Recent Advances of Using Hybrid Nanocarriers in Remotely Controlled Therapeutic Delivery

Multifunctional temozolomide-loaded lipid superparamagnetic nanovectors: dual targeting and disintegration of glioblastoma spheroids by synergic chemotherapy and hyperthermia treatment

Aiming at finding new solutions for fighting glioblastoma multiforme, one of the most aggressive and lethal human cancer, here an in vitro validation of multifunctional nanovectors for drug delivery and hyperthermia therapy is proposed. Hybrid magnetic lipid nanoparticles have been fully characterized and tested on a multi-cellular complex model resembling the tumor microenvironment. Investigations of cancer therapy based on a physical approach (namely hyperthermia) and on a pharmaceutical approach (by exploiting the chemotherapeutic drug temozolomide) have been extensively carried out, by evaluating its antiproliferative and pro-apoptotic effects on 3D models of glioblastoma multiforme. A systematic study of transcytosis and endocytosis mechanisms has been moreover performed with multiple complimentary investigations, besides a detailed description of local temperature increments following hyperthermia application. Finally, an in-depth proteomic analysis corroborated the obtained findings, which can be summarized in the preparation of a versatile, multifunctional, and effective nanoplatform able to overcome the blood-brain barrier and to induce powerful anti-cancer effects on in vitro complex models.

Effect of PEGylation on the biological properties of cationic carbosilane dendronized gold nanoparticles

Heterofunctionalized gold nanoparticles (AuNPs) were obtained in a one pot reaction of gold precursor with cationic carbosilane dendrons (first to third generations, 1-3G) and (polyethylene)glycol (PEG) ligands in the presence of a reducing agent. The final dendron/PEG proportion on AuNPs depends on the initial dendron/PEG ratio (3/1, 1/1, 1/3) and dendron generation. AuNPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), ultraviolet spectroscopy (UV-VIS), thermogravimetric analysis (TGA), nuclear magnetic resonance (¹H NMR) and zeta potential (ZP). Several assays have been carried out to determine the relevance of PEG/dendron ratio and dendron generation in the biomedical properties of PEGylated AuNPs and the results have been compared with those obtained for non-PEGylated AuNPs. Finally, analyses of PEG recognition by anti-PEG antibodies were carried out. In general, haemolysis, platelet aggregation and toxicity were reduced after PEGylation of AuNPs, the effect being dependent on dendron generation and dendron/PEG ratio. Dendron generation determines the exposure of PEG ligand and the interaction of this ligand with AuNPs environment. On the other hand, increasing PEG proportion diminishes toxicity but also favors interaction with antibodies.

Oxidation-Responsive Nanoassemblies for Light-Enhanced Gene Therapy

Microenvironment-responsive supramolecular assemblies have attracted great interest in the biomedical field due to their potential applications in controlled drug release. In this study, oxidation-responsive supramolecular polycationic assemblies named CPAs are prepared for nucleic acid delivery via the host-guest interaction of β-cyclodextrin based polycations and a ferrocene-functionalized zinc tetraaminophthalocyanine core. The reactive oxygen species (ROS) can accelerate the disassembly of CPA/pDNA complexes, which would facilitate the release of pDNA in the complexes and further benefit the subsequent transfection. Such improvement in transfection efficiency is proved in A549 cells with high H₂ O₂ concentration. Interestingly, the transfection efficiencies mediated by CPAs are also different in the presence or absence of light in various cell lines such as HEK 293 and 4T1. The single oxygen (¹ O₂ ), produced by photosensitizers in the core of CPAs under light, increases the ROS amount and accelerates the disassembly of CPAs/pDNA complexes. In vitro and in vivo studies further illustrate that suppressor tumor gene p53 delivered by CPAs exhibits great antitumor effects under illumination. This work provides a promising strategy for the design and fabrication of oxidation-responsive nanoassemblies with light-enhanced gene transfection performance.

Theranostic nanozyme: Silk fibroin based multifunctional nanocomposites to combat oxidative stress

