## 7 Conclusions and Future Perspectives  
Although the research field of BGs for neuroregeneration is still in its beginning, these bioactive materials have shown great promise for the treatment of peripheral nerve and spinal cord injuries. For this purpose, silicate-, phosphate-, and borate-based BGs have been mainly proposed in the form of fibers and/or combined with soft polymers for the development of tubular devices to promote axonal directional growth. At present, BGs have proved suitable to repair small-to-mid peripheral nerve defects (typically \(<\) 2 cm) in animal models, but researchers have not experimented in human patients yet. Looking at the question posed in the manuscript title, the answer is \"yes\"--we should be hopeful about the use of BGs in this new and partially unexplored scenario. The challenges to be tackled in the future will concern the improvement of tissue regeneration even for long nerve gaps, as well as investigation of the potential suitability of BG-based biomaterials in the repair of cranial nerves. The implementation of additive manufacturing technologies (AMTs), which have already been widely applied in bone tissue engineering [94], will indeed carry significant added value in this field, too. In fact, AMTs allow for (i) achieving accurate control of the geometry/porosity of the biomaterial/scaffold/fibrous construct and (ii) combining different biomaterials (e.g., BGs, polymers) and even cells, which can be printed simultaneously (biofabrication [95]). Selection of the basic glass composition along with appropriate therapeutic dopants will be key to postoperative success. Metallic dopants can affect the chemical stability of the glass network and, hence, the BG reactivity in contact with biological fluids. In this regard, the resorption of the BG-based conduit should be comparable to that of nerve regeneration. Furthermore, the ion dissolution products released from BGs can have a direct effect on neural cell activity via pH variations and/or signaling pathway activation. At present, there is a paucity of studies on this topic; some ions, such as Ga\({}^{3+}\) and Zn\({}^{2+}\), seem to have stimulatory effects on neurons [58], but the biomolecular picture is still profoundly incomplete due to the complexity of interactions among the multiple ions which are typically released from BGs (not only the dopants but also silicate and phosphate species, Ca\({}^{2+}\), and Na\({}^{+}\)). The common components of BG structures are generally recognized to be safe for the human body. Although there have been no specific studies addressing the neuroregeneration scenario, the available results are quite promising. [PERSON] et al. [96] described the removal pathways of silicon from silicate BG granules implanted in rabbits over a six-month follow-up period and analyzed the animal brain, heart, kidney, liver, lung, lymph nodes, spleen, and thymus by using biochemical and histopathological assays. It was shown that the average excretion rate of silicon was 2.4 mg/day, and all the implanted silicon was excreted by 19 weeks after implantation. No increased concentration of silicon ions was detected at the implant site (rabbit paraspinal muscle) or in the internal organs/structures mentioned above after 24 weeks, and no abnormal histological appearance was detected. It was also reported that both silicon derived from implanted silicate BG and boric acid derived from implanted borate BG are harmlessly excreted from the body through urine in metabolic processes [97; 98]. Specific metallic cations with the ability to activate the signaling pathways involved in peripheral nerve regeneration deserve to be incorporated in BGs and investigated in the near future. Mg\({}^{2+}\) ions were reported to promote the expression of nerve growth factor (NGF) and neurotrophic factor 3 (NTF3) in Schwann cells [99]. Strontium [100] and gadolinium [101] can activate the Ras/MAPK and PI3K/Akt signaling pathways, respectively.