Selective functionalization of the external surface of porous nanoparticles is of great interest for numerous potential applications in the field of nanotechnology. Regarding metal–organic frameworks (MOFs), few methods for such modifications have been reported in the literature. Herein, we focus on the covalent attachment of functional polymers on the external surface of MIL-100­(Fe) nanoparticles in order to implement properties such as increased chemical and colloidal stability or dye-labeling for the investigation of the particles by fluorescence based techniques. We prove covalent nanoparticles-polymer bond formation by liquid NMR after dissolution of the functionalized MOF under mild conditions and estimate the amount of covalently attached polymer by UV–vis spectroscopy. The functionalization of the MOF nanoparticles with fluorescently labeled polymers enables the investigation of nanoparticle uptake into tumor cells by fluorescence microscopy. Furthermore, the influence of the polymer shell on the magnetic resonance imaging activity of MIL-100­(Fe) is investigated in detail. The functionalization approach presented here is expected to enable the fabrication of hybrid nanomaterials, extending the enormous chemical space of MOFs into polymer materials.

We report the synthesis of MOF@lipid nanoparticles as a versatile and powerful novel class of nanocarriers based on metal-organic frameworks (MOFs). We show that the MOF@lipid system can effectively store dye molecules inside the porous scaffold of the MOF while the lipid bilayer prevents their premature release. Efficient uptake of the MOF@lipid nanoparticles by cancer cells makes these nanocarriers promising for drug delivery and diagnostic purposes.

Self-assembly of individual units into multicomponent complexes is a powerful approach for the generation of functional superstructures. We present the coordinative interaction of oligohistidine-tags (His-tags) with metal-organic framework nanoparticles (MOF NPs). By this novel concept, different molecular units can be anchored on the outer surface of MOF NPs in a self-assembly process generating multifunctional nanosystems. The article focuses on two main objectives: first, the detailed investigation of the assembly process and fundamental establishment of the novel functionalization concept; and second, its subsequent use for the development of biomacromolecule (e.g., peptides and proteins) delivery vehicles. Three exemplary MOF structures, MIL-88A, HKUST-1, and Zr-fum, based on different metal components, were selected for the external binding of various His-tagged synthetic peptides and recombinant or chemically H-modified proteins. Evidence for simultaneous assembly of different functional units with Zr-fum MOF NPs as well as their successful transport into living cells illustrate the promising potential of the self-assembly approach for the generation of multifunctional NPs and future biological applications. Taking the high number of possible MOF NPs and different functional units into account, the reported functionalization approach opens great flexibility for the targeted synthesis of multifunctional NPs for specific purposes.

Creating a synthetic exoskeleton from abiotic materials to protect delicate mammalian cells and impart them with new functionalities could revolutionize fields like cell-based sensing and create diverse new cellular phenotypes. Herein, we introduce the concept of 'SupraCells', which are living mammalian cells encapsulated and protected within functional modular nanoparticle-based exoskeletons. Exoskeletons are generated within seconds through immediate interparticle and cell/particle complexation that abolishes the macropinocytotic and endocytotic nanoparticle internalization pathways that occur without complexation. SupraCell formation was shown to be generalizable to wide classes of nanoparticles and various types of cells. It induces a spore-like state, wherein cells do not replicate or spread on surfaces but are endowed with extremophile properties, e.g., resistance to osmotic stress, reactive oxygen species, pH, and UV exposure, along with abiotic properties like magnetism, conductivity, and multi-fluorescence. Upon de-complexation cells return to their normal replicative states. SupraCells represent a new class of living hybrid materials with a broad range of functionalities. Enhancing or augmenting the performance of mammalian cells could result in new classes of smart responsive living materials. Mammalian cells exhibit complex functionalities like sensing, signal transduction, and protein expression, but they remain fragile and highly susceptible to intracellular and extracellular stressors. [1] So far, to impart delicate mammalian cells with greater cellular durability, such as enhanced resistance against UV, freezing, and enzymatic attack, etc., a series of coating strategies/nanotechniques have been developed to

The development of hybrid nanomaterials mimicking antifreeze proteins that can modulate/inhibit the growth of ice crystals for cell/tissue cryopreservation has attracted increasing interests. Herein, we describe the first utilization of zirconium (Zr)-based metal−organic framework (MOF) nanoparticles (NPs) with well-defined surface chemistries for the cryopreservation of red blood cells (RBCs) without the need of any (toxic) organic solvents. Distinguishing features of this cryoprotective approach include the exceptional water stability, low hemolytic activity, and the long periodic arrangement of organic linkers on the surface of MOF NPs, which provide a precise spacing of hydrogen donors to recognize and match the ice crystal planes. Five kinds of Zr-based MOF NPs, with different pore size, surface chemistry, and framework topologies, were used for the cryoprotection of RBCs. A "splat" assay confirmed that MOF NPs not only exhibited ice recrystallization inhibition activities but also acted as a "catalyst" to accelerate the melting of ice crystals. The human RBC cryopreservation tests displayed RBC recoveries of up to ∼40%, which is higher than that obtained via commonly used hydroxyethyl starch polymers. This cryopreservation approach will inspire the design and utilization of MOF-derived nanoarchitectures for the effective cryopreservation of various cell types as well as tissue samples.