Water-dispersible fullerene aggregates as a targeted anticancer prodrug with both chemo- and photodynamic therapeutic actions

Fullerene C60 Conjugate with Folic Acid and Polyvinylpyrrolidone for Targeted Delivery to Tumor Cells

The use of targeted drug delivery systems, including those based on selective absorption by certain receptors on the surface of the target cell, can lead to a decrease in the minimum effective dose and the accompanying toxicity of the drug, as well as an increase in therapeutic efficacy. A fullerene C60 conjugate (FA-PVP-C60) with polyvinylpyrrolidone (PVP) as a biocompatible spacer and folic acid (FA) as a targeting ligand for tumor cells with increased expression of folate receptors (FR) was obtained. Using 13C NMR spectroscopy, FT-IR, UV-Vis spectrometry, fluorometry and thermal analysis, the formation of the conjugate was confirmed and the nature of the binding of its components was established. The average particle sizes of the conjugate in aqueous solutions and cell culture medium were determined using dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The FA-PVP-C60 showed antiradical activity against •DPPH, •OH and O2•-, but at the same time, it was shown to generate 1O2. It was found that the conjugate in the studied concentration range (up to 200 μg/mL) is non-toxic in vitro and does not affect the cell cycle. To confirm the ability of the conjugate to selectively accumulate through folate-mediated endocytosis, its uptake into cells was analyzed by flow cytometry and confocal microscopy. It was shown that the conjugate is less absorbed by A549 cells with low FR expression than by HeLa, which has a high level of expression of this receptor.

Research progress of fullerenes and their derivatives in the field of PDT

In contemporary studies, the predominant utilization of C60 derivatives pertains to their role as photosensitizers or agents that scavenge free radicals. The intriguing coexistence of these divergent functionalities has prompted extensive investigation into water-soluble fullerenes. The photodynamic properties of these compounds find practical applications in DNA cleavage, antitumor interventions, and antibacterial endeavors. Consequently, photodynamic therapy is progressively emerging as a pivotal therapeutic modality within the biomedical domain, owing to its notable levels of safety and efficacy. The essential components of photodynamic therapy encompass light of the suitable wavelength, oxygen, and a photosensitizer, wherein the reactive oxygen species generated by the photosensitizer play a pivotal role in the therapeutic mechanism. The remarkable ability of fullerenes to generate singlet oxygen has garnered significant attention from scholars worldwide. Nevertheless, the limited permeability of fullerenes across cell membranes owing to their low water solubility necessitates their modification to enhance their efficacy and utilization. This paper reviews the applications of fullerene derivatives as photosensitizers in antitumor and antibacterial fields for the recent years.

Water-soluble single molecular probe for simultaneous detection of viscosity and hydrazine

Hydrazine (N₂H₄) can cause serious damage to human health, while intracellular viscosity is highly associated with many diseases and cellular dysfunctions. Herein, we report the synthesis of a dual-responsive organic molecule-based fluorescent probe with excellent water solubility being capable of detection of N₂H₄ and viscosity through dual-fluorescence channels in "turn on" manner for both. Besides sensitive detection of N₂H₄ in aqueous solution with detection limit of 0.135 μM, this probe could be used for vapor N₂H₄ detection in colorimetric and fluorescent manners. In addition, the probe demonstrated viscosity-dependent fluorescence enhancement behavior, and as high as 150-fold enhancement could be obtained at 95% glycerol aqueous solution. Cell imaging experiment revealed that the probe could be used for the discriminating of living and dead cells.

Carbon-based nanostructures for cancer therapy and drug delivery applications

Synthesis, design, characterization, and application of carbon-based nanostructures (CBNSs) as drug carriers have attracted a great deal of interest over the past half of the century because of their promising chemical, thermal, physical, optical, mechanical, and electrical properties and their structural diversity. CBNSs are well-known in drug delivery applications due to their unique features such as easy cellular uptake, high drug loading ability, and thermal ablation. CBNSs, including carbon nanotubes, fullerenes, nanodiamond, graphene, and carbon quantum dots have been quite broadly examined for drug delivery systems. This review not only summarizes the most recent studies on developing carbon-based nanostructures for drug delivery (e.g. delivery carrier, cancer therapy and bioimaging), but also tries to deal with the challenges and opportunities resulting from the expansion in use of these materials in the realm of drug delivery. This class of nanomaterials requires advanced techniques for synthesis and surface modifications, yet a lot of critical questions such as their toxicity, biodistribution, pharmacokinetics, and fate of CBNSs in biological systems must be answered.

