Fabrication of a novel impedimetric biosensor for label free detection of DNA damage induced by doxorubicin.

In this work, a novel impedimetric biosensor has been fabricated for detection of DNA damage induced by doxorubicin (DX). Cytochrome P450 reductase (CPR) is required for electron transfer from nicotinamide adenine dinucleotide phosphate (NADPH) to cytochrome P450 (CP450) which causes DX to undergo a one-electron reduction of the p-quinone residue to form the semiquinone radical resulting in the generation of free hydroxyl radical which causes DNA damage. After modification of bare glassy carbon electrode (GCE) with multiwalled carbon nanotubes (MWCNTs) and chitosan (Ch), CPR and CP450 were co-immobilized onto the surface of Ch/MWCNTs/GCE by cross-linking CPR, CP450 and Ch through addition of glutaraldehyde. Then, the DNA was assembled onto the surface of CPRCP450/Ch/MWCNTs/GCE to fabricate the biosensor (DNA/CPRCP450/Ch/MWCNTs/GCE). Modifications applied to the bare GCE to fabricate the biosensor were characterized by CV, EIS and SEM. The DNA/CPRCP450/Ch/MWCNTs/GCE was treated in the damaging solution (DX + NADPH) which caused a significant DNA damage and the exposed DNA bases reduced the electrostatic repulsion of the negatively charged redox probe leading to Faradaic impedance changes. Performance of the biosensor for detection of DNA damage in the presence of Spinach extract was also examined and finally, an indirect impedimetric method was developed for determination of DX.

In vitro outlook of gold nanoparticles in photo-thermal therapy: a literature review.

Hyperthermia is an anti-cancer treatment in which the temperature of the malignant tumor is increased more than other adjacent normal tissues. Microwave, ultrasound, laser, and radiofrequency sources have been used for hyperthermia of cancerous tissues. In the past decade, near-infrared (NIR) laser for cancer therapy, known as photo-thermal therapy (PTT), was expanded in which the photo-sensitizer agent converts the light photon energy to heat. The heat following PTT can destroy cancer cells. There are some photo-sensitizer agents which have been used for PTT; however, owing to recent advances in nanotechnology, noble metal nanoparticles like gold (Au) nanoparticles (GNPs) have been used successfully in PTT. GNPs have some desirable specifications, including simple and controlled synthesis, small size, high level of biocompatibility, and surface plasmon resonance (SPR). The SPR effect of the GNPs increases the radiative properties like absorption and scattering; therefore, they can be used in PTT. In this article, we reviewed recent in vitro studies of PTT using GNPs in literature. At first, we focus on the physical properties of GNPs, their interaction with infrared radiation, and physical parameters governing the interaction of infrared radiation with the GNPs. Then, we review the passive and active targeting of GNPs using the different coating to induce the thermal damage in cancer cells using low-level laser PPT. The GNPs' cellular internalization into cancer cells is a challenge which is consequently considered. In this review, we also summarize the results of synergistic cancer therapy studies on the combination of radiation therapy as a routine cancer treatment and PTT: in which significant improvement occurs in treatment efficacy.