Enhancement of the biological autoluminescence by mito-liposomal gold nanoparticle nanocarriers

One of the most important barriers to the detection of the biological autoluminescence (BAL) from biosystems using a non-invasive monitoring approach, in both the in vivo and the in vitro applications, is its very low signal intensity (< 1000 photons/s/cm²). Experimental studies have revealed that the formation of electron excited species, as a result of reactions of biomolecules with reactive oxygen species (ROS), is the principal biochemical source of the BAL which occurs during the cell metabolism. Mitochondria, as the most important organelles involved in oxidative metabolism, are considered to be the main intracellular BAL source. Hence, in order to achieve the BAL enhancement via affecting the mitochondria, we prepared a novel mitochondrial-liposomal nanocarrier with two attractive features including the intra-liposomal gold nanoparticle synthesizing ability and the mitochondria penetration capability. The results indicate that these nanocarriers (with the average size of 131.1 ± 20.1 nm) are not only able to synthesize the gold nanoparticles within them (with the average size of 15 nm) and penetrate into the U2OS cell mitochondria, but they are also able to amplify the BAL signals. Our results open new possibilities for the use of biological autoluminescence as a non-invasive and label-free monitoring method in nanomedicine and biotechnology.

Resistance of nanobacteria isolated from urinary and kidney stones to broad-spectrum antibiotics

BACKGROUND AND OBJECTIVE

Nanoscopic life forms called Nanobacteria or calcifying nanoparticles (CNP) are unconventional agents. These novel organisms are very small (0.1 to 0.5 microns) and possess unusual properties such as high resistance to heat and routine antimicrobial agents. Nanobacteria are 100 times smaller than bacteria and protected by a shell of apatite, so they could be as candidate for emerging and progress of in vivo pathological calcification. In this study, the inhibitory effect of broad-spectrum antibiotics on growth of these new forms of life has been investigated.

MATERIAL AND METHODS

Powdered urinary and kidney stones were demineralized with HCl and neutralized with appropriate buffers and became filtered. Finally suspension was incubated in DMEM medium with Fetal Bovine Serum (FBS) and broad-spectrum antibiotics (100U/ml for penicillin and 100μg/ml for streptomycin) for 60 days.

RESULTS

In the presence of broad-spectrum antibiotics, Scanning Electron Micrographs (SEM) showed a spherical shape of these nanobacteria. Also, Energy Dispersive X-ray spectroscopy (EDS) showed a pick for calcium and phosphor. Transmission Electron Microscopy (TEM) results illustrated cover around the nanobacteria.

CONCLUSION

The growth of calcifying nanoparticles after adding the broad-spectrum antibiotics may be due to their apatite hard shells supporting them against penetration of the antibiotics.