Multifunctional nanomaterials integrating therapeutic and imaging modalities in one platform have opened a new era in the present therapeutic strategies. In the present study, a multifunctional silk fibroin-based carrier has been designed for the delivery of antioxidant and imaging agents. One-step desolvation method was used to prepare sulforaphane (antioxidant drug) loaded silk fibroin nanoparticles (SFSNPs). These anionic SFSNPs were further coupled with cationic cerium oxide nanoparticles (CeNPs) and PEI passivated carbon dots (CDs) to form self-assembled CeNP-CD@SFSNPs nanocomposites. CDs were synthesized from mulberry leaves (Morus indica) as green source of carbon and bPEI as a passivating agent to get positively charged CDs. The CDs functioned as molecular probes by emitting green fluorescence while the presence of CeNPs augmented the antioxidant potential due to their unique redox property. Time-dependent in vitro release of sulforaphane was fast in acidic pH than under normal physiological conditions. Cytotoxicity studies were performed on L132 normal epithelial lung cell lines and A549 lung cancer cell lines to analyze the toxicity of the nanocomposites. Green fluorescence from the CDs facilitated in fluorescence microscopic imaging and cellular uptake studies. ROS scavenging capability was analyzed by exposing cells to H₂O₂ stress using flow cytometry and DCFH-DA staining. Overall, the synthesized CeNP-CD@SFSNPs nanocomposites efficiently reduced ROS levels by simultaneously enabling imaging of the cells. Thus, this CeNP-CD@SFSNPs nanocomposite could be a potential candidate for simultaneous imaging and drug delivery against oxidative stress.

The Horizon of the Emulsion Particulate Strategy: Engineering Hollow Particles for Biomedical Applications

With their hierarchical structures and the substantial surface areas, hollow particles have gained immense research interest in biomedical applications. For scalable fabrications, emulsion-based approaches have emerged as facile and versatile strategies. Here, the recent achievements in this field are unfolded via an "emulsion particulate strategy," which addresses the inherent relationship between the process control and the bioactive structures. As such, the interior architectures are manipulated by harnessing the intermediate state during the emulsion revolution (intrinsic strategy), whereas the external structures are dictated by tailoring the building blocks and solidification procedures of the Pickering emulsion (extrinsic strategy). Through integration of the intrinsic and extrinsic emulsion particulate strategy, multifunctional hollow particles demonstrate marked momentum for label-free multiplex detections, stimuli-responsive therapies, and stem cell therapies.

X-ray-Controlled Bilayer Permeability of Bionic Nanocapsules Stabilized by Nucleobase Pairing Interactions for Pulsatile Drug Delivery

The targeted and sustained drug release from stimuli-responsive nanodelivery systems is limited by the irreversible and uncontrolled disruption of the currently used nanostructures. Bionic nanocapsules are designed by cross-linking polythymine and photoisomerized polyazobenzene (PETAzo) with adenine-modified ZnS (ZnS-A) nanoparticles (NPs) via nucleobase pairing. The ZnS-A NPs convert X-rays into UV radiation that isomerizes the azobenzene groups, which allows controlled diffusion of the active payloads across the bilayer membranes. In addition, the nucleobase pairing interactions between PETAzo and ZnS-A prevent drug leakage during their in vivo circulation, which not only enhances tumor accumulation but also maintains stability. These nanocapsules with tunable permeability show prolonged retention, remotely controlled drug release, enhanced targeted accumulation, and effective antitumor effects, indicating their potential as an anticancer drug delivery system.

Light-Induced Redox-Responsive Smart Drug Delivery System by Using Selenium-Containing Polymer@MOF Shell/Core Nanocomposite

Rational design of controllable drug release systems is important for tumor treatments due to the nonspecific toxicity of many chemotherapeutics. Herein, laser or light responsive pharmaceutical delivery nanoparticles are designed, by taking the advantages of redox responsive selenium (Se) substituted polymer as shell and photosensitive porphyrin zirconium metal-organic frameworks (MOF) as core. In detail, redox cleavable di-(1-hydroxylundecyl) selenide (DH-Se), biocompatible poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) are randomly polymerized to form poly(DH-Se/PEG/PPG urethane), which is used to coat the reactive oxygen species' (ROS) producible porous porphyrin zirconium metal organization formulation (PCN-224 MOF) to form the final poly(DH-Se/PEG/PPG urethane)@MOF shell-core nanoparticle with spherical shape by emulsion approach. Interestingly, poly(DH-Se/PEG/PPG urethane)@MOF nanoparticles with loading of chemotherapeutic doxorubicin (DOX) experience a fast and controllable release, which can realize the combination of chemotherapy and photodynamic therapy upon irradiation with laser light, due to the light-triggered ROS production by MOF which further causes the cleavage of poly(DH-Se/PEG/PPG urethane) polymer chain and the release of encapsulated DOX. To the best of the authors' knowledge, this is the first design of utilizing MOF and selenium substituted polymer as controllable drug release carriers, which might be beneficial for precise chemotherapy and photodynamic therapy combination.

