an immunopotentiator for anti-tumor therapies in recent years. We found that some of the extranodal natural killer/T cell lymphoma (ENKTL) patients with the treatment of hGM-CSF rapidly experienced disease progression, but the underlying mechanisms remain to be elucidated. Here, we aimed to explore the mechanisms of disease progression triggered by GM-CSF in ENKTL. METHODS: The mouse models bearing EL4 cell tumors were established to investigate the effects of GM-CSF on tumor growth and T cell infiltration and function. Human ENKTL cell lines including NK-YS, SNK-6, and SNT-8 were used to explore the expression of programmed death-ligand 1 (PD-L1) induced by GM-CSF. To further study the mechanisms of disease progression of ENKTL in detail, the mutations and gene expression profile were examined by next-generation sequence (NGS) in the ENKTL patient's tumor tissue samples. RESULTS: The mouse-bearing EL4 cell tumor exhibited a faster tumor growth rate and poorer survival in the treatment with GM-CSF alone than in treatment with IgG or the combination of GM-CSF and PD-1 antibody. The PD-L1 expression at mRNA and protein levels was significantly increased in ENKTL cells treated with GM-CSF. STAT5A high-frequency mutation including p.R131G, p.D475N, p.F706fs, p.V707E, and p.S710F was found in 12 ENKTL cases with baseline tissue samples. Importantly, STAT5A-V706fs mutation tumor cells exhibited increased activation of STAT5A pathway and PD-L1 overexpression in the presence of GM-CSF. CONCLUSIONS: These findings demonstrate that GM-CSF potentially triggers the loss of tumor immune surveillance in ENKTL patients and promotes disease progression, which is associated with STAT5 mutations and JAK2 hyperphosphorylation and then upregulates the expression of PD-L1. These may provide new concepts for GM-CSF application and new strategies for the treatment of ENKTL.

Enhanced Macroanion Recognition of Superchaotropic Keggin Clusters Achieved by Synergy of Anion-π and Anion-Cation Interactions.

Keggin clusters are the most widely used polyoxometalate building blocks for the construction advanced materials, but effective methods for precisely recognizing the isostructural analogues of Keggins are still limited. In this study we employed the zwitterionic molecule 4,4'-dipyridyl N,N'-dioxide as a recognition receptor to specifically bind to the three Keggin analogues PW12 O40 3- , PMo12 O40 3- , and SiW12 O40 4- , which separately co-assembled into three different types of spherical charged colloids of different sizes. The recognition phenomena were confirmed by electrochemical methods and their crystallization behavior. Compared with solely anion-cation interaction-driven systems, the synergism with the anion-π interactions between the superchaotropic Keggins and the electron-deficient pyridine rings is believed to enhance the recognition. This observation is intriguing as the long-range solution assembly of Keggins is mainly driven by short-range anion-π interactions. Our results show that the little-noticed hydration shell of Keggins is significantly influenced by the superchaotropic effect, leading to differentiated binding affinity to the receptors and more obvious recognition phenomena between tungsten/molybdenum Keggin analogues.

Nano-puerarin regulates tumor microenvironment and facilitates chemo- and immunotherapy in murine triple negative breast cancer model.

Tumor associated fibroblasts (TAFs) are key stromal cells mediating the desmoplastic reaction and being partially responsible for the drug-resistance and immunosuppressive microenvironment formation in solid tumors. Delivery of genotoxic drugs off-targetedly to kill TAFs results in production of Wnt16 which renders the neighboring tumor cells drug resistant as shown in our previous study (PMC4623876). Our current approach looks for means to deactivate, rather than kill, TAFs. Reactive oxygen species (ROS) are the central hub of multiple profibrogenic pathways and indispensable for TAFs activation. Herein, puerarin was identified to effectively downregulate ROS production in the activated myofibroblast. In this study, a novel puerarin nanoemulsion (nanoPue) was developed to improve the solubility and bioavailability of puerarin. NanoPue significantly deactivated the stromal microenvironment (e.g., ~6-fold reduction of TAFs in nanoPue treated mice compared with the PBS control, p < 0.0001) and facilitated chemotherapy effect of nano-paclitaxel in the desmoplastic triple-negative breast cancer (TNBC) model. Moreover, the removal of the physical barrier increased intra-tumoral infiltration of cytotoxic T cell by 2-fold. This activated immune microenvironment allowed nanoPue to synergize PD-L1 blockade therapy in TNBC model.

