Chemophototherapeutic Ablation of Doxorubicin-Resistant Human Ovarian Tumor Cells†

Porphyrin-phospholipid (PoP) liposomes loaded with Doxorubicin (Dox) have been demonstrated to be an efficient vehicle for chemophototherapy (CPT). Multidrug resistance (MDR) of cancer cells is a problematic phenomenon in which tumor cells develop resistance to chemotherapy. Herein, we report that Dox-resistant tumor cells can be ablated using our previously described formulation termed long-circulating Dox loaded in PoP liposomes (LC-Dox-PoP), which is a PEGylated formulation containing 2 mol. % of the PoP photosensitizer. In vitro studies using free Dox and LC-Dox-PoP showed that human ovarian carcinoma A2780 cells were more susceptible to Dox compared to the corresponding Dox-resistant A2780-R cells. When CPT was applied with LC-Dox-PoP liposomes, effective killing of both nonresistant and resistant A2780 cell lines was observed. An in vivo study to assess the efficiency of LC-Dox-PoP showed effective tumor shrinkage and prolonged survival of athymic nude mice bearing subcutaneous Dox-resistant A2780-R tumor xenografts when they were irradiated with a red laser. Biodistribution analysis demonstrated enhanced tumoral drug uptake in Dox-resistant tumors with CPT, suggesting that increased drug delivery was sufficient to induce ablation of resistant tumor cells.     

Synthesis and release behavior of composites of camptothecin and layered double hydroxide

A simple method, reconstruction of calcinated layered double hydroxides (CLDH) in an organic (ethanol)-water mixed solvent medium containing drug, was developed to intercalate partially a non-ionic and poorly water-soluble drug (camptothecin) into the gallery of layered double hydroxides (LDHs) to form the drug-LDH composites. The purpose of choosing organic-water mixed solvent is to increase remarkably the solubility of camptothecin (CPT) in the reconstruction medium. A probable morphology of CPT molecules in the gallery of LDHs is that CPT molecules arrange as monolayer with the long axis parallel to the LDH layers. The in vitro drug release from the composites was remarkably lower than that from the corresponding physical mixture, which shows these drug-inorganic composites can be used as a potential drug delivery system.     

Redox-responsive polymer prodrug/AgNPs hybrid nanoparticles for drug delivery

The redox-responsive hybrid nanoparticles of P(MACPTS-co-MAGP)@AgNPs is developed for drug delivery and fluorescence monitoring of the drug release by applying the NSET-based strategy.     

Preparation of a Camptothecin Prodrug with Glutathione‐Responsive Disulfide Linker for Anticancer Drug Delivery

We present here a novel camptothecin (CPT) prodrug based on polyethylene glycol monomethyl ether‐block‐poly(2‐methacryl ester hydroxyethyl disulfide‐graft‐CPT) (MPEG‐SS‐PCPT). It formed biocompatible nanoparticles (NPs) with diameters of approximately 122 nm with a CPT loading content as high as approximately 25 wt % in aqueous solution. In in vitro release studies, these MPEG‐SS‐PCPT NPs could undergo triggered disassembly and much faster release of CPT under glutathione (GSH) stimulus than in the absence of GSH. The CPT prodrug had high antitumor activity, and another anticancer drug, doxorubicin hydrochloride (DOX ? HCl), could also be introduced into the prodrug with a high loading amount. The DOX ? HCl‐loaded CPT prodrug could deliver two anticancer drugs at the same time to produce a collaborative cytotoxicity toward cancer cells, which suggested that this GSH‐responsive NP system might become a promising carrier to improve drug‐delivery efficacy.     

