Novel bilayer bacterial nanocellulose scaffold supports neocartilage formation in vitro and in vivo

Tissue engineering provides a promising alternative therapy to the complex surgical reconstruction of auricular cartilage by using ear-shaped autologous costal cartilage. Bacterial nanocellulose (BNC) is proposed as a promising scaffold material for auricular cartilage reconstruction, as it exhibits excellent biocompatibility and secures tissue integration. Thus, this study evaluates a novel bilayer BNC scaffold for auricular cartilage tissue engineering. Bilayer BNC scaffolds, composed of a dense nanocellulose layer joined with a macroporous composite layer of nanocellulose and alginate, were seeded with human nasoseptal chondrocytes (NC) and cultured in vitro for up to 6 weeks. To scale up for clinical translation, bilayer BNC scaffolds were seeded with a low number of freshly isolated (uncultured) human NCs combined with freshly isolated human mononuclear cells (MNC) from bone marrow in alginate and subcutaneously implanted in nude mice for 8 weeks. 3D morphometric analysis showed that bilayer BNC scaffolds have a porosity of 75% and mean pore size of 50 ± 25 μm. Furthermore, endotoxin analysis and in vitro cytotoxicity testing revealed that the produced bilayer BNC scaffolds were non-pyrogenic (0.15 ± 0.09 EU/ml) and non-cytotoxic (cell viability: 97.8 ± 4.7%). This study demonstrates that bilayer BNC scaffolds offer a good mechanical stability and maintain a structural integrity while providing a porous architecture that supports cell ingrowth. Moreover, bilayer BNC scaffolds provide a suitable environment for culture-expanded NCs as well as a combination of freshly isolated NCs and MNCs to form cartilage in vitro and in vivo as demonstrated by immunohistochemistry, biochemical and biomechanical analyses.     

Transferrin-conjugated magnetic silica PLGA nanoparticles loaded with doxorubicin and paclitaxel for brain glioma treatment

The effective treatment of malignant brain glioma is hindered by the poor transport across the blood–brain barrier (BBB) and the low penetration across the blood-tumor barrier (BTB). In this study, transferrin-conjugated magnetic silica PLGA nanoparticles (MNP-MSN-PLGA-Tf NPs) were formulated to overcome these barriers. These NPs were loaded with doxorubicin (DOX) and paclitaxel (PTX), and their anti-proliferative effect was evaluated in vitro and in vivo. The in vitro cytotoxicity of drug-loaded NPs was evaluated in U-87 cells. The delivery and the subsequent cellular uptake of drug-loaded NPs could be enhanced by the presence of magnetic field and the usage of Tf as targeting ligand, respectively. In particular, cells treated with DOX-PTX-NPs-Tf with magnetic field showed the highest cytotoxicity as compared to those treated with DOX-PTX-NPs-Tf, DOX-PTX-NPs, DOX-PTX-NPs-Tf with free Tf. The in vivo therapeutic efficacy of drug-loaded NPs was evaluated in intracranial U-87 MG-luc2 xenograft of BALB/c nude mice. In particular, the DOX-PTX-NPs-Tf treatment exhibited the strongest anti-glioma activity as compared to the PTX-NPs-Tf, DOX-NPs-Tf or DOX-PTX-NPs treatment. Mice did not show acute toxicity after administrating with blank MNP-MSN-PLGA-Tf NPs. Overall, MNP-MSN-PLGA-Tf NPs are promising carriers for the delivery of dual drugs for effective treatment of brain glioma.     

Bioreducible heparin-based nanogel drug delivery system

Bioreducible heparin (HEP)-based nanogels were prepared by derivatizing HEP with vinyl group followed by copolymerizing with cystamine bisacrylamide in aqueous medium in the absence of surfactant. The hydrodynamic diameter of the HEP nanogels could be tuned in the range from 80 to 200 nm. Doxorubicin (DOX) was loaded into the HEP nanogels, and high drug loading content (30%) and efficiency (90%) were achieved. In vitro drug release test revealed that this drug delivery system exhibited strongly redox-sensitive drug release behavior that would greatly favor the in vivo drug delivery performance of the nanogels. After injected into tumor-bearing mice through tail vein, the DOX-loaded HEP nanogels showed remarkable accumulation in tumors as demonstrated by in vivo near infared fluorescence imaging and ex vivo DOX concentration measurements. The doxorubicin accumulation at tumor site goes beyond 9% injected dose per gram of tumor through such delivery system, making that DOX-loaded HEP nanogels have significantly superior in vivo antitumor activity.     

