Iridoids rich fraction from Valeriana jatamansi Jones promotes axonal regeneration and motor functional recovery after spinal cord injury through activation of the PI3K/Akt signaling pathway.

Valeriana jatamansi Jones (VJJ), renowned for its extensive history in traditional Chinese medicine and ethnomedicine within China, is prevalently utilized to alleviate ailments such as epigastric distension and pain, gastrointestinal disturbances including food accumulation, diarrhea, and dysentery, as well as insomnia and other diseases. Moreover, the Iridoid-rich fraction derived from Valeriana jatamansi Jones (IRFV) has demonstrated efficacy in facilitating the recuperation of motor functions after spinal cord injury (SCI). This study is aimed to investigate the therapeutic effect of IRFV on SCI and its underlying mechanism. Initially, a rat model of SCI was developed to assess the impact of IRFV on axonal regeneration. Subsequently, employing the PC12 cell model of oxidative damage, the role and mechanism of IRFV in enhancing axonal regeneration were explored using the phosphoinositide-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway inhibitor LY294002. Ultimately, the same inhibitor was administered to SCI rats to confirm the molecular mechanism through which IRFV promotes axonal regeneration by activating the PI3K/Akt signaling pathway. The results showed that IRFV significantly enhanced motor function recovery, reduced pathological injury, and facilitated axonal regeneration in SCI rats. In vitro experiments revealed that IRFV improved PC12 cell viability, augmented axonal regeneration, and activated the PI3K/Akt signaling pathway. Notably, the inhibition of this pathway negated the therapeutic benefits of IRFV in SCI rats. In conclusion, IRFV promote promotes axonal regeneration and recovery of motor function after SCI through activation of the PI3K/Akt signaling pathway.

Effects of a lower limb walking exoskeleton on quality of life and activities of daily living in patients with complete spinal cord injury: A randomized controlled trial.

BACKGROUND: In recent years, lower limb walking exoskeletons have been widely used in the study of spinal cord injury (SCI). OBJECTIVE: To explore the effect of a lower limb walking exoskeleton on quality of life and functional independence in patients with motor complete SCI. METHODS: This was a multi-center, single blind, randomized controlled trial. A total of 16 SCI patients were randomly assigned to either the exoskeleton-assisted walking (EAW) group (n= 8) or the conventional group (n= 8). Both groups received conventional rehabilitation training, including aerobic exercise and strength training. The EAW group additionally conducted the exoskeleton-assisted walking training using an AIDER powered robotic exoskeleton for 40-50 minutes, 5 times/week for 8 weeks. World Health Organization quality of life-BREF (WHOQOL-BREF) and the Spinal Cord Independence Measure III (SCIM-III) were used for assessment before and after training. RESULTS: There was an increasing tendency of scores in the psychological health, physical health, and social relationships domain of WHOQOL-BREF in the EAW group after the intervention compared with the pre-intervention period, but there was no significant difference (P> 0.05). SCIM-III scores increased in both groups compared to pre-training, with only the conventional group showing a significant difference after 8 weeks of training (P< 0.05). CONCLUSION: A lower limb walking exoskeleton may have potential benefits for quality of life and activities of daily living in patients with motor complete SCI.

Selenium Nanoparticles Stabilized by ß-Glucan Nanotubes from Black Fungus and Their Effects on the Proliferation, Apoptosis, and Cell Cycle of HepG2 Cells.

