Template free solvothermal synthesis of single crystal magnetic Fe 3 O 4 hollow spheres, their interaction with bovine serum albumin and antibacterial activities

Immobilized PAD4 enzyme on magnetic nanoparticles for screening natural inhibitors from traditional Chinese medicines

Dysregulation of peptidyl arginine deiminase 4 (PAD4) is involved in a variety of diseases including rheumatoid arthritis (RA) and Alzheimer's disease (AD), and it has emerged as potential and promising therapeutic target. However, no PAD4 inhibitor is ready for clinical use. Immobilized enzyme screening technology has gained increasing attention due to its low cost, reusability, easy separation from the reaction mixture, and resistance to changes in environmental conditions. In this study, PAD4 was immobilized on the magnetic nanoparticles (MNP) to prolong its activity stability, and a simple and rapid screening strategy of traditional Chinese medicine inhibitors based on immobilized PAD4 was established. The PAD4 enzyme was immobilized on magnetic nanoparticles (MNP) via Schiff base reaction using glutaraldehyde (GA) as crosslinking agent. Compared with free PAD4, the resulting MNP@GA@PAD4 exhibited an enhanced tolerance to temperature and storage stability, and its reusability was greatly improved with 66 % of initial enzyme activity after being recycled 10 times. The inhibitory activity of the immobilized PAD4 was assessed using two known PAD4 inhibitors GSK484 and BB-Cl-amidine. The semi-maximum inhibitory concentrations (IC50) of GSK484 and BB-Cl-amidine for MNP@GA@PAD4 were 1.00 and 0.97 μM, respectively, for free PAD4 were 0.64 and 0.85 μM, respectively. Finally, the MNP@GA@PAD4 was employed to rapid screen of natural PAD4 inhibitors from forty traditional Chinese medicines (TCMs). Under the same conditions, the controlled experiment was conducted with free PAD4. The screening results of TCMs inhibitors on MNP@GA@PAD4 and free PAD4 were similar, the alcohol extracts of Cinnamomi Cortex and Caryophylli Flos had significant inhibitory effects on PAD4 enzyme activity. The IC50 values of Cinnamomi Cortex extract for MNP@GA@PAD4 and free PAD4 were determined as 27 and 48 μg/mL, respectively. The IC50 values of Caryophylli Flos extracts for MNP@GA@PAD4 and free PAD4 were determined as 48 and 32 μg/mL, respectively. For the first time, this study proposed a method to immobilize PAD4 on magnetic materials, and developed a rapid, reusable and feasible strategy to screening natural PAD4 inhibitors from TCMs.

Lithium entrapped chitosan nanoparticles to reduce toxicity and increase cellular uptake of lithium

Lithium carbonate is an effective drug against bipolar disorders. Direct use of lithium carbonate has been reported to result in lithium toxication and pulmonary complications. With chitosan micro and nanoparticles gaining attention for their protein absorption, drug targeting and improved dissolution rate of sparingly water-soluble drugs, this work has focused on chitosan loaded Li as a possible alternative to Li alone for cellular uptake. Well standardized ionic gelation technique employed in this study resulted in Li loaded chitosan nanoparticles with hydrodynamic diameter below 300 nm and zeta potential of + 30 mV and oval morphology. Through various techniques electrostatic interaction as well as Claritin dependent endocytic pathway is suggested as facilitating 1.3 times increase in cell proliferation in lithium carbonate loaded chitosan nanoparticles treated PC12 cells. A controlled Li release to the extent of less than 50% in 48 h from the nanoparticle was observed. This observation has very high significance as it ensures that the lithium toxicity can be avoided. These results indicated that chitosan is a promising carrier for lithium carbonate and may improve its therapeutic efficacy and also overcome toxicity during its use in the treatment of neuropsychiatric disorders.