Magnetic nanoparticles detect amoxicillin allergy with 98% sensitivity in early tests

A multidisciplinary scientific team at the University of Malaga has developed a new technology based on magnetic nanoparticles that enables precise, rapid and reliable diagnosis of allergy to beta-lactam antibiotics, including amoxicillin and other penicillins.

This is a “highly efficient” in vitro diagnostic platform based on 30 nm nanoparticles with an iron oxide core and silica shell, which act “like a tiny magnet covered with thousands of molecular hooks.” “If the patient’s blood contains the IgE antibodies responsible for the allergy, they are captured much more readily than with conventional methods,” explains Ezequiel Pérez-Inestrosa, professor of organic chemistry at the University of Malaga and one of the study’s authors.

The journal Materials Today Bio reported the findings of the study, which also involved researchers from the IBIMA BIONAD Platform, the Inflammatory Diseases Network (REI) and the Regional University Hospital of Malaga. Yolanda Vida and María I. Montañez, researchers in the University of Malaga’s Department of Organic Chemistry, are the study’s lead authors.

Eliminating incorrect diagnoses

“In the tests performed, the system was able to detect virtually all true cases of allergy and reduced both false negatives and false positives,” says María José Torres, professor of medicine and another researcher leading the study.

In this regard, Torres notes that penicillin allergy is overdiagnosed. “Although between 8% and 25% of the population report being allergic to these antibiotics, only between 1% and 10% actually are. This incorrect label leads to the use of alternative drugs that are generally less effective, more toxic and contribute to the emergence of bacterial resistance,” Pérez-Inestrosa explains. He stresses the importance of identifying these cases safely, as this would make it possible to remove thousands of incorrect diagnoses that affect patients’ treatment.

Avoiding risks, simplifying the process

In addition, this new method avoids drug provocation tests with the medication itself, which carry risks for patients, because the analysis can be performed much more simply and rapidly in the laboratory, without lengthy centrifugation procedures.

For this study, blood samples from nearly 100 people were analyzed—50 patients with confirmed amoxicillin allergy and 44 individuals who tolerated these antibiotics. The new technology was also compared with two techniques: ImmunoCAP, the most widely used commercial test, and conventional RAST. Specifically for amoxicillin, the platform achieved 98% sensitivity, whereas ImmunoCAP detected only around 17%.

In light of this finding, the authors emphasize the need for further, larger multicenter studies and clinical validation before the technology can be introduced into hospitals and used routinely.

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