Adsorption Properties of Doxorubicin Hydrochloride onto Graphene Oxide: Equilibrium, Kinetic and Thermodynamic Studies

Graphene aerogel nanoparticles for in-situ loading/pH sensitive releasing anticancer drugs

Free polymer graphene aerogel nanoparticles (GA NPs) were synthesized by using reduction/aggregation of graphene oxide (GO) sheets in the presence of vitamin C (as a biocompatible reductant agent) at a low temperature (40 °C), followed by an effective sonication. Synthesis of GA NPs in doxorubicin hydrochloride (DOX)-containing solution results in the simultaneous synthesis and drug loading with higher performance (than that of the separately synthesized and loaded samples). To investigate the mechanism of loading and the capability of GA NPs in the loading of other drug structures, two groups of ionized (DOX, Amikacin sulfate and, d-glucosamine hydrochloride) and non-ionized (Paclitaxel (PTX)) drugs were examined. Furthermore, the relationship between the bipolar level of DOX solution (contributing to H-bonding of DOX and GO) and the amount of DOX loading was investigated. The DOX showed higher loading (>3 times) than PTX, as anticancer drugs. Since both DOX and PTX possess aromatic structures, the higher loading of DOX was assigned to its positive partial charge and ionized nature. Accordingly, other drugs (having positive partial charge and ionized nature, but no aromatic structure) such as Amikacin sulfate and d-glucosamine hydrochloride presented higher loading than PTX. These results indicated that although the π-π interactions induced by aromatic structures are important in drug loading, the electrostatic interaction of ionized drugs with GO (especially through H-bonding) is the dominant mechanism. DOX-loaded GANPs showed high pH-sensitive release (equivalent to the carrier weight) after 5 days, which can indicate benefits in tumor cell acidic microenvironments in-vivo.

Externally predictive quantum-mechanical models for the adsorption of aromatic organic compounds by graphene-oxide nanomaterials

Graphene oxide is most often chosen as an alternative to graphene in the applications of carbon-based nanomaterials where adsorption is the primary process. However, its adsorption properties are poorly understood. The existing reports on the adsorption mechanism of graphene oxide rely on the linear free-energy/solvation-energy relationship (LFER/LSER) models. This computational work explores the role of quantum mechanical descriptors in the adsorption of aromatic organic compounds by graphene-oxide. For this, externally predictive quantitative models based on quantum-mechanical descriptors are developed and compared with the existing LSERs for the prediction of adsorption coefficients of organic compounds at three different adsorbate concentrations. The predictivity of the models is assessed using an external prediction set of compounds not used for developing the models. Notably, the mean polarizability, but originating from the quantum mechanical exchange interactions (between electrons of parallel spin), is found to be the most significant factor in driving the adsorption on graphene oxide. The present work also proposes quantum-mechanical-LSER models based on a combination of quantum-mechanical and LSER descriptors, which are in fact found to be equally predictive as the existing LSERs. The quantum-mechanical models proposed in this work are further utilized for the prediction of adsorption coefficients of aliphatic compounds.

Folic acid-functionalized graphene oxide nanosheets via plasma etching as a platform to combine NIR anticancer phototherapy and targeted drug delivery

PEGylated graphene oxide (GO) has shown potential as NIR converting agent to produce local heat useful in breast cancer therapy, since its suitable photothermal conversion, high stability in physiological fluids, biocompatibility and huge specific surface. GO is an appealing nanomaterial for potential clinical applications combining drug delivery and photothermal therapy in a single nano-device capable of specifically targeting breast cancer cells. However, native GO sheets have large dimensions (0.5-5 μm) such that tumor accumulation after a systemic administration is usually precluded. Herein, we report a step-by-step synthesis of folic acid-functionalized PEGylated GO, henceforth named GO-PEG-Fol, with small size and narrow size distribution (∼30 ± 5 nm), and the ability of efficiently converting NIR light into heat. GO-PEG-Fol consists of a nano-GO sheet, obtained by fragmentation of GO by means of non-equilibrium plasma etching, fully functionalized with folic acid-terminated PEG₂₀₀₀ chains through amidic coupling and azide-alkyne click cycloaddition, which we showed as active targeting agents to selectively recognize breast cancer cells such as MCF7 and MDA-MB-231. The GO-PEG-Fol incorporated a high amount of doxorubicin hydrochloride (Doxo) (>33%) and behaves as NIR-light-activated heater capable of triggering sudden Doxo delivery inside cancer cells and localized hyperthermia, thus provoking efficient breast cancer death. The cytotoxic effect was found to be selective for breast cancer cells, being the IC₅₀ up to 12 times lower than that observed for healthy fibroblasts. This work established plasma etching as a cost-effective strategy to get functionalized nano-GO with a smart combination of properties such as small size, good photothermal efficiency and targeted cytotoxic effect, which make it a promising candidate as photothermal agent for the treatment of breast cancer.

