## 1 Introduction  
Lab-on-chips (LOCs) and organ-on-chips (OOCs) are revolutionising the healthcare field by making preventive medicine more affordable [1; 2]. Due to their ability to miniaturise laboratory processes and physiological functions on microdevices, both microfluidic technologies are at the forefront of biomedical research and diagnostics [3], driving demand for customised medical devices [4]. Certainly, the COVID-19 pandemic, alongside vaccination campaigns and the investigation of biological markers to identify subjects at an elevated risk of hospitalisation [5; 6], has accelerated the translation of microfluidic solutions from laboratory to commercial applications through LOC devices for point-of-care [7; 8]. In this context, several technologies have been developed and their applications have been extended to various medical fields [9; 10], but microfluidics has emerged as a key technology in translating proof of concepts from research laboratories to commercial applications [11]. However, the transition of microfluidic devices from lab prototypes to large-scale production poses several challenges due to the gap between academia and industry [12]. Once a prototype has been developed, the shift to mass production often requires a deep revision of the design, as the materials and technologies used are completely different from prototype fabrication [13; 14]. To address this, researchers are investigating rapid and flexible production techniques to meet the growing demand for customised devices crucial for precise disease detection and treatment [15; 16; 17]. A more focused industrial prototyping approach, based directly on a large-scale process, could be the novel strategy necessary to bridge academic research to the market. Most biomedical microdevices are typically fabricated using PDMS, glass, or silicon through soft lithography or MEMS techniques. However, thermoplastics are preferred for industrial scaling purposes [18] and, recently, polymers such as cyclic olefin copolymer (COC), polymethylmethacrylate (PMMA), and polypropylene (PP) have become widespread materials due to their lower investment costs, specialised knowledge required, transparency, biocompatibility, and high electrical and chemical resistivity [19]. In this context, manufacturing technologies such as cold casting, micromachining, laser ablation, 3D printing, and thermoforming (including injection moulding and hot embossing) are commonly used for the fabrication of LOCS and OOCs, as reported in Table 1[20; 21; 22]. When it comes to industrial-scale production, however, microinjection moulding (\(\upmu\)IM) seems to be the best performing industrial manufacturing process for high-volume polymeric parts with features below 100 nm and high surface quality replication [23]. Thanks to its high productivity and cost-effectiveness, \(\upmu\)IM has also attracted interest in microfluidic manufacturing and it has become a technology highly valued by researchers for the production of affordable medical chips in recent years [24; 25]. Micro injection moulding, like standard injection moulding, is a manufacturing process that typically employs a steel mould as tool for producing polymeric parts. The tool is a pivotal element in the replication and production process chain, containing the negative geometry of the actual part. The combination of the material and manufacturing technologies to produce an insert, as a tool for a mould, can affect the efficiency, life cycle capabilities, and required lead times for tooling production [29]. In recent years, soft tooling has emerged as novel approach, alongside hard tooling, for the rapid fabrication of mould inserts, despite having limited cycle capacity [30]. Although metallic inserts such as stainless steel, nickel, and bulk metallic glass are preferred for moulding devices with micro-structures and precise surface features like LOC [31], these materials do not allow rapid tooling for \(\upmu\)IM, a crucial factor for the effective prototyping and scaling of products.