Synthesis, Characterization, and Physicochemical Studies Of Orientation-Controlled Multi-Arm PEG Zn(II)/Mg(II) (Aza)Phthalocyanines

Tuning the amphiphilicity of (aza)phthalocyanine hydrophobic cores by introducing multiple polyethylene glycol (PEG) moieties with controlled orientations of their (non)peripheral positions is an innovative approach to fabricating water-soluble macrocyclic materials. Although many water-soluble PEGylated macrocycles have been produced in this way, the ability to generate substances with PEG tails oriented outward from the macrocyclic plane in order to obtain non-aggregated, water soluble forms remains a challenge. In this study, we resolved this issue by developing a methods for the synthesis of four new dual directional PEG containing Zn(II)/Mg(II) amphiphiles (ZnPc-PEG, MgPc-PEG, ZnAzaPc-PEG and MgAzaPc-PEG). In addition, the non-aggregating behaviour, and photophysical and photochemical properties of these PEG-complexes were elucidated.

Targeted chitosan nanoparticles embedded into graphene oxide functionalized with caffeic acid as a potential drug delivery system: New insight into cancer therapy

As a novel drug delivery technology, chitosan (CHI) nanoparticles are encapsulated in graphene oxide (GO) with caffeic acid (CA). The nanocarrier technique combines targeted drug delivery with molecular imaging to provide new cancer insights. Attachment of CA, an anticancer agent for controlled drug release, to functionalized graphene oxide (GON) utilizing 3-aminopropyltriethoxysilane (APTES) was followed by encapsulation of GO with folic acid (FA) attached CHI to produce this novel system. FT-IR was used to characterize and confirm the chemical production process. Brunau-Emmet-Teller (BET) analysis was used to validate multi-holes and nanometric dimensions (1-100 nm) and assess their drug administration use. Release and loading tests showed a pH dependence and implied CA hydrogen-bonding in GON. CA encapsulation and loading percentages are 86 % and 67 %, respectively. The acidic environment (pH 5.3) of tumor cells may produce a larger release of CA, and the release rate of CA maintains a constant trend, indicating the drug is released for more than a week (because the release rate has not reached zero). The proposed method provides a potential candidate for a novel drug delivery system in cancer therapy. The resulting nanohybrid system is a new way to combine biodegradable materials, that can be used in biomedical applications.

Progress in Antiviral Fullerene Research

Unlike traditional small molecule drugs, fullerene is an all-carbon nanomolecule with a spherical cage structure. Fullerene exhibits high levels of antiviral activity, inhibiting virus replication in vitro and in vivo. In this review, we systematically summarize the latest research regarding the different types of fullerenes investigated in antiviral studies. We discuss the unique structural advantage of fullerenes, present diverse modification strategies based on the addition of various functional groups, assess the effect of structural differences on antiviral activity, and describe the possible antiviral mechanism. Finally, we discuss the prospective development of fullerenes as antiviral drugs.

Strategies to Improve Photodynamic Therapy Efficacy of Metal-Free Semiconducting Conjugated Polymers

Photodynamic therapy (PDT) is a noninvasive therapy for cancer and bacterial infection. Metal-free semiconducting conjugated polymers (SCPS) with good stability and optical and electrical properties are promising photosensitizers (PSs) for PDT compared with traditional small-molecule PSs. This review analyzes the latest progress of strategies to improve PDT effect of linear, planar, and three-dimensional SCPS, including improving solubility, adjusting conjugated structure, enhancing PS-doped SCPs, and combining therapies. Moreover, the current issues, such as hypoxia, low penetration, targeting and biosafety of SCPS, and corresponding strategies, are discussed. Furthermore, the challenges and potential opportunities on further improvement of PDT for SCPs are presented.

DFT study on the adsorption of 5-fluorouracil on B40, B39M, and M@B40 (M = Mg, Al, Si, Mn, Cu, Zn)

Based on density functional theory, the adsorption behavior of 5-fluorouracil (5-Fu) on B₄₀ and its derivatives has been explored. It was observed that 5-Fu prefers to combine with the corner boron atom of the B₄₀ cage via one of its oxygen atoms, forming a strong polar covalent B–O bond. The adsorption energy of 5-Fu on B₄₀ was calculated to be −11.15 kcal mol⁻¹, and thus, it can be duly released from B₄₀ by protonation in the slightly acidic environment of tumor tissue, which makes for reducing the toxic and side effects of this drug. Additionally, the substituent and embedding effect of Mg, Al, Si, Mn, Cu, and Zn atoms on the drug delivery performance of B₄₀ have been also considered. We hope this work could offer some implications for the potential application of boron-based nanomaterials, such as B₄₀ in drug delivery.

The adsorption of 5-fluorouracil on B₄₀ and its derivatives has been theoretically studied to provide some implications for the potential application of B₄₀ in drug delivery.

