As biomaterials transition from static, inert objects into dynamic scaffolds that augment the healing process, the ability to design large-scale changes in architecture in response to environmental changes is increasingly valuable. To address this need, stimuli-responsive, or "smart," biomaterials are employed in clinical applications more frequently. These materials are capable of undergoing large and abrupt changes in shape in response to small changes in the environment, such as temperature, pH, mechanical forces, light, magnetic fields, or enzymes. Smart polymeric biomaterials include shape memory polymers, stimuli-responsive hydrogels, and liquid crystal elastomers. These materials are used in a vast range of biomedical applications, including embolic/hemostatic devices, orthopedics, cosmetics, wound healing, drug delivery, neural scaffolds, and infection control, among others. While smart materials can be employed in vitro for biomedical uses, we focus here on materials that have been designed for use in or on the human body. The signals that these materials respond to include those that occur endogenously in vivo and externally applied signals that are controlled by clinicians and/or patients. This review highlights current clinically available devices based on smart materials, smart polymeric biomaterial technologies that are in current clinical trials, and novel materials that are under development for future clinical use.

Cancer therapies such as chemotherapy, radiopharmaceutical therapy, and transarterial embolization rely on effective drug or radiation delivery through the bloodstream. Understanding how various drugs and particles, which form and size span multiple scales, are transported through blood and tissue is essential for optimizing treatment. Computational fluid dynamics (CFD) is a powerful tool to simulate blood flow and drug transport, solving flow governing equations under biologically realistic conditions. This review explores CFD applications in cancer therapy, focusing on transarterial embolization, tumor perfusion, and organ-on-a-chip systems. In radioembolization, CFD can predict microsphere transport and dose distribution to spare vital functions. Tumor perfusion modeling and organ-on-a-chip systems benefit from CFD by replicating vascular dynamics and drug dispersion. Despite its versatility and established mechanical principles, CFD faces challenges, including the need for patient-specific data, computational demands, and multiscale modeling. This review highlights opportunities for integrating CFD with imaging modalities and artificial intelligence tools to overcome these barriers and advance personalized cancer treatment.

We review how sensorimotor control is dictated by interacting neural populations, optimal feedback mechanisms, and the biomechanics of bodies. First, we outline the distributed anatomical loops that shuttle sensorimotor signals between cortex, subcortical regions, and spinal cord. We then summarize evidence that neural population activity occupies low-dimensional, dynamically evolving manifolds during planning and execution of movements. Next, we summarize literature explaining motor behavior through the lens of optimal control theory, which clarifies the role of internal models and feedback during motor control. Finally, recent studies on embodied sensorimotor control address gaps within each framework by aiming to elucidate neural population activity through the explicit control of musculoskeletal dynamics. We close by discussing open problems and opportunities: multitasking and cognitively rich behavior, multiregional circuit models, and the level of anatomical detail needed in body and network models. Together, this review and recent advances point toward reaching an integrative account of the neural control of movement.

The continuous, real-time measurement of specific molecules in situ in the body promises to revolutionize the precision of drug dosing, the reach of physiological research, and the accuracy and timeliness of clinical diagnostics. Motivated by these prospects, here we critically review the set of molecular sensing technologies that (a) have been demonstrated to support seconds-resolved measurements in mammalian subjects and (b) appear translatable to the clinic. The relevant technologies employ four readout modalities: (a) direct or enzymatic electrochemical detection, (b) indirect electrochemical detection, (c) optical strategies, and (d) photoacoustic sensing. For each, we analyze the engineering requirements to support real-time, in vivo operation-which include reversibility, reagentless interrogation, and selectivity-and the remaining barriers to clinical adoption, including sensitivity and long-term in vivo stability and biocompatibility. Collectively, the advances surveyed here suggest that seconds-resolved molecular monitoring in humans is within reach and will herald a new era of precision diagnostics and closed-loop therapeutics.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent hepatic pathology worldwide, with significant potential for progression to cirrhosis and ultimately end-stage liver disease. Accordingly, a wide range of preclinical models have been developed to better understand the disease mechanisms and progression as well as to accelerate drug discovery. These include in vitro, ex vivo, and in vivo models, which offer unique advantages yet differ in terms of disease driver, species used, and biological complexity-ranging from benchtop cellular systems to whole organs and organisms. In this review, we provide a comprehensive overview of the technologies currently used for the study of MASLD, with a focus on how standardization of disease progression across models may aid therapeutic development.

