Digital light processing bioprinting favors biofabrication of tissues with improved structural complexity. However, soft-tissue fabrication with this method remains a challenge to balance the physical performances of the bioinks for high-fidelity bioprinting and suitable microenvironments for the encapsulated cells to thrive. Here, we propose a molecular cleavage approach, where hyaluronic acid methacrylate (HAMA) is mixed with gelatin methacryloyl to achieve high-performance bioprinting, followed by selectively enzymatic digestion of HAMA, resulting in tissue-matching mechanical properties without losing the structural complexity and fidelity. Our method allows cellular morphological and functional improvements across multiple bioprinted tissue types featuring a wide range of mechanical stiffness, from the muscles to the brain, the softest organ of the human body. This platform endows us to biofabricate mechanically precisely tunable constructs to meet the biological function requirements of target tissues, potentially paving the way for broad applications in tissue and tissue model engineering.

To optimize mesenchymal stem cell differentiation and antibacterial properties of titanium (Ti), nano-sized zinc oxide (ZnO) particles with tunable concentrations were incorporated into TiO 2 nanotubes (TNTs) using a facile hydrothermal strategy. It is revealed here for the first time that the TNTs incorporated with ZnO nanoparticles exhibited better biocompatibility compared with pure Ti samples (controls) and that the amount of ZnO (tailored by the concentration of Zn(NO 3 ) 2 in the precursor) introduced into TNTs played a crucial role on their osteogenic properties. Not only was the alkaline phosphatase activity improved to about 13.8 U/g protein, but the osterix, collagen-I, and osteocalcin gene expressions was improved from mesenchymal stem cells compared to controls. To further explore the mechanism of TNTs decorated with ZnO on cell functions, a response surface mathematical model was used to optimize the concentration of ZnO incorporation into the Ti nanotubes for stem cell differentiation and antibacterial properties for the first time. Both experimental and modeling results confirmed ( R 2 values of 0.8873–0.9138 and 0.9596–0.9941, respectively) that Ti incorporated with appropriate concentrations (with an initial concentration of Zn(NO 3 ) 2 at 0.015 M) of ZnO can provide exceptional osteogenic properties for stem cell differentiation in bone cells with strong antibacterial effects, properties important for improving dental and orthopedic implant efficacy.

PurposeThis work presents the preparation of a nanocomposite of ampicillin-conjugated gold nanoparticles (AuNPs) and self-assembled rosette nanotubes (RNTs), and evaluates its antibacterial properties against two strains of drug-resistant bacteria (Staphylococcus aureus [S. aureus], methicillin-resistant S. aureus [MRSA]).Materials and methodsSmall, nearly monodisperse AuNPs (1.43±0.5 nm in diameter) nucleated on the surface of polyethylene glycol-functionalized RNTs in a one-pot reaction. Upon conjugation with ampicillin, their diameter increased to 1.86±0.32 nm. The antibacterial activity of the nanocomposite against S. aureus and MRSA was tested using different concentrations of ampicillin. The cytocompatibility of the nanocomposite was also tested against human dermal fibroblasts.ResultsBased on bacterial inhibition studies, the nanocomposite demonstrated enhanced antibiotic activity against both bacterial strains. The minimum inhibitory concentration (MIC) of the nanocomposite against S. aureus was found to be 0.58 μg/mL, which was 18% lower than ampicillin alone. The nanocomposite also exhibited a 20 hrs MIC of 4 μg/mL against MRSA, approximately 10–20 times lower than previously reported values for ampicillin alone. In addition, at concentrations of 4 μg/mL of ampicillin (70 μg/mL of AuNPs), the nanocomposite showed negligible cytotoxic effects.ConclusionOur findings offer a new approach for the treatment of drug-resistant bacteria by potentiating inhibitory effects of existing antibiotics, and delivering them using a non-toxic formulation.

Sodium-glucose co-transporter 2 (SGLT-2) is a major transport protein responsible for reabsorption of glucose from the kidney back to the bloodstream. Inhibiting this protein effectively lowers the glucose level of diabetic patients; however, the use of synthetic SGLT-2 inhibitors has been linked to some serious adverse effects. There is a need to identify safer alternatives that are equally or more effective as the current inhibitor drugs. Phytochemicals are known for their efficacy as herbal remedies, but these molecules remain underexplored as source of therapeutic agents. In this study, we performed in silico screening to identify potential SGLT-2 inhibitors from the 21 phytochemicals from Centella asiatica. Docking results identified eleven compounds with estimated binding energies comparable to that of known inhibitors drugs. The stability of the complexes was then elucidated using 100 ns MD simulations. From our dynamic binding free energy calculations using MM/PBSA, asiaticoside, betulinic acid, centellasapogenol, methyl brahmate, and rutin exceeded at least one of the binding energies of the reference compounds, which highlights their strong affinity towards SGLT-2. Among the five, betulinic acid, centellasapogenol, and methyl brahmate maintained their structural stability to the same extent as the references and exhibited better oral bioavailability and excellent drug-like properties. Because of these results, it is recommended to prioritize betulinic acid, centellasapogenol, and methyl brahmate in future in vitro and in vivo studies to verify their potential as inhibitor drugs for diabetes therapies.

Two N-bridged pyrido[4,3-d]pyrimidine derivatives were synthesized toward realization of a self-assembled bis-rosette cage, in organic media. Starting from commercially available malononitrile dimer and dimethyl 5-aminoisophthalate, the target molecules were synthesized in 11 steps using a convergent approach. The final bridged compounds were characterized by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. The hierarchical self-assembly of the nanocages into rosette nanotubes and nanobundles was established by electron microscopy and molecular modelling studies.