Oxaliplatin-Biomimetic Magnetic Nanoparticle Assemblies for Colon Cancer-Targeted Chemotherapy: An In Vitro Study

Conventional chemotherapy against colorectal cancer (CRC), the third most common cancer in the world, includes oxaliplatin (Oxa) which induces serious unwanted side effects that limit the efficiency of treatment. Therefore, alternative therapeutic approaches are urgently required. In this work, biomimetic magnetic nanoparticles (BMNPs) mediated by MamC were coupled to Oxa to evaluate the potential of the Oxa-BMNP nanoassembly for directed local delivery of the drug as a proof of concept for the future development of targeted chemotherapy against CRC. Electrostatic interactions between Oxa and BMNPs trigger the formation of the nanoassembly and keep it stable at physiological pH. When the BMNPs become neutral at acidic pH values, the Oxa is released, and such a release is greatly potentiated by hyperthermia. The coupling of the drug with the BMNPs improves its toxicity to even higher levels than the soluble drug, probably because of the fast internalization of the nanoassembly by tumor cells through endocytosis. In addition, the BMNPs are cytocompatible and non-hemolytic, providing positive feedback as a proof of concept for the nanoassembly. Our study clearly demonstrates the applicability of Oxa-BMNP in colon cancer and offers a promising nanoassembly for targeted chemotherapy against this type of tumor.

Graphene and graphene-based nanocomposites used for antibiotics removal in water treatment: A review

Due to their extensive application in human and veterinary medicine, antibiotics have been found worldwide and studied as new pollutants in the aquatic environment. In order to remove such pollutants, adsorption and photocatalysis have attracted tremendous attention because of their great potential in antibiotics removal from aqueous solutions. Graphene, as a novel two-dimensional nanomaterial, possesses unique structure and physicochemical properties, which can be used to efficiently adsorb and photodegrade antibiotics. This review provides an overview of the adsorptive and catalytic properties of graphene, and recent advances in adsorption and photodegradation of antibiotics by graphene and its derivatives. The factors that affect the adsorption and photodegradation of antibiotics are reviewed and discussed. Furthermore, the underlying mechanisms of adsorption and photodegradation are summarized and analyzed. Meanwhile, statistical analysis is conducted based on the number of papers and the maximum adsorption and photodegradation ability on various antibiotics removal. Finally, some unsolved problems together with major challenges that exist in the fabrication and application of graphene-based nanocomposites and the development for antibiotics removal is also proposed. This work provides theoretical guidance for subsequent research in the field of adsorption and photocatalytic removal of antibiotics from aqueous solution, especially on influence factors and mechanisms aspects.

Hybridization of graphene oxide into nanogels to acquire higher photothermal effects for therapeutic delivery

Although the special architecture of two-dimensional (2D) nanomaterials endows them with unique properties, their poor colloidal stability remains a main bottleneck to fully exploit their applications in the biomedical field. Herein, this study aims to develop a simple and effective approach to in situ incorporate 2D graphene oxide (GO) nanoplatelets into a thermosensitive matrix to acquire hybrid nanogels with good stability and photothermal effect. In order to improve its stability, GO firstly underwent silanization to its surface with double bonds, followed by intercalation with N-isopropylacrylamide (NIPAM) in the presence of a disulfide-containing crosslinker via an emulsion method. Radical polymerization was then initiated to accelerate direct GO exfoliation in PNIPAM nanogels by forming covalent bonds between them. The well-dispersed GO nanopletlets in the nanogels not only displayed an enhanced photothermal effect, but also improved the encapsulation efficiency of an anticancer drug. The hybrid nanogels accelerate drug release under conditions mimicking the acidic/reducible solid tumor and intracellular microenvironments, most importantly, it can be further enhanced via remote photothermal treatment. The multifunctional nanogels potentiate their synergistic anticancer bioactivity as an ideal nanoplatform for cancer treatment.