Synthesis of Fullerenes from a Nonaromatic Chloroform through a Newly Developed Ultrahigh-Temperature Flash Vacuum Pyrolysis Apparatus

The flash vacuum pyrolysis (FVP) technique is useful for preparing curved polycyclic aromatic compounds (PAHs) and caged nanocarbon molecules, such as the well-known corannulene and fullerene C₆₀. However, the operating temperature of the traditional FVP apparatus is limited to ~1250 °C, which is not sufficient to overcome the high energy barriers of some reactions. Herein, we report an ultrahigh-temperature FVP (UT-FVP) apparatus with a controllable operating temperature of up to 2500 °C to synthesize fullerene C₆₀ from a nonaromatic single carbon reactant, i.e., chloroform, at 1350 °C or above. Fullerene C₆₀ cannot be obtained from CHCl₃ using the traditional FVP apparatus because of the limitation of the reaction temperature. The significant improvements in the UT-FVP apparatus, compared to the traditional FVP apparatus, were the replacement of the quartz tube with a graphite tube and the direct heating of the graphite tube by impedance heating instead of indirect heating of the quartz tube using an electric furnace. Because of the higher temperature range, UT-FVP can not only synthesize fullerene C₆₀ from single carbon nonaromatic reactants but sublimate some high-molecular-weight compounds to synthesize larger curved PAHs in the future.

Hand-ground fullerene-nanodiamond composite for photosensitized water treatment and photodynamic cancer therapy

The unique capability of fullerene (C₆₀) to absorb light and generate reactive oxygen species (ROS) has been extensively studied for photosensitized water treatment and cancer therapy. Various material synthesis strategies have been proposed in parallel to overcome its intrinsic hydrophobicity and to enhance availability in water and physiological media. We present here a strikingly simple approach to make C₆₀ available to these applications by hand-grinding dry C₆₀ powder with nanodiamond (ND) using a mortar and pestle. The resulting ND-C₆₀ composite was found to form a stable aqueous colloidal suspension and efficiently drive photosensitized production of ROS under visible light illumination. ND-C₆₀ rapidly adsorbed and oxidized organic contaminants by photogenerated ROS. In the experiments for photodynamic cancer therapy, ND-C₆₀ was internalized by cancer cells and induced cell apoptosis without noticeable toxicity. Treatment of tumor-bearing mice with ND-C₆₀ and light irradiation resulted in tumor shrinkage and prolonged survival time.

Ligand-Targeted Delivery of Photosensitizers for Cancer Treatment

Photodynamic therapy (PDT) is a promising cancer treatment which involves a photosensitizer (PS), light at a specific wavelength for PS activation and oxygen, which combine to elicit cell death. While the illumination required to activate a PS imparts a certain amount of selectivity to PDT treatments, poor tumor accumulation and cell internalization are still inherent properties of most intravenously administered PSs. As a result, common consequences of PDT include skin photosensitivity. To overcome the mentioned issues, PSs may be tailored to specifically target overexpressed biomarkers of tumors. This active targeting can be achieved by direct conjugation of the PS to a ligand with enhanced affinity for a target overexpressed on cancer cells and/or other cells of the tumor microenvironment. Alternatively, PSs may be incorporated into ligand-targeted nanocarriers, which may also encompass multi-functionalities, including diagnosis and therapy. In this review, we highlight the major advances in active targeting of PSs, either by means of ligand-derived bioconjugates or by exploiting ligand-targeting nanocarriers.

Evaluation of the Biodistribution of Serinolamide-Derivatized C60 Fullerene

Carbon nanoparticles have consistently been of great interest in medicine. However, there are currently no clinical materials based on carbon nanoparticles, due to inconsistent biodistribution and excretion data. In this work, we have synthesized a novel C60 derivative with a metal chelating agent (1,4,7-Triazacyclononane-1,4,7-triacetic acid; NOTA) covalently bound to the C60 cage and radiolabeled with copper-64 (t1/2 = 12.7 h). Biodistribution of the material was assessed in vivo using positron emission tomography (PET). Bingel-Hirsch chemistry was employed to functionalize the fullerene cage with highly water-soluble serinolamide groups allowing this new C60 conjugate to clear quickly from mice almost exclusively through the kidneys. Comparing the present results to the larger context of reports of biocompatible fullerene derivatives, this work offers an important evaluation of the in vivo biodistribution, using experimental evidence to establish functionalization guidelines for future C60-based biomedical platforms.

