Effect of Chain-End Chemistries on the Efficiency of Coupling Antibodies to Polymers Using Unnatural Amino Acids.

Novel conjugates that incorporate strategies for increasing the therapeutic payload, such as targeted polymeric delivery vehicles, have great potential in overcoming limitations of conventional antibody therapies that often exhibit immunogenicity and limited drug loading. Click chemistry has significantly expanded the toolbox of effective strategies for developing hybrid polymer-biomolecule conjugates, however, effective systems require orthogonality between the polymer and biomolecule chemistries to achieve efficient coupling. Here, three cycloaddition-based strategies for antibody conjugation to polymeric carriers are explored and show that a purely radical-based method for polymer synthesis and subsequent biomolecule attachment has a trade-off between coupling efficiency of the antibody and the ability to synthesize polymers with controlled chemical properties.

Understanding the Uptake of Nanomedicines at Different Stages of Brain Cancer Using a Modular Nanocarrier Platform and Precision Bispecific Antibodies.

Increasing accumulation and retention of nanomedicines within tumor tissue is a significant challenge, particularly in the case of brain tumors where access to the tumor through the vasculature is restricted by the blood-brain barrier (BBB). This makes the application of nanomedicines in neuro-oncology often considered unfeasible, with efficacy limited to regions of significant disease progression and compromised BBB. However, little is understood about how the evolving tumor-brain physiology during disease progression affects the permeability and retention of designer nanomedicines.

Targeted and modular architectural polymers employing bioorthogonal chemistry for quantitative therapeutic delivery.

There remain several key challenges to existing therapeutic systems for cancer therapy, such as quantitatively determining the true, tissue-specific drug release profile , as well as reducing side-effects for an increased standard of care. Hence, it is crucial to engineer new materials that allow for a better understanding of the pharmacokinetic/pharmacodynamic behaviours of therapeutics. We have expanded on recent "click-to-release" bioorthogonal pro-drug activation of antibody-drug conjugates (ADCs) to develop a modular and controlled theranostic system for quantitatively assessing site-specific drug activation and deposition from a nanocarrier molecule, by employing defined chemistries.

EphA3 Pay-Loaded Antibody Therapeutics for the Treatment of Glioblastoma.

The EphA3 receptor has recently emerged as a functional tumour-specific therapeutic target in glioblastoma (GBM). EphA3 is significantly elevated in recurrent disease, is most highly expressed on glioma stem cells (GSCs), and has a functional role in maintaining self-renewal and tumourigenesis. An unlabelled EphA3-targeting therapeutic antibody is currently under clinical assessment in recurrent GBM patients.

Effects of Surface Charge of Hyperbranched Polymers on Cytotoxicity, Dynamic Cellular Uptake and Localization, Hemotoxicity, and Pharmacokinetics in Mice.

Nanoscaled polymeric materials are increasingly being investigated as pharmaceutical products, drug/gene delivery vectors, or health-monitoring devices. Surface charge is one of the dominant parameters that regulates nanomaterial behavior in vivo. In this paper, we demonstrated how control over chemical synthesis allowed manipulation of nanoparticle surface charge, which in turn greatly influenced the in vivo behavior.

Using Peptide Aptamer Targeted Polymers as a Model Nanomedicine for Investigating Drug Distribution in Cancer Nanotheranostics.

Theranostics is a strategy that combines multiple functions such as targeting, stimulus-responsive drug release, and diagnostic imaging into a single platform, often with the aim of developing personalized medicine.1,2 Based on this concept, several well-established hyperbranched polymeric theranostic nanoparticles were synthesized and characterized as model nanomedicines to investigate how their properties affect the distribution of loaded drugs at both the cell and whole animal levels. An 8-mer peptide aptamer was covalently bound to the periphery of the nanoparticles to achieve both targeting and potential chemosensitization functionality against heat shock protein 70 (Hsp70).

Localised delivery of doxorubicin to prostate cancer cells through a PSMA-targeted hyperbranched polymer theranostic.

The therapeutic potential of hyperbranched polymers targeted to prostate cancer and loaded with doxorubicin was investigated. Polyethylene glycol hyperbranched polymers were synthesised via RAFT polymerisation to feature glutamate urea targeting ligands for PSMA on the periphery. The chemotherapeutic, doxorubicin, was attached to the hyperbranched polymers through hydrazone formation, which allowed controlled release of the drug from the polymers in vitro endosomal conditions, with 90% release of the drug over 36 h.

Stability of Trithiocarbonate RAFT Agents Containing Both a Cyano and a Carboxylic Acid Functional Group.

The hydrolytic degradation of widely used cyano-containing, acid-bearing trithiocarbonate reversible addition-fragmentation chain-transfer (RAFT) agents has been identified and shown to effect the RAFT polymerization and end-group fidelity of PMMA polymers. The hydrolysis occurred when the RAFT agents were stored under the recommended conditions. Degradation was identified in both commercially available and popular synthetic RAFT agents.

Overcoming Instability of Antibody-Nanomaterial Conjugates: Next Generation Targeted Nanomedicines Using Bispecific Antibodies.