Relaxin gene delivery mitigates liver metastasis and synergizes with check point therapy.

Activated hepatic stellate cell (aHSC)-mediated liver fibrosis is essential to the development of liver metastasis. Here, we discover intra-hepatic scale-up of relaxin (RLN, an anti-fibrotic peptide) in response to fibrosis along with the upregulation of its primary receptor (RXFP1) on aHSCs. The elevated expression of RLN serves as a natural regulator to deactivate aHSCs and resolve liver fibrosis. Therefore, we hypothesize this endogenous liver fibrosis repair mechanism can be leveraged for liver metastasis treatment via enforced RLN expression. To validate the therapeutic potential, we utilize aminoethyl anisamide-conjugated lipid-calcium-phosphate nanoparticles to deliver plasmid DNA encoding RLN. The nanoparticles preferentially target metastatic tumor cells and aHSCs within the metastatic lesion and convert them as an in situ RLN depot. Expressed RLN reverses the stromal microenvironment, which makes it unfavorable for established liver metastasis to grow. In colorectal, pancreatic, and breast cancer liver metastasis models, we confirm the RLN gene therapy results in significant inhibition of metastatic progression and prolongs survival. In addition, enforced RLN expression reactivates intra-metastasis immune milieu. The combination of the RLN gene therapy with PD-L1 blockade immunotherapy further produces a synergistic anti-metastatic efficacy. Collectively, the targeted RLN gene therapy represents a highly efficient, safe, and versatile anti-metastatic modality, and is promising for clinical translation.

Locally Trapping the C-C Chemokine Receptor Type 7 by Gene Delivery Nanoparticle Inhibits Lymphatic Metastasis Prior to Tumor Resection.

Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype. Currently, no targeted treatment is available for TNBC, and the most common clinical therapy is tumor resection, which often promotes metastasis risks. Strong evidence suggests that the lymphatic metastasis is mediated by the C-C chemokine receptor type 7 (CCR7)/C-C motif chemokine ligand 21 crosstalk between tumor cells and the lymphatic system. It is hypothesized that CCR7 is a key immune modulator in the tumor microenvironment and the local blockade of CCR7 could effectively inhibit TNBC lymphatic metastasis. Accordingly, a plasmid encoding an antagonistic CCR7 affinity protein-CCR7 trap is delivered by tumor targeting nanoparticles in a highly metastatic 4T1 TNBC mouse model. Results show that CCR7 traps are transiently expressed, locally disrupt the signaling pathways in the tumor site, and efficiently inhibit TNBC lymphatic metastasis, without inducing immunosuppression as observed in systemic therapies using CCR7 monoclonal antibody. Significantly, upon applying CCR7 trap therapy prior to tumor resection, a 4T1 TNBC mouse model shows good prognosis without any further metastasis and relapse. In addition, CCR7 trap therapy efficiently inhibits the lymphatic metastasis in a B16F10 melanoma mouse model, indicating its great potential for various metastatic diseases treatment.

ROS-Switchable Polymeric Nanoplatform with Stimuli-Responsive Release for Active Targeted Drug Delivery to Breast Cancer.

