The Experts below are selected from a list of 8979 Experts worldwide ranked by ideXlab platform
Calum J Drummond - One of the best experts on this subject based on the ideXlab platform.
-
Amphiphile micelle structures in the protic ionic liquid ethylammonium nitrate and water
Journal of Physical Chemistry B, 2015Co-Authors: Zhengfei Chen, Tamar L Greaves, Rachel A. Caruso, Calum J DrummondAbstract:Micelles formed by Amphiphiles in a protic ionic liquid (PIL), ethylammonium nitrate (EAN), were investigated using synchrotron small-angle X-ray scattering and contrasted with those that formed in water. The Amphiphiles studied were cationic hexadecyltrimethylammonium chloride (CTAC) and hexadecylpyridinium bromide (HDPB) and nonionic poly(oxyethylene) (10) oleyl ether (Brij 97) and Pluronic ethylene oxide–propylene oxide–ethylene oxide block copolymer (P123). The scattering patterns were analyzed using spherical, core–shell, and cylindrical scattering models. The apparent micelle shape and size of the surfactants and the block copolymer in the PIL have been reported. At low Amphiphile concentrations (<10 wt %) spherical micelles were preferentially formed for all the Amphiphiles in EAN. The micelles formed by the two cationic Amphiphiles in EAN and water were similar, though different scattering models were required predominantly due to the ionic nature of EAN. The two nonionic Amphiphiles formed micell...
-
nonionic diethanolamide Amphiphiles with saturated hydrocarbon chains neat crystalline and lyotropic liquid crystalline phase behavior
Joint International Conference on Information Sciences, 2012Co-Authors: Sharon M Sagnella, Charlotte E Conn, Irena Krodkiewska, Calum J DrummondAbstract:The solid state and lyotropic phase behavior of a series of nonionic diethanolamide Amphiphiles with increasing saturated hydrocarbon chain length (lauroyl, myristoyl, palmitoyl, and stearoyl) has been examined. All four saturated diethanolamide Amphiphiles form a crystalline solid with two or three different polymorphic crystalline forms at room temperature. Melting points and associated enthalpies for these four Amphiphiles increased with increasing chain length. Approximate partial binary phase diagrams have been constructed for each Amphiphile/water system by combining Cross-Polarized Optical Microscopy (POM) and Small-Angle X-ray Scattering (SAXS) results. In the presence of water, all four diethanolamides form an L(α) phase, between 10% and 50% water content, and an L(2) phase with decreasing hydration and increasing temperature. In addition to the L(α) and L(2) phases, the shorter chain diethanolamide Amphiphiles (lauroyl and myristoyl) also display a normal micellar phase (L(1)) at higher water contents, occurring to lower temperatures than the L(α) phase. By examining the effect of subtle molecular changes on both neat and lyotropic phase behavior, Amphiphiles can be designed with properties tailored to a desired application.
-
nonionic diethanolamide Amphiphiles with unsaturated c18 hydrocarbon chains thermotropic and lyotropic liquid crystalline phase behavior
Physical Chemistry Chemical Physics, 2011Co-Authors: Sharon M Sagnella, Charlotte E Conn, Irena Krodkiewska, Calum J DrummondAbstract:The neat and lyotropic liquid crystalline phase behavior of three nonionic diethanolamide Amphiphiles with C18 hydrocarbon chains containing one, two or three unsaturated bonds has been examined. This has allowed the effect of degree of unsaturation on the phase behavior of diethanolamide Amphiphiles to be investigated. Neat linoleoyl and linolenoyl diethanolamide undergo a transition from a glassy liquid crystal to a liquid crystal at ∼−85 °C, while neat oleoyl diethanolamide undergoes a transition at ∼−60 °C to a liquid crystalline material before re-crystallizing at −34 °C. Oleoyl diethanolamide then undergoes a third transition from a crystalline phase to a smectic liquid crystalline phase at ∼5 °C. In the absence of water, the transition temperature from a smectic liquid crystal to an isotropic liquid decreases with increasing unsaturation. The addition of water results in the formation of a lamellar phase (Lα) for all three Amphiphiles. The lamellar phase is stable under excess water conditions up to temperatures of at least 70 °C. Approximate partial binary Amphiphile-water phase diagrams generated for the three unsaturated C18 Amphiphiles indicate that the excess water point for each Amphiphile occurs at ∼60% (w/w) Amphiphile.
