High efficient encapsulation of plasmid DNA in PLGA microparticles by organic phase self-emulsification

Preservation of DNA for data storage

The preservation of DNA has attracted significant interest of scientists in diverse research fields from ancient biological remains to the information field. In light of the different DNA safekeeping requirements (e.g., storage time, storage conditions) in these disparate fields, scientists have proposed distinct methods to maintain the DNA integrity. Specifically, DNA data storage is an emerging research, which means that the binary digital information is converted to the sequences of nucleotides leading to dense and durable data storage in the form of synthesized DNA. The intact preservation of DNA plays a significant role because it is closely related to data integrity. This review discusses DNA preservation methods, aiming to confirm an appropriate one for synthetic oligonucleotides in DNA data storage. First, we analyze the impact factors of the DNA long-term storage, including the intrinsic stability of DNA, environmental factors, and storage methods. Then, the benefits and disadvantages of diverse conservation approaches (e.g., encapsulation-free, chemical encapsulation) are discussed. Finally, we provide advice for storing non-genetic information in DNA in vitro. We expect these preservation suggestions to promote further research that may extend the DNA storage time.

The bibliography includes 99 references.

Hybrid polymeric-protein nano-carriers (HPPNC) for targeted delivery of TGFβ inhibitors to hepatocellular carcinoma cells

TGFβ1 pathway antagonists have been considered promising therapies to attenuate TGFβ downstream signals in cancer cells. Inhibiting peptides, as P-17 in this study, are bound to either TGFβ1 or its receptors, blocking signal transduction. However, for efficient use of these TGFβ1antagonist as target therapeutic tools, improvement in their delivery is required. Here, a plasmid carrying specific shDNA (SHT-DNA), small interfering RNA (siRNA), and the peptide (P-17) were loaded separately into folic acid (FA)-functionalized nano-carriers made of Bovine Serum Albumin (BSA). The two building blocks of the carrier, (BSA and FA) were used because of the high affinity of albumin for liver and for the overexpression of folate receptors on the membrane of hepatocellular carcinoma cells. The empty and the encapsulated carriers were thoroughly investigated to characterize their structure, to evaluate the colloidal stability and the surface functionalization. The entrapment of SHT-DNA, siRNA and P-17, respectively, was demonstrated by morphological and quantitative analysis. Finally, cellular studies were performed to assess the targeting efficiency of the hybrid carriers. These vectors were used because of the high affinity of albumin for liver and for the overexpression of folate receptors on the membrane hepatocellular carcinoma cells. The empty and the encapsulated carriers were thoroughly investigated to characterize their structure, to evaluate the colloidal stability and the surface functionalization. The entrapment of SHT-DNA, siRNA and P-17, respectively, was demonstrated by morphological and quantitative analysis. A novel fabrication of Hybrid Polymeric-Protein Nano-Carriers (HPPNC) for delivering TGF β1 inhibitors to HCC cells has been developed. SHT-DNA, siRNA and P-17 have been successfully encapsulated. TGF β1 inhibitors-loaded HPPNC were efficiently uptaken by HLF cells.

Modified nanoprecipitation method to fabricate DNA-loaded PLGA nanoparticles

OBJECTIVE

The objective of this study was to formulate DNA-loaded poly(d,l-lactide-co-glycotide) (PLGA) nanoparticles by a modified nanoprecipitation method.

METHODS

DNA-loaded PLGA nanoparticles were prepared by the modified nanoprecipitation method and the double emulsion/solvent evaporation method. The characterizations of DNA-loaded nanoparticles such as entrapment efficiency, morphology, particle size, zeta potential, structural integrity of the loaded DNA, and stability of the loaded DNA in PLGA nanoparticles against DNase I, in vitro release, cell viability and in vitro transfection capability were investigated.

RESULTS

The resulted PLGA nanoparticles by the modified nanoprecipitation method had uniform spherical shape, narrow size distribution with average particles size near 200 nm, negative zeta potential of -12.6 mV at pH 7.4, and a sustained-release property in vitro. Plasmid DNA could be efficiently encapsulated into PLGA nanoparticles (> 95%) without affecting its intact conformation using this modified nanoprecipitation method, which was superior to the double emulsion/solvent evaporation method. The PLGA nanoparticles were much safer to A549 cell compared to commercial Lipofectamine 2000 and could successfully transfer plasmid-enhanced green fluorescent protein into A549 cells.

