Engineered Macrophage Membrane-Coated Nanoparticles with Enhanced CCR2 Expression Promote Spinal Cord Injury Repair by Suppressing Neuroinflammation and Neuronal death.

Spinal cord injury (SCI) is a severe neurological disorder characterized by significant disability and limited treatment options. Mitigating the secondary inflammatory response following the initial injury is the primary focus of current research in the treatment of SCI. CCL2 (C─C motif chemokine ligand 2) serves as the primary regulator responsible for inflammatory chemotaxis of the majority of peripheral immune cells, blocking the CCL2-CCR2 (C─C chemokine receptor type 2) axis has shown considerable therapeutic potential for inflammatory diseases, including SCI. In this study, it presents a multifunctional biomimetic nanoplatform (CCR2-MM@PLGA/Cur) specifically designed to target the CCL2-CCR2 axis, which consisted of an engineered macrophage membrane (MM) coating with enhanced CCR2 expression and a PLGA (poly (lactic-co-glycolic acid)) nanoparticle that encapsulated therapeutic drugs. CCR2 overexpression on MM not only enhanced drug-targeted delivery to the injury site, but also attenuated macrophage infiltration, microglia pro-inflammatory polarization, and neuronal apoptosis by trapping CCL2. Consequently, it facilitated neural regeneration and motor function recovery in SCI mice, enabling a comprehensive treatment approach for SCI. The feasibility and efficacy of this platform are confirmed through a series of in vitro and in vivo assays, offering new insights and potential avenues for further exploration in the treatment of SCI.

Oncological outcomes of conversion therapy in gastric cancer patients with peritoneal metastasis: a large-scale retrospective cohort study.

BACKGROUND: Data on the long-term oncological outcomes of patients who undergo conversion surgery (CS) in gastric cancer (GC) patients with peritoneal metastasis (PM) are limited. METHODS: GC patients with PM who received intraperitoneal (ip) and systemic chemotherapy between April 2015 and January 2021 were enrolled. Multivariate analysis was performed to identify risk factors associated with survival. Clinicopathological and survival outcomes were compared between those with CS and those without CS (NCS). The paclitaxel (PTX) plus tegafur-gimeracil-oteracil potassium capsules (S-1) (PS) + ip PTX and oxaliplatin plus S-1 (SOX) + ip PTX groups were matched in a 1:1 ratio using propensity score matching. Oncological and survival data were collected and analyzed. RESULTS: A total of 540 patients who received ip chemotherapy via subcutaneous port and systemic chemotherapy were analyzed and 268 patients were enrolled, including 113 who underwent CS and 155 who did not. Overall survival (OS) were 27.0 months and 11.8 months in the CS and NCS groups (P < 0.0001), respectively. R0 resection was an independent prognostic factor for patients who underwent CS. The OS of patients with or without ovariectomy was 21.3 or 12.0 months (P < 0.0001). No difference of clinicopathological and survival outcomes was found between the PS + ip PTX and SOX + ip PTX groups. CONCLUSION: Conversion therapy is safe and adverse events were manageable. CS improves the survival of GC patients with PM after ip and systemic chemotherapy. R0 is an important prognostic factor. Furthermore, outcomes are comparable between the PS + ip PTX and SOX + ip PTX groups.

Purification of triterpenoid saponins and 25R/25S-inokosterone from Achyranthes bidentata Bl. by high-speed countercurrent chromatography coupled silver nitrate coordination.