Multifunctional phototheranostic nanomedicine for cancer imaging and treatment

Cancer, as one of the most life-threatening diseases, shows a high fatality rate around the world. When improving the therapeutic efficacy of conventional cancer treatments, researchers also conduct extensive studies into alternative therapeutic approaches, which are safe, valid, and economical. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), are tumor-ablative and function-reserving oncologic interventions, showing strong potential in clinical cancer treatment. During phototherapies, the non-toxic phototherapeutic agents can be activated upon light irradiation to induce cell death without causing much damage to normal tissues. Besides, with the rapid development of nanotechnology in the past decades, phototheranostic nanomedicine also has attracted tremendous interests aiming to continuously refine their performance. Herein, we reviewed the recent progress of phototheranostic nanomedicine for improved cancer therapy. After a brief introduction of the therapeutic principles and related phototherapeutic agents for PDT and PTT, the existing works on developing of phototheranostic nanomedicine by mainly focusing on their categories and applications, particularly on phototherapy-synergized cancer immunotherapy, are comprehensively reviewed. More importantly, a brief conclusion and future challenges of phototheranostic nanomedicine from our point of view are delivered in the last part of this article.

Novel Glycosylated Naphthalimide-Based Activatable Fluorescent Probe: A Tool for the Assessment of Hexosaminidase Activity and Intracellular Hexosaminidase Imaging

The development of effective detection methods for hexosaminidase is of great importance for the rapid screening of potential inhibitors in vitro and for the early diagnosis of related diseases ex vivo. In this study, the activatable fluorescent probes that are based on naphthalimide decorated with ethylene glycol units were synthesized using N-acetyl-β-d-glucosaminide as a hexosaminidase-responsive group. When exposed to this enzyme, the glucoside-linked naphthalimide moiety of 1c can be cleaved quickly with significant changes in both color (from colorless to yellow) and fluorescence (from blue to green). Probe 1c shows better water-solubility and fluorescence properties than common substrate 4-methylumbelliferyl N-acetyl-β-d-glucosaminide. Furthermore, the response mechanism of 1c to hexosaminidase was evaluated using HPLC analysis and TD-DFT calculations. Molecular docking was performed to investigate the interaction mode. In addition, 1c has successfully achieved the straightforward rapid discovery of effective hexosaminidase inhibitors. Fluorescence imaging experiments indicate that 1c has good cell safety and can be employed as a useful tool for detecting intracellular hexosaminidase activity.

Protein Shell-Encapsulated Pt Clusters as Continuous O2-Supplied Biocoats for Photodynamic Therapy in Hypoxic Cancer Cells

As a highly oxygen-dependent process, the effect of photodynamic therapy is often obstructed by the premature leakage of photosensitizers and the lack of oxygen in hypoxic cancer cells. To overcome these limitations, this study designs bovine serum albumin protein (BSA)-encapsulated Pt nanoclusters (PtBSA) as O₂-supplied biocoats and further incorporates them with mesoporous silica nanospheres to develop intelligent nanoaggregates for achieving improved therapeutic outcomes against hypoxic tumors. The large number of amino groups on BSA can provide sufficient functional groups to anchor tumor targeting agents and thus enhance the selective cellular uptake efficiency. Owing to the outstanding biocompatibility features of BSA and the state-of-the-art catalytic activity of Pt nanoclusters, the nanocomposites have lower dark cytotoxicity, and O₂ continuously evolves via the decomposition of H₂O₂ in a tumor microenvironment. Both in vivo and in vitro experiments indicate that the resulting nanocomposites can effectively relieve hypoxic conditions, specifically induce necrotic cell apoptosis, and remarkably hinder tumor growth. Our results illuminate the great potential of BSA-encapsulated Pt nanoclusters as versatile biocoats in designing intelligent nanocarriers for hypoxic-resistant photodynamic therapy.

Threatening cancer with nanoparticle aided combination oncotherapy

Employing combination therapy has become obligatory in cancer cases exhibiting high tumor load, chemoresistant tumor population, and advanced disease stages. Realization of this fact has now led many of the combination oncotherapies to become an integral part of anticancer regimens. Combination oncotherapy may encompass a combination of anticancer agents belonging to a similar therapeutic category or that of different therapeutic categories (e.g. chemotherapy + gene therapy). Differences in the physicochemical properties, pharmacokinetics and biodistribution pattern of different payloads are the major constraints that are faced by combination chemotherapy. Concordant efforts in the field of nanotechnology and oncology have emerged with several approaches to solve the major issues encountered by combination therapy. Unique colloidal behaviors of various types of nanoparticles and differential targeting strategies have accorded an unprecedented ability to optimize combination oncotherapeutic delivery. Nanocarrier based delivery of the various types of payloads such as chemotherapeutic agents and other anticancer therapeutics such as small interfering ribonucleic acid (siRNA), chemosensitizers, radiosensitizers, and antiangiogenic agents have been addressed in the present review. Various nano-delivery systems like liposomes, polymeric nanoparticles, polymerosomes, dendrimers, micelles, lipid based nanoparticles, prodrug based nanocarriers, polymer-drug conjugates, polymer-lipid hybrid nanoparticles, carbon nanotubes, nanosponges, supramolecular nanocarriers and inorganic nanoparticles (gold nanoparticles, silver nanoparticles, magnetic nanoparticles and mesoporous silica based nanoparticles) that have been extensively explored for the formulation of multidrug delivery is an imperative part of discussion in the review. The present review features the outweighing benefits of combination therapy over mono-oncotherapy and discusses several existent nanoformulation strategies that facilitate a successful combination oncotherapy. Several obstacles that may impede in transforming nanotechnology-based combination oncotherapy from bench to bedside, and challenges associated therein have also been discussed in the present review.