Synthesis of porphyrin-conjugated silica-coated Au nanorods for synergistic photothermal therapy and photodynamic therapy of tumor

Synergistic therapy of tumor has attracted the attention of an increasing number of researchers because of its higher efficiency compared to single therapy. Herein, 4-carboxyphenyl porphyrin-conjugated silica-coated gold nanorods (AuNR@SiO₂-TCPP) were synthesized. The synergistic treatment of photothermal therapy and photodynamic therapy on A549 cancer was researched in vivo and in vitro. In the AuNR@SiO₂-TCPP, Au NRs and TCPP act as photothermal agent and photosensitizer, respectively. The temperature of the AuNR@SiO₂-TCPP (0.11 nmol L^-1) rises to 56.8 °C for 10 min under the illumination of 808 nm laser (2 Wcm^-2). In MTT assays, the viability of A549 cancer cell treated with AuNR@SiO₂-TCPP (100 μg ml^-1) is only 21%. In animal experiments, the relative tumor volumes in mice receiving AuNR@SiO₂-TCPP (5 mg kg^-1) with 660 and 808 nm irradiations were significantly inhibited and the average value is decreased to 0.78 while the average value of the control group is increased to 7.2. These results demonstrate that the AuNR@SiO₂-TCPP is a potential nanomedicine against tumor for clinical application in the near future.

Microgels in biomaterials and nanomedicines

Microgels are colloidal particles with crosslinked polymer networks and dimensions ranging from tens of nanometers to micrometers. Specifically, smart microgels are fascinating capable of responding to biological signals in vivo or remote triggers and making the possible for applications in biomaterials and biomedicines. Therefore, how to fundamentally design microgels is an urgent problem to be solved. In this review, we put forward our important fundamental opinions on how to devise the intelligent microgels for cancer therapy, biosensing and biological lubrication. We focus on the design ideas instead of specific implementation process by employing reverse synthesis analysis to programme the microgels at the original stage. Moreover, special insights will be, for the first time, as far as we know, dedicated to the particles completely composed of DNA or proteins into microgel systems. These are discussed in detail in this review. We expect to give readers a broad overview of the design criteria and practical methodologies of microgels according to the application fields, as well as to propel the further developments of highly interesting concepts and materials.

Hybrid Nanogels: Stealth and Biocompatible Structures for Drug Delivery Applications

Considering nanogels, we have focused our attention on hybrid nanosystems for drug delivery and biomedical purposes. The distinctive strength of these structures is the capability to join the properties of nanosystems with the polymeric structures, where versatility is strongly demanded for biomedical applications. Alongside with the therapeutic effect, a non-secondary requirement of the nanosystem is indeed its biocompatibility. The importance to fulfill this aim is not only driven by the priority to reduce, as much as possible, the inflammatory or the immune response of the organism, but also by the need to improve circulation lifetime, biodistribution, and bioavailability of the carried drugs. In this framework, we have therefore gathered the hybrid nanogels specifically designed to increase their biocompatibility, evade the recognition by the immune system, and overcome the self-defense mechanisms present in the bloodstream of the host organism. The works have been essentially organized according to the hybrid morphologies and to the strategies adopted to fulfill these aims: Nanogels combined with nanoparticles or with liposomes, and involving polyethylene glycol chains or zwitterionic polymers.

Photo-induced hydrogen-bonding complexes for drug periodic release

A convenient approach for periodic drug release was accomplished through photo-induced hydrogen-bonding complexation, and then by further disruption upon heating.

Codelivery of Hydrophobic and Hydrophilic Drugs by Graphene-Decorated Magnetic Dendrimers

In this study, a nanocarrier was prepared for the codelivery of a hydrophilic drug (doxorubicin) and a hydrophobic drug (curcumin) to cancer cells. In this nanocarrier, the edges of graphene oxide sheets were decorated with a magnetic-functionalized polyamidoamine dendrimer with hydrazone groups at the end of the polymer. The edge functionalization of graphene sheets not only improved the solubility and dispersibility of graphene sheets but also imparted the magnetic properties to the nanocarrier. The resulting nanocarrier was loaded with doxorubicin through the covalent linkage and curcumin through π-π stacking. The nanocarrier showed a pH-sensitive release for both drugs, and the drug release behavior was also improved by the coimmobilization of both drugs. The cytotoxicity assay of nanocarrier showed low toxicity toward MCF-7 cell compared to unmodified graphene oxide, which was attributed to the presence of a magnetic dendrimer. Besides, the drug-loaded nanocarrier was highly toxic for cells even more than for free drugs. The cellular uptake images revealed higher drug internalization for coloaded nanocarrier than for the nanocarrier loaded with one drug alone. All of the results showed that the codelivery of curcumin and doxorubicin in the presence of the nanocarrier was more effective in chemotherapy than the nanocarrier loaded with one drug.