Polydopamine-based Implantable Multifunctional Nanocarpet for Highly Efficient Photothermal-chemo Therapy

We report a design and fabricate multifunctional localized platform for cancer therapy. Multiple stimuli-responsive polydopamine (PDA) was used for surface modification of electrospun doxorubicin hydrochloride (DOX) loaded polycaprolactone (PCL) fibers to make a designated platform. Photothermal properties such as photothermal performance and stability of the resulting composite mats were studied under the irradiation of the near-infrared (NIR) laser of 808 nm. With the incorporation of PDA into the fiber, a remarkable increase of local temperature was recorded under NIR illumination in a concentration-dependent manner with excellent stability. Drug released assay results revealed PDA coated PCL-DOX mats showed pH and NIR dual responsive behavior thereby exhibiting improved drug release in an acidic medium compared to physiological pH condition (pH 7.4) which is further increased by NIR exposure. The cancer activity in vitro of the mats was evaluated using cell counting (CCK) and live and dead cell assays. The combined effect of NIR mediated hyperthermia and chemo release resulting improved cells death has been reported. In summary, this study presents a major step forward towards a therapeutic model to cancer treatment utilizing pH and NIR dual responsive property from PDA alone in a fibrous mat.

Intracellular Dynamic Disentangling of Doxorubicin Release from Luminescent Nanogold Carriers by Fluorescence Lifetime Imaging Microscopy (FLIM) under Two-Photon Excitation

There is still a lack of available techniques to follow noninvasively the intracellular processes as well to track or disentangle various signals from the therapeutic agents at the site of action in the target cells. We present here the assessment of the intracellular kinetics of doxorubicin (DOX) and gold nanoparticle (AuNP) carriers by mapping simultaneously fluorescence and photoluminescence signals by fluorescence lifetime imaging microscopy under two-photon excitation (TPE-FLIM). The new nano-chemotherapeutic system AuNPs@gelatin-hyd-DOX has been fabricated by DOX loading onto the surface of gelatin-biosynthesized AuNPs (AuNPs@gelatin) through a pH-sensitive hydrazone bond. The successful loading of DOX onto the AuNPs was studied by spectroscopic methods and steady-state fluorescence, and the nanosystem pH-responsive character was validated under simulated biological conditions at different pH values (i.e., pH 4.6, 5.3, and 7.4). Considering that the fluorescence lifetime of DOX molecules at a specific point in the cell is a reliable indicator of the discrimination of the different states of the drug in the internalization path, i.e., released versus loaded, the kinetics of AuNPs@gelatin-hyd-DOX cellular uptake and DOX release was compared to that of free DOX, resulting in two different drug internalization pathways. Finally, cell viability tests were conducted against NIH:OVCAR-3 cell line to prove the efficiency of our chemotherapeutic nanosystem. TPE-FLIM technique could be considered promising for noninvasive, high-resolution imaging of cells with improved capabilities over current one-photon-excited FLIM.

Polydopamine Modified Superparamagnetic Iron Oxide Nanoparticles as Multifunctional Nanocarrier for Targeted Prostate Cancer Treatment

Polydopamine (pDA)-modified iron oxide core-shell nanoparticles (IONPs) are developed and designed as nanovectors of drugs. Reactive quinone of pDA enhances the binding efficiency of various biomolecules for targeted delivery. Glutathione disulfide (GSSG), an abundant thiol species in the cytoplasm, was immobilized on the pDA-IONP surface. It serves as a cellular trigger to release the drug from the nanoparticles providing an efficient platform for the drug delivery system. Additionally, GSSG on the surface was further modified to form S-nitrosoglutathione that can act as nitric oxide (NO) donors. These NPs were fully characterized using a transmission electronic microscopy (TEM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), zeta potential, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and UV-vis spectroscopies. Doxorubicin (DOX) and docetaxel (DTX) are two anticancer drugs, which were loaded onto nanoparticles with respective loading efficiencies of 243 and 223 µmol/g of IONPs, calculated using TGA measurements. DOX release study, using UV-vis spectroscopy, showed a pH responsive behavior, making the elaborated nanocarrier a potential drug delivery system. (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H-tetrazolium (MTS) and apoptosis assays were performed on PC3 cell lines to evaluate the efficiency of the developed nanocarriers. These nanoparticles thus can prove their worth in cancer treatment on account of their easy access to the site and release of drug in response to changes to internal parameters such as pH, chemicals, etc.

