High throughput microencapsulation of Bacillus subtilis in semi-permeable biodegradable polymersomes for selenium remediation
- 718 Downloads
Encapsulating bacteria within constrained microenvironments can promote the manifestation of specialized behaviors. Using double-emulsion droplet-generating microfluidic synthesis, live Bacillus subtilis bacteria were encapsulated in a semi-permeable membrane composed of poly(ethylene glycol)-b-poly(d,l-lactic acid) (mPEG-PDLLA). This polymer membrane was sufficiently permeable to permit exponential bacterial growth, metabolite-induced gene expression, and rapid biofilm growth. The biodegradable microparticles retained structural integrity for several days and could be successfully degraded with time or sustained bacterial activity. Microencapsulated B. subtilis successfully captured and contained sodium selenite added outside the polymersomes, converting the selenite into elemental selenium nanoparticles that were selectively retained inside the polymer membrane. This remediation of selenium using polymersomes has high potential for reducing the toxicity of environmental selenium contamination, as well as allowing selenium to be harvested from areas not amenable to conventional waste or water treatment.
KeywordsMicroparticles Microfluidics Double-emulsion Bacteria Biofilm Selenite Nanoparticles
Special thanks to Alireza Abbaspourrad and David A. Weitz for the demonstration of double-emulsion microfluidic device assembly techniques.
Compliance with ethical standards
This work was supported in part by the National Science Foundation (NSF) DGE-0965843, Department of Defense (DOD) W81XWH-09-2-0001, National Cancer Institute (NCI) 1R25CA174650-01A, a startup grant from Northeastern University, and the Electronics Materials Research Institute at Northeastern University. Undergraduates J.B., K.G., and C.K. were supported by the Northeastern University Provost Undergraduate Research Award, Honors Early Research Grant, and Advanced Research/Creative Endeavor Award.
Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- Agency for Toxic Substances and Disease Registry (2003) Toxicological profile for selenium (Update). AtlantaGoogle Scholar
- Chudobova D, Cihalova K, Dostalova S, Ruttkay-Nedecky B, Rodrigo MAM, Tmejova K, Kopel P, Nejdl L, Kudr J, Gumulec J, Krizkova S, Kynicky J, Kizek R, Adam V (2014) Comparison of the effects of silver phosphate and selenium nanoparticles on Staphylococcus aureus growth reveals potential for selenium particles to prevent infection. FEMS Microbiol Lett 351:195–201. doi: 10.1111/1574-6968.12353 CrossRefPubMedGoogle Scholar
- DeYoung MB, MacConell L, Sarin V, Trautmann M, Herbert P (2011) Encapsulation of exenatide in poly-(d,l-lactide-Co-glycolide) microspheres produced an investigational long-acting once-weekly formulation for type 2 diabetes. Diabetes Technol Ther 13:1145–1154. doi: 10.1089/dia.2011.0050 CrossRefPubMedPubMedCentralGoogle Scholar
- Estevam EC, Witek K, Faulstich L, Nasim MJ, Latacz G, Dominguez-Alvarez E, Kiec-Kononowicz K, Demasi M, Handzlik J, Jacob C (2015) Aspects of a distinct cytotoxicity of selenium salts and organic selenides in living cells with possible implications for drug design. Molecules 20:13894–13912. doi: 10.3390/molecules200813894 CrossRefPubMedGoogle Scholar
- Fordyce F (2013) Selenium deficiency and toxicity in the environment. In: Selinus O (ed) Essentials of medical geology, 2nd edn. Springer, pp 375–416Google Scholar
- Nichols DS, Nichols PD, McMeekin TA (1995) Ecology and physiology of psychrophilic bacteria from Antarctic saline lakes and sea-ice. Sci Prog 78:311–348Google Scholar
- Oremland RS, Herbel MJ, Blum JS, Langley S, Beveridge TJ, Ajayan PM, Sutto T, Ellis AV, Curran S (2004) Structural and spectral features of selenium nanospheres produced by Se-respiring bacteria. Appl Environ Microbiol 70:52–60. doi: 10.1128/AEM.70.1.52-60.2004 CrossRefPubMedPubMedCentralGoogle Scholar
- Sambrook J, Russell D (2001) Molecular cloning: a laboratory manual, 3rd edn. Cold Spring Harbor Laboratory Press, Cold Spring HarborGoogle Scholar
- U.S. Environmental Protection Agency (1991) Integrated risk information system (IRIS): selenium and compounds. Washington, D.C.Google Scholar
- World Health Organization (1996) Trace elements in human nutrition and health. WHO, GenevaGoogle Scholar
- Yano K, Wada T, Suzuki S, Tagami K, Matsumoto T, Shiwa Y, Ishige T, Kawaguchi Y, Masuda K, Akanuma G, Nanamiya H, Niki H, Yoshikawa H, Kawamura F (2013) Multiple rRNA operons are essential for efficient cell growth and sporulation as well as outgrowth in Bacillus subtilis. Microbiology 159:2225–2236. doi: 10.1099/mic.0.067025-0 CrossRefPubMedGoogle Scholar