Doxorubicin Conjugates Research Articles

Self-assembling Dextran prodrug for redox- and pH-responsive co-delivery of therapeutics in cancer cells

Self-assembling prodrug containing pH- and redox-responsive functional groups was prepared by covalent conjugation of Doxorubicin (Dox) and lipoic acid (LA) to a polyaldehyde Dextran (PAD). The resultant amphiphilic DoxPADLA forms, in a single step, hemocompatible vesicular systems able to respond to intracellular signals without using external crosslinking agents. Camptothecin (CPT) was encapsulated exploiting the hydrophobic interactions with the vesicle membrane, and release experiments, carried out in media mimicking the physiological and endolysosomial compartments, in the absence or presence of Glutathione, proved the ability of the system to modulate drug release in relation to the variation of pH and redox potential. Cytotoxicity assays and confocal experiments demonstrated the efficacy of the vesicle formulation in enhancing the synergistic anticancer effect of the delivered Dox and CPT and a rapid and significant internalization of the carrier in cancer cells.

Design, synthesis, and in vitro antitumor activity of a transferrin receptor-targeted peptide-doxorubicin conjugate.

In this study, a peptide-drug conjugate was designed and synthesized by connecting a transferrin receptor (TfR)-targeted binding peptide analog BP9a (CAHLHNRS) with doxorubicin (DOX) through N-succinimidyl-3-maleimidopropionate (SMP) as the cross-linker. Confocal laser scanning microscopy results indicated that free DOX mainly accumulated in the nuclei of both TfR overexpressed HepG2 hepatoma cells and L-O2 normal liver cells expressing low level of TfR; most of the BP9a-DOX conjugate displayed cytoplasmic location, and its cellular uptake by HepG2 cells was obviously reduced by TfR blockage test. Nevertheless, the cellular uptake of this conjugate by L-O2 cells was much less than that of free DOX. Meanwhile, the BP9a-DOX conjugate exhibited lower in vitro antiproliferative activity against HepG2 cells than free DOX, but its cytotoxic effect on L-O2 cells was decreased compared with that of free DOX. These results suggest that BP9a could be applied as a potential TfR-targeted peptide vector for selective drug delivery.

Synthesis and anticancer effects of conjugates of doxorubicin and unsaturated fatty acids (LNA and DHA)

Doxorubicin (DOX) is a leading cytostatic drug with many adverse effects in use. We are still looking for methods that will allow us to preserve the therapeutic effect against the tumor cells and reduce the toxicity to the normal cells. In our work, we obtained amide derivatives of DOX by reaction of the amino group with α-linolenic (LNA) and docosahexaenoic (DHA) acids (2, 3), as well as double-substituted derivatives via amide and ester linkages (4, 5). The structures of the compounds were confirmed by Proton Nuclear Magnetic Resonance (1H NMR), Carbon-13 Nuclear Magnetic Resonance (13C NMR), and High Resolution Mass Spectrometry (HRMS) analyses. For all compounds 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the cytotoxic effect on human cancer cell lines (SW480, SW620, and PC3) and Chinese hamster lung fibroblasts (V79) that were used as a control. The cytotoxic activity was established by calculation of the inhibitory concentration IC50. In addition, a cytotoxic capacity against tumor cells for tested compounds was expressed as a selectivity factor (selectivity index, SI). Lactate dehydrogenase (LDH) assay was performed for all compounds to assess the level of cell damage. To explain the basic mechanism of cell death induction the Annexin V-FITC/IP flow cytometry analysis was investigated. We found that all studied conjugates exhibit lower cytotoxicity but higher selectivity than DOX. Among the all derivatives, the conjugates formed by the amide and ester linkages (4, 5) were found to be more promising compared with conjugates (2, 3) formed only by the amide linkage. They show high cytotoxicity toward the tumor cell lines and moderate cytotoxicity towards the normal cell line.

Combination of Doxorubicin with Gemcitabine-Incorporated G-Quadruplex Aptamer Showed Synergistic and Selective Anticancer Effect in Breast Cancer Cells.

