Layer‐By‐Layer‐Assembled Capsules and Films for Therapeutic Delivery

Abstract

Polymeric materials formed via layer-by-layer (LbL) assembly have promise for use as drug delivery vehicles. These multilayered materials, both as capsules and thin fi lms, can encapsulate a high payload of toxic or sensitive drugs, and can be readily engineered and functionalized with specific properties. This review highlights important and recent studies that advance the use of LbL-assembled materials as therapeutic devices. It also seeks to identify areas that require additional investigation for future development of the field. A variety of drug-loading methods and delivery routes are discussed. The biological barriers to successful delivery are identified, and possible solutions to these problems are discussed. Finally, state-of-the-art degradation and cargo release mechanisms are also presented.

Design Advances in Particulate Systems for Biomedical Applications

“…[ 165 ] Besides electrostatic forces, other kinds of interactions can be used. [ 166 ] The core may remain solid or be liquefi ed (acting as a sacrifi cial template) after the deposition of the layers.…”

“…Three main strategies are currently used to encapsulate drugs in those kinds of systems: (I) using the bioactive agents as a constituent of the multilayers (e.g., proteins or nucleic acids which exhibit pH-dependent charges); (II) preloading the core template and (III) post-loading by modifying the permeability of the multilayered structure - Figure 17 . Low encapsulation effi ciency is the main limitation of LbL particles, [ 165 ] while their main advantage is a great fl exibility that enables a successful internalization by the cells.…”

Interfacial assembly of dendritic microcapsules with host–guest chemistry

“…In addition to self-assembled vesicles [14][15][16][17][18] or synthetic polymersomes 19 , the majority of reported structures rely on templating by exo [20][21][22] , meso 23,24 , endo 25 or exo-endo 26,27 methods. These approaches are experimentally laborious, with the use of a solid template requiring subsequent etching under relatively harsh conditions to obtain a hollow structure, lowering encapsulation and loading efficiencies.…”

Tailoring Substrate Hydrophilicity Using Grafted Polypeptide Nanocoatings

“…In comparison, the layer-by-layer (LbL) approach has been utilized to immobilize enzymes, proteins, and synthetic polypeptides with various functionalities and hydrophobicities. [12,[15][16][17][18][19] Despite the fine control over film properties, the LbL technique involves multistep processing and relies on the availability of complementary functionalized polypeptides. In general, the formation of peptide-based films via the LbL approach relies on electrostatic interactions between two oppositely charged peptides.…”

“…In general, the formation of peptide-based films via the LbL approach relies on electrostatic interactions between two oppositely charged peptides. [15,19] Therefore, the incorporation of non-ionic hydrophobic peptide segments into LbL-generated films remains challenging. Furthermore, hydrophobic peptides are typically insoluble in most solvents, which hampers their use as building blocks for films and coatings.…”