Health sciences

Micromagnets dispersed in a polymer matrix are used to realize a soft magnetoelastic generator with high magnetomechanical coupling factor, used for wearable and implantable power generation and sensing applications.

A functional interfacial material has been developed for soft integration of bioelectronic devices with biological tissues. This has been applied in battery-free optoelectronic systems for deep-brain optogenetics and subdermal phototherapy as well as wireless millimetre-scale pacemakers and flexible multielectrode epicardial arrays.

This Review highlights the approaches that have been utilized in the implementation of sensory feedback onto prosthetic devices to restore the sensation of touch and proprioception for amputees.

The basement membrane stiffness is shown to be a more dominant determinant than pore size in regulating cancer cell invasion, metastasis formation and patient survival. This stiffness is now known to be affected by the ratio of netrin-4 to laminin, with more netrin-4 leading to softer basement membranes.

Extrusion-based bioprinting has been shown to rapidly and reproducibly generate kidney organoids from a cell-only paste, with the number and maturation of functional units within the kidney tissue capable of being further improved by bioprinting tissue sheets.

Lamin mutations responsible for muscular dystrophy are shown to reduce nuclear envelope stability, resulting in mechanically induced nuclear envelope rupture, DNA damage and activation of DNA damage response pathways that lead to muscle cell death. Preventing nuclear envelope damage by reducing cytoskeletal forces on the nucleus improves muscle fibre health and function.

Imbalance of the gut microbiome has been implicated in numerous human diseases. Nanoparticles have now been designed to target colitis by modulating the gut microbiome, local innate immune response and restoration of the intestinal barrier function.

Foreign body response can result in failure of biomaterials in vivo. Solvent-free crystals containing anti-fibrotic drugs now show the potential for long-term inhibition of fibrosis on a number of implantable devices in rodents and non-human primates.

The extracellular matrix surrounding cells plays a significant role in their behaviour. The spreading, mechanosensing and differentiation of mesenchymal stem cells are shown to be dependent on the early deposition and remodelling of local nascent proteins within degradable and viscoelastic hydrogels.

Microparticle wear debris from prosthetic implants following patient revision surgery is observed to induce a potent type 2 inflammatory response involving cytokine secretion by macrophages through a Bruton’s tyrosine kinase-dependent signalling pathway.

The Zika virus infects the central nervous system and results in severe brain malformation. An amphiphatic peptide is now shown to penetrate the blood–brain barrier, reducing viral loads due to its activity against Zika and other mosquito-borne viruses.

Islet transplantation for diabetes treatment requires immunosuppression to control rejection. A microgel presenting Fas ligand with immunomodulatory properties is now shown to prolong the survival of allogeneic islet grafts in vivo.

Immunotherapy offers a promising approach to treating a range of complications. This Review discusses strategies that employ bioengineering and immunological principles to develop engineered tissues for screening therapeutics and treating diseases.

Mechanical cues play critical roles in embryonic development. A micropatterned neuroectoderm developmental model based on human pluripotent stem cells now reveals how morophogenetic signals such as cell shape and contractility regulate neural tissue development.

Molecular simulations reveal the self-assembly of small molecules into nanoparticle drug carriers. Targeting of colon and liver cancer cells by the nanoparticles via kinase inhibitors is employed in anti-tumour therapy in vivo.

Antiviral nanoparticle-formulated mimics of heparan sulfate proteoglycans were developed and shown to permit strong viral association as well as inhibition of a range of viruses on in vitro and in vivo models of infection.

Metallic stents have been widely used in coronary angioplasty. Here, the authors develop a resorbable self-expanding stent from polymeric elastomers with high mechanical strength for coronary applications.

Tissue mimics are of great interest in understanding diseases. Here, organoids were developed that resemble polycystic kidney disease cysts and it was demonstrated how material environment and adhesion can affect cystogenesis and disease progression.

By studying the immune responses of animals to different types of biomaterial implants, colony stimulating factor-1 receptor is revealed as an important mediator of the foreign body reaction and a possible target for fibrosis inhibition.

A retinal prosthesis fabricated from an organic photovoltaic polymer can restore degenerative blindness in vivo, and over long implantation periods.

A high-throughput hydrogel-based platelet-contraction cytometer is able to quantify single-platelet contraction forces and may function as a clinical diagnostic biophysical biomarker.

A hydrogel patch delivering a combination of gene, drug and phototherapy leads to complete tumour remission and the absence of tumour recurrence in a colon cancer mouse model.

Lipid nanoparticles incorporating proteins from the leukocyte plasma membrane retain the properties of liposomal formulations and enable delivery of drugs to inflamed tissues.

Analytical techniques reveal that spherical calcium phosphate particles are the first mineralized structures to be formed in the calcification process in cardiovascular tissues. Furthermore, the inner sections of calcified lesions in patients with various cardiovascular diseases are identified as highly crystalline, spherical hydroxyapatite particles that differ in structure from bone mineral.

An electrochemical method that uses ion-selective membranes to electrically modulate ion concentrations in situ along a sciatic nerve in vitro allows for on-demand reversible inhibition of signal propagation as well as up to 40% reduction of the electrical threshold for stimulation. The method may be applicable in implantable neuroprosthetic devices.

The in vivo optical detection of bacterial infections requires highly specific imaging probes with small affinity to mammalian tissue. It is now shown that fluorescent dyes that are conjugated to maltohexaose can be internalized rapidly via the bacteria-specific maltodextrin transport pathway, enabling the in vivo imaging of Escherichia coli down to 10⁵ colony-forming units.

A nanocarrier—synthesized by the fusion of liposomes to spherical, nanoporous silica particles and subsequent modification of the lipid bilayer with targeting peptides and fusogenic peptides—shows the targeted delivery and controlled release of chemically diverse multicomponent cargos within the cytosol of certain cancer cells.

Inflatable balloon catheters are widely used in many surgical and diagnostic procedures. Such catheters have now been used as a platform for a collection of components including semiconductor devices, sensors and actuators, and these multifunctional catheters probed for their use in cardiac-related applications.