The study evaluates the photopolymerization of poly(ethylene glycol) diacrylate (PEGDA) using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as a photoinitiator, compared to the commonly used I2959. LAP is found to have higher water solubility and better absorption at wavelengths suitable for cell encapsulation, leading to faster gelation times and higher cell viability. The polymerization rate of PEGDA with LAP is significantly faster than with I2959, especially at 365 nm light exposure. LAP also allows for visible light polymerization at lower initiator concentrations and longer wavelengths, which is advantageous for various applications. Cell survival rates for human neonatal fibroblasts encapsulated in PEGDA hydrogels polymerized with LAP are over 95%, demonstrating its cytocompatibility. The study concludes that LAP is a promising photoinitiator for cell encapsulation due to its improved properties over I2959.The study evaluates the photopolymerization of poly(ethylene glycol) diacrylate (PEGDA) using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as a photoinitiator, compared to the commonly used I2959. LAP is found to have higher water solubility and better absorption at wavelengths suitable for cell encapsulation, leading to faster gelation times and higher cell viability. The polymerization rate of PEGDA with LAP is significantly faster than with I2959, especially at 365 nm light exposure. LAP also allows for visible light polymerization at lower initiator concentrations and longer wavelengths, which is advantageous for various applications. Cell survival rates for human neonatal fibroblasts encapsulated in PEGDA hydrogels polymerized with LAP are over 95%, demonstrating its cytocompatibility. The study concludes that LAP is a promising photoinitiator for cell encapsulation due to its improved properties over I2959.