The cancer targeting potential of d-α-tocopheryl polyethylene glycol 1000 succinate tethered multi walled carbon nanotubes

Our main aim in the present investigation was to explore the in vitro and in vivo cancer targeting potential of the doxorubicin (DOX) laden d-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS) tethered surface engineered MWCNTs nanoformulation (DOX/TPGS-MWCNTs) and compare it with pristine MWCNTs and free doxorubicin solution. The developed MWCNTs nanoformulations were extensively characterized by Fourier-transform infrared, Raman spectroscopy, x-ray diffraction, electron microscopy, and in vitro and in vivo studies using MCF-7 cancer cell line. The entrapment efficiency was determined to be 97.2 ± 2.50% (DOX/TPGS-MWCNTs) and 92.5 ± 2.62% (DOX/MWCNTs) ascribed to π-π stacking interactions. The developed formulations depicted the sustained release pattern at the lysosomal pH (pH 5.3). The DOX/TPGS-MWCNTs showed enhanced cytotoxicity, cellular uptake and were most preferentially taken up by the cancerous cells via endocytosis mechanism. The DOX/TPGS-MWCNTs nanoconjugate depicted the significantly longer survival span (44 days, p < 0.001) than DOX/MWCNTs (23 days), free DOX (18 days) and control group (12 days). The obtained results also support the extended residence time and sustained release profile of the drug loaded surface engineered nanotubes formulations in body as compared to DOX solution. Overall we can conclude that the developed MWCNTs nanoconjugate have higher cancer targeting potential on tumor bearing Balb/c mice.     

Co-delivery of doxorubicin and paclitaxel by PEG-polypeptide nanovehicle for the treatment of non-small cell lung cancer

Despite progress, combination therapy of different functional drugs to increase the efficiency of anticancer treatment still remains challenges. An amphiphilic methoxy poly(ethylene glycol)-b-poly(l-glutamic acid)-b-poly(l-lysine) triblock copolymer decorated with deoxycholate (mPEsG-b-PLG-b-PLL/DOCA) was synthesized and developed as a nanovehicle for the co-delivery of anticancer drugs: doxorubicin (DOX) and paclitaxel (PTX). The amphiphilic copolymer spontaneously self-assembled into micellar-type nanoparticles in aqueous solutions and the blank nanoparticles possessed excellent stability. Three different domains of the copolymer performed distinct functions: PEG outer corona provided prolonged circulation, middle biodegradable and hydrophilic PLG shell was designed for DOX loading through electrostatic interactions, and hydrophobic deoxycholate modified PLL served as the container for PTX. In vitro cytotoxicity assays against A549 human lung adenocarcinoma cell line demonstrated that the DOX + PTX co-delivered nanoparticles (Co-NPs) exhibited synergistic effect in inducing cancer cell apoptosis. Ex vivo DOX fluorescence imaging revealed that Co-NPs had highly efficient targeting and accumulation at the implanted site of A549 xenograft tumor in vivo. Co-NPs exhibited significantly higher antitumor efficiency in reducing tumor size compared to free drug combination or single drug-loaded nanoparticles, while no obvious side effects were observed during the treatment, indicating this co-delivery system with different functional antitumor drugs provides the clinical potential in cancer therapy.     

Effects of mannose density on in vitro and in vivo cellular uptake and RNAi efficiency of polymeric nanoparticles

