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A hydrogel that can deliver both proteins and cells enables the local microenvironment of transplanted cells to be manipulated with a single injection. Toward this goal, we designed a hydrogel suitable for the co-delivery of neural stem cells and chondroitinase ABC (ChABC), a potent enzyme that degrades the glial scar that forms after central nervous system (CNS) injury. We leveraged the inverse electron-demand Diels-Alder reaction between norbornene and methylphenyltetrazine to form rapidly gelling (

Cell-penetrating peptides are a promising therapeutic strategy for a wide variety of degenerative diseases, ageing, and cancer. Among the multitude of cell-penetrating peptides, PepFect14 has been preferentially used in our laboratory for oligonucleotide delivery into cells and in vivo mouse models. However, this activity has mainly been reported towards cytoplasm and nuclei, while the mentioned disorders have been linked to mitochondrial defects. Here, we report a library generated from a combinatorial covalent fusion of a mitochondrial-penetrating peptide, mtCPP1, and PepFect14 in order to deliver therapeutic biomolecules to influence mitochondrial protein expression. The non-covalent complexation of these peptides with oligonucleotides resulted in nano-complexes affecting biological functions in the cytoplasm and on mitochondria. This delivery system proved to efficiently target mitochondrial genes, providing a framework for the development of mitochondrial peptide-based oligonucleotide technologies with the potential to be used as a treatment for patients with mitochondrial disorders.

3D printed polycaprolactone (PCL) has potential as a scaffold for bone tissue engineering, but the hydrophobic surface may hinder optimal cell responses. The surface properties can be improved by coating the scaffold with cellulose nanofibrils material (CNF), a multiscale hydrophilic biocompatible biomaterial derived from wood. In this study, human bone marrow-derived mesenchymal stem cells were cultured on tissue culture plates (TCP) and 3D printed PCL scaffolds coated with CNF. Cellular responses to the surfaces (viability, attachment, proliferation, and osteogenic differentiation) were documented. CNF significantly enhanced the hydrophilic properties of PCL scaffolds and promoted protein adsorption. Live/dead staining and lactate dehydrogenase release assays confirmed that CNF did not inhibit cellular viability. The CNF between the 3D printed PCL strands and pores acted as a hydrophilic barrier, enhancing cell seeding efficiency, and proliferation. CNF supported the formation of a well-organized actin cytoskeleton and cellular production of vinculin protein on the surfaces of TCP and PCL scaffolds. Moreover, CNF-coated surfaces enhanced not only alkaline phosphatase activity, but also collagen Type-I and mineral formation. It is concluded that CNF coating enhances cell attachment, proliferation, and osteogenic differentiation and has the potential to improve the performance of 3D printed PCL scaffolds for bone tissue engineering.

We have designed photocurable, telechelic macromonomers consisting of random oligo(e-caprolactone-co-p-dioxanone), oligo(CL-co-DX), and demonstrated their suitability for preparing pliable polyester networks whose properties resemble those of gels. A versatile and effective metal-free co-oligomerization, catalyzed by diphenyl phosphate, was developed in bulk and at room temperature. A high rate of conversion of monomers was achieved and oligo(CL-co-DX)s with different composition and topology were obtained with controlled molar mass, approx. 2000 g mol−1, low dispersity and a random distribution of the two monomeric units. Kinetics analysis of the reaction disclosed a faster incorporation rate for the p-dioxanone (DX) than e-caprolactone (CL). The extrapolated rate constant, kDX, was 0.030 min−1 against a kCL of 0.013 min−1. The reactivity ratios were respectively 2.7 (rDX) and 0.28 (rCL). A detailed NMR analysis was performed to elucidate the structure of the co-oligomers, which could be precisely controlled by varying the monomer feed ratio and initiator. Depending on the composition, amorphous to semicrystalline oligomers with melting points close to room temperature were obtained, which after acrylation of the chain-end gave polyester networks with high swelling capacity up to 700%, and water uptake up to 70%.

Cholangiocytes form an intricate network of bile ducts to enable proper liver function; yet, recapitulating human stem cell differentiation to cholangiocytes in vitro requires Notch signaling and s ...

Degradable polymers based on α-hydroxy acids and α-amino acids constitutes a potent class of biomaterials, combining high hydrolyzability with structural features that mimics peptides. Driven by the design criteria to construct isolated α-amino acid units along a main polylactide chain, a copolymer system was developed based on two monomers with distinctly different equilibrium behaviors. This was uncovered by detailed understanding on the kinetic and thermodynamic polymerizability of 3S,6S-dimethylmorpholine-2,5-dione (DMMD) and L-lactide (LLA) at low reaction temperatures. Under Bronsted base-promoted ring-opening copolymerization (ROCOP) conditions, the equilibrium nature of the copolymerization was shown susceptible to changes in the system, such as catalyst basicity, solvent polarity and initial monomer concentrations. Subsequently, high equilibrium conversions of both monomers with control over molecular weight and dispersity could be achieved within short reaction times by modulation of these factors. Thermodynamic elucidations of the copolymerization system revealed that DMMD behaved as an unstrained monomer with a large propagation barrier, favored by an increase in polymerization temperature. Ultimately, the high propagation barrier of DMMD in the system resulted in a kinetically controlled mechanism with the formation of completely isolated units of DMMD along the polylactide backbone. These results extend current ROCOP strategies of morpholine-2,5-diones and cyclic esters to a mild and selective copolymerization platform for the construction of sequence-controlled α-amino acid decorated polyesters for medical applications.