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Zhao, Heng; Heindel, Ned D.

doi:10.1023/a:1015866104055

Cited by 355 publications

(167 citation statements)

References 7 publications

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“…40 Oxidation degree was confirmed by a hydroxylamine hydrochloride titration assay. 69 Lyophilized dextran-aldehyde was reconstituted in 1 mL of water to the desired concentration (typically 200 mg/mL). Similarly, generation 5 poly(amidoamine) dendrimers with 25% amine surface groups (Dendritech) were diluted to the desired concentration (typically 246 mg/mL) and concentrated hydrochloric acid was used to bring pH to the desired level (typically 9.2).…”

Section: Methodsmentioning

confidence: 99%

Hydrogel Nanocomposites with Independently Tunable Rheology and Mechanics

et al. 2017

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Hydrogels are an attractive class of biomaterials for minimally invasive local drug delivery given their injectability, tunability, high water content, and biocompatibility. Broad applicability though is challenged: relatively modest mechanical properties restricts use to soft tissues, while flow properties necessary for injectability limit implantation to dried, enclosed tissues to minimize material migration during gelation. To address these dual concerns we designed an injectable nanocomposite hydrogel based on dextran aldehyde and poly(amido amine) dendrimer doped with phyllosilicate nanoplatelet fillers. Balance of components allows for exfoliation of nanoplatelets, significantly changing macromer solution flow, facilitating injection and manipulation in a wide variety of implantation contexts while enhancing compressive modulus of hydrogels at low loading. Importantly, rheological and mechanical effects were dependent on aspect ratio, with high aspect ratio nanoplatelets having much stronger effects on mechanics and low aspect ratio nanoplatelets having stronger effects on rheology; enabling nearly independent control of rheological and mechanical properties. Nanoplatelets enhanced hydrogel properties at substantially lower filler loading than comparably sized nanoparticles. We present a model to explain the role that aspect ratio plays in control of rheology and mechanics in nanoplatelet-containing hydrogels, with lessons for further nanocomposite hydrogel development. This low cost biocompatible material may be useful as a drug delivery platform in challenging implantation environments.

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Section: Methodsmentioning

confidence: 99%

Hydrogel Nanocomposites with Independently Tunable Rheology and Mechanics

et al. 2017

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“…After dialysis, oxidized chondroitin sulfate was lyophilized for one week and stored in the fridge prior to use. The degree of substitution (percentage of potential hydroxyl side groups on the CS converted to aldehyde groups) was measured through hydroxylamine hydrochloride titration using the procedure and calculations described by Zhao et al [52]. …”

Section: Methodsmentioning

confidence: 99%

Thermogelling bioadhesive scaffolds for intervertebral disk tissue engineering: Preliminary in vitro comparison of aldehyde-based versus alginate microparticle-mediated adhesion

et al. 2015

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Tissue engineering of certain load-bearing parts of the body can be dependent on scaffold adhesion or integration with the surrounding tissue to prevent dislocation. One such area is the regeneration of the intervertebral disc (IVD). In this work, poly(N-isopropylacrylamide) (PNIPAAm) was grafted with chondroitin sulfate (CS) (PNIPAAm-g-CS) and blended with aldehyde-modified CS to generate an injectable polymer that can form covalent bonds with tissue upon contact. However, the presence of the reactive aldehyde groups can compromise the viability of encapsulated cells. Thus, liposomes were encapsulated in the blend, designed to deliver the ECM derivative, gelatin, after the polymer has adhered to tissue and reached physiological temperature. This work is based on the hypothesis that the discharge of gelatin will enhance the biocompatibility of the material by covalently reacting with, or “end-capping”, the aldehyde functionalities within the gel that did not participate in bonding with tissue upon contact. As a comparison, formulations were also created without CS aldehyde and with an alternative adhesion mediator, mucoadhesive calcium alginate particles. Gels formed from blends of PNIPAAm-g-CS and CS aldehyde exhibited increased adhesive strength compared to PNIPAAm-g-CS alone (p<0.05). However, the addition of gelatin-loaded liposomes to the blend significantly decreased the adhesive strength (p<0.05). The encapsulation of alginate microparticles within PNIPAAm-g-CS gels caused the tensile strength to increase two-fold over that of PNIPAAm-g-CS blends with CS aldehyde (p<0.05). Cytocompatibility studies indicate that formulations containing alginate particles exhibit reduced cytotoxicity over those containing CS aldehyde. Overall, the results indicated that the adhesives composed of alginate microparticles encapsulated in PNIPAAm-g-CS have the potential to serve as a scaffold for IVD regeneration.

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“…Periodate oxidized glucan particles ( n = 5 samples) were evaluated for aldehyde content using a hydroxylamine hydrochloride assay [34]. Oxidized GP samples (5 mg) were incubated in 1 mL of DMSO at 50°C for 2 h to dissolve the particles.…”

Section: Methodsmentioning

confidence: 99%

Glucan Particles for Macrophage Targeted Delivery of Nanoparticles

Soto

Caras

Kut

et al. 2012

Journal of Drug Delivery

113

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Glucan particles (GPs) are hollow, porous 2–4 μm microspheres derived from the cell walls of Baker's yeast (Saccharomyces cerevisiae). The 1,3-β-glucan outer shell provides for receptor-mediated uptake by phagocytic cells expressing β-glucan receptors. GPs have been used for macrophage-targeted delivery of soluble payloads (DNA, siRNA, protein, and small molecules) encapsulated inside the hollow GPs via core polyplex and layer-by-layer (LbL) synthetic strategies. In this communication, we report the incorporation of nanoparticles as cores inside GPs (GP-NP) or electrostatically bound to the surface of chemically derivatized GPs (NP-GP). GP nanoparticle formulations benefit from the drug encapsulation properties of NPs and the macrophage-targeting properties of GPs. GP nanoparticle formulations were synthesized using fluorescent anionic polystyrene nanoparticles allowing visualization and quantitation of NP binding and encapsulation. Mesoporous silica nanoparticles (MSNs) containing the chemotherapeutic doxorubicin (Dox) were bound to cationic GPs. Dox-MSN-GPs efficiently delivered Dox into GP phagocytic cells resulting in enhanced Dox-mediated growth arrest.

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Untitled

Cited by 355 publications

References 7 publications

Hydrogel Nanocomposites with Independently Tunable Rheology and Mechanics

Hydrogel Nanocomposites with Independently Tunable Rheology and Mechanics

Thermogelling bioadhesive scaffolds for intervertebral disk tissue engineering: Preliminary in vitro comparison of aldehyde-based versus alginate microparticle-mediated adhesion

Glucan Particles for Macrophage Targeted Delivery of Nanoparticles

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