Marine Biosilica as a Tool to Understand the Therapeutic Benefit of Silica in Bone Repair

Pamela Walsh, Susan Clarke, Matthew Julius, Fraser Buchanan, Phillip B Messersmith

Research output: Contribution to conferenceAbstract

Abstract

It is widely accepted that silicon-substituted materials enhance bone formation, yet the mechanism by which this occurs is poorly understood. This work investigates the potential of using diatom frustules to answer on fundamental questions surrounding the role of silica in bone healing. Biosilica with frustules 20m were isolated from Cyclotella meneghiniana a unicellular microalgae that was sourced from the Mississippi River, USA. Silanisation chemistry was used to modify the surface of C. meneghiniana with amine (–NH2) and thiol (–SH) terminated silanes. Untreated frustules and both functionalised groups were soaked in culture medium for 24hrs. Following the culture period, frustules were separated from the conditioned medium by centrifugation and both were tested separately in vitro for cytotoxicity using murine-monocyte macrophage (J774) cell line. Cytotoxicity was measured using LDH release to measure damage to cell membrane, MTS to measure cell viability and live-dead staining. The expression and release of pro-inflammatory cytokines (IL-6 and TNF) were measured using ELISA. Our results found that diatom frustules and those functionalised with amino groups showed no cytotoxicity or elevated cytokine release. Diatom frustules functionalised with thiol groups showed higher levels of cytotoxicity. Diatom frustules and those functionalised with amino groups were taken forward to an in vivo mouse toxicity model, whereby the immunological response, organ toxicity and route of metabolism/excretion of silica were investigated. Histological results showed no organ toxicity in any of the groups relative to control. Analysis of blood Si levels suggests that modified frustules are metabolised quicker than functionalised frustules, suggesting that physiochemical attributes influence their biodistribution. Our results show that diatom frustules are non cytotoxic and are promising materials to better understand the role of silica in bone healing.
Original languageEnglish
Publication statusAccepted - 06 Dec 2015
Event6th International Conference on Mechanics of Biomaterials and Tissues - Hawaii, Waikoloa, United States
Duration: 06 Dec 201510 Dec 2015

Conference

Conference6th International Conference on Mechanics of Biomaterials and Tissues
CountryUnited States
CityWaikoloa
Period06/12/201510/12/2015

Fingerprint

Diatoms
Silicon Dioxide
Bone and Bones
Sulfhydryl Compounds
Immunological Models
Cytokines
Microalgae
Therapeutics
Mississippi
Silanes
Silicon
Conditioned Culture Medium
Centrifugation
Rivers
Osteogenesis
Amines
Culture Media
Monocytes
Interleukin-6
Cell Survival

Cite this

Walsh, P., Clarke, S., Julius, M., Buchanan, F., & Messersmith, P. B. (Accepted/In press). Marine Biosilica as a Tool to Understand the Therapeutic Benefit of Silica in Bone Repair. Abstract from 6th International Conference on Mechanics of Biomaterials and Tissues, Waikoloa, United States.
Walsh, Pamela ; Clarke, Susan ; Julius, Matthew ; Buchanan, Fraser ; Messersmith, Phillip B . / Marine Biosilica as a Tool to Understand the Therapeutic Benefit of Silica in Bone Repair. Abstract from 6th International Conference on Mechanics of Biomaterials and Tissues, Waikoloa, United States.
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Walsh, P, Clarke, S, Julius, M, Buchanan, F & Messersmith, PB 2015, 'Marine Biosilica as a Tool to Understand the Therapeutic Benefit of Silica in Bone Repair', 6th International Conference on Mechanics of Biomaterials and Tissues, Waikoloa, United States, 06/12/2015 - 10/12/2015.

Marine Biosilica as a Tool to Understand the Therapeutic Benefit of Silica in Bone Repair. / Walsh, Pamela; Clarke, Susan; Julius, Matthew; Buchanan, Fraser; Messersmith, Phillip B .

