Browsing by Author "Cheng, Wei-Da"

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Design and optimization of a nanoprobe comprising amphiphilic chitosan colloids and Au-nanorods: Sensitive detection of human serum albumin in simulated urine
(2016-12-30)
Jean, Ren-Der
;
Larsson, Mikael
;
Cheng, Wei-Da
;
Hsu, Yu-Yuan
;
Bow, Jong-Shing
Metallic nanoparticles have been utilized as analytical tools to detect a wide range of organic analytes. In most reports, gold (Au)-based nanosensors have been modified with ligands to introduce selectivity towards a specific target molecule. However, in a recent study a new concept was presented where bare Au-nanorods on self-assembled carboxymethyl-hexanoyl chitosan (CHC) nanocarriers achieved sensitive and selective detection of human serum albumin (HSA) after manipulation of the solution pH. Here this concept was further advanced through optimization of the ratio between Au-nanorods and CHC nanocarriers to create a nanotechnology-based sensor (termed CHC-AuNR nanoprobe) with an outstanding lower detection limit (LDL) for HSA. The CHC-AuNR nanoprobe was evaluated in simulated urine solution and a LDL as low as 1.5 pM was achieved at an estimated AUNR/CHC ratio of 2. Elemental mapping and protein adsorption kinetics over three orders of magnitude in HSA concentration confirmed accumulation of HSA on the nanorods and revealed the adsorption to be completed within 15 min for all investigated concentrations. The results suggest that the CHC-AuNR nanoprobe has potential to be utilized for cost-effective detection of analytes in complex liquids. (C) 2016 Elsevier B.V. All rights reserved.
Highly electrostatically-induced detection selectivity and sensitivity for a colloidal biosensor made of chitosan nanoparticle decorated with a few bare-surfaced gold nanorods
(2014-02-15)
Jean, Ren-Der
;
Cheng, Wei-Da
;
Hsiao, Meng-Hsuan
;
Chou, Fu-Hsuan
;
Bow, Jong-Shing
Metallic nanoparticles have been utilized as an analytical tool to detecting a wide variety of organic analytes. Among them, gold nanoparticles demonstrating outstanding surface plasmonic resonance property have been well recognized and received wide attention for plasmon-based sensing applications. However, in literature, gold-based nanosensor has to be integrated with specific "ligand" molecule in order to gain molecular recognition ability. However, "ligand" molecules, included proteins, peptides, nucleic acids, etc. are expensive and vulnerable to environmental change, in the meantime, anchoring procedure of the "ligand" molecules to gold surface may be cost-ineffective and endangered to the ligand's activity, making a final analytic probe less reliable and risk in production capability. Here, we develop a new approach by designing a colloid-type sensor using a few "bare" Au nanorods deposited on the surface of a colloidal chitosan carrier. By tuning the solution pH, the resulting colloidal nanoprobe is capable of detecting proteins, i.e., human serum albumin and lysozyme, with high specificity and sensitivity. This new approach allows a new type of the molecular probes to be well manipulated to monitor important biomolecules for medical detection, diagnosis, and bioengineering applications. (C) 2013 Elsevier B.V. All rights reserved.