Chengbin Yang

A Light-Driven Therapy of Pancreatic Adenocarcinoma Using Gold Nanorods-Based Nanocarriers for Co-Delivery of Doxorubicin and siRNA.

In this work, we report the engineering of polyelectrolyte polymers coated Gold nanorods (AuNRs)-based nanocarriers that are capable of co-delivering small interfering RNA (siRNA) and an anticancer drug doxorubicin (DOX) to Panc-1 cancer cells for combination of both chemo- and siRNA-mediated mutant K-Ras gene silencing therapy. Superior anticancer efficacy was observed through synergistic combination of promoted siRNA and DOX release upon irradiating the nanoplex formulation with 665 nm light. Our antitumor study shows that the synergistic effect of AuNRs nanoplex formulation with 665 nm light treatment is able to inhibit the in vivo tumor volume growth rate by 90%. The antitumor effect is contributed from the inactivation of K-Ras gene and thereby causing a profound synthesis (S) phase arrest in treated Panc-1 cells. Our study shows that the percentage of Panc-1 cells treated by nanoplex formulation with S phase is determined to be 35% and it is 17% much higher than that of Panc-1 cells without any treatments. The developed nanotherapy formulation here, that combines chemotherapy, RNA silencing and NIR window light-mediated therapy, will be seen to be the next natural step to be taken in the clinical research for improving the therapeutic outcomes of the pancreatic adenocarcinoma treatment.

Aggregation-induced emission (AIE) dye loaded polymer nanoparticles for gene silencing in pancreatic cancer and their in vitro and in vivo biocompatibility evaluation

We have developed aggregation-induced emission (AIE) dye loaded polymer nanoparticles with deep-red emission for siRNA delivery to pancreatic cancer cells. Two US Food and Drug Administration (FDA) approved surfactant polymers, Pluronics F127 and PEGylated phospholipid, were used to prepare the dye-loaded nanoparticle formulations and they can be used as nanovectors for gene silencing of mutant K-ras in pancreatic cancer cells. The successful transfection of siRNA by the developed nanovectors was confirmed by the fluorescent imaging and quantified through flow cytometry. Quantitative real time polymerase chain reaction (PCR) indicates that the expression of the mutant K-ras oncogene from the MiaPaCa-2 pancreatic cancer cells has been successfully suppressed. More importantly, our in vivo toxicity study has revealed that both the nanoparticle formulations are highly biocompatible in BALC/c mice. Overall, our results suggest that the AIE dye-loaded polymer nanoparticle formulations developed here are suitable for gene delivery and have high potential applications in translational medicine research.

Synthesis and Characterization of Mn:ZnSe/ZnS/ZnMnS Sandwiched QDs for Multimodal Imaging and Theranostic Applications

In this work, a facile aqueous synthesis method is optimized to produce Mn:ZnSe/ZnS/ZnMnS sandwiched quantum dots (SQDs). In this core-shell co-doped system, paramagnetic Mn(2+) ions are introduced as core and shell dopants to generate Mn phosphorescence and enhance the magnetic resonance imaging signal, respectively. T1 relaxivity of the nanoparticles can be improved and manipulated by raising the shell doping level. Steady state and time-resolved optical measurements suggest that, after high level shell doping, Mn phosphorescence of the core can be sustained by the sandwiched ZnS shell. Because the SQDs are free of toxic heavy metal compositions, excellent biocompatibility of the prepared nanocrystals is verified by in vitro MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. To explore the theranostic applications of SQDs, liposome-SQD assemblies are prepared and used for ex vivo optical and magnetic resonance imaging. In addition, these engineered SQDs as nanocarrier for gene delivery in therapy of Panc-1 cancer cells are employed. The therapeutic effects of the nanocrystals formulation are confirmed by gene expression analysis and cell viability assay.

Revisiting the principles of preparing aqueous quantum dots for biological applications: the effects of surface ligands on the physicochemical properties of quantum dots

