Versatile design of amphiphilic glycopolypeptides nanoparticles for lectin recognition

Polypeptide-Based Systems: From Synthesis to Application in Drug Delivery

Synthetic polypeptides are biocompatible and biodegradable macromolecules whose composition and architecture can vary over a wide range. Their unique ability to form secondary structures, as well as different pathways of modification and biofunctionalization due to the diversity of amino acids, provide variation in the physicochemical and biological properties of polypeptide-containing materials. In this review article, we summarize the advances in the synthesis of polypeptides and their copolymers and the application of these systems for drug delivery in the form of (nano)particles or hydrogels. The issues, such as the diversity of polypeptide-containing (nano)particle types, the methods for their preparation and drug loading, as well as the influence of physicochemical characteristics on stability, degradability, cellular uptake, cytotoxicity, hemolysis, and immunogenicity of polypeptide-containing nanoparticles and their drug formulations, are comprehensively discussed. Finally, recent advances in the development of certain drug nanoformulations for peptides, proteins, gene delivery, cancer therapy, and antimicrobial and anti-inflammatory systems are summarized.

Nanostructured multifunctional stimuli-responsive glycopolypeptide-based copolymers for biomedical applications

Inspired by natural resources, such as peptides and carbohydrates, glycopolypeptide biopolymer has recently emerged as a new form of biopolymer being recruited in various biomedical applications. Glycopolypeptides with well-defined secondary structures and pendant glycosides on the polypeptide backbone have sparked lots of research interest and they have an innate ability to self-assemble in diverse structures. The nanostructures of glycopolypeptides have also opened up new perspectives in biomedical applications due to their stable three-dimensional structures, high drug loading efficiency, excellent biocompatibility, and biodegradability. Although the development of glycopolypeptide-based nanocarriers is well-studied, their clinical translation is still limited. The present review highlights the preparation and characterization strategies related to glycopolypeptides-based copolymers, followed by a comprehensive discussion on their biomedical applications with a specific focus on drug delivery by various stimuli-responsive (e.g., pH, redox, conduction, and sugar) nanostructures, as well as their beneficial usage in diagnosis and regenerative medicine.

Amphiphilic Polypeptides Obtained by the Post-Polymerization Modification of Poly(Glutamic Acid) and Their Evaluation as Delivery Systems for Hydrophobic Drugs

Synthetic poly(amino acids) are a unique class of macromolecules imitating natural polypeptides and are widely considered as carriers for drug and gene delivery. In this work, we synthesized, characterized and studied the properties of amphiphilic copolymers obtained by the post-polymerization modification of poly(α,L-glutamic acid) with various hydrophobic and basic L-amino acids and D-glucosamine. The resulting glycopolypeptides were capable of forming nanoparticles that exhibited reduced macrophage uptake and were non-toxic to human lung epithelial cells (BEAS-2B). Moreover, the developed nanoparticles were suitable for loading hydrophobic cargo. In particular, paclitaxel nanoformulations had a size of 170-330 nm and demonstrated a high cytostatic efficacy against human lung adenocarcinoma (A549). In general, the obtained nanoparticles were comparable in terms of their characteristics and properties to those based on amphiphilic (glyco)polypeptides obtained by copolymerization methods.

Functional Glycopolypeptides: Synthesis and Biomedical Applications

Employing natural-based renewable sugar and saccharide resources to construct functional biopolymer mimics is a promising research frontier for green chemistry and sustainable biotechnology. As the mimics/analogues of natural glycoproteins, synthetic glycopolypeptides attracted great attention in the field of biomaterials and nanobiotechnology. This review describes the synthetic strategies and methods of glycopolypeptides and their analogues, the functional self-assemblies of the synthesized glycopolypeptides, and their biological applications such as biomolecular recognition, drug/gene delivery, and cell adhesion and targeting, as well as cell culture and tissue engineering. Future outlook of the synthetic glycopolypeptides was also discussed.

Chemo-enzymatic synthesis of glycolipids, their polymerization and self-assembly

This paper describes the synthesis of bio-based methacrylated 12-hydroxystearate glucose (MASG), and its (co)polymerization with methyl methacrylate (MMA) by either free- or RAFT radical polymerizations.

