Nanodiamond-based multifunctional platform for oral chemo-photothermal combinational therapy of orthotopic colon cancer.

Combination therapy system has become a promising strategy for achieving favorable antitumor efficacy. Herein, a novel oral drug delivery system with colon localization and tumor targeting functions was designed for orthotopic colon cancer chemotherapy and photothermal combinational therapy. The polydopamine coated nanodiamond (PND) was used as the photothermal carrier, through the coupling of sulfhydryl-polyethylene glycol-folate (SH-PEG-FA) on the surface of PND to achieve systematic colon tumor targeting, curcumin (CUR) was loaded as the model drug, and then coated with chitosan (CS) to achieve the long gastrointestinal tract retention and colon localization functions to obtain PND-PEG-FA/CUR@CS nanoparticles. It has high photothermal conversion efficiency and good photothermal stability and exhibited near-infrared (NIR) laser-responsive drug release behavior. Folate (FA) modification effectively promotes the intracellular uptake of nanoparticles by CT26 cells, and the combination of chemotherapy and photothermal therapy (CT/PTT) can enhance cytotoxicity. Compared with free CUR group, nanoparticles prolonged the gastrointestinal tract retention time, accumulated more in colon tumor tissues, and exhibited good photothermal effect in vivo. More importantly, the CT/PTT group exhibited satisfactory tumor growth inhibition effects with good biocompatibility in vivo. In summary, this oral drug delivery system is an efficient platform for chemotherapy and photothermal combinational therapy of orthotopic colon cancer.

Disruption of insect immunity using analogs of the pleiotropic insect peptide hormone Neb-colloostatin: a nanotech approach for pest control II.

This work continues our studies on the pleiotropic activity of the insect peptide Neb-colloostatin in insects. In vivo immunological bioassays demonstrated that hemocytotoxic analogs of Neb-colloostatin injected into Tenebrio molitor significantly reduced the number of hemocytes in the hemolymph and impaired phagocytosis, nodulation and phenoloxidase activities in the insects. Among the analogs tested, [Ala1]-,[Val1]-, [Hyp4]- and [Ach4]-colloostatin were particularly potent in disrupting cellular immunity in larvae, pupae and adult insects. This result suggests that the most effective analogs showed increases in the bioactivity period in the hemolymph of insects when compared to Neb-colloostatin. Recently, we demonstrated that it is possible to introduce Neb-colloostatin through the cuticle of an insect into the hemolymph when the peptide is coupled with nanodiamonds. In this study, we showed that [Ala1]-, [Val1]-, [Hyp4]- and [Ach4]-colloostatin, when complexed with nanodiamonds, may also pass through the cuticle into the hemolymph and induce long-term impairments of immunity in T. molitor at all developmental stages. Studies on the tissue selectivity and effectiveness of Neb-colloostatin analogs and efficient methods for their introduction into insects may contribute to the development of eco-friendly pest control methods based on bioactive peptidomimetics.

Nanodiamonds for bioapplications, recent developments.

The world of biomedical research is in constant evolution, requiring more and more conditions and norms through pre-clinic and clinic studies. Nanodiamonds (NDs) with exceptional optical, thermal and mechanical properties emerged on the global scientific scene and recently gained more attention in biomedicine and bioanalysis fields. Many problematics have been deliberated to better understand their in vitro and in vivo efficiency and compatibility. Light was shed on their synthesis, modification and purification steps, as well as particle size and surface properties in order to find the most suitable operating conditions. In this review, we present the latest advances of NDs use in bioapplications. A large variety of subjects including anticancer and antimicrobial systems, wound healing and tissue engineering management tools, but also bioimaging and labeling probes are tackled. The key information resulting from these recent works were evidenced to make an overview of the potential features of NDs, with a special look on emerging therapeutic and diagnosis combinations.

Water-Soluble Nanoconjugate for Enhanced Cellular Delivery of Receptor-Targeted Magnetic Resonance Contrast Agents.