2015. Abstract from 6th International Conference on Mechanics of Biomaterials and Tissues, Waikoloa, United States.

Research output: Contribution to conferenceAbstract

TY - CONF

T1 - Marine Biosilica as a Tool to Understand the Therapeutic Benefit of Silica in Bone Repair

AU - Walsh, Pamela

AU - Clarke, Susan

AU - Julius, Matthew

AU - Buchanan, Fraser

AU - Messersmith, Phillip B

PY - 2015/12/6

Y1 - 2015/12/6

N2 - It is widely accepted that silicon-substituted materials enhance bone formation, yet the mechanism by which this occurs is poorly understood. This work investigates the potential of using diatom frustules to answer on fundamental questions surrounding the role of silica in bone healing. Biosilica with frustules 20m were isolated from Cyclotella meneghiniana a unicellular microalgae that was sourced from the Mississippi River, USA. Silanisation chemistry was used to modify the surface of C. meneghiniana with amine (–NH2) and thiol (–SH) terminated silanes. Untreated frustules and both functionalised groups were soaked in culture medium for 24hrs. Following the culture period, frustules were separated from the conditioned medium by centrifugation and both were tested separately in vitro for cytotoxicity using murine-monocyte macrophage (J774) cell line. Cytotoxicity was measured using LDH release to measure damage to cell membrane, MTS to measure cell viability and live-dead staining. The expression and release of pro-inflammatory cytokines (IL-6 and TNF) were measured using ELISA. Our results found that diatom frustules and those functionalised with amino groups showed no cytotoxicity or elevated cytokine release. Diatom frustules functionalised with thiol groups showed higher levels of cytotoxicity. Diatom frustules and those functionalised with amino groups were taken forward to an in vivo mouse toxicity model, whereby the immunological response, organ toxicity and route of metabolism/excretion of silica were investigated. Histological results showed no organ toxicity in any of the groups relative to control. Analysis of blood Si levels suggests that modified frustules are metabolised quicker than functionalised frustules, suggesting that physiochemical attributes influence their biodistribution. Our results show that diatom frustules are non cytotoxic and are promising materials to better understand the role of silica in bone healing.

AB - It is widely accepted that silicon-substituted materials enhance bone formation, yet the mechanism by which this occurs is poorly understood. This work investigates the potential of using diatom frustules to answer on fundamental questions surrounding the role of silica in bone healing. Biosilica with frustules 20m were isolated from Cyclotella meneghiniana a unicellular microalgae that was sourced from the Mississippi River, USA. Silanisation chemistry was used to modify the surface of C. meneghiniana with amine (–NH2) and thiol (–SH) terminated silanes. Untreated frustules and both functionalised groups were soaked in culture medium for 24hrs. Following the culture period, frustules were separated from the conditioned medium by centrifugation and both were tested separately in vitro for cytotoxicity using murine-monocyte macrophage (J774) cell line. Cytotoxicity was measured using LDH release to measure damage to cell membrane, MTS to measure cell viability and live-dead staining. The expression and release of pro-inflammatory cytokines (IL-6 and TNF) were measured using ELISA. Our results found that diatom frustules and those functionalised with amino groups showed no cytotoxicity or elevated cytokine release. Diatom frustules functionalised with thiol groups showed higher levels of cytotoxicity. Diatom frustules and those functionalised with amino groups were taken forward to an in vivo mouse toxicity model, whereby the immunological response, organ toxicity and route of metabolism/excretion of silica were investigated. Histological results showed no organ toxicity in any of the groups relative to control. Analysis of blood Si levels suggests that modified frustules are metabolised quicker than functionalised frustules, suggesting that physiochemical attributes influence their biodistribution. Our results show that diatom frustules are non cytotoxic and are promising materials to better understand the role of silica in bone healing.

M3 - Abstract

ER -

Walsh P, Clarke S, Julius M, Buchanan F, Messersmith PB. Marine Biosilica as a Tool to Understand the Therapeutic Benefit of Silica in Bone Repair. 2015. Abstract from 6th International Conference on Mechanics of Biomaterials and Tissues, Waikoloa, United States.