Van Du Nguyen

Preparation of HIFU-triggered tumor-targeted hyaluronic acid micelles for controlled drug release and enhanced cellular uptake

In this study, a novel type of high intensity focused ultrasound (HIFU)-triggered active tumor-targeting polymeric micelle was prepared and investigated for controlled drug release and enhanced cellular uptake. Amphiphilic hyaluronic acid (HA) conjugates were synthesized to form docetaxel loaded micelles in aqueous conditions with high encapsulation efficiencies of over 80%. The micelle sizes were limited to less than 150nm, and they varied slightly according to the encapsulated drug amount. Modifying the micellar surface modification with polyethylene glycol diamine successfully inhibited premature drug leakage at a certain level, and it can be expected to prolong the circulation time of the particles in blood. In addition, high-intensity focused ultrasound was introduced to control the release of docetaxel from micelles, to which the release behavior of a drug can be tuned. The in-vitro cell cytotoxicity of docetaxel-loaded micelles was verified against CT-26 and MDA-MB-231 cells. The IC50 values of drug-loaded micelles to CT-26 and MDA-MB-231 cells were 1230.2 and 870.9ng/mL, respectively. However, when exposed to HIFU, the values decreased significantly, to 181.9 and 114.3ng/mL, suggesting that HIFU can enhance cell cytotoxicity by triggering the release of a drug from the micelles. Furthermore, cellular uptake tests were conducted via the quantitative analysis of intracellular drug concentration within CT-26 (CD44 negative), MDA-MB-231 (CD44 positive), and MDA-MB-231 (CD44 blocked), and then imaged with coumarin-6 loaded micelles. The results verified that intracellular drug delivery can be enhanced efficiently via the CD44 receptor-mediated endocytosis of HA micelles. Moreover, HIFU enhanced the cellular uptake behavior by altering the permeability of the cell membrane. It was also able to aid with the extravasation of micelles into the interior of tumors, which will be explained in further research. Therefore, the present study demonstrates that the micelles prepared in this study can emerge as promising nanocarriers of chemotherapeutic agents for controlled drug release and tumor targeting in cancer treatment.

Preparation of Engineered Salmonella Typhimurium-Driven Hyaluronic-Acid-Based Microbeads with Both Chemotactic and Biological Targeting Towards Breast Cancer Cells for Enhanced Anticancer Therapy.

In this study, a new type of targeted bacteriobots is prepared and investigated as a therapeutic strategy against solid tumors. Maleimide-functionalized hyaluronic acid (HA) polymer is synthesized and cross-linked with four-arm-thiolated polyethylene glycol (PEG-SH) to form HA microbeads with diameter of 8 μm through the Michael-type addition. Docetaxel (DTX)-loaded nanoparticles are encapsulated in HA-PEG microbeads and sustained in vitro drug-release pattern of the DTX from the HA-PEG microbeads is observed for up to 96 h. Dual-targeted bacteriobots are prepared using CD 44 receptor-targeted HA microbeads synthesized via microfluidics, followed by the attachment of the flagellar bacterium Salmonella typhimurium, which have been genetically engineered for tumor targeting, onto the surface of the HA microbeads by the specific interaction between streptavidin on the HA beads and biotin on the bacteria. After the attachment of bacteria, the bacteriobots show an average velocity of 0.72 μm s(-1) and high chemotactic migration velocity of 0.43 μm s(-1) towards 4T1 cells lysates. CD 44 receptor-specific cellular uptake is verified through flow cytometry analysis and confocal imaging, demonstrating enhanced intracellular uptake in CD 44 receptor positive tumor cells compared to normal cells. Therefore, the present study suggests that these bacteriobots have dual-tumor-targeting abilities displaying their potential for targeted anticancer therapy.

Hybrid-Actuating Macrophage-Based Microrobots for Active Cancer Therapy

Using macrophage recruitment in tumors, we develop active, transportable, cancer theragnostic macrophage-based microrobots as vector to deliver therapeutic agents to tumor regions. The macrophage-based microrobots contain docetaxel (DTX)-loaded poly-lactic-co-glycolic-acid (PLGA) nanoparticles (NPs) for chemotherapy and Fe3O4 magnetic NPs (MNPs) for active targeting using an electromagnetic actuation (EMA) system. And, the macrophage-based microrobots are synthesized through the phagocytosis of the drug NPs and MNPs in the macrophages. The anticancer effects of the microrobots on tumor cell lines (CT-26 and 4T1) are evaluated in vitro by cytotoxic assay. In addition, the active tumor targeting by the EMA system and macrophage recruitment, and the chemotherapeutic effect of the microrobots are evaluated using three-dimensional (3D) tumor spheroids. The microrobots exhibited clear cytotoxicity toward tumor cells, with a low survivability rate (<50%). The 3D tumor spheroid assay showed that the microrobots demonstrated hybrid actuation through active tumor targeting by the EMA system and infiltration into the tumor spheroid by macrophage recruitment, resulting in tumor cell death caused by the delivered antitumor drug. Thus, the active, transportable, macrophage-based theragnostic microrobots can be considered to be biocompatible vectors for cancer therapy.

