R&D Factor Mobility and Regional Collaborative Innovation: Empirical Data from China’s Yangtze River Delta Region

The flow of R&D factors serves as a crucial channel for linking regional collaborative innovation resources and plays a significant role in promoting spatial knowledge spillovers, making it an important engine for the in-depth implementation of innovation-driven development strategies. This study takes the Yangtze River Delta urban agglomeration as its research object, utilizing data from 2003-2023, and employs gravity models and dynamic spatial fixed effects models to analyse the impact of R&D factor flows on regional collaborative innovation, as well as the moderating role of intellectual property protection. The study revealed that both the flow of R&D personnel and R&D capital significantly promote regional collaborative innovation, with the flow of R&D capital playing a more prominent role. The intensity of intellectual property protection positively moderates the relationship between the flow of R&D factors and regional collaborative innovation, but a single threshold effect exists, where the moderating effect weakens after exceeding the threshold. The intensity of inter-city collaborative innovation continues to increase, with core cities such as Shanghai, Hangzhou, and Nanjing playing a significant leading role. The emergence of new central cities such as Nantong, Ningbo, and Jiaxing has driven the evolution of collaborative innovation toward a "star-shaped" structure. The mechanism for the flow of R&D factors should be optimized, the intensity of intellectual property protection should be balanced, collaborative innovation between core cities and emerging central cities should be strengthened, and regional innovation infrastructure construction should be enhanced to promote high-quality innovative development in the Yangtze River Delta region.