An effective method by high-speed countercurrent chromatography coordinated with silver nitrate for the preparative separation of sterones and triterpenoid saponins from Achyranthes bidentata Blume was developed. Methyl tert-butyl ether/n-butanol/acetonitrile/water (4:2:3:8, v/v/v/v) was selected for 20-hydroxyecdysone (compound 1), chikusetsusaponin IVa methyl ester (compound 4), 2'-glycan-11-keto-pigmented saponin V (compound 5), as well as a pair of isomers of 25S-inokosterone (compound 2) and 25R-inokosterone (compound 3), which were further purified by silver nitrate coordinated high-speed countercurrent chromatography. What is more, dichloromethane/methanol/isopropanol/water (6:6:1:4, v/v/v/v) was applied for calenduloside E (compound 6), 3ß-[(O-ß-d-glucuronopyranosyl)-oxy]-oleana-11,13-dien-28-oic acid (compound 7), zingibroside R1 (compound 8) and chikusetsusaponin IVa (compound 9). Adding Ag+ to the solvent system resulted in unique selectivity for 25R/25S isomers of inokosterone, which increased the complexing capability and stability of Ag+ coordinated 25S-inokosterone, as well as the α value between them. These results were further confirmed by the computational calculation of geometry optimization and frontier molecular orbitals assay. Comprehensive mass spectrometry and nuclear magnetic resonance analysis demonstrated the structures of the obtained compounds.

Efficient discovery of active isolates from Dioscorea spongiosa by the combination of bioassay-guided macroporous resin column chromatography and high-speed counter-current chromatography.

In the present study, twelve compounds from Dioscorea spongiosa were successfully purified by an efficient technique combined bioassay-guided fractionation macroporous resin column chromatography (MRCC) pretreatment and high-speed counter-current chromatography (HSCCC) separation for the first time. Then, D101 MRCC was used to fractionate the crude extract into five parts, which further applied the bioassay-guided fractionation strategy to screen the active fractions of 2 and 4. As for the separation, 200 mg Fr.2 was purified by HSCCC using EtOAc/n-BuOH/H2 O (2:2:3, v/v), leading to annulatomarin (1), dioscoresides C (2), diosniponol C (3), methyl protodioscin (4), pseudoprotodioscin (5), protogracillin (6), as well as 200 mg Fr.4 yielding montroumarin (7), dioscorone A (8), diosniponol D (9), protodioscin (10), gracillin (11), and dioscin (12) using CH2 Cl2 /MeOH/H2 O (3:3:2, v/v) with the purities over 95.0%. Finally, the isolates were assayed for their anti-inflammatory, urico-lowering, and anti-diabetic activities in vitro, which indicated that the steroidal saponins of 5, 6, and 11 showed all these three activities.

The C2 isthmus screw provided sufficient biomechanical stability in the setting of atlantoaxial dislocation-a finite element study.

BACKGROUND: The emerging of the C2 isthmus screw fixation technique is gaining popularity in the setting of atlantoaxial dislocation or other conditions requiring fixation of C2. However, the biomechanical stability of this fixation is poorly understood. PURPOSE: To compare and elucidate the biomechanical stability of C2 pedicle screw (C2PS), C2 isthmus screw (C2IS) and C2 short isthmus screw (C2SIS) fixation techniques in atlantoaxial dislocation (AAD). METHOD: A three-dimensional finite element model (FEM) from occiput to C3 was established and validated from a healthy male volunteer. Three FEMs, C1 pedicle screw (PS)-C2PS, C1PS-C2IS, C1PS-C2SIS were also constructed. The range of motion (ROM) and the maximum von Mises stress under flexion, extension, lateral bending and axial rotation loading were analyzed and compared. The pullout strength of the three fixations for C2 was also evaluated. RESULT: C1PS-C2IS model showed the greatest decrease in ROM with flexion, extension, lateral bending and axial rotation. C1PS-C2PS model showed the least ROM reduction under all loading conditions than both C2IS and C2SIS. The C1PS-C2PS model had the largest von Mises stress on the screw under all directions followed by C1PS-C2SIS, and lastly the C1PS-C2IS. Under axial rotation and lateral bending loading, the three models showed the maximum and minimum von Mises stress on the screw respectively. The stress of the three models was mainly located in the connection of the screw and rod. Overall, the maximum screw pullout strength for C2PS, C2IS and C2SIS were 729.41N, 816.62N, 640.54N respectively. CONCLUSION: In patients with atlantoaxial dislocations, the C2IS fixation provided comparable stability, with no significant stress concentration. Furthermore, the C2IS had sufficient pullout strength when compared with C2PS and C2SIS. C2 isthmus screw fixation may be a biomechanically favourable option in cases with AAD. However, future clinical trials are necessary for the evaluation of the clinical outcomes of this technique.

