Silk Fibroin Nanoparticles (SFNs) for nanoencapsulation of bioactive molecules

Kheiria Hcini; Kheiria Hcini

ISSN: 2455-3492

International Journal of Nanomaterials, Nanotechnology and Nanomedicine

Mini Review Open Access Peer-Reviewed

Silk Fibroin Nanoparticles (SFNs) for nanoencapsulation of bioactive molecules

Kheiria Hcini*

Author and article information

Department of Life Sciences, Faculty of Science of Tunis, University of Tunis El Manar, Tunisia

*Corresponding author: Dr. Kheiria Hcini, Biodiversity, Biotechnology and Climate Change Laboratory (LR11ES09), Department of Life Sciences, Faculty of Science of Tunis, University of Tunis El Manar, Tunis 2092,

Faculty of Sciences of Gafsa, University Campus Sidi Ahmed Zarroug, University of Gafsa, Gafsa 2112, Tunisia, E-mail: hcinikheiria@yahoo.fr

doi: 10.17352/2455-3492.000057

Received: 06 February, 2024 | Accepted: 18 March, 2024 | Published: 19 March, 2024

Keywords: Silk fibroin; Nanoparticles; Nanoencapsulation; Bioactive molecules

Cite this as

Hcini K (2024) Silk Fibroin Nanoparticles (SFNs) for nanoencapsulation of bioactive molecules. Int J Nanomater Nanotechnol Nanomed 10(1): 012-015. DOI: 10.17352/2455-3492.000057

Copyright License

© 2024 Hcini K. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Silk Fibroin Nanoparticles (SFNs) have become a reliable and effective biomaterial for nanoencapsulation in several fields such as food, biocosmetics, and medical products due to their physicochemical characteristics. Recently, it has also been developed for application in biomaterials and regenerative medicine, also for cellular nanoencapsulation, and drug delivery systems. Silk fibroin is a natural biomaterial relatively not expensive, biocompatible, eco-friendly, and non-toxic FDA-approved protein derived from the Bombyx mori silkworm cocoon. Fibroin has recently been investigated in the drug field carrier for controlled release. Their application has also become widespread in regenerating therapy as a support for regenerating tissues, as well as in nanomedicine. Furthermore, SFNs have been studied as a carrier for single bioactive molecules such as resveratrol, quercetin, or curcumin for volatile compounds, and for vegetal oils in the form of emulsions. The nanoencapsulation of bioactive compounds in a biopolymer of silk fibroin can be efficiently protected from harmful environmental agents like light, oxygen, or water. The present review reveals that silk fibroin nanoparticles constitute a useful biomaterial to protect, stabilize, and deliver bioactive components. This is a promising combination in safety food, biocosmetic products, nanomedicine, and healthcare.

Main article text

Introduction

Silk Fibroin (SF) extracted from Bombyx mori cocoons has a unique association of physicochemical and biological properties, including nontoxicity, biocompatibility, and biodegradability, making it an outstanding biomaterial for use in a wide range of therapies [1]. This biopolymer, formulated as particles, has important applications in different domains for its ability to protect and deliver a wide range of natural bioactive compounds [2-6]. Silk Fibroin Nanoparticles (SFNs) constitute a highly customizable biomaterial with effective potential in biomedical applications. This biopolymer is used in medicine for its capacity to act as a reversible carrier of bioactive molecules [7-9]. In order to stabilize and protect delicate and precious bioactive compounds, it is beneficial to encapsulate them prior to application. The application of nanoencapsulation is becoming increasingly important in the pharmaceutical, food, cosmetics, textile, personal care, chemical, biotechnology, and medicinal industries due to its potential for stabilization and controlled release under desired conditions of bioactive compounds [5,6,10-12]. Bioactive compounds encapsulated in a silk fibroin biopolymer can be efficiently protected from harmful environmental agents like light, oxygen, or water. Their extensive hydrogen bonding, their hydrophobic nature, and their high degree of crystallinity contribute to the stability of silk biomaterials [13-15]. This mini-review provides an overview of silk fibroin nanoparticles as a biopolymer for nanoencapsulation of biologically active compounds.

Silk Fibroin Nanoparticles (SFNs) as a biomaterial for nanoencapsulation

Various materials have been previously investigated for nanoencapsulation. Proteins are particularly effective encapsulating biopolymers because their physicochemical and biological characteristics (including amphiphilic character, capacity to self-associate and interact with a variety of substances, high molecular weight, and molecular chain flexibility) provide excellent functional properties for encapsulation. Though many biomaterials have been studied for encapsulation in food products, biocosmetic, and medicinal applications, Silk Fibroin (SF) is an especially attractive biopolymer due to its unique chemical and physical properties [2].

Bombyx mori SF is composed of two chains – a heavy chain, approximately 325 kDa, and a light chain, approximately 25 kDa – linked by a single disulfide bridge. The heavy chain of SF is composed of crystalline and amorphous domains. The crystalline domain consists of glycine–alanine repeats interconnected with serine and tyrosine amino acids. The amorphous domain consists of the more bulky amino acids such as aspartic acid. The crystalline domains, which form antiparallel β-sheet secondary structures, are interspersed, by the more flexible amorphous regions. The two chains are bound together by a sericin coating and the removal of this sericin coating, before fibroin processing, removes the thrombogenic and inflammatory responses of SF. This unique structure allows silk to self-assemble into crystallized β-sheets. Their high degree of crystallinity, extensive hydrogen bonding, and their hydrophobic nature contribute to the stability of silk biomaterials [3, 16].

