Technical articles
R&D Judgment for Phospholipid Reagents: Headgroup Type, Fatty Acyl Chain Structure, and Phase Transition Temperature
R&D Judgment for Phospholipid Reagents: Headgroup Type, Fatty Acyl Chain Structure, and Phase Transition Temperature
Introduction
Phospholipid reagents are commonly used in liposomes, model membranes, drug delivery systems, and formulation screening. One of the easiest mistakes in R&D is to treat “phospholipids” as a single class with broadly similar properties. In practice, experimental behavior is usually governed by three variables: headgroup charge, fatty acyl chain structure, and the phase transition temperature jointly shaped by the first two. Recent reviews likewise place the R&D value of phospholipids at the level of how structural features determine self-assembly, membrane state, and application performance.
Once these three variables are clearly distinguished, many common questions become much more straightforward. Why do DOPC and DSPC, both phosphatidylcholines, behave so differently at room temperature? Why do some systems require changing the headgroup first, while others require changing the fatty acyl chain first? Why do hydration, extrusion, and particle-size stability often become problematic together when the experimental temperature does not cross the phase transition temperature? This article addresses these questions in the following order: what to judge first, what to compare next, and finally how to translate those judgments into R&D tasks.
1. In the Initial Screening of Phospholipid Reagents and Membrane Systems, Start with Three Variables
In phospholipid reagent selection, model membrane construction, liposome formulation exploration, and early-stage screening of delivery systems, the usual starting point is to first verify three pieces of information: the headgroup, the fatty acyl chain, and the phase transition temperature. The headgroup and fatty acyl chain together determine the physical properties of the membrane, while the phase transition temperature determines the state in which those properties manifest at the current experimental temperature.
What to examine first | What needs to be confirmed first | What it mainly affects | The experimental questions it most often corresponds to |
Headgroup | Whether it is zwitterionic or anionic | Surface electrostatics, interfacial hydration, and interactions with ions or charged molecules | Whether the surface potential of the system will change, whether a negatively charged headgroup needs to be introduced, and whether charged molecules will bind more readily to the membrane surface |
Fatty acyl chain | Whether it is long-chain or short-chain, saturated or unsaturated, symmetric or mixed-chain | Membrane packing density, fluidity, degree of order, and thermal response | Whether the membrane is relatively rigid or relatively soft, whether a more fluid bilayer can form readily at room temperature, and whether changes in chain structure will clearly separate membrane states |
Phase transition temperature | Whether the experimental temperature is below, near, or above the phase transition temperature | Whether the bilayer is in a more ordered or more fluid state | Whether hydration proceeds smoothly, whether extrusion and homogenization are easy to carry out, and whether particle size and membrane state fluctuate readily with temperature |
In experiments involving film formation, hydration, extrusion, temperature-controlled dispersion, or comparison of membrane fluidity, the phase transition temperature should be checked first. When the experimental temperature is below the phase transition temperature, the bilayer is usually more ordered, more rigid, and slower to rearrange; when it is above the phase transition temperature, the bilayer is closer to the liquid-crystalline state, and hydration and membrane rearrangement are usually easier to achieve. When temperature and material state do not match, many downstream phenomena tend to be amplified simultaneously.
2. The Experimental Significance of Headgroup Type: Surface Electrostatics, Interfacial Hydration, and Interactions
2.1 Headgroup Type Determines Where Interfacial Properties Begin to Diverge
Among common phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are usually discussed as zwitterionic phospholipids with a net charge of 0, whereas phosphatidylglycerol (PG), phosphatidylserine (PS), and phosphatidic acid (PA) are more often treated as anionic phospholipids. This distinction is first reflected in membrane surface electrostatics, counterion binding, and modes of interaction with charged molecules. Among them, PA has a smaller headgroup, is more sensitive to pH and the counterion environment, and is also more likely to participate in curvature-related membrane rearrangements; in practical use, it should not be treated as fully equivalent to a general anionic headgroup.
