Breaking News
June 23, 2018 - FDA Alert: Kratom (mitragyna speciosa) powder products by Gaia Ethnobotanical: Recall
June 23, 2018 - CDC chief asks for, and gets, cut to his record $375K pay
June 22, 2018 - Novel cellular pathway may clarify how arterial inflammation develops into atherosclerosis
June 22, 2018 - Rutgers Cancer Institute educates childhood cancer survivors about late effects of treatment
June 22, 2018 - Study tests accuracy of device designed to detect heart dysfunction in childhood cancer survivors
June 22, 2018 - Study links annual haze with increased hospitalizations for respiratory problems
June 22, 2018 - Robotic surgery appears to be as effective as open surgery in treating bladder cancer
June 22, 2018 - Many Drugs Made Available Via FDA Expanded Access Programs
June 22, 2018 - Normal eye dominance is not necessary for restoring visual acuity in amblyopia
June 22, 2018 - Parent-Child Interaction Therapy can reduce depression rates in children
June 22, 2018 - Study provides insights into how components of different cells in the brain are altered
June 22, 2018 - Research does not confirm antidiabetic action of natural fatty acid derivatives
June 22, 2018 - Oxidative stress can be used against tumors to treat cancer
June 22, 2018 - Simple, cost-effective test may help improve early diagnosis of mild cognitive impairment
June 22, 2018 - New guide published to help battle fatal disease caused by kissing bugs
June 22, 2018 - Stigma Adds to Burden of Type 1 Diabetes
June 22, 2018 - In retinoblastoma survivors, oculo-visual issues tied to QoL
June 22, 2018 - Most adults with allergies do not use prescribed epinephrine even in emergency situations
June 22, 2018 - Study provides clues to how cancer cells develop resistance to chemotherapies
June 22, 2018 - New consensus paper serves as basis for uniform medical management of DSD
June 22, 2018 - Researchers work to identify areas of the brain that help us wake up
June 22, 2018 - Alcohol hangovers more significant and costly than people realize, shows research
June 22, 2018 - Targeting cells involved in blood vessel formation could hinder brain tumor growth
June 22, 2018 - Young cancer survivors need more support as they feel dissatisfied with their sexuality
June 22, 2018 - Unusual cell-to-cell communication in glioblastoma promotes aggressiveness and therapy resistance
June 22, 2018 - Turning A Phage – Drug Discovery Today
June 22, 2018 - World-first study links birth interventions and long-term childhood illness
June 22, 2018 - Improving the quality of biomedical research samples
June 22, 2018 - Researchers identify cerebral palsy using AI and DNA sequencing
June 22, 2018 - Administering nitric oxide gas after heart surgery may decrease risk of kidney problems
June 22, 2018 - Measuring levels of ethyl sulphate in hair can help assess alcohol consumption
June 22, 2018 - Researchers develop robot bloodhound that can rapidly detect odors on the ground
June 22, 2018 - AAA doses first patients in two clinical studies with PSMA-R2 for prostate cancer
June 22, 2018 - Researchers discover drug compound that inhibits movement of cancer cells
June 22, 2018 - Normalization of ‘plus-size’ body shapes may prevent recognition of health risks of obesity
June 22, 2018 - UC San Diego launches new bacteriophage therapy center
June 22, 2018 - New review outlines current state of sex-sensitive issues linked to heart failure drugs
June 22, 2018 - Pelvic pain a major issue for women nearing mid-life, research reveals
June 22, 2018 - Researchers develop reliable DNA barcodes for biomedical research
June 22, 2018 - New risk-prediction model may help identify diabetic patients at high risk of pancreatic cancer