Selenium nanoparticles (Se NPs) have significant anticancer effects, but their poor water solubility and dispersibility limit their further applications in biomedical fields. Biomacromolecules have often been used as dispersants or stabilizers in synthesized Se NPs because they can enhance the dispersibility of Se NPs and reduce their side effects. Our previous studies reported a triple-helix ß-glucan (BFP) from the fruiting bodies of black fungus, which showed a good self-assembly ability in constructing hollow nanotubes for loading metal nanoparticles. Therefore, in the present work, BFP nanotubes were designed as carriers to entrap large amounts of Se NPs in order to enhance their stability and anticancer effects. The results showed that Se NPs were successfully synthesized and loaded inside the BFP nanotubes, and the composite (BFP-Se) exhibited high stability and dispersibility due to the covalent Se-O bonds between the Se NPs and the hydroxyl groups on the BFP nanotubes. Moreover, BFP-Se showed significant effects on the proliferation, apoptosis, and cell cycle of HepG2 cells compared to those exhibited by Se NPs. The mechanism was associated with BFP, which acted as a dispersant or stabilizer, resulting in the enhanced cellular uptake of the Se NPs. BFP also activated the death receptor-mediated and mitochondria-mediated apoptotic pathways in HepG2 cells. These results suggest that BFP-Se has potential applications in biomedical fields, especially for the treatment of human liver cancers.

Mechanism of Valeriana Jatamansi Jones for the treatment of spinal cord injury based on network pharmacology and molecular docking.

Spinal cord injury (SCI) is characterized by high rates of disability and death. Valeriana jatamansi Jones (VJJ), a Chinese herbal medicine, has been identified to improve motor function recovery in rats with SCI. The study aimed to analyze the potential molecular mechanisms of action of VJJ in the treatment of SCI. The main ingredients of VJJ were obtained from the literature and the SwissADME platform was used to screen the active ingredients. The Swiss TargetPrediction platform was used to predict the targets of VJJ, and the targets of SCI were obtained from the GeneCards and OMIM databases. The intersecting genes were considered potential targets of VJJ in SCI. The protein-protein interaction network was constructed using the STRING database and the hub genes of VJJ for SCI treatment were screened according to their degree values. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed using the Metascape database. Cytoscape software was used to construct the "herb-ingredient-target-pathway" network. Preliminary validation was performed using molecular docking via Auto Dock Vina software. A total of 56 active ingredients of VJJ, mainly iridoids, were identified. There were 1493 GO items (P < .01) and 173 signaling pathways (P < .01) obtained from GO and Kyoto Encyclopedia of Genes and Genomes enrichment, including the phosphoinositide-3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, hypoxia-inducible factor 1 signaling pathway, and tumor necrosis factor signaling pathway. Molecular docking revealed that 12 hub genes enriched in the PI3K/Akt signaling pathway had a high binding affinity for the active ingredient of VJJ. VJJ may exert its therapeutic effects on SCI through the iridoid fraction, acting on signal transducer and activator of transcription 3, CASP3, AKT1, tumor necrosis factor, mammalian target of rapamycin, interleukin 6, and other hub genes, which may be related to the PI3K/Akt signaling pathway.

Cascade strategy for glucose oxidase-based synergistic cancer therapy using nanomaterials.

Nanomaterial-based cancer therapy faces significant limitations due to the complex nature of the tumor microenvironment (TME). Starvation therapy is an emerging therapeutic approach that targets tumor cell metabolism using glucose oxidase (GOx). Importantly, it can provide a material or environmental foundation for other diverse therapeutic methods by manipulating the properties of the TME, such as acidity, hydrogen peroxide (H2O2) levels, and hypoxia degree. In recent years, this cascade strategy has been extensively applied in nanoplatforms for ongoing synergetic therapy and still holds undeniable potential. However, only a few review articles comprehensively elucidate the rational designs of nanoplatforms for synergetic therapeutic regimens revolving around the conception of the cascade strategy. Therefore, this review focuses on innovative cascade strategies for GOx-based synergetic therapy from representative paradigms to state-of-the-art reports to provide an instructive, comprehensive, and insightful reference for readers. Thereafter, we discuss the remaining challenges and offer a critical perspective on the further advancement of GOx-facilitated cancer treatment toward clinical translation.

The extraction, structure characterization and hydrogel construction of a water-insoluble ß-glucan from Poria cocos.

