Preparation and characterization of POSS-containing poly(perfluoropolyether)methacrylate hybrid copolymer and its superhydrophobic coating performance

To design a mechanically stable and superhydrophobic coating, a polyhedral oligomeric silsesquioxane (POSS)-containing poly(perfluoropolyether)methacrylate (PFPEM) hybrid copolymer (PFPEM–POSS) was synthesized via a free-radical solution polymerization with PFPEM, 1H,1H,2H,2H-perfluorooctyl acrylate, methyl (meth)acrylate, n-butyl acrylate, hydroxypropyl acrylate, methacryloxy propyl trimethoxy silane, and methacrylisobutyl POSS; and azobisisobutyronitrile as an initiator. Hydrophobic coatings were formed on substrates by a facile one-step dip-coating method in a solution mixture of diethylene glycol dimethyl ether with the PFPEM–POSS hybrid copolymer. The chemical structure of the PFPEM–POSS copolymer and the surface morphology and performance of the PFPEM–POSS coatings were investigated. The results indicate that, under POSS aggregation via the fluorophilic/oleophilic co-monomer phase separation and owing to the low-surface-energy poly(perfluoropolyether)methacrylate incorporated into the copolymer, PFPEM–POSS exhibited a hierarchical micro-nano roughness in atomic force microscopy observations and provided the treated substrates with excellent hydrophobicity and abrasion resistance. As a result, the water contact angle reached 152.3° on the treated glass.

A coating with excellent superhydrophobicity and durability was built via incorporating an environmentally-friendly poly(perfluoropolyether)methacrylate copolymer into polyhedral oligomeric silsesquioxane (POSS).     

Targeted drug release system based on pH-responsive PAA-POSS nanoparticles

An amphipathic PAA-POSS@DOX drug delivery system that responds sensitively to pH changes in the cancer microenvironment has been developed using a nanoparticle based on inorganic polyhedral oligomeric silsesquioxane (POSS). POSS was introduced to the carboxylic acid group of polyacrylic acid to which doxorubicin anticancer drug was loaded to prepare 480 ± 192 nm self-assembled nanoparticles. PAA-POSS had a high loading efficiency of over 75% and doxorubicin was quickly released to the target area responding sensitively to weakly acidic conditions. The possibility of employing PAA-POSS as a targeted drug delivery system has been confirmed by observing the death of cells of the MDA-MB-231 breast cancer line.

pH-sensitive PAA-POSS@DOX nanoparticles were synthesized and showed high loading efficiency of over 75% and doxorubicin was quickly released to the target area. The ability of PAA-POSS@DOX to kill MDA-MB-231 breast cancer cells has been demonstrated.     

POSS-enhanced thermosensitive hybrid hydrogels for cell adhesion and detachment

Thermosensitive poly(N-isopropylacrylamide) (PNIPAM)-based substrates have presented great promise in cell sheet engineering. However, non-functionalized PNIPAM cannot be well applied for cell cultivation, due to the low cell adhesion. Herein, to enhance PNIPAM-based substrates and to promote cell proliferation and detachment, a polyhedral oligomeric silsesquioxane (POSS) nanoscale inorganic enhanced agent has been introduced into PNIPAM matrices to construct POSS-containing hybrid hydrogels. The hydrogels were facilely prepared using POSS as a cross-linker via one-pot crosslinking reaction under UV irradiation. The swelling behavior, thermal stability and the mechanical properties of POSS–PNIPAM hybrid hydrogels have been evaluated and they are all dependent on the content of POSS. The in vitro experiment confirms that human amniotic mesenchymal stem cells (hAMSCs) exhibit clearly enhanced adhesion and proliferation on the substrates of POSS–PNIPAM hybrid hydrogels in comparison to the pure PNIPAM hydrogel without POSS. Based on the thermal-responsiveness of PNIPAM, the proliferated cells are easily released without damage from the surface of hybrid hydrogels. Therefore, POSS-enhanced PNIPAM hybrid hydrogels provide a unique approach for harvesting anchorage dependent stem cells.

Thermosensitive poly(N-isopropylacrylamide) (PNIPAM)-based substrates have presented great promise in cell sheet engineering.     

