Periodic Reporting for period 1 - MIPhmotors (Molecularly Imprinted Photocatalytic light-driven micro/nanomotors for selective degradation and detection of pollutants in water and food)
Période du rapport: 2021-08-01 au 2023-07-31
The rapid pace of industrialization together with diverse human activities makes various harmful pollutants, including micro/nanoplastics, small organic molecules, heavy metal ions, and pathogenic microorganisms, drain in the environment. Plastics are one of the major sources of environmental pollution, especially in water bodies. There, plastic waste fragments into smaller and more dangerous pieces, namely microplastics (< 5 mm) and nanoplastics (<1000 nm). These plastic particles are particularly harmful as they absorb other pollutants on their surface, increasing their toxicity. Moreover, they are ingested by fish and propagate through the food chain or directly contaminate drinking water systems, posing serious risks to the health of all living beings. At the same time, to fulfill the increasing demand for food, the use of pesticides in agriculture has been continuously intensified. However, it is demonstrated that less than 1% of the applied pesticide reaches and destroys the pest, while the remaining contaminates soil, water, and food.The European Commission has stated the importance of addressing this issue in the European Green Deals "Eliminating Pollution" and "From farm to fork". Therefore, there is an urgent need for practical strategies to remove and quantify pollutants in water. MIPhmotors aims to address these challenges by developing self-propelled micro/nanorobots able to propel in water under light irradiation and, simultaneously, accelerate the capture or degradation of water pollutants, followed by their electrochemical detection. Micro/nanorobots represent the frontier of the research in materials science and nanotechnology, combining the unique physicochemical properties of micro/nanoscale materials with the active motion dimension, accelerating a variety of diffusion-limited processes or remotely operating in difficult to access areas. They can be powered by chemical fuels or external energy sources (light and magnetic fields), and programmed to perform desired tasks.
On these bases, MIPhmotors overall objectives are:
1) the formulation of light-powered micro/nanorobots based on metal/semiconductor structures to speed up the capture or degradation of water pollutants;
2) the electrochemical detection of water pollutants using low-cost and portable screen-printed electrodes, which can be in principle utilized in situ (e.g. in natural water bodies) without requiring any sample analysis in laboratories with bulky and expensive equipment manoeuvred by expert staff.
On these bases, MIPhmotors overall objectives are:
1) the formulation of light-powered micro/nanorobots based on metal/semiconductor structures to speed up the capture or degradation of water pollutants;
2) the electrochemical detection of water pollutants using low-cost and portable screen-printed electrodes, which can be in principle utilized in situ (e.g. in natural water bodies) without requiring any sample analysis in laboratories with bulky and expensive equipment manoeuvred by expert staff.
The researcher produced a variety of micro/nanorobots for environmental remediation, sensing, and biomedicine. Particularly, he reviewed the literature on micro/nanorobots for micro/nanoplastics capture and degradation. Then, he exploited the multi-layered structure of exfoliated Ti3C2 MXene, belonging to the class of 2D materials, to produce light-powered microrobots through an optimal thermal annealing process, followed by Pt deposition by sputtering and magnetic iron oxide nanoparticles loading. The microrobots were capable of moving in the 3D space and used to electrostatically trap nanoplastics in water inside the multi-layered structure. Subsequently, the microrobots were transferred onto low-cost and portable screen-printed electrodes thanks to their magnetic properties, enabling the detection of the captured nanoplastics through electrochemical techniques. Moreover, he studied the movement of dual light/magnetic field powered micrororobots consisting of peanut-shaped hematite microparticles covered by a TiO2 layer by atomic layer deposition. These microrobots showed rapid movement under light-irradiation and magnetic field controlled directionality to photocatalytically degrade pesticides in water, such as the 2,4D. The researcher also wrote a review article on DNA-based micro/nanorobots, inspiring the design of intelligent micro/nanomachines that take advantage of the high programmability of DNA to perform a variety of complicate tasks in a controllable way. Furthermore, he contributed to various research activities of the supervisor's research group at the host institution related to the project. For example, he developed self-propelled multifunctional microrobots harboring chiral supramolecular selectors and fluorescent CdS quantum dots to "on-the-fly" discriminate enantiomers, such as L- and D-Tryptophan. He conceptualized different light-powered and magnetic hematite-based microrobots which were used by collaborators for different applications, including the water remediation from insoluble matter and polymers through self-assembled microchains formed by cubic microrobots, the non-contact cells transport and prostate cancer cells killing by dendrite-shaped microrobots. He contributed to the recording, analysis, and interpretation of the multi-mode motion behavior of visible-light powered Ag/black TiO2 nanorobots utilized for the eradication of bacterial biofilms from facial Ti implants.
The project key results demonstrated a great potential for dissemination and exploitation, including presentations at the group meetings of the research group at the host institution, presentation at national and international conferences (108° Congress of the Italian Physical Society in Milan and Seventh International Conference on Multifunctional, Hybrid and Nanomaterials in Genoa), several open access publications (among which a research article published in the prestigious Nature Communications journal), and contribution to different research activities at the host institution.
The project key results demonstrated a great potential for dissemination and exploitation, including presentations at the group meetings of the research group at the host institution, presentation at national and international conferences (108° Congress of the Italian Physical Society in Milan and Seventh International Conference on Multifunctional, Hybrid and Nanomaterials in Genoa), several open access publications (among which a research article published in the prestigious Nature Communications journal), and contribution to different research activities at the host institution.
The researcher developed a sensor to detect nanoplastics in water samples. Such a sensors exploit self-propelled light-powered MXene-derived microrobots to preconcentrate nanoplastics in low volume water samples and enable their detection through electrochemical techniques using low-cost and portable screen-printed electrodes. Specifically, the sensor was able to detect the presence of nanoplastics and determine their concentration after a proper calibration. While preliminary tests have been only performed in the lab, the proposed methodology is suitable for on site detection of nanoplastics and, in principle, microplastics in natural water bodies using simple and cheap equipment without the need for specialized staff. This represents a significant progress beyond the state of the art, since current techniques to identify micro/nanoplastics in water are mainly limited to the laboratory scale and necessitates trained personnel. Moreover, the nanoplastics capture ability by the microrobots is promising for their application in the remediation of plastic-contaminated waters. In addition to the MXene-derived microrobots, the other light-powered micro/nanorobots developed in the project are promising for water purification from plastics as well as small organic pollutants (such as pesticides) and microorganisms. Indeed, the active movement of the micro/nanorobots allows to greatly accelerate the removal/degradation of water contaminants, overcoming traditional approaches involving static micro/nanomaterials that are commonly limited by passive diffusion. Finally, the hematite-based microrobots hold considerable promise for the prostate cancer therapy. Due to their biocompatibility and magnetic actuation it is expected that they could be safely navigated inside the human body until reaching the tumor region and in situ photothermally activated to induce cancer cells death.