Thread by @NotTheMacAnon1

Just putting this out there

Gram-negative bacteria can hinder cationic liposomes in several ways, primarily by interacting with the liposomes' positively charged components, which can lead to liposome aggregation, reduced membrane fusion, and lower drug delivery efficiency. Specifically, liposomes may become immobilized by components of the lipopolysaccharide (LPS) layer, while bacterial enzymes or high salt concentrations in the surrounding medium can destabilize the liposomes, preventing them from effectively interacting with and fusing with the bacterial membranes

Foods that can be sources of Gram-negative bacteria include vegetables and fruits (especially when consumed raw), dairy products like milk and cheese, and meats. These bacteria are ubiquitous, found in the environment, and can contaminate the food chain through various pathways, such as direct contact with contaminated surfaces or through animal and human intestinal tracts

•The bacterial environment, particularly components in the growth medium or bacterial enzymes, can destabilize the liposomes, causing them to disrupt or aggregate.
•High salt concentrations can also reduce the electrostatic interaction, further interfering with the liposomes' ability to function as drug carriers.

•While cationic liposomes are designed to destabilize membranes, the presence of the LPS layer in Gram-negative bacteria can reduce the effectiveness of this process.

Logically.

anionic and cationic liposomes will interact via electrostatic attraction, forming ion-pairs that can neutralize each other's charge,

Note:

Milk anionic lipids are polar lipids like phosphatidylserine (PS) and phosphatidylinositol (PI), which carry a negative charge. They are found in the milk fat globule membrane (MFGM) and contribute to its structural organization, playing roles in cellular signaling and potentially impacting health, such as cholesterol absorption and intestinal health. While quantitatively minor compared to other milk polar lipids, their presence is significant for the functionality of the MFGM and its bio-benefits.

Eating a diet rich in fruits and vegetables provides antioxidants that donate electrons to free radicals, stabilizing them without becoming unstable themselves.

This imbalance can result from increased free radical production

•Certain nanoparticles, particularly those with redox-active metal oxides (like copper and titanium), can catalyze reactions like the Fentonand Haber-Weiss cycles, producing highly reactive free radicals such as hydroxyl radicals (•OH) and superoxide (•O2-).
•Surface-Induced Reactions:Free radicals can be bound to the nanoparticle surface and react with oxidants, leading to the formation of new reactive oxygen species (ROS).
•Ion Release: For some materials, like silver nanoparticles (Ag-NPs), the release of ions (e.g., Ag+) can react with molecular oxygen, generating ROS and causing oxidative stress.

Titanium dioxide (TiO2), also known as E171, is a white food coloring found in a variety of products like candies, chocolates, chewing gum, and pastries. It also appears in dressings, creams, desserts, and some cheeses. While it's approved in the US, it was banned in the EU in 2022 due to safety concerns, and Mars phased it out of their Skittles in 2025. You can find it listed as "artificial color" on ingredient lists, or sometimes not at all, so it's best to check labels carefully or stick to less processed foods to avoid it

So I checked the label.

TiO2 quantum dot (QD) labelling refers to methods used to attach fluorescent or other signaling moieties to titanium dioxide (TiO2) quantum dots for applications like biosensing and imaging. Strategies involve using established chemistries like Click chemistry(copper-catalyzed azide-alkyne cycloaddition) to conjugate dyes to functionalized TiO2 QDs, or direct conjugation of fluorescent biotinand streptavidin. These labelled TiO2 QDs serve as highly sensitive probes, providing unique optical signals for detecting and visualizing biological molecules and processes with enhanced photostability and long-term imaging capabilities.

The generation of radical species in aqueous solution by photoirradiation of CdS, CdSe, and CdsE/ZnS quantum dots (QD), was investigated. Two independent methods such as EPR spectroscopy and a radical-specific highly sensitive fluorimetric assay was used to measure and identify any photogenerated radical species. CdS QDs were synthesized in a reverse-micellar medium while the CdSe QDs were synthesized according to the method of Peng and Peng. The CdSe QDs were then coated with hexamethyl-disilathiane and diethylzinc to produce CdSe/ZnS QDs. A fluorescence spectroscopy assay based on the specific trapping of hydroxyl radical by terepthalate anions was used to verify the hypothesis drawn from the EPR data. It was found that semiconductor quantum dots produce free radicals upon UV irradiation in aqueous solution with two independent methods. The results show that with two independent methods that semiconductor quantum dots produce free radicals upon UV radiation in aqueous solutions.

Tio2 quantum dot (QD) electron transfer refers to the process where electrons are excited within semiconductor QDs and then transferred to TiO2, a common metal oxide, leading to enhanced photocatalytic activity in composite materials. The transfer is influenced by the QD's size and surface properties, the concentration of defects in the TiO2, and the presence of interfacial linkers, all of which can be tuned to optimize the process and improve the efficiency of applications like solar energy conversion.

1Photoexcitation: When a QD absorbs light, an electron is excited to a higher energy level within the QD's conduction band.
2Electron Injection: This excited electron can then be injected into the conduction band of the adjacent TiO2, a process known as electron transfer.

