Application of smart nanostructures in medicine

TiO2 Nanotubes Functionalized with Icariin for an Attenuated In Vitro Immune Response and Improved In Vivo Osseointegration

Due to their superior mechanical and chemical properties, titanium (Ti) and its alloys have been widely used as orthopedic implantable devices. However, their bioinertness represents a limitation, which can be overcome by employing various surface modifications, such as TiO₂ nanotube (TNT) fabrication via electrochemical anodization. Anodic TNTs present tunable dimensions and unique structures, turning them into feasible drug delivery platforms. In the present work, TNTs were loaded with icariin (Ica) through an adhesive intermediate layer of polydopamine (DP), and their in vitro and in vivo biological performance was evaluated. The successful fabrication of the modified surfaces was verified by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements (CA), while the in vitro release of Ica was evaluated via UV-VIS spectrophotometry. In terms of in vitro behaviour, comparative studies on RAW 264.7 macrophages demonstrated that the TNT substrates, especially TNT-DP-Ica, elicited a lower inflammatory response compared to the Ti support. Moreover, the in vivo implantation studies evinced generation of a reduced fibrotic capsule around this implant and increased thickness of the newly formed bone tissue at 1 month and 3 months post-implantation, respectively. Overall, our results indicate that the controlled release of Ica from TNT surfaces could result in an improved osseointegration process.

Evaluating the Toxicity and Histological Effects of Al2O3 Nanoparticles on Bone Tissue in Animal Model: A Case-Control Study

The applications of nanostructures have been limited by their different toxicities. So, the investigation of these toxicities is necessary before nanostructure application. This study aimed to evaluate the effect of aluminum oxide (Al₂O₃) nanoparticles on bone density in Wistar rat. Al₂O₃ nanoparticle was prepared by the sol-gel method. Characterization was done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Sixty-four male adult Wistar rats were divided into eight groups including six groups intravenously treated with Al₂O₃ nanoparticle at concentrations of 25, 50, 100, 250, 500, and 1000 µg/ml: one group received food and water as the control group, and one group received food and water as well as intravenously distilled water as an injection control group. After 41 days, bone density was analyzed by dual-energy X-ray absorptiometry (DEXA). According to X-ray diffraction, the average particle size for Al₂O₃ nanoparticles was 20.85 nm. The data of densitometry showed that the bone density of right and left foot was reduced in concentrations of 250, 500, and 1000 µg/ml that were statistically significant in comparison with the control group. The reduction of bone density was increased with the enhancement of nanostructures concentration. The effect of Al₂O₃ nanoparticles on bone density was similar in the left and right legs. Histopatholological assessment also showed that Al₂O₃ nanoparticles (250, 500, and 1000 µg/ml) lead to significant reduction of trabeculae. Empty lacunae are observed in these three groups. Considering that high concentrations of Al₂O₃ nanoparticles had toxicity on bone tissue, it must be used by more caution, especially its use as a coating in different devices such as implants, surgical instruments, and bone prostheses.

Micro/nanoscale magnetic robots for biomedical applications

Magnetic small-scale robots are devices of great potential for the biomedical field because of the several benefits of this method of actuation. Recent work on the development of these devices has seen tremendous innovation and refinement toward ​improved performance for potential clinical applications. This review briefly details recent advancements in small-scale robots used for biomedical applications, covering their design, fabrication, applications, and demonstration of ability, and identifies the gap in studies and the difficulties that have persisted in the optimization of the use of these devices. In addition, alternative biomedical applications are also suggested for some of the technologies that show potential for other functions. This study concludes that although the field of small-scale robot research is highly innovative ​there is need for more concerted efforts to improve functionality and reliability of these devices particularly in clinical applications. Finally, further suggestions are made toward ​the achievement of commercialization for these devices.

Cell-Inspired All-Aqueous Microfluidics: From Intracellular Liquid-Liquid Phase Separation toward Advanced Biomaterials

Living cells have evolved over billions of years to develop structural and functional complexity with numerous intracellular compartments that are formed due to liquid-liquid phase separation (LLPS). Discovery of the amazing and vital roles of cells in life has sparked tremendous efforts to investigate and replicate the intracellular LLPS. Among them, all-aqueous emulsions are a minimalistic liquid model that recapitulates the structural and functional features of membraneless organelles and protocells. Here, an emerging all-aqueous microfluidic technology derived from micrometer-scaled manipulation of LLPS is presented; the technology enables the state-of-art design of advanced biomaterials with exquisite structural proficiency and diversified biological functions. Moreover, a variety of emerging biomedical applications, including encapsulation and delivery of bioactive gradients, fabrication of artificial membraneless organelles, as well as printing and assembly of predesigned cell patterns and living tissues, are inspired by their cellular counterparts. Finally, the challenges and perspectives for further advancing the cell-inspired all-aqueous microfluidics toward a more powerful and versatile platform are discussed, particularly regarding new opportunities in multidisciplinary fundamental research and biomedical applications.