Bioresponsive-controlled release of methylene blue from magnetic mesoporous silica from the electrochemical detection of telomerase activity

An electrochemical sensing platform was designed to monitor telomerase activity in HeLa cells, using bioresponsively controlled cargo release from magnetic mesoporous silica nanocontainers (MMSNs). The aminated MMSNs were first synthesized by a wet-chemistry method, then methylene blue (indicator) molecules were loaded into the pores with the aid of specifically designed wrapping DNA strands, and then the wrapping DNA-gated MMSNs were immobilized on a magnetic removable screen-printing carbon electrode. Upon target telomerase and dNTP introduction into the detection cell, the wrapping DNA strands on the MMSNs were prolonged to form rigid hairpin-like DNA structures, thus resulting in the dissociation of wrapping DNA strands from the MMSNs. Thereafter, the loaded methylene blue with redox activity was released out from the pores, thereby causing the increase in the electrochemical signal relative to the background signal. Under optimal conditions, an MMSN-based sensing system exhibited good voltammetric responses toward target telomerase activity within the dynamic linear range of 50-5000 cells per mL at a detection limit of 12 cells per mL in the HeLa extract. The reproducibility and generality of our strategy were acceptable by using somatic tumor cell lines. In addition, the inhibition effect of this system was also evaluated by using 3'-azido-3'-deoxythymidine as a telomerase inhibitor, receiving good results in this screening research.

Folate-conjugated, mesoporous silica functionalized boron nitride nanospheres for targeted delivery of doxorubicin

Biomedical application of boron nitride (BN) nanomaterials has recently attracted considerable attentions. BN nanospheres (BNNS) could safely deliver anti-cancer drug into tumor cells, which makes them potential nanocarrier for cancer therapy. However, the poor dispersity in physiological environments and low drug loading capacity severely limit their further applications. Herein, we developed a novel drug delivery system based on folate-conjugated mesoporous silica (MS)-functionalized BNNS (BNMS-FA). Dispersity and drug loading capacity of BNNS were highly improved by MS modification. BNMS-FA complexes were nontoxic up to a concentration of 100 μg/mL, and could be specifically internalized by HeLa and MCF-7 cells via folate receptor-mediated endocytosis. Doxorubicin (DOX) could be loaded onto BNMS-FA complexes with high efficiency via π-π stacking and hydrogen bonding, and showed a sustained release pattern under different pH conditions. BNMS-FA/DOX complexes exhibited superior drug internalization and antitumor efficacy over free DOX, BNNS/DOX and BNMS/DOX complexes, which were considered promising for targeted cancer therapy.

Amino acid modified [70] fullerene derivatives with high radical scavenging activity as promising bodyguards for chemotherapy protection

Despite the great efforts for tumor therapy in the last decades, currently chemotherapy induced toxicity remains a formidable problem for cancer patients, and it usually prohibits the cancer therapy from successful completion due to severe side effects. In general, the main side effects of chemotherapeutic agents are from the as-produced reactive oxygen species (ROS) that not only harm the tumor cells but also damage the patients’ organs. Here we report the application of amino acid derivatives of fullerene (AADF) in the chemotherapy which strongly scavenge the excess ROS to protect the tested mice against the chemotherapy-induced hepatotoxicity and cardiotoxicity. Two amino acids, i.e., L-lysine and β-alanine were separately employed to chemically modify C₇₀ fullerene, and L-lysine derivative of fullerene (C₇₀-Lys) exhibits superior radical scavenging activity to β-alanine derivative of C₇₀ (C₇₀-Ala). As expected, C₇₀-Lys show much better protective effect than C₇₀-Ala against the chemotherapy injuries in vivo, which is verified by various histopathological, haematological examinations and antioxidative enzyme studies. Moreover, the L-glutathione level is increased and the cytochrome P-450 2E1 expression is inhibited. They are potentially developed as promising bodyguards for chemotherapy protection.

PLA-PEG-FA NPs for drug delivery system: Evaluation of carrier micro-structure, degradation and size-cell proliferation relationship

In this paper, the micro-structure of amphiphilic copolymer Polylactic acid-Polyethylene glycol-Folate (PLA-PEG-FA) was studied firstly by a differential scanning calorimetry (DSC). During the process of nanoparticles (NPs) preparation, we found good inter-structure consistency of polymer was the precondition for forming into stable NPs, and those with micro-phase separation structure were prepared of NPs within limits. Hemolytic test and CCK-8 assay results demonstrated the biotoxicity of both NPs and whose leaching liquor was far below related toxicity standards. Two kinds of cell, human breast cancer cell line (MCF-7) and human umbilical vein endothelial cells (EC), showed different manners in test of NPs size-cell proliferation relationship, respectively. Monitored by a nuclear magnetic resonance (NMR) and a gel permeation chromatography (GPC), the degradation behavior of NPs in aqueous solution indicated amide bond break more difficultly than ester bond, and FA classic proton peak disappeared in the third week, meanwhile lactic acid (LA) unit number became 25% of the initial. Finally the NPs was completely degraded in the eighth week. In the whole process, NPs underwent a change from compact to loose state. We hope these results will benefit to improve design of drug delivery system in nanomedicine, which could offer the selection rule for amphiphilic polymer NPs on material and size.

