Conjugation of Carboxylated Graphene Quantum Dots with Cecropin P1 for Bacterial Biosensing Applications

Abstract

Biosensors that can accurately and rapidly detect bacterial concentrations in solution are important for potential applications such as assessing drinking water safety. Meanwhile, quantum dots have proven to be strong candidates for biosensing applications in recent years because of their strong light emission properties and their ability to be modified with a variety of functional groups for the detection of different analytes. Here, we investigate the use of conjugated carboxylated graphene quantum dots (CGQDs) for the detection of Escherichia coli using a biosensing assay that focuses on measuring changes in fluorescence intensity. We have further developed this assay into a novel, compact, field-deployable biosensor focused on rapidly measuring changes in absorbance to determine E. coli concentrations. Our CGQDs were conjugated with cecropin P1, a naturally produced antibacterial peptide that facilitates the attachment of CGQDs to E. coli cells; to our knowledge, this is the first instance of cecropin P1 being used as a biorecognition element for quantum dot biosensors. As such, we confirm the structural modification of these conjugated CGQDs in addition to analyzing their optical characteristics. Our findings have the potential to be used in situations where rapid, reliable detection of bacteria in liquids, such as drinking water, is required, especially given the low range of E. coli concentrations (10 3 to 10 6 CFU/mL) within which our two biosensing assays have collectively been shown to function.

Evolution of Photoluminescent CdS Magic-Size Clusters Assisted by Adding Small Molecules with Carboxylic Group

“…With the addition of HOAc, MSC-373 formed, which should be more stable, and will not transform to QDs. We believe that the present study will open up a new avenue to prepare a series of MSCs with photoluminescent property for various applications. ,,, Also, the current study may inspire efforts to narrow the knowledge gap regarding the structure–property relationship of CdS MSCs and their possible transformations. ,,,, …”

Nanomaterials in the Management of Gram-Negative Bacterial Infections

“…Labeled gold NPs A perfect Detect of E. coli 500 CFU mL −1 in 1 mL of sample [75] DNA-gold NPs Detection of bacteria with low concentration of 2 × 10 3 CFU mL −1 [76] Protein-gold NPs No cross-reactivity for Gram-negative pathogens [77] gold@MoS 2 -PANI nanocomposite 10 CFU mL −1 for LOD in just 30 min [78] Peptide-gold NPs LOD and LOQ for E. coli measurement was 2 and 6 CFU mL −1 , respectively [79] Protein-gold NPs A perfect LOD of 4 × 10 3 CFU mL −1 , reusable potential, and wide-range analysis of 2 × 10 4 -2 × 10 7 CFU mL −1 for E. coli detection [80] Ag NPs Ag-gold alloy nanohole arrays Label-free detection, wide-range analysis of 10 3 -10 8 CFU mL −1 and LOD of 59 CFU mL −1 [81] Polymer-Ag NPs Wide range analysis of 0.001-100 ng mL −1 and 10-10 7 CFU mL −1 [82] QDs Mannose-ZnTe QDs Good selectivity and a perfect linearity range of 1.0 × 10 5 -1.0 × 10 8 CFU mL −1 toward E. coli [83] CdS QDs@MOF Suitable linear range of 10-10 8 CFU mL −1 , LOD of 3 CFU mL −1 and S/N of 3 [84] carboxylated graphene QD Detection of pathogen in drinking water in low concentrations of E. coli (10 3 -10 6 CFU mL −1 ) [85] Carbon nanomaterials [98]. In this light, Li et al developed a procedure for detecting the E. coli O157:H7 bacteria by using gold NP labelling, antibody affinity binding, and inductively coupled plasma mass spectrometry (ICPMS) [75].…”

“…Bruce et al used a biosensing test that emphasized monitoring changes in fluorescence intensity to examine the application of conjugated carboxylated graphene CGQDs to identify E. coli [85]. Cecropin P1, a naturally occurring antibacterial peptide that aids in the adhesion of CGQDs to E. coli cells, was conjugated to CGQDs.…”

Dual-Mode Virus Detection: Combining Electrochemical and Fluorescence Modalities for Enhanced Sensitivity and Reliability

“…29 Antibodies primarily attach to the GQD part of N,S-GQD through carboxylic groups. 30,31 CdSeS serves as the fluorescent probe, doped with sulfur to enhance its fluorescence property. 32,33 CdSeS was also functionalized with specific antibodies which bind to NoV-LP.…”