June 22, 2018 - Study reveals how mTORC1-driven changes in crowding could influence major diseases
June 22, 2018 - Researchers uncover new therapeutic opportunity in the treatment of malignant melanoma
June 22, 2018 - UC Riverside researcher receives grants to advance cancer, ALS research
June 22, 2018 - Radiation therapy alone may be enough to treat older, sicker patients with anal cancers
June 22, 2018 - Technical report describes how to make accurate particle size measurements on carbon black samples
June 22, 2018 - Nocdurna (desmopressin acetate) Approved by FDA as First Sublingual Tablet to Treat Nocturia due to Nocturnal Polyuria
June 22, 2018 - Neuroscientists locate neurons in the brain that respond when a visual target is found
June 22, 2018 - First human Keystone virus infection reported
June 22, 2018 - New study reveals how ‘good’ bacteria help in regulating our metabolism
June 22, 2018 - Osteopathic manual therapy affecting the diaphragm improves chronic low back pain
June 22, 2018 - Researchers create revolutionary model to study pulmonary diseases
June 22, 2018 - Diagnosing Heart Disease Using AI
June 22, 2018 - Increasing biodefense risks posed by synthetic biology
June 22, 2018 - Many Women Report Vasomotor Symptoms in Their 60s
June 22, 2018 - Rare mutation of gene carried by Quebec family gives insight into how the brain is wired
June 22, 2018 - Chemists find new way to make enzymes do a non-natural reaction
June 22, 2018 - Summer is good time to check for signs of skin cancer
June 22, 2018 - Innovative method can help identify patients with spastic cerebral palsy
June 22, 2018 - Exercise alters characteristics of blood to reduce inflammation in obese people
June 22, 2018 - Researchers examine complications across different types of breast reconstructive surgeries
June 22, 2018 - Rhesus macaque model could be useful to test therapies for congenital Zika virus syndrome
June 22, 2018 - AHA: New Insights Into Sickle Cell and Stroke Risk
June 22, 2018 - Doctors prescribe opioids at high rates to those at increased overdose risk
June 22, 2018 - Reduction in US cigarette smoking rates
June 22, 2018 - Preconception binge drinking may have negative effect on future offspring
June 22, 2018 - FDA expands approval of novel diabetes management device to include younger pediatric patients
June 22, 2018 - Researchers confirm weight loss benefits of the 16:8 diet
June 22, 2018 - FDA approves Eversense CGM system for use in adults with diabetes
June 22, 2018 - State opioid monitoring programs are not created equal
June 22, 2018 - Autistic teens who are bullied have higher rates of depression
June 22, 2018 - Penn Medicine team launches universal stroke awareness program
June 22, 2018 - Scientists discover the molecular trigger of necroptosis
June 22, 2018 - Researchers report unusually high levels of herpesvirus in the brains of people with Alzheimer’s disease
June 22, 2018 - Theoretical models predict how juveniles evolve to be more susceptible than adults to infection
June 22, 2018 - USC study reveals how the cell launches emergency response to repair damaged DNA
June 22, 2018 - $1.9 million grant aims to enhance behavioral health services in community-based settings
June 22, 2018 - New 3D imaging technique could improve arthritis treatment
June 22, 2018 - Cytokinetics Announces Data From Phase 2 Clinical Study of Reldesemtiv in Patients With Spinal Muscular Atrophy
June 22, 2018 - Polarized cells give the heart its fully developed form
June 21, 2018 - Stem cells appear to help fight obesity in animal models
Producing Super-Swelled Lyotropic Crystals for Drug Development

