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Naphthalimide-based multifunctional AIEgens: Selective, fast, and wash-free fluorescence tracking and identification
Sayed Mir Sayed1, Ke-Fei Xu1, Hao-Ran Jia1
1State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, 2 Sipailou Road, Nanjing, 210096, PR China.
Abstract:
Pathogenic infections, particularly caused by Gram-positive bacteria (G+), pose a serious threat to human health, and therefore the fast and accurate discrimination of G+ bacteria from Gram-negative bacteria (G-) and fungi is highly desirable. Organic molecules with facile synthesis, robust photostability, good biocompatibility, and high selectivity toward pathogens are urgently needed in the clinical diagnosis and therapy. To this end, herein we report the synthesis of two naphthalimide-based bioprobes named tetraphenylethylene-naphthalimide (TPE-NIM) and triphenylamine-naphthalimide (TPA-NIM) with aggregation-induced emission (AIE) characteristic. First, the staining capacity of the designed AIEgens toward six kinds of bacteria and two kinds of fungi was evaluated. Both TPE-NIM and TPA-NIM showed a high degree of binding/imaging selectivity for G+ bacteria over G- bacteria and fungi via a wash-free protocol. Second, the two AIEgens had the ability to visualize the biofilms formed by G+ bacteria (Staphylococcus aureus) and can quickly track the G+ bacteria (Staphylococcus aureus) in red blood cell suspensions. Third, we have revealed that electrostatic attraction and hydrophobic interaction both contribute to the selective binding of the AIEgens toward G+ bacteria. In view of the high binding/imaging specificity toward G+ bacteria, low hemolysis rates, and low toxicity toward the bacterial cells, these AIEgens can be applied for the clinical detection of pathogenic infections caused by G+ bacteria and broaden the theranostic applications of AIE materials.
Insights
New organic molecules selectively detect Gram-positive bacteria, offering a fast and accurate diagnostic tool for infections. These probes also visualize bacterial biofilms and track pathogens in blood, improving clinical detection and theranostic applications.
Area of Science:
- Biochemistry
- Organic Chemistry
- Medical Diagnostics
Background:
- Pathogenic infections, especially Gram-positive bacterial infections, represent a significant global health concern.
- Rapid and precise differentiation of Gram-positive bacteria from Gram-negative bacteria and fungi is crucial for effective clinical management.
- There is a pressing need for novel organic molecules that are easily synthesized, photostable, biocompatible, and highly selective for pathogens.
Purpose of the Study:
- To synthesize and characterize novel naphthalimide-based bioprobes with aggregation-induced emission (AIE) properties.
- To evaluate the selectivity and efficacy of these AIE probes in detecting Gram-positive bacteria, their biofilms, and tracking them in biological samples.
- To elucidate the interaction mechanisms responsible for the selective binding of the AIE probes to Gram-positive bacteria.
Main Methods:
- Synthesis of two AIEgens: tetraphenylethylene-naphthalimide (TPE-NIM) and triphenylamine-naphthalimide (TPA-NIM).
- Evaluation of staining capacity and selectivity against six bacterial and two fungal species using a wash-free protocol.
- Visualization of Staphylococcus aureus biofilms and tracking of S. aureus in red blood cell suspensions.
- Investigation of binding mechanisms through analysis of electrostatic attraction and hydrophobic interactions.
Main Results:
- Both TPE-NIM and TPA-NIM demonstrated high selectivity for Gram-positive bacteria over Gram-negative bacteria and fungi.
- The AIEgens successfully visualized Gram-positive bacterial biofilms and tracked Staphylococcus aureus in blood.
- Electrostatic attraction and hydrophobic interactions were identified as key factors in the selective binding to Gram-positive bacteria.
- The probes exhibited low hemolysis rates and low toxicity to bacterial cells.
Conclusions:
- The developed naphthalimide-based AIEgens offer a promising platform for the selective detection and imaging of Gram-positive bacterial infections.
- These bioprobes show potential for clinical diagnostics, biofilm visualization, and theranostic applications in infectious diseases.
- The findings contribute to the advancement of AIE materials for biomedical imaging and pathogen detection.
