Membrane intercalation enhances photodynamic bacteria inactivation

November 06, 2019

Bacterial infections pose a threat to human health. Now, with increasing antibiotic resistance, such infections may again ravage humanity as they did in the pre-antibiotic era. Scientists are thus seeking new, non-antibiotic means to combat bacterial infection.

One promising strategy is photodynamic inactivation (PDI). It uses photosensitizers to generate reactive oxygen species (ROS) that damage bioactive substances in the cell membrane, thus causing irreversible bacterial death in the presence of light and O2. Unfortunately, ROS has a short half-life and reaction radius. As a result, a big challenge for PDI is how to enhance membrane intercalation.

Recently, researchers from the Technical Institute of Physics and Chemistry (TIPC) of the Chinese Academy of Sciences, Shanghai Jiao Tong University and the University of Utah reported their work on achieving enhanced membrane intercalation.

In this work, the scientists arranged for a peptide-decorated cell-penetrating virus coat protein (TAT-TMVCP) and an organoplatinum metallacycle (TPE-Pt-MC), which acts as a photosynthesizer with aggregation-induced emission, to self-assemble through electrostatic interaction.

In the "new" assembly, the photosensitizer provides ROS-generation capacity. The peptide exposed on the surface provides membrane-intercalating capacity.

The researchers discovered that the assembly achieved significantly enhanced PDI efficiency against E. coli and S. aureus, especially against gram-negative E. coli. The assembly decreased E. coli's survival rate from 55% in the dark to nearly 0% upon light irradiation.

This study has wide implications, ranging from improving PDI efficiency to generating multifunctional nanomaterials.
The results, entitled "Membrane intercalation-enhanced photodynamic inactivation of bacteria by a metallacycle and TAT-decorated virus coat protein", were published in PNAS on November 4th 2019.

This research was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the National Institutes of Health of the U.S., and the Beijing Municipal Natural Science Foundation, among others.

Chinese Academy of Sciences Headquarters

Related Physics Articles from Brightsurf:

Helium, a little atom for big physics
Helium is the simplest multi-body atom. Its energy levels can be calculated with extremely high precision only relying on a few fundamental physical constants and the quantum electrodynamics (QED) theory.

Hyperbolic metamaterials exhibit 2T physics
According to Igor Smolyaninov of the University of Maryland, ''One of the more unusual applications of metamaterials was a theoretical proposal to construct a physical system that would exhibit two-time physics behavior on small scales.''

Challenges and opportunities for women in physics
Women in the United States hold fewer than 25% of bachelor's degrees, 20% of doctoral degrees and 19% of faculty positions in physics.

Indeterminist physics for an open world
Classical physics is characterized by the equations describing the world.

Leptons help in tracking new physics
Electrons with 'colleagues' -- other leptons - are one of many products of collisions observed in the LHCb experiment at the Large Hadron Collider.

Has physics ever been deterministic?
Researchers from the Austrian Academy of Sciences, the University of Vienna and the University of Geneva, have proposed a new interpretation of classical physics without real numbers.

Twisted physics
A new study in the journal Nature shows that superconductivity in bilayer graphene can be turned on or off with a small voltage change, increasing its usefulness for electronic devices.

Physics vs. asthma
A research team from the MIPT Center for Molecular Mechanisms of Aging and Age-Related Diseases has collaborated with colleagues from the U.S., Canada, France, and Germany to determine the spatial structure of the CysLT1 receptor.

2D topological physics from shaking a 1D wire
Published in Physical Review X, this new study propose a realistic scheme to observe a 'cold-atomic quantum Hall effect.'

Helping physics teachers who don't know physics
A shortage of high school physics teachers has led to teachers with little-to-no training taking over physics classrooms, reports show.

Read More: Physics News and Physics Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to