ProGlo is an efficient steroid receptor-targeted magnetic resonance (MR) imaging contrast agent (CA). It has been shown to bind to the progesterone receptor (PR) and produce enhanced image contrast in PR-positive cells and tissues in vitro and in vivo. However, the hydrophobicity of the steroid targeting domain of ProGlo (logP = 1.4) limits its formulation and delivery at clinically relevant doses. In this work, a hydrophobic moiety was utilized to drive efficient adsorption onto nanodiamond (ND) clusters to form a water-soluble nanoconstruct (logP = -2.4) with 80% release in 8 h under biological conditions. In cell culture, the ND-ProGlo construct delivered increased concentrations of ProGlo to target cells compared to ProGlo alone. Importantly, these results were accomplished without the use of solvents such as DMSO, providing a significant advance toward formulating ProGlo for translational applications. Biodistribution studies confirm the delivery of ProGlo to PR(+) tissues with enhanced efficacy over untargeted controls. These results demonstrate the potential for a noncovalent ND-CA construct as a general strategy for solubilizing and delivering hydrophobic targeted MR CAs.

Nanodiamonds: Minuscule gems that ferry antineoplastic drugs to resistant tumors.

Remarkable efforts are currently devoted to the area of nanodiamonds (NDs) research due to their superior properties viz: biocompatibility, minute size, inert core, and tunable surface chemistry. The use of NDs for the delivery of anticancer drugs has been at the forefront of NDs applications owing to their ability to increase chemosensitivity, sustain drug release, and minimize drug side effects. Accelerated steps towards the move of NDs from bench side to bedside have been recently witnessed. In this review, the effects of NDs production and purification techniques on NDs' final properties are discussed. Special concern is given to studies focusing on NDs use for anticancer drug delivery, stability enhancement and mediated targeted delivery. The aim of this review is to put the results of studies oriented towards NDs-mediated anticancer drug delivery side by side such that the reader can assess the potential use of NDs in clinics and follow up the upcoming results of clinical testing of NDs on animals and humans.

Studying the chemical reactivity properties of the target tumor-environment tripeptides NGR (asparagine-glycine-arginine) and RGD (arginine-glycine-aspartic acid) in their interactions with tamoxifen through conceptual density functional theory.

Here, we report theoretical research into the interaction of the drug tamoxifen drug with tripeptides found in the tumor environment-specifically, asparagine-glycine-arginine (NGR) and arginine-glycine-aspartic acid (RGD). Reactivity parameters of these tripeptides were calculated and their intrinsic reactivities and cross-reactivities were analyzed. The interactions of the tripeptides with the nanodiamond-tamoxifen (ND-TAM) complex where the nanodiamond acts as a nanocarrier were also examined theoretically. In addition, their intestinal absorption was predicted based on the polar surface area. The results showed that tamoxifen interacts with RGD, and this interaction remained after the addition of the nanodiamond. An analysis of the chemical hardnesses of the tripeptides was carried out to explore their possible use as synthetic vectors when joined to the nanodiamond. Results indicated that NGR is the most stable of the tripeptides and could be used for active targeting. All calculations were implemented using the conceptual framework of density functional theory.

Nanodiamond autophagy inhibitor allosterically improves the arsenical-based therapy of solid tumors.

Arsenic trioxide (ATO) is a successful chemotherapeutic drug for blood cancers via selective induction of apoptosis; however its efficacy in solid tumors is limited. Here we repurpose nanodiamonds (NDs) as a safe and potent autophagic inhibitor to allosterically improve the therapeutic efficacy of ATO-based treatment in solid tumors. We find that NDs and ATO are physically separate and functionally target different cellular pathways (autophagy vs. apoptosis); whereas their metabolic coupling in human liver carcinoma cells remarkably enhances programmed cell death. Combination therapy in liver tumor mice model results in ~91% carcinoma decrease as compared with ~28% without NDs. Treated mice show 100% survival rate in 150 days with greatly reduced advanced liver carcinoma-associated symptoms, and ~80% of post-therapy mice survive for over 20 weeks. Our work presents a novel strategy to harness the power of nanoparticles to broaden the scope of ATO-based therapy and more generally to fight solid tumors.

Nanodiamond applications in skin preparations.

