Epigenetically modified nucleobases (5hmc, 5fc, and 5caC) interaction with boron and nitrogen doped porous graphene (B/N-pGr) as promising materials for biosensing application: A density functional theory calculations

In this present work, porous graphene (pGr), boron (B-pGr), and nitrogen (N-pGr) doped porous sheets are explored as a bio-sensor device for sensing modified nucleobases (MBs) in cancer therapy using density functional theory (DFT). The obtained geometrical, energetic and electronic properties revealed that the B-pGr is highly reactive and it adsorbs MBs better than the pGr and N-pGr, because B atom holds empty p-orbitals which easily interact with partially filled p-orbital of N and O atom. Thus, the adsorption energies of 5hmc, 5caC, and 5fc on B-pGr are high rather than the pGr and N-pGr. The corresponding adsorption energies are -96.074, -77.0, and -60.721 kcal/mol for 5hmc, 5caC, and 5fc respectively. The positive signature of ΔN values (0.005 eV, 0.076 eV, and 0.047 in MBs on pGr and 0.171 eV, 0.252 eV and 0.205 eV in MBs on N-pGr) are obtained at MBs on pGr and N-pGr complex. The negative ΔN values (-0.141 eV, -0.032 eV, and -0.061 eV in MBs on B-pGr) are obtained at MBs of B-pGr. The calculated absorption values shows that the B-pGr is strongly adsorbed MBs at 342 nm. The obtained results exhibit that the B-pGr sheet retains significant therapeutic potential as a bio-sensing application for cancer therapy.

In situ H2O2 generation with gold nanoflowers as the coreactant accelerator for enzyme-free electrochemiluminescent immunosensing

In traditional electrochemiluminescence (ECL) analysis, gold nanomaterials are commonly used as a tool for signal amplification and linking antibodies due to their good electrical conductivity and biocompatibility. Here, we found that multitipped gold nanoparticles-gold nanoflowers (AuNFs) as coreactant accelerator have good catalytic activity for the reduction of dissolved oxygen (O₂) to hydrogen peroxide (H₂O₂) using tris (hydroxymethyl) aminomethane (Tris) as electron donor. Based on this, a new enzyme-free and label-free ECL immunosensor have been constructed for the detection of α-fetoprotein (AFP). In this system, due to the unique geometric and spatial effects of AuNFs, the dissolved O₂ as endogenous coreactant was catalyzed by AuNFs to produce H₂O₂ using Tris as an electron donor. The in situ generated H₂O₂ can more efficiently produce various electrogenerated reactive oxygen species (ROSs) as the important intermediates on the electrode surface. Then, oxidation of luminol reacts with ROSs significantly amplifies the luminol ECL signal. Under optimal experimental conditions, the proposed ECL immunosensor was able to detect the AFP concentration from 0.01 to 100 ng mL^-1, with a low detection limit of 3.4 pg mL^-1 (S/N = 3). In addition, the prepared ITO-based sensor is similar to a micro-test chip and convenient to use, thus making it suitable for clinical use as a disposable device in point-of-care tests (POCTs).

Theoretical Studies of Oxygen Reactivity of Free-Standing and Supported Boron-Doped Graphene

Graphene inertness towards chemical reactivity can be considered as an accepted postulate by the research community. This limit has been recently overcome by chemically and physically modifying graphene through non-metal doping or interfacing with acceptor/donor materials (metals or semiconductors). As a result, outstanding performances as catalytic, electrocatalytic, and photocatalytic material have been observed. In this critical Review we report computational work performed, by our group, on the reactivity of free-standing, metal- and semiconductor-supported B-doped graphene towards oxygen, which is at the basis of extremely important energy-related chemical processes, such as the oxygen reduction reaction. It appears that a combination of doping and interfacing approaches for the activation of graphene can open unconventional and unprecedented reaction paths, thus boosting the potential of modified graphene in many chemical applications.

Substitutional doping of carbon nanotubes with heteroatoms and their chemical applications

The electronic properties of carbon nanotubes (CNTs) can be tuned by substitutional doping with heteroatoms (mainly B and N) to expand the applications of CNTs. Based on the comprehensive understanding of the substitutional doping of CNTs, it should be possible to deliberately design doped CNTs for specific purposes. Thus, relevant experimental and theoretical works are reviewed herein in an attempt to correlate the synthetic methods, electronic properties, and applications of heteroatom-doped CNTs. The distribution and arrangement of heteroatoms in the graphitic lattice of CNTs can be modulated through the choice of synthetic conditions, which would further lead to different electronic properties of CNTs for their chemical applications.