On-Demand Release of Drug from Magnetic Nanoparticle-Loaded Alginate Beads.

Targeted delivery and controlled release of drugs has been considered to be an important therapeutic approach since it could allow a better treatment efficiency and less side effects. In this research, magnetite Fe3O4 nanoparticles were successfully synthesized via the coprecipitation method and then loaded in alginate beads with berberine as a drug model for drug release application. Various factors such as pH values of the suspended environment and surface modifications of the drug carrier could be exploited to adjust the amount of drug release. More importantly, the amount of drug release could be effectively controlled by an on-off switching operation of a static magnetic field.

Quantitative electrophysiological monitoring of anti-histamine drug effects on live cells via reusable sensor platforms.

We demonstrated the quantitative electrophysiological monitoring of histamine and anti-histamine drug effects on live cells via reusable sensor platforms based on carbon nanotube transistors. This method enabled us to monitor the real-time electrophysiological responses of a single HeLa cell to histamine with different concentrations. The measured electrophysiological responses were attributed to the activity of histamine type 1 receptors on a HeLa cell membrane by histamine. Furthermore, the effects of anti-histamine drugs such as cetirizine or chlorphenamine on the electrophysiological activities of HeLa cells were also evaluated quantitatively. Significantly, we utilized only a single device to monitor the responses of multiple HeLa cells to each drug, which allowed us to quantitatively analyze the antihistamine drug effects on live cells without errors from the device-to-device variation in device characteristics. Such quantitative evaluation capability of our method would promise versatile applications such as drug screening and nanoscale bio sensor researches.

Reusable floating-electrode sensor for the quantitative electrophysiological monitoring of a nonadherent cell.

We report a reusable floating-electrode sensor based on aligned semiconducting single-walled carbon nanotubes for the quantitative monitoring of the electrophysiological responses from a nonadherent cell. This method allowed us to monitor and distinguish the real-time responses from normal and small-cell lung cancer (SCLC) cells to the addition of nicotine. The difference was attributed to the overexpressed nicotinic acetylcholine receptors (nAChRs) in the SCLC cells. The sensor was also utilized to monitor the effect of various drugs on the cells. The treatment with inhibitors such as genistin or daidzein was found to reduce Ca(2+) influx in SCLC cells. Moreover, tamoxifen, though known as the antiestrogen compound, was found to only partly block the binding of daidzein to nAChRs. Significantly, the activities of multiple individual cells could be measured repeatedly using a single sensor device, enabling statistically meaningful measurements without errors from the device-to-device variations of the sensor characteristics. This capability of the quantitative monitoring of nonadherent cells should be a major breakthrough for electrophysiology research and various biomedical applications such as drug screening and therapeutic monitoring.

HPV 9G DNAChip: Based on the 9G DNAChip technology.

The novel HPV 9G DNAChips were developed for the detection and discrimination of the HPV genotypes in the clinical samples. The HPV 9G DNAChip established high SBR of 50-70 and 100% target-specific hybridization after 30min hybridization and 2×2min washing at 25°C. We compared the genotyping results of the 959 HPV positive and 82 HPV negative clinical samples by the HPV 9G DNAChip and the sequencing; the results are in 100% agreement. The HPV 9G DNAChip efficiently discriminate 19 HPV genotypes in the 959 HPV positive clinical samples. The results of HPV 9G DNAChip were 100% identical with the sequencing analysis in the detection and discrimination of HPV genotypes in the HPV negative clinical samples. The high SBR, 100% target-specific hybridization, and 25°C hybridization and washing makes the HPV 9G DNAChip a promising diagnostic tool for the accurate HPV genotyping.

HPAI 9G DNAChip: discrimination of highly pathogenic influenza virus genes.

The HPAI 9G DNAChip discriminates the single nucleotide polymorphism of H5N1, H5N1 (K), and H5N3 in a 60:1 ratio. It allows the simultaneous detection of highly pathogenic avian influenza viruses with a signal to background ratio of 200 and 100% target-specific hybridization in 30 min at 25 °C.

HPV 9G DNA chip: 100% clinical sensitivity and specificity.

We describe a novel HPV 9G DNA chip test for the accurate and reliable genotyping of human papillomavirus (HPV). The HPV 9G DNA chip test established its efficiency in terms of a signal-to-background ratio (SBR) of 200, which is 50 times superior to commercial HPV DNA chips, and 100% target-specific hybridization at 25°C. We compared the genotyping results for the 439 clinical samples by the HPV 9G DNA chip test with the sequencing results for the MY11/GP6+ (M2) primer set-mediated PCR products. The discrimination of HPV genotypes in the 151 HPV-positive clinical samples by the HPV 9G DNA chip test were 100% identical with the sequencing analysis. The clinical sensitivities of HPV genotyping by the HPV 9G DNA chip test and a commercial HPV DNA chip test were 100% and 88%, respectively. However, the clinical specificities of HPV genotyping by the HPV 9G DNA chip test and the commercial HPV DNA chip test were 100% and 94%, respectively. The 100% clinical sensitivity and specificity of the HPV 9G DNA chip test make it a promising diagnostic tool for HPV genotyping.

A generalized probe selection method for DNA chips.

The flaws in the present probe selection methods restrained the development of the DNA chip technology and its applications. The presented generalized probe selection method for the DNA chips elaborates the length of the probe, the melting temperatures, the specificity of the probe, and the position where the probe may bind to the targets.

Characterization of the mixed self-assembled monolayer at the molecular scale.

The mixed SAM obtained by the self-assembly of the monothiolated calix[4]crown-5 receptor 1 and the subsequent addition of the thiolated alkylferrocene guest 3 was characterized at the molecular scale by the favorable receptor-guest interactions by using cyclic voltammetry (CV).

9G DNAChip: a platform for the efficient detection of proteins.

According to the proposed DAGON method, the CRP and PSA antigens with the concentrations of 1 pg ml(-1) to 10 pg ml(-1) range can be easily differentiated in the buffer matrix. Moreover, it is for the first time that the multiple antigens with the concentrations of 1 pg ml(-1) and 0.1 pg ml(-1) can be detected in the mixture of the proteins without an amplification technique.

9G DNAChip: microarray based on the multiple interactions of 9 consecutive guanines.

We introduce the phenomenon of molecular recognition to immobilize oligonucleotides on AMCA slides for the production of 9G DNAChips. Facile and efficient method for the immobilization of the oligonucleotides appended with consecutive nine guanine bases is described. The 9G DNAChips shows more than 90% hybridization efficiency at 25 °C in 30 min.