Open-tubular capillary electrochromatography with hydroxypropyl-β-cyclodextrin imprinted polymers: hybrid polyhedral oligomeric silsesquioxane as a coating for enantioseparation

A hydroxypropyl-β-cyclodextrin (HP-β-CD) imprinted coating based on polyhedral oligomeric silsesquioxane (POSS) for open tubular electrochromatography was prepared. The mixture of methacryl-POSS (MA0735), HP-β-CD (template), methacrylic acid (MAA, monomer), N,N′-methylenebisacrylamide (MBA, crosslinker) and toluene-dimethyl sulfoxide (porogen) was used to synthesize the chiral selective coating. The influence of synthesis parameters on the imprinting effect and separation performance, including the amount of HP-β-CD, POSS, and MAA, was investigated systemically. The optimum polymerization was prepared by mixing HP-β-CD, MA0735, MAA, and MBA with the molar ratio of 1 : 1.87 : 1.60 : 1.60. Five racemates were separated by the modified capillary columns using aqueous buffer. Column efficiency on the POSS-based MIPs coating column was greater than 22 000 plates/m. MIPs-POSS hybrid coating capillaries had improved resolution (3.36 times) and the greatest resolution was up to 6.15 within 10 min.

A hydroxypropyl-β-cyclodextrin (HP-β-CD) imprinted coating based on polyhedral oligomeric silsesquioxane (POSS) for open tubular electrochromatography was prepared.     

Dual-modal imaging and excellent anticancer efficiency of cisplatin and doxorubicin loaded NaGdF4:Yb3+/Er3+ nanoparticles

NaGdF₄:Yb³⁺/Er³⁺ nanoparticles were synthesized via a modified hydrothermal route. The dependence of structure and morphology on the dosage of sodium polyacrylate was studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The as-prepared nanoparticles could be used for T₂ weighted magnetic resonance imaging due to the paramagnetism of Gd³⁺. cis-dichlorodiamineplatinum (CDDP) could be loaded onto NaGdF₄:Yb³⁺/Er³⁺ nanoparticles through binding carboxyl in the form of Pt–O bonds, and doxorubicin (DOX) could be loaded via hydrogen bonding. DOX could also be loaded onto the NaGdF₄–CDDP composite in the same manner, and the loading efficiency of both drugs remained unchanged. Three as-prepared drug delivery systems were used for tumor inhibition both in vitro and in vivo, and the results indicated that NaGdF₄–CDDP–DOX displayed the greatest inhibitory capacity.

The drug delivery system NaGdF₄–CDDP–DOX showed best tumor inhibition capacity both in vitro and in vivo.     

Morphology and crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polyhedral oligomeric silsesquioxane hybrids

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polyhedral oligomeric silsesquioxane (PHBV/POSS) hybrids with different POSS contents of 5, 10, 15, 20, 25 and 30 wt% were prepared by solution casting. The composition, crystallization and melting behavior, crystal structure, spherulite morphology, surface morphology, and tensile properties of PHBV/POSS hybrids were characterized by EDS, DSC, FTIR, XRD, HSPOM, AFM and a tensile testing machine. The results showed that POSS was well dispersed in the PHBV matrix. PHBV and POSS crystals coexisted in the hybrids. The crystallinity of pure PHBV was larger than that of PHBV/POSS hybrids. POSS restricted the crystallization of PHBV in PHBV/POSS hybrids. With the increase of POSS content, the crystallinity of PHBV/POSS hybrids decreased from 56.8 (pure PHBV) to 33.6% (PHBV/POSS hybrid with 30 wt%). However, the introduction of POSS did not affect the spherulite morphology of PHBV. The Avrami equation was used to describe the isothermal crystallization kinetics of PHBV/POSS hybrids. The results showed that as the crystallization temperature increased, the crystallization rate became slow. In addition, POSS can improve the tensile properties of PHBV.

Polyhedral oligomeric silsesquioxane (POSS) changed the crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and improved the mechanical properties of PHBV.     