To evaluate the effects of mannose density on in vitro and in vivo cellular uptake and RNA interference (RNAi) efficiency of polymeric nanoparticles (NPs) in macrophages, mannose-modified trimethyl chitosan-cysteine (MTC) conjugates with mannose densities of 4%, 13%, and 21% (MTC-4, MTC-13, and MTC-21) were synthesized. Tumor necrosis factor-alpha (TNF-α) siRNA loaded MTC NPs with particle sizes of ∼150 nm exhibited desired structural stability and effectively protected siRNA from enzymatic degradation. Generally, cellular uptake and RNAi efficiency were affected by mannose density. As expected, MTC-21 NPs presented the maximum in vitro uptake and RNAi efficacy in Raw 264.7 cells among all NPs tested. However, MTC-4 NPs exhibited the optimal in vivo uptake by peritoneal exudate cell macrophages (PECs). In the inflammation model of acute hepatic injury, orally delivered MTC-4 and MTC-13 NPs worked better in silencing TNF-α expression and alleviating liver damage than MTC-21 NPs. As for the ulcerative colitis model, MTC-4 NPs outperformed MTC-13 and MTC-21 NPs with respect to TNF-α knockdown and therapeutic efficacy following oral administration. These results highlighted the importance of ligand density in cellular uptake and RNAi efficiency, which could serve as a guideline in the rational design of targeted nanocarriers for anti-inflammation therapy.     

Vascular toxicity of ultra-small TiO2 nanoparticles and single walled carbon nanotubes in vitro and in vivo

Ultra-small nanoparticles (USNPs) at 1–3 nm are a subset of nanoparticles (NPs) that exhibit intermediate physicochemical properties between molecular dispersions and larger NPs. Despite interest in their utilization in applications such as theranostics, limited data about their toxicity exist. Here the effect of TiO₂-USNPs on endothelial cells in vitro, and zebrafish embryos in vivo, was studied and compared to larger TiO₂-NPs (30 nm) and to single walled carbon nanotubes (SWCNTs). In vitro exposure showed that TiO₂-USNPs were neither cytotoxic, nor had oxidative ability, nevertheless were genotoxic. In vivo experiment in early developing zebrafish embryos in water at high concentrations of TiO₂-USNPs caused mortality possibly by acidifying the water and caused malformations in the form of pericardial edema when injected. Myo1C involved in glomerular development of zebrafish embryos was upregulated in embryos exposed to TiO₂-USNPs. They also exhibited anti-angiogenic effects both in vitro and in vivo plus decreased nitric oxide concentration. The larger TiO₂-NPs were genotoxic but not cytotoxic. SWCNTs were cytotoxic in vitro and had the highest oxidative ability. Neither of these NPs had significant effects in vivo. To our knowledge this is the first study evaluating the effects of TiO₂-USNPs on vascular toxicity in vitro and in vivo and this strategy could unravel USNPs potential applications.     

Multilayer nanoparticles for sustained delivery of exenatide to treat type 2 diabetes mellitus

A method for the sustained delivery of exenatide was proposed using nanoparticles (NPs) with a core/shell structure. The interactions between lipid bilayers and Pluronics were utilized to form various NPs using a layer-by-layer approach. Transmittance electron microscopy and dynamic light scattering were used to examine the morphology of the NPs. The in vitro release pattern was observed as a function of changes in the structure of the NPs, and the structural integrity of exenatide released was examined by SDS–PAGE analysis. Pharmacokinetics and antidiabetic effects were also observed with the structural change of NPs using in vivo animal models. In vitro–in vivo correlation was discussed in relation to manipulation of the NP structures.     

Hyaluronic acid-chitosan nanoparticles for co-delivery of MiR-34a and doxorubicin in therapy against triple negative breast cancer

Metastatic relapse, development of drug resistance in cancer cells and adverse side effects of chemotherapeutic agents are the major obstacles for effective chemotherapy against triple-negative breast cancer. To address these problems, miR-34a, a potent endogenous tumor suppressive molecule in breast cancer, was co-encapsulated with doxorubicin (DOX) into hyaluronic acid (HA)-chitosan (CS) nanoparticles (NPs) and simultaneously delivered into breast cancer cells for improved therapeutic effects of drug. DOX-miR-34a co-loaded HA-CS NPs were successfully prepared through ionotropic gelation method in water. In vitro and in vivo experiments showed that miR-34a and DOX can be efficiently encapsulated into HA-CS NPs and delivered into tumor cells or tumor tissues and enhance anti-tumor effects of DOX by suppressing the expression of non-pump resistance and anti-apoptosis proto-oncogene Bcl-2. In addition, intracellular restoration of miR-34a inhibited breast cancer cell migration via targeting Notch-1 signaling. The obtained data suggest that co-delivery of DOX and miR-34a could achieve synergistic effects on tumor suppression and nanosystem-based co-delivery of tumor suppressive miRNAs and chemotherapeutic agents may be a promising combined therapeutic strategy for enhanced anti-tumor therapy.     

