title: Preparation of high-performance water-soluble quantum dots for biorecognition through fluorescence resonance energy transfer.
abstract: An improved method for the synthesis of high-performance and water-soluble quantum dots (QDs) involving the encapsulation of mercaptosuccinic acid coated QDs (MSA-QDs) with poly(diallyldimethylammonium chloride) (PDDA) followed by their direct photoactivation with fluorescent radiation near 295 K to yield PDDA-coated QDs (PDDA-QDs) has been demonstrated. The quantum yield (QY) of the PDDA-QDs was significantly improved from 0.6 (QY of MSA-QDs) to 48%. By using this synthetic strategy, highly photoluminescent PDDA-QDs of varied size were readily prepared. The surface properties of PDDA-QDs and MSA-QDs were extensively characterized. The highly luminescent and positively charged PDDA-QDs serve as a useful and convenient tool for protein adsorption. With a Δ(5)-3-ketosteroid isomerase adsorbed PDDA-QD complex, the biorecognition of steroids was demonstrated through the application of fluorescent resonance energy transfer.
authors.affiliation: Nanotechnology Research Center, Nano-Instrumentation and Application Division, Industrial Technology Research Institute, 195, Sec. 4, Chung Hsing Rd., Chutung, Hsinchu, Taiwan 31040, ROC.
authors.forename: Chin-Ping
authors.initials: CP
authors.lastname: Huang
authors.forename: Cheng-Fu
authors.initials: CF
authors.lastname: Chao
authors.forename: Mo-Yuan
authors.initials: MY
authors.lastname: Shen
authors.forename: Teng-Ming
authors.initials: TM
authors.lastname: Chen
authors.forename: Yaw-Kuen
authors.initials: YK
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D004800:Enzymes, Immobilized / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D049408:Luminescent Agents / Q000737:chemistry*; D011095:Polyethylenes / Q000737:chemistry; D045663:Quantum Dots; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013251:Steroid Isomerases / Q000378:metabolism; D013256:Steroids / Q000032:analysis*; D013870:Thiomalates / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D049408:Luminescent Agents; D011095:Polyethylenes; D000644:Quaternary Ammonium Compounds; D013256:Steroids; D013870:Thiomalates; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; C046062:2-thiomalic acid; D013251:Steroid Isomerases; C022660:steroid delta-isomerase