Lipid-Bilayer Dynamics Probed by a Carbon Dot-Phospholipid Conjugate

Abstract

Elucidating the dynamic properties of membranes is important for understanding fundamental cellular processes and for shedding light on the interactions of proteins, drugs, and viruses with the cell surface. Dynamic studies of lipid bilayers have been constrained, however, by the relatively small number of pertinent molecular probes and the limited physicochemical properties of the probes. We show that a lipid conjugate comprised of a fluorescent carbon dot (C-dot) covalently attached to a phospholipid constitutes a versatile and effective vehicle for studying bilayer dynamics. The C-dot-modified phospholipids readily incorporated within biomimetic membranes, including solid-supported bilayers and small and giant vesicles, and inserted into actual cellular membranes. We employed the C-dot-phospholipid probe to elucidate the effects of polymyxin-B (a cytolytic peptide), valproic acid (a lipophilic drug), and amyloid-β (a peptide associated with Alzheimer's disease) upon bilayer fluidity and lipid dynamics through the application of various biophysical techniques.

Bifunctional Carbon‐Dot‐WS2 Nanorods for Photothermal Therapy and Cell Imaging

“…The fluorescence properties of C‐dots are known to exhibit sensitivity to the molecular environments of the particles . In particular, shifts in the emission peaks have been reported following covalent coupling of C‐dots to other substances . Indeed, the experimentally significant shift of the emission peak depicted in Figure D, from around 450 nm in the case of soluble C‐dots prepared from the gemini glucose‐derivative surfactant to approximately 430 nm for the WS 2 ‐C‐dot system, is indicative of covalent conjugation of the C‐dots and WS 2 nanoparticles.…”

“…[16,18] In particular, shifts in the emission peaks have been reported following covalent coupling of C-dotst oo ther substances. [18,19] Indeed, the experimentally significant shift of the emission peak depicted in Figure 2D,f rom around4 50 nm in the case of soluble Cdots preparedf rom the geminig lucose-derivative surfactantt o approximately 430 nm for the WS 2 -C-dot system, is indicative of covalent conjugation of the C-dots and WS 2 nanoparticles. Examination of other excitation-dependent emission peaks revealed similar shifts between soluble C-dots and WS 2 -attached C-dots ( Figure S4, SI).…”

“…The fluorescence emission spectra (excitation at 375 nm) of C‐dots in solution and WS 2 ‐attached C‐dots in Figure D further corroborated the microscopy data and attested to chemical coupling between the C‐dots and the WS 2 NRs. The fluorescence properties of C‐dots are known to exhibit sensitivity to the molecular environments of the particles . In particular, shifts in the emission peaks have been reported following covalent coupling of C‐dots to other substances .…”

Organic dots (O-dots) for theranostic applications: preparation and surface engineering

“…199 Jelinek and colleagues made signicant contributions to elucidate the interaction of CQDs with lipids/ membranes. [200][201][202] In one study, they showed that amphiphilic CQDs could insert into the lipid bilayer of giant vesicles and induce FRET energy transfer from the CQDs to dyes embedded in the membrane. 203 By conjugating the amphiphilic CQDs with phospholipids, the same group developed a new probe for the study of the environment and processes occurring in membranes.…”

Study Carbon Quantum Dots in Micellar Media

“…Since then, the simplicity of synthesis and unique properties of CQDs has attracted lots of interest which are reflected in publications relating their synthetic methodologies optical properties and various applications [2][3][4][5][6][7][8][9][10]. Carbon quantum dots (CQDs) have inspired extensive studies on them due to their great potential in the biological field and ability to interact with surfactants [11] model lipid bilayers [12], and biomembranes [13].…”