Carbon Nanotubes as A High-Performance Platform for Target Delivery of Anticancer Quinones

BACKGROUND

In spite of considerable efforts of researchers the cancer deseases remain to be incurable and a percentage of cancer deseases in the structure of mortality increases every year. At that, high systemic toxicity of antitumor drugs hampers their effective use. Because of this fact, the development of nanosystems for targeted delivery of antitumor drugs is one of the leading problem in nanomedicine and nanopharmacy.

OBJECTIVE

To critically examine the modern strategies for carbon nanotubes (CNTs)-based delivery of anticancer quinones and to summarize the mechanisms which can provide high effectiveness and multifunctionality of the CNT-based quinone delivery platform.

RESULTS

Quinones, including anthracycline antibiotics - doxorubicin and daunorubicin, are among the most prospective group of natural and syntetic compounds which exhibit high antitumor activity against different type of tumors. In this review, we focus on the possibilities of using CNTs for targeted delivery of antitumor compounds with quinoid moiety which is ordinarily characterized by high specific interaction with DNA molecules. Quinones can be non-covalently adsorbed on CNT surface due to their aromatic structure and π-conjugated system of double bonds. The characteristic features of doxorubicine-CNT complex are high loading efficiency, pH-dependent release in acidic tumor microenviroment, enough stability in biological fluid. Different types of CNT functionalization, targeting strategies and designs for multifunctional CNT-based doxorubicine delivery platform are disscussed.

CONCLUSION

Nanosystems based on functionalized CNTs are very promising platform for quinone delivery resulting in significant enhancement of cancer treatment efficiency. Functionalization of CNTs with the polymeric shell, especially DNA-based shells, can provide the greatest affinity and mimicry with biological structures.

pH-Dependent Adsorption Release of Doxorubicin on MamC-Biomimetic Magnetite Nanoparticles

New biomimetic magnetite nanoparticles (hereafter BMNPs) with sizes larger than most common superparamagnetic nanoparticles were produced in the presence of the recombinant MamC protein from Magnetococcus marinus MC-1 and functionalized with doxorubicin (DOXO) intended as potential drug nanocarriers. Unlike inorganic magnetite nanoparticles, in BMNPs the MamC protein controls their size and morphology, providing them with magnetic properties consistent with a large magnetic moment per particle; moreover, it provides the nanoparticles with novel surface properties. BMNPs display the isoelectric point at pH 4.4, being strongly negatively charged at physiological pH (pH 7.4). This allows both (i) their functionalization with DOXO, which is positively charged at pH 7.4, and (ii) the stability of the DOXO-surface bond and DOXO release to be pH dependent and governed by electrostatic interactions. DOXO adsorption follows a Langmuir-Freundlich model, and the coupling of DOXO to BMNPs (binary biomimetic nanoparticles) is very stable at physiological pH (maximum release of 5% of the drug adsorbed). Conversely, when pH decreases, these electrostatic interactions weaken, and at pH 5, DOXO is released up to ∼35% of the amount initially adsorbed. The DOXO-BMNPs display cytotoxicity on the GTL-16 human gastric carcinoma cell line in a dose-dependent manner, reaching about ∼70% of mortality at the maximum amount tested, while the nonloaded BMNPs are fully cytocompatible. The present data suggest that BMNPs could be useful as potential drug nanocarriers with a drug adsorption-release governed by changes in local pH values.

