Daniel Larrañaga-Ordaz

Since the discovery of extracorporeal lithotripsy, there has been an increased interest in studying shock wave-induced cavitation, both to improve this technique and to explore novel biotechnological applications. As shock waves propagate through fluids, pre-existing microbubbles undergo expansion and collapse, emitting high-speed microjets. These microjets play a crucial role in the pulverization of urinary stones during lithotripsy and have been utilized in the delivery of drugs and genetic materials into cells. Their intensity can be amplified using tandem shock waves, generated so that the second wave reaches the bubbles, expanded by the first wave, during their collapse. Nevertheless, there is little information regarding the control of microjet emissions. This study aimed to demonstrate that specific effects can be obtained by tuning the delay between the first and second shock waves. Suspensions containing Aspergillus niger, a microscopic fungus that produces metabolites with high commercial value, were exposed to single-pulse and tandem shock waves. Morphological changes were analyzed by scanning and transmission electron microscopy. Proteins released into the medium after shock wave exposure were also studied. Our findings suggest that, with enhanced control over cavitation, the detachment of proteins using conventional methods could be significantly optimized in future studies.

This work proposes a sonochemical biosynthesis of magnetoplasmonic nanostructures of Fe₃O₄ decorated with Au and Ag. The magnetoplasmonic systems, such as Fe₃O₄ and Fe₃O₄-Ag, were characterized structurally and magnetically. The structural characterizations reveal the magnetite structures as the primary phase. Noble metals, such as Au and Ag, are present in the sample, resulting in a structure-decorated type. The magnetic measurements indicate the superparamagnetic behavior of the Fe₃O₄-Ag and Fe₃O₄-Au nanostructures. The characterizations were carried out by X-ray diffraction and scanning electron microscopy. Complementarily, antibacterial and antifungal assays were carried out to evaluate the potential properties and future applications in biomedicine.

Shock waves, as used in medicine, can induce cell permeabilization, genetically transforming filamentous fungi; however, little is known on the interaction of shock waves with the cell wall. Because of this, the selection of parameters has been empirical. We studied the influence of shock waves on the germination of Aspergillus niger, to understand their effect on the modulation of four genes related to the growth of conidia. Parameters were varied in the range reported in protocols for genetic transformation. Vials containing conidia in suspension were exposed to either 50, 100 or 200 single-pulse or tandem shock waves, with different peak pressures (approximately 42, 66 and 83 MPa). In the tandem mode, three delays were tested. To equalize the total energy, the number of tandem “events” was halved compared to the number of single-pulse shock waves. Our results demonstrate that shock waves do not generate severe cellular effects on the viability and germination of A. niger conidia. Nevertheless, increase in the aggressiveness of the treatment induced a modification in four tested genes. Scanning electron microscopy revealed significant changes to the cell wall of the conidia. Under optimized conditions, shock waves could be used for several biotechnological applications, surpassing conventional techniques.

Shock waves, as used in medicine, can induce cell permeabilization, genetically transforming filamentous fungi; however, little is known on the interaction of shock waves with the cell wall. Because of this, the selection of parameters has been empirical. We studied the influence of shock waves on the germination of Aspergillus niger, to understand their effect on the modulation of four genes related to the growth of conidia. Parameters were varied in the range reported in protocols for genetic transformation. Vials containing conidia in suspension were exposed to either 50, 100 or 200 single-pulse or tandem shock waves, with different peak pressures (approximately 42, 66 and 83 MPa). In the tandem mode, three delays were tested. To equalize the total energy, the number of tandem “events” was halved compared to the number of single-pulse shock waves. Our results demonstrate that shock waves do not generate severe cellular effects on the viability and germination of A. niger conidia. Nevertheless, increase in the aggressiveness of the treatment induced a modification in the four genes tested. Scanning electron microscopy revealed significant changes to the cell wall of the conidia. Under optimized conditions, shock waves could be used for several biotechnological applications, surpassing conventional techniques.

Currently, the use of sustainable chemistry as an ecological alternative for the generation of products or processes that are free of a polluting substance has assumed a preponderant role. The aim of this work is to propose a bioinspired, facile, low cost, non-toxic, and environmentally friendly alternative to obtaining magnetic nanoparticles with a majority phase of magnetite (Fe₃O₄). It is important to emphasize that the synthesis was based on the chemical reduction through the Cnicus benedictus extract, whose use as reducing agent has not been reported in the synthesis of iron oxides nanoparticles. In addition, the Cnicus benedictus is an abundant endemic plant in Mexico with several medicinal properties and a large number of natural antioxidants. The obtained nanoparticles exhibited significant magnetic and antibacterial properties and an enhanced photocatalytic activity. The crystallite size of the Fe₃O₄ nanoparticles (Fe₃O₄ NP’s) was calculated by the Williamson-Hall method. The photocatalytic properties of the Fe₃O₄ NP’s were studied by kinetics absorptions models in the Congo red (CR) degradation. Finally, the antibacterial effects of the Fe₃O₄ NPs were evaluated mediated the Kirby–Bauer method against Escherichia coli and Staphylococcus aureus bacteria. This route offers a green alternative to obtain Fe₃O₄ NPs with remarkable magnetic, photocatalytic, and antibacterial properties.