Nanohybrid magnetic liposome functionalized with hyaluronic acid for enhanced cellular uptake and near-infrared-triggered drug release

The aim of this work is to prepare and evaluate a novel lipid-polymer hybrid liposomal nanoplatform (hyaluronic acid-magnetic nanoparticle-liposomes, HA-MNP-LPs) as a vehicle for targeted delivery and triggered release of an anticancer drug (docetaxel, DTX) in human breast cancer cells. We first synthesize an amphiphilic hyaluronic acid hexadecylamine polymer (HA-C16) to enhance the targeting ability of the hybrid liposome. Next, HA-MNP-LPs are constructed to achieve an average size of 189.93±2.74nm in diameter. In addition, citric acid-coated magnetic nanoparticles (MNPs) are prepared and embedded in the aqueous cores while DTX is encapsulated in the hydrophobic bilayers of the liposomes. Experiments with coumarin 6 loaded hybrid liposomes (C6/HA-MNP-LPs) show that the hybrid liposomes have superior cellular uptake in comparison with the conventional non-targeting liposomes (C6/MNP-LPs), and the result is further confirmed by Prussian blue staining. Under near-infrared laser irradiation (NIR, 808nm), the HA-MNP-LPs aqueous solution can reach 46.7°C in 10min, and the hybrid liposomes released over 20% more drug than the non-irradiated liposomes. Using a combination of photothermal irradiation and chemotherapy, the DTX-loaded hybrid liposomes (DTX/HA-MNP-LPs) significantly enhance therapeutic efficacy, with the IC50 value of 0.69±0.10μg/mL, which is much lower than the values for DTX monotherapy. Consequently, the prepared hybrid nanoplatform may offer a promising drug delivery vehicle with selective targeting and enhanced drug release in treating CD44-overexpressing cancers.

Folate-receptor-targeted NIR-sensitive polydopamine nanoparticles for chemo-photothermal cancer therapy

We propose the use of folate-receptor-targeted, near-infrared-sensitive polydopamine nanoparticles (NPs) for chemo-photothermal cancer therapy as an enhanced type of drug-delivery system which can be synthesized by in situ polymerization and conjugation with folic acid. The NPs consist of a Fe3O4/Au core, coated polydopamine, conjugated folic acid, and loaded anti-cancer drug (doxorubicin). The proposed multifunctional NPs show many advantages for therapeutic applications such as good biocompatibility and easy bioconjugation. The polydopamine coating of the NPs show a higher photothermal effect and thus more effective cancer killing compared to Fe3O4/Au nanoparticles at the same intensity as near-infrared laser irradiation. In addition, the conjugation of folic acid was shown to enhance cancer cellular uptake efficiency via the folate receptor and thus improve chemotherapeutic efficiency. Through in vitro cancer cell treatment testing, the proposed multifunctional NPs showed advanced photothermal and chemotherapeutic performance. Based on these enhanced anti-cancer properties, we expect that the proposed multifunctional NPs can be used as a drug-delivery system in cancer therapy.

Combined photothermal-chemotherapy of breast cancer by near infrared light responsive hyaluronic acid-decorated nanostructured lipid carriers

In this study, a novel type of hyaluronic acid (HA)-decorated nanostructured lipid carrier (NLC) was prepared and investigated as a light-triggered drug release and combined photothermal-chemotherapy for cancer treatment. Polyhedral gold nanoparticles (Au NPs) with an average size of 10 nm were synthesized and co-encapsulated with doxorubicin (DOX) in the matrix of NLCs with a high drug loading efficiency (above 80%). HA decoration was achieved by the electrostatic interaction between HA and CTAB on the NLC surface. A remarkable temperature increase was observed by exposing the Au NP-loaded NLCs to an NIR laser, which heated the samples sufficiently (above 40 °C) to kill tumor cells. The entrapped DOX exhibited a sustained, stepwise NIR laser-triggered drug release pattern. The biocompatibility of the NLCs was investigated by MTT assay and the cell viability was maintained above 85%, even at high concentrations. The intracellular uptake of free DOX and entrapped DOX, observed by confocal microscopy, revealed two distinct uptake mechanisms, i.e. passive diffusion and endocytosis, respectively. In particular, internalization of the HA-Au-DOX-NLCs was more extensively enhanced than the Au-DOX-NLCs, which was attributed to HA-CD44 receptor-mediated endocytosis. Meanwhile, the internalized NLCs successfully escaped from the lysosomes, increasing the intracellular DOX. The HA-Au-DOX-NLCs IC50 value decreased from 2.3 to 0.6 μg ml-1 with NIR irradiation at 72 h, indicating the excellent synergistic antitumor effect of photothermal-chemotherapy. The photothermal ablation was further confirmed by a live/dead cell staining assay. Thus, a combined photothermal-chemotherapy approach has been proposed as a promising strategy for cancer treatment.