The effect of steric repulsion between highly branched hydrophilic blocks on inverse cubic mesophase formation in block copolymers

The solution-based self-assembly of block copolymers (BCPs) into nanoparticulate or microparticulate inverse cubic mesophases, or polymer cubosomes, is of growing interest. This phenomenon could yield new polymeric mesoporous materials with three-dimensionally organized mazes of large water channels. In addition to the ratio of its hydrophilic and hydrophobic blocks, the architecture of a BCP critically influences self-assembly. BCP bilayers having triply periodic minimal surfaces with cubic lattice structures are formed. Here we report the synthesis and self-assembly of BCPs with T8 polyhedral oligomeric silsesquioxane (POSS), an inorganic cage molecule. POSS can be asymmetrically functionalized to host structural modules as branching units of the hydrophilic block that contain various spatial and chemical environments. BCPs, each containing seven poly(ethylene glycol) chains and the hydrophobic polystyrene block PEG350₇-POSS-b-PS, were prepared to investigate the effect of the highly branched hydrophilic block architecture on self-assembly. We found that the BCPs self-assembled into polymer cubosomes. Regardless of the block ratio, only the primitive cubic phase (Schwarz P surface, Im$\bar{3}$m space group) was observed in the cubosomes. This is in contrast to the self-assembly of conventional BCPs into inverse mesophases, in which the internal lattice preferentially transforms into double-diamond lattices to yield a Schwarz D surface as a consequence of block ratio changes. Our results suggest that BCP architecture may be related to the symmetry of the lattice formed via self-assembly in solution.

The solution-based self-assembly of block copolymers (BCPs) into nanoparticulate or microparticulate inverse cubic mesophases, or polymer cubosomes, is of growing interest.     

A doxorubicin–platinum conjugate system: impacts on PI3K/AKT actuation and apoptosis in breast cancer cells

In recent years, the development of a nano-conjugate system for drug delivery applications has gained attention among researchers. Keeping this in mind, in this study, we developed a doxorubicin–platinum conjugate system that targeted breast cancer cell lines. To achieve this, we developed platinum nanoparticles using polyvinylpyrrolidone (PVP). High resolution-transmission electron microscopy (HR-TEM) revealed the occurrence of octopod-shaped platinum nanoparticles. Subsequently, doxorubicin (DOX) was conjugated on the surface of the as-prepared platinum octopods via an in situ stirring method. The physicochemical characterization of the doxorubicin–platinum conjugate system revealed that the PVP of PtNPs interacts with the NH₂ group of doxorubicin via electrostatic interaction/hydrogen bonding. Besides, the doxorubicin–platinum conjugate system exhibited a sustained drug release profile within the cancer cells. Furthermore, the evaluation of the in vitro anticancer efficacy of the doxorubicin–platinum conjugate system in breast cancer cells (MCF-7 and MDA-MB-231) unveiled the induction of apoptosis via intracellular ROS and DNA damage, rather than free DOX and PtNPs. Remarkably, we also perceived that the doxorubicin–platinum conjugate system was strong enough to down-regulate the PI3K/AKT signalling pathway. As a result, the tumour suppressor gene PTEN was activated, which led to the stimulation of a mitochondrion-based intrinsic apoptotic pathway and its downstream caspases, triggering cell death. Hence, our findings suggested that a biologically stable doxorubicin–platinum conjugate system could be an imperative therapeutic agent for anticancer therapy in the near future.

In recent years, the development of a nano-conjugate system for drug delivery applications has gained attention among researchers.     

Toughening of POSS–MPS composites with low dielectric constant prepared with structure controllable micro/mesoporous nanoparticles

In this work, we developed a modified calcination and extraction method to obtain controllable micro/mesoporous nanoparticle samples POSS–MPS, which were synthesized through glycidyl polyhedral oligomeric silsesquioxane (G-POSS) grafting with aminopropyl-functionalized mesoporous silica (AP-MPS). The POSS–MPS was introduced into the cyanate ester (CE) matrix to optimize the dielectric properties and enhance the toughness of the POSS–MPS/CE nanocomposite. The structure of the hybrid was characterized by FTIR and SEM. The dispersion properties, mechanical properties, dielectric properties and thermal performance were also studied. The results showed that both the C-POSS–MPS and E-POSS–MPS uniformly distribute in the CE matrix with the content of 0.5–4 wt%. The impact strength increased 52% and 60% separately with 2 wt% C-POSS–MPS and E-POSS–MPS addition respectively. The introduction of E-POSS–MPS particles can significantly decrease the dielectric loss value of the POSS–MPS/CE composites to 0.00498, which is of potential in wave transparent composites and structures.