-
Ionic liquids as Amphiphile self-assembly media
Chemical Society Reviews, 2008Co-Authors: Tamar L Greaves, Calum J DrummondAbstract:In recent years, the number of non-aqueous solvents which mediate hydrocarbon–solvent interactions and promote the self-assembly of Amphiphiles has been markedly increased by the reporting of over 30 ionic liquids which possess this previously unusual solvent characteristic. This new situation allows a different exploration of the molecular ''solvophobic effect'' and tests the current understanding of Amphiphile self-assembly. Interestingly, both protic and aprotic ionic liquids support Amphiphile self-assembly, indicating that it is not required for the solvents to be able to form a hydrogen bonded network. Here, the use of ionic liquids as Amphiphile self-assembly media is reviewed, including micelle and liquid crystalline mesophase formation, their use as a solvent phase in microemulsions and emulsions, and the emerging field of nanostructured inorganic materials synthesis. Surfactants, lipids and block co-polymers are the focus Amphiphile classes in this critical review (174 references).
-
protic ionic liquids physicochemical properties and behavior as Amphiphile self assembly solvents
Journal of Physical Chemistry B, 2008Co-Authors: Tamar L Greaves, Irena Krodkiewska, Asoka Weerawardena, Calum J DrummondAbstract:The physicochemical properties of 22 protic ionic liquids (PILs) and 6 protic molten salts, and the self-assembly behavior of 3 Amphiphiles in the PILs, are reported. Structure−property relationships have been explored for the PILs, including the effect of increasing the substitution of ammonium cations and the presence of methoxy and hydroxyl moieties in the cation. Anion choices included the formate, pivalate, trifluoroacetate, nitrate, and hydrogen sulfate anions. This series of PILs had a diverse range of physicochemical properties, with ionic conductivities up to 51.10 mS/cm, viscosities down to 5.4 mPa·s, surface tensions between 38.3 and 82.1 mN/m, and densities between 0.990 and 1.558 g/cm3. PILs were designed with various levels of solvent cohesiveness, as quantified by the Gordon parameter. Fourteen PILs were found to promote the self-assembly of Amphiphiles. High-throughput polarized optical microscopy was used to identify lamellar, hexagonal, and bicontinuous cubic Amphiphile self-assembly pha...
Mikko Nikinmaa - One of the best experts on this subject based on the ideXlab platform.