Doxorubicin (DOX) is one of the most effective anticancer agents used for the treatment of multiple cancers; however, its use is limited by its short half-life and adverse drug reactions, especially cardiotoxicity. In this study, we found that the conjugate of DOX with APTA12 (Gemcitabine incorporated G-quadruplex aptamer) was significantly more cancer selective and cytotoxic than DOX. The conjugate had an affinity for nucleolin, with higher uptake and retention into the cancer cells than those of DOX. Further, it was localized to the nucleus, which is the target site of DOX. Owing to its mechanism of action, DOX has the ability to intercalate into the nucleotides thus making it a suitable drug to form a conjugate with cancer selective aptamers such as APTA12. The conjugation can lead to selectively accumulate in the cancer cells thus decreasing its potential nonspecific as well as cardiotoxic side effects. The aim of this study was to prepare a conjugate of DOX with APTA12 and assess the chemotherapeutic properties of the conjugate specific to cancer cells. The DOX-APTA12 conjugate was prepared by incubation and its cytotoxicity in MCF-10A (non-cancerous mammary cells) and MDA-MB-231 (breast cancer cells) was assessed. The results indicate that DOX-APTA12 conjugate is a potential option for chemotherapy especially for nucleolin expressing breast cancer with reduced doxorubicin associated side effects.

Construction of doxorubicin-conjugated lentinan nanoparticles for enhancing the cytotoxocity effects against breast cancer cells

Lentinan(LNT) has many kinds of pharmacological activities such as antioxidative activities, hypoglycemic effect, anti-hyperlipidemic effect and so on. Here, LNT was used as the skeleton material to couple with doxorubicin(DOX) by forming the LNT–DOX conjugates in order to enhance anticancer effects and reduce the systemic side effects of DOX. Based on the screening results, we observed that LNT can acted as an antitumor carrier for release of DOX with pH-responsive. DOX release from conjugates was 63.1% at pH 5.0 for up to 48 h, whereas 13.6% of DOX release was observed at pH 7.4 in phosphate buffered saline. The grafting rate of LNT-DOX conjugates was 6.5±0.65 mg/100 mg DOX content. The morphology results showed that LNT-DOX conjugates were considerably more amorphous than LNT. LNT linked by DOX basically maintained the original structure and rheology in water solution. The in vitro anticancer activity of LNT–DOX conjugates was higher than that of free DOX. It is important that LNT–DOX conjugates can enhance anticancer effects in breast cancer cells and decrease the cytotoxocity effects against human normal cells. This work proved that the LNT–DOX conjugates might be suitable for building anticancer drug platform in the course of chemotherapy.

Abstract 2091: Lysosomal targeting of doxorubicin induces different membrane permeabilization and cytotoxicity in two breast cancer cell lines