Tumor microenvironment plays a vital role in the process of tumor development, proliferation, invasion, and metastasis. It is well acknowledged that reduction in pH, reactive oxygen species (ROS), and increased level of glucose transporter 1 (GLUT1) have become featured intracellular and extracellular biochemical markers of cancer owing to oncogenic transformation and abnormal metabolism. To establish a distinctive drug delivery system directed against the tumor microenvironment features, we develop a newly engineered polymeric nanoplatform for efficient doxorubicin (DOX) delivery with reduced systemic toxicity and high antitumor efficiency. A thioketal cross-linker is used to improve the formulation's stability during circulation and to foster quick intracellular drug release in response to tumor's ROS potential. Furthermore, the low drug loading efficiency of conventional micelles is ameliorated in this polymeric nanoplatform via a drug-conjugation strategy with an acid-labile chemical bond. The optimized formulation, MPLs-sB-DOX micelles, possesses a high drug-loading efficiency (31%) within nanosize diameter (37.8 nm). In addition, this formulation shows significant improvement in the pharmacokinetics and biodistribution profiles with a 2.69-fold increase of tumor accumulation, while with largely reduced systemic toxicity in comparison with free DOX. With advantages of efficient cellular uptake, preferential tumor accumulation, and controlled release behaviors, MPLs-sB-DOX micelles demonstrate good tumor-targeting ability with reduced systemic toxicity, proving to be a promising formulation for breast cancer therapy.

ATP/pH Dual Responsive Nanoparticle with d-[des-Arg10 ]Kallidin Mediated Efficient In Vivo Targeting Drug Delivery.

Inflammation has been reported as one significant hallmark of breast cancer in relation to tumor development, metastasis, and invasion. The bradykinin receptor 1 (B1R) is highly expressed on inflammatory breast tumor cells thus providing a promising targeting site for tumor recognition and sufficient receptor mediated endocytosis. In this study, the authors evaluate the targeting efficiency of l-form and d-form [des-Arg10 ]kallidin both in vitro and in vivo. To further improve the drug delivery efficiency, the authors establish a dandelion like nanoparticle by combining the polymeric drug conjugates and aptamer complex together. The doxorubicin conjugated polymer is complexed with adenosine-5'-triphosphate (ATP) sensitive hybridized aptamer in self-assembly process by intercalating into the double strand scaffolds. The acid labile conjugating bond and ATP sensitive aptamer endow the nanoparticle with dual responsiveness to intracellular milieu, thus triggering a quick drug release in tumor cells. Remarkable therapeutic effects and tuned in vivo pharmacokinetics profiles are shown by the aptamer complexed drug conjugates nanoparticle with B1R active targeting modification. Therefore the strategies of B1R targeting and ATP/pH dual-responsiveness nanoparticle help achieve enhanced drug accumulation within tumor cells and efficient chemotherapy for breast cancer.

siRNA capsulated brain-targeted nanoparticles specifically knock down OATP2B1 in mice: a mechanism for acute morphine tolerance suppression.

Regulating main brain-uptake transporter of morphine may restrict its tolerance generation, then modify its antinociception. In this study, more than 2 fold higher intracellular uptake concentrations for morphine and morphine-6-glucuronide (M6G) were observed in stable expression cells, HEK293-hOATP2B1 than HEK293-MOCK. Specifically, the Km value of morphine to OATP2B1 (57.58 ± 8.90 µM) is 1.4-time more than that of M6G (80.31 ± 21.75 µM); Cyclosporine A (CsA), an inhibitor of OATP2B1, can inhibit their intracellular accumulations with IC50 = 3.90 ± 0.50 µM for morphine and IC50 = 6.04 ± 0.86 µM for M6G, respectively. To further investigate the role of OATP2B1 in morphine brain transport and tolerance, the novel nanoparticles of DGL-PEG/dermorphin capsulated siRNA (OATP2B1) were applied to deliver siRNA into mouse brain. Along with OATP2B1 depressed, a main reduction was found for each of morphine or M6G in cerebrums or epencephalons of acute morphine tolerance mice. Furthermore, calcium/calmodulin-dependent protein kinase IIα (CaMKIIα) in mouse prefrontal cortex (mPFC) underwent dephosphorylation at Thr286. In conclusion, OATP2B1 downregulation in mouse brain can suppress tolerance via blocking morphine and M6G brain transport. These findings might help to improve the pharmacological effects of morphine.

Amino Acid Metabolism Abnormity and Microenvironment Variation Mediated Targeting and Controlled Glioma Chemotherapy.