-
influence of band 3 protein absence and skeletal structures on Amphiphile and ca2 induced shape alterations in erythrocytes a study with lamprey lampetra fluviatilis trout onchorhynchus mykiss and human erythrocytes
Biochimica et Biophysica Acta, 2000Co-Authors: Henry Hagerstrand, Malgorzata Danieluk, Malgorzata Bobrowskahagerstrand, Ales Iglic, Anna Wrobel, Boris Isomaa, Mikko NikinmaaAbstract:Amphiphiles which induce either spiculated (echinocytic) or invaginated (stomatocytic) shapes in human erythrocytes, and ionophore A23187 plus Ca 2a , were studied for their capacity to induce shape alterations, vesiculation and hemolysis in the morphologically and structurally different lamprey and trout erythrocytes. Both qualitative and quantitative differences were found. Amphiphiles induced no gross morphological changes in the non-axisymmetric stomatocyte-like lamprey erythrocyte or in the flat ellipsoidal trout erythrocyte, besides a rounding up at higher Amphiphile concentrations. No shapes with large broad spicula were seen. Nevertheless, some of the ‘echinocytogenic’ Amphiphiles induced plasma membrane protrusions in lamprey and trout erythrocytes, from where exovesicles were shed. In trout erythrocytes, occurrence of corrugations at the cell rim preceded protrusion formation. Other ‘echinocytogenic’ Amphiphiles induced invaginations in lamprey erythrocytes. The ‘stomatocytogenic’ Amphiphiles induced invaginations in both lamprey and trout erythrocytes. Surprisingly, in trout erythrocytes, some protrusions also occurred. Some of the Amphiphiles hemolyzed lamprey, trout and human erythrocytes at a significantly different concentration/membrane area. Ionophore A23187 plus Ca 2a induced membrane protrusions and sphering in human and trout erythrocytes ; however, the lamprey erythrocyte remained unperturbed. The shape alterations in lamprey erythrocytes, we suggest, are characterized by weak membrane skeleton^lipid bilayer interactions, due to band 3 protein and ankyrin deficiency. In trout erythrocyte, the marginal band of microtubules appears to strongly influence cell shape. Furthermore, the presence of intermediate filaments and nuclei, additionally affecting the cell membrane shear elasticity, apparently influences cell shape changes in lamprey and trout erythrocytes. The different types of shape alterations induced by certain Amphiphiles in the cell types indicates that their plasma membrane phospholipid composition differs. fl 2000 Elsevier Science B.V. All rights reserved.
-
influence of band 3 protein absence and skeletal structures on Amphiphile and ca 2 induced shape alterations in erythrocytes a study with lamprey lampetra fluviatilis trout onchorhynchus mykiss and human erythrocytes
Biochimica et Biophysica Acta, 2000Co-Authors: Henry Hagerstrand, Malgorzata Danieluk, Malgorzata Bobrowskahagerstrand, Ales Iglic, Anna Wrobel, Boris Isomaa, Mikko NikinmaaAbstract:Amphiphiles which induce either spiculated (echinocytic) or invaginated (stomatocytic) shapes in human erythrocytes, and ionophore A23187 plus Ca(2+), were studied for their capacity to induce shape alterations, vesiculation and hemolysis in the morphologically and structurally different lamprey and trout erythrocytes. Both qualitative and quantitative differences were found. Amphiphiles induced no gross morphological changes in the non-axisymmetric stomatocyte-like lamprey erythrocyte or in the flat ellipsoidal trout erythrocyte, besides a rounding up at higher Amphiphile concentrations. No shapes with large broad spicula were seen. Nevertheless, some of the 'echinocytogenic' Amphiphiles induced plasma membrane protrusions in lamprey and trout erythrocytes, from where exovesicles were shed. In trout erythrocytes, occurrence of corrugations at the cell rim preceded protrusion formation. Other 'echinocytogenic' Amphiphiles induced invaginations in lamprey erythrocytes. The 'stomatocytogenic' Amphiphiles induced invaginations in both lamprey and trout erythrocytes. Surprisingly, in trout erythrocytes, some protrusions also occurred. Some of the Amphiphiles hemolyzed lamprey, trout and human erythrocytes at a significantly different concentration/membrane area. Ionophore A23187 plus Ca(2+) induced membrane protrusions and sphering in human and trout erythrocytes; however, the lamprey erythrocyte remained unperturbed. The shape alterations in lamprey erythrocytes, we suggest, are characterized by weak membrane skeleton-lipid bilayer interactions, due to band 3 protein and ankyrin deficiency. In trout erythrocyte, the marginal band of microtubules appears to strongly influence cell shape. Furthermore, the presence of intermediate filaments and nuclei, additionally affecting the cell membrane shear elasticity, apparently influences cell shape changes in lamprey and trout erythrocytes. The different types of shape alterations induced by certain Amphiphiles in the cell types indicates that their plasma membrane phospholipid composition differs.
Tamar L Greaves - One of the best experts on this subject based on the ideXlab platform.