The role of the headgroup is not limited to charge. Under the same fatty acyl chain conditions, changing the headgroup also alters interfacial hydration, molecular packing, and membrane elasticity. Relevant studies show that the headgroup and fatty acyl chain jointly regulate the area per lipid and elastic properties of membranes; PC and PE also differ in hydration behavior, and PE is more prone to show a stronger tendency toward non-bilayer structures.
2.2 Situations Where the Headgroup Should Be Adjusted First
When the experimental question centers on surface electrostatics, adsorption of charged molecules, response to the ionic environment, or interfacial recognition behavior, adjusting the headgroup first is usually more direct. When the goal is to first establish a near-electroneutral and relatively robust bilayer baseline, it is usually better to start with PC; PE is more suitable as a headgroup control or helper lipid for modulating membrane packing, curvature, and fusion behavior; when a more clearly negatively charged interface is needed, PG, PS, and PA deserve priority in comparison. In protein binding, interfacial adsorption, and ionic response, anionic phospholipids often behave differently from zwitterionic phospholipids.
Changing the headgroup cannot substitute for the roles of the fatty acyl chain and phase transition temperature. Replacing PC with PG does not automatically turn a high-phase-transition-temperature system into a low-phase-transition-temperature one; replacing PE with PC likewise cannot substitute for the decisive effects of chain length and unsaturation on membrane fluidity and thermal behavior. A more reliable approach is to separate these two levels of questions: use the headgroup first to judge interfacial properties, then use the fatty acyl chain and phase transition temperature to judge membrane state.
2.3 Common Headgroup Types and the Experimental Questions to Observe First
Headgroup type | Common representatives | Charge characteristic | Experimental questions affected |
Zwitterionic | PC, PE | Net charge of 0 | Whether the surface is close to electrically neutral, and how interfacial hydration and molecular packing will change |
Anionic | PG, PS, PA | Net negative charge | How surface potential, counterion binding, and interactions with positively charged molecules will change |
3. Fatty Acyl Chain Structure and Main Phase Transition Temperature
3.1 How Chain Length, Unsaturation, and Mixed-Chain Structure Change Membrane State
When the headgroup is the same, fatty acyl chain structure is the key factor that separates membrane states. Increasing chain length and increasing saturation generally enhance interchain packing, making the membrane more ordered, more tightly packed, and less fluid; introducing cis double bonds disrupts chain packing and increases membrane fluidity. Whether the chains are symmetric and whether they are mixed-chain structures also further affect phase behavior. The review by Koynova and Caffrey identifies chain length, degree of unsaturation, and chain asymmetry as important determinants of phosphatidylcholine phase behavior.
This is also why DMPC, DPPC, DSPC, DOPC, and POPC, all phosphatidylcholines, show markedly different experimental behavior at room temperature. These differences are determined by fatty acyl chain length, whether double bonds are present, and whether the structure is mixed-chain.
3.2 The Main Phase Transition Temperature Determines the Membrane State at the Experimental Temperature
The main phase transition temperature, usually denoted as Tm, can be regarded as the reference temperature at which the main bilayer transition occurs. It reflects the temperature position at which the system shifts from a more ordered state to a more fluid state, although the actual transition width and observed behavior are still influenced by lipid purity, salt form, water content, mixing ratio, and thermal history. Experimentally, this value directly determines whether the membrane is relatively rigid and ordered or relatively soft and readily rearranged at the current temperature. In experiments involving film formation, hydration, extrusion, homogenization, or comparison of membrane fluidity, Tm should always be checked first.
Many seemingly scattered problems are, in essence, asking whether the experimental temperature matches the material state. Whether hydration proceeds smoothly, whether extrusion resistance is too high, and why the system behaves very differently at 4°C, 25°C, and 37°C are often directly related to Tm. For the first round of screening of PC lipids, Tm is often already sufficiently informative; but for PE lipids, if the research focus is membrane curvature, fusion, or non-bilayer tendency, their non-bilayer phase behavior should also be considered, and Tm alone should not be used as the sole basis for judgment.
