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William M Reichert - One of the best experts on this subject based on the ideXlab platform.

  • microencapsulation of 2 octylcyanoacrylate tissue adhesive for self healing acrylic bone cement
    Journal of Biomedical Materials Research Part B, 2012
    Co-Authors: Alice B W Brochu, William J Chyan, William M Reichert
    Abstract:

    Here, we report the first phase of developing self-healing acrylic bone cement: the preparation and characterization of polyurethane (PUR) microcapsules containing a medical cyanoacrylate tissue adhesive. Capsules were prepared by interfacial polymerization of a toluene-2,4-diisocyanate-based polyurethane prepolymer with 1,4-butanediol to encapsulate 2-octylcyanoacrylate (OCA). Various capsule characteristics, including: resultant morphology, average size and size distribution, shell thickness, content and reactivity of encapsulated agent, and shelf life are investigated and their reliance on solvent type and amount, surfactant type and amount, temperature, pH, agitation rate, reaction time, and mode of addition of the oil phase to the aqueous phase are presented. Capsules had average diameters ranging from 74 to 222 μm and average shell thicknesses ranging from 1.5 to 6 μm. The capsule content was determined via thermogravimetric analysis and subsequent analysis of the capsules following up to 8 weeks storage revealed minimal loss of core contents. Mechanical testing of OCA-containing capsules showed individual capsules withstood compressive forces up to a few tenths of Newtons, and the contents released from crushed capsules generated tensile adhesive forces of a few Newtons. Capsules were successfully mixed into the poly(- methyl methacrylate) bone cement, surviving the mixing process, exposure to methyl methacrylate monomer, and the resulting exothermic matrix curing.

Alice B W Brochu - One of the best experts on this subject based on the ideXlab platform.

  • microencapsulation of 2 octylcyanoacrylate tissue adhesive for self healing acrylic bone cement
    Journal of Biomedical Materials Research Part B, 2012
    Co-Authors: Alice B W Brochu, William J Chyan, William M Reichert
    Abstract:

    Here, we report the first phase of developing self-healing acrylic bone cement: the preparation and characterization of polyurethane (PUR) microcapsules containing a medical cyanoacrylate tissue adhesive. Capsules were prepared by interfacial polymerization of a toluene-2,4-diisocyanate-based polyurethane prepolymer with 1,4-butanediol to encapsulate 2-octylcyanoacrylate (OCA). Various capsule characteristics, including: resultant morphology, average size and size distribution, shell thickness, content and reactivity of encapsulated agent, and shelf life are investigated and their reliance on solvent type and amount, surfactant type and amount, temperature, pH, agitation rate, reaction time, and mode of addition of the oil phase to the aqueous phase are presented. Capsules had average diameters ranging from 74 to 222 μm and average shell thicknesses ranging from 1.5 to 6 μm. The capsule content was determined via thermogravimetric analysis and subsequent analysis of the capsules following up to 8 weeks storage revealed minimal loss of core contents. Mechanical testing of OCA-containing capsules showed individual capsules withstood compressive forces up to a few tenths of Newtons, and the contents released from crushed capsules generated tensile adhesive forces of a few Newtons. Capsules were successfully mixed into the poly(- methyl methacrylate) bone cement, surviving the mixing process, exposure to methyl methacrylate monomer, and the resulting exothermic matrix curing.

William J Chyan - One of the best experts on this subject based on the ideXlab platform.

  • microencapsulation of 2 octylcyanoacrylate tissue adhesive for self healing acrylic bone cement
    Journal of Biomedical Materials Research Part B, 2012
    Co-Authors: Alice B W Brochu, William J Chyan, William M Reichert
    Abstract:

    Here, we report the first phase of developing self-healing acrylic bone cement: the preparation and characterization of polyurethane (PUR) microcapsules containing a medical cyanoacrylate tissue adhesive. Capsules were prepared by interfacial polymerization of a toluene-2,4-diisocyanate-based polyurethane prepolymer with 1,4-butanediol to encapsulate 2-octylcyanoacrylate (OCA). Various capsule characteristics, including: resultant morphology, average size and size distribution, shell thickness, content and reactivity of encapsulated agent, and shelf life are investigated and their reliance on solvent type and amount, surfactant type and amount, temperature, pH, agitation rate, reaction time, and mode of addition of the oil phase to the aqueous phase are presented. Capsules had average diameters ranging from 74 to 222 μm and average shell thicknesses ranging from 1.5 to 6 μm. The capsule content was determined via thermogravimetric analysis and subsequent analysis of the capsules following up to 8 weeks storage revealed minimal loss of core contents. Mechanical testing of OCA-containing capsules showed individual capsules withstood compressive forces up to a few tenths of Newtons, and the contents released from crushed capsules generated tensile adhesive forces of a few Newtons. Capsules were successfully mixed into the poly(- methyl methacrylate) bone cement, surviving the mixing process, exposure to methyl methacrylate monomer, and the resulting exothermic matrix curing.

Elazer R Edelman - One of the best experts on this subject based on the ideXlab platform.