-
Amphiphile micelle structures in the protic ionic liquid ethylammonium nitrate and water
Journal of Physical Chemistry B, 2015Co-Authors: Zhengfei Chen, Tamar L Greaves, Rachel A. Caruso, Calum J DrummondAbstract:Micelles formed by Amphiphiles in a protic ionic liquid (PIL), ethylammonium nitrate (EAN), were investigated using synchrotron small-angle X-ray scattering and contrasted with those that formed in water. The Amphiphiles studied were cationic hexadecyltrimethylammonium chloride (CTAC) and hexadecylpyridinium bromide (HDPB) and nonionic poly(oxyethylene) (10) oleyl ether (Brij 97) and Pluronic ethylene oxide–propylene oxide–ethylene oxide block copolymer (P123). The scattering patterns were analyzed using spherical, core–shell, and cylindrical scattering models. The apparent micelle shape and size of the surfactants and the block copolymer in the PIL have been reported. At low Amphiphile concentrations (<10 wt %) spherical micelles were preferentially formed for all the Amphiphiles in EAN. The micelles formed by the two cationic Amphiphiles in EAN and water were similar, though different scattering models were required predominantly due to the ionic nature of EAN. The two nonionic Amphiphiles formed micell...
-
Ionic liquids as Amphiphile self-assembly media
Chemical Society Reviews, 2008Co-Authors: Tamar L Greaves, Calum J DrummondAbstract:In recent years, the number of non-aqueous solvents which mediate hydrocarbon–solvent interactions and promote the self-assembly of Amphiphiles has been markedly increased by the reporting of over 30 ionic liquids which possess this previously unusual solvent characteristic. This new situation allows a different exploration of the molecular ''solvophobic effect'' and tests the current understanding of Amphiphile self-assembly. Interestingly, both protic and aprotic ionic liquids support Amphiphile self-assembly, indicating that it is not required for the solvents to be able to form a hydrogen bonded network. Here, the use of ionic liquids as Amphiphile self-assembly media is reviewed, including micelle and liquid crystalline mesophase formation, their use as a solvent phase in microemulsions and emulsions, and the emerging field of nanostructured inorganic materials synthesis. Surfactants, lipids and block co-polymers are the focus Amphiphile classes in this critical review (174 references).
-
protic ionic liquids physicochemical properties and behavior as Amphiphile self assembly solvents
Journal of Physical Chemistry B, 2008Co-Authors: Tamar L Greaves, Irena Krodkiewska, Asoka Weerawardena, Calum J DrummondAbstract:The physicochemical properties of 22 protic ionic liquids (PILs) and 6 protic molten salts, and the self-assembly behavior of 3 Amphiphiles in the PILs, are reported. Structure−property relationships have been explored for the PILs, including the effect of increasing the substitution of ammonium cations and the presence of methoxy and hydroxyl moieties in the cation. Anion choices included the formate, pivalate, trifluoroacetate, nitrate, and hydrogen sulfate anions. This series of PILs had a diverse range of physicochemical properties, with ionic conductivities up to 51.10 mS/cm, viscosities down to 5.4 mPa·s, surface tensions between 38.3 and 82.1 mN/m, and densities between 0.990 and 1.558 g/cm3. PILs were designed with various levels of solvent cohesiveness, as quantified by the Gordon parameter. Fourteen PILs were found to promote the self-assembly of Amphiphiles. High-throughput polarized optical microscopy was used to identify lamellar, hexagonal, and bicontinuous cubic Amphiphile self-assembly pha...
-
many protic ionic liquids mediate hydrocarbon solvent interactions and promote Amphiphile self assembly
Langmuir, 2007Co-Authors: Tamar L Greaves, Asoka Weerawardena, Celesta Fong, Calum J DrummondAbstract:A large number of protic ionic liquids (PILs) have been found to mediate solvent-hydrocarbon interactions and promote Amphiphile self-assembly. Hexagonal, cubic, and lamellar lyotropic liquid crystalline phases were observed in PIL-hexadecyltrimethylammonium bromide systems. The driving force for the formation of the self-assembled aggregate structures has been attributed to an entropic contribution to the free energy of association, analogous to the hydrophobic effect in water. The specific aggregate structures formed depend upon the cationic and anionic components of the PIL and their interactions with the Amphiphiles.