A promising method to improve the performance of CE composites via combining advantages of POSS and MPS.     

Liposomes co-delivery system of doxorubicin and astragaloside IV co-modified by folate ligand and octa-arginine polypeptide for anti-breast cancer

Doxorubicin (DOX) is one of the core drugs in triple-negative breast cancer (TNBC) chemotherapy, but its resistance has severely limited its clinical application. Our previous study found that astragaloside IV (AS-IV) has a good reversal effect on doxorubicin resistance. In order to encapsulate DOX and AS-IV simultaneously, a new liposome-targeted co-delivery system co-modified by the folate ligand (FA) and octa-arginine polypeptide (R8) (FA-R8-LPs, for short) was prepared. In this co-delivery system, R8 not only served as a bond connecting the FA to the liposome, but also played the role of cell penetrating peptides (CPPs). This design effectively increased the tumor targeting and cellular uptake capacity of liposomes. The results of the cytotoxicity test indicated that FA-R8-LPs significantly inhibited the proliferation of the DOX resistant cell line MDA-MB-231/DOX in vitro. In nude mice tumor models inoculated with MDA-MB-231/DOX cells, FA-R8-LPs significantly inhibited tumor growth, and overcame doxorubicin resistance, exhibiting excellent antitumor effects. This study demonstrates that liposome-targeted co-delivery systems based on FA and R8 double modifying may provide a new and effective strategy for the treatment of TNBC, which is of great significance for drug combination.

To more efficiently co-deliver DOX and AS-IV, R8 was used as a “connecting bridge” to connect FA with cholesterol. A new liposome-targeted co-delivery system, co-modified by FA and R8 (FA-R8-LPs, for short), was prepared.     

Self-assembly of the monohydroxy triterpenoid lupeol yielding nano-fibers,sheets and gel: environmental and drug delivery applications

Lupeol is a medicinally important naturally abundant triterpenoid having a 6–6–6–6–5 fused pentacyclic backbone and one polar secondary “–OH” group at the C3 position of the “A” ring. It was extracted from the dried outer bark of Bombax ceiba and its self-assembly properties were investigated in different neat organic as well as aquous-organic binary liquid mixtures. The triterpenoid having only one polar “–OH” group and a rigid lipophilic backbone self-assembled in neat organic non-polar liquids like n-hexane, n-heptane, n-octane and polar liquids like DMSO, DMF, DMSO–H₂O, DMF–H₂O, and EtOH–H₂O yielding supramolecular gels via formation of nano to micrometre long self-assembled fibrillar networks (SAFINs). Morphological investigation of the self-assemblies was carried out by field emission scanning electron microscopy, high resolution transmission electron microscopy, atomic force microscopy, optical microscopy, concentration dependent FTIR and wide angle X-ray diffraction studies. The mechanical properties of the gels were studied by concentration dependent rheological studies in different solvents. The gels were capable of removing toxic micro-pollutants like rhodamine-B and 5,6-carboxyfluorescein as well as the toxic heavy metal Cr(vi) from contaminated water. Moreover release of the chemotherapeutic drug doxorubicin from a drug loaded gel in PBS buffer at pH 7.2 has also been demonstrated by spectrophotometry.

The monohydroxy triterpenoid lupeol forms gels in organic and aqueous organic liquids via self-assembly. The resulting supramolecular gels could be utilized for pollutant capture, drug entrapment and release applications.     

