Multi-functional nanocarriers for targeted delivery of drugs and genes.

In this review article, we describe the different nano-platforms developed in our laboratory at Northeastern University in Boston, MA for the targeted delivery of drugs and genes. Special emphasis is placed on nano-platforms that offer opportunities for multi-functionalization to allow for targeted stimuli-responsive and/or simultaneous strategic delivery of multiple drugs, genes, as well as the combination of therapeutic systems with image contrast enhancers. Polymeric and lipid-based nanocarriers can provide versatile platforms for the delivery of multiple pharmacological agents, specifically to enhance therapeutic effect and overcome drug resistance in cancer. In addition, polymeric nanoparticles and nanoparticles-in-microsphere oral system (NiMOS) are useful for systemic and oral gene therapy, respectively.

Development of novel biodegradable polymeric nanoparticles-in-microsphere formulation for local plasmid DNA delivery in the gastrointestinal tract.

There is a critical need for development of novel delivery systems to facilitate the translation of nucleic acid-based macromolecules into clinically-viable therapies. The aim of this investigation was to develop and evaluate a novel nanoparticles-in-microsphere oral system (NiMOS) for gene delivery and transfection in specific regions of the gastrointestinal (GI) tract. Plasmid DNA, encoding for the enhanced green fluorescent protein (EGFP-N1), was encapsulated in type B gelatin nanoparticles. NiMOS were prepared by further protecting the DNA-loaded nanoparticles in a poly(epsilon-caprolactone) (PCL) matrix to form microspheres of less than 5.0 microm in diameter. In order to evaluate the biodistribution following oral administration, radiolabeled ((111)In-labeled) gelatin nanoparticles and NiMOS were administered orally to fasted Balb/C mice. The results of biodistribution studies showed that, while gelatin nanoparticles traversed through the GI tract fairly quickly with more than 54% of the administered dose per gram localizing in the large intestine at the end of 2 h, NiMOS resided in the stomach and small intestine for relatively longer duration. Following oral administration of EGFP-N1 plasmid DNA at 100 microg dose in the control and test formulations, the quantitative and qualitative results presented in this study provide the necessary evidence for transfection potential of NiMOS upon oral administration. After 5 days post-administration, transgene expression in the small and large intestine of mice was observed. Based on these results, NiMOS show significant potential as novel gene delivery vehicle for therapeutic and vaccination purposes.

Polymeric nano- and microparticle technologies for oral gene delivery.

Gene therapy refers to local or systemic administration of a nucleic acid construct that can prevent, treat and even cure diseases by changing the expression of genes that are responsible for the pathological condition. Oral gene therapy has significant promise for treatment of local diseases such as inflammatory bowel disease and for systemic absorption of the expressed protein therapeutics. In addition, efficient oral delivery of DNA vaccines can have significant impact in disease prevention. The use of polymeric gene delivery vectors promises the translation of this experimental medical concept into clinical reality. This review addresses the challenges and opportunities in the development of polymer-based nano- and microparticle technologies for oral gene therapy. Specifically, the discussion is focused on different synthetic and natural polymers used for formulating nano- and microparticle technologies and the use of these delivery systems for oral DNA administration for therapeutic and vaccination purposes.

Gastrointestinal distribution and in vivo gene transfection studies with nanoparticles-in-microsphere oral system (NiMOS).

The aim of this investigation was to develop and evaluate a novel nanoparticles-in-microsphere oral system (NiMOS) for gene delivery and transfection in specific regions of the gastrointestinal (GI) tract. Plasmid DNA, encoding either for beta-galactosidase (CMV-betagal) or enhanced green fluorescent protein (EFGP-N1), was encapsulated in type B gelatin nanoparticles. NiMOS were prepared by further protecting the DNA-loaded nanoparticles in a poly(epsilon-caprolactone) (PCL) matrix to form microspheres of less than 5.0 microm in diameter. In order to evaluate the biodistribution following oral administration, radiolabeled ((111)In-labeled) gelatin nanoparticles and NiMOS were administered orally to fasted Wistar rats. The results of biodistribution studies showed that, while gelatin nanoparticles traversed through the GI tract fairly quickly with more than 85% of the administered dose per gram localizing in the large intestine within the first hour, NiMOS resided in the stomach and small intestine for relatively longer duration. Following oral administration of CMV-betagal or EFGP-N1 plasmid DNA at 100 microg dose in the control and test formulations, the qualitative results presented in this study provide the proof-of-concept for the transfection capability of NiMOS upon oral administration. After 5 days post-administration, we observed transgene expression in the small and large intestine of rats. Based on these preliminary results, NiMOS show significant potential as novel gene delivery vehicle for therapeutic and vaccination purposes.

Formulation optimization for the nanoparticles-in-microsphere hybrid oral delivery system using factorial design.

The tremendous progress witnessed in the field of biotechnology with respect to discovery of therapeutic and antigenic proteins has propelled the need for development of suitable oral delivery devices for these and other macromolecules. In this study, we report the encapsulation of fluorescein isothiocyanate (FITC)-labeled gelatin nanoparticles into poly(epsilon-caprolactone) (PCL) microsphere (nanoparticle-in-microsphere oral delivery system, NiMOS) by double emulsion like technique and the influence of variables such as polymer concentration in organic phase, amount of nanoparticles added as internal phase, and the speed of homogenization on particle size of NiMOS using a 3(3) randomized full factorial design. A statistical model with interaction terms was derived to predict the particle size of the hybrid system. The results from multiple linear regression analysis and Student's t-test revealed that for obtaining large particles of NiMOS, a high polymer concentration and low speed of homogenization was necessary. In contrast, to obtain particles of smaller size, high speed of homogenization was found to be very important. The mathematical model obtained was validated for prediction of particle size. The encapsulation of gelatin nanoparticles in PCL microsphere was confirmed by fluorescent microscopy. Based on the statistical model we were also successful in producing NiMOS of less than 10 mum in size, which could be used as oral delivery system for therapeutic and antigenic macromolecules.