Treating cancer with light-sensitive nanoscale biomaterials
Combining nanotechnology with laser light creates powerful effect on
cancer cells

Date:
March 15, 2022
Source:
American Institute of Physics
Summary:
Treating cancer and other diseases with laser light is not currently
considered routine, but new approaches using nanoparticles show
some promise in improving existing techniques. Researchers review
the status of the field and by combining photothermal therapy or
photodynamic therapy with nanomaterials, they have been able to
apply these types of phototherapies while also delivering drugs
to sites in the body that are otherwise inaccessible. It is also
possible to combine PTT and PDT into a single treatment, creating
an even more powerful treatment method.



FULL STORY ========================================================================== Treating cancer and other diseases with laser light is not currently
considered routine in the clinical setting, but new approaches using nanoparticles show some promise in improving existing techniques.


==========================================================================
One technique, known as photothermal therapy (PTT), converts laser
light into heat that can target and kill tumor cells. Another technique, photodynamic therapy (PDT), uses laser light to generate reactive oxygen species (ROS), such as hydroxyl radicals, singlet oxygen, superoxide
radicals, and hydrogen peroxide, which can wreak devastation on tumor
cells.

InApplied Physics Reviews, by AIP Publishing, a multinational
team of researchers reviews the current status of the field of nanoparticle-enhanced PDT and PTT and focuses on combining the two
techniques to achieve the highest level of treatment efficiency.

By combining PTT or PDT with nanomaterials, investigators have been able
to apply these types of phototherapies while also delivering drugs to
sites in the body that are otherwise inaccessible. It is also possible
to combine PTT and PDT into a single treatment, creating an even more
powerful treatment method.

The surface of the nanoparticle can be modified to attach a photosensitive molecule to the surface. This allows the absorption of light at a
particular wavelength. In the PTT method, this light is converted to
heat. In PDT, the light creates ROS. For PDT to be successful, sufficient ambient oxygen must be present to produce enough ROS to kill tumor cells.

"In cancer therapies using this strategy, the penetration depth of
laser light into the tissues is critical in determining the therapeutic efficiency," said author Masoud Mozafari, from the Iran University of
Medical Sciences.

Factors that control the penetration depth include the shape of the
beam, wavelength of the light, intensity of the laser, and the radius
of the beam.

A powerful approach is to combine PDT with traditional medical treatments,
such as chemotherapy, to create photodynamic antibacterial chemotherapy.

The nanoparticles can be used to deliver chemotherapeutic agents or
antibiotics to the tumor site. When light is applied, generating ROS
molecules in the tumor and killing both tumor cells and bacteria, the antibiotics can be released to prevent infection in the treated area.

Other modifications to the nanoparticle surface could allow it to cross
the blood-brain barrier so that brain tumors can be treated.

One set of studies reviewed in this work involved gold nanorods that had
a glycoprotein from the rabies virus attached to their surface. Since
this virus naturally infects the brain, the gold nanorods were able to penetrate the blood-brain barrier and target the brain tumor. Applying
light from a laser then allowed the nanorods to generate localized heat, killing the tumor cells.

These techniques can also be used to treat other medical issues,
such as atherosclerosis, scar removal, abscesses, nonhealing ulcers,
or dental infections.


========================================================================== Story Source: Materials provided by American_Institute_of_Physics. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Behzad Nasseri, Effat Alizadeh, Farhad Bani, Soodabeh Davaran,
Abolfazl
Akbarzadeh, Navid Rabiee, Ali Bahadori, Mojtaba Ziaei, Mojtaba
Bagherzadeh, Mohammad Reza Saeb, Masoud Mozafari, Michael
R. Hamblin.

Nanomaterials for photothermal and photodynamic cancer
therapy. Applied Physics Reviews, 2022; 9 (1): 011317 DOI:
10.1063/5.0047672 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220315112957.htm

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