Fabrication of nanomicelle with enhanced solubility and stability of camptothecin based on α,β-poly[(N-carboxybutyl)-l-aspartamide]–camptothecin conjugate

This research is aimed to develop a nanomicelle delivery system in order to enhance the solubility and stability of camptothecin (CPT) in aqueous media. In this case, α,β-poly[(N-carboxybutyl)-l-aspartamide] (PBAsp)–CPT was conjugated by the esterification between PBAsp and 20-OH of CPT, and hence used to fabricate nanomicelles with a particle size between the pore size of blood capillary in normal tissue and that in tumor tissue. It was worthy of note that the drug-loaded system of PBAsp–CPT nanomicelle improved the solubility and stability of CPT in aqueous media. However, with an increase of the CPT loading in PBAsp–CPT, the solubility sharply decreased. Meanwhile, the sizes of PBAsp–CPT nanomicelles showed a tendency of increase. Moreover, the drug release of PBAsp–CPT nanomicelles displayed a linear sustaining profile, and hence resulted in the essential decrease of cytotoxicity to L929 cell line. The assembled nanomicelles based on the PBAsp–CPT conjugates showed a great potential as polymer prodrug of tumor therapy, and the controlled nano-scale might achieve the passive tumor targeting.     

Efficient intracellular delivery of camptothecin by silica/titania hollow nanoparticles

Silica/titania hollow nanoparticles (HNPs) with 50?nm were fabricated by using the dissolution and redeposition method and modified with anti-[human epidermal growth factor receptor 2] monoclonal antibody (herceptin), and their application as camptothecin (CPT) delivery agents to human breast cancer SK-BR-3 cells was investigated. Although the diameter of herceptin-modified HNPs (HER-HNP) is smaller than that of other reported mesoporous silica nanoparticles, the extensive hollow cavity of HNPs (ca. 30?nm) allowed the loading of a large amount of CPT. CPT-loaded HER-HNP (HER-HNP-CPT) did not release CPT in phosphate-buffered saline over a period of 24?h, however, HER-HNP-CPT in a hydrophobic solvent released its entire load of CPT. In addition, HER-HNPs were efficiently internalized owing to their herceptin conjugation and optimized size. To evaluate in vitro antitumor efficacy, apoptosis/necrosis and viability of HER-HNP-CPT-treated cells were investigated. When the cells were treated with HER-HNP-CPT for 30?min, a few apoptotic cells were observed. After 24?h, the viability of HER-HNP-CPT-treated SK-BR-3 decreased to 60?%, which revealed highly efficient chemotherapy. However, CPT loaded into HNP or HER-HNP had no significant effects on the viability of macrophages. Judging from these data, HER-HNPs are very suitable for application in anticancer therapy. A HER-HNP-CPT drug delivery system offers a new direction for a hydrophobic anticancer drug carrier and can be expanded to practical applications with further studies.     

Evaluation the synergistic antitumor effect of methotrexate–camptothecin codelivery prodrug from self-assembly process to acid-catalyzed both drugs release: A comprehensive theoretical study

Therapeutic efficiency of amphiphilic methotrexate–camptothecin (MTX-CPT) prodrug compared to free drug mixture (MTX/CPT) has been investigated using all-atom molecular dynamics simulation and first principles density functional theory calculations. This comparison revealed that MTX–CPT prodrug tends to form spherical self-assembled nanoparticle (NP), while free MTX/CPT mixture forms rod-shape NP. These observations are attributed to a structural defect in the MTX–CPT prodrug and solvation free energies of MTX, CPT and MTX-CPT molecules. The results provided evidence that noncovalent interactions (NCIs) among the pharmaceutical drugs play a very important role in anticancer agents aggregation process, leading to enhanced stability of the self-assembled NPs. It is found that the stability of MTX–CPT self-assembled NP is greater than the MTX/CPT NP due to the synergistic effect of hydrogen bonding between monomers and solvent (water). Moreover, the noncatalyzed as well as catalyzed hydrolysis reactions of MTX–CPT prodrug are theoretically studied at the PCM(water)//M06-2X/6−31G(d,p) computational level to shed additional light on the role of acidic condition in tumor tissues. We found that the ester hydrolysis in mild acidic solutions is a concerted reaction. In an agreement between theory and experiment, we also confirmed that the activation energies of the catalyzed-hydrolysis steps are much lower than the activation energies of the corresponding steps in the noncatalyzed reaction. Thus, the MTX–CPT prodrug reveals very promising properties as a pH-controlled drug delivery system.     