Abstract Background: Lysosomal targeting has been investigated for the treatment of cancer but details of the resulting cytotoxicity remain unclear. The induced lysosomal membrane permeabilization (LMP) has been shown to induce apoptosis and cytotoxicity. The purpose of this study is to elucidate details of doxorubicin (DOX) induced LMP in breast cancer cells and identify correlations with cytotoxicity. Methods: A gelatin – doxorubicin conjugate (GDOX) to target lysosomes was synthesized by EDC chemistry in formamide and purified by precipitation and desalting. GDox and free Dox uptake studies at 10 µM or its equivalent were conducted in MCF7 and MDA-MB-231 (triple negative breast cancer-TNBC) cells in growth media. Intracellular localization was followed by fluorescent markers. LMP was shown by cytosolic release of 10 kD Dextran-Alexa Fluor 488 previously loaded into lysosomes. Intra-lysosomal release of Dox from GDOX was examined by rupture of lysosomes and nuclear accumulation of released Dox followed by fluorescent microscopy and ImageJ. Released Dox accumulation in the nucleus without lysosome rupture was analyzed by UHPLC. Viability, growth inhibition profiles, and IC50 values were determined by the MTT procedure and GraphPad Prism 7. Results: GDox localized substantially to the lysosomes in both MCF7 and TNBC cells while free DOX localized to the nucleus, as expected. GDOX induced LMP by 24 hrs in 100% of the TNBC cells but only 20% of the MCF7 cells even up to 48 hrs. Intra-lysosomal DOX release in the MCF7 cells was notable only by 24 hrs and was estimated by fluorescent intensity (300,000 integrated density units per cell) at one-half the amount of free DOX accumulation in the nucleus. Nuclear accumulation of released DOX escaping intact lysosomes in MCF7 cells by 24 hrs was one-half that at 48 hrs which reached 0.13 µg Dox per 106 cells by 48 hrs representing only one-tenth that achieved by free DOX. MCF7 cell viability in GDOX was reduced to 62±3% of controls by 24 hr but reached 19±4% by 48 hrs compared to 11±1% for free Dox. The IC50 values of GDOX after 48 hr were 1.3±0.7 µM and 4.5±2 µM in TNBC and MCF7 cells, respectively. Conclusions: Taken together these results indicate that LMP is not induced by pooling of released DOX in MCF7 lysosomes nor does LMP contribute to cytotoxicity in these cells. The lysosomal accumulation of GDOX in MDA cells, in contrast to MCF7 cells, leads to extensive LMP which may contribute to the greater cytotoxicity in these cells compared to the MCF7 cells. The small amount of released DOX accumulating in the MCF7 nuclei may induce a nuclear pathway of cytotoxicity in these cells. Acknowledgements: Financial support is appreciated from the Agnes Varis Trust for Women’s Leadership and Health, King Abdul-Aziz University, and NIH R15 CA135421. Citation Format: Mohammed Alvi, Rachel Nicoletto, Bayan A. Eshmawi, Clyde M. Ofner. Lysosomal targeting of doxorubicin induces different membrane permeabilization and cytotoxicity in two breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2091.

Abstract 2169: Doxorubicin conjugation to reovirus enhances tumor cell-directed oncolysis

Abstract Breast cancer remains the most diagnosed type of cancer and second leading cause of cancer-related deaths in women in the United States. Triple-negative breast cancer (TNBC) constitutes 10-20% of breast cancer cases. TNBCs are characterized by lack of estrogen (ER) and progesterone (PR) receptors and growth factor receptor HER2/Neu on the cell surface. Therapies that target ER, PR, or HER2 are thus ineffective against TNBC. TNBC is primarily treated with cytotoxic chemotherapy or radiation therapy, which can cause significant damage to healthy cells and tissue. Therefore, there is need for therapies that selectively kill TNBC cells with reduced off-tumor effects. The concept of oncolytic virotherapy has existed since the early 1900s. However, oncolytic viruses have limited efficacy as single agents. Mammalian orthoreovirus (reovirus) is a non-enveloped, segmented double-stranded RNA virus with tropism for transformed cells. Reovirus is in Phase I - III clinical trials to test its oncolytic efficacy against a variety of cancers. Success has been limited and few trials have tested reovirus against breast cancer. In a high-throughput screen of small molecule inhibitors, we identified the topoisomerase II inhibitor doxorubicin hydrochloride (dox) as an enhancer of reovirus infectivity in the TNBC cell line MDA-MB-231. To better control dox delivery and enhance reovirus oncolytic potential, we chemically conjugated dox to reovirus virions (reo-dox). While reo-dox attachment to MDA-MB-231 cells is slightly impaired, viral replication is largely unaffected. Infection of MDA-MB-231 cells with reo-dox resulted in increased cytopathicity and faster induction of cell death than virus alone. MDA-MB-231 cells infected with reo-dox, but not virus alone, induced DNA double-strand breaks and activation of DNA damage response. Together, our findings show that reo-dox exhibits superior toxicity in TNBC cells than virus alone. Future studies will define the mechanism of enhanced cytopathicity of reo-dox and oncolytic efficacy of dox-conjugated reovirus in vivo. Delivery of small molecule inhibitors via conjugation to reovirus particles may provide an effective new method to directly target and kill cancer cells while minimizing toxicity to healthy cells and tissues. Citation Format: Jameson T. Berry, Bernardo A. Mainou. Doxorubicin conjugation to reovirus enhances tumor cell-directed oncolysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2169.