3.3 Fatty Acyl Chain Features and Main Phase Transition Temperatures of Common Representative Phospholipids
Representative phospholipid | Headgroup | Fatty acyl chain feature | Tm (°C, approximate) | Typical tendency at room temperature |
DMPC | PC | 14:0/14:0, short-chain, saturated | 24 | Near the onset of the liquid-crystalline state |
DPPC | PC | 16:0/16:0, medium-chain, saturated | 41 | More ordered at room temperature |
DSPC | PC | 18:0/18:0, long-chain, saturated | 55 | More ordered at both room temperature and physiological temperature |
DOPC | PC | 18:1/18:1, doubly mono-unsaturated chains | -17 | Clearly more fluid at room temperature |
POPC | PC | 16:0/18:1, mixed-chain | -2 | In the liquid-crystalline state at room temperature |
4. Determining the Starting Point for Phospholipid Selection by R&D Task
4.1 When a More Fluid Membrane Is Needed at Room Temperature or Physiological Temperature
When the experimental goal is to obtain a more fluid and more readily rearranged bilayer, the first round of comparison can start with phospholipids that have lower main phase transition temperatures. Phospholipids such as DOPC and POPC are more suitable as starting points because they are usually closer to the liquid-crystalline state at common experimental temperatures and are often used to establish softer, more easily hydrated membrane systems. What should be checked in parallel is not only whether the temperature is above Tm, but also the oxidation sensitivity associated with a higher content of unsaturated chains.
4.2 When a More Ordered and More Rigid Membrane Is Needed
When the goal is greater order, stronger structural retention, or higher thermal stability, it is more appropriate to prioritize long-chain saturated phospholipids. DPPC and DSPC are commonly used as starting points for such systems because they provide clearer high-Tm references. In this case, what needs to be checked in parallel is whether the preparation temperature is sufficient to support hydration, homogenization, and subsequent processing.
4.3 When the Goal Is to Judge Whether Surface Electrostatics and Interfacial Interactions Are the Dominant Factors
When the experimental question centers on adsorption of charged molecules, response to the ionic environment, changes in surface potential, or interfacial recognition behavior, headgroup comparisons are more effective when performed first. A reliable approach is to keep the fatty acyl chain background similar and then compare differences among headgroups such as PC, PE, PG, PS, and PA. This makes it easier to isolate the effect of interfacial electrostatics itself without mixing it together with changes in chain length, unsaturation, or Tm.
4.4 In the First Round of Screening, Change Only One Variable at a Time
In the first round of screening, it is not advisable to change the headgroup, chain length, and unsaturation simultaneously. A more reliable sequence is to first fix the headgroup and compare chain length, saturation, and mixed-chain structure, and then fix the fatty acyl chain and compare headgroups. In this way, the resulting differences are easier to attribute, and it becomes easier to judge whether experimental differences mainly arise from membrane state or from interfacial properties.
4.5 Structural Factors to Prioritize When Selecting Phospholipids by R&D Task
R&D objective | Structural factor to prioritize | Common starting point | Conditions that should be confirmed in parallel |
To obtain a more fluid membrane at room temperature or physiological temperature | Lower Tm, unsaturated chains, or mixed-chain structure | DOPC, POPC | Whether the experimental temperature is above Tm, and whether the oxidation sensitivity of unsaturated chains is acceptable |
To obtain a more ordered and more rigid membrane | Long chains, saturated chains, higher Tm | DPPC, DSPC | Whether the temperatures for hydration, homogenization, and downstream processing are sufficient |
To judge whether surface electrostatics and interfacial interactions are the dominant factors | Headgroup charge and headgroup type | Compare PC, PE, PG, PS, and PA against a similar fatty acyl chain background | Whether salt concentration, divalent ions, and pH will amplify the differences |
To carry out the first round of screening and quickly identify the dominant variable | Change only one variable at a time | First compare chain structure under the same headgroup, then compare headgroups under the same fatty acyl chain | Whether the preparation method, temperature history, and storage conditions are kept consistent |
5. Conditions That Must Be Checked in Parallel During Experiments
The preceding judgments address the question of which class of phospholipid to select first. Once the experiment begins, preparation conditions, pretreatment, and storage conditions must also be checked together. Many problems that seem to arise from material differences actually result from temperature settings, film formation quality, chemical stability, or storage history not being aligned with the material state. Studies on thin-film hydration and extrusion have shown that preparation conditions directly affect subsequent bilayer formation, particle size distribution, and system stability.