Drug-loaded gold plasmonic nanoparticles for treatment of multidrug resistance in cancer

To investigate the possibility of treating multidrug-resistant tumors with targeted chemo-photothermal treatment, we conducted in vitro and in vivo studies using a doxorubicin (DOX)-resistant DLD-1 cell line (DLD-1/DOX) and nude mice with human xenograft tumors, respectively. The chemo-photothermal treatment consisted of DOX-loaded-poly(lactic-co-glycolic acid)–Au half-shell nanoparticles with targeting moieties of anti-death receptor-4 monoclonal antibody conjugated to the Au surface. The cells or xenografted tumors treated with nanoparticles were exposed to near infrared light for 10 min, which caused an increase in temperature to 45 °C. Chemo-photothermal treatment resulted in a large reduction in the rate of tumor xenograft growth on DLD-1/DOX tumor-bearing mice with a much smaller dose of DOX than conventional DOX chemotherapy. These results demonstrate that targeted chemo-photothermal treatment can provide high therapeutic efficacy and low toxicity in the treatment of multidrug-resistant tumors.     

Polyethylene glycol-conjugated hyaluronic acid-ceramide self-assembled nanoparticles for targeted delivery of doxorubicin

Polyethylene glycol (PEG)-conjugated hyaluronic acid-ceramide (HACE) was synthesized for the preparation of doxorubicin (DOX)-loaded HACE-PEG-based nanoparticles, 160 nm in mean diameter with a negative surface charge. Greater uptake of DOX from these HACE-PEG-based nanoparticles was observed in the CD44 receptor highly expressed SCC7 cell line, compared to results from the CD44-negative cell line, NIH3T3. A strong fluorescent signal was detected in the tumor region upon intravenous injection of cyanine 5.5-labeled nanoparticles into the SCC7 tumor xenograft mice; the extended circulation time of the HACE-PEG-based nanoparticle was also observed. Pharmacokinetic study in rats showed a 73.0% reduction of the in vivo clearance of DOX compared to the control group. The antitumor efficacy of the DOX-loaded HACE-PEG-based nanoparticles was also verified in a tumor xenograft mouse model. DOX was efficiently delivered to the tumor site by active targeting via HA and CD44 receptor interaction and by passive targeting due to its small mean diameter (<200 nm). Moreover, PEGylation resulted in prolonged nanoparticle circulation and reduced DOX clearance rate in an in vivo model. These results therefore indicate that PEGylated HACE nanoparticles represent a promising anticancer drug delivery system for cancer diagnosis and therapy.     

Doxorubicin-loaded NaYF4:Yb/Tm–TiO2 inorganic photosensitizers for NIR-triggered photodynamic therapy and enhanced chemotherapy in drug-resistant breast cancers

The combination therapy has exhibited important potential for the treatment of cancers, especially for drug-resistant cancers. In this report, bi-functional nanoprobes based on doxorubicin (DOX)-loaded NaYF₄:Yb/Tm–TiO₂ inorganic photosensitizers (FA-NPs-DOX) were synthesized for in vivo near infrared (NIR)-triggered inorganic photodynamic therapy (PDT) and enhanced chemotherapy to overcome the multidrug resistance (MDR) in breast cancers. Using the up-conversion luminescence (UCL) performance of NaYF₄:Yb/Tm converting near-infrared (NIR) into ultraviolent (UV) lights, reactive oxygen species (ROS) were triggered from TiO₂ inorganic photosensitizers for PDT under the irradiation of a 980 nm laser, by which the deep-penetration and low photo-damage could be reached. Moreover, nanocarrier delivery and folic acid (FA) targeting promoted the cellular uptake, and accelerated the release of DOX in drug-sensitive MCF-7 and resistant MCF-7/ADR cells. The toxicity assessment in vitro and in vivo revealed the good biocompatibility of the as-prepared FA-NPs-DOX nanocomposites. By the combination of enhanced chemotherapy and NIR-triggered inorganic PDT, the viability of MCF-7/ADR cells could decrease by 53.5%, and the inhibition rate of MCF-7/ADR tumors could increase up to 90.33%, compared with free DOX. Therefore, the MDR of breast cancers could be obviously overcome by enhanced chemotherapy and NIR-triggered inorganic PDT of FA-NPs-DOX nanocomposites under the excitation of a 980 nm laser.     