Combination Effect of Silver Nanoparticles and Histone Deacetylases Inhibitor in Human Alveolar Basal Epithelial Cells

Although many treatment strategies have been reported for lung disease, the mechanism of combination therapy using silver nanoparticles (AgNPs) and histone deacetylases inhibitors (HDACi) remains unclear. Therefore, innovative treatment strategies are essential for addressing the therapeutic challenges of this highly aggressive lung cancer. AgNPs and HDACi seem to be the best candidates for anticancer therapy because of their anti-proliferative effect in a variety of cancer cells. First, we synthesized AgNPs using wogonin as a reducing and stabilizing agent, following which the synthesized AgNPs were characterized by various analytical techniques. The synthesized AgNPs exhibited dose- and size-dependent toxicity towards A549 cells. Interestingly, the combination of AgNPs and MS-275 significantly induces apoptosis, which was accompanied by an increased level of reactive oxygen species (ROS); leakage of lactate dehydrogenase (LDH); secretion of TNFα; dysfunction of mitochondria; accumulation autophagosomes; caspase 9/3 activation; up and down regulation of pro-apoptotic genes and anti-apoptotic genes, respectively; and eventually, induced DNA-fragmentation. Our findings suggest that AgNPs and MS-275 induce cell death in A549 lung cells via the mitochondrial-mediated intrinsic apoptotic pathway. Finally, our data show that the combination of AgNPs and MS-275 is a promising new approach for the treatment of lung cancer and our findings contribute to understanding the potential roles of AgNPs and MS-275 in pulmonary disease. However, further study is warranted to potentiate the use of this combination therapy in cancer therapy trials.

Fullerene as a doxorubicin nanotransporter for targeted breast cancer therapy: Capillary electrophoresis analysis

The clinical use of doxorubicin (DOX) is limited by dose-related cardiomyopathy, which becomes more prevalent with increasing cumulative doses of the drug. Complexes of fullerene with DOX were designed and studied using biophysical methods. The ability of DOX to release from fullerene at different pHs was analyzed. It has been shown that the size of the fullerene-DOX complexes was ∼280 nm. The zeta potential for fullerene was -30 mV, for DOX -8 mV, and for fullerene-DOX conjugates -24 mV. Drug release was studied by CE with LIF detection. When fullerene-DOX conjugates were separated in a pH 7.5 buffer, 43% of all DOX signals were derived from free DOX, with the signal increasing as pH decreased. At pH 5.25, all DOX had been released and 100% of the signal was derived from free DOX. The release of DOX from complexes with fullerene at lower pH can be used in targeted antineoplastic therapy, resulting in lower toxicity for less acidic non-target tissue.

Nucleosome-inspired nanocarrier obtains encapsulation efficiency enhancement and side effects reduction in chemotherapy by using fullerenol assembled with doxorubicin

Chemodrugs have been widely used to treat cancer; however, the chemotherapy usually leads to serious side effects and failure. Various nanomaterials and strategies have been explored for drug delivery to improve the efficacy of chemodrugs. One key to loading chemodrugs onto a nano-delivery system is enhancement of the encapsulation efficiency, especially for polymeric nanoparticles being loaded with hydrophilic drugs. Inspired by the ability of eukaryote to package millions of genes in the nucleus wrapping and condensing DNA around histones to form chromosomes, here we developed a karyon-like hybrid nanoparticle to achieve ultra-high encapsulation of doxorubicin (Dox) with reduced side effects. We utilized fullerenol as a "histone", packaged a great number of Dox, and used PEG-PLGA as the "karyotheca" coating the "nucleosome" (fullerenol and Dox complex) to stabilize the complex. It is noteworthy that the encapsulation efficiency of Dox in the polymeric micelles was increased from ∼5% to ∼79%. What's more, the biomimetic-inspired delivery system significantly reduced the chemodrug side effects by utilizing the radical scavenging ability of fullerenol. This novel drug-delivery design approach provides useful insights for improving the applicability of fullerenol in drug delivery systems for cancer therapy.

Does C60 fullerene act as a transporter of small aromatic molecules?