5.1 Conditions That Must Be Checked in Parallel During Experiments
Condition | What it directly affects | What to check first in the experiment |
Temperature | Hydration rate, membrane rearrangement, particle-size stability | Whether the preparation temperature matches the Tm of the lipid used |
Organic solvent and hydration step | Film uniformity and whether subsequent hydration proceeds smoothly | Whether the lipid is fully dissolved and whether a uniform thin film is formed after solvent removal |
Oxidation and hydrolysis | Chemical stability and long-term storage performance | Whether the proportion of unsaturated chains is high and whether light protection, oxygen exclusion, and stricter storage conditions are needed |
Storage, freeze-thaw, and reconstitution | Aggregation, fusion, particle-size changes, and state drift | Whether the sample has undergone repeated freeze-thaw cycles and whether the state after reconstitution remains consistent with that of freshly prepared material |
Among these four factors, temperature and thin-film formation quality are the most likely to influence results already at the preparation stage; oxidation and hydrolysis are the core risks for the long-term stability of phospholipids; storage, freeze-thaw, and reconstitution, by contrast, often change particle size, aggregation state, and system reproducibility.
6. Product Navigation Table Related to R&D Judgment for Phospholipid Reagents (Choose Table 1–Table 4 by Research or Experimental Objective)
Research or Experimental Objective | Recommended Table to Consult First | Why This Table Should Be Consulted First | Recommended Table(s) to Cross-Reference | Reason for Cross-Referencing |
To establish a starting point for a basic phospholipid bilayer or liposome system and first distinguish among natural-source, hydrogenated-source, and defined main membrane materials | Table 1 | Table 1 focuses on phosphatidylcholine main membrane materials. It includes natural-source and hydrogenated-source products, as well as defined products with clear differences in chain length, saturation, and mixed-chain structure, making it suitable for first setting up a basic selection framework for main membrane materials | Table 2 | After the main membrane material has been determined, Table 2 can then be consulted to judge whether ethanolamine-type phospholipids need to be introduced to modulate membrane packing, membrane curvature, or fusion behavior |
To compare the effects of chain length, saturation, and mixed-chain structure on membrane fluidity, membrane rigidity, and phase transition temperature | Table 1 | The phosphatidylcholine series in Table 1 provides the most complete gradient of chain structures, making it suitable for building a continuous comparison from short-chain to long-chain, from saturated to unsaturated, and from defined products to natural-source products | Table 2 | Table 2 helps further assess how membrane packing and interfacial behavior change when the headgroup is switched from choline to ethanolamine under a similar chain-structure background |
To study membrane curvature, membrane fusion, membrane rearrangement, or the selection of helper phospholipids in delivery systems | Table 2 | Table 2 is centered on phosphatidylethanolamine, making it easier to first distinguish which products are suitable for modulating membrane curvature, assisting fusion, or altering membrane rearrangement capability | Table 1 | Returning to Table 1 after reviewing Table 2 makes it easier to combine ethanolamine-type helper phospholipids with choline-type main membrane materials and form a clearer main/helper membrane material combination |
To examine how surface electrostatics, salt response, and interactions with charged molecules change after introducing an anionic headgroup | Table 3 | Table 3 focuses on phosphatidic acid, phosphatidylglycerol, and phosphatidylserine, making it suitable for first judging how membrane surface properties and dispersion behavior change after the introduction of a negatively charged headgroup | Table 1 | Establishing a baseline first with the neutral main membrane materials in Table 1, and then cross-referencing Table 3, makes it easier to isolate the differences brought about by the introduction of an anionic headgroup itself |
