Amino acid-immobilized copper ion-modified carbon-based adsorbent for selective adsorption of bovine hemoglobin

We prepared an amino acid-immobilized copper ion-modified carbon-based adsorbent (C@TA@P@A-Cu) for selective bovine hemoglobin (BHb) adsorption in biological samples. Carbon nanoparticles were used as the matrix, and copper ions were attached to the amino acid-modified carbon nanoparticles as metal chelate complexes via immobilized metal affinity. BSA, Lyz, OVA, and HRP were chosen as reference proteins for further study. Furthermore, the synthesis conditions of adsorbents, SPE conditions, selectivity, competitivity, reproducibility, and reusability were extensively investigated. The results showed that the maximum adsorption capacity of C@TA@P@A-Cu microspheres for BHb under optimal conditions was 673.0 mg g^-1. The addition of a TiO₂ layer with an increased specific surface area of the adsorbent and the addition of poly-l-lysine (PLL) inhibited the adsorbent's binding ability to non-BHb proteins, but chelated Cu²⁺ increased the adsorbent's specific binding ability to BHb. Furthermore, after six adsorption-desorption cycles, the adsorbent has satisfactory reusability with no significant change in adsorption capacity. Furthermore, C@TA@P@A-Cu was successfully used to identify BHb from real blood samples, as confirmed by SDS-PAGE, and it is expected to have potential applications in protein purification and disease diagnosis.

Theranostic platforms for specific discrimination and selective killing of bacteria

Bacterial infections are serious threats to public health due to lack of advanced techniques to rapidly and accurately diagnose these infections in clinics. Although bacterial infections can be treated with broad-spectrum antibiotics based on empirical judgment, the emergence of antimicrobial resistance has attracted global attention due to long-term misuse and abuse of antibiotics by humans in recent decades. Therefore, it is imperative to selectively discriminate and precisely eliminate pathogenic bacteria. Herein, in addition to the conventional methods for bacterial identification, we comprehensively reviewed the recently developed theranostic platforms for specific discrimination and selective killing of bacteria according to their different interactions with the target bacteria, such as electrostatic and hydrophobic interactions, molecular recognition, microenvironment response, metabolic labeling, bacteriophage targeting, and others. These theranostic agents not only benefit from improved therapeutic efficiency but also present limited susceptibility to induce bacterial resistance. The strategies summarized in this review will open up new avenues in developing effective antimicrobial materials to accurately diagnose and treat bacterial infections in the post-antibiotic era. STATEMENT OF SIGNIFICANCE: Bacterial infections are difficult to be rapidly and accurately diagnosed, and are generally treated with broad-spectrum antibiotics, which leads to the development of drug resistance. By integrating imaging modalities and therapeutic methods in a single treatment, various theranostic agents have been developed to address the abovementioned issues. Therefore, the emerging theranostic platforms for selective identification and elimination of bacteria based on the distinct interactions of the theranostic agents with the target bacteria are summarized in this review. We believe that the information provided in this review will guide researchers in designing advanced antibacterial theranostics for practical applications in the post-antibiotic era.