Most reported polysaccharides from Poria cocos (PCPs) in traditional Chinese medicine decoctions were water-soluble heteropolysaccharides while the water-insoluble PCPs were scarcely researched due to the poor water-solubility. In this study, a water-insoluble polysaccharide with high yield of 59%, and high purity with a glucan content of 98.8%, was isolated by diluted sodium hydroxide at low temperature and coded as PCPA. The chemical structure of PCPA was identified as a liner ß-glucan with 1, 3-linked glycosidic bond by the fourier infrared spectrum (FT-IR), ion chromatography (ICP), gas chromatography and mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) measurements. Importantly, PCPA was successfully used to construct hydrogels (PCPA-Gs) with good thermal stability, water retention ability and swelling property through simple physical cross-linking, due to the abundance of hydroxyl groups on glucan chains. Moreover, the rheology analysis of PCPA-Gs showed a rapid transition between gel and sol as well as the shear-thinning property. The hydrogel developed in this study holds promise for applications in the food, pharmaceutical, and cosmetic fields.

Anticonvulsive Effect of Glucosyl Xanthone Mangiferin on Pentylenetetrazol (PTZ)-Induced Seizure-Provoked Mice.

Anxiety and depression are major side effects induced by currently available antiepileptic drugs; apart from this, they also diminish intelligence and language skills which cause hepatic failure, anemia, etc. Hence, in this study, we assessed antiepileptic effect of a phytochemical mangiferin. Epilepsy, a prevalent non communicable neurological disorder, affects infants and older population throughout the world. Epilepsy-induced comorbidities are more severe and if not treated cautiously lead to disability and even worse cases, mortality. The onset and duration of convulsion were observed. Seizure severity score was assessed by provoking kindling with 35 mg/kg PTZ. Prooxidants and antioxidants were measured to assess the antioxidant effect of mangiferin. Inflammatory markers were measured to determine the anti-inflammatory effect of mangiferin. The levels of neurotransmitters and ATPases were quantified to evaluate the neuroprotective effect of mangiferin. Mangiferin significantly decreased the onset and duration convulsion. It also decreased the seizure severity score, locomotor activity, and immobilization effectively. The excitatory neurotransmitter was reduced, and inhibitory neurotransmitter was increased in mice treated with mangiferin. Overall, our results confirm that mangiferin efficiently protects mice from PTZ-induced seizures. It can be subjected to further research to be prescribed as a potent antiepileptic drug.

Synthesis, Biological Evaluation and Action Mechanism Study of New Mitochondria-Targeted Curcumin Derivative as Potential Antitumor Drugs.

Mitochondria have emerged as important targets in cancer therapy due to their key role in regulating energy supply, maintaining redox homeostasis, and intrinsic apoptosis. Curcumin (CUR) has shown promise in inhibiting the proliferation and metastasis of cancer cells by inducing apoptosis and arresting cell cycle. However, the clinical application of CUR has been limited by its low stability and poor tumor selectivity. To address these issues, the novel mitochondria-targeted curcumin derivatives were synthesized through the unilateral coupling (CUR-T) or bilateral coupling (CUR-2T) of curcumin's phenolic hydroxy groups with triphenyl phosphorus via ester bond. The aim was to achieve better stability, higher tumor selectivity, and stronger curative efficacy. The results of stability and biological experiments indicated that both stability and cytotoxicity were arranged in descending order of CUR-2T>CUR-T>CUR. In ovarian cancer cells (A2780 cells), CUR-2T showed well-defined preferential selectivity towards cancer cells and exhibited efficient anticancer efficacy due to its superior mitochondria accumulation ability. Subsequently, the mitochondrial redox balance was disrupted, accompanied by increased ROS levels, decreased ATP levels, dissipated MMP, and increased G0 /G1 phase arrest, leading to a higher apoptotic rate. In summary, the results of this study suggest that CUR-2T holds substantial promise for further development as a potential agent for the treatment of ovarian cancer.

Formulation and evaluation of a two-stage targeted liposome coated with hyaluronic acid for improving lung cancer chemotherapy and overcoming multidrug resistance.