Biomedical Applications of Sulfonylcalix[4]arene-Based Metal-Organic Supercontainers.

Coordination cages sustained by metal-ligand interactions feature polyhedral architectures and well-defined hollow structures, which have attracted significant attention in recent years due to a variety of structure-guided promising applications. Sulfonylcalix[4]arenes-based coordination cages, termed metal-organic supercontainers (MOSCs), that possess unique multi-pore architectures containing an endo cavity and multiple exo cavities, are emerging as a new family of coordination cages. The well-defined built-in multiple binding domains of MOSCs allow the efficient encapsulation of guest molecules, especially for drug delivery. Here, we critically discuss the design strategy, and, most importantly, the recent advances in research surrounding cavity-specified host-guest chemistry and biomedical applications of MOSCs.

[A new sesquiterpenoid from Lindera aggregata].

The chemical composition of the aqueous part of the extract from Lindera aggregata was studied, which was separated and purified by the macroporous resin column chromatography, MCI medium pressure column chromatography, semi-preparative high-performance liquid phase and other methods. The structures of the compounds were identified according to physical and chemical properties and spectroscopic data. Thirteen compounds were isolated and identified from the aqueous extracts, which were identified as(1S,3R,5R,6R,8S,10S)-epi-lindenanolide H(1), tachioside(2), lindenanolide H(3), leonuriside A(4), 3,4-dihydroxyphenyl ethyl ß-D-glucopyranoside(5), 3,4,5-trimethoxyphenol-1-O-6-α-L-rhamnose-(1→6)-O-ß-D-glucoside(6), 5-hydroxymethylfurfural(7),(+)-lyoniresin-4-yl-ß-D-glucopyranoside(8), lyoniside(9), norboldine(10), norisopordine(11), boldine(12), reticuline(13). Among them, compound 1 was a new one, and compounds 2, 5, 6, 8, 9 were obtained from L. aggregata for the first time. The inflammatory model was induced by lipopolysaccharide(LPS) in the RAW264.7 cells. The results showed that compounds 1, 8, 10 and 12 had significant anti-inflammatory activity.

Insights into the Anticorrosion Performance of Solanum lyratum Leaf Extract for Copper in Sulfuric Acid Medium.

In this paper, Solanum lyratum leaves were prepared into a corrosion inhibitor by a pure water extraction method. As a natural plant, S. lyratum leaf extract as a corrosion inhibitor has green features. S. lyratum leaf extract (SLLE) can effectively inhibit the corrosion of Cu in H2SO4 solution. The protective effect on copper in 0.5 mol/L H2SO4 solution was studied by electrochemical measurement, Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and theoretical calculation. These results showed that the maximum corrosion inhibition efficiency (η) of SLLE for copper obtained in the electrochemical measurement at different temperatures is more than 90%. The adsorption of SLLE on copper surfaces conforms to the Langmuir isotherm adsorption model. FTIR and XPS showed the bonding information. SEM and AFM proved that the SLLE can protect the copper from corrosion media. The interaction and inhibition mechanism between the SLLE and copper surface was further revealed at the molecular level by theoretical calculation.

Sintilimab combined neoadjuvant intraperitoneal and systemic chemotherapy in gastric cancer with peritoneal metastasis.

Intraperitoneal chemotherapy combined with systemic chemotherapy is one of the therapeutic modalities currently used for the treatment of gastric cancer patients with peritoneal metastasis. This study was designed to evaluate the efficacy and safety of sintilimab plus S-1 combined intraperitoneal and intravenous paclitaxel. This is an open-label, single-center, phase II study including 36 gastric adenocarcinoma patients with peritoneal metastases diagnosed by laparoscopy. All enrolled patients received sintilimab, intraperitoneal and intravenous paclitaxel plus oral S-1 every 3 weeks. Conversion operation should be considered when a patient responds to the regimen and the peritoneal metastasis disappears. After gastrectomy, the protocol treatment is repeated until disease progression, unacceptable toxicity, investigator decision or patient withdrawal. The primary end point is the 1-year survival rate. Clinical Trial Registration: NCT05204173 (ClinicalTrials.gov).