Graphene Oxide as a Nanocarrier for Controlled Loading and Targeted Delivery of Typhonium giganteum Drugs

In this study, Typhonium giganteum containing dual-function nanofibers composed of poly(butylene carbonate), polylactic acid, and graphene oxide (PBC/PLA/GO) were successfully fabricated by electrospinning. The results from thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and Fourier-transform infrared spectroscopy (FTIR) indicate that no interactions occurred between PBC and PLA. The nanofiber microstructure upon which graphene oxide was evenly distributed was studied by scanning electron microscopy (SEM) and showed good silk properties. The nanofibers can be used as a drug carrier since loaded Typhonium giganteum fibers possess excellent biocompatibility. Such nanofibers are effective in inhibiting the proliferation of A549 lung cancer cells, and thus they have potential for replacing chemotherapy-based treatments of lung cancer. In addition, the PBC/PLA/GO nanofibers degrade in physiological and natural environments, which is an important feature when engineering tissues and environment-friendly materials.

Synthesis, structural and in-vitro characterization of β-cyclodextrin grafted L-phenylalanine functionalized graphene oxide nanocomposite: A versatile nanocarrier for pH-sensitive doxorubicin delivery

To enhance graphene stability, drug loading capacity and biocompatibility, β-cyclodextrin (β-CD) was grafted onto graphene oxide (GO) using L-plenylalanine (Phe) as a linker. The doxorubicin (DOX) loading efficiency and capacity of GO-Phe-CD were 78.7% and 85.2%, respectively. The cone shaped cavity of CD acts as a host for DOX loading through inclusion complex formation. The GO-Phe-CD nanocarrier showed higher release ratio of DOX in acidic milieu of cancer cells. In addition, general cytotoxicity of the nanocarriers was examined by MTT assay and trypan blue dye exclusion in MCF-7 cell lines. It was established that the MTT assay was not an appropriate technique for predicting the cytotoxicity of graphene based nanocarriers due to the spontaneous formation of MTT formazan by these materials; leading to a false high biocompatibility. According to the trypan blue experiment, the GO-Phe-CD had significant cytocompatibility, and the DOX-loaded GO-Phe-CD had outstanding killing capability to MCF-7 cells.

One-pot synthesis and lubricity of fluorescent carbon dots applied on PCL-PEG-PCL hydrogel

This work presents a method for one-pot synthesis of N-doped nanometer-size carbon dots, which can be assembled with thermosensitive poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) hydrogel to achieve slow-release lubricity. The typical property of this green production was studied by fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The photoluminescence of composite PCEC/CDs hydrogel and its released solutions were characterized by ultraviolet spectrum, and the rheological properties were tested by rotary rheometer. Tribological performance of the released solution from composite PCEC/CDs hydrogel was obtained to compare with PBS and pure CDs solution. The experimental results reveal that the CDs contain the chemical groups of N-H, C-OH/C-O-C and -COOH, etc. In addition, the diameter of the CDs is in the range of 6~8 nm. The phase transition behavior of PCEC/CDs hydrogel can be still kept and its viscoelasticity hydrogel is improved by approximatively 7%. Furthermore, friction coefficient of the released solution from composite PCEC/CDs hydrogel decreases by about 70% than that of PBS. Besides, the wear condition can be improved by a lubricating transfer film formed by released CDs. This novel strategy for slow-release application is valuable for drug delivery and bio-tribology.

Fluorescence properties of doxorubicin coupled carbon nanocarriers

The effect of graphene oxide (GO) and nanodiamond (ND) is investigated on the spectral properties of doxorubicin (DOX) fluorescence emissions in the form of (DOX+GO) and (DOX+ND) biomaterials. It is shown that carbon nanostructure additives lead to sensible blueshifts, due to their optical properties and surface functionality. The quenching coefficient K_ND is obtained to be K_ND=0.043  (μg/ml)^-1 and K_GO=0.342  (μg/ml)^-1 in DOX solutions. In general, Stern-Volmer attests that excited (DOX+GO) strongly quenches with respect to that of (DOX+ND) regarding its privileged bonding affinity.