Type 1 diabetes (T1D) is a chronic condition in which patients suffer from high blood glucose levels due to the body's inability to produce sufficient insulin. Continuous insulin administration and T1D management are difficult, often leading to hypoglycemic events, insulin resistance, and lower quality of life. Major advancements have been made in recent years, including clinical islet transplantation, but their application is limited by rapid immune rejection and islet destruction. Thus, a necessary paradigm shift has been observed in recent times toward biomaterial-based islet transplantation therapy. The use of biomaterial-based encapsulation addresses major limitations, including immune rejection and hypoxia, and provides a proper cell microenvironment offering greater islet viability. Presently, researchers are more focused on developing a clinically translatable therapy for T1D with the existing knowledge of advanced biomaterial technology. In this review article, we provide a historical perspective, highlighting the developments in the field of islet encapsulation and transplantation, and focus on cutting-edge advancements with modern bioengineering from a clinical perspective.

Acrolein is a highly reactive α,β-unsaturated aldehyde produced endogenously through lipid peroxidation and enzymatic metabolism and exogenously via environmental exposures. Acrolein covalently adducts to DNA and proteins, leading to oxidative stress, mitochondrial dysfunction, and inflammation, including innate immune response activation via natural antibodies. Acrolein is difficult to measure in biological systems, but acrolein-bound covalent products can be measured reliably. Therapeutically, nucleophilic small molecules that scavenge acrolein such as hydralazine, phenelzine, dimercaprol, carnosine, and N-acetylcysteine (NAC) have shown neuroprotective effects in animal models of multiple sclerosis, Parkinson's disease, spinal cord injury, and traumatic brain injury. These effects include preserved membrane and mitochondrial integrity, reduced inflammation, reduced pain, and improved motor, sensory, and cognitive outcomes. Alternative strategies that enhance clearance or inhibit production of acrolein show promise but face limitations. Acrolein is a key pathophysiological mediator and a viable therapeutic target in central nervous system trauma and neurodegenerative diseases.

The rise in popularity of two-photon polymerization (TPP) as an additive manufacturing technique has impacted many areas of science and engineering, particularly those related to biomedical applications. Compared with other fabrication methods used for biomedical applications, TPP offers 3D, nanometer-scale fabrication dexterity (free-form). Moreover, the existence of turnkey commercial systems has increased accessibility. In this review, we discuss the diversity of biomedical applications that have benefited from the unique features of TPP. We also present the state of the art in approaches for patterning and reading 3D TPP-fabricated structures. The reading process influences the fidelity for both in situ and ex situ characterization methods. We also review efforts to leverage machine learning to facilitate process control for TPP. Finally, we conclude with a discussion of both the current challenges and exciting opportunities for biomedical applications that lie ahead for this intriguing and emerging technology.

Medical ultrasound is a diagnostic imaging modality used for visualizing internal organs; the frequencies typically used are 2-10 MHz. Scanning acoustic microscopy (SAM) is a form of ultrasound where frequencies typically exceed 50 MHz. Increasing the acoustic frequency increases the specimen's spatial resolution but reduces the imaging depth. The advantages of using SAM over conventional light and electron microscopy include the ability to image cells and tissues without any preparation that could kill or alter them, providing a more accurate representation of the specimen. After scanning the specimen, acoustic signals are merged into an image on the basis of changes in the impedance mismatch between the immersion fluid and the specimens. The acoustic parameters determining the image quality are absorption and scattering. Surface scans can assess surface characteristics of the specimen. SAM is also capable of elastography, that is, studying elastic properties to discern differences between healthy and affected tissues. SAM has significant potential for detection/analysis in research and clinical studies.

The microvasculature, a complex network of small blood vessels, connects systemic circulation with local tissues, facilitating the nutrient and oxygen exchange that is critical for homeostasis and organ function. Engineering these structures is paramount for advancing tissue regeneration, disease modeling, and drug testing. However, replicating the intricate architecture of native vascular systems-characterized by diverse vessel diameters, cellular constituents, and dynamic perfusion capabilities-presents significant challenges. This complexity is compounded by the need to precisely integrate biomechanical, biochemical, and cellular cues. Recent breakthroughs in microfabrication, organoids, bioprinting, organ-on-a-chip platforms, and in vivo vascularization techniques have propelled the field toward faithfully replicating vascular complexity. These innovations not only enhance our understanding of vascular biology but also enable the generation of functional, perfusable tissue constructs. Here, we explore state-of-the-art technologies and strategies in microvascular engineering, emphasizing key advancements and addressing the remaining challenges to developing fully functional vascularized tissues.