Cell Biochemistry and Biophysics

, Volume 76, Issue 1–2, pp 147–159 | Cite as

Identifying the Interaction of Vancomycin With Novel pH-Responsive Lipids as Antibacterial Biomaterials Via Accelerated Molecular Dynamics and Binding Free Energy Calculations

  • Shaimaa Ahmed
  • Suresh B. Vepuri
  • Mahantesh Jadhav
  • Rahul S. Kalhapure
  • Thirumala Govender
Original Paper


Nano-drug delivery systems have proven to be an efficient formulation tool to overcome the challenges with current antibiotics therapy and resistance. A series of pH-responsive lipid molecules were designed and synthesized for future liposomal formulation as a nano-drug delivery system for vancomycin at the infection site. The structures of these lipids differ from each other in respect of hydrocarbon tails: Lipid1, 2, 3 and 4 have stearic, oleic, linoleic, and linolenic acid hydrocarbon chains, respectively. The impact of variation in the hydrocarbon chain in the lipid structure on drug encapsulation and release profile, as well as mode of drug interaction, was investigated using molecular modeling analyses. A wide range of computational tools, including accelerated molecular dynamics, normal molecular dynamics, binding free energy calculations and principle component analysis, were applied to provide comprehensive insight into the interaction landscape between vancomycin and the designed lipid molecules. Interestingly, both MM-GBSA and MM-PBSA binding affinity calculations using normal molecular dynamics and accelerated molecular dynamics trajectories showed a very consistent trend, where the order of binding affinity towards vancomycin was lipid4 > lipid1 > lipid2 > lipid3. From both normal molecular dynamics and accelerated molecular dynamics, the interaction of lipid3 with vancomycin is demonstrated to be the weakest (∆Gbinding = −2.17 and −11.57, for normal molecular dynamics and accelerated molecular dynamics, respectively) when compared to other complexes. We believe that the degree of unsaturation of the hydrocarbon chain in the lipid molecules may impact on the overall conformational behavior, interaction mode and encapsulation (wrapping) of the lipid molecules around the vancomycin molecule. This thorough computational analysis prior to the experimental investigation is a valuable approach to guide for predicting the encapsulation ability, drug release and further development of novel liposome-based pH-responsive nano-drug delivery system with refined structural and chemical features of potential lipid molecule for formulation development.


pH-responsive lipids Liposomes Nano-drug delivery systems (NDDS) Vancomycin Molecular dynamics Binding affinity calculations 



The authors are thankful to National Research Foundation of South Africa, University of KwaZulu-Natal and UKZN Nano Platform for financial support and Carrin Martin for editing.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no competing interests.


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Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  • Shaimaa Ahmed
    • 1
  • Suresh B. Vepuri
    • 1
  • Mahantesh Jadhav
    • 1
  • Rahul S. Kalhapure
    • 1
  • Thirumala Govender
    • 1
  1. 1.Discipline of Pharmaceutical Sciences, School of Health SciencesUniversity of KwaZulu-NatalDurbanSouth Africa

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