Injectable Graphene Oxide/Graphene Composite Supramolecular Hydrogel for Delivery of Anti-Cancer Drugs

Injectable hydrogels have attracted a lot of attention in drug delivery, however, their capacity to deliver water-insoluble or hydrophobic anti-cancer drugs is limited. Here, we developed injectable graphene oxide/graphene composite supramolecular hydrogels to deliver anti-cancer drugs. Pluronic F-127 was used to stabilize graphene oxide (GO) and reduced graphene oxide (RGO) in solution, which was mixed with α-cyclodextrin (α-CD) solution to form hydrogels. Native hydrogel was used as control. GO or RGO slightly shortened gelation time. The storage and loss moduli of the hydrogels were tracked by dynamic force measurement. The storage modulus of GO or RGO composite hydrogels was larger than that of the native hydrogel. Hydrogels were unstable in solution and eroded gradually. GO or RGO in Pluronic F-127 solution could potentially improve the solubility of the water-insoluble anti-cancer drug camptothecin (CPT), especially with large drug-loaded CPT amount. Drug release behaviors from solutions and hydrogels were characterized. The nanocomponents (GO or RGO) were able to bind more drug molecules either for CPT or for doxorubicin hydrochloride (DXR) in solution. Therefore, GO or RGO composite hydrogel could potentially enable better controlled and gentler drug release (for both CPT and DXR) than native hydrogel.     

聚乳酸-乙醇酸/纳米氧化锌复合电纺纤维装载亲疏水药物的控释及体外细胞毒性

利用静电纺丝技术制备了负载亲水性药物阿霉素(DOX)以及疏水性药物喜树碱(CPT)的复合纳米纤维. 先用巯基封端的普朗尼克(F127)修饰纳米氧化锌(FZnO), 再将FZnO负载盐酸阿霉素(DOX@FZnO), 最后将DOX@FZnO与CPT一起纺入聚乳酸-乙醇酸(PLGA)纤维中. 体外药物释放结果表明, 复合纳米纤维能够减小亲水性药物的突释, 减缓药物释放速率, 延长药物释放时间. 体外细胞活性结果表明, 双载药复合纤维比单载药复合纤维具有更强的细胞毒性, 能够有效抑制癌细胞生长.     

Functionalized carbon nanomaterials as nanocarriers for loading and delivery of a poorly water-soluble anticancer drug: a comparative study

Carbon nanomaterials such as multiwalled carbon nanotubes (MWCNTs) and graphene oxide (GO) have been functionalized by highly hydrophilic and biocompatible poly(vinyl alcohol) (PVA) for loading and delivery of an anticancer drug, camptothecin (CPT). For the first time, CPT was loaded onto MWCNT-PVA and GO-PVA through π-π interactions and its capability to kill human breast and skin cancer cells was investigated.     

The Self‐Assembly of Anticancer Camptothecin–Dipeptide Nanotubes: A Minimalistic and High Drug Loading Approach to Increased Efficacy

20‐(S)‐Camptothecin (CPT)‐conjugated dipeptides are reported that preassemble into nanotubes with diameters ranging from 80–120 nm. These nanoassemblies maintain a high (～47 %) drug loading and exhibit greater drug stability (i.e., resistance to lactone hydrolysis), and consequently greater efficacy against several human cancer cells (HT‐29, A549, H460, and H23) in vitro compared with the clinically used prodrug irinotecan. A key and defining feature of this system is the use of the CPT‐conjugated dipeptide as both the drug and precursor to the nanostructured carrier, which simplifies the overall fabrication process.     

