Chiral inorganic nanomaterials:Harnessing chirality-dependent interactions with living entities for biomedical applications

Chirality is an intriguing and fundamental property of natural matter,which is especially crucial in supporting the processes of living systems.The selective interactions between natural chiral compounds are widespread at all levels in living entities and play a vital role in biochemical reactions.The cutting-edge advancements in synthetic chiral inorganic nanostructures have led to significant progress in their applications within biological systems.These developments have unraveled chirality-dependent interactions at the nanoscale and molecular scale,providing a better understanding of intricate process of chiral selection in biological systems and demonstrating the potential of chiral inorganic nanostructures for life science applications.Herein,we summarize recent progress in understanding the chirality origin of inorganic chiral nanoparticles and the development of wet-chemical synthesis.We also discuss the captivating interaction between chiral inorganic nanostructures and biological entities at various scales.Finally,we discuss the challenges and potential of functional chiral nanomaterials for future biomedical and bioengineering applications,offering design ideas and a forecast for their future impact.

Synthesis, characteristics, and antibacterial activity of a rare-earth samarium/silver/titanium dioxide inorganic nanomaterials

An inorganic nanomaterials combination of Sm, Ag, and TiO2 was synthesized using supercritical fluid drying （SCFD） combined with solgel techniques. The structure, photocatalysis and bacteriostatic activity of the materials were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XRPS）, photocatalytic performance, and antibacterial activity experiments. The XRD results showed that the average particle diameter of Sm/Ag/TiO2 was 14.62 nm and Ag and Sm ions were dispersed on the surface of TiO2 in a highly dispersed, amorphous form. The TEM image showed that the size of the particle was 12 nm using the scherer formula. The XPS result showed that the element Sm was doped and Ag was loaded inorganic nanomaterials successfully. Sm/Ag/TiO2 exhibited optimal photocatalytic properties at 600 oC, the photocatalytic optimal proportion of Sm/Ag/TiO2 was 2：2：100. When the molar ratio was 2：2：100, the bacteriostatic circle diameter was 16 mm for Staphylococcus aureus, the minimum bacteriostatic concentration was 200μg/mL for white beads coccus, and the minimum bactericidal concentration was 2×10^4μg/mL for white beads coccus. The SEM results showed that the antibacterial material attached to the candida albicans cell surface, cells appeared fold deformation. Therefore the inorganic nanomaterials Sm/Ag/TiO2 had high temperature resistance, good photocatalytic and antibacterial characteristics in visible light.

Multifunctional inorganic nanomaterials for cancer photoimmunotherapy

Phototherapy and immunotherapy in combination is regarded as the ideal ther-apeutic modality to treat both primary and metastatic tumors.Immunother-apy uses different immunological approaches to stimulate the immune system to identify tumor cells for targeted elimination.Phototherapy destroys the pri-mary tumors by light irradiation,which induces a series of immune responses through triggering immunogenic cancer cell death.Therefore,when integrat-ing immunotherapy with phototherapy,a novel anti-cancer strategy called pho-toimmunotherapy(PIT)is emerging.This synergistic treatment modality can not only enhance the effectiveness of both therapies but also overcome their inherent limitations,opening a new era for the current anti-cancer therapy.Recently,the advancement of nanomaterials affords a platform for PIT.From all these nanomaterials,inorganic nanomaterials stand out as idealmediators in PIT due to their unique physiochemical properties.Inorganic nanomaterials can not only serve as carriers to transport immunomodulatory agents in immunotherapy owing to their excellent drug-loading capacity but also function as photother-mal agents or photosensitizers in phototherapy because of their great optical characteristics.In this review,the recent advances of multifunctional inorganic nanomaterial-mediated drug delivery and their contributions to cancer PIT will be highlighted.

Endowing inorganic nanomaterials with circularly polarized luminescence

Recently,materials with circularly polarized luminescence(CPL)properties have attracted substantial attention because they offer new perspectives in fundamental research and wide applications in photonics,bio-encoding,catalysis,and so forth.Such importance has recently promoted the development of CPL-active materials from the traditional realm of organics to newly released areas in inorganics.Due to the advantages of inorganic nanomaterials in stability,high luminescent quantum efficiency,material diversity,and the diversity of shapes and sizes,extensive research about CPL active inorganic nanomaterials has been done in the past decades leading to great signs of progress on synthesis,characterizations,and potential applications.In this review,therefore,we will thoroughly describe the general design principles of inorganic nanomaterials with CPL activity,basically according to the origins of chirality in inorganic nanomaterials:intrinsic chirality in inorganic nanomaterials,ligand-induced chirality,and structural chirality caused by the supramolecular assembly,respectively.The representative applications of the CPL-active inorganic nanomaterials are presented with respect to challenges,prospective,and problems that unsolved to date.

