Progress in the development of piezoelectric biomaterials for tissue remodeling

Piezoelectric biomaterials have demonstrated significant potential in the past few decades to heal damaged tissue and restore cellular functionalities. Herein, we discuss the role of bioelectricity in tissue remodeling and explore ways to mimic such tissue-like properties in synthetic biomaterials. In the past decade, biomedical engineers have adopted emerging functional biomaterials-based tissue engineering approaches using innovative bioelectronic stimulation protocols based on dynamic stimuli to direct cellular activation, proliferation, and differentiation on engineered biomaterial constructs. The primary focus of this review is to discuss the concepts of piezoelectric energy harvesting, piezoelectric materials, and their application in soft (skin and neural) and hard (dental and bone) tissue regeneration. While discussing the prospective applications as an engineered tissue, an important distinction has been made between piezoceramics, piezopolymers, and their composites. The superiority of piezopolymers over piezoceramics to circumvent issues such as stiffness mismatch, biocompatibility, and biodegradability are highlighted. We aim to provide a comprehensive review of the field and identify opportunities for the future to develop clinically relevant and state-of-the-art biomaterials for personalized and remote health care.

Surface nanocrystallization enhances the biomedical performance of additively manufactured stainless steel

Additive manufacturing enables the fabrication of patient-specific implants of complex geometries. Although selective laser melting (SLM) of 316L stainless steel (SS) is well established, post-processing is essential to preparing high-performance biomedical implants. The goal of this study was to investigate surface mechanical attrition treatment (SMAT) as a means to enhance the electrochemical, biomechanical, and biological performances of 316L SS fabricated by SLM in devices for the repair of bone tissues. The SMAT conditions were optimized to induce surface nanocrystallization on the additively manufactured samples. SMAT resulted in a thicker oxide layer, which provided corrosion resistance by forming a passive layer. The fretting wear results showed that the rate of wear decreased after SMAT owing to the formation of a harder nanostructured layer. Surface modification of the alloy by SMAT enhanced its ability to support the attachment and proliferation of pre-osteoblasts in vitro. The study of the response in vivo to the additively manufactured alloy in a critical-sized cranial defect murine model revealed enhanced interactions with the cellular components after the alloy was subjected to SMAT without inducing any adverse immune response. Taken together, the results of this work establish SMAT of additively manufactured metallic implants as an effective strategy for engineering next-generation, high-performance medical devices for orthopedics and craniomaxillofacial applications.

'Template-free' hierarchical MoS2 foam as a sustainable 'green' scavenger of heavy metals and bacteria in point of use water purification

Molybdenum disulfide (MoS₂), with its unique optical and electrical properties, has been explored for a variety of applications in the recent past. Still, its capabilities in point-of-use heavy metal ion removal remain to be explored. Herein, for the first time using a facile approach, we fabricated three-dimensional (3D) MoS₂ foam from exfoliated single to few-layered MoS₂ sheets for the selective exclusion of heavy metals and stringent bactericidal response. This foam was able to exclude 99.9% of Pb(ii) and 98.7% of As(iii) instantaneously and reduced more than 98% of bacteria E. coli. Moreover, the foam exhibits selective toxicity towards bacterial cells while showing no observable toxicity towards mammalian cells. The foam can be recycled and reused for at least five cycles under accelerated conditions and thus can be used for a promising non-cytotoxic, facile, and environmentally benign process for inline water remediation to remove heavy metal ions from the feed and as a potential antibacterial agent.

Effects of a multi-strain Bacillus species-based direct-fed microbial on growth performance, nutrient digestibility, blood profile, and gut health in nursery pigs fed corn-soybean meal-based diets

This experiment was conducted to investigate the effect of a spp.-based direct-fed microbial (DFM) on growth performance, apparent total tract digestibility (ATTD), blood profile, intestinal histomorphology, and fecal gas emission in piglets fed corn and soybean meal-based diets. The DFM product was based on 1 strain of and 2 strains of and formulated to supply 1.5 × 10 cfu/g of feed. A total of 128 piglets ([Yorkshire × Landrace] × Duroc; 6.8 ± 0.6 kg BW; weaning age: 24 d) were housed in groups (4 pigs/pen, 2 barrows and 2 gilts) and fed diets ( = 16) without or with DFM in a 2-phase feeding program: d 0 to 14 (phase I) and 15 to 42 (phase II). Feed intake and BW were measured weekly. At the end of each phase, samples for blood urea nitrogen (BUN), blood creatinine, ATTD, and fecal noxious gas emission were taken. At termination, 12 piglets per treatment were killed to access intestinal tissues for histomorphology. Overall, pigs fed DFM had a greater ( < 0.05) G:F than pigs fed the control diet. In phase I, pigs fed DFM showed a greater ( < 0.05) ADG and lower ( < 0.05) concentration of BUN and fecal ammonia emission than the control group. In phase II, a greater ( < 0.05) ATTD of nitrogen and longer ( < 0.05) duodenum and jejunum villi were observed in pigs fed the DFM diet compared with the control group. In conclusion, inclusion of DFM improved growth performance and villi length of the duodenum and jejunum in nursery pigs. Furthermore, DFM enhanced protein utilization as demonstrated by increased nitrogen digestibility, lower BUN, and lower fecal ammonia release.