Highly selective cross-coupling reactions of 1,1-dibromoethylenes with alkynylaluminums for the synthesis of aryl substituted conjugated enediynes and unsymmetrical 1,3-diynes

A highly efficient method for the synthesis of aryl substituted conjugated enediynes and unsymmetrical 1,3-diynes via selective cross-coupling reactions of 1,1-dibromoethylenes with alkynylaluminums using the Pd(OAc)₂–DPPE and Pd₂(dba)₃–TFP complexes as catalysts, respectively, has been successfully developed. Though the alkyl substituted conjugated enediynes and unsymmetrical 1,3-diynes were not obtained, this case is also remarkable as the same starting materials could selectively produce either aryl substituted conjugated enediynes or unsymmetrical 1,3-diynes in moderate to excellent yields (up to 99%) in the different Pd–phosphine catalytic systems.

A highly efficient method for the synthesis of aryl substituted conjugated enediynes and unsymmetrical 1,3-diynes via selective cross-coupling reactions of 1,1-dibromoethylenes with alkynylaluminums has been successfully developed.     

Synergetic effect of photocatalysis and peroxymonosulfate activated by MFe2O4 (M = Co,Mn, or Zn) for enhanced photocatalytic activity under visible light irradiation

Nanosized MFe₂O₄ (M = Co, Mn, or Zn) photocatalysts were synthesized via a simple sol–gel method. MFe₂O₄ photocatalysts exhibited lower photocatalytic activity for the degradation of levofloxacin hydrochloride under visible light irradiation. For enhancement of photocatalytic activity, MFe₂O₄ was used to activate peroxymonosulfate and degrade levofloxacin hydrochloride under visible light irradiation. The influences of peroxymonosulfate dosage, levofloxacin hydrochloride concentration, pH value, and temperature on peroxymonosulfate activation to degrade levofloxacin hydrochloride were investigated in detail. The mechanism of activation of peroxymonosulfate by MFe₂O₄ was proposed and proved by radical quenching experiments, electron spin resonance analysis, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and transient photocurrent responses. The combined activation effects of photogenerated e⁻/h⁺ and transition metals on peroxymonosulfate to produce sulfate radical clearly enhanced the degradation efficiency.

The combined activation effects of photogenerated e⁻/h⁺, Fe, Co, Mn, and Zn on peroxymonosulfate to produce SO₄˙⁻ clearly enhanced the degradation efficiency.     

Copper complexes as prospective anticancer agents: in vitro and in vivo evaluation,selective targeting of cancer cells by DNA damage and S phase arrest

A series of six new bis(thiosemicarbazone)copper(i) complexes of the type [Cu(L^1–6)₂Cl] (1–6) have been synthesized and characterized. The molecular structure of the ligand L⁴ was determined by the single crystal XRD method. All the complexes adopted trigonal planar (Y-shaped) geometry. All the complexes strongly bind with CT-DNA via intercalative mode, which was further supported by molecular docking studies. Further, the complexes were effectively bind with BSA as observed by UV-Vis and fluorescence spectra. All the complexes effectively cleave pBR322 DNA through hydrolytic pathway as evidenced from T4 ligase experiments. All the complexes interact with the anticancer receptor focal adhesion kinase (FAK) via electrostatic, van der Waals, hydrogen bonding, σ–π and π–π interactions. In vitro cytotoxicity of the complexes were assessed by MTT assay against four cancer cell lines such as human breast adenocarcinoma (MCF-7), cervical (HeLa), epithelioma (Hep-2) and Ehrlich ascites carcinoma (EAC), and two normal cell lines namely normal human dermal fibroblasts (NHDF) and L6 myotubes with respect to the commercially used anticancer drug cisplatin. All the complexes induce apoptosis in EAC cells, which was confirmed by AO/EB, Hoechst 33258 and PI staining methods. The complexes block cell cycle progression of EAC cells in S phase (DNA synthesis). The cellular uptake studies confirmed the ability of the complexes to go into the cytoplasm and accumulation in the cell nuclei. In the in vivo anticancer studies, the complexes significantly reduce the tumour volume in female Swiss albino mice. Overall, our results ensure the role of thiosemicarbazone-based copper(i) complexes as prospective anticancer agents, induction of apoptosis and S phase arrest with the mitochondrial controlled pathway.

The thiosemicarbazone-based copper(i) complexes causing S phase arrest and apoptosis involving the mitochondrial controlled pathway has been investigated.     