TiO2 QDs can also be integrated into other catalysts, such as cobalt phosphide (CoP), to modulate electron transfer and prevent overoxidation of the catalyst

overoxidation (usually uncountable, pluraloveroxidations)
1Excessive oxidation (or to a greater than normal extent)

Oxidation refers to reactions where molecules lose electrons, which can create unstable, highly reactive "free radicals" with unpaired electrons

Overoxidation of Reactive Oxygen Species (ROS) can be a cause of lipid peroxidation, a destructive process where ROS damage lipids in cell membranes. When antioxidant defenses are overwhelmed by high levels of ROS, these reactive molecules attack polyunsaturated fatty acids (PUFAs) in cell membranes, initiating a self-propagating chain reaction. This process damages membrane structures, alters membrane properties, and generates toxic byproducts like aldehydes, leading to cell injury and playing a role in various diseases. 
How Overoxidation Leads to Lipid Peroxidation:
1Oxidative Stress: When the balance between prooxidants (like ROS) and antioxidants favors prooxidants, it results in oxidative stress.
2ROS Attack: In an overoxidized state, high levels of ROS (such as the hydroxyl radical) can abstract a hydrogen atom from a PUFA in the cell membrane, creating a lipid radical.
3Propagation: The lipid radical then reacts with molecular oxygen, forming a lipid hydroperoxyl radical (LOO•), which can then abstract a hydrogen from another PUFA, propagating the chain reaction and forming a lipid hydroperoxide (LOOH).
4Consequences: This chain reaction continues, leading to extensive damage to the cell membrane and the formation of harmful byproducts like malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE). 
Impact of Lipid Peroxidation:

Membrane Damage:
The altered structure and function of the cell membrane can lead to a loss of cell integrity and changes in permeability. 
Cellular Dysfunction:
Oxidized lipids and their breakdown products can affect protein and DNA function, contributing to inflammation and other pathological processes. 
Disease Involvement:
Excessive lipid peroxidation is linked to various diseases, including atherosclerosis, neurodegenerative diseases, and cancer. It is also a key feature of specific cell death pathways, such as ferroptosis.

Overoxidation of food occurs when lipid peroxidation continues after the formation of detrimental byproducts, accelerating food spoilage by increasing off-flavors, nutrient loss, and the accumulation of potentially harmful compounds. This process degrades unsaturated fatty acids through free-radical chain reactions, leading to rancidity in fats and oils and negatively impacting the quality, stability, nutrition, and safety of lipid-containing foods like meat, fish, and processed goods. 
What is Lipid Peroxidation?

A Degradation Process:
Lipid peroxidation is the oxidation of lipids, a type of fat, primarily involving unsaturated fatty acids in foods. 
Free Radical Chain Reaction:
It's a chain reaction initiated by free radicals that reacts with lipids, producing lipid hydroperoxides and then breaking them down into smaller, volatile molecules like aldehydes and ketones. 
A Key Quality Issue:
Lipid oxidation is a major cause of food spoilage, leading to:
◦Off-flavors and aromas: The volatile compounds formed can give food a rancid, unpleasant taste and smell.
◦Nutrient loss: Oxidation can reduce the nutritional value of food.

Lipid peroxidation, the oxidative damage to fats in cell membranes, is an early and critical feature of Alzheimer's disease (AD) and contributes to its progression and severity, as indicated by elevated biomarkers in postmortem brains and cerebrospinal fluid (CSF). This process involves the damaging of polyunsaturated fatty acids (PUFAs) by free radicals, creating products like isoprostanes and 4-HNE, which can then covalently bind to proteins, impairing their function and further contributing to neurodegeneration. Identifying these biomarkers could aid in early diagnosis and development of targeted therapies. 
What is Lipid Peroxidation?

Definition
: Lipid peroxidation is a free radical-mediated chain reaction that damages lipids, which are essential components of cell membranes, especially in the brain.

Yes, quantum dots (QDs) can cross the blood-brain barrier (BBB), with some evidence suggesting they can induce disruption.

Yes, blood-brain barrier (BBB) leakage is associated with hydrocephalus, particularly in cases of idiopathic normal pressure hydrocephalus (iNPH), where it indicates a severe breach of the barrier's integrity and can lead to the accumulation of neurotoxic substances in the brain. While the exact relationship is complex and may differ in various forms of hydrocephalus, a disrupted BBB contributes to the neurological damage and can be a key factor in the disease's progression and outcomes.

A compromised BBB can fail to prevent neurotoxic substances from entering the brain, and the resulting accumulation can damage brain tissue and contribute to hydrocephalus. 
Inflammation:
The breakdown of the BBB can trigger an inflammatory response in the brain, with the release of inflammatory cytokines, which can further damage the BBB and promote neurodegeneration. 
Association with iNPH:
In iNPH, researchers have observed significant fibrinogen extravasation (a sign of BBB leakage) in the cerebral cortex. This leakage is correlated with the degree of astrogliosis (reactive astrocytes), a common feature in hydrocephalus. 
Cerebral small vessel disease (CSVD):
CSVD, which involves damage to small blood vessels in the brain, is also common in iNPH and can contribute to BBB dysfunction and increased leakage. 
Important Considerations:

Complexity of the relationship:
The relationship between BBB integrity and hydrocephalus is complex, and inconsistencies exist in the literature. 
Different types of hydrocephalus:
The role of BBB integrity may differ depending on the specific type and cause of hydrocephalus. For example, while BBB disruption is noted in iNPH, it's not always a primary feature in all forms. 
Further research needed:
More sensitive and reliable markers are needed to fully understand the role and variability of BBB leakage in hydrocephalus.

Hydrocephalus is a condition characterized by excess cerebrospinal fluid (CSF) in the brain, leading to a buildup of pressure that can cause various symptoms like headaches, vision problems, and impaired balance, along with developmental issues in children

🚩

@threadreaderapp

Unroll