Energy metabolism abnormity is one of the most significant hallmarks of cancer. As a result, large amino acid transporter 1 (LAT1) is remarkably overexpressed in both blood-brain-barrier and glioma tumor cells, leading a rapid and sufficient substrate transportation. 3CDIT and 4CDIT are originally synthesized by modifying the existing most potent LAT1 substrate. 3CDIT is selected as its higher glioma-targeting ability. Since the microenvironment variation in tumor cells is another important feature of cancer, a great disparity in adenosine-5'-triphosphate (ATP) and glutathione (GSH) levels between extracellular and intracellular milieu can provide good possibilities for dual-responsive drug release in tumor cells. Doxorubicin (DOX) is successfully intercalated into the ATP aptamer DNA scaffolds, compressed by GSH-responsive polymer pOEI, and modified with 3CDIT to obtain 3CDIT-targeting pOEI/DOX/ATP aptamer nanoparticles (NPs). Enhanced NP accumulation and rapid GSH & ATP dual-responsive DOX release in glioma are demonstrated both in vitro and in vivo. More efficient therapeutic effects are shown with 3CDIT-targeting pOEI/DOX/ATP aptamer NPs than free DOX and no systemic toxicity is observed. Therefore, glioma-targeting delivery and GSH & ATP dual-responsive release guarantee an adequate DOX accumulation within tumor cells and ensure a safe and efficient chemotherapy for glioma.

T7 Peptide-Functionalized PEG-PLGA Micelles Loaded with Carmustine for Targeting Therapy of Glioma.

Glioma is regarded as the deadliest and most common brain tumor because of the extremely difficult surgical excision ascribed from its invasive nature. In addition, the natural blood-brain barrier (BBB) greatly restricts the therapeutics' penetration into the central nervous system. Carmustine (BCNU) is a widely used antiglioma drug in clinical applications. However, its serious complications prevent it from being applied in a clinical setting to some extent. Thus, it is urgent to explore novel BCNU delivery systems specially designed for glioma. Development of polymeric nanoparticles offers a favorable alternative to serve this purpose. Particularly, use of poly(lactic-co-glycolic acid) (PLGA) has been shown to be advantageous for its favorable biodegradability and biocompatibility, which ensure safe therapies. In this study, T7 peptide-conjugated, BCNU-loaded micelles were constructed successfully via the emulsion-solvent evaporation method. The micelles were characterized by transmission electron microscopy and dynamic light scattering in detail, and the capacity of BBB crossing was studied. The in vivo detecting results of the targeting effect using the BODIPY probe evidenced that T7-modified micelles showed a more pronounced accumulation and accumulated in the tumor more efficiently than in the unconjugated probe. Meanwhile, the targeting group exhibited the best curative effect accompanied with the lowest loss in body weight, the smallest tumor size, and an obviously prolonged survival time among the groups. In the near future, we believe the targeted delivery system specially designed for BCNU is expected to provide sufficient evidence to proceed to clinical trials.

Dual Functional Peptide-Driven Nanoparticles for Highly Efficient Glioma-Targeting and Drug Codelivery.

Compared with peripheral tumors, glioma is very difficult to treat, not only because it has general features of tumor but also because the therapy has been restricted by the brain-blood barrier (BBB). The two main features of tumor growth are angiogenesis and proliferation of tumor cells. RNA interference (RNAi) can downregulate VEGF overexpression to inhibit tumor neovascularization. Meanwhile, doxorubicin (DOX) has been used for cytotoxic chemotherapy to kill tumor cells. Thus, combining RNAi and chemotherapy has been regarded as a potential strategy for cancer treatment. However, the BBB limits the shVEGF-DOX codelivery system to direct into glioma. Here, a smart drug delivery system modified with a dual functional peptide was established, which could target to transferrin receptor (TfR) overexpressing on both the BBB and glioma. It showed that the dual-targeting delivery system had high tumor targeting efficiency in vitro and in vivo.

Brain-targeted co-delivery of therapeutic gene and peptide by multifunctional nanoparticles in Alzheimer's disease mice.

