In Vitro Bioeffects of Polyelectrolyte Multilayer Microcapsules Post-Loaded with Water-Soluble Cationic Photosensitizer.

Alexey V Ermakov,Olga A Inozemtseva,Maria N Antipina,Irina V Babushkina,Vladimir J Ulyanov,Sergei Belyakov,Roman A Verkhovskii,Dmitry A Gorin,Daria B Trushina,Evgeny A Lukyanets

doi:10.3390/pharmaceutics12070610

Abstract

Microencapsulation and targeted delivery of cytotoxic and antibacterial agents of photodynamic therapy (PDT) improve the treatment outcomes for infectious diseases and cancer. In many cases, the loss of activity, poor encapsulation efficiency, and inadequate drug dosing hamper the success of this strategy. Therefore, the development of novel and reliable microencapsulated drug formulations granting high efficacy is of paramount importance. Here we report the in vitro delivery of a water-soluble cationic PDT drug, zinc phthalocyanine choline derivative (Cholosens), by biodegradable microcapsules assembled from dextran sulfate (DS) and poly-l-arginine (PArg). A photosensitizer was loaded in pre-formed [DS/PArg]4 hollow microcapsules with or without exposure to heat. Loading efficacy and drug release were quantitatively studied depending on the capsule concentration to emphasize the interactions between the DS/PArg multilayer network and Cholosens. The loading data were used to determine the dosage for heated and intact capsules to measure their PDT activity in vitro. The capsules were tested using human cervical adenocarcinoma (HeLa) and normal human dermal fibroblast (NHDF) cell lines, and two bacterial strains, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Our results provide compelling evidence that encapsulated forms of Cholosens are efficient as PDT drugs for both eukaryotic cells and bacteria at specified capsule-to-cell ratios.

Highlights

Photodynamic therapy (PDT) is one of the modern methods for the treatment of cancer and infectious diseases that hold the promise of selective erasing of the pathologic area [1,2,3]
Poly(sodium 4-styrenesulfonate) (PSS, M = 70 kDa), a 20% w/w water solution of poly(diallyldimethylammonium chloride) (PDADMAC, M = 100–200 kDa), dextran sulfate, sodium salt (DS, M > 40,000), poly-l-arginine hydrochloride (PArg, M > 70,000), α-chymotrypsin from bovine pancreas, calcium chloride dihydrate, anhydrous sodium carbonate, ethylenediaminetetraacetic acid trisodium salt (EDTA), rhodamine 6G (RhD6G), fluorescein 5-isothiocyanate (FITC), phosphate-buffered saline (PBS), Dulbecco’s minimum essential medium (DMEM), fetal bovine serum (FBS), Alamar blue, and calcein-AM were purchased from Sigma-Aldrich
Images obtained by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and atomic force microscopy (AFM) in Figure 2 depict the

Summary

Introduction

Photodynamic therapy (PDT) is one of the modern methods for the treatment of cancer and infectious diseases that hold the promise of selective erasing of the pathologic area [1,2,3]. The photosensitizer produces free radicals and/or reactive oxygen species that kill the target pathogenic or cancer cells [4,5]. Micron or submicron-sized polymeric multilayer capsules (PMC) assembled on CaCO3 vaterite sacrificial templates via alternate adsorption of biodegradable polyelectrolytes represent the system of choice for the delivery of PDT drugs, owing to their long-term structural stability and low toxicity [14,15]. Advancements in the miniaturization of vaterite templates and their respectively assembled PMC [34,35,36] have eased a long-held concern about the ability of such capsules to penetrate tissues and cells for delivery of drugs via intravenous injections. PMC with the size of ~250 nm were internalized by macrophages and epithelial cells of the lungs and liver with efficacy higher than 75% when administered in mice through an injection into the tail vein [31]

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