Label-free detection of synthetic, full genomic length HIV-1 RNA at the few-copy level.

Oligonucleotide-functionalized graphene biosensors show immense promise for use as label-free point of care devices for detection of nucleic acid biomarkers at clinically relevant levels. Graphene-based nucleic acid sensors can be fabricated at low cost and have been shown to reach limits of detection in the attomolar range. Here we demonstrate devices functionalized with 22mer or 8omer DNA probes are capable of detecting full length genomic HIV-1 subtype B RNA, with a limit of detection below 1 aM in nuclease free water. We also show that these sensors are suitable for detection directly in Qiazol lysis reagent, again with a limit of detection below 1 aM for both 22mer and 8omer probes.

The C-terminus of the mu opioid receptor is critical in G-protein interaction as demonstrated by a novel graphene biosensor.

Several water-soluble variants of the human mu opioid receptor (wsMORs) have been designed and expressed, which enables the detection of opioids in the nM to pM range using biosensing platforms. The tools previously developed allowed us to investigate MOR and G-protein interactions in a lipid free system to demonstrate that the lipid bilayer might not be essential for the G-protein recognition and binding. In this study, we are able to investigate G-protein interactions with MOR by using graphene enabled technology, in a lipid free system, with a high sensitivity in a real time manner. A new wsMOR with the native C-terminus was designed, expressed and then immobilized on the surfaces of scalable graphene field effect transistor (GFET)-based biosensors, enabling the recording of wsMOR/G-protein interaction with an electronic readout. G-protein only interacts with the wsMOR in the presence of the native MOR C-terminus with a KA of 32.3±11.1 pM. The electronic readout of such interaction is highly reproducible with little variance across 50 devices in one biosensor array. For devices with receptors that do not have the native C-terminus, no significant electronic response was observed in the presence of G-protein, indicating an absence of interaction. These findings reveal that lipid environment is not essential for the G-protein interaction with MOR, however, the C-terminus of MOR is essential for G-protein recognition and high affinity binding. A system to detect MOR-G protein interaction is developed. wsMOR-G2_Cter provides a novel tool to investigate the role of C terminus in the signaling pathway.

Rapid Growth of Monolayer MoSe2 Films for Large-Area Electronics.

The large-scale growth of semiconducting thin films on insulating substrates enables batch fabrication of atomically thin electronic and optoelectronic devices and circuits without film transfer. Here an efficient method to achieve rapid growth of large-area monolayer MoSe2 films based on spin coating of Mo precursor and assisted by NaCl is reported. Uniform monolayer MoSe2 films up to a few inches in size are obtained within a short growth time of 5 min. The as-grown monolayer MoSe2 films are of high quality with large grain size (up to 120 µm). Arrays of field-effect transistors are fabricated from the MoSe2 films through a photolithographic process; the devices exhibit high carrier mobility of ≈27.6 cm2 V-1 s-1 and on/off ratios of ≈105. The findings provide insight into the batch production of uniform thin transition metal dichalcogenide films and promote their large-scale applications.

Study on the effect of food on the absorption of theophylline.

BACKGROUND: The pharmacokinetics of theophylline under fasting and normal meal have been widely studied, but that of Euphyllin Retard in Chinese subjects has not been reported. Since various food-induced absorption changes occur with sustained-release theophylline, it is of interest to study the food effect (especially Chinese food) on this drug product. METHODS: A total of 10 non-smoking healthy male volunteers were involved in the study with a 2-period crossover comparison. They were randomly divided into 2 groups. In the first phase study, group A took a single dose of 350 mg Euphyllin Retard (theophylline-ethylenediamine formulation, containing 255 anhydrous theophylline) under fasting condition. Group B took the same dose with breakfast. Blood samples were collected before and during the 36 hours following administration of the drug. For the second-phase study after 2 weeks, the group A acted as fasting group and group B as non-fasting group. The difference in the absorption of theophylline with fasting versus non-fasting administration was assessed using pharmacokinetic parameters derived from a serum theophylline concentration (STC) vs time curve. RESULTS: The means of maximum drug concentration (Cmax), unextrapolated area under the concentration vs time curve (AUC) from time 0 to 24 hours (AUCun), extrapolated AUC from time 0 to infinity (AUCex), and terminal elimination rate constant (Kel) were higher in the non-fasting group. The fasting group showed a more delayed time to maximum concentration (Tmax). The mean of half-life (T50%) was slightly higher in fasting group. In comparing each of the variables, no statistically significant differences were demonstrated between the 2 modes of administration except Cmax. CONCLUSION: Food increases the rate but not the extent of the absorption of Euphyllin Retard, and one should be aware of the possibility of unwanted side effects caused by high peak concentration. There were wide variations in serum drug levels among individuals, so serum theophylline level monitoring is necessary for an optimal effect. This study was performed in a limited number of normal healthy subjects and the same result is yet to be in asthmatic patients and a larger population of normal subjects.