A phase III trial of neoadjuvant intraperitoneal and systemic chemotherapy for gastric cancer with peritoneal metastasis.

Although recent advances in systemic chemotherapy have improved the clinical outcomes of gastric cancer patients with peritoneal metastasis, the peritoneum still represents a common site of treatment failure and disease recurrence. Neoadjuvant intraperitoneal-systemic chemotherapy has been acknowledged as a more aggressive treatment for gastric cancer patients with peritoneal metastasis. In this multicenter phase III randomized controlled trial, 238 patients will be randomly separated into two groups in a 2:1 ratio after laparoscopic exploration. The experimental arm will receive the proposed neoadjuvant intraperitoneal-systemic chemotherapy regimen, whereas the control group will receive a Paclitaxel + S-1 (PS) chemotherapy regimen. The endpoints for the study are overall survival, response rate, gastrectomy radicality rate, progression-free survival and adverse events.

Recent advances in technology have improved the outcomes of stomach cancer patients. However, there are still many patients who die of cancer that has spread from another part of the body. Neoadjuvant intraperitoneal­systemic chemotherapy has been acknowledged as a more aggressive treatment for stomach cancer patients with peritoneal metastasis (cancer that has spread to the very thin layer of tissue on the inside of the abdomen that covers the stomach and other organs). In this study, 238 patients will be randomly separated into two groups in a 2:1 ratio after evaluation. The experimental group will receive the proposed neoadjuvant intraperitoneal­systemic chemotherapy regimen, whereas the control group will receive a Paclitaxel + S-1 (PS) chemotherapy regimen. The endpoints for the study are how long patients live, number of patients who respond to treatment, number of patients who undergo surgery, how long patients live without their disease getting worse and problems caused by treatment. Trial registration number: ChiCTR-IIR-16009802.

A phase II study of perioperative treatment in gastric cancer with No.16a2/b1 lymph node metastasis: DRAGON-06 trial.

Although gastric cancer with para-aortic lymph node (PAN) metastasis is commonly regarded as unresectable, surgeons have explored the optimal treatment for patients with PAN metastases limited to No.16a2/b1 in the past few decades. Preoperative systemic therapy combined with D2 gastrectomy plus PAN dissection may improve the prognosis of these patients. In this multicenter phase II trial, 29 gastric cancer patients with PAN metastasis limited to No.16a2/b1 will receive preoperative treatment with nab-paclitaxel, oxaliplatin, S-1 (nab-POS: nab-paclitaxel, oxaliplatin, S-1) and sintilimab followed by D2 gastrectomy plus PAN dissection; and postoperative treatment with oral S-1, intravenous sintilimab and intraperitoneal paclitaxel. The end points for the study are 3-year overall survival, 3-year disease-free survival, pathological response rate, incidence of postoperative complications and adverse events.

Stomach cancer with metastases in the para-aortic lymph nodes is usually considered inoperable. Chemotherapy combined with resection of the stomach and more extensive lymph node dissection may prolong the life of these patients. In this multicenter study, 29 stomach cancer patients with para-aortic lymph node metastases will receive preoperative treatment with nab-paclitaxel, oxaliplatin, S-1 and sintilimab, followed by resection of the stomach combined with para-aortic lymph node dissection and use of continued oral, intravenous and intraperitoneal chemotherapy. The study's end points are 3-year overall survival, 3-year disease-free survival, pathological response rate, incidence of postoperative complications and adverse events. Clinical Trial Registration: ChiCTR2200061125 (ChiCTR.org.cn).

Oxaliplatin plus S-1 with intraperitoneal paclitaxel for the treatment of Chinese advanced gastric cancer with peritoneal metastases.

