In what reads like science fiction, a new study published in the journal ACS Central

Science reports the development of bandages that

detect the presence of bacteria in wounds and change color, depending on whether they are

drug-sensitive or drug-resistant. This is an important step in helping patients recover

better. There are also bandages for specific uses, like

orthopedic bandage,

and fixation bandage.
Drug resistance – the problem
Drug resistance is among the greatest threats to worldwide health. If bacterial

infections could be sensed early enough to treat them before they take a hold on the

patient, it would help avoid serious infections. And if the bacteria resist the

antibiotic, being able to detect this would be crucial in switching drugs to arrest the

infection before it spreads.
At present, the methods of detecting antibiotic resistance are expensive, require

professional expertise, and take too much time. Moreover, using antibiotics for

infections that are resistant to them promotes even more drug resistance.
Colorimetric methods to the rescue
The new study describes a way of doing just this, based on a color-changing material.

Described as “a portable paper-based band-aid (PBA)”, it is a colorimetric way of

sensing and treating sensitive bacterial infections while signaling the presence of

drug-resistant bacteria as well.
Early detection of infection in this study exploits the microenvironment of bacterial

growth, which includes an acidic pH, various toxins and enzymes. Acidity is an easy way

to track the presence of pathogenic bacteria because it is due to their breakdown of

glucose. Drug resistance, on the other hand, depends on the presence of the beta-

lactamase and similar enzymes. The presence of beta-lactamase is a widely used indicator

of bacterial antibiotic resistance because it denotes resistance to the extremely common

beta-lactam antibiotics.
Once drug resistance has been identified, photodynamic therapy and other similar

treatments have been adopted to increase the level of reactive oxygen species (ROS).

These molecules act on multiple cell targets associated with drug resistance, including

the bacterial cell wall, nucleic acids, and proteins. A careful use of this strategy is

necessary since ROS attack healthy cells and bacteria indiscriminately.
The innovation
The need of the hour is a portable, cheap and accurate device to detect and overcome

antibiotic resistance. Paper-based platforms, including biosensors and sterilization

paper, have stolen the limelight in this regard because of multiple advantages: low cost,

sustainability, safety, and ease of adjustment. The current study focuses on a paper-

based bandage device to detect and

treat infection selectively after sensing antibiotic resistance.
The basis of the bandage is colorimetry. And

tapes and plasters are also

needed. It contains bromyothymol B that is green at first but becomes yellow on

encountering acids that are found in the microenvironment of a bacterial infection. In

this situation, the material releases an antibiotic, ampicillin, loaded on nanoparticles

and coated with the sugar chitosan that attracts bacteria due to their negative charge.

When the nanoparticles come into contact with the acid environment, they release the

drug. If the bacteria are sensitive to this drug, they will be killed. If otherwise, they

secrete beta-lactamase to inactivate the drug. This enzyme acts on the yellow molecule

nitrocefin to turn it red.
If the bandage for

first aid becomes red, the researchers will pass light through the bandage, which

stimulates the production of reactive oxygen species from a metallo-organic compound

called PCN-224, built on a porphyrin base, and which has high photodynamic properties,

releasing a flood of ROS in response to light. These inhibit or weaken the bacteria,

increasing their susceptibility to the drug. Thus, the

tubular bandage has

been proved to accelerate wound healing in mice after introducing both drug-sensitive and

drug-resistant bacteria into the wounds.
HOW TO CARE FOR RAW OPEN SKIN WOUNDS?
All raw wounds will heal if there is enough blood supply to the area, and if the raw

tissues are not allowed to “dry and die.” Open raw wounds will heal with proper care

even if there is exposed fat, bone, tendon, muscle, or joint. Red is raw; pink is healed.

If the wound is red, it has lost the waterproof barrier of skin and it is an open or raw

wound that oozes liquid as our bodies are 80% water. The most important part of the care

of raw wounds is to keep them clean and greasy so the tissues do not dry and die. Wounds

all over the body can be treated in this manner. Below, we illustrate 4 typical case

examples where we use this approach in complex wounds of the foot, hand, fingertips,2 and

face with exposed bone, cartilage, joints, and tendons. In some cases, if there are deep,

open, caved in wounds, we add a vacuum assisted wound dressing to accelerate flattening the cave.
What Kind of Operation

Bandage Do We Need for Wounds?
Dressings do not need to be sterile, just clean.6 Sterile dressings are expensive and

unnecessary. Coban tape off the roll is a good clean dressing that can be directly

applied over grease on fingers and leg wounds.2 Panty liners, sanitary napkins, and

diapers out of the package are another good source of clean inexpensive dressings.7 Every

day, the old dressing is removed and the patient gets in the shower to let clean water

run over the wound. After the shower, grease is applied thickly to a clean bandage. That

is placed on the wound to pad it, protect it, and keep it moist until tomorrow