Surface functionalization of quantum dots (QDs) is one of the most important aspects for the design and preparation of the desired QDs for specific biomedical applications. The surface ligands not only render the QDs water-dispersible, but also endow them with different functional groups for bioconjugation. More importantly, as the surface ligand layer on the QD surface is responsible for interacting with the biological environments, the type of surface ligand will greatly affect the response from the cells, such as the cellular uptake and cytotoxicity. In this paper, we investigate the effects of the surface ligand on the physicochemical properties of QDs and examine different QD formulations for possible biomedical applications. Seven types of QD formulations were prepared by anchoring the CdSe/CdS/ZnS QDs surface with either short-chain mercapto ligands (MPA, MSA, cysteine, AET) or PEG derivative ligands (mPEG-SH, CM-PEG-SH, NH2-PEG-SH). We then conducted a systematic study to evaluate the colloidal stability, photostability, cellular uptake and in vitro toxicity of the formulations. The colloidal stability was evaluated by the particle size change in water, acidic/neutral/alkaline buffer solutions and cell culture medium. Our results show that the carboxyl-terminated QDs have the best colloidal stability in water and alkaline solutions. PEG-capped QDs are more stable than short-chain ligand modified QDs in cell culture medium. For the photostability of different QD formulations under UV irradiation, we observed that the MPA-, MSA- and Cys-QDs had better photostability than that of the PEG modified QDs, whereas the AET-QD is the least stable one. Cellular uptake of QDs was evaluated using cell imaging and quantified by flow cytometry. The PEG chains and surface charge of QDs were found to play critical roles in the cellular uptake. Using RAW246.7 macrophage cells as the cellular uptake model, we discovered that the anionic QDs had a much higher uptake compared to the cationic QD formulations. In general, each set of prepared QD formulation with a specific type of surface ligand display certain strengths and limitations in different aspects of their physicochemical properties. Therefore, one should carefully consider and choose the type of QD formulation in the experiments thereby minimizing its impacts arising from their limitations.

Biodegradable nanoparticle-mediated K-ras down regulation for pancreatic cancer gene therapy

RNA interference (RNAi) targeting the K-ras oncogene mutation in pancreatic cancer mediated by small interfering RNA (siRNA) transfection is a very promising treatment. However, the rapid degradation and negative charge of naked siRNAs restrict their direct delivery into cells. In this contribution, we propose a safe and effective transmembrane transport nanocarrier formulation based on a newly developed biodegradable charged polyester-based vector (BCPV) for K-ras siRNA delivery into pancreatic cancer cells. Our results have shown that these biodegradable and biocompatible vectors are able to transfect siRNAs targeting mutant K-ras into MiaPaCa-2 cells with high transfection and knockdown efficiency. More importantly, the RNAi process initiated a cascade gene regulation of the downstream proteins of K-ras associated with cell proliferation, migration, invasion and apoptosis. We observed that after the mutant K-ras siRNA transfection, the growth, migration and invasion of the MiaPaCa-2 cells were significantly reduced; also, the apoptosis of the pancreatic cancer cells was promoted. Although in vivo testing data are limited, we propose that the BCPV based nanoparticle formulation could be a promising candidate as non-viral vectors for gene therapy in clinical settings.

Folic acid-conjugated organically modified silica nanoparticles for enhanced targeted delivery in cancer cells and tumor in vivo

In this work, we report the synthesis of dye-loaded and folic acid (FA)-conjugated organically modified silica (ORMOSIL) nanoparticles as targeted optical nanoprobes for in vitro and in vivo imaging. The dye-loaded ORMOSIL (ORMD) nanoparticles are synthesized by a facile aqueous phase (oil-in-water microemulsion) approach and they have an average size of 30 nm. We observed that the functionalization of FA onto the particle surface led to a strong cellular uptake of FA-conjugated ORMD nanoparticles for pancreatic cancer Miapaca-2 cells and hepatoma SMMC7721 cells with FA receptor overexpression. Such a trend is not observed for 293T cells and breast cancer MCF7 cells as these cells possess low-expression of the FA receptor. The in vivo imaging studies demonstrate that FA-ORMD nanoparticles are preferentially accumulated in tumor sites. Histological studies reveal that no-ill effects are observed in the major organs of treated mice when compared to the untreated ones. Because of the facile synthesis process, high specificity for tumor targeting and low toxicity of FA-ORMD nanoparticles, significant potential for early-cancer detection application is expected.

Pancreatic cancer gene therapy using an siRNA-functionalized single walled carbon nanotubes (SWNTs) nanoplex

The discovery of RNA interference (RNAi) has created a new platform for cancer therapy applications. This approach utilizes small interfering RNA (siRNA) molecules to regulate the expression of a specific target gene and subsequently suppresses the growth of the cancer cells. However, the formulation of free siRNAs alone is incapable of transfecting cells as they are negatively charged and degrade in biological fluids. For successful siRNA transfection, a biocompatible and functional carrier is needed. In this contribution, we demonstrated the preparation of functionalized single walled carbon nanotubes (SWNTs) as efficient siRNA carriers and utilized the SWNTs/siRNA nanoplex for the in vitro gene therapy of pancreatic cancer. Through fluorescent imaging and quantitative flow cytometric analysis, we observed a high siRNA transfection efficiency mediated by the nanoplex formulation. We demonstrated the successful internalization of the nanoplex by the pancreatic cancer cell and the subsequent release of the siRNAs from the nanoplex, which resulted in a down-regulation of the target gene. In addition, the functionalized SWNTs proved to be highly biocompatible as assessed by cell viability tests. Our results suggest that in the near future the SWNTs may be able to serve as a multifunctional nanoplatform for the in vivo targeted gene therapy of pancreatic cancer.

Synthesis and characterization of multifunctional hybrid-polymeric nanoparticles for drug delivery and multimodal imaging of cancer.