BACKGROUND: In this study, we tried to access the efficacy and safety of oxaliplatin plus S-1 with intraperitoneal paclitaxel (PTX) for the treatment of Chinese advanced gastric cancer with peritoneal metastases. PATIENTS AND METHODS: Thirty patients diagnosed with advanced gastric cancer underwent laparoscopic exploration and were enrolled when macroscopic disseminated metastases (P1) were confirmed. PTX was diluted in 1 l of normal saline and IP administered through peritoneal port at an initial dose of 40 mg/m2 over 1 h on day1,8, respectively. Oxaliplatin was administered intravenously at an initial dose of 100 mg/m2 on day1, and S-1 was administered orally at an initial dose of 80 mg/m2 for 14 days followed by 7 days rest, repeated by every 3 weeks. RESULTS: Of all these 30 patients, the median number of cycles was 6 (range 2-16) due to the limitation of hematotoxicity and peripheral neuropathy by oxaliplatin. There were 11 (36.7%) patients received conversion surgery. The median progression free survival (PFS) was 6.6 months (95% CI = 4.7-8.5 months) and the median overall survival (OS) was 15.1 months (95% CI = 12.4-17.8 months). The grade 3-4 hematological toxicities were leucopenia (23.3%), neutropenia (23.3%), anemia (16.7%), and thrombocytopenia (20%), respectively. The grade 3-4 non-hematological toxicities were tolerated, most of which were peripheral sensory neuropathy (40%) due to oxaliplatin, diarrhea (20%), nausea and vomiting (26.7%). CONCLUSIONS: SOX+ip PTX regimen was effective in advanced gastric cancer with peritoneal metastasis. Survival time was significantly prolonged by conversion surgery. Grade 3-4 toxicities were uncommon. Large scale clinical trial is necessary to get more evidence to identify its efficacy. TRAIL REGISTRATION: ChiCTR, ChiCTR-IIR-16009802 . Registered 9 November 2016.

A randomized controlled trial to evaluate omentum-preserving gastrectomy for patients with T1-T3 gastric cancer.

Although complete omentectomy is traditionally performed in patients with gastric cancer as part of radical gastrectomy to ensure the elimination of micrometastases, the prognostic value of omentectomy during gastrectomy remains unclear. Retrospective studies have shown that the incidence of metastases in the greater omentum is very low in T1-T3 gastric cancer. Thus radical gastrectomy with D2 lymphadenectomy and preservation of the greater omentum may be a proper curative treatment for gastric cancer patients with T1-T3 tumors. The aim of this article is to describe the design and rationale for this prospective, randomized controlled DRAGON-05 trial, conducted to evaluate the prognostic value of omentum-preserving gastrectomy for patients with T1-T3 gastric cancer. Clinical trial registration: ChiCTR2000040045 (ClinicalTrials.gov).

Pressure vector sensor based on an orthogonal optical path Sagnac interferometer.

A novel pressure vector sensor based on a short section of PANDA fiber with an orthogonal optical path Sagnac interferometer structure is proposed and experimentally demonstrated. The sensor structure was realized using a gold film, coated on the end of the fiber tip through the magnetron sputtering method. The birefringence-dependent interference dip is sensitive to external force. Therefore, pressure can be monitored by this sensor. The relationship between the force direction and the pressure sensitivity was studied. We embedded the sensor in aluminum, using ultrasonic consolidation technology, to investigate the application of its sensing properties in metal. Based on this, the influence of the embedding direction on the polarization characteristics of the fiber was analyzed. The experimental results showed that the sensor offered a high sensitivity of 2330 pm/(N·m) in its freeform and 780 pm/(N·m) after being embedded in aluminum. Due to its simple fabrication process, low cost, and high sensitivity, the pressure sensor described in this paper could be a competitive candidate in several pressure sensing applications.

Metallic structure functional sensor based on embedded PANDA fiber by ultrasonic additive manufacturing.

