The physico-chemical and biological analysis of microbial biosurfactants (BSs) for applications towards cancer therapies, wound healing dressings and drug delivery

Microbial biosurfactants (BSs) are secondary metabolites with a broad-spectrum of therapeutic applications including possible cancer therapy, chronic wound healing and nanoparticulate drug delivery systems. However, due to their individual complexities, there is limited physico-chemical analysis relevant to their drug delivery applications. The aims of this research are the systematic investigation of free BSs in cancer therapy as well as the formulation of free BSs and niosomes encapsulating BSs incorporated into lyophilised composite polymeric wound dressings for potential chronic wound healings. The physico-chemical characteristics of four selected BSs 95Dd rhamnolipids (BS1a), 95/90 rhamnolipids (BS1b), surfactin (BS2) and 1′, 4″-sophorolactone 6′, 6″-diacetate (BS3) were investigated through LC-MS, ATR-FTIR and surface tension analysis. This was followed by examination of cytotoxic activities determined via MTT assay following cell line-specific optimisation at intervals of 24, 48 and 72 h treatment on non-cancerous human embryo kidney (HEK 293), human Caucasian breast adenocarcinoma (MCF-7) and human leukaemia monocyte (THP-1) cell lines. The BSs were subsequently formulated in the form of niosomes initially in deionised water, which was followed by formulation of R-90 rhamnolipids (BS1c), REWOFERM SL ONE (BS4a), REWOFERM SL 446 (BS4b) and BS2 in PBS buffer and characterised for size, size distribution, zeta potential, ATR-FTIR, XRD and SEM in transmission mode. Once optimised, free BSs and BSs based niosomes were loaded into composite lyophilised wafer dressings comprising k-carrageenan (CARR) and sodium alginate (SA) as bioactive (medicated) wound dressings to potentially target the inflammatory phase of wound healing. Both wafer formulations were functionally characterised for hardness, ATR-FTIR, XRD, mucoadhesion and exudate handling properties. Anticancer activity was successfully detected and compared in all BSs selected for investigation in cancerous cells, additionally, all BSs had higher selectivity index than doxorubicin (DOX) and therefore have potential application as an anticancer agents. Novel, durable, porous, composite advanced wound dressings incorporating free BSs and niosome encapsulated BSs were developed for potential delivery of microbial BSs in chronic wounds.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Greenwich

Year dc:date.issued

2017

Author dc:creator

• Akiyode, Olufunke Ajoke

Advisors dc:contributor.advisor

• Boateng, Joshua
• Getti, Giulia
• George, Daliya

• QD Chemistry

Language dc:language

en