This study illustrates the sensing and wound healing properties of silk fibroin in combination with peptide patterns, with an emphasis on the printability of multilayered grids, and envisions possible applications of these next-generation silk-based materials. Functionalized silk fibers covalently linked to an arginine–glycine–aspartic acid (RGD) peptide create a platform for preparing a biomaterial ink for 3D printing of grid-like piezoresistors with wound-healing and sensing properties. The culture medium obtained from 3D-printed silk fibroin enriched with RGD peptide improves cell adhesion, accelerating skin repair. Specifically, RGD peptide-modified silk fibroin demonstrated biocompatibility, enhanced cell adhesion, and higher wound closure rates at lower concentration than the neat peptide. It was also shown that the printing of peptide-modified silk fibroin produces a piezoresistive transducer that is the active component of a sensor based on a Schottky diode harmonic transponder encoding information about pressure. We discovered that such biomaterial ink printed in a multilayered grid can be used as a humidity sensor. Furthermore, humidity activates a transition between low and high conductivity states in this medium that is retained unless a negative voltage is applied, paving the way for utilization in non-volatile organic memory devices. Globally, these results pave the way for promising applications, such as monitoring parameters such as human wound care and being integrated in bio-implantable processors.

The pharmacological modulation of collagen turnover is a strategy potentially useful in different skin conditions. The serine protease inhibitor Serpin A1 and portions of its C‐terminal region have been investigated as collagen modulators. To clarify the mechanisms by which the C‐terminal 409‐418 peptide SA1‐III increases extracellular type I collagen levels, to compare its activities range with that of the originator molecule Serpin A1, and to evaluate its efficacy in primary cultures from adult and aged human subjects. The different forms of type I collagen were analyzed by means of western blot in cell lysates and cell‐conditioned media of primary human dermal fibroblasts obtained from subjects of different ages. Gelatin zymography was used to investigate the degrading enzymes. Cell viability and in vitro wound healing tests were used to evaluate cell proliferation. The SA1‐III peptide increased extracellular collagen levels by reducing degradation, with no effect on cellular biosynthesis or cell proliferation mechanisms. A reduced level of MMP‐2 and MMP‐9 was also found in cell media upon peptide treatment. No peptide effect was detected on inflammatory mediators gene expression in resting and LPS‐stimulated fibroblasts, or in the wound healing test. The SA1‐III peptide is a good collagen modulator candidate, protecting collagen against degradation without detectable actions on biosynthesis, acting at reasonably low concentrations, and non‐interfering with cell proliferation. It is effective in primary fibroblasts from young and aged subjects. These effects can prove useful in pathological and physiological skin conditions in which collagen degradation is excessive compared to the synthetic capacity.

Protein therapeutics are extensively used in the treatment of autoimmune diseases, but a subset of patients appears to be refractory to these treatments, mainly due to the development of an immune response to the drug. A better understanding of the mechanism underlying the therapeutic drug’s failure becomes fundamental for the development of new and more effective treatments. Unfortunately, there are few cases where the exact mechanisms through which drugs bypass immunological tolerance and provoke immunogenicity have been studied. In this context, peptide epitope identification gained increasing importance in investigating the molecular mechanism of therapeutic drug’s immune responses. Despite peptide identification and use to monitor anti-drug antibody (ADA) profiles is a promising research field, their use is far away from a wide application both at the research and at the commercial level. Herein it is reported a compilation of studies in which peptides are directly involved in anti-drug immune responses, becoming the molecular key step for a better understanding of refractory reactions in therapeutic drugs. An overview on T-cell and B-cell peptide recognition is given, showing the growing potential and advantages of peptides when used in the field of refractoriness to drugs. This review includes studies describing antigenic peptides that enable enhanced ADA detection directly in patients’ sera, as well as the proof of concept that asses the use of peptides instead of proteins, to facilitate the identification of neutralizing ADA.