  • aldehyde amine chemistry enables modulated biosealants with tissue specific adhesion
    Advanced Materials, 2009
    Co-Authors: Natalie Artzi, Tarek Shazly, Aaron B Baker, Adriana Bon, Elazer R Edelman
    Abstract:

    Soft-tissue surgical sealants provide an ideal material class for assessment of tissue–material interactions. Sealant adhesion can be rigorously quantified through a series of functional assays that supplement characterizations of tissue reactivity and material fate. A collection of experimental techniques can be exploited to elucidate mechanistic aspects of tissue–material interactions with general implications, extending beyond the immediate scope of adhesive materials. Moreover, though sealants are routinely used in clinical procedures, active questions and limitations force physicians to choose between extremes of adhesion strength and biocompatibility. [1] Common cyanoacrylate derivatives adhere strongly to tissue, but their vigorous and uncontrolled tissue crosslinking along with the release of toxic degradation by-products dramatically impedes healing and regeneration processes. [2] The polymerization of alkylcyanoacrylates occurs via anionic and zwitterionic polymerizations in the presence of weak bases such as alcohols, water, and amino acids encountered in living tissues. [3] Cyanoacrylates with short side alkyl chains (methyl or ethyl) rapidly degrade to form cyanoacetate and formaldehyde, characterized by acute and chronic inflammation. The longer alkyl chains degrade slower, resulting in more limited accumulation of toxic byproducts that may be effectively eliminated by tissues. Histotoxicity depends on the vascularity of tissues, being greater in well-vascularized soft tissues. [4] Fibrin glues represent the opposite polar extreme along the spectrum of sealants [4] eliciting a mild tissue response, but with relatively non-specific and minimally adhesive tissue interaction. [5–7] Though these and all sealants rely on intimate tissue–material interactions for functional adhesion, target-tissue properties have been largely ignored in material design. Instead, one general formulation is proposed for application to the full range of soft tissues across diverse clinical applications. [8–13] Here, we demonstrate that aldehyde-mediated adhesion to tissue strongly depends on target-tissue type and state, and propose a rational approach for the engineering of application-specific surgical sealants. Copolymeric hydrogels featuring aminated star polyethylene glycolandhigh-molecular-weight dextranaldehyde(PEG:dextran) possess a series of physico-chemical properties that can be modified to create a family of materials with tunable tissue adhesion. [14–17] The two polymer constituents of PEG:dextran were prepared as minimally viscous aqueous solutions and consistently polymerized through injection from a dual chamber syringe equipped with a mixing tip. [15,16] The cohesive integrity of PEG:dextran is derived from imine bonds that form through a Schiff base reaction between amines and aldehydes. [14–17] When crosslinked on soft-tissue surfaces, aldehydes not consumed in bulk network formation form analogous bonds with tissue amines to achieve adhesion. Aldehydes in excess of what is required for cohesion or adhesion can induce tissue toxicity. [18] Consequently, material aldehyde density is the key design parameter for informative evaluation of tissue-material adhesion and tissue response. We designed and evaluated a series of PEG:dextran formulations featuring low (8.8%, abbreviated L-PD), medium (14.0%, abbreviated M-PD), and high (20.0%, abbreviated H-PD) levels of dextran aldehyde solid content. Additional design parameters, including dextran molecular weight (10 kDa) and oxidation state (50%), and PEG amine solid content (25%) were identical among formulations, and selected to provide stable and bioreactive networks for evaluation of adhesive

Reichert W.m. - One of the best experts on this subject based on the ideXlab platform.

  • Mechanical properties and biocompatibility of poly(methyl methacrylate) bone cement containing microencapsulated tissue adhesive
    2013
    Co-Authors: Brochu A.b.w., Evans G.a., Reichert W.m.
    Abstract:

    One of the most broadly reported self-healing schemes is that pioneered by White and Sottos et al. in which a polymer matrix is co-embedded with a catalyst and microcapsules containing a reactive healing agent. Although this field has been steadily growing over the past 10 years, little discussion of extension into biomaterials has taken place and none of the existing systems employ materials acceptable for in vivo applications. Due to its long history of use, lack of postpolymerization modifications, and susceptibility to fatigue failure, poly(methyl methacrylate) (PMMA) bone cement is an attractive option for the first self-healing biomaterial designed utilizing the aforementioned embedded capsule and catalyst approach. Interfacial polymerization of a polyurethane prepolymer with 1,4-butanediol was performed to encapsulate 2-octyl cyanoacrylate (OCA), an FDA-approved tissue adhesive, using an oil-in-water emulsion. The compressive, tensile, and fracture toughness properties of commercial PMMA matrices containing various wt% of capsules were investigated. The proliferation and viability of MG63 human osteosarcoma cells following various exposure times to extracts from OCA, capsuleembedded bone cement, and bone cement without capsules were also examined. Incorporation of greater than 5 wt% capsules reduced the compressive and tensile strengths below commercially-accepted standards for bone cement. Fracture toughness, K, was increased by 13% with the inclusion of 3 wt% capsules but was decreased below the control value with contents of 15 wt% and higher. Additionally, cellular viability and proliferation were similar in cells exposed to media conditioned with commercial and capsule-embedded bone cements, suggesting the addition of capsules to the bone cement does not have a detrimental effect on the toxicity of the material