Magnetically steerable bacterial microrobots moving in 3D biological matrices for stimuli-responsive cargo delivery.

Bacterial biohybrids, composed of self-propelling bacteria carrying micro/nanoscale materials, can deliver their payload to specific regions under magnetic control, enabling additional frontiers in minimally invasive medicine. However, current bacterial biohybrid designs lack high-throughput and facile construction with favorable cargoes, thus underperforming in terms of propulsion, payload efficiency, tissue penetration, and spatiotemporal operation. Here, we report magnetically controlled bacterial biohybrids for targeted localization and multistimuli-responsive drug release in three-dimensional (3D) biological matrices. Magnetic nanoparticles and nanoliposomes loaded with photothermal agents and chemotherapeutic molecules were integrated onto Escherichia coli with ~90% efficiency. Bacterial biohybrids, outperforming previously reported E. coli-based microrobots, retained their original motility and were able to navigate through biological matrices and colonize tumor spheroids under magnetic fields for on-demand release of the drug molecules by near-infrared stimulus. Our work thus provides a multifunctional microrobotic platform for guided locomotion in 3D biological networks and stimuli-responsive delivery of therapeutics for diverse medical applications.

Design and in vitro, in vivo evaluation of antioxidant bioadhesive gels for burn treatment.

Burn wounds are frequently encountered health problems, which need a new treatment approach especially in terms of good patient compliance. Availability of use of antioxidant agents and bio-adhesive gels in tissue healing can be an alternative as a new approach for wound healing. Antioxidant taurine containing bio-adhesive gels were prepared by using carbopol (CP) 940 and 934. Rheological and texture analyses were carried out on bio-adhesive gels for in vitro characterization. Wound model on Wistar rats was used to evaluate the in vivo evaluation of gels. Rheological and texture analyses showed that a carbopol bioadhesive gel has acceptable topically use dosage characteristics and in combination with Taurine it presented a successful wound healing effect via antioxidant parameters. In conclusion, bio-adhesive CP 940 (2%) gel containing 50 mM taurine could be promising in the treatment of burns by balancing oxidative stress.

An examination of carbopol hydrogel/organogel bigels of thymoquinone prepared by microwave irradiation method.

Nigella sativa L. is shown wide spread over the world and contains many useful phytochemicals. Much of the biological activity of the seeds has been shown due to the presence of thymoquinone (TQ). Its poor aqueous solubility of TQ hinders its delivery to target site. The aim of this work was to prepare TQ bigels composed of Carbopol 974 P NF (C974) in PEG 400 (organogel) or C974 in water (hydrogel) with microwave heating method. A novel technique, high speed homogenization followed by microwave heating, was used to prepare organogels. The pH, electrical conductivity, differential scanning calorimetry, rheological properties, and morphological structure of the formulations have been evaluated, and the effect of microwave on drug content and TQ antioxidant activity has been investigated. The bigels of TQ were successfully produced via high-speed homogenization followed by microwave-assisted heating for the first time in this study. Highly lipophilic TQ was successfully dissolved in organogel, and it was not affected from the microwaves. It can be stated that microwave heating is a promising method to obtain C974 organogels and thus bigels with appropriate above indicated investigated physicochemical characteristics. The time and energy consumption could be decreased with microwave-assisted heating, especially for gel preparation in the field of pharmaceuticals.