silicon and HIV-Infections

A hydrogenated amorphous silicon (a-Si:H) photosensor was explored for the quantitative detection of a HIV-1 virion infectivity factor (Vif) at a detection limit in the single nanomolar range. The a-Si:H photosensor was coupled with a microfluidic channel that was functionalized with a recombinant single chain variable fragment antibody. The biosensor selectively recognizes HIV-1 Vif from human cell extracts.

Topics: HEK293 Cells; HIV Infections; HIV-1; Humans; Microfluidic Analytical Techniques; Optics and Photonics; Silicon; vif Gene Products, Human Immunodeficiency Virus

Intravaginal delivery of microbicide combinations is a promising approach for the prevention of sexually transmitted infections, but requires a method of providing simultaneous, independent release of multiple agents into the vaginal compartment. A novel intravaginal ring (IVR) platform has been developed for simultaneous delivery of the reverse-transcriptase inhibitor tenofovir (TFV) and the guanosine analogue antiviral acyclovir (ACV) with independent control of release rate for each drug. The IVR is based on a pod design, with up to 10 individual polymer-coated drug cores embedded in the ring releasing through preformed delivery channels. The release rate from each pod is controlled independently of the others by the drug properties, polymer coating, and size and number of delivery channels. Pseudo-zero-order in vitro release of TFV (144 ± 10 µg day) and ACV (120 ± 19 µg day⁻¹) from an IVR containing both drugs was sustained for 28 days. The mechanical properties of the pod IVR were evaluated and compared with the commercially available Estring® (Pfizer, NY, NY). The pod-IVR design enables the vaginal delivery of multiple microbicides with differing physicochemical properties, and is an attractive approach for the sustained intravaginal delivery of relatively hydrophilic drugs that are difficult to deliver using conventional matrix IVR technology.

Topics: Acyclovir; Adenine; Administration, Intravaginal; Animals; Antiviral Agents; Delayed-Action Preparations; Drug Delivery Systems; Equipment Design; Female; HIV; HIV Infections; Humans; Organophosphonates; Reverse Transcriptase Inhibitors; Silicon; Tenofovir; Tensile Strength

IUDs are rigid and heavy thus irritating the endometrium. Their design accounts for many side effects and encourages pelvic infections. IUDs may even facilitate transmission of HIV. Since some health professionals and patients consider some IUDs to be harmful or unacceptable, researchers have worked on developing a newly designed IUD which meets the criteria for and ideal IUD. Some criteria include soft and flexible in nature and inside the uterus, safe, no migration, and light in weight. Taiwanese researchers have developed such an IUD. The silicone skeleton of the Wang SS (soft and safe) Copper 380 and 300 IUDs is bow-shaped with each arm of the bow tapering off from the middle and ending with a small rounded knob. Copper wire (0.31 mm x 380 sq mm or 0.31 mm x 300 sq mm) coils around the holeless vertical stem (3 cm). The monofilament nylon string is fixed in the middle of the stem by an enlarged top. Researchers designed the Wang SS Cu 300 for nulliparous women and the Wang SS Cu 380 for multiparous women. If physicians use a Wang IUD from a sterilized package, they can insert it without wearing sterile gloves. They need to clean the cervix. They must use a single tooth tenaculum to stabilize the uterus and to straighten the uterine axis. After placing the Wang IUD in the inserter, adjusting the flange, and putting the plunger on the inserter, they need to safely introduce the inserter into the uterine cavity to the point where the inserter touches the fundus or the flange touches the cervix. They then must push the plunger to insert the IUD. Insertion should be done immediately after menstruation. Clinicians need to conduct clinical trials to test the safety and effectiveness of the Wang Ss Cu IUDs.

Topics: Asia; Asia, Eastern; Birth Rate; Chemical Phenomena; Chemistry; China; Contraception; Demography; Developing Countries; Disease; Economics; Family Planning Services; Fertility; HIV Infections; Infections; Inorganic Chemicals; Intrauterine Devices; Intrauterine Devices, Copper; Nylons; Parity; Pelvic Inflammatory Disease; Polyethylene; Polymers; Population; Population Dynamics; Research; Silicon; Silicones; Taiwan; Technology; Therapeutics; Virus Diseases

A silicon-based device, dubbed a microphysiometer, can be used to detect and monitor the response of cells to a variety of chemical substances, especially ligands for specific plasma membrane receptors. The microphysiometer measures the rate of proton excretion from 10(4) to 10(6) cells. This article gives an overview of experiments currently being carried out with this instrument with emphasis on receptors with seven transmembrane helices and tyrosine kinase receptors. As a scientific instrument, the microphysiometer can be thought of as serving two distinct functions. In terms of detecting specific molecules, selected biological cells in this instrument serve as detectors and amplifiers. The microphysiometer can also investigate cell function and biochemistry. A major application of this instrument may prove to be screening for new receptor ligands. In this respect, the microphysiometer appears to offer significant advantages over other techniques.

Topics: Animals; Biotechnology; Cell Physiological Phenomena; Cells, Cultured; Culture Media; HIV Infections; Humans; Hydrogen-Ion Concentration; In Vitro Techniques; Potentiometry; Receptors, Cell Surface; Silicon