| 1. |
- Abramson, Alex, et al.
(författare)
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An ingestible self-orienting system for oral delivery of macromolecules
- 2019
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Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 363:6427, s. 611-
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Tidskriftsartikel (refereegranskat)abstract
- Biomacromolecules have transformed our capacity to effectively treat diseases; however, their rapid degradation and poor absorption in the gastrointestinal (GI) tract generally limit their administration to parenteral routes. An oral biologic delivery system must aid in both localization and permeation to achieve systemic drug uptake. Inspired by the leopard tortoise's ability to passively reorient, we developed an ingestible self-orienting millimeter-scale applicator (SOMA) that autonomously positions itself to engage with GI tissue. It then deploys milliposts fabricated from active pharmaceutical ingredients directly through the gastric mucosa while avoiding perforation. We conducted in vivo studies in rats and swine that support the applicator's safety and, using insulin as a model drug, demonstrated that the SOMA delivers active pharmaceutical ingredient plasma levels comparable to those achieved with subcutaneous millipost administration.
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| 2. |
- Barauskas, Justas, et al.
(författare)
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Phase behavior of the phytantriol/water system
- 2003
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 19:23, s. 9562-9565
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Tidskriftsartikel (refereegranskat)abstract
- Phytantriol, 3,7,11,15-tetramethyl-1,2,3-hexadecanetriol, is frequiently used as a cosmetic ingredient; however, very little is known about its physical and chemical properti s. Here, we present the phase behavior of phytantriol in water, as determined by X-ray diffraction. At room temperature, the phase sequence upon increasing the water concentration is reversed micellar, lamellar, cubic phase Q(230), and cubic phase Q(224). At 44 degreesC, the cubic liquid crystals are transformed into a reversed hexagonal phase. The temperature-composition phase diagram of phytantriol/water mixtures is, thus, qualitatively similar to that of aqueous glycerol monooleate. The chemical stability of phytantriol makes it an interesting alternative to glycerol monooleate in exploiting various scientific and technical applications of, in particular, the cubic liquid crystalline phases.
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| 3. |
- Landh, Tomas
(författare)
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Cubic Cell Membrane Architectures. Taking another look at membrane bound cell spaces
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A systematic study of cell membrane morphologies whose structure is governed by cubic symmetries has been performed. It is suggested that they are described by periodic cubic surfaces for which space filling surface foliations given by truncated Fourier series defined by the space groups is used as structural representations. Using this a method is developed which enables a direct ultrastructural comparison between calculated projected electron density maps of a given periodic cubic surface and transmission electron micrographs of biological specimens displaying cubic membrane morphologies. Convincing results are given for the existence of three families of periodic cubic structures based on the surfaces known as the gyroid, double-diamond, and primitive. In each family balanced, unbalanced, and morphologies with a set of multiple membrane foliations are perceived. The accuracy to which these morphologies are described as periodic cubic surfaces, and the ease with which parameters such as surface area and volume ratios can be calculated, suggest their utility as a stereologic tool. A manifold of membrane morphologies with hitherto unknown cubic symmetries is identified and classified to form in conjunction with endoplasmic reticulum, inner nuclear envelope, mitochondria, trans-Golgi apparatus, chloroplasts, plasma membrane and lysosomes. Their occurrence is concluded to be of general nature and representative examples are given in cells ranging from protozoa to man in a large variety of species and tissue types thereof. In all cases studied, formation of cubic membrane morphologies can be explained by an intersection-free membrane folding model. From analysis of a vast number of electron micrographs of particular cases of cubic membranes the existence of structurally invariant morphologies is conjectured. Examples include the prolamellar body and the t-tubular honeycomb networks of skeletal muscles, which are invariantly described in reference to a double diamond and a gyroid surface, respectively. Plausible structure-function relations for these are discussed. Several theories regarding the function of cubic membranes as subcellular space-partitioners are put forward. Noticeably, the cubic membrane morphologies described by a set of n multiple membrane foliations defines n + 1 subspaces inherent to the organelle. It is postulated to be of global validity in cell space partitioning and its possible significance is addressed.
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