CONCLUSION

In conclusion, the modified nanoprecipitation method could be applied as an efficient way to fabricate DNA-loaded PLGA nanoparticles instead of the conventional double emulsion/solvent evaporation method.

Formulating poly(lactide-co-glycolide) particles for plasmid DNA delivery

Biodegradable poly(lactide-co-glycolide) (PLGA) particles have shown significant potential for sustained and targeted delivery of several pharmaceutical agents, including plasmid DNA (pDNA). Here, we survey current approaches to PLGA particle preparation for pDNA delivery and discuss recent progress on optimizing formulation development.

Poly(ethylene glycol)/poly(ε-caprolactone) diblock copolymeric nanoparticles for non-viral gene delivery: The role of charge group and molecular weight in particle formation, cytotoxicity and transfection

Two types of nanoparticles containing pGL3-Control (plasmid DNA) were prepared using nonionic amphiphlic block copolymers and ionic amphiphilic block copolymers containing a terminal cationic group to investigate the effect of charge on the vehicle properties for systemic gene delivery. Methoxy poly(ethylene glycol) (MPEG)/poly(epsilon-caprolactone) (PCL) diblock copolymers were synthesized by the ring-opening polymerizatrion of epsilon-caprolactone in the presence of a catalyst-free MPEG homopolymer. The hydroxy groups of MPEG/PCL block copolymer were then modified into an amine group to synthesize an amine-terminated MPEG/PCL diblock copolymer (AMPEG/PCL). DNA was incorporated into the polymeric nanoparticles by physical entrapment and electrostatic interaction. All nanoparticle samples exhibited spherical structures and although their sizes increased slightly after DNA-loading, they remained less than 160 nm. The AMPEG/PCL nanoparticles exhibited smaller particle sizes than the MPEG/PCL nanoparticles of the same molecular weight after DNA-loading. The optimum mixing ratio of MPEG/PCL and AMPEG/PCL copolymers to DNA ranged from 4:1 to 1:2 depending on the molecular weight of the block copolymer, the composition of MPEG and PCL and terminal amine group. Based on in vitro cytotoxicity tests, the DNA-loaded MPEG/PCL and AMPEG/PCL nanoparticles did not induce any remarkable cytotoxicity against normal human fibroblasts. Transfection efficiencies of DNA-loaded nanoparticles were improved about 3.4 - 12.9 times under serum conditions.

DNA delivery from photocrosslinked PEG hydrogels: encapsulation efficiency, release profiles, and DNA quality

Sustained DNA delivery from polymer matrices provides a means for enhanced and prolonged gene therapy; however, limitations exist with respect to tailoring the DNA release profiles and maintaining the quality of the encapsulated DNA over time. To address these issues, PEG-based macromolecular monomers were photopolymerized to produce hydrogels with various degradation rates to control the DNA release profiles. Photocrosslinked PEG-based hydrogels were designed that released DNA for periods of 6-100 days with either nearly linear or delayed burst release profiles. Plasmid DNA was released primarily in the relaxed and supercoiled forms, and the released DNA showed high biological activity in plated cell cultures. The addition of both chemical and physical protective agents helped preserve the supercoiled form of the plasmid DNA during photoencapsulation (up to 75% compared to non-encapsulated plasmid controls), thereby enhancing the biological activity of the released DNA.

Nanoassembly of Biodegradable Microcapsules for DNA Encasing

A new microcontainer for DNA delivery based on biocompatible poly[beta-glucuronic acid-(1 --> 3)-N-acetyl-beta-galactosamine-6-sulfate-(1 --> 4)](chondroitin sulfate)/poly(-l-arginine) microcapsules with 40 nm thick molecularly organized shell was proposed. DNA molecules were deposited as DNA/sperimidine complex on the surface of template 4 mum core particles followed by layer-by-layer nanoassembly of protective chondroitin sulfate/poly(-l-arginine) shell. After template core dissolution, DNA molecules were captured inside microcapsules retaining a natural double-helix structure. The developed DNA encapsulation approach can be employed for targeted delivery of plasmid DNA in living cells.