PH-responsive and self-targeting assembly from hyaluronic acid-based conjugate toward all-in-one chemo-photodynamic therapy

Chemo-photodynamic therapy is an attractive strategy against cancer. However, the combination of chemotherapeutic agent and photosensitizer is usually realized by physically embedding one or two agents in the carriers. In this case, batch to batch variation of drug contents increases the risk of composition uncertainty, limiting the clinical application of currently developed chemo-photodynamic therapy. Therefore, it is highly desirable for constructing chemo-photodynamic therapy nanoplatform with precisely controllable composition and drug loading content. Here, a precise chemo-photodynamic therapy nanoplatform is reported based on the chemical conjugation of both doxorubicin (DOX) and photosensitizer chlorin e6 (Ce6) to active targeting hyaluronic acid (HA). The achieved HA-DOX-Ce6 (HDC) conjugate can self-assemble into all-in-one nanoparticles (NPs) with properties of pH-response, self-targeting delivery, near-infrared (NIR) fluorescence imaging and chemo-photodynamic combination therapy. Because HDC conjugate holds precise components, the HDC NPs have a constant composition and drug loading content, endowing a precise chemo-photodynamic therapy nanoplatform. The HDC NPs show significantly higher cellular uptake and remarkably better tumor-targeted accumulation than free drugs. Moreover, HDC NPs with the laser irradiation exhibit enhanced anticancer activities both in vitro and in vivo. This work may open the door for design of all-in-one advanced nanoplatform toward chemo-photodynamic therapy with precisely controllable composition and drug loading content.

Enzyme and pH dual-responsive hyaluronic acid nanoparticles mediated combination of photodynamic therapy and chemotherapy.

Hyaluronic acid (HA) is a natural biopolymer that can target to tumor cells due to CD44 receptors overexpressed in tumor cells. Here, a theranostic nanoparticle HA-Ce6 (DOX) with enzyme and pH dual-responsive is presented, which combined HA and a highly promised photosensitizer chlorin e6 (Ce6) using adipic dihydrazide (ADH) as a linker. The hydrazide group on its surface can efficiently conjugate doxorubicin to form HA-Ce6 (DOX) nanoparticles through the pH-sensitive hydrazone bond. In this study, the dual-response of HA-Ce6 (DOX) nanoparticles in the tumor cell are discussed. The HA-Ce6 (DOX) nanoparticles showed an average size of 90 nm with a uniform spherical morphology. In vitro drug release studies showed that HA-Ce6 (DOX) accomplished rapid drug release under acid conditions and enzyme stimulating. Confocal images revealed that the nanoparticles enhance the cellular accumulation of DOX and Ce6 in A549 cells. The therapeutic efficacy of HA-Ce6 (DOX) nanoparticles in A549 cells in vitro was evaluated through the MTT assay. The results showed that the therapeutic efficacy of HA-Ce6 (DOX) nanoparticles against A549 cells was remarkably enhanced compared with free DOX and free Ce6. These results indicate that the HA-Ce6 (DOX) nanoparticles could be a promising delivery system for photodynamic therapy and chemotherapy.

Polymeric prodrug microspheres with tumor intracellular microenvironment bioreducible degradation, pH-triggered "off-on" fluorescence and drug release for precise imaging-guided diagnosis and chemotherapy.

Theranostic nanoplatforms have been recognized for imaging-guided diagnosis and chemotherapy of cancer by integrating imaging function into the drug delivery systems (DDSs). Here, a facile approach was developed for the fabrication of polymeric prodrug microspheres by introducing pH sensitive "off-on" fluorochrome Rhodamine 6G into bioreducible cleavable bisulfide crosslinked PEGylated poly(glycidyl methacrylate) (PEG-PGMA) microspheres, followed with chemical conjugation of doxorubicin (DOX) via an acid-labile hydrazone linkage. High drug content of 25.4% was achieved for the final PEG-PGMA-Hy-DOX prodrug microspheres with average hydrodynamic diameter of 332 nm. The in vitro controlled release showed leakage-free in physiological medium but a sustained drug release up to 58% within 56 h in tumor intracellular microenvironment. The cellular experiments showed that the PEG-PGMA-Hy-DOX prodrug microspheres could be effectively internalized into HepG2 cells with enhanced anti-tumor efficacy than the free DOX. Furthermore, they showed fluorescence only in tumor intracellular microenvironment, indicating their promising potential for precise imaging-guided diagnosis and chemotherapy.

