Insights into the interaction of human serum albumin and carbon dots: Hydrothermal synthesis and biophysical study

https://doi.org/10.1016/j.ijbiomac.2020.01.238Get rights and content

Highlights

  • The three different N,S-CDs were synthesized by various carbon source.

  • The discrepancy property of three N,S-CDs was system discussed.

  • The interaction mechanism between N,S-CDs and HSA was illuminated by multiple method.

  • The molecular docking had been successfully applied to study the N,S-CDs interaction with HSA.

  • The interaction mechanism between N,S-CDs and HSA were presented.

Abstract

Nitrogen and sulfur co-doped carbon dots (N,S-CDs) have been widely studied with high quantum yield (QY). The experimental conditions of three different N,S-CDs were optimized. Emission peak position of three different N,S-CDs shown almost remains unchanged or obvious excitation-dependent PL properties, that was likely owed to size distribution. In order to discuss the N,S-CDs stability of photoluminescence property in environment, various experiments such as the photostability, different pH, ionic strengths and temperature were designed. To sum up, three different N,S-CDs exhibited discrepancy property. Molecular interaction of three different N,S-CDs were produced via vary carbon source with human serum albumins have been investigate by various methods. The quenching mechanism, thermodynamic and kinetic parameters, binding sites, electrochemical behavior of three different N,S-CDs with human serum albumins have some different, but conformational change of three different N,S-CDs with human serum albumins alike. The molecular docking had successful applied to study the N,S-CDs interaction with HSA. Different N,S-CDs possessed various characteristic that will have different quenching mechanism when they interaction with human serum albumin, study the mechanism of action at molecular level will help people to choose suitable CDs to apply in nanomedical.

Introduction

Among carbon-base nanomaterials carbon dots (CDs) have attracted considerable attention. Compared with polymers, conventional organic dyes, metal nanoparticles and semiconductor quantum dots, CDs possess numerous superior property such as low toxicity, good biocompatibility, environment-friendly, ease of functionalization, highly water-dispersible, easy preparation as well as photostability [[1], [2], [3], [4]]. Thus, CDs have presented great potential in various applications, including biomedicine, bioimaging, biosensing, optoelectronic devices, fluorescent probes, et al. [2,[5], [6], [7], [8]]. However, there are some urgent questions to solve. For instance, most of CDs have a relatively low quantum yield, a short-wavelength blue-green region of CDs distinctly confine CDs application in biologically-relevant fields. Different method including heteroatom doping, surface functional and surface passivation were used to improve the property of CDs. Heteroatom doping include nitrogen, sulfur, fluorine, phosphorus and boron, etc. It through improving optical and electronic properties, improving affinity and increasing the quantum yield of CDs. Nitrogen (N) atom can combine strongly with the C atom due to the size of it being similar to C; S doping can tune the maximum fluorescence emission of CDs to a longer wavelength, and improve the fluorescence intensity of CDs. So, nitrogen and sulfur heteroatom doping are used to prepare CDs in this study [[9], [10], [11], [12], [13]].

Serum albumins are the most plentiful protein of blood plasma, that consists of three homologous domains, each domain is divided into two subdomains. Human serum albumins (HSA) are used widely as a biological model to study the molecular interaction with nanoparticle, which can carriage, allocation, and pass on many endogenous and exogenous substances [[14], [15], [16]]. To date, CDs is appeal to tremendous biomedical applications, an increasing number of researchers to probe the molecular interaction in between biomacromolecule and CDs [7,15]. Drug interaction with proteins can be modulated the bioavailability of drug, variation of binding constants of three drugs with HSA and γ-globulins with different concentration of CDs were discussed [17]. The quenching constants, thermodynamic parameters, binding location and conformation changes between CDs with different serum albumins were explored [18,19]. CDs as a fluorescent probe to selective bovine serum albumin and DNA were investigated [20,21]. Not only different optical properties, discrepancy particle sizes but also surface chemical properties of obtained CDs by discrepancy synthetic methods and raw materials, thus, there are different effect on protein structure and function via interaction with each kind of CDs [22].

In this research, three different N,S-CDs were produced via vary carbon source, interaction with human serum albumin have been discussed. To our knowledge, system compare the influence of different carbon source to synthesis N,S-CDs and compare different N,S-CDs interaction with human serum albumin is rarely to report. The molecular docking had successful applied to study the N,S-CDs interaction with HSA. Discrepancy quantum yield and property of N,S-CDs were produced. Different N,S-CDs possessed various characteristic that will have different quenching mechanism when they interaction with human serum albumin, study the mechanism of action at molecular level will help people to choose suitable CDs to apply in nanomedical.

Section snippets

Materials

Ascorbic acid (AA) and N-Acetyl-L-cysteine (NAC) were purchase from Sinopharm Chemical Reagent. HSA and hydroxymethyl aminomethanne (Tris) were purchase from Sigma-Aldrich (St. Louis, MO, USA); ibuprofen and warfarin were purchase from Hubei Biocause Pharmaceutical Co., Ltd. (Hubei, China; the purity no less than 99.7%) and Trust Chemical Industry Co., Ltd. (Nanjing, China; the purity no less than 99.5%), respectively; Every other reagents used everywhere this research were analytical purity.