Combined mTOR inhibitor rapamycin and doxorubicin-loaded cyclic octapeptide modified liposomes for targeting integrin α3 in triple-negative breast cancer

A novel therapeutic strategy combining mTOR inhibitor rapamycin (RAPA) and doxorubicin (DOX)-loaded cyclic octapeptide liposomes for targeting integrin α3 was expected to combat the triple-negative breast cancer (TNBC). RAPA was loaded into PEG–PCL polymer micelles (M-RAPA) to realize solubilization. Flow cytometry analysis and laser confocal microscopy were used to evaluate the in vitro cellular uptake. The in vivo tumor targeting and bio-distribution were investigated by living fluorescence imaging. As the results, LXY modification significantly enhanced the cellular uptake of liposomal DOX in integrin α3 overexpressed TNBC cells (MDA-MB-231) in vitro and accordingly improved the tumor accumulation of liposomes in vivo. When used alone or in combination with LXY-LS-DOX, M-RAPA could greatly inhibit the expression of HIF-1α protein, which is always highly expressed in malignant cancers and involved in tumor angiogenesis, proliferation, therapeutic resistance and poor prognosis. Meanwhile, the improved efficacy of combined targeted therapy with LXY-LS-DOX and M-RAPA was demonstrated by the in vitro cytotoxicity against model TNBC cells and in vivo anti-tumor activity against mouse bearing TNBC model. These results suggested that the targeted combinational therapy based on LXY-LS-DOX and M-RAPA systems may provide a rational strategy to improve therapeutic outcomes of TNBC.     

Iron/iron oxide core/shell nanoparticles for magnetic targeting MRI and near-infrared photothermal therapy

The development of photothermal agents (PTAs) with good stability, low toxicity, highly targeting ability and photothermal conversion efficiency is an essential pre-requisite to near-infrared photothermal therapy (PTT) in vivo. Herein, we report the readily available PEGylated Fe@Fe₃O₄ NPs, which possess triple functional properties in one entity – targeting, PTT, and imaging. Compared to Au nanorods, they exhibit comparable photothermal conversion efficiency (∼20%), and much higher photothermal stability. They also show a high magnetization value and transverse relaxivity (∼156 mm⁻¹ s⁻¹), which should be applied for magnetic targeting MRI. With the Nd-Fe-B magnet (0.5 T) beside the tumour for 12 h on the xenograft HeLa tumour model, PEGylated Fe@Fe₃O₄ NPs exhibit an obvious accumulation. In tumour, the intensity of MRI signal is ∼ three folds and the increased temperature is ∼ two times than those without magnetic targeting, indicating the good magnetic targeting ability. Notably, the intrinsic high photothermal conversion efficiency and selective magnetic targeting effect of the NPs in tumour play synergistically in highly efficient ablation of cancer cells in vitro and in vivo.     

Core-Shell type lipid/rPAA-Chol polymer hybrid nanoparticles for in vivo siRNA delivery