Multidrug resistance (MDR) has emerged as a prominent challenge contributing to the ineffectiveness of chemotherapy in treating non-small cell lung cancer (NSCLC) patients. Currently, mitochondria of cancer cells are identified as a promising target for overcoming MDR due to their crucial role in intrinsic apoptosis pathway and energy supply centers. Here, a two-stage targeted liposome (HA/TT LP/PTX) was successfully developed via a two-step process: PTX-loaded cationic liposome (TT LP/PTX) were formulated by lipid film hydration & ultrasound technique, followed by further coating with natural anionic polysaccharide hyaluronic acid (HA). TT, an amphipathic polymer conjugate of triphenylphosphine (TPP)-tocopheryl polyethylene glycol succinate (TPGS), was used to modify the liposomes for mitochondrial targeting. The average particle size, zeta potential and encapsulation efficiency (EE%) of HA/TT LP/PTX were found to be 153 nm, -30.3 mV and 92.1% based on the optimal prescription of HA/TT LP/PTX. Compared to cationic liposome, HA-coated liposomes showed improved stability and safety, including biological stability in serum, cytocompatibility, and lower hemolysis percentage. In drug-resistant A549/T cells, HA was shown to improve the cellular uptake of PTX through CD44 receptor-mediated endocytosis and subsequent degradation by hyaluronidase (HAase) in endosomes. Following this, the exposure of TT polymer facilitated the accumulation of PTX within the mitochondria. As a result, the function of mitochondria in A549/T cells was disturbed, leading to an increased ROS level, decreased ATP level, dissipated MMP, and increased G2/M phase arrest. This resulted in a higher apoptotic rate and stronger anticancer efficacy.

Prevalence and risk factors of covert hepatic encephalopathy in cirrhotic patients: A multicenter study in China.

OBJECTIVE: We aimed to investigate the prevalence of covert hepatic encephalopathy (CHE) in cirrhotic patients in China and its risk factors. METHODS: A multicenter prospective observational study was conducted from January 2021 to March 2022 at 16 medical centers across China to investigate the risk factors of CHE and establish a prediction model for CHE episodes. RESULTS: A total of 528 patients were enrolled in the study. Based on both the psychometric hepatic encephalopathy score and Stroop test results, the prevalence of CHE was 50.4% (266/528), and the consistency between these two tests was 68.9%. Multivariate analysis showed that age (odds ratio [OR] 1.043, 95% confidence interval [CI] 1.022-1.063, P < 0.001), duration of education (OR 0.891, 95% CI 0.832-0.954, P = 0.001), comorbidities of cardiovascular diseases, hypertension, cerebral apoplexy or diabetes mellitus (OR 2.072, 95% CI 1.370-3.133, P < 0.001), Child-Pugh score (OR 1.142, 95% CI 1.029-1.465, P = 0.025), and blood urea nitrogen concentration (OR 1.126, 95% CI 1.038-1.221, P = 0.004) were associated with CHE episodes. According to the Chronic Liver Disease Questionnaire, CHE patients had lower scores for abdominal symptoms and systemic symptoms (P < 0.001), indicating a poor health-related quality of life. Based on a stepwise Cox regression hazard model, we established a nomogram for determining the probabilities of CHE episodes, and the area under the receiver operating characteristic curve was 0.733 (95% CI 0.679-0.788) and 0.713 (95% CI 0.628-0.797) in the training and validation cohorts. CONCLUSIONS: CHE is a common complication of cirrhosis in China. Large-scale studies with long-term follow-up are needed to determine the natural history of Chinese CHE patients.

The signaling protein GIV/Girdin mediates the Nephrin-dependent insulin secretion of pancreatic islet ß cells in response to high glucose.