Targeted nanomaterials promise improved therapeutic efficacy, however their application in nanomedicine is limited due to complexities associated with protein conjugations to synthetic nanocarriers. A facile method to generate actively targeted nanomaterials is developed and exemplified using polyethylene glycol (PEG)-functional nanostructures coupled to a bispecific antibody (BsAb) with dual specificity for methoxy PEG (mPEG) epitopes and cancer targets such as epidermal growth factor receptor (EGFR). The EGFR-mPEG BsAb binds with high affinity to recombinant EGFR (KD : 1 × 10(-9) m) and hyperbranched polymer (HBP) consisting of mPEG (KD : 10 × 10(-9) m) and demonstrates higher avidity for HBP compared to linear mPEG.

Targeting Nanomedicines to Prostate Cancer: Evaluation of Specificity of Ligands to Two Different Receptors In Vivo.

Purpose: This manuscript utilised in vivo multispectral imaging to demonstrate the efficacy of two different nanomedicine formulations for targeting prostate cancer.

Methods: Pegylated hyperbranched polymers were labelled with fluorescent markers and targeting ligands against two different prostate cancer markers; prostate specific membrane antigen (PSMA) and the protein kinase, EphrinA2 receptor (EphA2). The PSMA targeted nanomedicine utilised a small molecule glutamate urea inhibitor of the protein, while the EphA2 targeted nanomedicine was conjugated to a single-chain variable fragment based on the antibody 4B3 that has shown high affinity to the receptor.

Evaluation of Polymeric Nanomedicines Targeted to PSMA: Effect of Ligand on Targeting Efficiency.

Targeted nanomedicines offer a strategy for greatly enhancing accumulation of a therapeutic within a specific tissue in animals. In this study, we report on the comparative targeting efficiency toward prostate-specific membrane antigen (PSMA) of a number of different ligands that are covalently attached by the same chemistry to a polymeric nanocarrier. The targeting ligands included a small molecule (glutamate urea), a peptide ligand, and a monoclonal antibody (J591).

The in vivo fate of nanoparticles and nanoparticle-loaded microcapsules after oral administration in mice: Evaluation of their potential for colon-specific delivery.

Anti-cancer drug loaded-nanoparticles (NPs) or encapsulation of NPs in colon-targeted delivery systems shows potential for increasing the local drug concentration in the colon leading to improved treatment of colorectal cancer. To investigate the potential of the NP-based strategies for colon-specific delivery, two formulations, free Eudragit® NPs and enteric-coated NP-loaded chitosan-hypromellose microcapsules (MCs) were fluorescently-labelled and their tissue distribution in mice after oral administration was monitored by multispectral small animal imaging. The free NPs showed a shorter transit time throughout the mouse digestive tract than the MCs, with extensive excretion of NPs in faeces at 5h.

Reversible activation of pH-sensitive cell penetrating peptides attached to gold surfaces.

pH-sensitive viral fusion protein mimics are widely touted as a promising route towards site-specific delivery of therapeutic compounds across lipid membranes. Here, we demonstrate that a fusion protein mimic, designed to achieve a reversible, pH-driven helix-coil transition mechanism, retains its functionality when covalently bound to a surface.

Bioinspired phosphorylcholine containing polymer films with silver nanoparticles combining antifouling and antibacterial properties.

The antibacterial (bioactive) and antifouling (biopassive) properties of stable, uniform, high surface coverage films of poly(hydroxyethyl methacrylate-co-2-methacryloyloxyethyl phosphorylcholine) (p(HEMA-co-MPC)) with embedded, non-leaching silver nanoparticles (AgNPs) are reported. Based on the experimental findings, a mechanism of action of AgNPs in antibacterial activity in combination with antifouling characteristics is discussed. Long-term antifouling studies of E.

Enzyme cleavable nanoparticles from peptide based triblock copolymers.

A solid-phase synthesis based approach towards protease cleavable polystyrene-peptide-polystyrene triblock copolymers and their formulation to nanoparticulate systems is presented. These nanoparticles are suitable for the optical detection of an enzyme and have the potential for application as a drug delivery system. Two different peptide sequences, one cleaved by trypsin (GFF), the other by hepsin (RQLRVVGG), a protease overexpressed in early stages of prostate cancer, are used as the central part of the triblock.

Biomimetic silver-containing colloids of poly(2-methacryloyloxyethyl phosphorylcholine) and their film-formation properties.

The synthesis of stable dispersions of hybrid colloids comprising copolymers of biocompatible 2-hydroxyethyl methacrylate (HEMA) and zwitterionic, biomimetic 2-methacryloyloxyethyl phosphorylcholine (MPC) incorporating antibacterial AgBF(4) by inverse miniemulsion is described. The prepared hybrid colloids were designed to provide both antibacterial and antifouling properties for the formation of interesting, multifunctional films. The obtained particles had sizes in the range of 130-160 nm with two different weight ratios of MPC to HEMA (1:10 and 2:5) and AgBF(4) contents between 0% and 15%.

Two-dimensional crystal growth and stacking of bis(phthalocyaninato) rare earth sandwich complexes at the 1-phenyloctane/graphite interface.

Initial stages of two-dimensional crystal growth of the double-decker sandwich complex Lu(Pc*)2 [Pc* = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] have been studied by scanning tunneling microscopy at the liquid/solid interface between 1-phenyloctane and highly oriented pyrolytic graphite. High-resolution images strongly suggest alignment of the double-decker molecules into monolayers with the phthalocyanine rings parallel to the surface. Domains were observed with either hexagonal or quadrate packing motifs, and the growing interface of the layer was imaged.