Self-Assembly and Applications of Amphiphilic Hybrid POSS Copolymers

Understanding the mechanism of molecular self-assembly to form well-organized nanostructures is essential in the field of supramolecular chemistry. Particularly, amphiphilic copolymers incorporated with polyhedral oligomeric silsesquioxanes (POSSs) have been one of the most promising materials in material science, engineering, and biomedical fields. In this review, new ideas and research works which have been carried out over the last several years in this relatively new area with a main focus on their mechanism in self-assembly and applications are discussed. In addition, insights into the unique role of POSSs in synthesis, microphase separation, and confined size were encompassed. Finally, perspectives and challenges related to the further advancement of POSS-based amphiphilics are discussed, followed by the proposed design considerations to address the challenges that we may face in the future.

Strontium functionalized scaffold for bone tissue engineering

Drug functionalized scaffolds are currently being employed to improve local delivery of osteoprotective drugs with the aim of reducing their loading dose as well as unwanted systemic complications. In this study we tested a poly-(ε) caprolactone (PCL)-laponite-strontium ranelate (SRA) composite scaffold (PLS3) for its abilities to support growth and osteogenic differentiation of human marrow derived stromal stem cells (hMSC). The in vitro experiments showed the PLS3 scaffold supported cell growth and osteogenic differentiation. The in vivo implantation of hMSC seeded PLS3 scaffold in immunocompromised mice revealed vascularized ectopic bone formation. PLS3 scaffolds can be useful in bone regenerative applications in the fields of orthopaedics and dentistry.

Biodegradable polyester unimolecular systems as emerging materials for therapeutic applications

Unimolecular micelles, as a class of single-molecular micelles, are structurally stable regardless of their concentrations or alterations of the outer environment such as pH, temperature, ion strength etc. in comparison with conventional polymeric micelles. Polyester unimolecular micelles are extensively applied in bio-medical fields because of their stability, biocompatibility, biodegradability, structural-controllabilty etc. In this review, the most recent developments in polyester unimolecular micelle designs in terms of Boltorn polymer H40 core, cyclodextrin, dendrimer or dendrimer-like polymer, or polyhedral oligomeric silsesquioxane (POSS) based polyester unimolecular micelles are presented. The significance and application in biomedical fields including drug delivery, bio-imaging and theranostics are also classified in this review. Finally, the remaining challenges and future perspectives for further development of unimolecular micelles as therapeutic materials are also discussed.

Polymeric Encapsulation of Turmeric Extract for Bioimaging and Antimicrobial Applications

As a herb of the ginger family, the turmeric plant has been used as spice and colorant in the Oriental countries. The rhizome part of the plant is rich in curcumin, which has been proven to be the main ingredient responsible for turmeric's biological effects. Most research endeavors have been upon the investigation of pharmaceutical activities of curcumin, yet the fluorescence of curcumin is a bit far from well-studied. The major drawbacks associated with curcumin are its poor aqueous solubility and low stability. In this communication, the encapsulation of fluorescent turmeric extract into polymeric nanoparticles (NPs) for bioimaging and antibacterial applications is reported. Through poly(d,l-lactic-co-glycolic acid) (PLGA) encapsulation, solubility of curcumin is greatly increased, and the biodegradable nature of PLGA further enhances the biocompatibility of curcumin. These Cur-PLGA NPs are successfully demonstrated to be efficient fluorescence probes for bioimaging, and promising for antibacterial application.

Copper-polyaniline nanocomposite: Role of physicochemical properties on the antimicrobial activity and genotoxicity evaluation

