Near-infrared photoluminescence biosensing platform with gold nanorods-over-gallium arsenide nanohorn array

On-chip high-sensitivity photonic temperature sensor based on a GaAs microresonator

We demonstrate an on-chip high-sensitivity photonic temperature sensor based on a GaAs microdisk resonator. Based on the large thermo-optic coefficient of GaAs, a temperature sensitivity of 0.142 nm/K with a measurement resolution of 10 mK and low input optical power of only 0.5 µW was achieved. It exhibits great potential for chip-scale biological research and integrated photonic signal processing.

Vertical nanowire array-based biosensors: device design strategies and biomedical applications

Biosensors have been extensively studied in the areas of biology, electronics, chemistry, biotechnology, medicine, and various engineering fields. The interdisciplinarity creates an ideal platform for scientists to analyze biological species and chemical materials in a direct, efficient, and sensitive manner; this is expected to revolutionize the life sciences, basic medicine, and the healthcare industry. To carry out high-performance biosensing, nanoprobes - with specific nanoscale properties - have been proposed for ultrasensitive and in situ monitoring/detection of tracer biomolecules, cellular behavior, cellular microenvironments, and electrophysiological activity. Here, we review the development of vertical nanowire (VNW) array-based devices for the effective collection of biomedical information at the molecular level, extracellular level, and intracellular level. In particular, we summarize VNW-based technologies in the aspects of detecting biochemical information, cellular information, and bioelectrical information, all of which facilitate the understanding of fundamental biology and development of therapeutic techniques. Finally, we present a conclusion and prospects for the development of VNW platforms in practical biomedical applications, and we identify the challenges and opportunities for VNW-based biosensor systems in future biological research.

Analysis of lead forms and transition in agricultural soil by nano-fluorescence method

The physicochemical properties of gold nanorods were used to develop many methods and techniques of detecting heavy metals recently. In this paper, the feasibility of gold nanorods was studied to detect metal lead in agricultural soil. The effects of soil properties on the form change of lead in soil were explored by gold nanorod detection technology. The results showed that the humic acid significantly increased Pb mobility and ion state exchanging. It also increased the lead content of organic bound state and Fe-Mn oxides state. And the detection process by gold nanorods proved to be a more simple and convenient method.

Optical tuning of plasmon-enhanced photoluminescence

Photoluminescence (PL) can be enhanced and tuned with the assistance of surface plasmons. Traditional methods of generating tunable fluorophores are either of low efficiency or complicated with poor controllability. Here, we propose the optical tuning and enhancement of PL by modifying the plasmon modes, which shows unique advantages of generality, simplicity, and on-demand controllability. We adopted gold nanoparticles on a mirror as the plasmonic resonator, and responsive polymers as the spacers as well as the emitters in the nanogaps. By controlling the coating thickness of polymers, we can achieve tunable plasmon resonances as well as PL peaks with an enhancement factor up to ∼7000. Furthermore, we show the optical tuning of the plasmon resonances via laser irradiation which modifies the nanogaps. Thus, the PL peaks of the polymers shift accordingly with plasmon resonances. This tuning mechanism is based on plasmon-enhanced PL, which selectively enhances PL signals at different wavelengths. Such a plasmon-assisted PL selection by the optical tuning method provides new opportunities for photonic devices with applications of multiplex sensing and full colour displays.

One-step synthesis of nitrogen, sulfur co-doped carbon nanodots and application for Fe3+ detection

Carbon nanodots (CDs) are novel forms of zero-dimensional carbonaceous nanomaterials, which have attracted the attention of researchers.