Glycogen as a Building Block for Advanced Biological Materials

Abstract

complex drug delivery systems that are challenging to scale up and therefore have limited clinical and commercial translation. Although numerous nanoparticles have been widely developed and used for various applications, including biomedical applications, [2] there is a growing interest in nontoxic and degradable alternatives to first-generation synthetic nanomaterials. Ideally the synthesis of such nanoparticles needs to be cost effective, simple, green, reproducible, scalable, and the constitutive building blocks of the nanoparticles should be nontoxic, functional, biodegradable, and available on a large scale. Naturally occurring nanoparticles could be such a valid alternative. These nanoparticles include intracellular structures, such as magnetosomes [3] and glycogen, and extracellular assemblies such as lipoproteins and viruses. [3] Among these, glycogen is the most abundant and versatile biological nanoparticle, which fulfils the requirements for the fabrication of nanostructured biomaterials. Glycogen is nature's prime nanoparticle that exists in most organisms, from bacteria and archaea to humans, [4,5] as a vital component of the cellular energy machinery. It is a highly branched polysaccharide comprising repeating units of glucose connected by linear α-d-(1,4) glycosidic linkages with α-d-(1,6) branching, structured into roughly spherical nanoparticles that have a high water solubility and molecular weight.The use of polysaccharides as components for advanced materials has been an attractive concept for decades. [6,7] A key motive is that polysaccharides, as a natural biomaterial, are endowed with a level of biodegradability and biocompatibility. In addition, they can be easily modified chemically or biochemically to produce functional derivatives, which are important for various therapeutic applications. [8] The structures of polysaccharides vary considerably but span from linear to highly branched polymers with molecular weights ranging from thousands to millions, composed of mono-or disaccharides, or short-chain oligomers bound together by glycosidic linkages. [9] There is a rich history of research on the use of polysaccharides in a range of therapeutic applications including: i) soft tissue engineering, [10,11] where the materials can be designed to mimic the mechanical properties of the extracellular matrix in the tissue; ii) as drug, protein, or gene delivery systems, [7,12,13] where polysaccharides have a large number of reactive groups [14] that allow for tunable properties [12] such as pH-responsiveness; [15] and iii) as nanoprobes for cellular Biological nanoparticles found in living systems possess distinct molecular architectures and diverse functions. Glycogen is a unique biological polysaccharide nanoparticle fabricated by nature through a bottom-up approach. The biocatalytic synthesis of glycogen has evolved over time to form a nanometer-sized dendrimer-like structure (20-150 nm) with a highly branched surface and a dense core. This makes glycogen markedly different from other natur...

Ultrasound-Assisted Microencapsulation of Soybean Oil and Vitamin D Using Bare Glycogen Nanoparticles

“…Depending on the source, the molecular weight, size and structural properties of glycogen nanoparticles vary. The nanoparticle size spans from approximately 20 to 90 nm with molecular weights ranging from the 0.4 × 10 6 to 18 × 10 6 Da [ 24 ]. A slightly negatively charged surface, due to the residual phosphate groups from the biological synthesis, and a small number of bound proteins were observed on glycogen nanoparticles ( Figure 1 , Table 1 ).…”

“…Depending on the source, the molecular weight, size and structural properties of glycogens can vary, as summarized in Table 1 . Glycogen has several advantageous properties, such as biocompatibility, biodegradability, high water solubility and hydroxyl functional groups, that make it well suited for use as a functional nanomaterial [ 24 ]. For instance, RNA and DNA delivery systems were engineered using bovine liver, oyster glycogen and phytoglycogen.…”

“…These capsules were glucose responsive and tend to release the encapsulated insulin after incubation with glucose. a Data taken from Besford et al [24]. b Data taken from Besford et al [32].…”

“…To the best of our knowledge, microcapsules made solely of unmodified/bare bovine liver, rabbit liver and oyster glycogen/phytoglycogen have not been reported. In this a Data taken from Besford et al [24]. b Data taken from Besford et al [32].…”

Advancing the stimuli response of polymer-based drug delivery systems for ocular disease treatment

“…3,4 Polymeric materials have been used as the main component in various DDSs, possibly due to their excellent properties, which include high water absorption capability, structural stability in aqueous media, excellent biocompatibility, and resemblance to living tissues. [5][6][7] Generally, the encapsulation of drug molecules by polymeric carriers is controlled by van der Waals interactions, hydrogen bonds, π-π conjugations, electrostatic forces, or chemical linkages. However, an accurate mechanism has not been completely elucidated, and this means that empirical results are utilized to demonstrate the loading of drug molecules into polymeric carriers.…”