Green synthesis of rifampicin-loaded copper nanoparticles with enhanced antimicrobial activity

The antimicrobial properties of copper and rifampicin-loaded copper nanoparticles were investigated using four strains: Staphylococcus aureus, Escherichia coli, Bacillus pumilis and Pseudomonas fluorescens. Spherical-shaped copper nanoparticles were synthesized via green reduction method from the peppermint extract. It was found that adsorption of rifampicin on the copper nanosurface enhances its biological activity and prevents the development of resistance. The interactions between rifampicin-copper nanoparticles and bacteria cells were monitored using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). It was proven that loaded with rifampicin copper nanoparticles were able to damage the S. aureus cell membrane and facilitate the bacteria biofilm matrix disintegration. Moreover, the DNA decomposition of S. aureus treated with copper and rifampicin-copper nanoparticles was confirmed by agarose gel electrophoresis. The results obtained indicate that adsorption of rifampicin on the copper nanoparticles surface might provide the reduction of antibiotic dosage and prevent its adverse side effects.

High efficient anti-cancer drug delivery systems using tea polyphenols reduced and functionalized graphene oxide

Targeted drug delivery is urgently needed for cancer therapy, and green synthesis is important for the biomedical use of drug delivery systems in the human body. In this work, we report two targeted delivery systems for anticancer drugs based on tea polyphenol functionalized and reduced graphene oxide (TPGs). The obtained TPGs demonstrated an efficient doxorubicin loading capacity as high as 3.430 × 106 mg g−1 and 3.932 × 104 mg g−1, and exhibited pH-triggered release. Furthermore, the kinetic models, adsorption isotherms, and possible loading mechanisms were investigated in details. Compared to TPG1 and free doxorubicin, TPG2 is biocompatible to normal cells even at high concentrations and promotes tumor cells death by delivering the doxorubicin mainly to the nuclei. These results were confirmed using cell viability tests and confocal laser microscopy. Moreover, apoptosis tests showed that the mechanism of cancer cell death induced by TPG1 and TPG2 might follow the similar mechanisms. Taken together, these results demonstrate that TPGs provide a multifunctional drug delivery system with a greater loading capacity and pH-sensitive drug release for enhanced cancer therapy. The high drug payload capability and enhanced antitumor efficacy demonstrate that we developed systems are promising for various biomedical applications and cancer therapy.

Fabrication of aqueous-based dual drug loaded silk fibroin electrospun nanofibers embedded with curcumin-loaded RSF nanospheres for drugs controlled release

This paper presents a new nanofabrication method for dual drug loaded regenerated silk fibroin (RSF) nanofibers, based on a simple, colloid-electrospinning technique.

Selective Activation of Anticancer Chemotherapy by Cancer-Associated Fibroblasts in the Tumor Microenvironment

Background

The tumor microenvironment has recently emerged as a new target of anticancer chemotherapy. Selective activation of anticancer chemotherapy in the tumor microenvironment would further reduce the toxicity of anticancer drugs toward normal tissues. Fibroblast activation protein (FAP) is known to be selectively overexpressed on cancer-associated fibroblasts (CAFs) in the tumor microenvironment. Here, we designed an anticancer chemotherapeutic system based on promelittin, a peptide toxin that is selectively converted from an inactive form to the pore-forming melittin upon cleavage by FAP in the tumor microenvironment.

Methods

We conjugated promelittin-containing FAP-cleavable sequences to pegylated phospholipids and anchored them to reduced graphene oxide (rGO) nanosheets. The resulting nanosheets, PL-rGO, were tested for hemolysis and used for doxorubicin delivery. In vitro cocultures and in vivo tumor growth (n = 5 mice per group) with tissue immunostaining were used to test the selective activation of anticancer chemotherapy by FAP expressed on CAFs.

Results

FAP-specific hemolytic activity of PL-rGO was observed in cocultures of CAFs and HT29 cells but not in HT29 cells alone. Doxorubicin-loaded PL-rGO (Dox/PL-rGO) showed 3.4-fold greater cell-killing efficacy (compared with free Dox in the CAF/HT29 coculture system, effects that were not observed in HT29 cells alone). Intravenously administered Dox/PL-rGO reduced the growth of HT29 tumors more effectively than other treatments (Dox/PL-rGO: mean = 200.6 mm(3), 95% confidence interval [CI] = 148.7 to 252.5 mm(3); free Dox: mean = 697.0 mm(3), 95% CI = 646.9 to 747.1 mm(3), PL: mean = 565.0 mm(3), 95% CI = 550.5 to 579.6 mm(3); Dox/rGO: mean = 637.6 mm(3), 95% CI = 619.5 to 655.7 mm(3); PL-rGO: mean = 464.4 mm(3), 95% CI = 433.0 to 495.8 mm(3)). Immunostaining of tumor tissues revealed that survival of CAFs and HT29 cells was lowest in the group treated with Dox/PL-rGO.