To distinguish among phosphatidic acid, phosphatidylglycerol, and phosphatidylserine as different anionic headgroups, rather than treating them all simply as negatively charged phospholipids | Table 3 | Table 3 places these three commonly used anionic headgroups in one group, making it suitable for directly comparing how differences in headgroup type affect interfacial properties, ion binding, and membrane state | Table 4 | If the experiment also needs to include the inositol headgroup in comparisons among anionic phospholipids, cross-referencing Table 4 provides a more complete headgroup dimension |
To include the inositol headgroup in the study and determine whether natural-source phosphatidylinositol is suitable as a starting point for PI-containing membrane systems | Table 4 | Table 4 focuses on natural-source phosphatidylinositol, making it suitable for first establishing a starting point for the use of inositol-type anionic headgroups and for judging whether PI should be included as a supplementary headgroup in subsequent membrane-system studies | Table 3 | Table 3 supplements the comparison with other anionic headgroups, making it easier to compare the differences between the inositol headgroup and glycerol, serine, and phosphatidic acid headgroups; if further separation of chain-structure and thermal-behavior effects is needed, the study should then move to more clearly defined systems |
To compare headgroups at the same chain length and observe how headgroup changes themselves affect membrane properties | Table 1 | The phosphatidylcholine lipids in Table 1 can serve as the neutral starting point for same-chain-length comparisons and are suitable for first establishing a basic reference | Tables 2 and 3 | By then cross-referencing Tables 2 and 3, ethanolamine, glycerol, serine, and phosphatidic acid headgroups under similar chain-length conditions can be introduced step by step to form a more complete headgroup comparison set |
To begin exploration from natural-source systems and then gradually move to structurally defined phospholipids for refined screening | Table 1 | Table 1 includes natural-source, hydrogenated-source, and defined phosphatidylcholine products at the same time, making it suitable for starting with products that are easier to use for establishing a system and then moving on to control substances with clearly defined chain structures | Tables 3 and 4 | After a basic membrane system has been established, anionic phospholipids and inositol-type phospholipids can then be introduced through cross-referencing to continue bringing surface electrostatics and headgroup effects into subsequent screening |
Table 1 | Phosphatidylcholine (PC) Class: Natural-Source, Hydrogenated-Source, and Defined Chain-Structure Comparisons
Category | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product Features and Applications |
Medium-chain saturated PC reference | 63-89-8 | DPPC | Injection grade | Commonly used as a benchmark medium-chain saturated phosphatidylcholine. Suitable for comparing membrane rigidity, phase transition temperature, and bilayer stability, and also commonly used in liposome and pulmonary surfactant model formulation studies. | |
Natural-source PC | 97281-47-5 | L-α-phosphatidylcholine (Soy) | Natural, ≥99% | Commonly used in natural-source phospholipid systems, basic liposome film formation, and formulation screening. Suitable for examining how natural mixed fatty acyl chain compositions affect membrane fluidity and encapsulation performance. | |
Natural-source PC | 97281-44-2 | L-α-phosphatidylcholine (95%) (Egg, Chicken) | Natural, ≥95% | Commonly used in natural-source lecithin systems, basic film formation, and dispersion-system exploration. Suitable for comparing source differences and chain-composition differences against soybean-derived and defined phospholipids. | |
Hydrogenated natural-source PC | 97281-48-6 | Phosphatidylcholine, hydrogenated from Non-GMO Soybean(HSPC) | Natural, ≥90% | Commonly used in highly saturated, highly ordered membrane systems and drug delivery formulations. Suitable for comparing membrane stability, phase transition temperature, and leakage control performance after hydrogenation. | |
Short-chain saturated PC reference | 18194-24-6 | DMPC | Reagent grade | Commonly used as a saturated phosphatidylcholine control with a relatively low phase transition temperature. Suitable for studying changes in bilayer fluidity, hydration behavior, and temperature response after chain shortening. | |
Doubly monounsaturated PC reference | 4235-95-4 | 1,2-dioleoyl-sn-glycero-3-phosphocholine | Moligand™,≥99% | Commonly used as a representative low-phase-transition-temperature, highly fluid membrane lipid. Suitable for comparing the effects of unsaturated chains on membrane flexibility, rearrangement rate, and film formation behavior at room temperature. | |