In this study, multifunctional hybrid-polymeric nanoparticles were prepared for the treatment of cultured multicellular tumor spheroids (MCTS) of the PANC-1 and MIA PaCa-2 pancreatic carcinoma cell lines. To synthesize the hybrid-polymeric nanoparticles, the poly lactic-co-glycolic acid core of the particles was loaded with Rhodamine 6G dye and the chemotherapeutic agent, Paclitaxel, was incorporated into the outer phospholipid layer. The surface of the nanoparticles was coated with gadolinium chelates for magnetic resonance imaging applications. This engineered nanoparticle formulation was found to be suitable for use in guided imaging therapy. Specifically, we investigated the size-dependent therapeutic response and the uptake of nanoparticles that were 65 nm, 85 nm, and 110 nm in size in the MCTS of the two pancreatic cancer cell lines used. After 24 hours of treatment, the MCTS of both PANC-1 and MIA PaCa-2 cell lines showed an average increase in the uptake of 18.4% for both 65 nm and 85 nm nanoparticles and 24.8% for 110 nm nanoparticles. Furthermore, the studies on therapeutic effects showed that particle size had a slight influence on the overall effectiveness of the formulation. In the MCTS of the MIA PaCa-2 cell line, 65 nm nanoparticles were found to produce the greatest therapeutic effect, whereas 12.8% of cells were apoptotic of which 11.4% of cells were apoptotic for 85 nm nanoparticles and 9.79% for 110 nm nanoparticles. Finally, the study conducted in vivo revealed the importance of nanoparticle size selection for the effective delivery of drug formulations to the tumors. In agreement with our in vitro results, excellent uptake and retention were found in the tumors of MIA PaCa-2 tumor-bearing mice treated with 110 nm nanoparticles.

Biodegradable nanocarriers for small interfering ribonucleic acid (siRNA) co-delivery strategy increase the chemosensitivity of pancreatic cancer cells to gemcitabine

Ribonucleic acid (RNA) interference (RNAi) therapies are promising cancer treatment modalities that can specifically target abnormal proto-oncogenes, thus improving the therapeutic effect. For the treatment of pancreatic cancer, targeting one mutant proto-oncogene by RNAi usually does not yield the desired therapeutic efficiency. Both K-ras gene mutations and Notch1 overexpression are common symptoms in pancreatic cancer patients, and play a crucial role in pancreatic cancer cell drug resistance. In this study, biodegradable charged polyester-based vectors (BCPVs) were synthesized for the co-delivery of K-ras and Notch1 small interfering ribonucleic acid (siRNA) into MiaPaCa-2 cells (pancreatic cancer cell line) to overcome drug resistance to gemcitabine (GEM), a first-line chemotherapeutic drug used in the clinic. BCPVs could effectively absorb negative siRNA to form a capsule-like structure, prevent siRNA from nuclease digestion in the serum, and promote effective siRNA cell internalization and endosomal escape. Through K-ras and Notch1 gene silencing in MiaPaCa-2 cells, BCPV-siRNAK-ras-siRNANotch1 nanocomplexes effectively reversed the epithelia-mesenchymal transition (EMT) in MiaPaCa-2 cells, thereby greatly enhancing the sensitivity of MiaPaCa-2 cells to GEM. MiaPaCa-2 cell proliferation, migration, and invasion were effectively inhibited, and cell apoptosis was also significantly enhanced by the synergistic antitumor effect of BCPV-siRNAK-ras-siRNANotch1 nanocomplexes and GEM. These results suggest that this combination RNAi therapy can be used to improve cancer cell sensitivity to chemotherapeutic drugs. Specifically, this newly developed strategy has a great potential for treating pancreatic cancer.

Millifluidic synthesis of cadmium sulfide nanoparticles and their application in bioimaging

In this paper, a miniature fluidic synthesis platform utilizing millimeter dimension channels for the synthesis of cadmium sulfide (CdS) quantum dots and nanocrystals is demonstrated. Traditional nanoparticle synthesis techniques involve macroscopic flasks where reaction conditions may vary at different positions inside the vessel. Therefore challenges in terms of batch reproducibility for large scale production are of great concern. Here, we show that it is possible to replicate reaction conditions so as to produce nanoparticles with similar optical characteristics across different batches using the same reaction parameters. Particle size control was established by varying the flow rate of the precursors, yielding gradually increasing nanocrystal sizes from 2.4 nm to 3.7 nm with increasing residence time. The as-synthesized CdS nanoparticles exhibited tunable photoluminescence by adjusting the molar ratio of the cadmium and sulfur precursors, giving rise to greenish-blue and orange-red emissions under ultraviolet light illumination. The particles were then studied and characterized using transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) absorbance, photoluminescence, X-ray diffraction (XRD) and selected area electron diffraction (SAED) techniques. Lastly, bioimaging of RAW264.7 mice macrophage cells using ligand exchanged CdS nanoparticles is presented.