The biocompatibility and nontoxicity of nanodiamonds (NDs) in combination with their excellent physical performance have rendered them attractive candidates for biomedical applications. NDs have great potential in drug nanoformulations because of their small size compared with other carbon nanomaterials. They are nontoxic with excellent adsorption properties and can be formulated into skin care products. Even though NDs have shown encouraging potential in skin preparations, only a few studies have reviewed their application in topical drug delivery systems. Therefore, here we focus on the application of NDs in skin care preparations, skin cancer medication, and wound healing. We also highlight the development of topical drug delivery by NDs and their cytotoxicity.

Detonation nanodiamonds are promising nontoxic delivery system for urothelial cells.

Detonation nanodiamonds (DNDs) are carbon-based nanomaterials that are among the most promising nanoparticles available for biomedical applications so far. This is due to their biocompatibility, which could be contributed to their inert core and conformable surface nature. However, DNDs cytotoxicity for urothelial cells and the routes of their internalization remains an open question in the aspect of nanodiamond surface. We therefore analyzed four types of DNDs for cytotoxicity and internalization with normal urothelial cells and two types of cancer urothelial cell lines in vitro. Viability of any of the cell types we used was not compromised with any of four DNDs we evaluated after 24-, 48- and 72-h incubation in three different concentrations of DNDs. Transmission electron microscopy revealed that all four types of DNDs were endocytosed into all three types of urothelial cells tested here. We observed DNDs in endosomes, as well as in multivesicular bodies and multilamellar bodies. These results propose using of DNDs as a delivery system for urological applications in human nanomedicine.

Harnessing the cross-talk between tumor cells and tumor-associated macrophages with a nano-drug for modulation of glioblastoma immune microenvironment.

Glioblastoma (GBM) is the most frequent and malignant brain tumor with a high mortality rate. The presence of a large population of macrophages (Mφ) in the tumor microenvironment is a prominent feature of GBM and these so-called tumor-associated Mφ (TAM) closely interact with the GBM cells to promote the survival, progression and therapy resistance of the GBM. Various therapeutic strategies have been devised either targeting the GBM cells or the TAM but few have addressed the cross-talks between the two cell populations. The present study was carried out to explore the possibility of exploiting the cross-talks between the GBM cells (GC) and TAM for modulation of the GBM microenvironment through using Nano-DOX, a drug composite based on nanodiamonds bearing doxorubicin. In the in vitro work on human cell models, Nano-DOX-loaded TAM were first shown to be viable and able to infiltrate three-dimensional GC spheroids and release cargo drug therein. GC were then demonstrated to encourage Nano-DOX-loaded TAM to unload Nano-DOX back into GC which consequently emitted damage-associated molecular patterns (DAMPs) that are powerful immunostimulatory agents as well as indicators of cell damage. Nano-DOX was next proven to be a more potent inducer of GC DAMPs emission than doxorubicin. As a result, Nano-DOX-damaged GC exhibited an enhanced ability to attract both TAM and Nano-DOX-loaded TAM. Most remarkably, Nano-DOX-damaged GC reprogrammed the TAM from a pro-GBM phenotype to an anti-GBM phenotype that suppressed GC growth. Finally, the in vivo relevance of the in vitro findings was tested in animal study. Mice bearing orthotopic human GBM xenografts were intravenously injected with Nano-DOX-loaded mouse TAM which were found releasing drug in the GBM xenografts 24h after injection. GC damage was evidenced by the induction of DAMPs emission within the xenografts and a shift of TAM phenotype was detected as well. Taken together, our results demonstrate a novel way with therapeutic potential to harness the cross-talk between GBM cells and TAM for modulation of the tumor immune microenvironment.

Fluorescent nanodiamonds enable quantitative tracking of human mesenchymal stem cells in miniature pigs.

