Staff member


Jemish Parmar

PhD Student
Smart Nano-Bio-Devices
jparmar@ibecbarcelona.eu
+34 934 020291
Staff member publications

Vilela, D., Stanton, M. M., Parmar, J., Sánchez, S., (2017). Microbots decorated with silver nanoparticles kill bacteria in aqueous media ACS Applied Materials and Interfaces 9, (27), 22093-22100

Water contamination is one of the most persistent problems of public health. Resistance of some pathogens to conventional disinfectants can require the combination of multiple disinfectants or increased disinfectant doses, which may produce harmful byproducts. Here, we describe an efficient method for disinfecting Escherichia coli and removing the bacteria from contaminated water using water self-propelled Janus microbots decorated with silver nanoparticles (AgNPs). The structure of a spherical Janus microbot consists of a magnesium (Mg) microparticle as a template that also functions as propulsion source by producing hydrogen bubbles when in contact with water, an inner iron (Fe) magnetic layer for their remote guidance and collection, and an outer AgNP-coated gold (Au) layer for bacterial adhesion and improving bactericidal properties. The active motion of microbots increases the chances of the contact of AgNPs on the microbot surface with bacteria, which provokes the selective Ag+ release in their cytoplasm, and the microbot self-propulsion increases the diffusion of the released Ag+ ions. In addition, the AgNP-coated Au cap of the microbots has a dual capability of capturing bacteria and then killing them. Thus, we have demonstrated that AgNP-coated Janus microbots are capable of efficiently killing more than 80% of E. coli compared with colloidal AgNPs that killed only less than 35% of E. coli in contaminated water solutions in 15 min. After capture and extermination of bacteria, magnetic properties of the cap allow collection of microbots from water along with the captured dead bacteria, leaving water with no biological contaminants. The presented biocompatible Janus microbots offer an encouraging method for rapid disinfection of water.

Keywords: Bactericidal, Magnetic control, Micromotors, Microswimmers, Self-propulsion, Silver nanoparticles


Vilela, Diana, Parmar, Jemish, Zeng, Yongfei, Zhao, Yanli, Sánchez, Samuel, (2016). Graphene based microbots for toxic heavy metal removal and recovery from water Nano Letters 16, (4), 2860-2866

Heavy metal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nano-systems and nanomaterials for fast and efficient removal of pollutants and heavy metals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer and removal of a heavy metal -lead-, and its subsequent recovery for recycling purposes. Microbots? structure consists of nano-sized multilayers of graphene oxide, nickel and platinum which provide different functionalities. The outer layer of graphene oxide captures lead on the surface, the inner layer of platinum function as the engine decomposing hydrogen peroxide fuel for self-propulsion, whilst the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead ten times more efficiently than non-mobile GOx-microbots, cleaning water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after chemical detachment of lead from the surface of GOx-microbots, the microbots can be reused. Finally, we demonstrate the magnetic control of the GOx-microbots inside a microfluidic system as a proof-of-concept for automatic microbots-based system to remove and recover heavy metals. Heavy metal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nano-systems and nanomaterials for fast and efficient removal of pollutants and heavy metals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer and removal of a heavy metal -lead-, and its subsequent recovery for recycling purposes. Microbots? structure consists of nano-sized multilayers of graphene oxide, nickel and platinum which provide different functionalities. The outer layer of graphene oxide captures lead on the surface, the inner layer of platinum function as the engine decomposing hydrogen peroxide fuel for self-propulsion, whilst the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead ten times more efficiently than non-mobile GOx-microbots, cleaning water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after chemical detachment of lead from the surface of GOx-microbots, the microbots can be reused. Finally, we demonstrate the magnetic control of the GOx-microbots inside a microfluidic system as a proof-of-concept for automatic microbots-based system to remove and recover heavy metals.


Parmar, J., Vilela, D., Pellicer, E., Esqué-de los Ojos, D., Sort, J., Sánchez, S., (2016). Reusable and long-lasting active microcleaners for heterogeneous water remediation Advanced Functional Materials 26, (23), 4152-4161

Self-powered micromachines are promising tools for future environmental remediation technology. Waste-water treatment and water reuse is an essential part of environmental sustainability. Herein, we present reusable Fe/Pt multi-functional active microcleaners that are capable of degrading organic pollutants (malachite green and 4-nitrophenol) by generated hydroxyl radicals via a Fenton-like reaction. Various different properties of microcleaners, such as the effect of their size, short-term storage, long-term storage, reusability, continuous swimming capability, surface composition, and mechanical properties, are studied. It is found that these microcleaners can continuously swim for more than 24 hours and can be stored more than 5 weeks during multiple cleaning cycles. The produced microcleaners can also be reused, which reduces the cost of the process. During the reuse cycles the outer iron surface of the Fe/Pt microcleaners generates the in-situ, heterogeneous Fenton catalyst and releases a low concentration of iron into the treated water, while the mechanical properties also appear to be improved due to both its surface composition and structural changes. The microcleaners are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), nanoindentation, and finite-element modeling (FEM).

Keywords: Catalysts, Heterogeneous catalysis, Microcleaners, Micromotors, Nanorobots, Wastewater treatment


Parmar, Jemish, Jang, Seungwook, Soler, Lluis, Kim, Dong-Pyo, Sánchez, Samuel, (2015). Nano-photocatalysts in microfluidics, energy conversion and environmental applications Lab on a Chip 15, 2352-2356

Extensive studies have been carried out on photocatalytic materials in recent years as photocatalytic reactions offer a promising solution for solar energy conversion and environmental remediation. Currently available commercial photocatalysts still lack efficiency and thus are economically not viable for replacing traditional sources of energy. This article focuses on recent developments in novel nano-photocatalyst materials to enhance photocatalytic activity. Recent reports on optofluidic systems, new synthesis of photocatalytic composite materials and motile photocatalysts are discussed in this article.


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