Polydimethylsiloxane-Based Giant Glycosylated Polymersomes with Tunable Bacterial Affinity

A synthetic cell mimic in the form of giant glycosylated polymersomes (GGPs) comprised of a novel amphiphilic diblock copolymer is reported. A synthetic approach involving a poly(dimethylsiloxane) (PDMS) macro-chain transfer agent (macroCTA) and postpolymerization modification was used to marry the hydrophobic and highly flexible properties of PDMS with the biological activity of glycopolymers. 2-Bromoethyl acrylate (BEA) was first polymerized using a PDMS macroCTA ( M_n,th ≈ 4900 g·mol^-1, Đ = 1.1) to prepare well-defined PDMS- b-pBEA diblock copolymers ( Đ = 1.1) that were then substituted with 1-thio-β-d-glucose or 1-thio-β-d-galactose under facile conditions to yield PDMS- b-glycopolymers. Compositions possessing ≈25% of the glycopolymer block (by mass) were able to adopt a vesicular morphology in aqueous solution (≈210 nm in diameter), as indicated by TEM and light scattering techniques. The resulting carbohydrate-decorated polymersomes exhibited selective binding with the lectin concanavalin A (Con A), as demonstrated by turbidimetric experiments. Self-assembly of the same diblock copolymer compositions using an electroformation method yielded GGPs (ranging from 2-20 μm in diameter). Interaction of these cell-sized polymersomes with fimH positive E. coli was then studied via confocal microscopy. The glucose-decorated GGPs were found to cluster upon addition of the bacteria, while galactose-decorated GGPs could successfully interact with (and possibly immobilize) the bacteria without the onset of clustering. This demonstrates an opportunity to modulate the response of these synthetic cell mimics (protocells) toward biological entities through exploitation of selective ligand-receptor interactions, which may be readily tuned through a considered choice of carbohydrate functionality.

Reduction sensitive hyaluronan-SS-poly(ε-caprolactone) block copolymers as theranostic nanocarriers for tumor diagnosis and treatment

Tumor-targeted multifunctional nanocarriers play an important role in tumor diagnosis and treatment. Herein, disulfide bonds linked amphiphilic hyaluronan-SS-poly(ε-caprolactone) diblock copolymers (HA-SS-PCL) were synthesized and studied as theranostic nanocarriers for tumor diagnosis and treatment. The chemical structure of HA-SS-PCL was confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H NMR). The self-assembling behavior of the HA-SS-PCL into GSH-responsive micelles and their degradation were characterized by fluorescence spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). Theranostic nanocarriers encapsulating doxorubicin (DOX) and superparamagnetic iron oxide (SPIO) were formed via a dialysis. In vitro drug release results suggested that the HA-SS-PCL micelles possessed reductant-triggered doxorubicin release ability, which was confirmed by 100% of DOX release from HA-SS-PCL micelles within 12 h under 10 mM of glutathione (GSH), whereas about 40% of DOX was released under non-reductive condition within 24 h. Both flow cytometry and confocal laser scanning microscopy (CLSM) analysis revealed that the HA-SS-PCL micelles loaded with DOX were internalized in HepG2 cell via a receptor mediated mechanism between hyaluronan and the CD44 receptor. Furthermore, the MTT assay and cell apoptosis analysis revealed that the DOX-loaded HA-SS-PCL micelles exhibited pronounced antitumor ability towards HepG2 cells compared with that of the reduction-insensitive HA-PCL micelles at the same DOX dosage. The r₂ relaxivity value of the DOX/SPIO loaded HA-SS-PCL micelles was up to 221.2 mM^-1 s^-1 (Fe). Thus, the obtained HA-SS-PCL block copolymers demonstrate promising potential as tumor targeting theranostic nanocarriers in the field of tumor diagnosis and treatment.

The effect of linker length on ConA and DC-SIGN binding of S-glucosyl functionalized poly(2-oxazoline)s

A series of poly(2-oxazoline) based glycopolymers with different linkers were prepared via thiol–ene click reaction and cationic ring opening reaction. The binding of these polymers to lectins were studied.

Bioreducible amphiphilic block copolymers based on PCL and glycopolypeptide as multifunctional theranostic nanocarriers for drug delivery and MR imaging

Amphiphilic diblock poly(ε-caprolactone)-b-glycopolypeptides (PCL–SS–GPPs) bearing disulfide bonds were synthesized from a clickable poly(ε-caprolactone)–SS–poly(2-azidoethyl-l-glutamate) diblock copolymer.

Synthetic polypeptides: from polymer design to supramolecular assembly and biomedical application

This review highlights the recent advances in the chemical design, supramolecular assembly, and biomedical application of synthetic polypeptides fromN-carboxyanhydrides.