The Know4Nano project is funded under the HORIZON-WIDERA-2023-ACCESS-02 programme, Grant Agreement No. 101159710 with aims to strengthen knowledge and skills transfer for the application of bionanotechnology in the development of biosensors for pathogen detection in food safety. The project brings together the BioSense Institute (BIOS) and three leading EU research institutions whose complementary expertise in biosensors and nanotechnology is leveraged to develop advanced biosensing platforms applicable along the farm-to-fork food chain. By establishing a structured knowledge transfer framework based on staff exchanges, trainings, and joint research activities, Know4Nano supports the improvement of research excellence at BIOS, while simultaneously strengthening long-term collaboration and strategic networking among the partners. Through targeted mobilities and hands-on training activities, BIOS researchers acquire essential competencies in nanomaterials, biosensors, microfluidics, food safety, and research management, thereby expanding their individual research profiles and enhancing the institutional research capacity and visibility of all involved partners.Within this framework, Work Package 3 (WP3) focuses on the organization, implementation, and monitoring of structured staff exchange activities and targeted trainings among the project partners. WP3 encompasses carefully planned expert visits, mentor visits, extended stay visits, and short stay visits, supported by defined pre- and post-visit procedures to ensure effective knowledge and skills transfer. Activities under WP3 are implemented covering both organizational and administrative support, expert, and mentor exchanges, extended hands-on research stays, and short, task-oriented research visits aimed at fabrication, testing, and validation of nanomaterials, biosensors, and experimental protocols. Scientific and administrative trainings not directly linked to WP3 staff exchange activities (such as participation in external workshops, conferences, or training programmes) fall outside the scope of this deliverable and are reported under other WP2 and WP4.This deliverable, D3.1. Report on Staff Exchange, Trainings and Knowledge & Skills Transfer documents the WP3 activities implemented during the first phase of the project. It provides an overview of the conducted expert, mentor, extended stay, and short stay visits, including the associated trainings, joint research activities, and capacity-building actions carried out between BIOS and the partner institutions. The report summarizes the scope, content, and implementation status of WP3 activities, serving as a basis for monitoring progress, evaluating the effectiveness of knowledge transfer, and guiding subsequent staff exchange and collaboration actions within the Know4Nano research project.