photosensitization, the process of initiating a reaction through the use of a substance capable of absorbing light and transferring the energy to the desired reactants.

What is photosensitizer in chemistry?

Photosensitizers are molecules that can be activated by light in order to generate ROS that can damage cell structures from microorganisms or from diseased mammalian cells leading to cell death.

What do you mean by photosensitizer explain with example?

Photosensitization is a reaction to light that is mediated by a light-absorbing molecule, which is not the ultimate target. Photosensitization can involve reactions within living cells or tissues, or they can occur in pure chemical systems. In photobiology, we are concerned with the reactions in living systems.

What is photosensitizer?

Definition. Photosensitizers are molecules which absorb light (hν) and transfer the energy from the incident light into another nearby molecule. This light is often within the visible spectrum or infrared spectrum, as any higher energy electromagnetic radiation may result in the photoelectric effect.

What is a good photosensitizer?

A good photosensitizer should absorb photons efficiently (i.e., high absorption coefficient), have a high quantum yield of triplet formation, and the triplet state should be long lived in order to have time to react with neighbouring target molecules. ... Even dimers of the photosensitizer can be photochemically inactive.

Photochemistry Part 2 : What is Photosensitization?

43 related questions found

Is Au a photosensitizer?

Upon complexation with Au(I), a photoinactive BODIPY derivative was transformed into a highly photoactive triplet sensitizer. Along with high efficiency in singlet oxygen generation (Φ_Δ = 0.84), the new BODIPY–Au(I) skeleton showed excellent photocytotoxic activity against cancer cell lines (EC₅₀ = 2.5 nM).

Is Mercury a photosensitizer?

A commonly used sensitizer is mercury, which absorbs radiation at 1849 and 2537 angstroms; these are the wavelengths of light produced in high-intensity mercury lamps.

What is equine Photosensitization?

Photosensitization is a condition in which skin becomes overly sensitive to ultraviolet light (sunlight). This condition is not sunburn, although the difference can be difficult to distinguish.

What is photosensitizers in photodynamic therapy?

Photodynamic therapy (PDT) is based on the use of light-sensitive molecules called photosensitizers. Photoactivation causes the formation of singlet oxygen, which produces peroxidative reactions that can cause cell damage and death.

Is chlorophyll a photosensitizer?

Chlorophyll has been experimented to function as a photosensitizer in dye-sensitized solar cells (DSSCs) as DSSCs mimic the photosynthesis process in green plants. ... The dye absorbs light, which is transformed into electricity.

What is photosensitizer in chemistry class 12?

It is a chemical substance which is added to the reaction mixture to initiate a photochemical reaction without undergoing any chemical change itself and the phenomenon is known as photosensitisation.

What is photosensitized reaction and photosensitizer?

A reaction is considered photosensitized when an excited molecule (the donor or photosensitizer) induces photochemical reactions in molecules (the acceptor or quencher) that are not photochemically reactive by themselves, i.e., do not absorb light in the considered wavelength range.

What are the two types of photosensitizing reactions?

Photosensitized reactions involving oxygen are framed as either as type I or type II. Type I and II photosensitized oxidation reactions require oxygen as a reagent. The type I and II photosensitized mechanisms apply to photoreactions including initial electron or hydrogen atom abstraction as an oxidizing step.

What is the best example of photosensitizer?

In the second pathway light is absorbed by certain molecules, so-called photosensitizers (Sen), which can transfer the absorbed light energy to other molecules (substrates or targets (T)).

What is the main difference between a photosensitizer and a catalyst?

A catalyst does not change in itself or being consumed in the overall chemical reaction. This definition includes photosensitization, a process by which a photochemical alteration occurs in one molecular entity as a result of initial absorption of radiation by another molecular entity called the photosensitized.

Which of the following is a photosensitizer?

Chlorophyll acts as a photosensitizer during photosynthesis.

Why are photosensitizers added to polymers?

Photosensitizers can induce the generation of singlet oxygen (¹O₂) under light irradiation. It is known that ¹O₂ is very reactive and can function as a strong oxidant. ... Most of the reported photosensitizers are small conjugated molecules,¹ whereas polymeric analogs are rarely explored.

What is Chlorin e6?

Chlorin e6 (Ce6) is a second-generation photosensitizer with antitumor activity when used in conjunction with irradiation. In a mouse model of implanted fibrosarcoma, Ce6 (2.5-10 mg/kg, i.v. with irradiation at 50-200 J/cm2) led to complete tumor loss... 100 mg.

What is the role of Photosensitization in the modern medicine?

Photosensitization allows a nonabsorbing acceptor species to be excited in the presence of a light-absorbing donor molecule.

What causes hives in horses?

The most common causes of hives in horses are insect bites or stings, medications, and exposure to allergens. Other potential causes include vasculitis (inflammation of the blood vessels of the skin), food allergy, ringworm.

Can horses be allergic to the sun?

True allergy, or hypersensitivity, to the sun is rare in horses. More common is "photosensitivity," sun-related skin injury that's triggered by chemical imbalances in the body. Forage plants are one possible culprit in the process but certain drugs or underlying liver disease may also be factors.

What causes horse uveitis?

Equine recurrent uveitis is hypothesized to be a complex autoimmune disease influenced by both genetic and environmental factors. Appaloosa horses are particularly susceptible to ERU, and in particular to bilateral disease, which suggests that genetics plays a significant role in ERU risk in this breed.

What is mechanism of isotopic study?

In this paper, simple theory for the application of isotope effects to reaction mechanism is developed, and applied to organic reactions and those catalyzed by enzymes. Techniques used to measure isotope effects depend somewhat on the isotope used, that is radioisotope vs. stable isotope, or hydrogen isotope vs.

What is Photosensitization discuss its mechanism?

Photosensitization is a condition caused by the accumulation of a photodynamic agent in the skin that sensitizes it to ultraviolet radiation (Fowler 1993). Exposure of nonpigmented skin to UV radiation (e.g., the sun) results in dermatonecrosis.

What happens in Photosensitization?

In photosensitization, unstable, high-energy molecules are formed when photons react with a photodynamic agent. These high-energy molecules initiate reactions with substrate molecules of the skin, causing the release of free radicals that in turn result in increased permeability of outer cell and lysosomal membranes.