Glucose-stimulated insulin secretion of pancreatic ß cells is essential in maintaining glucose homeostasis. Recent evidence suggests that the Nephrin-mediated intercellular junction between ß cells is implicated in the regulation of insulin secretion. However, the underlying mechanisms are only partially characterized. Herein we report that GIV is a signaling mediator coordinating glucose-stimulated Nephrin phosphorylation and endocytosis with insulin secretion. We demonstrate that GIV is expressed in mouse islets and cultured ß cells. The loss of function study suggests that GIV is essential for the second phase of glucose-stimulated insulin secretion. Next, we demonstrate that GIV mediates the high glucose-stimulated tyrosine phosphorylation of GIV and Nephrin by recruiting Src kinase, which leads to the endocytosis of Nephrin. Subsequently, the glucose-induced GIV/Nephrin/Src signaling events trigger downstream Akt phosphorylation, which activates Rac1-mediated cytoskeleton reorganization, allowing insulin secretory granules to access the plasma membrane for the second-phase secretion. Finally, we found that GIV is downregulated in the islets isolated from diabetic mice, and rescue of GIV ameliorates the ß-cell dysfunction to restore the glucose-stimulated insulin secretion. We conclude that the GIV/Nephrin/Akt signaling axis is vital to regulate glucose-stimulated insulin secretion. This mechanism might be further targeted for therapeutic intervention of diabetic mellitus.

Preparation and evaluation of stingray skin collagen/oyster osteoinductive composite scaffolds.

The regeneration of bone defects is a major challenge for clinical orthopaedics. Herein, we designed and prepared a new type of bioactive material, using stingray skin collagen and oyster shell powder (OSP) as raw materials. A stingray skin collagen/oyster osteoinductive composite scaffold (Col-OSP) was prepared for the first time by genipin cross-linking, pore-forming and freeze-drying methods. These scaffolds were characterized by ATR-FTIR, SEM, compression, swelling, cell proliferation, cell adhesion, alkaline phosphatase activity, alizarin red staining and RT-PCR etc. The Col-OSP scaffold had an interconnected three-dimensional porous structure, and the mechanical properties of the Col-OSP composite scaffold were enhanced compared with Col, combining with the appropriate swelling rate and degradation rate, the scaffold was more in line with the requirements of bone tissue engineering scaffolds. The Col-OSP scaffold was non-toxic, promoted the proliferation, adhesion, and differentiation of MC3T3-E1 cells, and stimulated the osteogenesis-related genes expressions of osteocalcin (OCN), collagen type I (COL-I) and RUNX2 of MC3T3-E1 cells.

In-situ formable dextran/chitosan-based hydrogels functionalized with collagen and EGF for diabetic wounds healing.

Delayed or non-healing skin wounds causing gangrene or even amputation, greatly threats diabetic patients lives. Herein, a bioactive, in-situ formable hydrogel based wound dressing was designed through simple Schiff base reaction. Oxidized dextran (OD) and carboxyethyl chitosan (CEC) were crosslinked together and applied as the main porous framework of hydrogel. To improve the mechanical strength and biocompatibility, collagen (Col) and EGF (Epidermal Growth Factor) were introduced into OD-CEC precursors: (1) after addition of only Col, the mechanical strength of hydrogels was improved by participating the functional -NH2 group of Col into the crosslinking process. Moreover, swelling ratio was as high as 750% on 3%OD-3%CEC-Col (water retention rate was 65 wt% after 7 days). (2) Once we introduced both Col and EGF into the OD-CEC hydrogel, the proliferation of mouse embryonic fibroblast (NIH 3T3) cells was promoted using 3%OD-3%CEC-Col/EGF, an accelerated wound healing was observed with 86% wound closure after only 14 operative days. Hematoxylin and eosin (H&E) staining and Masson staining indicated the synergy of Col and EGF might promote new tissue's formation, well collagen distributions and thus accelerate skin regeneration, presenting great potentials in wound healing of diabetic patients.

Uniform and disperse selenium nanoparticles stabilized by inulin fructans from Codonopsis pilosula and their anti-hepatoma activities.