Producing Super-Swelled Lyotropic Crystals for Drug Development

image_pdfDownload PDFimage_print

What are lyotropic liquid crystals? How are they used in drug development?

Liquid crystals are state of matter that have properties of liquids and crystals. There are several types of liquid crystal materials. There are some that change their properties as a response to temperature, called thermotropic liquid crystals, and others that change in response to a solvent. These are called lyotropic liquid crystals and in most cases the solvent is water.

Liposomes. Credit: RomanenkoAlexey/Shutterstock.com

Lyotropic liquid crystals are used in drug development because they are liquids, however, they do have some crystalline properties. There useful in drug development as they can be organized into structures that are ideal to encapsulate drugs and other bioactive molecules.

Lyotropic liquid crystals are used because they remain stable in water, which makes up a large percentage of the human body. Aqueous structures are essential for drug delivery in vivo, which is why lyotropic liquid crystals are so useful.

What methodologies have been used to produce lyotropic liquid crystals for drug development in the past?

Liposomes are the most used lyotropic liquid crystal for drug development. They are characterized by a membrane sphere with water and the target drug inside. The way drugs are developed using this method is complex.

You start with a lyotropic liquid crystal, which is a bilayer, or lamellar phase, that looks very much like sheets of a cell membrane. Then, you apply a technique to make little particles come out of the crystal. Following this, you add water and agitate the membrane. This causes the crystal to close-up into spheres with water on the inside; where the drug will go.

However, there are alternative methods. One example is bicontinuous cubic phases, which are three-dimensional objects that have lots of pores. The discovery of bicontinuous cubic phases got scientists thinking, “Well instead of just making liposomes, we can make other types of particles with other types of structures, and that might be beneficial”.

Due to their highly porous nature, these structures can, in theory, hold a larger amount of cargo than liposomes, making them superior structures for drug delivery. But to this day, liposomes are still the leading lyotropic liquid crystal used in drug delivery. This is because bicontinuous cubic phases are difficult to process and their pores are too small.

What are the limitations of the current methods used to produce lyotropic liquid crystals? Why is it important that new methods are developed?

Liposomes are great and very useful, but there are certain drugs that can crystallize inside them. If you have a method that uses a perforated membrane like bicontinuous cubic phases, larger, more complex drugs can be delivered, as the structure has an increased surface to volume ratio.

Another limitation of liposomes is that the drugs need to be soluble. This is a problem for hydrophobic drugs that won’t go into the water domain. They will want to go into the hydrophobic core of the membrane.

In liposomes you only have one membrane that encloses the drug. If you have other phases, like bicontinuous cubic phases, where the particle is made up of perforated membranes that allow the water to enter pores, you have a particle that is a continuum of water and fat everywhere.

If a liposome is, say, 200 nanometers, then those 200 nanometers are mostly made up of water. With bicontinuous cubic phases, you have tons of membranes that are continuous in both polar and hydrophobic domains. This means you can encapsulate drugs that are both water soluble and not water insoluble.

Then there are other advantages. For example, bicontinuous cubic phases are known to have a preferential interaction with cell membranes, allowing easier delivery of drugs into cells of the body.

Please outline your recent research involving lyotropic liquid crystals.

Traditionally, lyotropic liquid crystals had pores that are really small, only about three nanometers. So, there was a limit of what kind of drugs or proteins you could encapsulate within them. Our recent findings describe a new processing technique that allowed us to expand those pores to five times larger than previous methods, so they are now around 15 nanometers in size.

Dr. Cecilia Leal holding a 3D printed model of a super-swelled bicontinuous cubic phase monocrystal

Why are super-swelled lyotropic monocrystals such an advancement?

The first advancement was that we could make these materials with larger pores than ever before. The second was that the materials that we had generated were extremely stable for months. This is because, instead of existing as a collection of membranes, the liquid crystals had formed a monocrystal with extremely large pores.

Typically, if you do anything with membranes, or soft materials in general, you have these small unit cells or these small crystals or micro crystallites that appear. They are the size of a micron and are randomly oriented in all directions in solution.

We’ve found that if you let these highly porous membranes rest for a few months, they develop into a single crystal that is more than one cubic millimeter. It’s no longer micrometer size, its macro size; you can see it with the human eye.

What’s surprising to us is that, the crystal is still able to hold a lot of water. It’s 90% water, and is still soft but is also a crystalline shape like a diamond. That was very surprising to us. Not only that it is super swollen, but that it was also incredibly well-organized.

