**5. Conclusions**

stem cells, which cannot be killed by these therapies. These cancer stem cells are able to form new colonies and regenerate tumors. It is of great importance to develop new therapeutic approaches to selectively target stem cells. There are novel therapies using NPs to target stem cell-specific markers or signaling pathways [69]. In other hand, glioblastoma multiforme tumors show resistance to radiotherapy and chemotherapy and this is believed to happen due to tumor stem cells. NPs carrying antitumor drugs have to be able to reach the tumor cell, by crossing a series of membranes slide across the blood-brain barrier. For NPs to reach the tumor in a specific way, some strategies have been incorporated like the use of antibodies or peptide molecules which recognize tumor cells antigens to improve the therapeutic efficacy

**Figure 4.** Photographs of controlled thermal burns untreated and treated with CTS/AgNPs nanocomposites.

36 Tissue Regeneration

by means of increasing tumor cell uptake and accumulation into the cytoplasm [70].

NPs, acting as neuroprotectors without cytotoxic effects [73].

In other hand, Gilbert and Osterhout suggested the use of NPs from the delivery of chondroitinase ABC in rats, a therapeutic enzyme to treat spinal cord injury in order to cause axon regenerative responses. In this case, the released enzyme from NPs produced digestion of chondroitin sulfate proteoglycans, which are the lesion markers [71]. For spinal cord injuries, it has been reported the use of biocompatible polymer NPs based on poly(lactic-co-glycolic) encapsulated methylprednisolone, which can reduce the possible neurological deficits after spinal cord procedures, considering ultralow drug doses at local delivery [72]. Another route to treat spinal cord disease is by using cerium oxide NPs. In this regard, Das et al. report the anti-oxidant, photocatalytic and biocompatibility behavior of nanomolar concentration of

Cancer therapy is a major challenge in order to design alternatives for detection and treatment. In particular, the use of aptasensors is emerging as a novel strategy for cancer detection. Aptasensors described as recognition elements derived from artificial fragments of DNA or RNA, easily synthesized and modified to target as biomarkers, with low immunogenicity and high affinity. In this regard, graphene nanocomposites decorated with metallic NPs obtained from Layer by Layer deposition have been considered a novel tool for specific polypeptides detection [74].

For drug delivery systems, Sahu et al. [75] proposed the use of graphene nanosheets integrated into liposomes as drug delivery vehicles, monitored by NIR light. Some advantages of using NIR light to liposomes detection are their non-toxicity, specificity, and high tissue In the present chapter, the use of biopolymers-based nanostructures is addressed, including biomaterials and stem cells, bio-nanocomposites, and specific clinical cases where these systems were employed. We addressed the current challenges in the formulation of functional materials based on biopolymers/metal NPs to mimic the cellular behavior of living organisms. It is important to note that material functionality must be improved to synergistic properties, for example, combined antibacterial/tissue regeneration responses, aiming to contribute the specific cell regeneration and avoiding the bacterial colonization. In this sense, the recent trend in nanomaterials development must be focused in the design of functional systems which combine their physic-chemical and biological characteristics, aiming to produce efficient cellular growth and contribute to tissue engineering approaches. We emphasize the future challenges and perspectives in the design of biocompatible and nontoxic nanocomposites with high efficiency as a promoter for tissue regeneration and many other biomedical applications.