Polymeric Nanoparticles with a Glutathione‐Sensitive Heterodimeric Multifunctional Prodrug for In Vivo Drug Monitoring and Synergistic Cancer Therapy

Polymeric micelle‐based drug delivery systems have dramatically improved the delivery of small molecular drugs, yet multiple challenges remain to be overcome. A polymeric nanomedicine has now been engineered that possesses an ultrahigh loading (59 %) of a glutathione (GSH)‐sensitive heterodimeric multifunctional prodrug (HDMP) to effectively co‐deliver two synergistic drugs to tumors. An HDMP comprising of chemotherapeutic camptothecin (CPT) and photosensitizer 2‐(1‐hexyloxyethyl)‐2‐devinyl pyropheophorbide‐α (HPPH) was conjugated via a GSH‐cleavable linkage. The intrinsic fluorogenicity and label‐free radio‐chelation (⁶⁴Cu) of HPPH enabled direct drug monitoring by fluorescence imaging and positron emission tomography (PET). Through quantitative PET imaging, HDMP significantly improves drug delivery to tumors. The high synergistic therapeutic efficacy of HDMP‐loaded NPs highlights the rational design of HDMP, and presents exciting opportunities for polymer NP‐based drug delivery.     

Azobenzene Polyesters Used as Gate‐Like Scaffolds in Nanoscopic Hybrid Systems

The synthesis and characterisation of new capped silica mesoporous nanoparticles for on‐command delivery applications is reported. Functional capped hybrid systems consist of MCM‐41 nanoparticles functionalised on the external surface with polyesters bearing azobenzene derivatives and rhodamine B inside the mesopores. Two solid materials, Rh‐PAzo8‐S and Rh‐PAzo6‐S, containing two closely related polymers, PAzo8 and PAzo6, in the pore outlets have been prepared. Materials Rh‐PAzo8‐S and Rh‐PAzo6‐S showed an almost zero release in water due to steric hindrance imposed by the presence of anchored bulky polyesters, whereas a large delivery of the cargo was observed in the presence of an esterase enzyme due to the progressive hydrolysis of polyester chains. Moreover, nanoparticles Rh‐PAzo8‐S and Rh‐PAzo6‐S were used to study the controlled release of the dye in intracellular media. Nanoparticles were not toxic for HeLa cells and endocytosis‐mediated cell internalisation was confirmed by confocal microscopy. Furthermore, the possible use of capped materials as a drug‐delivery system was demonstrated by the preparation of a new mesoporous silica nanoparticle functionalised with PAzo6 and loaded with the cytotoxic drug camptothecin (CPT‐PAzo6‐S). Following cell internalisation and lysosome resident enzyme‐dependent gate opening, CPT‐PAzo6‐S induced CPT‐dependent cell death in HeLa cells.     

Preparation and Cellular Uptake of pH‐Dependent Fluorescent Single‐Wall Carbon Nanotubes

Fluorescent single‐wall carbon nanotubes (SWCNTs) were prepared by mixing cut SWCNTs with acridine orange (AO). The optical absorbance and fluorescence characteristics of AO–SWCNT conjugates display interesting pH‐dependent properties. Fluorescence microscopy in combination with transmission electron microscopy proves that AO–SWCNTs can enter HeLa cells and are located inside lysosomes. The endocytosis‐inhibiting tests show that the clathrin‐mediated endocytosis is a key step in the internalization process. The internalized AO–SWCNTs remain inside lysosomes for more than a week and have little effect on cell proliferation. These findings may be useful in understanding the SWCNT‐based intracellular drug delivery mechanism and help to develop new intracellular drug transporters.     