Whilst this might not be useful for drug development, it may be useful for protein crystallization. This has actually been used in a recent paper for Nature Communications. The researchers used our method to encapsulate the Gloeobacter ligand-gated ion channel protein (GLIC) when they crystallized it.

How did you find out that fast chloroform removal was crucial for producing lyotropic monocrystals?

If you want to develop a material using a mixture of liposomes or any form of lipid molecules, they first need to be solubilized in an organic solvent. The most commonly used solvent is chloroform, which is removed slowly and completely, creating the lyotropic liquid crystal. The addition of water turns the crystal into a liposome or bicontinuous cubic phase.

My student was working with some of these lipid mixtures, and was in a rush to move to the next step. This meant he removed the chloroform really fast. He then added the water and saw these super swollen phases develop.

He told me he’d messed up but when we looked, the solvent had been completely removed, so it was only the speed that differed, as it is usually done very slowly. He then started working on this method, comparing the size of the phases that develop from a slow, medium and fast speed of chloroform extraction.

He found that when you add water then the size of the pores that develop are a function of the speed at which the solvent is removed.  If you do this slowly you get the regular size, and if you do fast you get these super swollen phases.

We assumed it was a kinetic effect that wouldn’t be stable. But, it was stable, not thermodynamically, but it was stable. We let it sit for six months and found that not only was it still stable, it was actually more organized.  

In fact, liposomes are not thermodynamically stable either. They are formed via kinetic traps that are stable when you need to apply them but not thermodynamically, therefore this is not a limitation of our discovery. It’s been a year since we first discovered this method and our sample is still in the lab today.

What applications are there for super-swelled lyotropic monocrystals? What impact will the new methodology have on research?

I think the major applications of our research will be in protein crystallization. This is important because this is at the forefront of research, with the development of useful technologies such as Cryo-EM and imaging techniques to determine protein structure.

The leading technology to determine protein structure is crystallography. The limitations of current techniques are that most proteins are difficult to crystallize. Before our discovery, the number of proteins that you could crystallize was very limited. This was because the pores were so small that are only a handful of proteins could be crystallized.

In the future, do you think super-swelled lyotropic monocrystals will be routinely used in research and drug development?

Yes, I hope so. The good thing about the method is that it is a relatively easy processing technique, meaning it is accessible to many scientists. It is also a reliable technique as the materials themselves are highly flexible. For example, let’s say you want to use a cocktail of three different lipids that target a specific cell type, with this method, you could use any lipid as long as you removed the solvent fast.

I think that it will have a big impact. However, the widespread use of new techniques take time. People are very used to working with liposomes and they are more familiar than other more complicated structures.

Where can readers find more information?

  • Dr. Cecilia Leal’s profile for The University of Illinois
  • The Leal Research group
  • Zabara, A., Chong, J., Martiel, I., Stark, L., Cromer, B., Speziale, C., Drummond, C. and Mezzenga, R. (2018). Design of ultra-swollen lipidic mesophases for the crystallization of membrane proteins with large extracellular domains. Nature Communications.

About Dr. Cecília Leal

Cecília Leal is an Assistant Professor in the Department of Materials Science and Engineering and the Frederick Seitz Materials Research Laboratory at the University of Illinois, Urbana-Champaign. She graduated in Industrial Chemistry from Coimbra University in Portugal before moving to Sweden to do a PhD in physical chemistry at Lund University, supervised by Professor Wennerström.

After working for a year in the Norwegian Radium Hospital, she joined Professor Safinya’s Lab at the University of California, Santa Barbara, as a postdoctoral fellow.

Her research interests focus on the characterization and functionalization of lipid materials for cellular delivery. She is the recipient of the National Institutes of Health New Innovator award (2016), the National Science Foundation CAREER award (2016), and the University of Illinois Dean’s Award of Excellence in Research (2018).

Tagged with:

About author

Related Articles