Characterization of CDs

The different reaction times and the various doping agents can affect the QY of N,S-CDs. The QY of CDs (CA) reaction time for 1 h, 1.5 h, 2 h, 2.5 h and 3 h was had be discussed. As illustrated in Fig. 2S(A), the QY were 38.70%, 68.50%, 51.70%, 37.20% and 35.90% for the reaction time 1 h, 1.5 h, 2 h, 2.5 h and 3 h of CDs (CA), respectively. As shown in Fig. 2S(B), the QY of CA add with urea or CA add with NAC are 17.00% and 43.30%, respectively. The experimental conditions were optimized as

Conclusions

In this study, high QY of N,S-CDs was prepared via using citric acid as carbon source, and other two different N,S-CDs were produced via vary carbon source. The discrepancy between three different N,S-CDs were discussed, for example, particle diameters, lattice parameters, distinction emission wavelength, et al. When three different N,S-CDs interaction with HSA respectively shown different quenching mechanism, the quenching mechanism between CDs (AA) with HSA is static quenching, the quenching

CRediT authorship contribution statement

Chun-Yan Liang: Data curation, Formal analysis, Investigation, Methodology, Software, Validation, Visualization, Writing-original draft. Juan Pan: Data curation, Formal analysis, Investigation, Software, Validation. Ai-Min Bai: Resources, Supervision. Yan-Jun Hu: Conceptualization, Funding acquisition, Project administration, Resources, Supervision, Writing-review & editing.

Declaration of competing interest

There are no conflicts to declare.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 21273065), and the Science and Technology Foundation for Excellent Creative Research Group of Hubei Provincial Department of Education (T201810).

References (44)

  • L.B. Li et al.

    Nitrogen and sulfur co-doped carbon dots for highly selective and sensitive detection of Hg (II) ions

    Biosens. Bioelectron.

    (2015)
  • C.X. Wang et al.

    A hydrothermal route to water-stable luminescent carbon dots as nanosensors for pH and temperature

    Carbon

    (2015)
  • F. Gao et al.

    Rational design of high quality citric acid-derived carbon dots by selecting efficient chemical structure motifs

    Carbon

    (2017)
  • T. Chatzimitakos et al.

    Human fingernails as an intriguing precursor for the synthesis of nitrogen and sulfur-doped carbon dots with strong fluorescent properties: analytical and bioimaging application

    Sens. Actuators B: Chem.

    (2018)
  • R.X. Wang et al.

    One-step synthesis of self-doped carbon dots with highly photoluminescence as multifunctional biosensors for detection of iron ions and pH

    Sens. Actuators B: Chem.

    (2017)
  • J.X. Duan et al.

    A rapid microwave synthesis of nitrogen–sulfur co-doped carbon nanodots a shighly sensitive and selective fluorescence probes for ascorbic acid

    Talanta

    (2016)
  • J.C. Chen et al.

    One-pot synthesis of nitrogen and sulfur co-doped carbon dots and its application for sensor and multicolor cellular imaging

    J. Colloid Interf. Sci.

    (2017)
  • Y.F. Chen et al.

    Facile synthesis of nitrogen and sulfur co-doped carbon dots and application for Fe(III) ions detection and cell imaging

    Sens. Actuators B: Chem.

    (2016)
  • Y.J. Hu et al.

    Fluorometric investigation of the interaction of bovine serum albumin with surfactants and 6-mercaptopurine

    J. Photochem. Photobiol. B-Biol.

    (2005)
  • M. Ishtikhar et al.

    Interaction of 5-fluoro-5′-deoxyuridine with human serum albumin under physiological and non-physiological condition: a biophysical investigation

    Colloids and Surface B

    (2014)
  • G. Rabbani et al.

    Binding of erucic acid with human serum albumin using a spectroscopic and molecular docking study

    Int. J. Biol. Macromol.

    (2017)
  • X.Y. Xie et al.

    Binding of the endocrine disruptors 4-tert-octylphenol and 4-nonylphenol to human serum albumin

    J. Hazard. Mater.

    (2013)
  • Cited by (16)

    • Investigation on conformational variation and fibrillation of human serum albumin affected by molybdenum disulfide quantum dots

      2021, International Journal of Biological Macromolecules
      Citation Excerpt :

      Liu's group revealed the effect of CdTe QDs on the conformation and the esterase activity of HSA [16]. Many scientific researchers used various analytical methods and technologies to deeply study the binding mechanisms of iron oxide nanoparticles [17] and carbon dots [18] with HSA. All these results indicated that nanoparticles can combine with HSA and further cause the changes in the conformation of HSA, finally causing irreversible influences on the biological functions of HSA.

    View all citing articles on Scopus
    View full text