Digital Assembly of Colloidal Particles for Nanoscale Manufacturing

From unravelling the most fundamental phenomena to enabling applications that impact our everyday lives, the nanoscale world holds great promise for science, technology and medicine. However, the extent of its practical realization would rely on manufacturing at the nanoscale. Among the various nanomanufacturing approaches being investigated, the bottom-up approach involving assembly of colloidal nanoparticles as building blocks is promising. Compared to a top-down lithographic approach, particle assembly exhibits advantages such as smaller feature size, finer control of chemical composition, less defects, lower material wastage, and higher scalability. The capability to assemble colloidal particles one by one or "digitally" has been heavily sought as it mimics the natural way of making matter and enables construction of nanomaterials with sophisticated architectures. This progress report provides an insight into the tools and techniques for digital assembly of particles, including their working mechanisms and demonstrated particle assemblies. Examples of nanomaterials and nanodevices are presented to demonstrate the strength of digital assembly in nanomanufacturing.

DIBc, a nanochelating-based nano metal-organic framework, shows anti-diabetic effects in high-fat diet and streptozotocin-induced diabetic rats

Aims

Despite daily increase in diabetic patients in the world, currently approved medications for this disease, at best, only reduce its progression speed. Using novel technologies is a solution for synthetizing more efficient medicines. In the present study, we evaluated anti-diabetic effects of DIBc, a nano metal–organic framework, which is synthetized based on nanochelating technology.

Methods

High-fat diet and streptozotocin-induced diabetic rats were treated by DIBc or metformin for 6 weeks.

Results

DIBc decreased plasma glucose, triglyceride, cholesterol, high-density lipoprotein, and low-density lipoprotein compared with diabetic and metformin groups. In DIBc-treated rats, significant homeostasis model assessment of insulin resistance index, malondialdehyde, and tumor necrosis factor-α decrease was observed. H&E staining showed increased islet number and area in DIBc-treated rats compared with diabetic controls.

Conclusion

The results showed anti-diabetic effects of nanochelating-based framework. So DIBc, as a nano structure, has the capacity to be evaluated in future studies as a novel anti-diabetic agent.

Understanding the Pathological Basis of Neurological Diseases Through Diagnostic Platforms Based on Innovations in Biomedical Engineering: New Concepts and Theranostics Perspectives

The pace of advancement of genomics and proteomics together with the recent understanding of the molecular basis behind rare diseases could lead in the near future to significant advances in the diagnosing and treating of many pathological conditions. Innovative diagnostic platforms based on biomedical engineering (microdialysis and proteomics, biochip analysis, non-invasive impedance spectroscopy, etc.) are introduced at a rapid speed in clinical practice: this article primarily aims to highlight how such platforms will advance our understanding of the pathological basis of neurological diseases. An overview of the clinical challenges and regulatory hurdles facing the introduction of such platforms in clinical practice, as well as their potential impact on patient management, will complement the discussion on foreseeable theranostic perspectives. Indeed, the techniques outlined in this article are revolutionizing how we (1) identify biomarkers that better define the diagnostic criteria of any given disease, (2) develop research models, and (3) exploit the externalities coming from innovative pharmacological protocols (i.e., those based on monoclonal antibodies, nanodrugs, etc.) meant to tackle the molecular cascade so far identified.

