Liquid crystal elastomer foams with elastic properties specifically engineered as biodegradable brain tissue scaffolds.

Tissue regeneration requires 3-dimensional (3D) smart materials as scaffolds to promote transport of nutrients. To mimic mechanical properties of extracellular matrices, biocompatible polymers have been widely studied and a diverse range of 3D scaffolds have been produced. We propose the use of responsive polymeric materials to create dynamic substrates for cell culture, which goes beyond designing only a physical static 3D scaffold. Here, we demonstrated that lactone- and lactide-based star block-copolymers (SBCs), where a liquid crystal (LC) moiety has been attached as a side-group, can be crosslinked to obtain Liquid Crystal Elastomers (LCEs) with a porous architecture using a salt-leaching method to promote cell infiltration. The obtained SmA LCE-based fully interconnected-porous foams exhibit a Young modulus of 0.23 ± 0.07 MPa and a biodegradability rate of around 20% after 15 weeks both of which are optimized to mimic native environments. We present cell culture results showing growth and proliferation of neurons on the scaffold after four weeks. This research provides a new platform to analyse LCE scaffold-cell interactions where the presence of liquid crystal moieties promotes cell alignment paving the way for a stimulated brain-like tissue.

Microcapsule-gel formulation of promethazine HCl for controlled nasal delivery: a motion sickness medication.

The current method of choice for astronauts to treat space motion sickness is an intra-muscular injection of promethazine hydrochloride (PMZ HCl) which is invasive and causes considerable local irritation and discomfort at the site of injection. Intra-nasal delivery is considered a feasible alternative route for administration of medications to treat space motion sickness. The purpose of this research is to develop a PMZ HCl formulation that can be administered intra-nasally without irritation (i.e. leukocyte infiltration) in the nasal epithelium when dosed at PMZ HCl concentrations greater than the cytotoxic limit. The biocompatibility of PMZ HCl was tested in vitro and was shown to be cytotoxic at concentrations greater than 10(-5) molar regardless of pH. A controlled-release microencapsulated dosage formulation was developed using spinning disk atomization and release rates for the PMZ HCl microcapsules were determined in phosphate buffered saline. An animal study was conducted to determine the irritation response of rat nasal mucosa when dosed with encapsulated and non-encapsulated PMZ HCl.

Mucosal delivery of cytotoxic therapeutic agents: response of rat nasal mucosa to microencapsulated ethopropazine HCl enantiomer.

Use of microencapsulation technology in combination with absorption enhancers eliminated epithelium irritation and necrosis commonly associated with nasal delivery of cytotoxic therapeutic agents. Phenothiazines, such as ethopropazine (ETZ), promethazine, trimeprazine and propiomazine have been used for the treatment of allergenic conditions, motion sickness, nausea, Parkinson's disease, Prion disease and as a sedative for psychiatric disorders. The enantiomers of commercially available racemic phenothiazines were isolated and purified using classical diastereomeric salt techniques. The racemate and the enantiomers of ETZ were tested in vitro for their cellular toxicity using lung fibroblast cells. Each enantiomer was shown to be cytotoxic at concentrations greater than 10(-5) molar. The ETZ enantiomers were encapsulated using spinning disk atomization to prepare a nasal delivery dosage form that does not produce an irritation response. Release rates for the ETZ microcapsules were determined in vitro and an animal study was conducted to determine the irritation response of rat nasal mucosa when dosed with encapsulated vs. non-encapsulated ETZ.

Microplate and dot immunoassays for the serodiagnosis of tuberculosis.

A simple dot enzyme immunoassay based on the recognition of serum IgG antibody to a 30,000 dalton native antigen purified from culture filtrates of Mycobacterium tuberculosis was developed and compared with a standard plate enzyme-linked immunosorbent assay in the serodiagnosis of tuberculosis. The previously described favorable test characteristics of plate enzyme-linked immunoassay were confirmed; although the dot enzyme immunoassay was promising, it was less satisfactory. Dot enzyme immunoassay may have its most promising use as a screening test for situations of limited technical facilities. Both plate enzyme-linked immunoassay and dot enzyme immunoassay had markedly reduced sensitivities in persons with human immunodeficiency virus infection.