ABSTRACT
In this work we explore a new hydrogel stamp material obtained from polymerizing 2-hydroxyethyl acrylate and poly(ethylene glycol) diacrylate in the presence of water for the microcontact printing of proteins directly on gold substrates and by covalent coupling to self-assembled monolayers of alkanethiols. At high cross-link density, the hydrogel is rigid, hydrophilic, and with a high buffer holding capacity to enable the unsupported printing of protein patterns homogeneously and reproducibly, with micrometer-range precision. The stamps were used to print antibodies to human parathyroid hormone, which were shown using immunoassay tests to retain their biological function with binding capacities comparable to those of solution-adsorbed antibodies.
Subject(s)
Acrylates/chemistry , Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry , Parathyroid Hormone/chemistry , Polyethylene Glycols/chemistry , Serum Albumin, Bovine/chemistry , Acrylates/chemical synthesis , Animals , Antibodies/chemistry , Antibodies/immunology , Cattle , Enzyme-Linked Immunosorbent Assay , Gold/chemistry , Humans , Hydrogel, Polyethylene Glycol Dimethacrylate/chemical synthesis , Hydrophobic and Hydrophilic Interactions , Parathyroid Hormone/immunology , Polyethylene Glycols/chemical synthesis , Sensitivity and Specificity , Serum Albumin, Bovine/immunology , Spectrometry, Fluorescence/instrumentation , Spectrometry, Fluorescence/methods , Sulfhydryl Compounds/chemistry , Surface Properties , Water/chemistryABSTRACT
Photodynamic therapy (PDT) is a promising therapeutic modality for treatment of solid tumors. In this study, third-generation aryl ether dendrimer porphyrins (DPs) with either 32 quaternary ammonium groups (32(+)DPZn) or 32 carboxylic groups (32(-)DPZn) were evaluated as a novel, supramolecular class of photosensitizers for PDT. DPs showed a different cell-association profile depending on the positive or negative charge on the periphery, and both DPs eventually localized in membrane-limited organelles. In contrast, protoporphyrin IX (PIX), which is a hydrophobic and relatively low molecular weight photosensitizer used as a control in this study, diffused through the cytoplasm except the nucleus. Confocal fluorescent imaging using organelle-specific dyes indicated that PIX induced severe photodamage to disrupt membranes and intracellular organelles, including the plasma membrane, mitochondrion, and lysosome. On the other hand, cells treated with DPs kept the characteristic fluorescent pattern of such organelles even after photoirradiation. However, notably 32(+)DPZn achieved remarkably higher (1)O(2)-induced cytotoxicity against LLC cells than PIX. Furthermore, both dendrimer porphyrins had far lower dark toxicity as compared with PIX, demonstrating their highly selective photosensitizing effect in combination with a reduced systemic toxicity.