Single‐Particle Tracking and Modulation of Cell Entry Pathways of a Tetrahedral DNA Nanostructure in Live Cells

DNA is typically impermeable to the plasma membrane due to its polyanionic nature. Interestingly, several different DNA nanostructures can be readily taken up by cells in the absence of transfection agents, which suggests new opportunities for constructing intelligent cargo delivery systems from these biocompatible, nonviral DNA nanocarriers. However, the underlying mechanism of entry of the DNA nanostructures into the cells remains unknown. Herein, we investigated the endocytotic internalization and subsequent transport of tetrahedral DNA nanostructures (TDNs) by mammalian cells through single‐particle tracking. We found that the TDNs were rapidly internalized by a caveolin‐dependent pathway. After endocytosis, the TDNs were transported to the lysosomes in a highly ordered, microtubule‐dependent manner. Although the TDNs retained their structural integrity within cells over long time periods, their localization in the lysosomes precludes their use as effective delivery agents. To modulate the cellular fate of the TDNs, we functionalized them with nuclear localization signals that directed their escape from the lysosomes and entry into the cellular nuclei. This study improves our understanding of the entry into cells and transport pathways of DNA nanostructures, and the results can be used as a basis for designing DNA‐nanostructure‐based drug delivery nanocarriers for targeted therapy.     

Enzyme‐Responsive Intracellular‐Controlled Release Using Silica Mesoporous Nanoparticles Capped with ε‐Poly‐L‐lysine

The synthesis and characterization of two new capped silica mesoporous nanoparticles for controlled delivery purposes are described. Capped hybrid systems consist of MCM‐41 nanoparticles functionalized on the outer surface with polymer ε‐poly‐L ‐lysine by two different anchoring strategies. In both cases, nanoparticles were loaded with model dye molecule [Ru(bipy)₃]²⁺. An anchoring strategy involved the random formation of urea bonds by the treatment of propyl isocyanate‐functionalized MCM‐41 nanoparticles with the lysine amino groups located on the ε‐poly‐L ‐lysine backbone (solid Ru‐rLys‐S1 ). The second strategy involved a specific attachment through the carboxyl terminus of the polypeptide with azidopropyl‐functionalized MCM‐41 nanoparticles (solid Ru‐tLys‐S1 ). Once synthesized, both nanoparticles showed a nearly zero cargo release in water due to the coverage of the nanoparticle surface by polymer ε‐poly‐L ‐lysine. In contrast, a remarkable payload delivery was observed in the presence of proteases due to the hydrolysis of the polymer’s amide bonds. Once chemically characterized, studies of the viability and the lysosomal enzyme‐controlled release of the dye in intracellular media were carried out. Finally, the possibility of using these materials as drug‐delivery systems was tested by preparing the corresponding ε‐poly‐L ‐lysine capped mesoporous silica nanoparticles loaded with cytotoxic drug camptothecin (CPT), CPT‐rLys‐S1 and CPT‐tLys‐S1 . Cellular uptake and cell‐death induction were studied. The efficiency of both nanoparticles as new potential platforms for cancer treatment was demonstrated.     

Incorporation methods for cholic acid chitosan-g-mPEG self-assembly micellar system containing camptothecin

A water-insoluble anticancer agent, camptothecin (CPT) was incorporated to a polymeric micelle carrier system preparing from cholic acid chitosan-grafted poly (ethylene glycol) methyl ether (CS-mPEG-CA). CS-mPEG-CA formed a core–shell micellar structure with a critical micelle concentration (CMC) of 7.08 μg/ml. Incorporation efficiency was investigated by varying physical incorporation method and initial drug loading. Among three incorporation methods (dialysis, emulsion and evaporation methods), an emulsion method showed the highest CPT incorporation efficiency. Increasing the initial CPT loading from 5 to 40%, the incorporation efficiency decreased. In all examined CPT-loaded CS-mPEG-CA micelles, 5% initial drug loading showed the highest drug incorporation efficiency. Release of CPT from the micelles was sustained when increasing the initial CPT loading. This indicates the importance of incorporation method and the initial drug loading to obtain the optimum particle size with high drug loading and sustained drug release. When compared to the unprotected CPT, CPT-loaded CS-mPEG-CA micelles were able to prevent the hydrolysis of the lactone group of the drug. This novel CS-mPEG-CA polymer presents considerable potential interest in the further development of CPT carrier.     

