IN THIS STUDY, FE3O4 MAGNETIC NANOPARTICLES (MNPS) WERE PREPARED BY CO-PRECIPITATION METHOD AND THIOL-FUNCTIONALIZED WITH (3-MERCAPTOPROPYL) TRIMETHOXYSILANE. THE SIZE AND STRUCTURE OF MNPS AND THIOL-FUNCTIONALIZED ONES WERE CHARACTERIZED BY SCANNING ELECTRON MICROSCOPE (SEM), BET SURFACE AREA AND FTIR. THE LOADING CAPACITY OF FUNCTIONALIZED MAGNETIC NANOPARTICLES AND ACTIVITY OF FREE AND IMMOBILIZED LIPASE WERE DETERMINED. UNDER EXPERIMENTAL CONDITIONS (T=25OC, PH=7), 82.1% OF THE AVAILABLE LIPASE WAS IMMOBILIZED ON THE FUNCTIONALIZED MNPS RESULTING A LIPASE LOADING CAPACITY OF 360 MG/ (G FUNCTIONALIZED MNPS). ENZYME ASSAYS REVEALED THAT LIPASE IMMOBILIZED ON THIOL-FUNCTIONALIZED MAGNETIC NANOPARTICLE DISPLAYED ENHANCED THE LIPASE THERMAL STABILITY IN COMPARISON WITH FREE LIPASE.

IN RECENT YEARS, THE INTEREST FOR DNA-BASED DIAGNOSTIC TESTS HAS BEEN GROWING. THE DEVELOPMENT OF SYSTEMS ALLOWING DNA DETECTION IS MOTIVATED BY APPLICATIONS IN MANY FIELDS: DNA DIAGNOSTICS, GENE ANALYSIS, FAST DETECTION OF BIOLOGICAL WARFARE AGENTS, AND FORENSIC APPLICATIONS.DETECTION OF GENETIC MUTATIONS AT THE MOLECULAR LEVEL OPENS UP THE POSSIBILITY OF PERFORMING RELIABLE DIAGNOSTICS EVEN BEFORE ANY SYMPTOM OF A DISEASE APPEARS. OPTICAL [1], ELECTROCHEMICAL [2], AND MICRO-GRAVIMETRICAL [3] DNA TRANSDUCTIONS HAVE BEEN WIDELY STUDIED. AN IN SITU METHOD FOR DIRECT ATTACHMENT OF 4-NITROBENZENEDIAZONIUM ONTO THE SURFACE OF MAGNETITE NANOPARTICLES TO DEVELOP AN EFFICIENT GUIDE FOR CONSTRUCTION OF DNA ELECTROCHEMICAL BIOSENSOR WAS PROPOSED. FOR FUNCTIONALIZATION OF MAGNETIC NANOPARTICLES, FIRSTLY AZO SALT OF NITROANILINE (4-NITROBENZENEDIAZONIUM) WAS PREPARED AND WAS REACTED DIRECTLY WITH MAGNETITE NANOPARTICLES IN BASIC SOLUTION FOLLOWED BY ELECTROCHEMICAL REDUCTION OF THE TERMINAL NITRO GROUP TO AMINE. THIS NH2 GROUP CAN INTERACT WITH AN ACTIVATED PHOSPHATE GROUP OF NON-LABELED SS-DNA RELATED TO HEPATITIS B VIRUS. ACTIVATED NON-LABELED SS-DNA WAS PREPARED USINGN - (3 DIMETHYLAMINOPROPYL) -N -ETHYL-CARBODIIMIDE HYDROCHLORIDE (EDC) AND N -HYDROXY-SUCCINIMIDE (NHS). THE DNA HYBRIDIZATION EVENTS WERE MONITORED BY DIFFERENTIAL PULSE VOLTAMMETRY (DPV) MEASUREMENT OF THE INTERCALATED METHYLENE BLUE (MB) AS A WELL-KNOWN ELECTROCHEMICAL INDICATOR. UNDER OPTIMAL CONDITIONS, THE REDUCTION PEAK CURRENTS WERE LINEARLY DECREASED WITH INCREASING THE CONCENTRATION OF HBV TARGET DNA FROM 7.8 (±0.2) × 10-13 MOL L-1 TO 8.8 (±0.3) × 10-9 MOL L-1 WITH A DETECTION LIMIT OF 3.3 (±0.2) × 10-13 MOL L-1. THIS DNA BIOSENSOR EXHIBITED EXCELLENT SELECTIVITY, REPRODUCIBILITY, AND STABILITY IN THE HBV DNA HYBRIDIZATION ASSAY.

CARBON NANOTUBES HAVE NUMEROUS POTENTIAL APPLICATIONS DUE TO THEIR OUTSTANDING STRUCTURAL, MECHANICAL, AND ELECTRICAL PROPERTIES. Functionalizing CARBON NANOTUBES ARE REQUIRED AND CRITICAL FOR CARRYING THESE APPLICATIONS. ONE OF THE MOST WELL-DEVELOPED APPROACHES FOR Functionalizing NANOTUBES INVOLVES INTRODUCING CARBOXYLIC GROUPS ONTO THEIR SURFACES VIA AN ACID TREATMENT [1, 2]...

CALIXARENES ARE A FAMILY OF SYNTHETIC RECEPTORS THAT THEIR ABILITY IN Functionalizing PROVIDES SEVERAL APPLICATION [1]. IN RECENT YEARS CALIX [4] ARENES ARE USED AS DNA INTERCALATORS [2]. ACRIDINE DERIVATIVES ARE ONE OF THE OLDEST AND MOST SUCCESSFUL CLASSES OF BIOACTIVE AGENTS AND WIDELY UTILIZED AS ANTIMALARIAL, ANTIPROTOZOAL, ANTIBACTERIAL AND ANTICANCER DRUGS [3]....