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Frontiers in Biomedical Engineering

DOI: 10.1002/adfm.202005265 For the imaging community in BME, this issue features two articles discussing the development and application of imaging technologies in drug discovery and delivery (Weissleder and coworkers; article number 1910369) and intraoperative imaging (Achilefu and co-workers; article number 2000185). Advanced imaging systems and molecular probes have not only enabled a mechanistic understanding of the underlining molecular signatures of pathological lesions in their native environments but also provided the means to diagnose and prognose diseases non-invasively. They are now playing an increasingly insightful role in monitoring the efficacy and safety during drug development, such as pharmacokinetics and pharmacodynamics studies. Another fast-growing research area is intraoperative imaging, capable of guiding surgeons to remove lesions with precision beyond what palpation can achieve. This is particularly useful for finding tumors near the resection boundaries. With the recent advances in optics and hardware miniaturization, intraoperative imaging is moving from the conventional bulky instruments towards low-cost hands-free wearable devices. For bioengineers working in the field of nanomedicine and microsystems, this issue features three exciting articles contributed by Matt Trau, Shana Kelley, and John Rogers. Nanoand micro-structures are of considerable current interest, not only because of their unique size-dependent properties but also their dimensional similarities with biological macromolecules (e.g., nucleic acids and proteins) and tissues (e.g., blood vessels). These similarities could allow the integration of nanotechnology, microfabrication, and biology, leading to major advances in medical diagnostics and surveillance. Trau and co-workers (article number 1909306) focus their discussions on the rational design and implementation of miniaturized systems driven by clinical needs. As the next wave of research in micro/nanomaterial-based systems likely will occur in clinical translation, this article reviews the technologies that have been robustly tested on real patient samples and discusses the recent paradigm shift towards integrated multi-omics cancer signature analysis. Kelley and co-workers (article number 1907701) summarize the remarkable achievements in nanomaterials synthesis, where nanostructures of different sizes, shapes, surfaces, topologies, and combinations can be made with precision. This capability in materials engineering has enabled biological sensing both in vitro and inside cells. More interestingly, biosensor development in BME has advanced beyond research and clinical laboratory tests and started making an impact on one of the key elements in next-generation healthcare, digital health, where wearable monitoring systems can provide valuable insights about the state of wellness, performance, and disease progression. In addition to the conventional limited biophysical markers, Rogers and co-workers (article number 1907269) discuss recent advances in skin-interfaced microfluidics, stretchable/flexible electronics, and mechanics that have enabled new Biomedical engineering (BME) is one of the youngest disciplines in engineering and one of the most interdisciplinary exercises integrating advances in physical sciences (physics, mathematics, chemistry, and materials science), biological and medical sciences (molecular biology, immunology, physiology, and neurology), and engineering (instrumentation and data science). Although the modern era of BME started 60–70 years ago, problem-solving for wellness and happiness is a natural instinct of human beings, whose bioengineering inventions stretched back as far as human history itself (e.g., the Egyptian prosthetic wooden and leather toe and the fermentation process). Modern BME is the bridge between medicine and engineering, a dynamic duo that has produced many transformative technologies from early inventions including the dialysis machine, pacemaker, artificial heart valve, CT scanner, and portable electrocardiography machine, to the more recent ones such as immuno-engineering, genome engineering, and wearable devices. These inventions are direct results of the recent advancements in medicine and engineering, which happen to share a similar timeline: the success of genetic analysis highlighted by Watson-Crick’s DNA model discovered in the 1950s that put medical research in the fast lane, and the explosive growth of engineering marked by the computing powers and data analysis capabilities (from the ENIAC in the 1940s to personal computers in the 1970s). The significance of this medicine–engineering duet where medicine provides the needs and motivations and engineering helps device solutions is fully illustrated by the current outbreak of the COVID-19 pandemic. The SARS-CoV-2 infection is mainly diagnosed via CT imaging of the lung and PCR-based molecular tests, whereas serologic assays based on point-of-care (POC) lateral flow devices can detect the presence of IgG and/ or IgM against SARS-CoV-2, which indicates immunity at least for a short term. Improved technologies for mass surveillance of the spread of infections (e.g., rapid tests and wearable biosensors) and mass screening of the population that have the antibodies are key to the gradual reopening of society. Towards therapy and vaccine, research in BME is equally active at both academic research institutes and the biotech industry. Bioengineers are working hard on designing neutralizing antibodies and engineering RNA sequences and delivery technologies for a SARS-CoV-2 vaccine. The medical imaging, point-of-care device, immuno-engineering, and drug delivery technologies used against COVID-19 are excellent examples of a plethora of technologies related to BME that have changed and are still improving lives. In this Special Issue, we cannot list them all. Instead, we highlight a few, hoping to stimulate the readers’ interest and help advance the field. Frontiers in Biomedical Engineering