Copper nanoparticles (Cu NPs) have proven to own excellent antimicrobial efficacy, but the problems of easy oxidation and aggregation limit their practical application. Here, nanocomposite based on polyaniline (PANI) and Cu NPs solved this problem and brought additional physicochemical properties that are markedly advantageous for antimicrobial applications. Current work exploits this potential, to examine its time- and concentration-dependent antimicrobial activity, employing E. coli, S. aureus, and C. albicans as a model microbial species. Regarding the presence of polaronic charge carriers in the fibrous polyaniline network, effects of Cu NPs' size and their partially oxidized surfaces (the data were confirmed by HRTEM, FESEM, XRD, Raman and XPS analysis), as well as rapid copper ions release, Cu-PANI nanocomposite showed efficient bactericidal and fungicidal activities at the concentrations ≤1 ppm, within the incubation time of 2 h. Beside the quantitative analysis, the high levels of cellular disruption for all tested microbes were evidenced by atomic force microscopy. Moreover, the minimum inhibitory and bactericidal concentrations of the Cu-PANI nanocomposite were lower than those reported for other nanocomposites. Using such low concentrations is recognized as a good way to avoid its toxicity toward the environment. For this purpose, Cu-PANI nanocomposite is tested for its genotoxicity and influence on the oxidative status of the human cells in vitro.

Recent Overviews in Functional Polymer Composites for Biomedical Applications

Composite materials are considered as an essential part of our daily life due to their outstanding properties and diverse applications. Polymer composites are a widespread class of composites, characterized by low cost, facile processing methods, and varied applications ranging from daily-use issues to highly complicated electronics and advanced medical combinations. In this review, we focus on the most important fabrication techniques for bioapplied polymer composites such as electrospinning, melt-extrusion, solution mixing, and latex technology, as well as in situ methods. Additionally, significant and recent advances in biomedical applications are spotlighted, such as tissue engineering (including bone, blood vessels, oral tissues, and skin), dental resin-based composites, and wound dressing.

Polymeric Janus Nanoparticles: Recent Advances in Synthetic Strategies, Materials Properties, and Applications

Polymeric Janus nanoparticles with two sides of incompatible chemistry have received increasing attention due to their tunable asymmetric structure and unique material characteristics. Recently, with the rapid progress in controlled polymerization combined with novel fabrication techniques, a large array of functional polymeric Janus particles are diversified with sophisticated architecture and applications. In this review, the most recently developed strategies for controlled synthesis of polymeric Janus nanoparticles with well-defined size and complex superstructures are summarized. In addition, the pros and cons of each approach in mediating the anisotropic shapes of polymeric Janus particles as well as their asymmetric spatial distribution of chemical compositions and functionalities are discussed and compared. Finally, these newly developed structural nanoparticles with specific shapes and surface functions orientated applications in different domains are also discussed, followed by the perspectives and challenges faced in the further advancement of polymeric Janus nanoparticles as high performance materials.

Surface grafting of rare-earth ions doped hydroxyapatite nanorods (HAp:Ln(Eu/Tb)) with hydrophilic copolymers based on ligand exchange reaction: Biological imaging and cancer treatment

Rare-earth ions doped hydroxyapatite nanoparticles (HAp:Ln NPs) have demonstrated to be very promising candidates for biological imaging applications owing to their small size and chemical compositions similar to bone. However, these HAp:Ln NPs with controllable size and morphology should be prepared under hydrothermal treatment with hydrophobic molecules as the protective layers. The hydrophobic nature of these luminescent HAp:Ln NPs largely impeded their applications in biomedical fields. In this study, a novel and effective strategy has been developed for the surface modification of HAp:Ln nanorods through the combination of surface ligand exchange reaction and reversible-addition fragmentation chain transfer (RAFT) polymerization using 2-methacryloyloxyethyl phosphorylcholine (MPC) and itaconic acid (IA) as the monomers. Herein, a small molecule adenosine 5'-monophosphate disodium salt (AMP) that contains a phosphate group and two hydroxyl groups was used to displace the hydrophobic oleic acid on pristine HAp NPs through surface ligand exchange reaction owing to its stronger interaction with HAp NPs. On the other hand, the MPC and IA were introduced on HAp NPs through RAFT polymerization after the chain transfer agent was immobilized on the HAp NPs through the esterification reaction. The poly(IA-MPC) could not only endow the high water dispersibility but also be used for loading anticancer agent cisplatin (CDDP) through coordination interaction. To evaluate their potential biomedical applications, the cell uptake behavior, drug loading capacity and release behavior as well as cell viability of HAp:Ln-AMP-poly(IA-MPC) polymeric composites were examined. We demonstrated that the method developed in this work is very effective for introduction of functional polymers onto HAp:Ln nanorods. The HAp:Ln-AMP-poly(IA-MPC) composites are promising for cell imaging and controlled delivery of CDDP.

