Glycol Chitosan-Poly(lactic acid) Conjugate Nanoparticles Encapsulating Ciprofloxacin: A Mucoadhesive, Antiquorum-Sensing, and Biofilm-Disrupting Treatment Modality for Bacterial Keratitis.

Bacterial keratitis (BK) causes visual morbidity/blindness if not treated effectively. Here, ciprofloxacin (CIP)-loaded nanoparticles (NPs) using glycol chitosan (GC) and poly(lactic acid) (PLA) conjugate at three different ratios (CIP@GC(PLA) NPs (1:1,5,15)) were fabricated. CIP@GC(PLA) NPs (1:1) were more effective than other tested ratios, indicating the importance of optimal hydrophobic/hydrophilic balance for corneal penetration and preventing bacterial invasion. The CIP@GC(PLA) (NPs) (1:1) realized the highest association with human corneal epithelial cells, which were nonirritant to the hen's egg-chorioallantoic membrane test (HET-CAM test) and demonstrated significant antibacterial response in the in vitro minimum inhibitory, bactericidal, live-dead cells, zone of inhibition, and biofilm inhibition assays against the keratitis-inducing pathogen Pseudomonas aeruginosa. The antiquorum sensing activity of GC has been explored for the first time. The NPs disrupted the bacterial quorum sensing by inhibiting the production of virulence factors, including acyl homoserine lactones, pyocyanin, and motility, and caused significant downregulation of quorum sensing associated genes. In the in vivo studies, CIP@GC(PLA) NPs (1:1) displayed ocular retention in vivo (∼6 h) and decreased the opacity and the bacterial load effectively. Overall, the CIP@GC(PLA) NP (1:1) is a biofilm-disrupting antiquorum sensing treatment regimen with clinical translation potential in BK.

Cationized gelatin-sodium alginate polyelectrolyte nanoparticles encapsulating moxifloxacin as an eye drop to treat bacterial keratitis.

A mucoadhesive polyelectrolyte complex (PEC) nanoparticles were developed for ocular moxifloxacin (Mox) delivery in Bacterial Keratitis (BK). Moxifloxacin-loaded G/CG-Alg NPs were prepared by an amalgamation of cationic polymers (gelatin (G)/cationized gelatin (CG)), and anionic polymer (sodium alginate (Alg)) along with Mox respectively. Mox@CG-Alg NPs were characterized for physicochemical parameters such as particle size (DLS technique), morphology (SEM analysis), DSC, XRD, encapsulation efficiency, drug loading, mucoadhesive study (by texture analyzer), mucin turbidity, and viscosity assessment. The NPs uptake and toxicity of the formulation were analyzed in the Human Corneal Epithelial (HCE) cell line and an ocular irritation study was performed on the HET-CAM. The results indicated that the CG-Alg NPs, with optimal size (217.2 ± 4 nm) and polydispersity (0.22 ± 0.05), have shown high cellular uptake in monolayer and spheroids of HCE. The drug-loaded formulation displayed mucoadhesiveness, trans-corneal permeation, and sustained the release of the Mox. The anti-bacterial efficacy studied on planktonic bacteria/biofilms of P. aeruginosa and S. aureus (in vitro) indicated that the Mox@CG-Alg NPs displayed low MIC, higher zone of bacterial growth inhibition, and cell death compared to free Mox. A significant reduction of bacterial load was observed in the BK-induced mouse model.

Chitosan oligosaccharide/pluronic F127 micelles exhibiting anti-biofilm effect to treat bacterial keratitis.

Mono or dual chitosan oligosaccharide lactate (COL)-conjugated pluronic F127 polymers, FCOL1 and FCOL2 were prepared, self-assembled to form micelles, and loaded with gatifloxacin. The Gati@FCOL1/Gati@FCOL2 micelles preparation process was optimized by QbD analysis. Micelles were characterized thoroughly for size, CMC, drug compatibility, and viscosity by GPC, DLS, SEM, IR, DSC, and XRD. The micelles exhibited good cellular uptake in both monolayers and spheroids of HCEC. The antibacterial and anti-biofilm activities of the micelles were evaluated on P. aeruginosa and S. aureus. The anti-quorum sensing activity was explored in P. aeruginosa by analyzing micelles' ability to produce virulence factors, including AHLs, pyocyanin, and the motility behavior of the organism. Gati@FCOL2 Ms was mucoadhesive, cornea-penetrant, antibacterial, and inhibited the biofilm formation by P. aeruginosa and S. aureus significantly more than Gati@FCOL1. A significant reduction in bacterial load in mice cornea was observed after Gati@FCOL2 Ms-treatment to the P. aeruginosa-induced bacterial keratitis-infected mice.

3D-Printed Inherently Antibacterial Contact Lens-Like Patches Carrying Antimicrobial Peptide Payload for Treating Bacterial Keratitis.

