Extended Release of Doxorubicin-Loaded 3DNA Nanocarriers from In-Situ Forming, Self-Assembled Hydrogels

Evaluation of Dose-Response Relationship in Novel Extended Release of Targeted Nucleic Acid Nanocarriers to Treat Secondary Cataracts

Purpose: The present study aimed to determine the dose-response relationship between targeted nanocarriers released from a novel, sustained release formulation and their ability to specifically deplete cells responsible for the development of posterior capsular opacification (PCO) in month-long, dynamic cell cultures. Methods: Injectable, thermosensitive poly(D,L-lactic-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(D,L-lactic-co-glycolic acid) triblock copolymer hydrogels were loaded with either a low or a high dose of doxorubicin-loaded antibody-targeted nanocarriers (G8:3DNA:Dox). Human rhabdomyosarcoma cells, selected for their expression of PCO marker brain-specific angiogenesis inhibitor 1 (BAI1), were kept under dynamic media flow and received either a low or high dose of nanocarriers. Cells were fixed and stained at predetermined time points to evaluate targeted depletion of BAI1+ cells. Results: A lower dose of nanocarriers in hydrogel depleted BAI1+ cells at a slower rate than the higher dose, whereas both reached over 90% BAI1+ cellular nonviability at 28 days. Both treatment groups also significantly lowered the relative abundance of BAI1+ cells in the population compared with the control group. Conclusions: Controlled release of a lower dose of nanocarriers can still achieve therapeutically relevant effects in the prevention of PCO, while avoiding potential secondary effects associated with the administration of a higher dose.

Hollow Polyethyleneimine Nanoparticles with Drug Loaded DNA for Chemotherapeutic Applications

The next generation of anticancer agents are emerging from rationally designed nanostructured materials. This work involved the synthesis and characterization of novel hollow DNA-conjugated gold nanoparticles (DNA-AuNPs) for controlled drug delivery. Polyethyleneimine (PEI) was bound to AuNPs, forming polymer-shell nanoparticles. Dissolution of the gold core via iodine formed hollow core polymeric nanoparticles (HCPNPs) and a high density (85 molecules/particle) of DNA intercalated with daunorubicin was conjugated. Particles were spherical with an average diameter of 105.7±17.3 nm and zeta potential of 20.4±3.54 mV. We hypothesize the DNA backbone electrostatically condensed to the primary amines on the surface of the particle toroidally, weaving itself within the polymer shell. During the DNA intercalation process, increasing the ionic concentration and decreasing the amine/phosphate ratio 10-fold increased drug intercalation 64 % and 61 %, respectively, allowing us to determine the optimal method of particle synthesis. As intercalation sites increased with increasing DNA strand length, drug loading increased. An average of 874±40.1 daunorubicin molecules were loaded per HCPNP. HCPNPs with drug intercalated DNA have strong potential to be clinically efficacious drug delivery vehicles due to the versatility of DNA and high drug loading capacities.

Nanotechnology based drug delivery systems for the treatment of anterior segment eye diseases

Diseases affecting the anterior segment of the eye are the primary causes of vision impairment and blindness globally. Drug administration through the topical ocular route is widely accepted because of its user/patient friendliness - ease of administration and convenience. However, it remains a significant challenge to efficiently deliver drugs to the eye through this route because of various structural and physiological constraints that restrict the distribution of therapeutic molecules into the ocular tissues. The bioavailability of topically applied ocular medications such as eye drops is typically less than 5%. Developing novel delivery systems to increase the retention time on the ocular surfaces and permeation through the cornea is one of the approaches adopted to boost the bioavailability of topically administered medications. Drug delivery systems based on nanotechnology such as micelles, nanosuspensions, nanoparticles, nanoemulsions, liposomes, dendrimers, niosomes, cubosomes and nanowafers have been investigated as effective alternatives to conventional ocular delivery systems in treating diseases of the anterior segment of the eye. This review discussed different nanotechnology-based delivery systems that are currently investigated for treating and managing diseases affecting the anterior ocular tissues. We also looked at the challenges in translating these systems into clinical use and the prospects of nanocarriers as a vehicle for the delivery of phytoactive compounds to the anterior segment of the eye.

Sustained Release of Antibody-Conjugated DNA Nanocarriers from a Novel Injectable Hydrogel for Targeted Cell Depletion to Treat Cataract Posterior Capsule Opacification

Purpose: To compare a novel, sustained release formulation and a bolus injection of a targeted nanocarrier for the ability to specifically deplete cells responsible for the development of posterior capsule opacification (PCO) in week-long, dynamic cell cultures. Methods: A novel, injectable, thermosensitive poly(D,L-lactic-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(D,L-lactic-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymer hydrogel was engineered for the sustained release of targeted, nucleic acid nanocarriers loaded with cytotoxic doxorubicin (G8:3DNA:Dox). Human rhabdomyosarcoma (RD) cells were used due to their expression of brain-specific angiogenesis inhibitor 1 (BAI1), a specific marker for the myofibroblasts responsible for PCO. Under constant media flow, nanocarriers were injected into cell cultures as either a bolus or within the hydrogel. Cells were fixed and stained every other day for 7 days to compare targeted depletion of BAI1⁺ cells. Results: The formulation transitions to a gel at physiological temperatures, is optically clear, noncytotoxic, and can release G8:3DNA:Dox nanocarriers for up to 4 weeks. In RD cell cultures, G8:3DNA:Dox nanocarriers specifically eliminated BAI1⁺ cells. The bolus nanocarrier dose showed significantly reduced cell depletion overtime, while the sustained release of nanocarriers showed increased cell depletion over time. By day 7, <2% of BAI1⁺ cells were depleted by the bolus injection and 74.2% BAI1⁺ cells were targeted by the sustained release of nanocarriers. Conclusions: The sustained release of nanocarriers from the hydrogel allows for improved therapeutic delivery in a dynamic system. This method can offer a more effective and efficient method of prophylactically treating PCO after cataract surgery.