Pectin-guar gum-zinc oxide nanocomposite enhances human lymphocytes cytotoxicity towards lung and breast carcinomas

Pectin-guar gum-zinc oxide (PEC-GG-ZnO) nanocomposite was prepared by precipitation technique. The composite was characterized by using FT-IR, XRD, HRTEM, SAED, EDS, and SEM. TEM images showed the hexagonal shape of nanocomposite with the size range of 50-70 nm. Further, PEC-GG-ZnO was used as an immunomodulator for the first time to improve the cancer cells killing capabilities of human peripheral-blood lymphocytes (PBL). The lymphocyte proliferation assay proved the immunostimulatory property of the PEC-GG-ZnO which increased with the increase in concentration (25 μg/ml to 200 μg/ml). ELISA detection confirmed a significant increase in the release of IFN-γ, IL-2 and TNF-α cytokines and flow cytometry analysis revealed enhanced expression of CD3, CD8, and CD56 after treating PBL with PEC-GG-ZnO as compared to PEC and GG treatment. Moreover, we also found that nanocomposite pretreated human PBL displayed enhanced cytotoxicity towards lung (A549) and breast carcinoma (MCF-7) cells as compared to untreated PBL. The microcytotoxicity assay also demonstrated that with increase in effector: target ratios from 2.5:1 to 20:1, there was an increase in the cancer cell death. Taken together, the current data corroborates the immunostimulatory activities of PEC-GG-ZnO, a novel nanocomposite, hence it can serve as a promising cancer therapeutic agent.

Biofunctionalized peptide nanofiber-based composite scaffolds for bone regeneration

Bone tissue had moderate self-healing capabilities, but biomaterial scaffolds were required for the repair of some defects such as large bone defects. Peptide nanofiber scaffolds demonstrated important potential in regenerative medicine. Functional modification and controlled release of signal molecules were two significant approaches to increase the bioactivity of biofunctionalized peptide nanofiber scaffolds, but peptide scaffolds were limited by insufficient mechanical strength. Thus, it was necessary to combine peptide scaffolds with other materials including polymers, hydroxyapatite, demineralized bone matrix (DBM) and metal materials based on the requirement of different bone defects. As the development of peptide-based composite scaffolds continued to evolve, ultimate translation to the clinical environment may allow for improved therapeutic outcomes for bone repair.

Synthesis, characterization and antitumor properties of selenium nanoparticles coupling with ferulic acid

Selenium nanoparticles (Se NPs) attract a lot of attention as potential cancer therapeutic agents. However, the antitumor activities of pure Se NPs are poor, and some modifiers are needed to enhance the activities. In the present study, we prepared Ferulic Acid (FA)-modified selenium nanoparticles in a facile synthetic approach. The obtained FA-Se NPs were characterized using transmission electron microscope (TEM), dynamic light scattering (DLS), ultraviolet-visible spectrophotometer (UV-VIS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Energy dispersive X-ray (EDX) spectroscopy. In vitro antitumor effects of FA, Se NPs and FA-Se NPs in HepG-2 cells were examined by methyl thiazolyl tetrazolium (MTT) assay. It showed that FA-Se NPs effectively inhibited the growth of HepG-2 cells with IC₅₀ value of 11.57 ± 3.6 μg/ml, while the value of Se NPs was >100 μg/ml. In addition, FA behaves no obvious antitumor effects at high concentrations up to 100 μg/ml. In order to investigate the antitumor mechanism of FA-Se NPs, fluorescence morphological examination and Annexin V-FITC/PI staining analysis were performed to observe the apoptosis of HepG-2 cells induced by FA-Se NPs. Meanwhile, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) levels and caspase-3 and -9 activities were detected. The results revealed that FA-Se NPs induced intracellular ROS generation and MMP disruption by finally activating caspase-3/9 to trigger HepG-2 cells apoptosis through mitochondrial pathway. Further investigation on the interactions of FA-Se NPs with calf thymus DNA (ctDNA) indicated that the antitumor activities may be associated with the DNA-binding properties of FA-Se NPs.

Investigation of adhesive interactions in the specific targeting of Triptorelin-conjugated PEG-coated magnetite nanoparticles to breast cancer cells