Cell therapy is a promising strategy for the treatment of human diseases. While the first use of cells for therapeutic purposes can be traced to the 19th century, there has been a lack of general and reliable methods to study the biodistribution and associated pharmacokinetics of transplanted cells in various animal models for preclinical evaluation. Here, we present a new platform using albumin-conjugated fluorescent nanodiamonds (FNDs) as biocompatible and photostable labels for quantitative tracking of human placenta choriodecidual membrane-derived mesenchymal stem cells (pcMSCs) in miniature pigs by magnetic modulation. With this background-free detection technique and time-gated fluorescence imaging, we have been able to precisely determine the numbers as well as positions of the transplanted FND-labeled pcMSCs in organs and tissues of the miniature pigs after intravenous administration. The method is applicable to single-cell imaging and quantitative tracking of human stem/progenitor cells in rodents and other animal models as well.

Neuroprotective Effect of Nanodiamond in Alzheimer's Disease Rat Model: a Pivotal Role for Modulating NF-κB and STAT3 Signaling.

Current therapeutic approaches of Alzheimer's disease (AD) are symptomatic and of modest efficacy, and there is no available effective cure or prevention of AD; hence, the need arise to search for neuroprotective agents to combat AD. The current study aimed at investigating the neuroprotective effect of nanodiamond (ND), adamantine-based nanoparticles, in aluminum-induced cognitive impairment in rats, an experimental model of AD. AD was induced by aluminum chloride (17 mg/kg, p.o. for 6 weeks) and confirmed by Morris water maze and Y-maze behavioral tests. Biochemical and histological analyses of the hippocampus were also performed. Aluminum-treated rats showed behavioral, biochemical, and histological changes similar to those associated with AD. ND improved learning and memory and reversed histological alterations. At the molecular levels, ND mitigated the increase of hippocampal beta-amyloid (Aß42) and beta-site amyloid precursor protein cleaving enzyme-1 (BACE1) together with down-regulation of phosphorylated tau protein. It also modulated the excitatory glutamate neurotransmitter level. Furthermore, ND boosted the brain-derived neurotrophic factor (BDNF) and mitochondrial transcription factor-A (TFAM), suppressed the proinflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and curbed oxidative stress by hampering of inducible nitric oxide synthase (iNOS). Moreover, ND augmented the hippocampal levels of phosphorylated signal transducer and activator of transcription-3 (p-STAT3) and B cell leukemia/lymphoma-2 (Bcl-2) anti-apoptotic protein while diminished nuclear factor-kappaB (NF-κB) and caspase-3 (casp-3) expression. These findings indicate the protective effect of ND against memory deficits and AD-like pathological aberrations probably via modulating NF-kB and STAT3 signaling, effects mediated likely by modulating N-methyl-D-aspartate (NMDA) receptors.

Nanodiamond-Manganese dual mode MRI contrast agents for enhanced liver tumor detection.

Contrast agent-enhanced magnetic resonance (MR) imaging is critical for the diagnosis and monitoring of a number of diseases, including cancer. Certain clinical applications, including the detection of liver tumors, rely on both T1 and T2-weighted images even though contrast agent-enhanced MR imaging is not always reliable. Thus, there is a need for improved dual mode contrast agents with enhanced sensitivity. We report the development of a nanodiamond-manganese dual mode contrast agent that enhanced both T1 and T2-weighted MR imaging. Conjugation of manganese to nanodiamonds resulted in improved longitudinal and transverse relaxivity efficacy over unmodified MnCl2 as well as clinical contrast agents. Following intravenous administration, nanodiamond-manganese complexes outperformed current clinical contrast agents in an orthotopic liver cancer mouse model while also reducing blood serum concentration of toxic free Mn2+ ions. Thus, nanodiamond-manganese complexes may serve as more effective dual mode MRI contrast agent, particularly in cancer.

Fructose-Coated Nanodiamonds: Promising Platforms for Treatment of Human Breast Cancer.

