Polymersomes are robust, versatile nanostructures that can be tailored by varying the chemical structure of copolymeric building blocks, giving control over their size, shape, surface chemistry, and membrane permeability. In particular, the generation of nonspherical nanostructures has attracted much attention recently, as it has been demonstrated that shape affects function in a biomedical context. Until now, nonspherical polymersomes have only been constructed from nondegradable building blocks, hampering a detailed investigation of shape effects in nanomedicine for this category of nanostructures. Herein, we demonstrate the spontaneous elongation of spherical polymersomes comprising the biodegradable copolymer poly(ethylene glycol)-b-poly(d,l-lactide) into well-defined nanotubes. The size of these tubes is osmotically controlled using dialysis, which makes them very easy to prepare. To confirm their utility for biomedical applications, we have demonstrated that, alongside drug loading, functional proteins can be tethered to the surface utilizing bio-orthogonal “click” chemistry. In this way the present findings establish a novel platform for the creation of biocompatible, high-aspect ratio nanoparticles for biomedical research.

A new strategy is described for the modification of CCMV for loading of cargoes inside the viral capsid. Sortase A, an enzyme which is present in Gram-positive bacteria, was used to attach cargo to the glycine-tagged N-termini of several CCMV variants. We show that small molecules and proteins bearing a C-terminal LPETG-motif can be attached in this way. This method allows for the site-specific, covalent, and orthogonal modification of CCMV capsids in a mild fashion, leading to high encapsulation efficiencies. This strategy can easily be expanded to other types of cargoes, labeled with an LPETG-tag without altering protein function.

Recombinant llama heavy-chain antibody fragments (VHHs) are promising tools in the field of targeted nanomedicine. 7D12, a VHH against the epidermal growth factor receptor (EGFR) that is overexpressed in various cancers, has been evaluated as an effective cancer-targeting VHH in multiple studies. The small size of VHHs (15–20 kDa) results in a low circulation half-life, which can be disadvantageous for certain applications. A solution to this problem is to attach VHHs to the surface of nanoparticles to increase the hydrodynamic radius of the conjugate. This approach simultaneously allows the incorporation of different VHHs and other targeting moieties and therapeutic components into one structure, creating multispecificity and versatility for therapy and diagnosis. Here, we present the construction of highly defined 7D12-containing nanoparticles by utilizing thermoresponsive diblock elastin-like peptides that reversibly self-assemble into micellar structures. The resulting particles have a hydrodynamic radius of 24.3 ± 0.9 nm and retain full EGFR-binding capacity. We present proof of concept of the usability of such particles by controlled incorporation of a photosensitizer and show that the resulting nanoparticles induce EGFR-specific light-induced cell killing. This approach is easily extended to the controlled incorporation of various functional modules, improving therapy and diagnosis with targeted nanomedicine.

Here we develop a novel approach allowing the noncovalent assembly of proteins on well-defined nanoscaffolds such as virus particles. The antibody-binding peptide Z33 was genetically fused to the monomeric yellow fluorescent protein and 4-coumarate:CoA-ligase 2. This Z33 "tag" allowed their patterning on the surface of zucchini yellow mosaic virus by means of specific antibodies directed against the coat protein of the virus. The approach was validated by affinity assays and correlative microscopy. The coverage efficiency was ≈ 87%. Fluorescence and enzymatic activity were fully retained after assembly. The principle of using the combination of a scaffold-specific antibody and Z33-fusion proteins can be extended to a wide variety of proteins/enzymes and antigenic scaffolds to support coupling for creating functional "biochips" with optical or catalytic properties.