C₆₀ fullerene is reported to directly interact with biomolecules, such as aromatic mutagens or anticancer drugs. Therefore, it is extensively studied for its potential application in the fields of drug delivery and chemoprevention. Understanding the nature of fullerene-drugs interactions might contribute to optimization and modification of the existing chemotherapy systems. Possible interactions between ICR-191, a model acridine mutagen, with well-established biophysical properties and mutagenic activity, and C₆₀ fullerene aqueous solution were investigated by broad range of biophysical methods, such as Dynamic Light Scattering, Isothermal Titration Calorimetry, and Atomic Force Microscopy. Additionally, to determine biological activity of ICR-191-C₆₀ fullerene mixtures, Ames mutagenicity test was employed. It was demonstrated that C₆₀ fullerene interacts non-covalently with ICR-191 and has strong affinity to bacterial membranes. The obtained results provide practical insight into C₆₀ fullerene interactions with aromatic compounds.

Therapeutic Nanosystem Consisting of Singlet-Oxygen-Responsive Prodrug and Photosensitizer Excited by Two-Photon Light

Using light as the sole stimulus and employing the generated singlet oxygen as a therapeutic agent and the trigger to activate chemo-drug release could serve as an elegant way to bring into full play the advantageous features of light and enhance therapeutic efficacy through a combination of chemotherapy and photodynamic therapy. Herein a liposomal drug system has been developed by embedding a fluorescent photosensitizer and a prodrug into phospholipid vesicles. Upon one- or two-photon light irradiation, the photosensitizer generates singlet oxygen, which removes the protecting group of the prodrug and subsequently causes the release of the active drug chlorambucil. With the combined action of O21 and chlorambucil, highly controllable cytotoxicity toward cancer cells was achieved. In addition, the fluorescent photosensitizer gives out fluorescent signal acting as the drug monitoring agent. This strategy may provide an efficient approach for cancer treatment and some useful insights for designing light-stimulated on-demand therapeutic systems.

A bioorthogonal nanosystem for imaging and in vivo tumor inhibition

Bioorthogonal bond-cleavage reactions have emerged as promising tools for manipulating biological processes, still the therapeutic effect of these reactions in vivo needs to be explored. Herein a bioorthogonal-activated prodrug has been developed for bioimaging and therapy, which is composed of a Pd-mediated cleavable propargyl, a coumarin fluorophore and a potent anticancer drug. In vitro investigations show that, the presence of a Pd complex induces the cleavage of propargyl and subsequently trigger the cascade of reactions, thereby activating the coumarin fluorophore for imaging and releasing the anticancer drug for therapy. Both the prodrug and Pd complex were then separately encapsulated into phospholipid liposomes to form a two-component bioorthogonal nanosystem. The lyposomal nanosystem can be readily internalized by HeLa cells and displays strong intracellular fluorescence under one- or two-photon excitation, indicating the release of the active drug in cells as a result of the Pd-mediated bioorthogonal bond-cleavage reaction. More importantly, the nanosystem shows considerable high activity and exerts efficient inhibition towards tumor growth in a mouse model. This work demonstrates that, if properly formulated, a bioorthogonal system can perform well in vivo. This strategy may offer a new approach for designing bioorthogonal prodrugs with imaging and therapeutic capability.

A two-photon-activated prodrug for therapy and drug release monitoring

A two-photon-activated prodrug has been developed for drug release monitoring and photo-controllable therapy.

C60@lysozyme: a new photosensitizing agent for photodynamic therapy

C₆₀@lysozyme showed significant visible light-induced singlet oxygen generation in a physiological environment, indicating the potential of this hybrid as an agent for photodynamic therapy.

GSH Induced Controlled Release of Levofloxacin from a Purpose-Built Prodrug: Luminescence Response for Probing the Drug Release in Escherichia coli and Staphylococcus aureus

Fluoroquinolones are third-generation broad spectrum bactericidal antibiotics and work against both Gram-positive and Gram-negative bacteria. Levofloxacin (L), a fluoroquinolone, is widely used in anti-infective chemotherapy and treatment of urinary tract infection and pneumonia. The main pathogen for urinary tract infections is Escherichia coli, and Streptococcus pneumoniae is responsible for pneumonia, predominantly a lower respiratory tract infection. Poor permeability of L leads to the use of higher dose of this drug and excess drug in the outer cellular fluid leads to central nervous system (CNS) abnormality. One way to counter this is to improve the lipophilicity of the drug molecule, and accordingly, we have synthesized two new Levofloxacin derivatives, which participated in the spatiotemporal release of drug via disulfide bond cleavage induced by glutathione (GSH). Recent studies with Streptococcus mutants suggest that it is localized in epithelial lining fluid (ELF) of the normal lower respiratory tract and the effective [GSH] in ELF is ∼430 μM. E. coli typically cause urinary tract infections and the concentration of GSH in porcine bladder epithelium is reported as 0.6 mM for a healthy human. Thus, for the present study we have chosen two important bacteria (Gram + ve and Gram - ve), which are operational in regions having high extracellular GSH concentration. Interestingly, this supports our design of new lipophilic Levofloxacin based prodrugs, which released effective drug on reaction with GSH. Higher lipophilicity favored improved uptake of the prodrugs. Site specific release of the drug (L) could be achieved following a glutathione mediated biochemical transformation process through cleavage of a disulfide bond of these purpose-built prodrugs. Further, appropriate design helped us to demonstrate that it is possible also to control the kinetics of the drug release from respective prodrugs. Associated luminescence enhancement helps in probing the release of the drug from the prodrug in bacteria and helps in elucidating the mechanistic pathway of the transformation. Such an example is scarce in the contemporary literature.

