Chemical Microrobots as Self-Propelled Microbrushes against Dental Biofilm

Mouths offer the perfect environments for microbial cell formation, promoting the growth of biofilms, for example, on teeth. Dental biofilm exhibits strong resistance to antibiotics and is a cause of many dental diseases. Common strategies for dental biofilm removal involve the addition of high concentrations of hydrogen peroxide (H2O2), which increases tooth sensitivity, or mechanical procedures. Here, we report a different approach based on self-propelled micromachines with high antibacterial activity for the degradation of dental biofilm. Such microrobots use low concentrations of fuel for their propulsion, and they achieve an efficient dental biofilm disruption in only 5 min of treatment. Moreover, these microrobots are biocompatible with epidermal and organ cells and may stimulate the immune system to fight against microbial infection. This approach of exploiting the active motion of bubble-propelled catalytic micromachines for oral biofilm disruption may open the door for more efficient and sophisticated treatments in dentistry

Multimodal-driven magnetic microrobots with enhanced bactericidal activity for biofilm eradication and removal from titanium mesh

Modern micro/nanorobots can perform multiple tasks for biomedical and environmental applications. Particularly, magnetic microrobots can be completely controlled by a rotating magnetic field and their motion powered and controlled without the use of toxic fuels, which makes them most promising for biomedical application. Moreover, they are able to form swarms, allowing them to perform specific tasks at a larger scale than a single microrobot. In this work, they developed magnetic microrobots composed of halloysite nanotubes as backbone and iron oxide (Fe3O4) nanoparticles as magnetic material allowing magnetic propulsion and covered these with polyethylenimine to load ampicillin and prevent the microrobots from disassembling. These microrobots exhibit multimodal motion as single robots as well as in swarms. In addition, they can transform from tumbling to spinning motion and vice-versa, and when in swarm mode they can change their motion from vortex to ribbon and back again. Finally, the vortex motion mode is used to penetrate and disrupt the extracellular matrix of Staphylococcus aureus biofilm colonized on titanium mesh used for bone restoration, which improves the effect of the antibiotic’s activity. Such magnetic microrobots for biofilm removal from medical implants could reduce implant rejection and improve patients’ well-being.Web of Science352

Mycotoxins: Biotransformation and Bioavailability Assessment Using Caco-2 Cell Monolayer

The determination of mycotoxins content in food is not sufficient for the prediction of their potential in vivo cytotoxicity because it does not reflect their bioavailability and mutual interactions within complex matrices, which may significantly alter the toxic effects. Moreover, many mycotoxins undergo biotransformation and metabolization during the intestinal absorption process. Biotransformation is predominantly the conversion of mycotoxins meditated by cytochrome P450 and other enzymes. This should transform the toxins to nontoxic metabolites but it may possibly result in unexpectedly high toxicity. Therefore, the verification of biotransformation and bioavailability provides valuable information to correctly interpret occurrence data and biomonitoring results. Among all of the methods available, the in vitro models using monolayer formed by epithelial cells from the human colon (Caco-2 cell) have been extensively used for evaluating the permeability, bioavailability, intestinal transport, and metabolism of toxic and biologically active compounds. Here, the strengths and limitations of both in vivo and in vitro techniques used to determine bioavailability are reviewed, along with current detailed data about biotransformation of mycotoxins. Furthermore, the molecular mechanism of mycotoxin effects is also discussed regarding the disorder of intestinal barrier integrity induced by mycotoxins