Samuel I Stupp - One of the best experts on this subject based on the ideXlab platform.
-
chromophore Amphiphile polyelectrolyte hybrid hydrogels for photocatalytic hydrogen production
Journal of Materials Chemistry, 2020Co-Authors: Hiroaki Sai, Aykut Erbas, Adam J Dannenhoffer, Dongxu Huang, Adam S Weingarten, Erica Siismets, Kyujin Jang, Liam C Palmer, Monica Olvera De La Cruz, Samuel I StuppAbstract:Hybrid systems based on covalent polymers and supramolecular assemblies offer unique opportunities for functional materials based on the pathway-dependent dynamic structures of supramolecular assemblies and the mechanical stability of covalent polymers. We report here on the synthesis of functional hybrid hydrogels containing self-assembling chromophore Amphiphiles and polyelectrolytes. Chromophore Amphiphiles were introduced into non-aqueous solvent swollen polymer matrices and self-assembly of the chromophore Amphiphiles into crystalline nanostructures was triggered in the confined environment of the covalent network upon solvent exchange for water. Opposite charges in the covalent polyelectrolyte and the chromophore Amphiphiles and sterics entrap the supramolecular assemblies within the mechanically stable network. However, molecular components necessary for catalysis, byproducts from photocatalysis, and the hydrogen produced are able to diffuse in or out of the covalent network to create a reusable robust host for photocatalysis. By varying the monomer and crosslinker composition in the feed, we can tune the porosity of the network as well as the chemical environment in which supramolecular crystallization of the chromophore Amphiphiles takes place. This allows optimization of the hydrogel mechanical properties, retention of the chromophore Amphiphile assemblies, and the photocatalytic reaction efficiency. Coarse-grained molecular dynamics simulations revealed that the chromophore Amphiphile assembly is guided by the polyelectrolyte network via ionic interactions. We also demonstrate successful photocatalytic hydrogen production from catalyst-laden hybrid hydrogels with the turnover frequency approaching that of the supramolecular hydrogel system, and also show that the hybrid hydrogels can be reused over multiple cycles as photosensitizers.
-
alginate peptide Amphiphile core shell microparticles as a targeted drug delivery system
RSC Advances, 2015Co-Authors: Job Boekhoven, Helen R Zha, Faifan Tantakitti, Ellen Zhuang, Roya Zandi, Christina J Newcomb, Samuel I StuppAbstract:We describe in this work the synthesis of microparticles with a doxorubicin drug conjugated alginate core and a shell of peptide Amphiphile nanofibres functionalized for targeting the folate receptor. The spherical geometry of the particle core allows high drug loading per surface area, whereas the nanoscale fibrous shell formed by self-assembly of peptide Amphiphiles offers a high surface to volume ratio that is ideal for targeting. The synthesised microparticles have a 60-fold higher cytotoxicity against MDA-MB-231 breast cancer cells compared to non-targeting particles.
-
supramolecular nanofibers of peptide Amphiphiles for medicine
Israel Journal of Chemistry, 2013Co-Authors: Matthew J. Webber, Eric J Berns, Samuel I StuppAbstract:: Peptide nanostructures are an exciting class of supramolecular systems that can be designed for novel therapies with great potential in advanced medicine. This paper reviews progress on nanostructures based on peptide Amphiphiles capable of forming one-dimensional assemblies that emulate in structure the nanofibers present in extracellular matrices. These systems are highly tunable using supramolecular chemistry, and can be designed to signal cells directly with bioactive peptides. Peptide Amphiphile nanofibers can also be used to multiplex functions through co-assembly and designed to deliver proteins, nucleic acids, drugs, or cells. We illustrate here the functionality of these systems describing their use in regenerative medicine of bone, cartilage, the nervous system, the cardiovascular system, and other tissues. In addition, we highlight recent work on the use of peptide Amphiphile assemblies to create hierarchical biomimetic structures with order beyond the nanoscale, and also discuss the future prospects of these supramolecular systems.