Bioavailability of Fullerene under Environmentally Relevant Conditions: Effects of Humic Acid and Fetal Bovine Serum on Accumulation in Lipid Bilayers and Cellular Uptake

Carbon fullerene (C60) has emerged at the forefront of nanoscale research and application due to its unique properties. As the production of this nanoparticle rapidly increases, it can be released into natural aquatic environments and can accumulate in biological systems. This research examined the effects of humic acid and fetal bovine serum (FBS), which are ubiquitous in aquatic environments and representative of blood plasma in living organisms, respectively, on bioavailability of fullerene. Bioavailability was investigated using in vitro methods for lipid membrane accumulation and cellular uptake studies. Humic acid and FBS significantly changed the characteristics of fullerene including its particle size and surface charge. The effects of humic acid on lipid accumulation of fullerene depended on the lipid head charge. FBS also significantly decreased the lipid accumulation when positively charged and zwitterionic head groups were present on the lipids, possibly due to the higher steric repulsion of the protein coated nanoparticles. In addition, both humic acid and FBS protein effectively lowered the amounts of fullerene taken up by Caco-2 cells, which are derived from a human colorectal adenocarcinoma and have similar functions to the small intestinal epithelium. Results of this study suggest that surface modification of fullerene by environmentally relevant matrices can significantly affect the biological transport, as well as the possible toxicity of this nanomaterial.

Fullerene/photosensitizer nanovesicles as highly efficient and clearable phototheranostics with enhanced tumor accumulation for cancer therapy

A novel phototheranostic platform based on tri-malonate derivative of fullerene C70 (TFC70)/photosensitizer (Chlorin e6, Ce6) nanovesicles (FCNVs) has been developed for effective tumor imaging and treatment. The FCNVs were prepared from amphiphilic TFC70-oligo ethylene glycol -Ce6 molecules. The developed FCNVs possessed the following advantages: (i) high loading efficiency of Ce6 (up to ∼57 wt%); (ii) efficient absorption in near-infrared light region; (iii) enhanced cellular uptake efficiency of Ce6 in vitro and in vivo; (iv) good biocompatibility and total clearance out from the body. These unique properties suggest that the as-prepared FCNVs could be applied as an ideal theranostic agent for simultaneous imaging and photodynamic therapy of tumor. This finding may provide a good solution to highly efficient phototheranostic applications based on fullerene derivatives fabricated nanostructures.

Tailoring the dendrimer core for efficient gene delivery

Dendrimers have been widely used as non-viral gene vectors due to well-defined chemical structures, high density of cationic charges and ease of surface modification. Although a large number of studies have reported the important roles of dendrimer architecture, component, generation and surface functionality in gene delivery, the effect of dendrimer core on this issue still remains unclear. Recent literatures suggest that a slight alternation in dendrimer core has a profound effect in the transfection efficacy and biocompatibility. In this review, we will discuss the transfection mechanism of dendrimers with different types of cores in respect of flexibility, hydrophobicity and functionality. We hope to open a possibility of designing efficient dendrimers for gene delivery by choosing a proper dendrimer core.

STATEMENT OF SIGNIFICANCE

As a branch of researches on dendrimers and dendritic polymers, the design of biocompatible and high efficient polymeric gene carriers has attracted increasing attentions during these years. Although the effect of dendrimer generation, species, architecture and surface functionality on gene delivery have been widely reported, the effect of dendrimer core on this issue still remains unclear. Recent literatures suggest that a minor variation on the dendrimer core has a profound effect in the transfection efficacy and biocompatibility. This critical review summarized the dendrimers with different types of cores and discussed the transfection mechanism with particular focus on the flexibility, hydrophobicity, and functionality. It is hoped to provide a new insight to design efficient and safe dendrimer-based gene vectors by choosing a proper core. To the best of our knowledge, this is the first review on the effect of dendrimer core on gene delivery. The findings obtained in this filed are of central importance in the design of efficient polymeric gene vectors. This article will appeal a wide readership such as physical chemist, dendrimer chemist, biological chemist, pharmaceutical scientist, and biomaterial researchers. We hope that this review article can be published by Acta Biomaterialia, a top journal that publishes important reviews in the field of biomaterials science.