Conclusions

The demonstration of selective activation of PL-rGO by FAP on CAFs suggests that PL-rGO may serve as a tumor microenvironment-responsive anticancer chemotherapy system.

Polyethylene sebacate doxorubicin nanoparticles: role of carbohydrate anchoring on in vitro and in vivo anticancer efficacy

We report carbohydrate-anchored polyethylene sebacate (PES)-Gantrez® AN 119 Doxorubicin hydrochloride (Dox) nanoparticles (NPs) for enhanced anticancer efficacy. The carbohydrates Arabinogalactan (AGn), an adjuvant in anticancer chemotherapy and pullulan (Pul) reported to promote collagen synthesis, were selected as ligands. PES Dox NPs of an average size around 200 nm, greater than 20% w/w Dox loading and negative zeta potential were anchored with Pul, AGn, and Pul-AGn combination by simple incubation. Increase in particle size and zeta potential confirmed carbohydrate anchoring. FTIR confirmed ionic complexation of Dox and Gantrez® AN 119. DSC and XRD demonstrated amorphization of Dox. Higher Dox release in pH 5.5 as compared with pH 7.4 is beneficial for reduced systemic toxicity and enhanced drug release in tumors. Good in vitro serum stability and low hemolysis revealed suitability for intravenous administration. All NPs revealed circulation longevity in normal rats. Pul NPs revealed superior anticancer efficacy in vitro and an 11-fold enhancement in uptake in MCF-7 breast cancer cells. The greater efficacy in vivo is attributed to possible pullulan-mediated integrin receptor uptake and interaction with tumor collagen. Histopathology confirmed safety and suggested promise of Pul NPs in improved anticancer efficacy.

Removal of Chromium(VI) from Aqueous Solutions Using Fe₃O₄ Magnetic Polymer Microspheres Functionalized with Amino Groups

Magnetic polymer microspheres (MPMs) using glycidylmethacrylate (GMA) as a functional monomer were synthesized in the presence of Fe₃O₄ nanoparticles via dispersion polymerization. After polymerization, the magnetic polymer microbeads were modified with ethylenediamine (EDA). The obtained ethylenediamine-functionalized magnetic microspheres (EDA-MPMs) were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM) and Fourier transform infrared (FT-IR) spectroscopy. Then the EDA-MPMs were applied as adsorbents for the removal of Cr(VI) from aqueous solution. Langmuir equation was appropriate to describe the experimental data. The maximum adsorption capacities obtained from the Langmuir model were 236.9, 242.1 and 253.2 mg/g at 298, 308 and 318 K, respectively. The Cr(VI) adsorption equilibrium was established within 120 min and the adsorption kinetics was compatibly described by the pseudo-second order equation. The thermodynamic parameters (ΔG°, ΔH°, ΔS°) of the sorption process revealed that the adsorption was spontaneous and was an endothermic process. The regeneration study demonstrated that the EDA-MPMs could be repeatedly utilized with no significant loss of adsorption efficiency.

Self-assembly of biogenic gold nanoparticles and their use to enhance drug delivery into cells

Integration of the principles of green chemistry into nanotechnology is one of the key issues in nanobio-science research. There is a growing need for development of a synthesis method for producing environmentally harmless nanoparticles in order to avoid adverse effects in medical applications. Here, we report the use of a simple and rapid in vivo biosynthesis method for the preparation of gold nanoparticles (AuNPs) using heavy metal binding proteins (HMBPs) in recombinant Escherichia coli. The HMBPs were found to act as reducing, stabilizing, and capping agents to form the spherical nanoparticles with 5-20 nm in diameter. The size and the shape of AuNPs were modulated by varying the concentration ratio of recombinant proteins in the medium. Only 20 min was required to form AuNPs at room temperature, suggesting that the reaction rate of the proposed method is faster than that of the chemical methods commonly used for nanoparticle synthesis. The AuNPs could be applied as drug carriers in therapeutic applications to improve drug delivery, since they exhibit higher biocompatibility and less toxic effects than chemically synthesized materials. To achieve high cytotoxicity for cancer chemotherapy, doxorubicin (Dox) was released from AuNPs, which can be a more efficient anti-cancer agent than free Dox.