-
Self-assembly of peptide Amphiphiles: from molecules to nanostructures to biomaterials.
Biopolymers, 2010Co-Authors: Honggang Cui, Matthew J. Webber, Samuel I StuppAbstract:Peptide Amphiphiles are a class of molecules that combine the structural features of amphiphilic surfactants with the functions of bioactive peptides and are known to assemble into a variety of nanostructures. A specific type of peptide Amphiphiles are known to self-assemble into one-dimensional nanostructures under physiological conditions, predominantly nanofibers with a cylindrical geometry. The resultant nanostructures could be highly bioactive and are of great interest in many biomedical applications, including tissue engineering, regenerative medicine, and drug delivery. In this context, we highlight our strategies for using molecular self-assembly as a toolbox to produce peptide Amphiphile nanostructures and materials and efforts to translate this technology into applications as therapeutics. We also review our recent progress in using these materials for treating spinal cord injury, inducing angiogenesis, and for hard tissue regeneration and replacement.
-
Peptide Amphiphile nanostructure-heparin interactions and their relationship to bioactivity.
Biomaterials, 2008Co-Authors: Kanya Rajangam, Michael S. Arnold, Mark A. Rocco, Samuel I StuppAbstract:Abstract Heparin–protein interactions are important in many physiological processes including angiogenesis, the growth of new blood vessels from existing ones. We have previously developed a highly angiogenic self-assembling gel, wherein the self-assembly process is triggered by the interactions between heparin and peptide Amphiphiles (PAs) with a consensus heparin binding sequence. In this report, this consensus sequence was scrambled and incorporated into a new peptide Amphiphile in order to study its importance in heparin interaction and bioactivity. Heparin was able to trigger gel formation of the scrambled peptide Amphiphile (SPA). Furthermore, the affinity of the scrambled molecule for heparin was unchanged as shown by isothermal titration calorimetry and high Forster resonance emission transfer efficiency. However, both the mobile fraction and the dissociation rate constant of heparin, using fluorescence recovery after photobleaching, were markedly higher in its interaction with the scrambled molecule implying a weaker association. Importantly, the scrambled peptide Amphiphile–heparin gel had significantly less angiogenic bioactivity as shown by decreased tubule formation of sandwiched endothelial cells. Hence, we believe that the presence of the consensus sequence stabilizes the interaction with heparin and is important for the bioactivity of these new materials.
Henry Hagerstrand - One of the best experts on this subject based on the ideXlab platform.