Long-chain saturated PC reference | 816-94-4 | 1,2-distearoyl-sn-glycero-3-phosphocholine （DSPC） | Moligand™, ≥99% | Commonly used as a representative phosphatidylcholine with a high phase transition temperature and high rigidity. Suitable for comparing the effects of long-chain saturated fatty acyl chains on membrane compactness, thermal stability, and temperature-controlled processing conditions. | |
Shorter-chain saturated PC reference | 18194-25-7 | 1,2-dilauroyl-sn-glycero-3-phosphocholine | ≥99% | Suitable for establishing a shorter-chain saturated phosphatidylcholine reference, facilitating systematic comparison of the continuous effects of chain-length variation on phase transition temperature, bilayer thickness, and membrane fluidity. | |
Mixed-chain PC reference | 26853-31-6 | 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine（POPC） | ≥99% | Commonly used as a representative mixed-chain phosphatidylcholine. Suitable for simulating relatively fluid bilayer membranes at room temperature and for comparing differences between mixed-chain structures and fully saturated or fully unsaturated structures. | |
Hydrogenated natural-source PC | 97281-45-3 | L-α-phosphatidylcholine, hydrogenated (Egg, Chicken) | ≥99% | Commonly used in highly saturated natural-source phospholipid systems. Suitable for comparison with non-hydrogenated egg-derived phosphatidylcholine to examine changes in membrane order and stability after hydrogenation. | |
Mixed-chain PC reference | 56421-10-4 | 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine | ≥98% | Suitable for use as a mixed-chain phosphatidylcholine control, comparing membrane order and fluidity when one long saturated fatty acyl chain coexists with one unsaturated fatty acyl chain. |
Table 2 | Phosphatidylethanolamine (PE) Class: Headgroup Comparison, Membrane Curvature, and Fusion Behavior Research
Category | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product Features and Applications |
Doubly monounsaturated PE reference | 4004-05-1 | DOPE | Pharmaceutical grade | Commonly used for studying membrane curvature, membrane fusion, and the tendency toward non-bilayer structures. Also often used as a helper phospholipid in delivery systems to regulate membrane flexibility and rearrangement capability. | |
Medium-chain saturated PE reference | 923-61-5 | DPPE | Reagent grade | Suitable for comparing headgroup differences against phosphatidylcholine, phosphatidylglycerol, and phosphatidylserine of the same chain length, in order to observe the effects of the ethanolamine headgroup on membrane packing and interfacial properties. | |
Long-chain saturated PE reference | 1069-79-0 | DSPE | Reagent grade | Commonly used as a benchmark ethanolamine-type phospholipid with a high phase transition temperature. Suitable for studying membrane order, thermal response, and headgroup effects under long-chain saturated conditions. | |
Short-chain saturated PE reference | 998-07-2 | DMPE | Reagent grade | Suitable for constructing an ethanolamine-type phospholipid comparison system with a shorter chain length, in order to compare the combined effects of chain-length variation on membrane state and headgroup effects. | |
Mixed-chain PE reference | 26662-94-2 | 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine(POPE) | Moligand™,≥95% | Suitable for research on mixed-chain ethanolamine-type phospholipids, comparing how a monounsaturated mixed-chain structure affects membrane curvature, fluidity, and interfacial packing. |
Table 3 | Anionic Phospholipids: Phosphatidic Acid (PA), Phosphatidylglycerol (PG), and Phosphatidylserine (PS)
Category | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product Features and Applications |
Medium-chain saturated PA reference | 169051-60-9 | DPPA-Na | Pharmaceutical grade | Commonly used as an acidic anionic phospholipid control. Suitable for studying the effects of negatively charged headgroups on membrane surface electrostatics, ion binding, and membrane compactness. | |
Short-chain saturated PG reference | 200880-40-6 | DMPG-Na | Pharmaceutical grade | Suitable for headgroup comparison against phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine of the same chain length, and for observing interfacial changes after the introduction of negative charge. | |
