Guimiao Lin

Functionalized Quantum Dots for Biosensing and Bioimaging and Concerns on Toxicity

Considerable efforts have been devoted to the development of novel functionalized nanomaterials for bio-oriented applications. With unique optical properties and molar scale production, colloidal photoluminescent quantum dots (QDs) have been properly functionalized with controlled interfaces as new class of optical probes with extensive use in biomedical research. In this review, we present a brief summary on the current research interests of using fine engineered QDs as a nanoplatform for biomedical sensing and imaging applications. In addition, recent concerns on the potential toxic effects of QDs are described as a general guidance for the development on QD formulations in future studies.

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.

PEGylated Phospholipid Micelle-Encapsulated Near-Infrared PbS Quantum Dots for in vitro and in vivo Bioimaging

Surface modification and functionalization of bioconjugated quantum dots (QDs) has drawn great attention for the past few years due to their wide applications in biomedical research. In this contribution, we demonstrate the use of PEGylated phospholipid micelles to encapsulate near infrared emitting ultra-small lead sulfide (PbS) QDs for in vitro and in vivo imaging. The cytotoxicity of the micelle-encapsulated QDs formulation was evaluated using MTS assay and histological analysis studies. We have found that upon encapsulating the QDs with phospholipid micelle, the toxicity of the PbS QDs is reduced, from which we envision that the PEGylated phospholipid micelle-encapsulated PbS QDs formulation can be used as theranostics probes for some selected applications in cell imaging and small animals study.

In vivo toxicity assessment of non-cadmium quantum dots in BALB/c mice

UNLABELLED Along with widespread usage of QDs in electronic and biomedical industries, the likelihood of QDs exposure to the environment and humans is deemed to occur when the QD products are degraded or handled as waste for processing. To date, there are very few toxicological reports available in the literature for non-cadmium QDs in animal models. In this work, we studied the long term in vivo toxicity of InP/ZnS QDs in BALB/c mice. The biodistribution, body weight, hematology, blood biochemistry, and organ histology were determined at a very high dosage (25 mg/kg) of InP/ZnS QDs over 84 days period. Our results manifested that the QDs formulation did not result in observable toxicity in vivo within the evaluation period, thereby suggesting that the InP/ZnS QDs can be utilized as optical probes or nanocarrier for selected in vivo biological applications when an optimized dosage is employed. FROM THE CLINICAL EDITOR This study investigated the toxicity of quantum dots in BALB/c mice, and concluded that no organotoxicity was detectable despite of using high concentration of InP/ZnS quantum dots with prolonged exposure of 3 months.

Synthesis of Luminescent Near-Infrared AgInS2 Nanocrystals as Optical Probes for In Vivo Applications

Near infrared quantum dots have been receiving great attention as fluorescent optical probes for in vivo imaging applications. In this contribution, we report the synthesis and surface functionalization of cadmium free ternary AgInS2 nanocrystals emitting in the near infrared range for successful in vitro and in vivo bioimaging applications. The FDA approved triblock copolymer Pluronic F127 was used to encapsulate the nanocrystals and made them dispersible in aqueous solution. By employing a whole body small animal optical imaging setup, we were able to use the AgInS2 nanocrystals formulation for passive targeted delivery to the tumor site. The ultra-small crystal size, near-infrared emitting luminescence, and high quantum yield make the AgInS2 nanocrystals an attractive candidate as a biological contrast agent for cancer sensing and imaging.

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.

Biodegradable Nanocapsules as siRNA Carriers for Mutant K‐Ras Gene Silencing of Human Pancreatic Carcinoma Cells

The application of small interfering RNA (siRNA)-based RNA interference (RNAi) for cancer gene therapy has attracted great attention. Gene therapy is a promising strategy for cancer treatment because it is relatively non-invasive and has a higher therapeutic specificity than chemotherapy. However, without the use of safe and efficient carriers, siRNAs cannot effectively penetrate the cell membranes and RNAi is impeded. In this work, cationic poly(lactic acid) (CPLA)-based degradable nanocapsules (NCs) are utilized as novel carriers of siRNA for effective gene silencing of pancreatic cancer cells. These CPLA-NCs can readily form nanoplexes with K-Ras siRNA and over 90% transfection efficiency is achieved using the nanoplexes. Cell viability studies show that the nanoparticles are highly biocompatible and non-toxic, indicating that CPLA-NC is a promising potential candidate for gene therapy in a clinical setting.