Facile synthesis and biological evaluation of tryptamine-piperazine-2,5-dione conjugates as anticancer agents

A facile and efficient route to synthesize N-heterocyclic fused tryptamine-piperazine-2,5-dione conjugates was developed via a post-Ugi cascade reaction. The targeted compounds were prepared by means of a mild reaction and simple operation procedure, which could be applied to a broad scope of starting materials. Compound 6h was demonstrated to induce significant growth inhibition of AsPC-1 and SW1990 human pancreatic cancer cell lines (IC₅₀ = 6 ± 0.85 μM). Our protocol allows for the construction of a structurally diverse compound library and paves a new avenue for the discovery of pancreatic cancer drug candidates.

A series of tryptamine-piperazine-2,5-dione conjugates derivatives was designed and synthesized via Ugi cascade reaction. The discovery of compound 6h may provide a new avenue for pancreatic cancer drug discovery.     

Folic acid and deoxycholic acid derivative modified Fe3O4 nanoparticles for efficient pH-dependent drug release and multi-targeting against liver cancer cells

The novel nano-drug carrier (FDCA-FA-MNPs) was constructed by grafting formyl deoxycholic acid (FDCA) and folic acid (FA) on the surface of Fe₃O₄ magnetic nanoparticles (MNPs), possessing the advantages of superparamagnetism, good stability, low cytotoxicity and good blood compatibility. The hydrophobic anti-cancer drug doxorubicin hydrochloride (DOX) was successfully loaded onto FDCA-FA-MNPs through supramolecular interactions (hydrogen bond between FDCA and drug and hydrophobic interaction and π–π stacking between drug and drug). The drug loading amount and drug loading capacity were 509.1 mg g⁻¹ and 33.73 wt%, respectively. In addition, drug release had a pH responsive and controllable release performance, the release rate at pH 5.3 (45.6%) was four times that at pH 7.4 (11.5%), and the tumor microenvironment was favorable for drug release. More importantly, the novel nano-drug carrier combined the hepatocellular targeting of FDCA, the cancer cell targeting of FA, and the magnetic targeting of Fe₃O₄, showing excellent cancer-killing efficiency (78%) in vitro. Therefore, the nano-drug carrier synthesized in this paper has potential practical application value in the targeted therapy of liver cancer.

A nano-drug carrier, FDCA-FA-MNPs was constructed by modifying Fe₃O₄ magnetic nanoparticles (MNPs) with formyl deoxycholic acid (FDCA) and folic acid (FA) with double-targeting, pH-triggered drug release and excellent tumor cell killing efficiency.     

A novel coordination mode of κ1-N-Br-pyridylbenz-(imida,oxa or othia)-zole to Pt(ii): synthesis,characterization, electrochemical and structural analysis

Herein, three novel Pt(ii) complexes with formula [trans-Pt(Br-PyBenz-X)(Cl)₂(DMSO)] (1–3) having Br-pyridylbenz-(imida, oxa or othia)-zole (L_1–3) derivatives as potential bidentate ligands, under an unusual κ¹-N-coordination mode are reported. All compounds were obtained straightforwardly via reaction of corresponding L_PB1–3 and [Pt(Cl)₂(DMSO)₂] (DMSO = dimethyl sulfoxide), at 100 °C in acetonitrile, respectively. 1–3 complexes were characterized by analytical and spectroscopic data: melting point, FT-IR, Raman, UV/Vis and NMR experiments. Cyclic voltammetry studies show an irreversible two-electron process at −0.50 and −0.51 V, which was ascribed to the Pt(ii)/Pt(iv) couple, for complexes 2 and 3. The crystal structure of complex 2 was elucidated by single-crystal X-ray diffraction, where the platinum atom exhibits a square plane geometry, where L_PB2 adopts an unusual mono-coordinated mode via an N-κ¹-benzoxazole ring. According to DFT calculations the first N-coordination exchanging one DMSO molecule is favourable, while the second N-coordination is highly impeded.

