The new colorimetric Band-Aid: a bacterial infection like!

In recent years, the overuse of antibiotics led to the emergence and development of resistant strains has been one of the most serious threats to human health faced. Currently, there are 700,000 deaths each year and antimicrobial resistance, and therefore very important to early detect drug-resistant bacterial infections and choice of treatment options. However, the commonly used method for detecting infection is limited demand for professionals as well as expensive equipment. World Health Organization (WHO) Inspired portable and low-cost devices that sustainable paper equipment (PBD), the bio-safety, low cost and easy to make the properties is expected to be a promising antimicrobial therapy platform. In recent years, PBD has been widely used in portable biosensor paper and sterilization. However, it is reported to achieve sensing and therapeutic functions of bacteria by PBD has not yet appeared.

Highlights

Recently, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Qu Xiaogang, a researcher developed for sensing and for portable therapy resistant paper base adhesive bandage (PBA) . The adhesive bandage as bacterial resistance to the same color chart is determined by the presence or absence of a color change resistant bacteria, and selective antibacterial embodiment Policy . Researchers successfully detected by the PBA and effective in treating E. coli (E. coli) in drug-sensitive (DS) and resistant (DR) strains. The design can maximize the therapeutic effects and real-time tracking with the naked eye to detect drug-resistant, and low production cost and easy to operate, has opened up a new way to detect and treat bacterial infections.

Preparation of the PBA design and

Researchers porphyrins first synthesized MOF-based nanoparticles PCN-224 at 90 ° C; then on the surface of the PCN-224 chitosan (CS) attached to the to obtain PCN-224 @ CS (CP) in order to achieve an acid response characteristic. Figure SEM and TEM 1 CS display of the modification does not affect the integrity of the MOF structure. Subsequently, 1C, fixing the CP obtained portable Paper @ CP in sterile cellulose paper, cellulose paper hydroxyl group to an aldehyde group by periodate oxidation; followed by formation of a secondary amine of the CP uniform distributed on the paper, so that has been successfully modified cellulose paper CP PBA .

PBA sensed bacterial infection

Researchers coli and the mixture was incubated CP and the BTB, the results 2B, with the increase of the concentration of bacteria, E. coli DS or DR added, and the PBA will turn yellow, indicating that the ability to have an acid responsiveness. The E. coli solution was then dripped onto the paper PBA, 2C, in the presence of DR E. coli, PBA changes from green to red, and the higher concentration of bacteria, PBA darker red, in line with the clinical diagnosis of need. This may indicate that the by a sense of color change PBA measured bacterial infection and prompt bacterial resistance. Applications

in the selective treatment of the PBA

Subsequently , researchers conducted selective antibacterial experiment shown in FIG. 3. The amount of the PBA four CP preparation for DS E. coli, which increases the survival rate and decreased the amount of CP; CP concentration varies no significant effect on survival DR E. coli, but after the light irradiation survival ability becomes extremely low. This suggests that the chemotherapy alone can treat DS E. coli infection, DR E. coli is required chemotherapy and photodynamic therapy in combination. It also shows that the PBA is a promising method for the selective antibacterial.

Validity of the detector

Validity of the equipment is an important indicator in practical applications, research PBA will be placed 4 ° C for sealed, then removed and antibacterial sensing experimental results shown in FIG., one month after the PBA still DS and DR E. coli showed a color change corresponding to 4, and maintained of E. coli effective sterilization capability. Thus, PBA is valid for at least one month.

PBA wounds disinfected mice

Researchers PBA for sensing and treating injured mice. 5A, and DS respectively wound DR E. coli infection, and adhere to the wound PBA. For DS E. coli infection, all showed a yellow paper, wound almost completely healed on the third day; for DR E. coli infection, PBA are red, and when the PBA and photodynamic therapy combination therapy, wound healing more it is good. This indicates that the PBA may effectively E. coli infection is sensed, thereby contributing to the choice of treatment.

Potential applications of the PBA

Finally, the researchers constructed as shown in FIG. 6 infected tomato models and PBA attached to the site of infection, in order to further demonstrate the therapeutic potential of sense and the PBA. Strains in a mixed group, the next day the PBA appear red, if not any light treatment, 3 days after infection site tomatoes will become soft and recessed, and the surface appeared thousands of bacteria. further confirmed the PBA has the ability to perceive and real-time monitoring of bacterial infections resistant bacteria. Tomato picture during

In this article, the researchers constructed an visualizing the PBA portable, can sense resistant and selective antibacterial strategies embodiment, compared with conventional antimicrobial strategies, the PBA possible to visually tracking real resistant, to reduce the side effects of off-target effects, meet the needs of clinical diagnosis. We believe that this technology is expected to provide a new method for the detection and treatment of bacterial infections, will greatly promote the development of next-generation medical applications! Original link: https: //pubs.acs.org/doi/10.1021/acscentsci.9b01104