Sonodynamic Therapeutic Effects of Sonosensitizers with Different Intracellular Distribution Delivered by Hollow Nanocapsules Exhibiting Cytosol Specific Release.

Sonodynamic therapy (SDT) is a novel promising noninvasive therapy involving utilization of low-intensity ultrasound and sonosensitizer, which can generate reactive oxygen species (ROS) by sonication. In SDT, a high therapeutic effect is achieved by intracellular delivery and accumulation at the target sites of sonosensitizer followed by oxidative damage of produced ROS by sonication. Here, pH- and redox-responsive hollow nanocapsules are prepared through the introduction of disulfide cross-linkages to self-assembled polymer vesicles formed from polyamidoamine dendron-poly(l-lysine) for the efficient delivery of sonosensitizer. As sonosensitizer, doxorubicin (DOX), an anticancer drug accumulating into cell nucleus, is selected. Also, the conjugate of DOX and triphenylphosphonium (TPP-DOX) is synthesized as sonosensitizer with mitochondrial targeting ability. DOX and TPP-DOX are delivered to nucleus and mitochondria by nanocapsules. Furthermore, DOX- or TPP-DOX-loaded nanocapsules exhibit in vitro sonodynamic therapeutic effect to HeLa cells with sonication, which might be through oxidative damage to nucleus and mitochondria.

Synthesis of Doxorubicin and miRNA Stimuli-Sensitive Conjugates for Combination Therapy.

Recent advances in combination therapy by using chemotherapeutic drugs and small noncoding RNAs have highlighted the need for optimization of such agents to allow their carriage in a single delivery system. This protocol details the synthesis of a doxorubicin prodrug, where a NHS coupling reaction was used to sensitize the drug to the proteolytic activity of tumor microenvironments. The design of a lipid-modified miRNA by an S-S coupling reaction is also described. Modification of both, doxorubicin and miRNA, facilitated their simultaneous incorporation into mixed micelles for use in combination therapy against tumor cells.

Design, postpolymerization conjugation and self-assembly of a di-block copolymer-based prodrug for tumor intracellular acid-triggered DOX release.

A novel di-block copolymer-based prodrug was designed by atom transfer radical polymerization (ATRP) of glycidyl methacrylate (GMA) with a polyethylene glycol-based initiator (PEG-Br), postpolymerization aldehyde-modification, and doxorubicin (DOX) conjugation via an acid-labile imine bond. The polyprodrug could self-assemble into core-shell structured nanoparticles with the PEG block as the hydrophilic shell and the DOX-containing block as the hydrophobic core. The longer hydrophobic block resulted in a higher drug content but a bigger particle size, although all the four polyprodrug nanoparticles showed excellent fast pH-triggered DOX release owing to the auto-acceleration mechanism because of the transformation from the hydrophobic to semi-hydrophobic block during DOX release, with a cumulative release of >79% in the simulated tumor microenvironment within 12 h and a premature drug leakage of <14%. So the PEG-P(GMA-CBA)51-DOX polyprodrug with a middle hydrophobic block length was optimized as a promising drug delivery system (DDS), with a hydrodynamic diameter around 250 nm and a high DOX content of 30.35%. The in vitro cellular experiments indicated that the PEG-P(GMA-CBA)51-DOX polyprodrug nanoparticles could efficiently deliver DOX into the cell nuclei and show an enhanced anti-tumor efficacy on the HepG2 cells compared to the free DOX.

Co-assembled supramolecular hydrogels of doxorubicin and indomethacin-derived peptide conjugates for synergistic inhibition of cancer cell growth.

Conjugation of indomethacin with a self-assembling peptide moiety affords co-assembled supramolecular nanostructures of doxorubicin and peptide derivatives for tunable release of two drugs and synergistic effects against cancer cells, which illustrates a simple and effective approach to utilize co-assembled nanostructures for co-delivery of self-complementary drug pairs.