Delivery of therapeutic agents through contact lenses-like patches is a promising strategy to achieve significant bioavailability with negligible eye drainage. The present study investigates the preparation and 3D printing of mucoadhesive gelatin methacryloyl (GelMA)/chitosan methacryloyl (ChiMA) hydrogels to fabricate them as contact lens-like patches (CLP) loaded with antimicrobial peptide, S100A12 (AMP) for treating bacterial keratitis (BK). Extrusion technology is used to print the patches layer by layer to form a hemispherical scaffold suitable for eyewear, and 3D-printed CLP is crosslinked using Irgacure 2959 under UV light. The results from the in vivo experiment conducted on Pseudomonas aeruginosa-infected BK rabbit model after the treatment with AMP-loaded CLP have shown a significant decrease in bacterial load when plated for CFU. The newly developed delivery system containing AMP has great potential to overcome the treatment challenges of multidrug resistance (MDR) in bacteria and eliminate the frequent dosing associated with eye drops. The presence of chitosan in the formulation provides a synergetic effect on the AMP in disrupting bacterial biofilms. The ease of using 3D printing will open new avenues for optimizing the dosage depending on the severity of the BK in the patients, which can be used as personalized medicine.

Dual-Drug-Loaded Topical Delivery of Photodynamically Active Lipid-Based Formulation for Combination Therapy of Cutaneous Melanoma.

Topical administration of anti-cancer drugs along with photodynamically active molecules is a non-invasive approach, which stands to be a promising modality for treating aggressive cutaneous melanomas with the added advantage of high patient compliance. However, the efficiency of delivering drugs topically is limited by several factors, such as penetration of the drug across skin layers at the tumor site and limited light penetrability. In this study, curcumin, an active anti-cancer agent, and chlorin e6, a photoactivable molecule, were encapsulated into lipidic nanoparticles that produced reactive oxygen species (ROS) when activated at 665 nm by near-infrared (NIR) light. The optimized lipidic nanoparticle containing curcumin and chlorin e6 exhibited a particle size of less than 100 nm. The entrapment efficiency for both molecules was found to be 81%. The therapeutic efficacy of the developed formulation was tested on B16F10 and A431 cell lines via cytotoxicity evaluation, combination index, cellular uptake, nuclear staining, DNA fragmentation, ROS generation, apoptosis, and cell cycle assays under NIR irradiation (665 nm). Co-delivering curcumin and chlorin e6 exhibited higher cellular uptake, better cancer growth inhibition, and pronounced apoptotic events compared to the formulation having the free drug alone. The study results depicted that topical application of this ROS-generating dual-drug-loaded lipidic nanoparticles incorporated in SEPINEO gel achieved better permeation (80 ± 2.45%) across the skin, and exhibited the improved skin retention and a synergistic effect as well. The present work introduces photo-triggered ROS-generating dual-drug-based lipidic nanoparticles, which are simple and efficient to develop and exhibit synergistic therapeutic effects against cutaneous melanoma.

Chitosan-poly(lactide-co-glycolide)/poloxamer mixed micelles as a mucoadhesive thermo-responsive moxifloxacin eye drop to improve treatment efficacy in bacterial keratitis.

A mucoadhesive self-assembling polymeric system was developed to carry moxifloxacin (M) for treating bacterial keratitis (BK). Chitosan-PLGA (C) conjugate was synthesized, and poloxamers (F68/127) were mixed in different proportions (1: 5/10) to prepare moxifloxacin (M)-encapsulated mixed micelles (M@CF68/127(5/10)Ms), including M@CF68(5)Ms, M@CF68(10)Ms, M@CF127(5)Ms, and M@CF127(10)Ms. The corneal penetration and mucoadhesiveness were determined biochemically, in vitro using human corneal epithelial (HCE) cells in monolayers and spheroids, ex vivo using goat cornea, and in vivo via live-animal imaging. The antibacterial efficacy was studied on planktonic biofilms of P. aeruginosa and S. aureus (in vitro) and Bk-induced mice (in vivo). Both M@CF68(10)Ms and M@CF127(10)Ms demonstrated high cellular uptake, corneal retention, muco-adhesiveness, and antibacterial effect, with M@CF127(10)Ms exhibiting superior therapeutic effects in P. aeruginosa and S. aureus-infected BK mouse model by reducing the corneal bacterial load and preventing corneal damage. Therefore, the newly developed nanomedicine is promising for clinical translation in treating BK.

Nanotherapeutic Intervention in Photodynamic Therapy for Cancer.

The clinical need for photodynamic therapy (PDT) has been growing for several decades. Notably, PDT is often used in oncology to treat a variety of tumors since it is a low-risk therapy with excellent selectivity, does not conflict with other therapies, and may be repeated as necessary. The mechanism of action of PDT is the photoactivation of a particular photosensitizer (PS) in a tumor microenvironment in the presence of oxygen. During PDT, cancer cells produce singlet oxygen (1O2) and reactive oxygen species (ROS) upon activation of PSs by irradiation, which efficiently kills the tumor. However, PDT's effectiveness in curing a deep-seated malignancy is constrained by three key reasons: a tumor's inadequate PS accumulation in tumor tissues, a hypoxic core with low oxygen content in solid tumors, and limited depth of light penetration. PDTs are therefore restricted to the management of thin and superficial cancers. With the development of nanotechnology, PDT's ability to penetrate deep tumor tissues and exert desired therapeutic effects has become a reality. However, further advancement in this field of research is necessary to address the challenges with PDT and ameliorate the therapeutic outcome. This review presents an overview of PSs, the mechanism of loading of PSs, nanomedicine-based solutions for enhancing PDT, and their biological applications including chemodynamic therapy, chemo-photodynamic therapy, PDT-electroporation, photodynamic-photothermal (PDT-PTT) therapy, and PDT-immunotherapy. Furthermore, the review discusses the mechanism of ROS generation in PDT advantages and challenges of PSs in PDT.