Three novel platinum(ii) complexes with the general formula [trans-Pt(Br-PyBenz-X)(Cl)₂(DMSO)] containing Br-pyridylbenz(imida, oxa or othia)zole derivatives, under an unusual N-κ¹-coordination mode were synthesized.     

Therapeutic polymeric nanomedicine: GSH-responsive release promotes drug release for cancer synergistic chemotherapy

To obtain an efficient dual-drug release and enhance therapeutic efficiency for combination chemotherapy, a glutathione (GSH)-responsive therapeutic amphiphilic polyprodrug copolymer (mPEG-b-PCPT) is synthesized to load doxorubicin (DOX) via hydrophobic and π–π stacking interaction. In this nanomedicine system (mPEG-b-PCPT/DOX), the ratio of the two drugs can be easily modulated by changing the loading content of DOX. The in vitro drug release curves and laser confocal images suggested that the release of CPT and DOX is induced through a “release promotes release strategy”: after internalization into tumor cells, the disulfide bonds in the nanomedicine are cleaved by glutathione (GSH) in the cytoplasm and then lead to the release of CPT. Meanwhile, the disassembly of nanomedicine immediately promotes the co-release of DOX. The optimum dose ratio of CPT and DOX is evaluated via the combination index (CI) value using HepG-2 cells. The results of cell apoptosis and cell viability prove the better synergistic efficiency of the nanomedicine than free drugs at the optimum dose ratio of 1. Consequently, this stimuli-responsive synergistic chemotherapy system provides a direction for the fabrication of nanomedicines possessing promising potential in clinical trials.

In the GSH-responsive doxorubicin loading camptothecin prodrug nanomedicine, easy modulation of the dose ratio and controlled co-release were achieved, and the synergistic effect was significantly improved.     

Synthesis,crystal structures,HF-EPR,and magnetic properties of six-coordinate transition metal (Co,Ni, and Cu) compounds with a 4-amino-1,2,4-triazole Schiff-base ligand

We have synthesized a series of transition metal compounds [M(L)₂(H₂O)₂] (M = Co (1), Ni (2), and Cu (3)) by using the 4-amino-1,2,4-triazole Schiff-base ligand via the hydrothermal methods. They are all mononuclear compounds with the octahedral geometry. Direct-current magnetic and HF-EPR measurements were combined to reveal the negative D values (–28.78 cm⁻¹, –10.79 cm⁻¹) of complexes 1 and 2, showing the easy-axis magnetic anisotropies of compounds 1 and 2. Applying a dc field of 800 Oe at 2.0 K, the slow magnetic relaxation effects were observed in compound 1, which is a remarkable feature of single-ion magnets.

We have synthesized a series of transition metal compounds [M(L)₂(H₂O)₂] (M = Co (1), Ni (2), and Cu (3)) by using the 4-amino-1,2,4-triazole Schiff-base ligand via the hydrothermal methods.     

The morphologies and fluorescence quantum yields of perylene diimide dye-doped PS and PHVB microspheres

Aggregation and continuous π-stacking have been the major obstacles hindering the fluorescence (FL) quantum yield (Φ_F) of perylene diimide (PDI) derivatives in the condensed phase. To prepare polymer microspheres with nearly unity Φ_F, in this work a POSS functionalized PDI derivative, POSS–PDI–POSS (PPP), was applied as the red fluorophore of poly(3-hydroxylbutyrate-co-3-hydroxyvalerate) (PHBV) and polystyrene (PS) microspheres. The electrosprayed PPP/PHBV and PPP/PS microspheres have unique hollow structures. Moreover, they show bright red FL under a fluorescence microscope. A photophysical study of the microspheres indicates a significant role of the polymer matrix in disrupting the aggregation state and the Φ_F of the embedded PPP fluorophore. Both the PPP/PHBV and the PPP/PS microspheres show higher Φ_F than most PDI materials in the condensed phase. The PPP/PHBV microspheres show Φ_F of 28%, whereas the PPP/PS microspheres give nearly unity Φ_F.

A POSS functionalized perylene diimide (PDI) derivative, PPP, is applied to polymer microspheres as a red fluorophore. Hollow PPP/polystyrene microspheres show a fluorescence quantum yield (Φ_F) of nearly unity.