Co-coating of receptor-targeted drug nanocarriers with anti-phagocytic moieties enhances specific tissue uptake versus non-specific phagocytic clearance

Nanocarriers (NCs) help improve the performance of therapeutics, but their removal by phagocytes in the liver, spleen, tissues, etc. diminishes this potential. Although NC functionalization with polyethylene glycol (PEG) lowers interaction with phagocytes, it also reduces interactions with tissue cells. Coating NCs with CD47, a protein expressed by body cells to avoid phagocytic removal, offers an alternative. Previous studies showed that coating CD47 on non-targeted NCs reduces phagocytosis, but whether this alters binding and endocytosis of actively-targeted NCs remains unknown. To evaluate this, we used polymer NCs targeted to ICAM-1, a receptor overexpressed in many diseases. Co-coating of CD47 on anti-ICAM NCs reduced macrophage phagocytosis by ∼50% for up to 24 h, while increasing endothelial-cell targeting by ∼87% over control anti-ICAM/IgG NCs. Anti-ICAM/CD47 NCs were endocytosed via the CAM-mediated pathway with efficiency similar (0.99-fold) to anti-ICAM/IgG NCs. Comparable outcomes were observed for NCs targeted to PECAM-1 or transferrin receptor, suggesting broad applicability. When injected in mice, anti-ICAM/CD47 NCs reduced liver and spleen uptake by ∼30-50% and increased lung targeting by ∼2-fold (∼10-fold over IgG NCs). Therefore, co-coating NCs with CD47 and targeting moieties reduces macrophage phagocytosis and improves targeted uptake. This strategy may significantly improve the efficacy of targeted drug NCs.

Green synthesis of biogenic silver nanomaterials using Raphanus sativus extract, effects of stabilizers on the morphology, and their antimicrobial activities

The present study explores the reducing and capping potentials of aqueous Raphanus sativus root extract for the synthesis of silver nanomaterials for the first time in the absence and presence of two stabilizers, namely, water-soluble starch and cetyltrimethylammonium bromide (CTAB). The surface properties of silver nanoparticles (AgNPs) were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy dispersion X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) techniques. The mean size of AgNPs, ranging from 3.2 to 6.0 nm, could be facilely controlled by merely varying the initial [extract], [CTAB], [starch], and [Ag(+)] ions. The agglomeration number, average number of silver atoms per nanoparticle, and changes in the fermi potentials were calculated and discussed. The AgNPs were evaluated for their antimicrobial activities against different pathogenic organisms. The inhibition action was due to the structural changes in the protein cell wall.

Advanced materials and processing for drug delivery: the past and the future

Design and synthesis of efficient drug delivery systems are of vital importance for medicine and healthcare. Materials innovation and nanotechnology have synergistically fueled the advancement of drug delivery. Innovation in material chemistry allows the generation of biodegradable, biocompatible, environment-responsive, and targeted delivery systems. Nanotechnology enables control over size, shape and multi-functionality of particulate drug delivery systems. In this review, we focus on the materials innovation and processing of drug delivery systems and how these advances have shaped the past and may influence the future of drug delivery.

Investigation of self-assembling proline- and glycine-rich recombinant proteins and peptides inspired by proteins from a symbiotic fungus using atomic force microscopy and circular dichroism spectroscopy

Fiber-forming proteins and peptides are being scrutinized as a promising source of building blocks for new nanomaterials. Arabinogalactan-like (AGL) proteins expressed at the symbiotic interface between plant roots and arbuscular mycorrhizal fungi have novel sequences, hypothesized to form polyproline II (PPII) helix structures. The functional nature of these proteins is unknown but they may form structures for the establishment and maintenance of fungal hyphae. Here we show that recombinant AGL1 (rAGL1) and recombinant AGL3 (rAGL3) are extended proteins based upon secondary structural characteristics determined by electronic circular dichroism (CD) spectroscopy and can self-assemble into fibers and microtubes as observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). CD spectroscopy results of synthetic peptides based on repeat regions in AGL1, AGL2 and AGL3 suggest that the synthetic peptides contain significant amounts of extended PPII helices and that these structures are influenced by ionic strength and, at least in one case, by concentration. Point mutations of a single residue of the repeat region of AGL3 resulted in altered secondary structures. Self-assembly of these repeats was observed by means of AFM and optical microscopy. Peptide (APADGK)(6) forms structures with similar morphology to rAGL1 suggesting that these repeats are crucial for the morphology of rAGL1 fibers. These novel self-assembling sequences may find applications as precursors for bioinspired nanomaterials.

Development of molecular imaging and nanomedicine in China

The rapid progress of molecular imaging (MI) and the application of nanotechnology in medicine have the potential to advance the foundations of diagnosis, treatment, and prevention of diseases. Although MI and biomedical nanotechnology are still in a formative phase in China, much has been achieved over the last decade. This article provides a commentary on the development and current status of nanomedicine in China, with a selective focus on Chinese nanoparticle synthesis technology, the development of imaging equipment, and the preclinical application of novel MI probes.