Well-defined carboxyl end-functionalized glycopolymer Poly(1-O-methacryloyl-2,3:4,5-di-O-isopropylidene-ß-d-fructopyranose) (Poly(1-O-MAipFru)62) has been prepared via reversible addition-fragmentation chain transfer polymerization and grafted onto the surface of amine-functionalized nanodiamonds via a simple conjugation reaction. The properties of the nanodiamond-polymer hybrid materials ND-Poly(1-O-MAFru)62 are investigated using infrared spectroscopy, thermogravimetric analysis, dynamic light scattering, and transmission electron microscopy. The dispersibility of the nanodiamonds in aqueous solutions is significantly improved after the grafting of the glycopolymer. More interestingly, the cytotoxicity of amine-functionalized nanodiamonds is significantly decreased after decoration with the glycopolymer even at a high concentration (125 µg/mL). The nanodiamonds were loaded with doxorubicin to create a bioactive drug delivery carrier. The release of doxorubicin was faster in media of pH 5 than media of pH 7.4. The nanodiamond drug delivery systems with doxorubicin are used to treat breast cancer cells in 2D and 3D models. Although the 2D cell culture results indicate that all nanodiamonds-doxorubicin complexes are significantly less toxic than free doxorubicin, the glycopolymer-coated nanodiamonds-doxorubicin show higher cytotoxicity than free doxorubicin in the 3D spheroids after treatment for 8 days. The enhanced cytotoxicity of Poly(1-O-MAFru)62-ND-Dox in 3D spheroids may result from the sustained drug release and deep penetration of these nanocarriers, which play a role as a "Trojan Horse". The massive cell death after 8-day incubation with Poly(1-O-MAFru)62-ND-Dox demonstrates that glycopolymer-coated nanodiamonds can be promising platforms for breast cancer therapy.

Comprehensive evaluation of carboxylated nanodiamond as a topical drug delivery system.

The best strategy in the development of topical drug delivery systems may be to facilitate the permeation of drugs without any harmful effects, while staying on the skin surface and maintaining stability of the system. Nanodiamonds (NDs) play a key role with their excellent physicochemical properties, including high biocompatibility, physical adsorption, reactive oxygen species (ROS) scavenging capability, and photostabilizing activity. Z-average sizes of carboxylated ND (ND-COOH) agglutinate decreased significantly as the pH increased. Fluorescein-conjugated ND was observed only on the stratum corneum, and no sample diffused into the dermal layer even after 48 hours. Moreover, ND-COOH and ND-COOH/eugenol complex did not show significant toxic effects on murine macrophage cells. ND improved in vitro skin permeation >50% acting as a "drug reservoir" to maintain a high drug concentration in the donor chamber, which was supported by quartz crystal microbalance results. Moreover, ND-COOH could adsorb a drug amount equivalent to 80% of its own weight. A photostability study showed that ND-COOH increased the photostability ~47% with regard to rate constant of the eugenol itself. A significant decrease in ROS was observed in the ND-COOH and ND-COOH/eugenol complex compared with the negative control during intracellular ROS assay. Moreover, ROS and cupric reducing antioxidant capacity evaluation showed that ND-COOH had synergistic effects of antioxidation with eugenol. Therefore, ND-COOH could be used as an excellent topical drug delivery system with improved permeability, higher stability, and minimized safety issue.

Bone-targeted delivery of nanodiamond-based drug carriers conjugated with alendronate for potential osteoporosis treatment.

This paper describes the design of alendronate-conjugated nanodiamonds (Alen-NDs) and evaluation of their feasibility for bone-targeted delivery. Alen-NDs exhibited a high affinity to hydroxyapatite (HAp, the mineral component of bone) due to the presence of Alen. Unlike NDs (without Alen), Alen-NDs were preferentially taken up by MC3T3-E1 osteoblast-like cells, compared to NIH3T3 and HepG2 cells, suggesting their cellular specificity. In addition, NDs itself increased ALP activity of MC3T3-E1 cells, compared to control group (osteogenic medium) and Alen-NDs exhibited more enhanced ALP activity. In addition, an in vivo study revealed that Alen-NDs effectively accumulated in bone tissues after intravenous tail vein injection. These results confirm the superior properties of Alen-NDs with advantages of high HAp affinity, specific uptake for MC3T3-E1 cells, positive synergistic effect for ALP activity, and in vivo bone targeting ability. The Alen-NDs can potentially be employed for osteoporosis treatment by delivering both NDs and Alen to bone tissue.

A Chemopreventive Nanodiamond Platform for Oral Cancer Treatment.