Our previous study had reported that cholesterol-grafted poly(amidoamine) (rPAA-Chol polymer) was able to self-assemble into cationic nanoparticles and act as a potential carrier for siRNA transfection. In this study, the core–shell type lipid/rPAA-Chol hybrid nanoparticles (PEG-LP/siRNA NPs and T7-LP/siRNA NPs) were developed for improving in vivo siRNA delivery by modifying the surface of rPAA-Chol/siRNA nanoplex core with a lipid shell, followed by post-insertion of polyethylene glycol phospholipid (DSPE-PEG) and/or peptide (HAIYPRH, named as T7) modified DSPE-PEG-T7. The integrative hybrid nanostructures of LP/siRNA NPs were evidenced by dynamic light scattering (DLS), confocal laser scanning microscope (CLSM), cryo-transmission electron microscope (Cryo-TEM) and surface plasmon resonance (SPR) assay. It was demonstrated that the T7 peptide modified LP/siRNA NPs (T7-LP/siRNA NPs) exhibited uniform and spherical structures with particle size of 99.39 ± 0.65 nm and surface potential of 42.53 ± 1.03 mV, and showed high cellular uptake efficiency and rapid endosomal/lysosomal escape ability in MCF-7 cells. Importantly, in vitro gene silencing experiment demonstrated that both of pegylated and targeted LP/siEGFR NPs exhibited significantly stronger downregulation of EGFR protein expression level in MCF-7 cells, compared to that of the physical mixture of siRNA lipoplexes and rPAA-Chol/siRNA nanoplexes. In vivo tumor therapy on nude mice bearing MCF-7 tumors further confirmed that the targeted T7-LP/siEGFR NPs exhibited the greatest inhibition on tumor growth via transferrin receptor-mediated targeting delivery, without any activation of immune responses and significant body weight loss following systemic administration. These findings indicated that the core-shell type T7-LP/siRNA nanoparticles would be promising siRNA delivery systems for in vivo tumor-targeted therapy.     

Doxorubicin-loaded glycyrrhetinic acid-modified alginate nanoparticles for liver tumor chemotherapy

Doxorubicin (DOX)-loaded glycyrrhetinic acid (GA)-modified alginate (ALG) nanoparticles (DOX/GA-ALG NPs) were prepared for targeting therapy of liver cancer. This study focused on the biodistribution of DOX/GA-ALG NPs in Kunming mice as well as their antitumor activity against liver tumors in situ and side effects. The biodistribution data showed that the concentration of DOX in the liver reached 67.8 ± 4.9 μg/g after intravenous administration of DOX/GA-ALG NPs, which was 2.8-fold and 4.7-fold higher compared to non-GA-modified nanoparticles (DOX/CHO-ALG NPs) and DOX·HCl, respectively. The concentration of DOX in the heart of mice treated with DOX/GA-ALG NPs at any sampling time was relatively lower than that of mice treated with DOX·HCl. The liver tumor growth inhibition rate (IR) in situ was about 52.6% and the mortality was 33% in DOX·HCl group. In contrast, the IR was 76.6% and no mice died in the DOX/GA-ALG NPs group. Histological examination showed tumor necrosis in both experimental groups. Most importantly, the heart cells and the liver cells surrounding the tumor were not affected by administration of DOX/GA-ALG NPs, whereas myocardial necrosis and apparent liver cell swelling were observed after DOX·HCl administration.     

PLK1shRNA and doxorubicin co-loaded thermosensitive PLGA-PEG-PLGA hydrogels for osteosarcoma treatment

Combination cancer therapy has emerged as crucial approach for achieving superior anti-cancer efficacy. In this study, we developed a strategy by localized co-delivery of PLK1shRNA/polylysine-modified polyethylenimine (PEI-Lys) complexes and doxorubicin (DOX) using biodegradable, thermosensitive PLGA-PEG-PLGA hydrogels for treatment of osteosarcoma. When incubated with osteosarcoma Saos-2 and MG-63 cells, the hydrogel containing PLK1shRNA/PEI-Lys and DOX displayed significant synergistic effects in promoting the apoptosis of osteosarcoma cells in vitro. After subcutaneous injection of the hydrogel containing PLK1shRNA/PEI-Lys and DOX beside the tumors of nude mice bearing osteosarcoma Saos-2 xenografts, the hydrogels exhibited superior antitumor efficacy in vivo compared to the hydrogels loaded with PLK1shRNA/PEI-Lys or DOX alone. It is noteworthy that the combination treatment in vivo led to almost complete suppression of tumor growth up to 16 days, significantly enhanced PLK1 silencing, higher apoptosis of tumor masses, as well as increased cell cycle regulation. Additionally, ex vivo histological analysis of major organs of the mice indicated that the localized treatments showed no obvious damage to the organs, suggesting lower systemic toxicity of the treatments. Therefore, the strategy of localized, sustained co-delivery of PLK1shRNA and DOX by using the biodegradable, injectable hydrogel may have potential for efficient clinical treatment of osteosarcoma.     