Using hollow carbon nanospheres as a light-induced free radical generator to overcome chemotherapy resistance

Under evolutionary pressure from chemotherapy, cancer cells develop resistance characteristics such as a low redox state, which eventually leads to treatment failures. An attractive option for combatting resistance is producing a high concentration of produced free radicals in situ. Here, we report the production and use of dispersible hollow carbon nanospheres (HCSs) as a novel platform for delivering the drug doxorubicine (DOX) and generating additional cellular reactive oxygen species using near-infrared laser irradiation. These irradiated HCSs catalyzed sufficiently persistent free radicals to produce a large number of heat shock factor-1 protein homotrimers, thereby suppressing the activation and function of resistance-related genes. Laser irradiation also promoted the release of DOX from lysosomal DOX@HCSs into the cytoplasm so that it could enter cell nuclei. As a result, DOX@HCSs reduced the resistance of human breast cancer cells (MCF-7/ADR) to DOX through the synergy among photothermal effects, increased generation of free radicals, and chemotherapy with the aid of laser irradiation. HCSs can provide a unique and versatile platform for combatting chemotherapy-resistant cancer cells. These findings provide new clinical strategies and insights for the treatment of resistant cancers.

Cytotoxicity of graphene oxide and graphene oxide loaded with doxorubicin on human multiple myeloma cells

The purpose of this study was to evaluate the cytotoxicity of human multiple myeloma cells (RPMI-8226) treated with graphene oxide (GO), doxorubicin (DOX), and GO loaded with DOX (GO/DOX). Cell viability was determined using the Cell Counting Kit-8 assay and analyzing the cell cycle and cell apoptosis. Cells treated with GO, GO/DOX, and pure DOX for 24 hours showed a decrease in proliferation. GO/DOX significantly inhibited cell proliferation as compared with pure DOX (P<0.01). When the effects of GO were removed, there was no observed difference between GO/DOX and pure DOX (P>0.05). Flow cytometry analysis of untreated and GO-, DOX-, and GO/DOX-treated cells found no significant differences in the G0/G1 phase (P>0.05), while significant differences were observed in the total apoptotic rates (P<0.05). No significant differences existed in the total apoptotic rates of GO-treated and untreated cells (P>0.05). These findings suggest that GO caused low cytotoxicity and did not induce cell apoptosis or change the cell cycle in multiple myeloma cells. Moreover, GO did not affect the antitumor activity of DOX. In conclusion, GO would be suitable as an anticancer drug nanocarrier and used to treat hematological malignancies.

Green Adsorbents for Wastewaters: A Critical Review

One of the most serious environmental problems is the existence of hazardous and toxic pollutants in industrial wastewaters. The major hindrance is the simultaneous existence of many/different types of pollutants as (i) dyes; (ii) heavy metals; (iii) phenols; (iv) pesticides and (v) pharmaceuticals. Adsorption is considered to be one of the most promising techniques for wastewater treatment over the last decades. The economic crisis of the 2000s led researchers to turn their interest in adsorbent materials with lower cost. In this review article, a new term will be introduced, which is called "green adsorption". Under this term, it is meant the low-cost materials originated from: (i) agricultural sources and by-products (fruits, vegetables, foods); (ii) agricultural residues and wastes; (iii) low-cost sources from which most complex adsorbents will be produced (i.e., activated carbons after pyrolysis of agricultural sources). These "green adsorbents" are expected to be inferior (regarding their adsorption capacity) to the super-adsorbents of previous literature (complex materials as modified chitosans, activated carbons, structurally-complex inorganic composite materials etc.), but their cost-potential makes them competitive. This review is a critical approach to green adsorption, discussing many different (maybe in some occasions doubtful) topics such as: (i) adsorption capacity; (ii) kinetic modeling (given the ultimate target to scale up the batch experimental data to fixed-bed column calculations for designing/optimizing commercial processes) and (iii) critical techno-economical data of green adsorption processes in order to scale-up experiments (from lab to industry) with economic analysis and perspectives of the use of green adsorbents.