Neuroprotective Effect of siRNA Entrapped in Hyaluronic Acid-Coated Lipoplexes by Intravitreal Administration

Nanoparticle-Based gene therapy strategies in retinal delivery

Vision loss and blindness are significant issues in both developed and developing countries. There are a wide variety of aetiologies that can cause vision loss, which are outlined in this review. Although treatment has significantly improved over time for some conditions, nearly half of all people with vision impairment are left untreated. Gene delivery is an emerging field that may assist with the treatment of some of these difficult to manage forms of vision loss. Here we review how a component of nanotechnology-based, non-viral gene delivery systems are being applied to help resolve vision impairment. This review focuses on the use of lipid and polymer nanoparticles, and quantum dots as gene delivery vectors to the eye. Finally, we also highlight some emerging technologies that may be useful in this discipline.

Advances in nanomedicine for retinal drug delivery: overcoming barriers and enhancing therapeutic outcomes

Nanomedicine offers a promising avenue for improving retinal drug delivery, effectively addressing challenges associated with ocular diseases like age-related macular degeneration and diabetic retinopathy. Nanoparticles, with their submicron size and customisable surface properties, enable enhanced permeability and retention within retinal tissues, supporting sustained drug release and minimising systemic side effects. Nanostructured scaffolds further provide a supportive environment for retinal cell growth and tissue regeneration, crucial for treating degenerative conditions. Additionally, advanced nanodevices facilitate real-time monitoring and controlled drug release, marking significant progress in retinal therapy. This study reviews recent advancements in nanomedicine for retinal drug delivery, critically analysing design innovations, therapeutic benefits, and limitations of these systems. By advancing nanotechnology integration in ocular therapies, this field holds strong potential for overcoming current barriers, ultimately improving patient outcomes and quality of life.

Development and Characterization of Modified Chitosan Lipopolyplex for an Effective siRNA Delivery

Cytotoxicity, speedy degradation, and limited cellular absorption are the foremost features influencing the successful delivery of RNAs. Chitosan (Cs) is a polymer that offers an advantage due to its bio-compatibility and biodegradable nature, making it an ideal polycationic vector for delivering siRNA. In this study, chitosan has been modified with arginine in order to increase its encapsulation of siRNA and improve cellular absorption. It was discovered that arginine and guanidino moieties could transport through membranes of cells and play an important part in membrane permeability. FTIR and 13C NMR were used to characterize the complex. These chitosan-arginine (CsAr) siRNA complexes are further encapsulated in anionic DPPC/cholesterol liposomes to combine the effects of liposome-chitosan-arginine complexes called lipopolyplexes (LCAr). Formed LCAr were investigated for their lipid/CsAr-siRNA ratios, size, zeta-potential, heparin, and serum RNase stability by agarose gel retardation, and cell uptake efficiency compared to their "parent" polyplexes. Results revealed complete lipidation of CsAr-siRNA polyplexes at lipid mass ratio 10 resulting in lipopolyplexes in the 120 to 230nm range. Polyplex entrapped ~70% of siRNA, whereas lipidation increases siRNA encapsulation to ~95%. Developed LCAr showed ~4 times less hemolytic potential as compared to the parent polyplexes at the highest siRNA dose. The CsAr-siRNA and its lipid-coated form showed enhanced cellular association as compared to the marketed Lipofectamine 2000 proving its effectiveness in siRNA delivery. CsAr-liposome conjugation is simple and safe, and serves as a robust carrier for gene transport in physiological situations without compromising transfection efficacy.

Nanotechnology-based ocular drug delivery systems: recent advances and future prospects

Ocular drug delivery has constantly challenged ophthalmologists and drug delivery scientists due to various anatomical and physiological barriers. Static and dynamic ocular barriers prevent the entry of exogenous substances and impede therapeutic agents' active absorption. This review elaborates on the anatomy of the eye and the associated constraints. Followed by an illustration of some common ocular diseases, including glaucoma and their current clinical therapies, emphasizing the significance of drug therapy in treating ocular diseases. Subsequently, advances in ocular drug delivery modalities, especially nanotechnology-based ocular drug delivery systems, are recommended, and some typical research is highlighted. Based on the related research, systematic and comprehensive characterizations of the nanocarriers are summarized, hoping to assist with future research. Besides, we summarize the nanotechnology-based ophthalmic drugs currently on the market or still in clinical trials and the recent patents of nanocarriers. Finally, inspired by current trends and therapeutic concepts, we provide an insight into the challenges faced by novel ocular drug delivery systems and further put forward directions for future research. We hope this review can provide inspiration and motivation for better design and development of novel ophthalmic formulations.

Next-Generation Nanomedicine Approaches for the Management of Retinal Diseases

Retinal diseases are one of the leading causes of blindness globally. The mainstay treatments for these blinding diseases are laser photocoagulation, vitrectomy, and repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) or steroids. Unfortunately, these therapies are associated with ocular complications like inflammation, elevated intraocular pressure, retinal detachment, endophthalmitis, and vitreous hemorrhage. Recent advances in nanomedicine seek to curtail these limitations, overcoming ocular barriers by developing non-invasive or minimally invasive delivery modalities. These modalities include delivering therapeutics to specific cellular targets in the retina, providing sustained delivery of drugs to avoid repeated intravitreal injections, and acting as a scaffold for neural tissue regeneration. These next-generation nanomedicine approaches could potentially revolutionize the treatment landscape of retinal diseases. This review describes the availability and limitations of current treatment strategies and highlights insights into the advancement of future approaches using next-generation nanomedicines to manage retinal diseases.

Every nano-step counts: a critical reflection on do's and don'ts in researching nanomedicines for retinal gene therapy

INTRODUCTION

Retinal disease affects millions of people worldwide, generating a massive social and economic burden. Current clinical trials for retinal diseases are dominated by gene augmentation therapies delivered with recombinant viruses as key players. As an alternative, nanoparticles hold great promise for the delivery of nucleic acid therapeutics as well. Nevertheless, despite numerous attempts, 'nano' is in practice not as successful as aspired and major breakthroughs in retinal gene therapy applying nanomaterials are yet to be seen.

AREAS COVERED

In this review, we summarize the advantages of nanomaterials and give an overview of nanoparticles designed for retinal nucleic acid delivery up to now. We furthermore critically reflect on the predominant issues that currently limit nano to progress to the clinic, where faulty study design and the absence of representative models play key roles.

EXPERT OPINION

Since the current approach of in vitro - in vivo experimentation is highly inefficient and creates misinformation, we advocate for a more prominent role for ex vivo testing early on in nanoparticle research. In addition, we elaborate on several concepts, including systematic studies and open science, which could aid in pushing the field of nanomedicine beyond the preclinical stage.