Biological applications of hydrophilic C60 derivatives (hC60s)- a structural perspective

Reactive oxygen species (ROS) generation and radical scavenging are dual properties of hydrophilic C60 derivatives (hC60s). hC60s eliminate radicals in dark, while they produce reactive oxygen species (ROS) in the presence of irradiation and oxygen. Compared to the pristine C60 suspension, the aqueous solution of hC60s is easier to handle in vivo. hC60s are diverse and could be placed into two general categories: covalently modified C60 derivatives and pristine C60 solubilized non-covalently by macromolecules. In order to present in detail, the above categories are broken down into 8 parts: C60(OH)n, C60 with carboxylic acid, C60 with quaternary ammonium salts, C60 with peptide, C60 containing sugar, C60 modified covalently or non-covalently solubilized by cyclodextrins (CDs), pristine C60 delivered by liposomes, functionalized C60-polymer and pristine C60 solubilized by polymer. Each hC60 shows the propensity to be ROS producer or radical scavenger. This preference is dependent on hC60s structures. For example, major application of C60(OH)n is radical scavenger, while pristine C60/γ-CD complex usually serves as ROS producer. In addition, the electron acceptability and innate hydrophobic surface confer hC60s with O2 uptake inhibition, HIV inhibition and membrane permeability. In this review, we summarize the preparation methods and biological applications of hC60s according to the structures.

C60 fullerene as synergistic agent in tumor-inhibitory Doxorubicin treatment

Background

Doxorubicin (Dox) is one of the most potent anticancer drugs, but its successful use is hampered by high toxicity caused mainly by generation of reactive oxygen species. One approach to protect against Dox-dependent chemical insult is combined use of the cytostatic drug with antioxidants. C₆₀ fullerene has a nanostructure with both antioxidant and antitumor potential and may be useful in modulating cell responses to Dox.

Objective

The aim of this study was to estimate the antitumor effect and antioxidant enzyme activity of combined C₆₀ fullerene and Dox (C₆₀ + Dox) in the liver and heart of mice with Lewis lung carcinoma compared with Dox treatment alone.

Methods

Highly stable pristine C₆₀ fullerene aqueous colloid solution (concentration 1.0 mg/ml, average hydrodynamic diameter of nanoparticles 50 nm) was used in the study and characterized by means of atomic force microscopy (AFM). The in vivo investigation of C₆₀-Dox action was performed via the standard methods of histological and enzyme activity analyses.

Results

Dox (total dose 2.5 mg/kg) combined with C₆₀ fullerene (total dose 25 mg/kg) in tumor-bearing animals resulted in tumor growth inhibition, prolongation of life, metastasis inhibition, and increased number of apoptotic tumor cells and was more effective than the corresponding course of Dox treatment alone. C₆₀ fullerene demonstrated a protective effect against superoxide dismutase and glutathione peroxidase inhibition induced by Dox-dependent oxidative insult in the liver and heart.

Conclusion

Combined treatment with C₆₀ + Dox is considered to be a promising approach for cancer chemotherapy.

Hyaluronic Acid-Modified Multifunctional Q-Graphene for Targeted Killing of Drug-Resistant Lung Cancer Cells

Considering the urgent need to explore multifunctional drug delivery system for overcoming multidrug resistance, we prepared a new nanocarbon material Q-Graphene as a nanocarrier for killing drug-resistant lung cancer cells. Attributing to the introduction of hyaluronic acid and rhodamine B isothiocyanate (RBITC), the Q-Graphene-based drug delivery system was endowed with dual function of targeted drug delivery and fluorescence imaging. Additionally, doxorubicin (DOX) as a model drug was loaded on the surface of Q-Graphene via π-π stacking. Interestingly, the fluorescence of DOX was quenched by Q-Graphene due to its strong electron-accepting capability, and a significant recovery of fluorescence was observed, while DOX was released from Q-Graphene. Because of the RBITC labeling and the effect of fluorescence quenching/restoring of Q-Graphene, the uptake of nanoparticles and intracellular DOX release can be tracked. Overall, a highly promising multifunctional nanoplatform was developed for tracking and monitoring targeted drug delivery for efficiently killing drug-resistant cancer cells.

Smart pH-responsive and high doxorubicin loading nanodiamond for in vivo selective targeting, imaging, and enhancement of anticancer therapy

We introduce a simple and effective strategy to design a promising drug delivery platform for improving the biomedical applications of smart nanodiamond carriers.