Transformable nanotherapeutics enabled by ICG: towards enhanced tumor penetration under NIR light irradiation.

Tumor penetration is the bottleneck for current cancer nanomedicine, limiting the ultimate antitumor efficacy in the clinic. Herein, by exploiting the well-known instability of indocyanine green (ICG), we report the preparation of near infrared (NIR) light responsive nanoparticles (NP) for enhanced tumor penetration. ICG crosslinks hydroxyethyl starch (HES) and doxorubicin (DOX) conjugates (HES-SS-DOX) via noncovalent interactions, facilitating the formation of ICG@HES-SS-DOX NP. The light triggered degradation of ICG leads to the dissociation of such NP, and the resulting HES-SS-DOX has been shown to penetrate deeper in both H22 tumor spheroids and tumor bearing mice, due to the photothermal effect of ICG. Therefore, the disintegrable ICG@HES-SS-DOX NP have better tumor penetration capacity than their counterparts, which originally cannot dissociate under NIR light stimulation. The reported ICG@HES-SS-DOX NP might be potent in treating malignant tumors with dense extracellular matrices, such as liver and pancreatic cancers. This study opens up a novel functionality of FDA-approved ICG for cancer nanotherapeutics.

Type of pH sensitive linker reveals different time-dependent intracellular localization, in vitro and in vivo efficiency in alpha-fetoprotein receptor targeted doxorubicin conjugate

Despite the presence of a variety of modern anticancer drugs at the market, doxorubicin (Dox) is still widely used in antineoplastic therapy, although its administration causes severe side effects. To enhance specific activity of such molecules, various approaches have been exploited: targeted moieties like monoclonal antibodies, onco-specific proteins and peptides are utilized as specific vector molecules; environment sensitive linkers are exploited to facilitate transported drug release at the target point etc. Acid-labile linkers are frequently used in synthesis due to the ability to be cleaved inside specific cellular compartments with acidic environment, avoiding possible recycling mechanisms. Two types of conjugates containing different acid-labile linkers have been synthesized. In vitro efficiency of doxorubicin conjugates with recombinant receptor-binding domain of human alpha-fetoprotein (3dAFPpG) synthesized with use of cis-aconitic anhydride (CAA) and linker based on succinimidyl 3-(2-pyridyldithio)propionate (SPDP) and 3-(2-pyridyldithio)propionic acid hydrazide (PDPH) was compared. The 3dAFPpG-SPDP-PDPH-Dox revealed a comparable with unmodified doxorubicin cytotoxic effect against the Dox sensitive MCF7 cell line and greater cytotoxicity against the anthracycline resistant MCF7Adr cells. Meanwhile the 3dAFPpG-CAA-Dox cytotoxic effect was significantly lower, although doxorubicin’s pH-dependent release profiles and intracellular accumulation rates were similar. These differences in cytotoxic activity were arguably explained by the dissimilarities in intracellular doxorubicin localization, which may originate from thiol reductase activity in lysosomes and late endosomes.

Polymer Cancerostatics Targeted by Recombinant Antibody Fragments to GD2-Positive Tumor Cells

A water-soluble polymer cancerostatic actively targeted against cancer cells expressing a disialoganglioside antigen GD2 was designed, synthesized and characterized. A polymer conjugate of an antitumor drug doxorubicin with a N-(2-hydroxypropyl)methacrylamide-based copolymer was specifically targeted against GD2 antigen-positive tumor cells using a recombinant single chain fragment (scFv) of an anti-GD2 monoclonal antibody. The targeting protein ligand was attached to the polymer-drug conjugate either via a covalent bond between the amino groups of the protein using a traditional nonspecific aminolytic reaction with a reactive polymer precursor or via a noncovalent but highly specific interaction between bungarotoxin covalently linked to the polymer and the recombinant scFv modified with a C-terminal bungarotoxin-binding peptide. The GD2 antigen binding activity and GD2-specific cytotoxicity of the targeted noncovalent polymer-scFv complex proved to be superior to the covalent polymer-scFv conjugate.

