Biocompatibility and characterization of polyglycerol-based thermoresponsive nanogels designed as novel drug-delivery systems and their intracellular localization in keratinocytes

Abstract

(2017) Biocompatibility and characterization of polyglycerol-based thermoresponsive nanogels designed as novel drug-delivery systems and their intracellular localization in keratinocytes, Nanotoxicology, 11:2, 267-277, DOI: 10.1080/17435390.2017 ABSTRACTNovel nanogels that possess the capacity to change their physico-chemical properties in response to external stimuli are promising drug-delivery candidates for the treatment of severe skin diseases. As thermoresponsive nanogels (tNGs) are capable of enhancing penetration through biological barriers such as the stratum corneum and are taken up by keratinocytes of human skin, potential adverse consequences of their exposure must be elucidated. In this study, tNGs were synthesized from dendritic polyglycerol (dPG) and two thermoresponsive polymers. tNG_dPG_tPG are the combination of dPG with poly(glycidyl methyl ether-co-ethyl glycidyl ether) (p(GME-co-EGE)) and tNG_dPG_pNIPAM the one with poly(N-isopropylacrylamide) (pNIPAM). Both thermoresponsive nanogels are able to incorporate high amounts of dexamethasone and tacrolimus, drugs used in the treatment of severe skin diseases. Cellular uptake, intracellular localization and the toxicological properties of the tNGs were comprehensively characterized in primary normal human keratinocytes (NHK) and in spontaneously transformed aneuploid immortal keratinocyte cell line from adult human skin (HaCaT). Laser scanning confocal microscopy revealed fluorescently labeled tNGs entered into the cells and localized predominantly within lysosomal compartments. MTT assay, comet assay and carboxy-H2DCFDA assay, demonstrated neither cytotoxic or genotoxic effects, nor any induction of reactive oxygen species of the tNGs in keratinocytes. In addition, both tNGs were devoid of eye irritation potential as shown by bovine corneal opacity and permeability (BCOP) test and red blood cell (RBC) hemolysis assay. Therefore, our study provides evidence that tNGs are locally well tolerated and underlines their potential for cutaneous drug delivery. ARTICLE HISTORY

Breaking the Barrier - Potent Anti-Inflammatory Activity following Efficient Topical Delivery of Etanercept using Thermoresponsive Nanogels

“…To date, it has been shown that both tNG_pNIPAM and tNG_tPG induce no specific toxicity in murine LC's or human keratinocytes. 63 , 64 However, a lack of cytotoxicity does not exclude immunogenicity. Though nanoparticle induced immunogenicity is desirable in certain instances -vaccine formulations for example 65 , 66 - further immune cell activation in inflammatory skin diseases is not.…”

“…Furthermore, studies with immune cells akin to those found resident with human skin showed no toxic or immunogenic potential from the ETR loaded tNGs. 29 …”

Ultrastructural and Molecular Analysis of Ribose-Induced Glycated Reconstructed Human Skin

“…Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT; Sigma Aldrich, München, Germany) reduction as previously described [ 38 ]. In brief, NHK (passage 3) and NHDF (passage 3) were isolated from therapeutically indicated circumcision with permission (ethical approval EA1/081/13).…”

Novel targeted drug delivery systems to minimize systemic immunosuppression in vascularized composite allotransplantation

“…In addition, smart DDS that are able to respond to the tissue environment have been described for IST delivery into the skin. Thermoresponsive nanogels loaded with tacrolimus [37,38] or pH-sensitive dexamethasone-loaded nanoparticles [16 && ] are only some of the examples showing improved skin penetration and efficacy.…”