Volume 2, Issue 2

The successful development of nanomaterials illustrates the considerable interest in the development of new molecular probes for medical diagnosis and imaging. Substantial progress was made in the synthesis protocol and characterization of these materials, whereas toxicological issues are sometimes incomplete. Nanoparticle-based contrast agents (CAs) tend to become efficient tools for enhancing medical diagnostics and surgery for a wide range of imaging modalities. The multimodal nanoparticles (NPs) are much more efficient than the conventional molecular-scale CAs. They provide new abilities for in vivo detection and enhanced targeting efficiencies through longer circulation times, designed clearance pathways, and multiple binding capacities. Properly protected, they can safely be used for the fabrication of various functional systems with targeting properties, reduced toxicity, and proper removal from the body. This review mainly describes the advances in the development of mono- to multimodal NPs and their in vitro and in vivo relevant biomedical applications ranging from imaging and tracking to cancer treatment. Besides the specific applications for classical imaging (magnetic resonance imaging, positron emission tomography, computed tomography, ultrasound, and photoacoustic imaging), the less common imaging techniques such as terahertz molecular imaging (THMI) or ion beam analysis (IBA) are mentioned. The perspectives on the multimodal theranostic NPs and their potential for clinical advances are also mentioned.

Nanoscience studies describe natural phenomena at the submicron scale. Below a critical nanoscale limit, the physical, chemical, and biological properties of materials show a marked departure in their behavior compared to the bulk. At the nanoscale, energy conversion is dominated by phonons, whereas at larger scales, electrons determine the process. The surface-to-volume ratio at the nanoscale is immense, and interfacial interactions are markedly more important than at the macroscopic level, where the majority of the material is shielded from the surface. These properties render the nanoparticles to be significantly different from their larger counterparts. Nano-enabled drug delivery systems have resulted from multidisciplinary cooperation aimed at improving drug delivery. Significant improvements in the thermodynamic and delivery properties are seen due to nanotechnology. Hybrid nanodelivery systems, i.e., membranes with nanopores that can gate stimuli-responsive drug release could be a future development. Nanotechnology will improve current drug delivery and create novel future delivery systems. The fundamental properties and challenges of nanodelivery systems are discussed in this review.

Nanoparticle-based drug delivery is an emerging technology for targeting therapeutics to the diseased site for enhanced therapy and reduced toxicity. A number of pharmaceutical products that involve nanotechnology have been approved for clinical use, and because of altered pharmacokinetics and biodistribution, their profiles of interaction with host cells and resulting toxicity are different from parent agents. This review focuses on the immune responses induced by therapeutic lipid nanoparticles. These immune responses can provoke toxicity, affect pharmacokinetics of the nanoparticles or induce therapeutic effect. This article begins with a general introduction on immune responses and innate and acquired immunity. Specific examples of therapeutic lipid nanoparticles inducing immune responses in each category are presented with detailed discussions on the mechanisms. Current guidelines for evaluating immune response of nanomedicines are summarized. Finally, perspectives and future directions are provided emphasizing mechanistic studies of immune reactions triggered by nanoparticles.

Bioorthogonal chemistries are covalent reaction pairs that proceed in the presence of biological components with complete specificity. A suite of reactions has been described to date that provides scientists and engineers with diverse operational characteristics for different applications. Nanomaterials in particular have benefitted from these new capabilities, resulting in improved coupling efficiencies and multifunctionality. In this review, we will discuss the application of bioorthogonal chemistries to different nanomaterial systems, highlighting the advantages and limitations for use in bioconjugation. We will also describe how recent improvements in the reaction speed of catalyst-free bioorthogonal chemistries have enabled the successful coupling of nanomaterials directly to live cells. Using a recently developed reaction pair, tetrazine and trans -cyclooctene, the direct covalent coupling to cells has been shown to occur on time-scales that are relevant for biological studies and diagnostic applications and can even amplify nanomaterial binding greater than tenfold relative to traditional immunoconjugates. This powerful technique still maintains exquisite specificity, however, yielding robust results in clinical diagnostic applications using human tissue and blood samples. Future work will likely focus on further advancement of the in situ amplification technique, such as increasing nanomaterial binding, enabling multiplexed detection through the use of orthogonal reaction systems and extension to applications in vivo .

Atomic force microscopy has developed from an atomic level imaging technique to a large family of nanoscientific research setups called scanning probe microscopy. Following this trend, we also need to develop our education from instructions to use the instrument for imaging into an approach of deeper understanding of the science behind the technologies. In this article, we describe our new university level scanning probe microscopy laboratory unit to learn the main scientific principles and applications of the instruments. Three inquiries using toy models were designed to cover the core ideas of scanning probe microscopy. Learning outcomes were analyzed and categorized into levels from the research reports of nine students. We found that practically every student learned atomic force imaging basics: scanning and essential properties of the topography image. One-third of the students showed good understanding in image artifacts and probe calibration, but just one of the students reached the level beyond the topography images to scanning force microscopy and combined force and topography techniques in his report. Also, the connection between scanning probe techniques and human senses was considered an important objective in design of this laboratory unit, although with modest success in learning so far.