Medium-chain saturated PS reference | 145849-32-7 | DPPS | Reagent grade | Commonly used as a benchmark serine-type anionic phospholipid. Suitable for studying the effects of headgroup charge, hydrogen-bonding capability, and protein interactions on membrane behavior. | |
Doubly monounsaturated PS reference | 90693-88-2 | 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (sodium salt)（DOPS） | Moligand™, ≥99% | Commonly used in relatively fluid anionic membrane systems and serine-headgroup comparison experiments. Suitable for examining the combined effects of surface negative charge and membrane fluidity under low-phase-transition-temperature conditions. | |
Medium-chain saturated PG reference | 200880-41-7 | D130350 | 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt)(DPPG) | ≥99% | Commonly used as a representative saturated anionic phosphatidylglycerol. Suitable for comparing changes in membrane surface electrostatics, membrane stability, and dispersion behavior after introduction of the glycerol headgroup. |
Doubly monounsaturated PG reference | 67254-28-8 | 1,2-Dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt | ≥99% | Commonly used in relatively fluid anionic membrane systems. Suitable for comparing the effects of glycerol-type anionic headgroups on surface electrostatics and membrane rearrangement under unsaturated-chain conditions. | |
Doubly unsaturated PA reference | 108392-02-5 | 1,2-dioleoyl-sn-glycero-3-phosphate (sodium salt) (18:1 PA) | ≥99% | Suitable for research on relatively fluid acidic anionic membranes and for examining the effects of the phosphatidic acid headgroup on membrane curvature, ionic response, and surface charge under unsaturated-chain conditions. | |
Long-chain saturated PS reference | 321595-13-5 | 1,2-distearoyl-sn-glycero-3-phospho-L-serine (sodium salt) | ≥99% | Commonly used as an anionic membrane control with a high phase transition temperature. Suitable for studying the effects of the serine headgroup on membrane order and surface interactions under long-chain saturated conditions. | |
Mixed-chain PG reference | 268550-95-4 | 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt)(POPG sodium salt) | ≥99% | Suitable for research on mixed-chain anionic membranes, comparing the combined effects of glycerol-type headgroups on membrane fluidity and surface negative charge under monounsaturated mixed-chain conditions. | |
Short-chain saturated PA reference | 80724-31-8 | 1,2-dimyristoyl-sn-glycero-3-phosphate (sodium salt) | ≥98% | Suitable for constructing a shorter-chain acidic anionic phospholipid reference, facilitating comparison of how chain-length variation affects phosphatidic acid headgroup behavior and membrane state. | |
Short-chain saturated PS reference | 105405-50-3 | 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (sodium salt) | ≥97% | Suitable for use as a shorter-chain serine-type anionic phospholipid control, comparing how reduced chain length changes surface negative charge and membrane fluidity. | |
Mixed-chain PS reference | 321863-21-2 | 16:0-18:1 PS (POPS) | ≥97% | Commonly used in research on mixed-chain serine-type anionic membranes. Suitable for comparing headgroup charge, membrane flexibility, and interfacial recognition behavior under a monounsaturated mixed-chain structure. |
Table 4 | Phosphatidylinositol (PI) Class: Supplementary Comparison of Natural-Source Inositol-Type Anionic Headgroups
Category | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product Features and Applications |
Natural-source PI | 383907-33-3 | L-α-phosphatidylinositol (Liver, Bovine) (sodium salt) | ≥99% | Commonly used to introduce inositol-type anionic headgroups into membrane systems and suitable as a research starting point for natural-source phosphatidylinositol; if strict comparison of chain structure or thermal behavior is required, the study should shift to more structurally defined phospholipid systems. | |
Natural-source PI | 383907-36-6 | Phosphatidylinositol (soy) (sodium salt) | ≥98%,50 mg/mL in chloroform | Suitable for film formation and formulation exploration of natural-source phosphatidylinositol and can serve as a starting point for introducing the inositol headgroup into membrane systems; it is more suitable for preliminary screening, and if further comparison of chain structure or thermal behavior is needed, the study should move to defined phospholipid systems. |
Note: The above are representative Aladdin products. For more product specifications, search the Aladdin official website using the product name/CAS/catalog number.
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