The primary objective of this article is twofold: to address the key concept of topology that impacts materials science in a major way and to convey the excitement to the materials community of recent significant advances in our understanding of the important topological notions in a wide class of materials with potential technological applications. A paradigm of topology/geometry → property → functionality is emerging that goes beyond the traditional microscopic structure → property → functionality relationship. The new approach delineates the active roles of topology and geometry in design, fabrication, characterization, and predictive modeling of novel materials properties and multifunctionalities. After introducing the essentials of topology and geometry, we elucidate these concepts through a gamut of nanocarbon allotropes of de novo carbons, hierarchical self-assembled soft- and biomaterials, supramolecular assemblies, and nanoporous materials. Applications of these topological materials range from sensing, energy storage/conversion, and catalysis to nanomedicine.

The ability of cancer-targeted nanoparticles (NPs) to reach their site of action and evoke a desired biological response after intravenous injection is critical to achieve clinically significant in vivo efficacy. Throughout their journey in the body, NPs must successfully traverse biological environments such as blood circulation and tumor microenvironments. The interactions that occur at the interface between NPs and biological components are complex, requiring a thorough understanding of the “nano-bio” interactions to design NPs with maximal therapeutic indices. In this article, we review the challenges presented by the multiscale, important biocompartments that NPs face, describe the crucial nano-bio interactions present at each stage, and discuss potential strategies to overcome those challenges. This review suggests design considerations for NPs to optimally modulate their physicochemical properties to achieve desired biological responses, which are expected to aid chemists, engineers, and clinical scientists to design and develop highly effective delivery platforms for cancer therapy.

After a decade of active research, pressure is mounting for clinical translation of nanomedicines. However, to enable success in the clinic, it is important to understand the factors that can pose challenges. For example, reduction in adverse effects alone might not be enough of a driver today for clinical translation. The benchmark for clinical translation will be increased efficacy, a significant challenge to overcome if nanomedicines are developed only from a drug delivery perspective. Success in clinics will therefore require a re-examination of the design of nanomedicines, including challenging current dogmas. What can we learn from translational experience with recently approved antibody-drug conjugates, which like nanomedicines is another approach to deliver chemotherapy agents selectively to the tumors? Nanomedicines can address some of the emerging challenges in cancer chemotherapy, including heterogeneity and adaptive resistance, which can offer unique translational opportunities. This article addresses some of these themes and strategies that can facilitate translation of nanomedicines to the clinic.

Nanotechnology has had a huge impact on the development of therapeutics over the last couple of decades. To date, a large number of organic nanoparticles have been developed to encapsulate and deliver therapeutic and imaging agents. These nanoparticles have allowed encapsulation and targeted release of drugs. A few nanoparticle-based drugs are already being used in patients, and several others are making excellent progress toward clinical translation. The strong pipeline of therapeutic nanoparticles is fueled by advances in novel materials and design features, new applications, and a better understanding of fundamental hurdles that limit the utility of nanoparticles. The articles in this issue of MRS Bulletin are focused on some of the significant recent advances in the use of organic nanoparticles for drug delivery and imaging.

CuInS2 thin films with thickness ranging from 196 to 1000 nm were prepared from a source containing CuInS2 nanocrystals by using thermal evaporation method. Annealed films of CuInS2 show the quasi-amorphous to crystalline phase transition, probed through x-ray diffraction (XRD), UV-visible spectrometer, and Raman spectroscopy. From XRD, the tetragonal distortion (η) is found to be ≈1, confirming the arrangement of an extended double lattice structure of chalcopyrite phase. The surface morphology of quasi-amorphous film exhibits a very smooth surface, whereas crystalline film shows a very rough surface of CuInS2 as observed from atomic force microscopy. Crystallite size and rms roughness increase from 23 to 310 nm and from 1.5 to 36.5, respectively, with increasing film thickness as well as with increasing annealing temperature due to the crystallization process. Micro-Raman study evidencing the presence of a strong Raman A1 mode at 303 cm−1, due to the symmetric vibration of anion sublattice of CuInS2 structure. A fundamental band edge is observed in as-deposited quasi-amorphous CuInS2 films, while bulk energy band absorption and excitonic band transition are observed in crystalline films. A sharp drop in both reflectance and transmittance near the energy band gap region is observed in thick films due to a very strong absorption of crystalline phase of CuInS2.

An electro-acoustic method for measuring volume charge distributions in dielectric films (50 μm–0.2 mm thick) is described. A high voltage (>1 kV) sinusoidal signal (frequency ∼ 2 kHz) is applied across the dielectric sample. The charges inside the dielectric material will mechanically respond to the input electric signal and excite acoustic waves. The acoustic waves can be detected and measured using a piezoelectric sensor. By analyzing the received acoustic signal, we are able to compare the amount of charge in various samples.

In this study, 3 mol% Y2O3-stabilized zirconia (3Y–ZrO2) and commercially pure titanium (cp-Ti) joints were fabricated with an Ag68.8Cu26.7Ti4.5 interlayer (Ticusil) at 900 °C for various brazing periods. After brazing at 900 °C/0.1 h, Ti2Cu, TiCu, Ti3Cu4, and TiCu4 layers were present at the Ti/Ticusil interface, while TiCu and TiO layers were observed at the Ticusil/3Y–ZrO2 interface. In the residual interlayer, clumpy TiCu4 was formed along with the Ag solid phase. After brazing at 900 °C/1 h, Ti3Cu3O and Ti2O layers were formed at the interlayer/ZrO2 interface, while Cu2O was precipitated in the residual interlayer with $\left[ {111} \right]_{{\rm{Cu}}_{\rm{2}} {\rm{O}}} //\left[ {111} \right]_{{\rm{Ag}}}$ and $\left( {20\bar 2} \right)_{{\rm{Cu}}_{\rm{2}} {\rm{O}}} //\left( {20\bar 2} \right){}_{{\rm{Ag}}}$ . After brazing at 900 °C/6 h, a two-phase (α-Ti + Ti2Cu) region was observed on the Ti side with $\left[ {2\bar 1\bar 10} \right]_{{\rm{\alpha - Ti}}} //\left[ {100} \right]_{{\rm{Ti}}_{\rm{2}} {\rm{Cu}}}$ and $\left( {0002} \right)_{{\rm{\alpha - Ti}}} //\left( {0\bar 13} \right)_{{\rm{Ti}}_{\rm{2}} {\rm{Cu}}}$ , while the TiCu layer grew at the expense of Ti3Cu4 and TiCu4. The bonding mechanisms and diffusion paths were explored with the aid of Ag–Cu–Ti and Ti–Cu–O ternary phase diagrams.