Abstract: The present disclosure provides layer-by-layer compositions comprising a plurality of polymer bilayers. Each bilayer comprises a poly(N-vinylpyrrolidone) hydrogen-bonded a polyphenol (tannic acid) layer. In the compositions, at least one poly(N-vinylpyrrolidone) has conjugated thereon a plurality of manganoporphyrin moieties. The layer-by-layer compositions can be deposited on the cell aggregate surface or deposited on an underlying surface such as that of a silica core which, when removed creates a capsule having a hollow space for the addition of such as a therapeutic agent.

Abstract: The theranostic biocompatible microcapsules provided are efficient contrast enhanced imaging agents that combine Magnetic Resonance Imaging (MRI) with ultrasound-triggered drug release for real-time tracking and targeted delivery in vivo. The capsules are assembled via layer-by-layer deposition of the natural polyphenol tannic acid and poly(N-vinylpyrrolidone) with iron oxide nanoparticles incorporated in the capsule wall. The nanoparticle-modified capsules exhibit enhanced T1 and T2 MRI contrast in a clinical MRI scanner. Loaded with the an anticancer drug such as doxorubicin the capsules circulate in the blood stream for at least 48 hours, an improvement compared to non-encapsulated nanoparticles. High-intensity focused ultrasound results in targeted drug release with a 16-fold increase in the pharmacologically active agent localization in tumors compared to off-target organs.

Abstract: The present disclosure provides multifunctional cytoprotective materials applied to coat living cells or aggregates of cells such as, but not limited to, pancreatic islets. The coating utilizes hydrogen-bonded interactions of a natural polyphenol (tannic acid) with poly(N-vinylpyrrolidone) deposited on the cell aggregate surface via non-ionic layer-by-layer assembly. The coating is conformal over the surface of such as mammalian islets. The coated islets maintain their viability and cell functionality for at least 96 hours in vitro. The coating demonstrates immunomodulatory cytoprotective properties suppressing pro-inflammatory cytokine synthesis in stimulated bone marrow-derived macrophages and diabetogenic BDC-2.5 T cells. The coating material combines high chemical stability under physiologically relevant conditions with capability of suppressing cytokine synthesis, crucial parameters for prolonged islet integrity, viability, and function in vivo.

Abstract: Micro-, and nano-scale capsules comprising neutral (uncharged) polymeric layers, layers associated by hydrogen bonding and methods for making such capsules. The capsules of the invention are layered upon a core particle using a layer-by layer-technique. The capsule walls of the capsules of the invention give a tailored response to external stimuli.