Multifunctional nanocarriers are increasingly promising for disease treatment aimed to regulate multiple pathological dysfunctions and overcome barriers in drug delivery. Here we develop a multifunctional nanocarrier for Alzheimer's disease (AD) treatment by achieving therapeutic gene and peptide co-delivery to brain based on PEGylated dendrigraft poly-l-lysines (DGLs) via systemic administration. The dendritic amine-rich structure of DGLs provides plenty reaction sites and positive charge for drug loading. Successful co-delivery of drugs overcoming the blood-brain barrier by brain-targeted ligand modification was demonstrated both in vitro and in vivo. The pharmacodynamics study of the system following multiple-dosing treatment was verified in transgenic AD mice. Down-regulation of the key enzyme in amyloid-ß formation was achieved by delivering non-coding RNA plasmid. Simultaneous delivery of the therapeutic peptide into brain leads to reduction of neurofibrillary tangles. Meanwhile, memory loss rescue in AD mice was also observed. Taken together, the multifunctional nanocarrier provides an excellent drug co-delivery platform for brain diseases.

Development of chitosan nanoparticles as drug delivery system for a prototype capsid inhibitor.

Oral delivery of biopharmaceutics drug disposition classification system (BDDCS) Class II or IV drugs with poor aqueous solubility and poor enzymatic and/or metabolic stability is very challenging. Bay41-4109, a member of the heteroaryldihydropyrimidine (HAP) family, inhibits HBV replication by destabilizing capsid assembly. It pertains to class II of the BDDCS which has a practically insoluble solubility which is 38 µg/mL (LYSA) and the oral delivery resulted in low bioavailability. The purpose of the current research work was to develop and evaluate Bay41-4109 loaded chitosan nanoparticles to increase the solubility and bioavailability for treatment of HBV. The Bay41-4109 nanoparticles were prepared by gelation of chitosan with tripolyphosphate (TPP) through ionic cross-linking. A three-factor three-level central composite design (CCD) was introduced to perform the experiments. A quadratic polynomial model was generated to predict and evaluate the independent variables with respect to the dependent variables. Bay41-4109 was encapsulated in the chitosan nanoparticles were demonstrated by PLM, FTIR, DSC, XRD and TEM etc. The in vivo results suggest that Bay41-4109 nanoparticles have better bioavailability and would be a promising approach for oral delivery of Bay41-4109 for the treatment of HBV.

Choline Derivate-Modified Doxorubicin Loaded Micelle for Glioma Therapy.

Ligand-mediated polymeric micelles have enormous potential for improving the efficacy of glioma therapy. Linear-dendritic drug-polymer conjugates composed of doxorubicin (DOX) and polyethylene glycol (PEG) were synthesized with or without modification of choline derivate (CD). The resulting MeO-PEG-DOX8 and CD-PEG-DOX8 could self-assemble into polymeric micelles with a nanosized diameter around 30 nm and a high drug loading content up to 40.6 and 32.3%, respectively. The optimized formulation 20% CD-PEG-DOX8 micelles had superior cellular uptake and antitumor activity against MeO-PEG-DOX8 micelles. The subcellular distribution using confocal study revealed that 20% CD-PEG-DOX8 micelles preferentially accumulated in the mitochondria. Pharmacokinetic study showed area under the plasma concentration-time curve (AUC0-t) and Cmax for 20% CD-PEG-DOX8 micelles and DOX solution were 1336.58 ± 179.43 mg/L·h, 96.35 ± 3.32 mg/L and 1.40 ± 0.19 mg/L·h, 1.15 ± 0.25 mg/L, respectively. Biodistribution study showed the DOX concentration of 20% CD-PEG-DOX8 micelles treated group at 48 h was 2.37-fold higher than that of MeO-PEG-DOX8 micelles treated group at 48 h and was 24 fold-higher than that of DOX solution treated group at 24 h. CD-PEG-DOX8 micelles (20%) were well tolerated with reduced cardiotoxicity, as evaluated in the body weight change and HE staining studies, while they induced most significant antitumor activity with longest media survival time in an orthotopic mouse model of U87-luci glioblastoma model as displayed in the bioluminescence imaging and survival curve studies. Our findings consequently indicated that 20% CD-PEG-DOX8 micelles are promising drug delivery system for glioma chemotherapy.