The aim of this study is to embed PANDA fiber into metal aluminum by using the ultrasonic additive manufacturing (UAM) technique. The functional sensing characteristics of the metallic structure were realized by structure design, precise positioning, and laying of the optical fiber and a tip coating (gold film) technique. The sensing characteristics of the metallic structure sensor including temperature, bending, tensile straining, and twist responses have been systematically investigated. Experimental results show that moderate sensitivity, good repeatability, and exactly linear spectral responses are obtained with -476.2pm/∘C for temperature, 1304pm/m-1 for bending, 0.6314pm/µÎµ for tensile straining, and -332.3pm/(rad/m) for twisting. Based on its simple fabrication process and multifunctional measurement, it is clearly demonstrated that the metallic matrix structure with embedded PANDA fiber produced by the UAM technique is a functional structure with capabilities to monitor the structure health conditions and mechanical operation changes in applications.

Prediction of platinum-resistance patients of gastric cancer using bioinformatics.

Lack of guidelines for personalized chemotherapy treatment after surgery has caused gastric cancer (GC) patients' unnecessary exposure to toxicity and the financial burden of chemotherapy treatments. In our study, we aimed to identify potential biomarkers to predict GC patients' susceptibility to platinum-based on Gene Expression Omnibus (GEO) data sets. A total of 603 differentially expressed genes (DEGs) were identified between platinum-resistant cell lines and platinum-sensitive cell lines based on the Cancer Cell Line Encyclopedia (CCLE) data sets. A total of 253 patients who had accepted radical gastrectomy were recruited, of which 97 received platinum-based chemotherapy and 156 were untreated. Three biomarkers (BRMS1, ND6, SRXN1) were then selected by univariate and multivariate Cox regression analysis to establish the predictive models using nomogram. Then this model was further validated through the GEO data set (GSE62254) which showed that this model could precisely predict the disease-free survival and overall survival of patients treated with platinum-based chemotherapy after surgery compared with untreated GC patients (P < 0.0001). This predictive model might provide helpful messages about the patients' susceptibility to platinum to guide personalized chemotherapy.

Resveratrol improved the developmental potential of oocytes after vitrification by modifying the epigenetics.

Resveratrol (Res) has been reported to be able to improve oocyte vitrification because of its antioxidative properties. The objective of this study was to further assess the positive effect of Res addition on the developmental potential of vitrified mouse oocytes from the perspective of epigenetic alterations. First, 2 µM Res was chosen as the optimal concentration on the basis of its effects on survival and its antioxidative properties. We found that Res addition significantly promoted fertilization (63.8% vs. 42.9%) and blastocyst formation (68.3% vs. 50.2%) after oocyte vitrification. The quality of the derived blastocysts was also higher after Res treatment. Regarding epigenetic aspects, the expression of the important deacetylase SIRT1 was found to decrease significantly upon vitrification, but it was rescued by Res. The abnormal levels of H3K9 acetylation and DNA methylation in vitrified oocytes were restored by Res addition. Moreover, the expression of several imprinted genes was affected by oocyte vitrification. Among them, abnormal Gtl2 and Peg3 expression levels were restored by Res addition. Therefore, the methylation of their imprinted control regions (ICRs) was examined. Surprisingly, the abnormal patterns of Gtl2 and Peg3 methylation in blastocysts developed from vitrified oocytes were both restored by Res addition. Finally, the full-term embryonic development showed that the birth rate was improved significantly by Res addition (56.2% vs. 38.1%). Collectively, Res was beneficial for the pre- and postimplantation embryonic development. Except for the antioxidative activity, Res also played a role in the correction of some abnormal epigenetic modifications caused by oocyte vitrification.

The effects of TETs on DNA methylation and hydroxymethylation of mouse oocytes after vitrification and warming.