Hyaluronic acid-modified hydrothermally synthesized iron oxide nanoparticles for targeted tumor MR imaging

We report a polyethyleneimine (PEI)-mediated approach to synthesizing hyaluronic acid (HA)-targeted magnetic iron oxide nanoparticles (Fe₃O₄ NPs) for in vivo targeted tumor magnetic resonance (MR) imaging applications. In this work, Fe₃O₄ NPs stabilized by PEI were first synthesized via a one-pot hydrothermal method. The formed PEI-stabilized Fe₃O₄ NPs were then modified with fluorescein isothiocyanate (FI) and HA with two different molecular weights to obtain two different Fe₃O₄ NPs (Fe₃O₄–PEI–FI–HA_6K and Fe₃O₄–PEI–FI–HA_31K NPs) with a size of 15–16 nm. The formed HA-modified multifunctional Fe₃O₄ NPs were characterized via different techniques. We show that the multifunctional Fe₃O₄ NPs are water-dispersible and colloidal stable in different aqueous media. In vitro cell viability and hemolysis studies reveal that the particles are quite cytocompatible and hemocompatible in the given concentration range. Furthermore, confocal microscopy and flow cytometry data demonstrate that HA-targeted Fe₃O₄ NPs are able to be uptaken specifically by cancer cells overexpressing CD44 receptors, and be used as efficient probes for targeted MR imaging of cancer cells in vitro and xenografted tumor models in vivo. With the tunable amine-based conjugation chemistry, the PEI-stabilized Fe₃O₄ NPs may be functionalized with other biological ligands or drugs for diagnosis and therapy of different biological systems.     

Encapsulating tantalum oxide into polypyrrole nanoparticles for X-ray CT/photoacoustic bimodal imaging-guided photothermal ablation of cancer

A nanotheranostic agent has been readily fabricated by encapsulating tantalum oxide (TaO_x) nanoparticles (NPs) into polypyrrole (PPy) NPs via a facile one-step chemical oxidation polymerization for bimodal imaging guided photothermal ablation of tumor. It was proved that the obtained composite nanoparticles (TaO_x@PPy NPs) with an average diameter around 45 nm could operate as an efficient bimodal contrast agent to simultaneously enhance X-ray CT and photoacoustic (PA) imaging greatly in vivo. Systemically administered TaO_x@PPy NPs could passively accumulate at the tumor site during the blood circulation, which was proved by both CT and PA imaging. In addition, the in vivo therapeutic examinations showed that TaO_x@PPy NPs exhibited significant photothermal cytotoxicity under near infrared laser irradiation. The tumor growth inhibition was evaluated to be 66.5% for intravenously injection and 100% for intratumoral injection, respectively. This versatile agent can be developed as a smart and promising nanoplatform that integrates multiple capabilities for both accurate diagnosing and precise locating of cancerous tissue, as well as effective photoablation of tumor.     

Oral delivery of shRNA and siRNA via multifunctional polymeric nanoparticles for synergistic cancer therapy

Galactose modified trimethyl chitosan-cysteine (GTC) conjugates with various galactose grafting densities were developed for oral delivery of Survivin shRNA-expression pDNA (iSur-pDNA) and vascular endothelial growth factor (VEGF) siRNA (siVEGF) in the synergistic and targeted treatment of hepatoma. iSur-pDNA and siVEGF loaded GTC nanoparticles (NPs) were prepared via electrostatic complexation and showed desirable stability in physiological fluids and improved intestinal permeation compared to naked genes. Galactose grafting density of GTC NPs significantly affected their in vitro and in vivo antitumor activities. GTC NPs with moderate galactose grafting density, termed GTC2 NPs, were superior in facilitating cellular uptake, promoting nuclear distribution, and silencing target genes, leading to notable inhibition of cell growth. In tumor-bearing mice, orally delivered GTC2 NPs could effectively accumulate in the tumor tissues and silence the expression of Survivin and VEGF, evoking increased apoptosis, inhibited angiogenesis, and thus the most efficient tumor regression. Moreover, compared with single gene delivery, co-delivery of iSur-pDNA and siVEGF showed synergistic effects on inhibiting in vitro cell proliferation and in vivo tumor growth. This study could serve as an effective approach for synergistic cancer therapy via oral gene delivery, and highlighted the importance of ligand grafting density in the rational design of targeted nanocarriers.