Polymer nanogels: A versatile nanoscopic drug delivery platform

Abstract

In this review we put the spotlight on crosslinked polymer nanogels, a promising platform that has the characteristics of an “ideal” drug delivery vehicle. Some of the key aspects of drug delivery vehicle design like stability, response to biologically relevant stimuli, passive targeting, active targeting, toxicity and ease of synthesis are discussed. We discuss several delivery systems in this light and highlight some examples of systems, which satisfy some or all of these design requirements. In particular, we point to the advantages that crosslinked polymeric systems bring to drug delivery. We review some of the synthetic methods of nanogel synthesis and conclude with the diverse applications in drug delivery where nanogels have been fruitfully employed.

Advanced drug delivery nanosystems (aDDnSs): a mini-review

“…Nanogels can contain and protect drugs (and nucleotide therapeutics) and regulate their release by incorporating high-affinity functional groups, stimuli-responsive conformations and biodegradable bonds into the polymeric network (Vinogradov, 2007;Kabanov & Vinogradov, 2009;Sasaki & Akiyoshi, 2010;Chacko et al, 2012;Moya-Ortega et al, 2012). Similar to other nanoparticulate DDS, nanogels can easily be administered in liquid form for parenteral drug delivery.…”

“…The nanoscale size of nanogels gives them a high specific surface area that is available for further bioconjugation of active targeting agents and macromolecules. Drug release properties, biodistribution and excretion can be modulated through size adjustments, too (Vinogradov, 2007;Kabanov & Vinogradov, 2009;Sasaki & Akiyoshi, 2010;Chacko et al, 2012;Moya-Ortega et al, 2012).…”

Advances in the application of nanotechnology in the diagnosis and treatment of gastrointestinal tumors

“…Kong et al (70) found that IRDye900-conjugated pullulan-cholesterol nanoprobe NIR-PNG exhibited the favorable characteristics of lower dispersion and longer retention in the SLN compared to diluted indocyanine green (ICG) and ICG/poly-γ-glutamic acid complex following injection into the stomachs of dogs and pigs (70). Nanogels may be controlled for various applications in drug delivery and may be tailored to exhibit exceptional stability, low cytotoxicity and higher blood compatibility (71,72). Nanogels containing 5-fluorouracil (5-FU) were developed to be utilized as a new colon-targeting drug carrier systems, owing to their excellent pH-sensitive release property and effectively reduced toxicity (73).…”

Preparation of pH-Responsive Poly(aspartic acid) Nanogels in Inverse Emulsion

“…The volume ratio of polar to apolar phase was 1:1 in each case, and experiments were done in Wassermann tubes with 2 ml sample volumes. As water-in-oil (W/O) emulsions can be stabilized by surfactants with low HLB (hydrophilic-lipophilic balance) number, a widely used surfactant, Span 80 (HLB = 4.3) was chosen [5]. The concentration of the surfactant in the apolar phase varied between 1 and 20 w/V%.…”

“…Besides these macroscopic applications the living cells can be targeted with nanogels (with diameter of few hundred nanometers) [2][3][4] since they have a large capacity for the entrapment of bioactive molecules such as drugs, proteins, carbohydrates or DNA and can be taken up by the cells if proper ligands (e.g. recognition factors) are immobilized onto their surface [5,6]. Well-known approaches for preparing nanogels include photolithographic and micromolding techniques, microfluidics, free radical heterogeneous polymerization in dispersion, nanoprecipitation and emulsion techniques [2,[7][8][9].…”