Oocyte vitrification has extensively been applied in the field of embryo engineering and in the preservation of genetic resources of fine livestock. Following our previous work in oocyte vitrification and the level change of DNA methylation, here we further explored the dynamic change of three active demethylation proteins: Ten-Eleven-Translocation 1/2/3(TET1/2/3), 5-methylcytosine (5 mC) and 5-hydroxymethycytosine (5hmC) after vitrification and warming. In order to observe the active demethylation in vitrified oocytes, two small molecular regulators, i.e. Vitamin C (VC) and dimethyloxaloylglycine (DMOG) were used to adjust activity and level of the TET 3 protein. The results showed that the levels of 5 mC and 5hmC were significantly decreased after 2 h of vitrification (P < 0.01). Moreover, the level of TET3 protein was significantly increased after 2 h warming (P < 0.01). And the relative gene expression of TET2/3 did not change in the first 2 h, but significantly increased after 2 h (P < 0.01). When VC was added to vitrification and recovery medium, it could not significantly improve the level of TET3 gene expression, and affect 5 mC and 5hmC expression (P > 0.05). When the DMOG was added to the solutions of vitrification, the level of 5hmC showed significantly increase (P < 0.01). In conclusion, the oocyte vitrification procedure reduced DNA methylation and hydroxymethylation in MII oocytes, but adding VC and DMOG to vitrification medium can prevent the reduction of DNA hydroxymethylation by increasing activity of TET3 methylation protein after vitrification and warming.

Hybrid Mesoporous-Microporous Nanocarriers for Overcoming Multidrug Resistance by Sequential Drug Delivery.

Combination chemotherapy with a modulator and a chemotherapeutic drug has become one of the most promising strategies for the treatment of multidrug resistance (MDR) in cancer therapy. However, the development of nanocarriers with a high payload and sequential release of therapeutic agents poses a significant challenge. In this work, we report a type of hybrid nanocarriers prepared by polydopamine (PDA) mediated integration of the mesoporous MSN core and the microporous zeolite imidazolate frameworks-8 (ZIF-8) shell. The nanocarriers exploit storage capacities for drugs based on the high porosity and molecular sieving capabilities of ZIF-8 for sequential drug release. Particularly, large amounts of an anticancer drug (DOX, 607 µg mg-1) and a MDR inhibitor curcumin (CUR, 778 µg mg-1) were sequentially loaded in the mesoporous core via π-π stacking interactions mediated by PDA and in the microporous shell via the encapsulation during ZIF-8 growth. The sustained release of DOX was observed to follow earlier and faster release of CUR by acid-sensitive dissolution of the ZIF-8 shell. Furthermore, the nanoparticles showed good biocompatibility and effective cellular uptake in in vitro evaluations using drug-resistant MCF-7/ADR cancer cells. More importantly, the preferentially released CUR inhibited the drug efflux function of the membrane P-glycoprotein (P-gp), which subsequently facilitated the nuclear transportation of DOX released from the PDA-MSN core, and, in turn, the synergistic effects on killing MDR cancer cells. The hybrid mesoporous-microporous nanocarrier holds great promise for combination chemotherapy applications on the basis of sequential drug release.

Fluorescent miRNA analysis enhanced by mesopore effects of polydopamine nanoquenchers.

The combination of fluorophore-labelled single-strand DNA probes and nanomaterial quenchers has shown great potential in miRNA detection. The development of advanced detection systems by understanding and controlling the fluorescence quenching/recovery via nanoquenchers' microstructures and local morphologies is an attractive area warranting further investigations. Inspired by nanopore sequencing, we present a novel miRNA sensing strategy using fluorophore-labeled DNA as probes and a type of large-pore-sized mesoporous polydopamine nanoparticles (MPDA-L, 70 nm in diameter) as fluorescence quenchers. It is revealed that the quenching efficiency of MPDA-L towards the fluorophore labelled on the probe, reached more than 99% at a relatively low particle concentration. Moreover, the mesopores effectively protected the probe DNA from cleavage by DNase I which was used for signal amplification. Sensitive detection of miRNA with a low detection limit of 32-40 pM, as well as a linear detection range of up to 5 nM, was realized by the mesopore effects via a greatly improved differential affinity of ssDNA and the probe-miRNA heteroduplex toward the surface of nanoquenchers. Interestingly, enhanced DLVO (Derjaguin-Landau-Verwey-Overbeek) repulsion generated inside the pore surface by the negative surface-curvature effect correlates with the improved duplex detachment and fluorescence recovery. The developed strategy can be successfully applied to quantify down-regulated let-7a and up-regulated miRNA-21 in different types of cancer cells by using total RNA samples from cell lysate. These findings are expected to inspire strategies and pave a way for utilizing porous nanomaterials for constructing miRNA detection systems.