Applications of DNA Nanotechnology in Synthesis and Assembly of Inorganic Nanomaterials

In addition to its inherited genetic function, DNA is one of the smartest and most flexible self-assembling na- nomaterials with programmable and predictable features, for which, more and more scientists combine DNA with nanomaterials and put them into designing, synthesizing and assembling. In this review, four modes of action of DNA molecules are introduced in a figurative and intuitive way, based on the four different roles it plays in synthe- sis and assembly of nanomaterials： （a） smart linkers to guide nanoparticle assembly, （b） 2D or 3D scaffold with well-designed binding sites, （c） nucleation sites to directly facilitate Au/Pd/Ag/Cu nanowires, nanoparticles, nano- arrays and （d） serving as capping agents to prevent crystal growth, and control size and morphology. To be sure, this state-of-the-art combination of functional DNA molecules and inorganic nanomaterials greatly encouraged step towards the development of analytical science, life science, environmental science, and other promising field they can address. DNA-guided nanofabrication will eventually exceed expectations far beyond our scope in the near fu- ture.

Conductive Biomaterials as Bioactive Wound Dressing for Wound Healing and Skin Tissue Engineering

Conductive biomaterials based on conductive polymers,carbon nanomaterials,or conductive inorganic nanomaterials demonstrate great potential in wound healing and skin tissue engineering,owing to the similar conductivity to human skin,good antioxidant and antibacterial activities,electrically controlled drug delivery,and photothermal effect.However,a review highlights the design and application of conductive biomaterials for wound healing and skin tissue engineering is lacking.In this review,the design and fabrication methods of conductive biomaterials with various structural forms including film,nanofiber,membrane,hydrogel,sponge,foam,and acellular dermal matrix for applications in wound healing and skin tissue engineering and the corresponding mechanism in promoting the healing process were summarized.The approaches that conductive biomaterials realize their great value in healing wounds via three main strategies(electrotherapy,wound dressing,and wound assessment)were reviewed.The application of conductive biomaterials as wound dressing when facing different wounds including acute wound and chronic wound(infected wound and diabetic wound)and for wound monitoring is discussed in detail.The challenges and perspectives in designing and developing multifunctional conductive biomaterials are proposed as well.

Recent Progress of Inorganic Hole-Transport Materials for Perovskite Solar Cells

Perovskite solar cells (PSCs) have achieved significant progress in the past decade and a certified power conversion efficiency (PCE) of 26.0% has been achieved.The widely used organic hole transport materials (HTMs) in PSCs are typically sensitive to the moisture environment and continuous light exposure.In contrast,the inorganic HTMs benefiting from their outstanding merits,such as excellent environmental stability,are considered as alternatives and have attracted much attention in PSCs.In this review,we provide a comprehensive summary of the fundamental properties and recent progress of inorganic HTMs in n-i-p and p-i-n structured PSCs.Additionally,we emphasize the importance of inorganic HTMs in the development of highly efficient and stable PSCs.

Inorganic/organic combination:Inorganic particles/polymer composites for tissue engineering applications

Biomaterials have ushered the field of tissue engineering and regeneration into a new era with the development of advanced composites.Among these,the composites of inorganic materials with organic polymers present unique structural and biochemical properties equivalent to naturally occurring hybrid systems such as bones,and thus are highly desired.The last decade has witnessed a steady increase in research on such systems with the focus being on mimicking the peculiar properties of inorganic/organic combination composites in nature.In this review,we discuss the recent progress on the use of inorganic particle/polymer composites for tissue engineering and regenerative medicine.We have elaborated the advantages of inorganic particle/polymer composites over their organic particle-based composite counterparts.As the inorganic particles play a crucial role in defining the features and regenerative capacity of such composites,the review puts a special emphasis on the various types of inorganic particles used in inorganic particle/polymer composites.The inorganic particles that are covered in this review are categorised into two broad types(1)solid(e.g.,calcium phosphate,hydroxyapatite,etc.)and(2)porous particles(e.g.,mesoporous silica,porous silicon etc.),which are elaborated in detail with recent examples.The review also covers other new types of inorganic material(e.g.,2D inorganic materials,clays,etc.)based polymer composites for tissue engineering applications.Lastly,we provide our expert analysis and opinion of the field focusing on the limitations of the currently used inorganic/organic combination composites and the immense potential of new generation of composites that are in development.

Maillard reaction-derived laser lithography for printing functional inorganics

Photopolymerization-based additive printing of functional inorganics has drawn great attention in recent years and one important challenge is the photoresin loading with diverse inorganics. Here, we introduce a Maillard reaction-derived laser lithography strategy for an unprecedented direct printing of diverse inorganic compounds. The sugar-assisted laser lithography(SLL) is powerful to carry choice metal ions and versatile for the generation of patterned inorganic materials comprising metal oxides,metal sulfides, and metal nitrides, characterized by ferroelectric, magnetic, semiconductivity, superconductivity, or other properties. The material architecture is flexibly manipulated by the laser intensity, power, printing speed, precursor solution, and computer-aided design to satisfy the practical requirements. This work demonstrates a new possibility for the further development of laser lithography in the directly printing of feature-rich inorganic materials and devices.