Gold nanoshells (~160 nm in diameter) were encapsulated within a shell of temperature-responsive poly(-isopropylacrylamide--acrylic acid) (P(NIPAM--AA)) using a surface-bound rationally-designed free radical initiator in water for the development of a photothermally-induced drug-delivery system. The morphologies of the resultant hydrogel-coated nanoshells were analyzed by scanning electron microscopy (SEM), while the temperature-responsive behavior of the nanoparticles was characterized by dynamic light scattering (DLS). The diameter of the P(NIPAM--AA) encapsulated nanoshells decreased as the solution temperature was increased, indicating a collapse of the hydrogel layer with increasing temperatures. In addition, the optical properties of the composite nanoshells were studied by UV-visible spectroscopy. The surface plasmon resonance (SPR) peak of the hydrogel-coated nanoshells appeared at ~800 nm, which lies within the tissue-transparent range that is important for biomedical applications. Furthermore, the periphery of the particles was conjugated with the model protein avidin to modify the hydrogel-coated nanoshells with a fluorescent-tagged biotin, biotin-4-fluorescein (biotin-4-FITC), for colorimetric imaging/monitoring.
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http://dx.doi.org/10.3390/gels4020028 | DOI Listing |
Nano Lett
October 2021
Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, Texas 78712, United States.
Although dry eye is highly prevalent, many challenges exist in diagnosing the symptom and related diseases. For this reason, anionic hydrogel-coated gold nanoshells (AuNSs) were used in the development of a label-free biosensor for detection of high isoelectric point tear biomarkers associated with dry eye. A custom, aldehyde-functionalized oligo(ethylene glycol)acrylate (Al-OEGA) was included in the hydrogel coating to enhance protein recognition through the formation of dynamic covalent (DC) imine bonds with solvent-accessible lysine residues present on the surface of select tear proteins.
View Article and Find Full Text PDFGels
March 2018
Department of Chemistry and the Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5003, USA.
Gold nanoshells (~160 nm in diameter) were encapsulated within a shell of temperature-responsive poly(-isopropylacrylamide--acrylic acid) (P(NIPAM--AA)) using a surface-bound rationally-designed free radical initiator in water for the development of a photothermally-induced drug-delivery system. The morphologies of the resultant hydrogel-coated nanoshells were analyzed by scanning electron microscopy (SEM), while the temperature-responsive behavior of the nanoparticles was characterized by dynamic light scattering (DLS). The diameter of the P(NIPAM--AA) encapsulated nanoshells decreased as the solution temperature was increased, indicating a collapse of the hydrogel layer with increasing temperatures.
View Article and Find Full Text PDFThe dependence of the localized surface plasmon resonance (LSPR) of noble-metal nanomaterials on refractive index makes LSPR a useful, label-free signal transduction strategy for biosensing. In particular, by decorating gold nanomaterials with molecular recognition agents, analytes of interest can be trapped near the surface, resulting in an increased refractive index surrounding the nanomaterial, and, consequently, a red shift in the LSPR wavelength. Ionic poly( N-isopropylacrylamide- co-methacrylic acid) (PNM) hydrogels were used as protein receptors because PNM nanogels exhibit a large increase in refractive index upon protein binding.
View Article and Find Full Text PDFACS Biomater Sci Eng
August 2015
Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States.
Nanoparticle drug delivery carriers that can modulate drug release based on an exogenous signal, such as light, are of great interest, especially for improving cancer therapy. A light-activated delivery vehicle was fabricated by synthesizing a thin, thermally responsive poly(-isopropylacrylamide--acrylamide) hydrogel coating directly onto the surfaces of individual near-infrared (NIR) absorbing gold-silica nanoshells. This hydrogel was designed to be in a swollen state under physiological conditions and expel large amounts of water, along with any entrapped drug, at elevated temperatures.
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