Macrophage‐Targeted Isoniazid–Selenium Nanoparticles Promote Antimicrobial Immunity and Synergize Bactericidal Destruction of Tuberculosis Bacilli

Pathogenesis hallmarks for tuberculosis (TB) are the Mycobacterium tuberculosis (Mtb) escape from phagolysosomal destruction and limited drug delivery into infected cells. Several nanomaterials can be entrapped in lysosomes, but the development of functional nanomaterials to promote phagolysosomal Mtb clearance remains a big challenge. Here, we report on the bactericidal effects of selenium nanoparticles (Se NPs) against Mtb and further introduce a novel nanomaterial‐assisted anti‐TB strategy manipulating Ison@Man‐Se NPs for synergistic drug‐induced and phagolysosomal destruction of Mtb. Ison@Man‐Se NPs preferentially entered macrophages and accumulated in lysosomes releasing Isoniazid. Surprisingly, Ison@Man‐Se/Man‐Se NPs further promoted the fusion of Mtb into lysosomes for synergistic lysosomal and Isoniazid destruction of Mtb. Concurrently, Ison@Man‐Se/Man‐Se NPs also induced autophagy sequestration of Mtb, evolving into lysosome‐associated autophagosomal Mtb degradation linked to ROS‐mitochondrial and PI3K/Akt/mTOR signaling pathways. This novel nanomaterial‐assisted anti‐TB strategy manipulating antimicrobial immunity and Mtb clearance may potentially serve in more effective therapeutics against TB and drug‐resistant TB.     

Synthesis and Release Behavior of a Hybrid of Camptothecin Intercalated Dodecyl Sulfate Modified Layered Double Hydroxide

The intercalation of a non-ionic and poorly water-soluble drug,camptothecin（CPT）,into dodecyl sulfate （DS） modified layered double hydroxide（LDH） was carried out via a secondary intercalation method to obtain a CPT-DS-LDH hybrid.The in vitro CPT release eFxaminations from the hybrid show that the hybrid can well control the release of CPT,which indicates that the hybrid is a potential drug controlled-release system.Moreover,the intercalation kinetics of CPT into the DS modified LDH fits for the pseudo-second-order model.And the release kinetic process of CPT from the CPT-DS-LDH hybrid at pH=4.8 can be described with pseudo-first-order model,while that at pH=7.2 can be described with both pseudo-first-order model and pseudo-second-order model.Meanwhile,the release mechanism of CPT from the CPT-DS-LDH hybrid was discussed.     

Nanoparticles for Triple Drug Release for Combined Chemo- and Photodynamic Therapy

A pH-responsive drug delivery system (DDS) based on mesoporous silica nanoparticles (MSNs) has been prepared for the delivery of three anticancer drugs with different modes of action. The novelty of this system is its ability to combine synergistic chemotherapy and photodynamic therapy. A photoactive conjugate of a phthalocyanine (Pc) and a topoisomerase I inhibitor (topo-I), namely camptothecin (CPT), linked by a poly(ethylene glycol) (PEG) chain has been synthesized and then loaded into the mesopores of MSNs. Doxorubicin (DOX), which is a topoisomerase II inhibitor (topo-II), has also been covalently anchored to the outer surface of the MSNs through a dihydrazide PEG linker. In the acidic environment of tumor cells, selective release of the three drugs takes place. In vitro studies have demonstrated the endocytosis of the system into HeLa and HepG2 cells, and the subsequent release of the three drugs into the cytoplasm and nucleus. Furthermore, the cytotoxic effect of DOX, CPT and Pc has been assessed in vitro before and upon light irradiation.