Collagen Hydrogel Containing Polyethylenimine‐Gold Nanoparticles for Drug Release and Enhanced Beating Properties of Engineered Cardiac Tissues

Abstract

Cardiac tissue engineering is a promising strategy to prevent heart failure. However, several issues remain unsolved, including efficient electrical coupling and incorporating factors to enhance tissue maturation and vascularization. Herein, a biohybrid hydrogel that enhances beating properties of engineered cardiac tissues and allows drug release concurrently is developed. Gold nanoparticles (AuNPs) with different sizes (18–241 nm) and surface charges (33.9–55.4 mV) are synthesized by reducing gold (III) chloride trihydrate using branched polyethyleneimine (bPEI). These nanoparticles increase gel stiffness from ≈91 to ≈146 kPa, enhance electrical conductivity of collagen hydrogels from ≈40 to 49–68 mS cm−1, and allow slow and steady release of loaded drugs. Engineered cardiac tissues based on bPEI‐AuNP‐collagen hydrogels and either primary or human induced pluripotent stem cell (hiPSC)‐derived cardiomyocytes show enhanced beating properties. hiPSC‐derived cardiomyocytes exhibit more aligned and wider sarcomeres in bPEI‐AuNP‐collagen hydrogels compared to collagen hydrogels. Furthermore, the presence of bPEI‐AuNPs result in advanced electrical coupling evidenced by synchronous and homogenous calcium flux throughout the tissue. RNA‐seq analyses are in agreement with these observations. Collectively, this data demonstrate the potential of bPEI‐AuNP‐collagen hydrogels to improve tissue engineering approaches to prevent heart failure and possibly treat diseases of other electrically sensitive tissues.

Direct 3D‐Bioprinting of hiPSC‐Derived Cardiomyocytes to Generate Functional Cardiac Tissues

“…We and others have previously demonstrated the suitability of collagen hydrogels for cardiac tissue engineering. [ 16,29 ] While collagen‐hydrogels are difficult to print once gelled, pre‐gel solutions of collagen can be printed into a support bath ( Figure a). [ 24,30 ]…”

“…[14][15][16]37] Current approaches have one or more limitation such as the use of human embryonic stem cell-derived cardiomyocytes, lack of functionality and drug responsiveness, signs of arrhythmia, or/and requirement of a thick shell structure (several 100 μm thick). To generate cardiac ventricles with physiologically relevant pump function, it is important to apply approaches utilized in cast tissues to enhance in the future contractility, such as utilizing an optimal hiPSC line, incorporation of other cell types (e.g., fibroblasts), [16] electroconductive materials, [29,32,38] and pro-proliferative factors, [35] as well as electrical and mechanical stimulation [14] or metabolic maturation. [39,40] In addition, new protocols are needed to enhance the maturation of hiPSC-CMs.…”

“…We and others have previously demonstrated the suitability of collagen hydrogels for cardiac tissue engineering. [16,29] While collagen-hydrogels are difficult to print once gelled, pre-gel solutions of collagen can be printed into a support bath (Figure 1a). [24,30] This so-called in-gel printing requires a support bath that on one hand provides enough stability to retain the printed liquid ink's shape and on the other hand allows the printing nozzle to pass through the support bath.…”

“…This concentration was chosen, as we have previously successfully generated functional cardiac tissues utilizing casting with this concentration of hiPSC-CMs. [29,32] Furthermore, it has previously been reported that the native heart contains 10 to 28 Mio CMs per mL. [33,34] Notably, other studies have used densities of 100 or 300 Mio CMs per mL.…”

Improving the development of human engineered cardiac tissue by gold nanorods embedded extracellular matrix for long-term viability

“…These findings align with previous reports where incorporating gold nanoparticles into ECM scaffolds promotes cell survival and retention. 35,48,49 Fig. 2b shows representative optical transmission images (side and top views) of the GNR-hECTs at day 16 and 9 months.…”