Photo-Responsive Graphene and Carbon Nanotubes to Control and Tackle Biological Systems

Abstract

Photo-responsive multifunctional nanomaterials are receiving considerable attention for biological applications because of their unique properties. The functionalization of the surface of carbon nanotubes (CNTs) and graphene, among other carbon based nanomaterials, with molecular switches that exhibit reversible transformations between two or more isomers in response to different kind of external stimuli, such as electromagnetic radiation, temperature and pH, has allowed the control of the optical and electrical properties of the nanomaterial. Light-controlled molecular switches, such as azobenzene and spiropyran, have attracted a lot of attention for nanomaterial's functionalization because of the remote modulation of their physicochemical properties using light stimulus. The enhanced properties of the hybrid materials obtained from the coupling of carbon based nanomaterials with light-responsive switches has enabled the fabrication of smart devices for various biological applications, including drug delivery, bioimaging and nanobiosensors. In this review, we highlight the properties of photo-responsive carbon nanomaterials obtained by the conjugation of CNTs and graphene with azobenzenes and spiropyrans molecules to investigate biological systems, devising possible future directions in the field.

Spiropyran-Based Drug Delivery Systems

“…Carbon nanomaterials (CNMs) are chemically stable, and their surfaces can be easily modified, allowing for robust control of their physicochemical properties and functions within the body—as such, they lend to many biological applications, especially in the case of photoresponsive CNMs ( Cardano et al, 2018 ). In particular, single-walled carbon nanotubes (SWNTs) and graphene show potential for their use in light-controlled DDSs, when modifying their surface with photochromic SP molecules ( Del Canto et al, 2012 ; Nahain et al, 2013 ).…”

Azobenzene isomerization in condensed matter: lessons for the design of efficient light-responsive soft-matter systems

“…A review of this method of photo control with a specific focus on microgels, DNA molecules, polymer brushes and colloidal particles can be found here. 157 Azobenzene derivatives have also been considered in many other mixed systems with substrates including graphene 158,159 and graphene oxide, 160,161 polyelectrolytes, 162,163 and metal surfaces. [164][165][166][167] Conveniently, some metal nanocrystal systems are well positioned for in situ monitoring using surface enhanced Raman spectroscopy (SERS).…”

Antimicrobial Activity of Nanomaterials: From Selection to Application

“…It has also tried to automate these techniques using fluorescent dyes that determine cell viability such as resazurin, SYTO9, and 4′,6-diamino-2-phenylindole (DAPI) but that tend to react with metal nanoparticles, which alters the results of in vitro susceptibility (Panic et al 2015;Magana et al 2018). Thus, by virtue of the above, attempts have been made to implement more sensitive and specific methods such as flow cytometry and real-time PCR, in order to more accurately quantify the microbial mass after it has been exposed, but some materials such as nanotubes and graphene can inhibit the reactions necessary to obtain a correct reading (Emerson et al 2017;Cossarizza et al 2017;Kralik and Ricchi 2017;Cardano et al 2018). So the major evaluation of nanomaterials antimicrobial activity using the CLSI and EUCAST protocols has been in the evaluation of nanotransporters of medications such as liposomes, micelles, and polymers (Álvarez-Paino et al 2017;Sedghizadeh et al 2017;Arévalo et al 2019;Martin-Serrano et al 2019).…”