The present work reported the extraction, purification and characterization of an inulin fructan from Codonopsis pilosula (CPW1) and its application in stabilization of selenium nanoparticles (SeNPs). The morphology, stability, and stabilization mechanism of CPW1 stabilized SeNPs (CPW1-Se) were explored, and the results showed that the SeNPs were amorphous state, with size of 54-79 nm, and kept stable within 15 days due to the interaction between SeNPs and the hydroxyl groups on the surface of CPW1. Moreover, the effects on proliferation and apoptosis of CPW1-Se to both normal cells (293T) and liver cancer cells (Huh-7 and HepG2) were evaluated systematically by using the CCK8 assay, plate clone formation assay, flow cytometry and western blot. The results indicated that CPW1-Se possessed selective anti-hepatoma activities without side effects on normal cells, which exhibited strong potential application in liver cancer treatments.

Pharmacokinetic and tissue distribution study of eight volatile constituents in rats orally administrated with the essential oil of Artemisiae argyi Folium by GC-MS/MS.

Artemisia argyi is commonly used as a remedy for gynecological and respiratory disease in traditional Chinese medicine. The essential oil is considered as the major active ingredients of A. argyi, mainly composed of eucalyptol, α-thujone, camphor, borneol, bornyl acetate, eugenol, ß-caryophyllene, and caryophyllene oxide, while limited study addresses the in vivo disposition of these volatile ingredients. In present study, a rapid, sensitive and selective GC-MS/MS method has been developed and validated for the quantification of the eight volatile constituents in rat plasma and tissues after orally dosing with the essential oil of Artemisiae Argyi Folium (AAEO) using naphthalene as an internal standard (IS). The analytes were extracted from biosamples by liquid-liquid extraction with hexane/ethyl acetate. The GC separation was achieved on a TG-5SILMS column (30 m × 0.25 mm, 0.25 µm film thickness) and MS detection was performed on selective reaction monitoring (SRM) mode. The assay had a lower limit of quantification (LLOQ) less than 2 ng/ml for the analytes with good linearity (r ≥ 0.9907). Their disposition profile in rat plasma and tissues was characterized after orally giving AAEO, and the data revealed the analytes underwent rapid absorption from GI tract and were mainly transferred to the liver, heart, kidney, lung, and spleen with prompt elimination. The results provided a meaningful basis for guiding the pharmacodynamic study and clinical applications of this herbal medicine.

Hyaluronic Acid-Functionalized Hollow Mesoporous Silica Nanoparticles as pH-Sensitive Nanocarriers for Cancer Chemo-Photodynamic Therapy.

Hollow mesoporous silica nanoparticles (HMSNs) served as nanocarriers for transporting doxorubicin hydrochloride (DOX) and indocyanine green (ICG) and were incorporated into a pH-sensitive targeted drug delivery system (DDS). Boronate ester bonds were employed to link HMSNs and dopamine-modified hyaluronic acid (DA-HA), which acted as both the "gatekeeper" and targeting agents (HMSNs-B-HA). Well-dispersed HMSNs-B-HA with a diameter of about 170 nm was successfully constructed. The conclusion was drawn from the in vitro drug release experiment that ICG and DOX (ID) co-loaded nanoparticles (ID@HMSNs-B-HA) with high drug loading efficiency could sustain drug release under acidic conditions. More importantly, in vitro cell experiments perfectly showed that ID@HMSNs-B-HA could well inhibit murine mammary carcinoma (4T1) cells via chemotherapy combined with photodynamic therapy and accurately target 4 T1 cells. In summary, all test results sufficiently demonstrated that the prepared ID@HMSNs-B-HA was a promising nano-DDS for cancer photodynamic combined with chemotherapy.

Extraction, characterization and anti-inflammatory activities of an inulin-type fructan from Codonopsis pilosula.