An Electrochemically Actuated MEMS Device for Individualized Drug Delivery: an In Vitro Study

Individualized disease treatment is a promising branch for future medicine. In this work, we introduce an implantable microelectromechanical system (MEMS) based drug delivery device for programmable drug delivery. An in vitro study on cancer cell treatment has been conducted to demonstrate a proof-of-concept that the engineered device is suitable for individualized disease treatment. This is the first study to demonstrate that MEMS drug delivery devices can influence the outcome of cancer drug treatment through the use of individualized disease treatment regimes, where the strategy for drug dosages is tailored according to different individuals. The presented device is electrochemically actuated through a diaphragm membrane and made of polydimethylsiloxane (PDMS) for biocompatibility using simple and cost-effective microfabrication techniques. Individualized disease treatment was investigated using the in vitro programmed delivery of a chemotherapy drug, doxorubicin, to pancreatic cancer cell cultures. Cultured cell colonies of two pancreatic cancer cell lines (Panc-1 and MiaPaCa-2) were treated with three programmed schedules and monitored for 7 days. The result shows that the colony growth has been successfully inhibited for both cell lines among all the three treatment schedules. Also, the different observations between the two cell lines under different schedules reveal that MiaPaCa-2 cells are more sensitive to the drug applied. These results demonstrate that further development on the device will provide a promising novel platform for individualized disease treatment in future medicine as well as for automatic in vitro assays in drug development industry.

Dissecting the phenotypes of Plk1 inhibition in cancer cells using novel kinase inhibitory chemical CBB2001

Polo-like kinase 1 (Plk1) is a mitotic serine/threonine kinase and its kinase activity is closely interrelated to cell cycle progression, various types of cancer development and often correlates with poor prognosis. Thus, it is of prime importance to characterize the phenotypes of Plk1 inhibition in cells for drug development and clinical application. Here, we report a novel kinase inhibitory chemical, CBB2001, which specifically inhibited Plk1 kinase activity in vitro with an IC50 of 0.39 μM. In cervical carcinoma HeLa cells, we found that treatment of CBB2001 caused mitotic cell cycle arrest (EC50=0.72 μM) and induction of ‘polo’ cells (EC50=0.32 μM). Interestingly, the cell cycle arrest induced by CBB2001 was associated with accumulation of Plk1 (EC50=0.61 μM) and Geminin (EC50=0.43 μM) proteins, but distinct from the phenotypes induced by Aurora kinase inhibitors. The inhibitory effects of CBB2001 were phenocopied by RNA interferences of Plk1. We also confirmed the cell cycle inhibitory effects of CBB2001 in other cancer cells. Moreover, CBB2001 inhibited the growth of HeLa cells with an IC50 of 0.85 μM in MTT assays, which is better than that of reported Plk1 inhibitory chemicals ON01910 (IC50=6.46 μM) and LFM-A13 (IC50=37.36 μM). CBB2001 also inhibited mouse xenograft tumor growth. Furthermore, CBB2001 inhibited mitotic exit and delayed degradation of APC/C substrates, Geminin, Cyclin B1 and Aurora A. These specific phenotypes may serve as specific features for Plk1 inhibition and for Plk1-based clinic trials.

Analysis of Pirlimycin Residues in Beef Muscle, Milk, and Honey by a Biotin–Streptavidin-Amplified Enzyme-Linked Immunosorbent Assay

Food contamination by veterinary drug residues is a worldwide public health concern and requires continuous monitoring. In this study, we developed a biotin-streptavidin-amplified ELISA (BA-ELISA) using a produced monoclonal antibody for detecting pirlimycin residues in beef muscle, milk, and honey. The IC50 value of the BA-ELISA was 1.6 ng/mL for pirlimycin in buffer, and the sensitivity was improved 3 times compared to traditional ELISAs. The optimized BA-ELISA can be used to quantitate trace amounts of pirlimycin residues in beef muscle, milk, and honey. This method had limits of detection (LODs) of 4.45 μg/kg in beef muscle, 1.65 μg/L in milk, and 2.75 μg/kg in honey. The average recovery of the BA-ELISA ranged from 78 to 97%, and the coefficient of variation ranged from 5.3 to 13.5%. The developed BA-ELISA method was validated using LC-MS/MS, and the BA-ELISA can be used for routine screening analysis of pirlimycin residues.