The understanding of adhesive interaction at the nanoscale between functionalized nanoparticles and biological cells is of great importance to develop effective theranostic nanocarriers for targeted cancer therapy. Here, we report a combination of experimental and computational approaches to evaluate the adhesion between Triptorelin (a Luteinizing Hormone-Releasing Hormone (LHRH) agonist)-conjugated poly-(ethylene glycol) (PEG)-coated magnetite nanoparticles (Triptorelin-MNPs) and breast cells. The adhesion forces between Triptorelin-MNPs and normal/cancerous breast cells are obtained using atomic force microscopy. The corresponding work of adhesion is then estimated using Johnson-Kendall-Roberts model. Our results demonstrate that Triptorelin-MNPs have a fourteen-fold greater work of adhesion to breast cancer cells than to normal breast cells. In addition, the work of adhesion between Triptorelin-MNPs and breast cancer cells is found to be three times more than that between unmodified MNPs and breast cancer cells. Hence, the experimental observation indicates that Triptorelin ligands facilitate the specific targeting of breast cancer cells. Furthermore, molecular dynamics simulations are performed to investigate the molecular origins of the adhesive interactions. The simulations reveal that the interactions between molecules (e.g. Triptorelin and PEG) and LHRH receptors are dominated by van der Waals energies, while the interactions of these molecules with cell membrane are dominated by electrostatic interactions. Moreover, both experimental and computational results reveal that PEG serves as an effective coating that enhances adhesive interactions to breast cancer cells that over-express LHRH receptors, while reduces the adhesion to normal breast cells. Our results highlight the potential to develop Triptorelin-MNPs into tumor-specific MRI contrast agents and drug carriers.

STATEMENT OF SIGNIFICANCE

Systematic investigation of adhesive interactions between functionalized nanoparticles and cancer cells is of great importance in developing effective theranostic nanocarriers for targeted cancer therapy. Herein, we use a combination of atomic force microscopy technique and molecular dynamics simulations approach to explore the adhesive interactions at the nanoscale between Triptorelin-conjugated polyethylene glycol (PEG)-coated magnetite nanoparticles and normal/cancerous breast cells. This study characterizes and quantifies the work of adhesion, as well as adhesion forces, at the nanocarrier/cell interfaces, unravels the molecular origins of adhesive interactions and highlights the effectiveness of PEG coatings and Triptorelin ligands in the specific targeting of breast cancer cells. Our findings expand the fundamental understanding of nanoparticle/cell adhesion and provide guidelines for the design of more rational nanocarriers.

Synthesis of Au@polymer nanohybrids with transited core-shell morphology from concentric to eccentric Emoji-N or Janus nanoparticles

The combination of multifunctionality and synergestic effect displayed by hybrid nanoparticles (NPs) has been revealed as an effective stratagem in the development of advanced nanostructures with unique biotechnology and optoelectronic applications. Although important work has been devoted, the demand of facile, versatile and efficient synthetic approach remains still challenging. Herein, we report a feasible and innovative way for polymer-shell assembling onto gold nanoparticles in competitive conditions of hydrophobic/hydrophilic feature and interfacial energy of components to generate core-shell nanohybrids with singular morphologies. The fine control of reaction parameters allows a modulated transformation from concentric to eccentric nanostructure-geometries. In this regard, a rational selection of the components and solvent ratio guarantee the reproducibility and efficiency on hybrid-nanoassembly. Furthermore, the simplicity of the synthetic approach offers the possibility to obtain asymmetric Janus NPs and new morphologies (quizzical-aspheric polymer-shell, named Emoji-N-hybrids) with adjustable surface-coating, leading to new properties and applications that are unavailable to their symmetrical or single components.

Biomimetic polyurethane/TiO2 nanocomposite scaffolds capable of promoting biomineralization and mesenchymal stem cell proliferation

Scaffolds with extracellular matrix-like fibrous morphology, suitable mechanical properties, biomineralization capability, and excellent cytocompatibility are desired for bone regeneration. In this work, fibrous and degradable poly(ester urethane)urea (PEUU) scaffolds reinforced with titanium dioxide nanoparticles (nTiO2) were fabricated to possess these properties. To increase the interfacial interaction between PEUU and nTiO2, poly(ester urethane) (PEU) was grafted onto the nTiO2. The scaffolds were fabricated by electrospinning and exhibited fiber diameter of <1μm. SEM and EDX mapping results demonstrated that the PEU modified nTiO2 was homogeneously distributed in the fibers. In contrast, severe agglomeration was found in the scaffolds with unmodified nTiO2. PEU modified nTiO2 significantly increased Young's modulus and tensile stress of the PEUU scaffolds while unmodified nTiO2 significantly decreased Young's modulus and tensile stress. The greatest reinforcement effect was observed for the scaffold with 1:1 ratio of PEUU and PEU modified nTiO2. When incubating in the simulated body fluid over an 8-week period, biomineralization was occurred on the fibers. The scaffolds with PEU modified nTiO2 showed the highest Ca and P deposition than pure PEUU scaffold and PEUU scaffold with unmodified nTiO2. To examine scaffold cytocompatibility, bone marrow-derived mesenchymal stem cells were cultured on the scaffold. The PEUU scaffold with PEU modified nTiO2 demonstrated significantly higher cell proliferation compared to pure PEUU scaffold and PEUU scaffold with unmodified nTiO2. The above results demonstrate that the developed fibrous nanocomposite scaffolds have potential for bone tissue regeneration.