Silk fibroin is a biopolymer extracted from the domesticated silkworm (Bombyx mori) cocoons (Figure 1) that is FDA-approved, edible, non-toxic, biocompatible, biodegradable and relatively not expensive [15,17]. Recently silk fibroin has been investigated as a scaffold for tissue engineering and a drug carrier for controlled release. Owing to its excellent biocompatibility and physicochemical properties, SF constitutes an attractive biomaterial in biomedical and tissue engineering applications [3,6,9,16,18]. Similarly, there are several studies reporting the suitability of SFNs as active vehicles for the transport and release of biomolecules targeting cancer cells or to treat inflammatory conditions such as inflammatory bowel disease and periodontitis [5,19-21]. Furthermore, SFNs have been investigated as an effective encapsulant for single antioxidant molecules such as resveratrol, quercetin, or curcumin for volatile compounds, and for vegetal oils in the form of emulsions [5,6,15]. On account of all of these properties, silk fibroin has become a promising tool for nanoencapsulation of bioactive molecules.

Nanoencapsulation is a process of encapsulating a material containing an active ingredient by a protective coating layer, or embedded within an encapsulating matrix or membrane, providing a physical barrier between the incorporated compound and the surrounding environment. This technique protects sensitive and precious molecules from deterioration by shielding them from harmful environmental conditions. The barrier that the encapsulating material provides can also delay the evaporation of volatile compounds particularly if the compound interacts with the encapsulant material. In addition to stabilizing and protecting encapsulated flavors, fragrances, oils, and phenolic compounds, nanoencapsulation may also be able to provide controlled release under specific conditions [3,6,22]. Quercetin loaded into the Silk Fibroin Nanoparticles (QSFNs) conserved the antioxidant activity in comparison with the equivalent amount of free Quercetin. QSFNs provide the capacity to protect the drug from degradation in the adverse gastrointestinal tract environment, enabling its easy transport and internalization through the intestinal epithelial cells or colon, and thus improving its pharmacokinetics and bioavailability after oral administration and making them an excellent platform for the future development of nanotherapies (Figure 2) [5,23,24].

The loaded nanoparticles with rosemary polyphenolic compounds were characterized in terms of morphology, size, polydispersity, Z-potential, secondary structure of the protein, encapsulation efficiency, loading content, and antioxidant activity (Figure 3). The encapsulated polyphenols retained nearly 85% of the radical scavenging activity against DPPH after 24 h. of incubation at 37 °C. The results showed that silk fibroin nanoparticles loaded with rosemary post-distilled extracts are thus a promising combination for several applications in food technology or nanomedicine. In reference to the loading polyphenol content determinations, diterpene fraction along with the phenolic acids, salvianic and rosmarinic acids were retained as major components in the SFNs, although a deeper study should be developed [12].

Furthermore, polyphenolic compounds such as curcumin, quercetin, and resveratrol are known to exhibit anti-inflammatory effects in several cell types [25-28]. Previous works proved the utility of SFNs as drug carriers due to their optimal physicochemical properties and biosafety. For instance, several studies have described that SFN enhances polyphenol bioavailability with a low cytotoxic effect, highlighting their potential use as therapeutics in different diseases such as cancer or inflammatory diseases [5,9,15,20,29,30].

Nanoencapsulation has a number of interesting advantages in different domains due to its potential for stabilization and delivery of delicate and precious bioactive molecules. Thus, bioactive compounds encapsulated in a biopolymer can be efficiently protected from harmful environmental agents like light, oxygen, or water [9,12]. In Nanomedicine, advances in targeted drug delivery systems using nanoparticles improve the precision and effectiveness of cancer treatments and the development of nanoscale imaging agents for earlier and more accurate disease diagnosis [31].

Conclusion

Silk Fibroin Nanoparticles (SFNs) represent an effective biopolymer for nanoencapsulation of bioactive molecules in safety-food, biocosmetic, and soft medecine due to their physicochemical characteristics. Biologically active molecules encapsulated in this biomaterial can be efficiently protected from chemical and physical damage. Recently, SFNs have also been developed for application in biomaterials and regenerative medicine, also for cellular nanoencapsulation, and controlled drug delivery systems. Thus, nanoencapsulation is one of the techniques used to raise the protection of bioactive compounds and to be improved under controlled release. This technique may be defined as a method by which one or more bioactive natural products are released under specific conditions. This controlled release could be used to maximize the effectiveness and reliability of delicate and valuable bioactive compounds.

Acknowledgement

The author thanks the “Ministry of Higher Education, Scientific Research and Technology, Tunisia”, for supporting this study. She also extends their appreciation to the Instituto Murciano de Investigación y Desarrollo Agrario y Medioambiental (IMIDA), La Alberca, 30150 Murcia, Spain.