Use of Hyaluronan‐Derived Hydrogels for Three‐Dimensional Cell Culture and Tumor Xenografts

Abstract

The practice of in vitro three‐dimensional (3‐D) cell culture has lagged behind the realization that classical two‐dimensional (2‐D) culture on plastic surfaces fails to mirror normal cell biology. Biologically, a complex network of proteins and proteoglycans that constitute the extracellular matrix (ECM) surrounds every cell. To recapitulate the normal cellular behavior, scaffolds (ECM analogs) that reconstitute the essential biological cues are required. This unit describes the 3‐D cell culture and tumor engineering applications of Extracel, a novel semisynthetic ECM (sECM), based on cross‐linked derivatives of hyaluronan and gelatin. A simplified cell encapsulation and pseudo‐3‐D culturing (on top of hydrogels) protocol is provided. In addition, the use of this sECM as a vehicle to obtain tumor xenografts with improved take rates and tumor growth is presented. These engineered tumors can be used to evaluate anticancer therapies under physiologically relevant conditions. Curr. Protoc. Cell Biol. 40:10.14.1‐10.14.21. © 2008 by John Wiley & Sons, Inc.

A hydrogel bioink toolkit for mimicking native tissue biochemical and mechanical properties in bioprinted tissue constructs

“…These materials have been implemented in several bioprinting applications [7,9,11], as well as numerous other applications regenerative medicine, including acceleration of angiogenesis [27], adipose tissue engineering [28,29], vocal fold and bone repair [30][31][32][33], 3-D cell expansion and recovery [34], and engineering of tumor xenografts [35][36][37]. By incorporating additional features, the application of this hydrogel for 3-D biofabrication can be significantly extended.…”

Photocrosslinkable Hyaluronan-Gelatin Hydrogels for Two-Step Bioprinting

“…[19][20][21][22][23][24][25][26] The ease with which 3D tissue culture can be performed in vitro and in vivo has made this biomaterial appropriate for new tissue engineering research applications such as development of bladder tissues, centrifugally cast vessel-like tubes, and tumor xenograft models for drug and discovery. 14,18,[27][28][29][30][31][32] Despite these many applications, however, the polyethylene glycol diacrylate (PEGDA)-crosslinked thiolated HA-based sECMs were found to be unsuitable for bioprinting. Because they could not maintain structural integrity during printing and would frequently clog the print heads, a new crosslinking chemistry was needed.…”

Gel Encapsulation of Glucose Nanosensors for Prolonged In Vivo Lifetime

“…Gel 1 and gel 2 were selected for these studies because they can be easily modified for stiffness through dilution, 18,19 and they are amenable to nanosensor incorporation during the gelling process. Three parameters were used to assess and downselect the optimal formulations for in vivo testing: encapsulation efficiency of the nanosensors, glucose permeability through the gel, and nanosensor retention within the gel over time.…”

“…Each gel has applications in cell encapsulation and tumor growth models. 17,18 Gels were prepared according to the manufacturer's instructions and diluted with nanosensors and PBS according to the ratios in Tables 1 and 2 to a total volume of 300 µl. The gelling agents were allowed to gel in a 31 G insulin syringe for at least 20 and 90 min for gel 1 and gel 2, respectively.…”

“…In the case of both gels, dilution of the gel components with the nanosensors and PBS decreases their stiffness. 18,19 To serve as a control for no gel, nanosensors were diluted with only PBS to a final volume of 300 µl.…”