Manipulation of tumor targeting cell-based microrobots carrying NIR light sensitive therapeutics using EMA system and chemotaxis

In this study, we prepare and evaluate a novel cellbased micro-platform (microrobot) for active tumor therapy. The microrobots are fabricated utilizing the engulfment activity of immune cells (macrophages) with drug-loaded magnetic liposomes via phagocytosis. First, we synthesize magnetic nanoparticles (MNP) with superparamagnetic properties and high energy absorbance to near-infrared (NIR) light, and load the MNPs to liposomes (MNP-DLs). Then, we prepare the microrobots by incubating the MNP-DLs with the macrophages. After that, we characterize the tumor targeting ability of the microrobots using electromagnetic actuating (EMA) system and a transwell chemotactic assay. Experiment results show that the microrobots can be controlled by an external magnetic field to reach the average velocity of approximately 11 μm/second, and they can cross the membranes mimicking the blood barrier to tumor chemo-attractants with the infiltration rate up to 74%. Therefore, the study proposes an innovative approach for active tumor targeting and NIR light triggered drug delivery using the developed cellular microrobots.

Novel active locomotive capsule endoscope with micro-hydraulic pump for drug delivery function

This paper presents a novel mechanism and design of capsule endoscope in order to perform an active locomotive capsule endoscope (ALICE) robot integrated with micro-hydraulic pump for drug delivery function. The proposed locomotive capsule endoscope can actively move and investigate in gastrointestinal tract, powered externally by an electro-magnetic actuation (EMA) system. To perform a drug pumping function, the rotating frequency of the active hydraulic pump can be adjusted by the EMA system. The novel capsule endoscope with the micro-hydraulic pump is focused on target drug delivery function. The capsule endoscope is able to target suspicious region and release controllable amount of drug. Through preliminary tests of the locomotive capsule endoscope with the micro-pump, the feasibility of the locomotion and the drug releasing of the novel capsule endoscope will be presented. The micro-hydraulic pump for a drug delivery function will be a potential component for a future capsule endoscope with active maneuverability, diagnostic and therapeutic functions.

Motility steering of bacteriobots using chemical gradient microchannel

In the recent years, several groups focused on the development of bacteria based microrobots (bacteriobots) using microbeads and flagellar bacteria. The bacteriobots will be a promising cancer therapeutic method in the future with drug encapsulation inside microbeads. However, it remains elusive that how to steer the motion of bacteriobots. In this study, we attempted to steer the motion of bacteriobots with the intrinsic bacterial chemotaxis to particular chemicals. Therefore, a new microfluidic channel was designed and fabricated through micro-molding method of hydrogel patterns, which a sustained chemical gradient was investigated using rhodamine B at various determined time intervals. Thereafter, the bacteriobots solution was injected into the central channel with chemoattractant gradient, then the chemotactic motion of bacteriobots was investigated through a microscope and analyzed with MATLAB program. Moreover, some other chemoattractant chemicals, secreted from tumor cells could also stimulate the tumor targeting ability possible with bacteriobots. Overall, the motion of bacteriobots can be steered through bacterial chemotaxis, and we expect drug embedded bacteriobots to be a new targeted therapy in cancer treatment.

Effect of Chitosan on Motility of Bacteria-Driven Liposomal Microrobots

This study proposes a prototype of bacteria-based microrobots using chitosan-coated liposomes attached to a Salmonella enteritidis bacterial strain. The attachment of the liposome and the bacteria is performed by interaction between the positive charge surface of the liposomes and the gram-negative bacteria. The liposomes are fabricated using hydration method to obtain the average diameter of 10 um and they are coated with chitosan. The chitosan coating is shown to have effect on motility of the microrobots. First, the bacteria cannot attach to chitosan-uncoated liposomes, but they can easily adhere to the chitosan-coated liposomes. Second, when the concentration of chitosan increases from 0.1% to 0.5%, average velocity of the microrobots increases from 1.20±0.12 um/s to 3.25±0.35 um/s. However, when chitosan concentration increases to 1% the average velocity of the microrobots slightly decreases from 3.25±0.35 um/s to 3.17±0.33 um/s, respectively. The study suggests that using chitosan coating can be a potential method for further development of therapeutic bacteria-based liposomal microrobots.