High sensitive detection of presenilin-1 point mutation based on electrochemilumi-nescence

Electrochemiluminescence (ECL) is a high- sensitive detection method with broad biological applications. Ruthenium (Ⅱ) tris (bipyridyl) 2+3(Ru(bpy)) and tripro-pylamine (TPA) are most commomly used combination of the reactive species in ECL. The redox of 2+3Ru(bpy) with excess TPA at the surface of an electrode produces a highly efficient and stable light emission due to a rapid cycle of the reactions. This rapid, highly sensitive and accurate method has been applied to gene quantification. In this work, an ECL detection system is designed and applied in detection of presenilin-1 (PS-1) gene mutation. The results show that given the same polymerase chain reaction (PCR) cycle num-ber, the ECL intensities from the digested and the undigested wild-type samples are nearly identical, but the difference in ECL intensities between the digested and the undigested mutant samples is distinctive. This detection technology connects PCR with ECL and allows a reliable discrimination between the wild-type and the mutant genes.

Polyrotaxane-based triblock copolymers synthesized via ATRP of N-isopropylacrylamide initiated from the terminals of polypseudorotaxane of Br end-capped pluronic 17R4 and β-cyclodextrins

Thermo-responsive polyrotaxane （PR）-based triblock copolymers were synthesized via the atom transfer radical polymeriza- tion （ATRP） of N-isopropylacrylamide initiated with self-assemblies made from a distal 2-bromoisobutyryl end-capped Plu- ronic 17R4 （PPOI4-PEG24-PPOI4） with a varying amount of β-cyclodextrins （β-CDs） in the presence of Cu（I）C1/PMDETA at 25 ~C in aqueous solution. The molecular structure was characterized by means of ~H NMR, FTIR, WXRD, GPC, TGA and DSC analyses. About half of [3-CDs are still entrapped on the Pluronic 17R4 chain while the number of incorporated NIPAAm monomers is nearly a double feed value in the resulting copolymers. The aggregate morphologies in aqueous solution were evidenced by TEM observations. A two-step thermo-responsive transition arising from a combination of a polypseudorotaxane middle block with poly（N-isopropylacrylamide） flanking blocks was also demonstrated by turbidity measurements. Given their thermo-responsive behavior in aqueous solution, these PR-based triblock copolymers show the potential to be used as smart materials for the controlled drug delivery systems, biosensors, and the like.