-
influence of band 3 protein absence and skeletal structures on Amphiphile and ca2 induced shape alterations in erythrocytes a study with lamprey lampetra fluviatilis trout onchorhynchus mykiss and human erythrocytes
Biochimica et Biophysica Acta, 2000Co-Authors: Henry Hagerstrand, Malgorzata Danieluk, Malgorzata Bobrowskahagerstrand, Ales Iglic, Anna Wrobel, Boris Isomaa, Mikko NikinmaaAbstract:Amphiphiles which induce either spiculated (echinocytic) or invaginated (stomatocytic) shapes in human erythrocytes, and ionophore A23187 plus Ca 2a , were studied for their capacity to induce shape alterations, vesiculation and hemolysis in the morphologically and structurally different lamprey and trout erythrocytes. Both qualitative and quantitative differences were found. Amphiphiles induced no gross morphological changes in the non-axisymmetric stomatocyte-like lamprey erythrocyte or in the flat ellipsoidal trout erythrocyte, besides a rounding up at higher Amphiphile concentrations. No shapes with large broad spicula were seen. Nevertheless, some of the ‘echinocytogenic’ Amphiphiles induced plasma membrane protrusions in lamprey and trout erythrocytes, from where exovesicles were shed. In trout erythrocytes, occurrence of corrugations at the cell rim preceded protrusion formation. Other ‘echinocytogenic’ Amphiphiles induced invaginations in lamprey erythrocytes. The ‘stomatocytogenic’ Amphiphiles induced invaginations in both lamprey and trout erythrocytes. Surprisingly, in trout erythrocytes, some protrusions also occurred. Some of the Amphiphiles hemolyzed lamprey, trout and human erythrocytes at a significantly different concentration/membrane area. Ionophore A23187 plus Ca 2a induced membrane protrusions and sphering in human and trout erythrocytes ; however, the lamprey erythrocyte remained unperturbed. The shape alterations in lamprey erythrocytes, we suggest, are characterized by weak membrane skeleton^lipid bilayer interactions, due to band 3 protein and ankyrin deficiency. In trout erythrocyte, the marginal band of microtubules appears to strongly influence cell shape. Furthermore, the presence of intermediate filaments and nuclei, additionally affecting the cell membrane shear elasticity, apparently influences cell shape changes in lamprey and trout erythrocytes. The different types of shape alterations induced by certain Amphiphiles in the cell types indicates that their plasma membrane phospholipid composition differs. fl 2000 Elsevier Science B.V. All rights reserved.
-
influence of band 3 protein absence and skeletal structures on Amphiphile and ca 2 induced shape alterations in erythrocytes a study with lamprey lampetra fluviatilis trout onchorhynchus mykiss and human erythrocytes
Biochimica et Biophysica Acta, 2000Co-Authors: Henry Hagerstrand, Malgorzata Danieluk, Malgorzata Bobrowskahagerstrand, Ales Iglic, Anna Wrobel, Boris Isomaa, Mikko NikinmaaAbstract:Amphiphiles which induce either spiculated (echinocytic) or invaginated (stomatocytic) shapes in human erythrocytes, and ionophore A23187 plus Ca(2+), were studied for their capacity to induce shape alterations, vesiculation and hemolysis in the morphologically and structurally different lamprey and trout erythrocytes. Both qualitative and quantitative differences were found. Amphiphiles induced no gross morphological changes in the non-axisymmetric stomatocyte-like lamprey erythrocyte or in the flat ellipsoidal trout erythrocyte, besides a rounding up at higher Amphiphile concentrations. No shapes with large broad spicula were seen. Nevertheless, some of the 'echinocytogenic' Amphiphiles induced plasma membrane protrusions in lamprey and trout erythrocytes, from where exovesicles were shed. In trout erythrocytes, occurrence of corrugations at the cell rim preceded protrusion formation. Other 'echinocytogenic' Amphiphiles induced invaginations in lamprey erythrocytes. The 'stomatocytogenic' Amphiphiles induced invaginations in both lamprey and trout erythrocytes. Surprisingly, in trout erythrocytes, some protrusions also occurred. Some of the Amphiphiles hemolyzed lamprey, trout and human erythrocytes at a significantly different concentration/membrane area. Ionophore A23187 plus Ca(2+) induced membrane protrusions and sphering in human and trout erythrocytes; however, the lamprey erythrocyte remained unperturbed. The shape alterations in lamprey erythrocytes, we suggest, are characterized by weak membrane skeleton-lipid bilayer interactions, due to band 3 protein and ankyrin deficiency. In trout erythrocyte, the marginal band of microtubules appears to strongly influence cell shape. Furthermore, the presence of intermediate filaments and nuclei, additionally affecting the cell membrane shear elasticity, apparently influences cell shape changes in lamprey and trout erythrocytes. The different types of shape alterations induced by certain Amphiphiles in the cell types indicates that their plasma membrane phospholipid composition differs.