Iron oxide-pluronic F127 polymer nanocomposites as carriers for a doxorubicin drug delivery system

A multifunctional magnetic drug delivery system made up of an iron oxide nanoparticles (IONPs) core and a Pluronic F127 shell to carry Doxorubicin (DOX) was developed for neuroblastoma treatment. Several analytical techniques were then conducted to characterize the components of this system. The results showed that the prepared nanoparticles were nearly spherical ultrafine particles of 10–30 nm in diameter. Cryo–TEM images revealed the formation of a core-shell structure with different polydispersities and particle number densities. The hydrodynamic radius of the nanoparticles increased with increasing polymer concentration. The spectra of IONPs showed Fe2p and O1 s peaks at 700 and 530 eV, respectively, with binding energies associated with magnetite. The XANES spectra of the Fe atom in the different samples demonstrated an absorbance feature (Fe = 7112 eV) of a 1s to 3d transition. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) results proved that the prepared nanocarriers were nontoxic when tested on BE–2–M17 cells. Moreover, the UV–vis spectra of DOX confirmed the successful conjugation of DOX with F127–IONPs. The in vitro drug release profile showed that the drug release from the F127–IONPs was pH sensitive, with a faster DOX release rate in acidic conditions than in a neutral environment.

Biosynthesis of flower-shaped Au nanoclusters with EGCG and their application for drug delivery

BackgroundIn the last decade, the biosynthesis of metal nanoparticles using organisms have received more and more considerations. However, the complex composition of organisms adds up to a great barrier for the characterization of biomolecules involved in the synthesis process and their biological mechanisms.ResultsIn this research, we biosynthesized a kind of flower-shaped Au nanoclusters (Au NCs) using one definite component—epigallocatechin gallate (EGCG), which was the main biomolecules of green tea polyphenols. Possessing good stability for 6 weeks and a size of 50 nm, the Au NCs might be a successful candidate for drug delivery. Hence, both methotrexate (MTX) and doxorubicin (DOX) were conjugated to the Au NCs through a bridge of cysteine (Cys). The introduction of MTX provided good targeting property for the Au NCs, and the conjugation of DOX provided good synergistic effect. Then, a novel kind of dual-drug loaded, tumor-targeted and highly efficient drug delivery system (Au-Cys-MTX/DOX NCs) for combination therapy was successfully prepared. The TEM of HeLa cells incubated with Au-Cys-MTX/DOX NCs indicated that the Au-Cys-MTX/DOX NCs could indeed enter and kill cancer cells. The Au-Cys-MTX/DOX NCs also possessed good targeting effect to the FA-receptors-overpressed cancer cells both in vitro and in vivo. Importantly, the Au-Cys-MTX/DOX NCs resulted in an excellent anticancer activity in vivo with negligible side effects.ConclusionsThese results suggest that the biosynthesized Au-Cys-MTX/DOX NCs could be a potential carrier with highly efficient anticancer properties for tumor-targeted drug delivery.

Real-time cell analysis of the cytotoxicity of a pH-responsive drug-delivery matrix based on mesoporous silica materials functionalized with ferrocenecarboxylic acid

During the past decade, accumulating studies have been conducted on the mesoporous silica materials as the matrix of controlled drug-delivery, in which the complicated post-synthesis procedures are often involved with the molecular design to achieve the efficacy. In this study, a simplified drug delivery system of anti-cancer drug of doxorubicin (DOX) based on mesoporous SBA-15 functionalized with ferrocenecarboxylic acid (FCA) was constructed. Through a combination of physicochemical characterizations, the presence of FCA that was anchored inside the pore wall of amine groups grafted SBA-15 exhibits electron-accessible behavior without affecting the intactness of composite material. The pH-responsive release of drug molecules was achieved through the conjugation of DOX with FCA in the interior channels of mesoporous composites, which also favors the more coverage of DOX. Furthermore, the real-time cell analysis was performed to monitor the release of DOX from the mesopores and resulting cytotoxicity of cancer cell of A549 was evaluated, which results in a calculated IC50 of 43.8 μg/ml (24 h). The constructed mesoporous FCA-SBA-15 composite material provides an integrated nanoplatform to exert controlled-delivery of anti-cancer drug molecules.