Standard oral cancer therapy generally includes a combination of surgery with chemotherapy and/or radiotherapy. This treatment paradigm has not changed in some time. In this paper, we propose a chemopreventive nanodiamond platform for the delivery of celecoxib (Celebrex) to oral cancer lesions. This innovative platform allows for sustained drug release under physiological conditions, potentially enhancing chemopreventive efficacy of celecoxib without the physical and toxicological damage associated with conventional means of drug delivery.

Nanodiamonds coupled with 5,7-dimethoxycoumarin, a plant bioactive metabolite, interfere with the mitotic process in B16F10 cells altering the actin organization.

For the first time, we coupled reduced detonation nanodiamonds (NDs) with a plant secondary metabolite, citropten (5,7-dimethoxycoumarin), and demonstrated how this complex was able to reduce B16F10 tumor cell growth more effectively than treatment with the pure molecule. These results encouraged us to find out the specific mechanism underlying this phenomenon. Internalization kinetics and quantification of citropten in cells after treatment with its pure or ND-conjugated form were measured, and it was revealed that the coupling between NDs and citropten was essential for the biological properties of the complex. We showed that the adduct was not able to induce apoptosis, senescence, or differentiation, but it determined cell cycle arrest, morphological changes, and alteration of mRNA levels of the cytoskeletal-related genes. The identification of metaphasic nuclei and irregular disposition of ß-actin in the cell cytoplasm supported the hypothesis that citropten conjugated with NDs showed antimitotic properties in B16F10 cells. This work can be considered a pioneering piece of research that could promote and support the biomedical use of plant drug-functionalized NDs in cancer therapy.

Impairing the radioresistance of cancer cells by hydrogenated nanodiamonds.

Hydrogenated nanodiamonds (H-NDs) exhibit a negative electron affinity that confers a high reactivity with oxygen species and a positive charge in aqueous solutions. It allows electron emission from H-NDs following irradiation by photons and in consequence may enhance the effects of radiation on cancer cells. By using three human radioresistant cancer cell lines, we showed a potentialization of cytotoxicity after a co-exposure to H-NDs and irradiation; an event occurring through the induction of DNA damage and reactive oxygen species. This occurred together with a decrease in cell impedance, the activation of G1/S, an unlocking of G2 cell cycle check-points and early low cell death rate. At later stage of exposure, persistent increases in heterochromatinization, large γ-H2AX foci and ß-galactosidase activity were detected providing evidence of cells' entrance into senescence. Similar potentialization was observed with neocarzinostatin (NCS), a radiomimetic drug. This original finding underlines a wide clinical potential of H-NDs to intensify radiation effects on radio-resistant cancer cells.

Nanodiamonds coupled with plant bioactive metabolites: a nanotech approach for cancer therapy.

Nanodiamond application in biotechnological and medical fields is nowadays in continuous progress. In fact, biocompatibility, reduced dimensions and high surface chemical interaction are specific features that make nanodiamonds perfect intracellular carriers of bioactive compounds. By confocal microscopy, we confirmed that nanodiamonds were able to penetrate in cell cytoplasm but we also demonstrated how they remained embedded in nuclear membrane just exposing some little portions into nuclear area, definitively clarifying this topic. In this work, for the first time, nanodiamonds were conjugated with plant secondary metabolites, ciproten and quercetin. Moreover, since drug-loading on nanoparticles was strongly conditioned by their chemical surface, different types of nanodiamonds (oxidized, wet chemical reduced and plasma reduced) were synthesized in this work and then functionalized with plant compounds. We found that ciproten and quercetin antiproliferative effects, on human (HeLa) and murine (B16F10) tumor cells, were improved after nanodiamond conjugation. Moreover, plant molecules highly reduced their in vitro pro-oxidant, cytotoxic and pro-apoptotic activity when associated with nanodiamond. We are led to suppose that natural drug-nanodiamond adducts would act at cellular level by different molecular mechanisms with respect to plant metabolite pure forms. Finally, our results showed that chemical and structural modifications of nanodiamond surfaces influenced the bioactivity of transported drugs. According to all these evidences, this work can be considered as a promotional research to favor the use of bioactive plant molecules associated with nanodiamonds for therapeutic purposes.