A homogenous polysaccharide from Codonopsis pilosula (CPP) was isolated and identified to be an inulin-type fructan, coded as CPP1-2-1. The polysaccharide exhibited anti-inflammatory effect against lipopolysaccharide (LPS) induced RAW264.7 cells in vitro and dextran sodium sulfate (DSS)-induced colitis mice in vivo. Moreover, the expression of cytokines was further detected by qPCR, and the results showed that the polysaccharides can reduce the expression of inflammatory factors such as TLR4, NF-κB, TNF-α and IL-6 in the cells, indicating the anti-inflammatory activities may be achieved by inhibiting the activation of TLR4/NF-κB pathway.

Hyaluronic acid targeted and pH-responsive nanocarriers based on hollow mesoporous silica nanoparticles for chemo-photodynamic combination therapy.

In this work, a pH-responsive and tumor targeted multifunctional drug delivery system (RB-DOX@HMSNs-N = C-HA) was designed to realize chemo-photodynamic combination therapy. Hollow mesoporous silica nanoparticles (HMSNs) was served as the host material to encapsulate doxorubicin (DOX) and photosensitizer rose bengal (RB). Hyaluronic acid (HA) was modified on the surface of HMSNs via pH-sensitive Schiff base bonds as gatekeeper as well as targeted agent. Characterization results indicated the successful preparation of HMSNs-N = C-HA with appropriate diameter of 170 nm around and the nanocarriers displayed superior drug loading capacity (15.30 % for DOX and 12.78 % for RB). Notably, the results of in vitro drug release experiments confirmed that the system possessed good pH-sensitivity, which made it possible to release cargoes in slight acid tumor micro-environments. Significantly, the in vitro cell uptake and cytotoxicity assay results fully proved that RB-DOX@HMSNs-N = C-HA could precisely target murine mammary carcinoma (4T1) cells and effectively inhibit tumor cells viability with chemo-photodynamic synergistic therapy. Overall, our work (RB-DOX@HMSNs-N = C-HA) provides an efficient approach for the development of chemo-photodynamic combination therapy.

Modulation of cyclic topology toward enhanced drug delivery, from linear and tadpole-like to dumbbell-shaped copolymers.

In this study, an efficient strategy for the synthesis of dumbbell-shaped amphiphilic copolymers with cyclic moieties as the two bells was developed and the enhanced performance of dumbbell-shaped copolymers for controlled drug release because of the simultaneous introduction of two macrocycles was disclosed.

Polydopamine coated hollow mesoporous silica nanoparticles as pH-sensitive nanocarriers for overcoming multidrug resistance.

A nanocarrier system of methoxypolyethylene glycol amine (mPEG-NH2) functionalized polydopamine (PDA) coated hollow mesoporous silica nanoparticles (HMSNs-PDA-PEG) was developed with pH-responsive, which combined doxorubicin hydrochloride (DOX) and quercetin (QUR) to reverse multidrug resistance (MDR) and improved anticancer effects on taxol (TAX) and DOX double resistant human colorectal cancer cell line HCT-8 (HCT-8/TAX cells). Well-dispersed nanoparticles (HMSNs-PDA-PEG) were prepared with a dimension of around 170 nm. The surface morphology and chemical properties of HMSNs-PDA-PEG were also successfully characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, Fourier transform infrared spectroscopy (FT-IR) and dynamic light scattering (DLS). Drug release experiments results indicated that DOX and QUR (QD) loaded nanoparticles (HMSNs-PDA-PEG@QD) had similar release kinetic profiles of each drug, which all exhibited highly sensitive to pH value due to the surface PDA coating. Additionally, the HCT-8 cells or HCT-8/TAX cells were employed to assess the cellular uptake and cytotoxicity of various drug-free or drug-loaded HMSNs samples. Meanwhile, a series of biological evaluations demonstrated that the HMSNs-PDA-PEG@QD exhibited remarkable ability to overcome MDR compared with free DOX and HMSNs-PDA-PEG@DOX. Taken together, these results revealed that HMSNs-PDA-PEG@QD was suitable as a prospective and efficient drug delivery nanosystem for overcoming multidrug resistance.