Multiplexed Dosing Assays by Digitally Definable Hydrogel Volumes

Abstract

Stable and low-cost multiplexed drug sensitivity assays using small volumes of cells or tissue are in demand for personalized medicine, including patient-specific combination chemotherapy. Spatially defined projected light photopolymerization of hydrogels with embedded active compounds is introduced as a flexible and cost-efficient method for producing multiplexed dosing assays. The high spatial resolution of light projector technology defines multiple compound doses by the volume of individual compound-embedded hydrogel segments. Quantitative dosing of multiple proteins with a dynamic range of 1-2 orders of magnitude is demonstrated using fluorescently labeled albumins. The hydrogel matrix results from photopolymerization of low-cost poly(ethylene glycol) diacrylates (PEGDA), and tuning of the PEGDA composition enables fast complete dosing of all tested species. Dosing of hydrophilic and hydrophobic compounds is demonstrated using two first-line chemotherapy regimens combining oxaliplatin, SN-38, 5-fluorouracil, and folinic acid, with each compound being dosed from a separate light-defined hydrogel segment. Cytotoxicity studies using a colorectal cancer cell line show equivalent effects of dissolved and released compounds. Further control of the dosing process is demonstrated by liposomal encapsulation of oxaliplatin, stable embedding of the liposomes in hydrogels for more than 3 months, and heat-triggered complete release of the loaded oxaliplatin.

Stereolithographic hydrogel printing of 3D culture chips with biofunctionalized complex 3D perfusion networks

“…[42][43][44] Our aim is to manufacture the perfusion chip unit surrounding the encapsulated cells, and we consequently selected a medium MW PEGDA to produce mechanically stable, yet diffusion-open, compliant hydrogel constructs. 45 LAP and QY were selected because of their excellent water solubility and low cytotoxicity. 45,46 The photoabsorber was used to limit the light penetration into the pre-polymer solution and thereby to achieve an optical Z resolution of the printer by matching its concentration to the printing process, as discussed in detail below.…”

“…45 LAP and QY were selected because of their excellent water solubility and low cytotoxicity. 45,46 The photoabsorber was used to limit the light penetration into the pre-polymer solution and thereby to achieve an optical Z resolution of the printer by matching its concentration to the printing process, as discussed in detail below. Importantly, printing in aqueous solution minimizes dimensional changes caused by post-printing swelling.…”

Multimaterial hydrogel with widely tunable elasticity by selective photopolymerization of PEG diacrylate and epoxy monomers

“…For the soft part of the material the radical initiated poly (ethylene glycol) diacrylate (PEGDA) (700 Da) was used, as this is known to form soft hydrogels useful in tissue engineering . For the stiff part, the epoxy monomer, 3,4‐epoxycyclohexylmethyl 3,4‐epoxycyclohexanecarboxylate (EEC) turned out to polymerize the fastest compared to other cationic initiated monomers (Table S1 Supporting Information).…”